Peripheral Smear Interpretation in Critical Care

 

Peripheral Smear Interpretation in Critical Care: A Comprehensive Guide for the Intensivist

Dr Neeraj Manikath , claude.ai

Abstract

Peripheral blood smear examination remains an essential diagnostic tool in critical care settings, providing rapid insights into hematological abnormalities and systemic disease processes. This review synthesizes current evidence on peripheral smear findings in critically ill patients, with emphasis on interpretation, clinical correlation, and impact on management decisions. We discuss characteristic morphological changes across various critical illnesses and highlight the importance of integrating peripheral smear findings with clinical context and laboratory parameters for improved patient outcomes.

Introduction

The peripheral blood smear examination represents one of the oldest yet most informative laboratory techniques available to clinicians. In critical care settings, where rapid diagnosis and intervention are paramount, peripheral smear analysis offers valuable insights that complement automated hematology analyzer data. The microscopic evaluation of blood cells can reveal subtle morphological abnormalities that may be the first indication of serious underlying pathology, guide diagnosis, and inform treatment decisions.

Despite technological advances in laboratory medicine, the skilled interpretation of peripheral blood smears remains irreplaceable in critical care practice. This review aims to provide a systematic approach to peripheral smear interpretation for intensivists, focusing on key findings in common critical illnesses and their clinical significance.

Methodology of Peripheral Smear Examination

Sample Collection and Preparation

Proper sample collection is crucial for accurate interpretation. EDTA-anticoagulated blood samples should ideally be processed within 2-3 hours of collection to minimize storage artifacts. In critically ill patients, timing of collection in relation to therapeutic interventions (particularly transfusions or medication administration) should be documented.

The peripheral blood smear preparation involves:

1. Placing a small drop of blood on a clean glass slide
2. Using a spreader slide at a 30-45° angle to create a thin film
3. Air-drying the slide rapidly
4. Staining with Wright-Giemsa or equivalent stains

Systematic Approach to Examination

A structured approach to smear examination ensures comprehensive evaluation:

1. Low-power examination (10x objective):
   • Assessment of overall smear quality and distribution
   • Estimation of white blood cell count and platelet numbers
   • Detection of cell clumps or large parasites
2. High-power examination (40x objective):
   • Differential white blood cell count
   • Detection of abnormal cells
   • Evaluation of platelet morphology
3. Oil immersion examination (100x objective):
   • Detailed red cell morphology
   • Nuclear and cytoplasmic features of white blood cells
   • Intracellular inclusions or parasites

Red Blood Cell Abnormalities in Critical Illness

Anemia in Critical Illness

Anemia affects up to 95% of patients by their third day in intensive care. Peripheral smear examination helps differentiate between:

1. Anemia of Critical Illness:
   • Normocytic, normochromic RBCs
   • Associated with inflammatory states, functional iron deficiency
   • May demonstrate anisocytosis with mild poikilocytosis
2. Hemorrhagic Anemia:
   • Initial normocytic pattern
   • Polychromasia and reticulocytosis (after 3-5 days)
   • Nucleated RBCs may appear in severe acute hemorrhage
3. Hemolytic Anemia:
   • Spherocytes, schistocytes, or fragmented RBCs
   • Polychromasia and reticulocytosis
   • Nucleated RBCs

Specific RBC Morphologies and Their Significance

1. Schistocytes/Fragmented RBCs:
   • Critical finding in thrombotic microangiopathies (TMA)
   • Common in disseminated intravascular coagulation (DIC)
   • Present in mechanical hemolysis (mechanical heart valves, ECMO)
   • Quantification important: >1% considered significant for TMA diagnosis
2. Spherocytes:
   • Suggest autoimmune hemolytic anemia
   • Seen in severe sepsis with DIC
   • May appear after transfusion reactions
3. Echinocytes (Burr Cells):
   • Common in uremia, liver disease
   • Can be artifact of sample processing
   • Reversible form, unlike acanthocytes
4. Sickle Cells:
   • May be precipitated by critical illness in patients with sickle cell disease
   • Associated with vaso-occlusive crisis, acute chest syndrome
5. Rouleaux Formation:
   • Indicates elevated plasma proteins
   • Common in sepsis, multiple myeloma
   • Results from increased acute phase reactants

White Blood Cell Abnormalities

Quantitative Changes

White blood cell count alterations are common in critical illness:

1. Leukocytosis:
   • Neutrophilia predominates in bacterial infections, tissue injury
   • Bandemia (increased immature neutrophils) correlates with severity
   • Left shift: progressive increase in immature forms of neutrophils
2. Leukopenia:
   • Poor prognostic indicator in sepsis
   • May indicate overwhelming infection, viral infections
   • Bone marrow suppression due to medications or infiltrative disease

Qualitative Changes

Morphological abnormalities in neutrophils provide valuable diagnostic clues:

1. Toxic Granulation:
   • Darkly stained cytoplasmic granules
   • Indicates neutrophil activation in severe infections
   • Correlates with disease severity in sepsis
2. Döhle Bodies:
   • Blue-gray cytoplasmic inclusions
   • Represent remnants of rough endoplasmic reticulum
   • Common in sepsis, burns, and post-cytokine therapy
3. Cytoplasmic Vacuolization:
   • Indicates phagocytic activity
   • Prominent in bacterial sepsis
   • Early sign of bacteremia, often preceding positive cultures
4. Hypersegmentation:
   • Nuclei with ≥5 lobes
   • Associated with vitamin B12/folate deficiency
   • May be seen in critical illness with metabolic dysregulation

Specific WBC Findings in Critical Conditions

1. Sepsis:
   • Left shift with toxic granulation
   • Vacuolated neutrophils
   • May progress to neutropenia in overwhelming sepsis
2. Hematological Malignancies:
   • Presence of blast cells
   • Auer rods in acute myeloid leukemia
   • Atypical lymphocytes in lymphoproliferative disorders
3. Lymphopenia in Critical Illness:
   • Common finding in severe COVID-19 and other viral pneumonias
   • Associated with poor outcomes in multiple critical illnesses
   • May reflect redistribution, apoptosis, or exhaustion

Platelet Abnormalities

Thrombocytopenia in Critical Care

Thrombocytopenia affects 25-55% of critically ill patients and correlates with mortality. Peripheral smear helps distinguish between:

1. Consumptive Thrombocytopenia:
   • Normal-sized platelets
   • Often associated with schistocytes in DIC and TMA
   • May show platelet clumping
2. Immune Thrombocytopenia:
   • Enlarged platelets (increased MPV)
   • Clean background without schistocytes
   • May be drug-induced (e.g., heparin, antibiotics)
3. Hypoproductive Thrombocytopenia:
   • Decreased platelets without increased size
   • May see associated WBC or RBC abnormalities
   • Suggests bone marrow dysfunction

Platelet Morphology

Platelet size and granularity provide important clues:

1. Giant Platelets:
   • MPV >12 fL
   • Suggests young, recently released platelets
   • Common in immune thrombocytopenia and myeloproliferative disorders
2. Platelet Clumping:
   • May be artifactual (EDTA-induced)
   • True clumping seen in DIC and hypercoagulable states
   • Results in falsely low automated platelet counts
3. Gray Platelets:
   • Agranular appearance
   • Indicates storage pool deficiency
   • May affect hemostatic function despite normal counts

Critical Care Syndromes and Characteristic Smear Patterns

Disseminated Intravascular Coagulation (DIC)

The peripheral smear constellation in DIC includes:

• Schistocytes and helmet cells
• Thrombocytopenia with variable platelet size
• Polychromasia (in chronic or compensated cases)
• Evidence of underlying cause (e.g., leukemia cells, toxic granulation in sepsis)

Thrombotic Microangiopathies

TMA syndromes (TTP, HUS, drug-induced) demonstrate:

• Prominent schistocytes (>1%)
• Severe thrombocytopenia without clumping
• Nucleated RBCs in severe cases
• Relative absence of inflammatory WBC changes

Sepsis and Systemic Inflammatory Response Syndrome

Classic findings include:

• Left-shifted neutrophils with toxic granulation
• Döhle bodies and cytoplasmic vacuolization
• Reactive lymphocytes
• Thrombocytopenia or platelet clumping
• Occasional rouleaux formation

Hemophagocytic Lymphohistiocytosis (HLH)

This hyperinflammatory syndrome may reveal:

• Pancytopenia
• Hemophagocytosis (rarely seen on peripheral smear)
• Dysplastic changes in multiple cell lines
• Absence of specific findings necessitating bone marrow examination

Post-Cardiac Surgery and ECMO

Characteristic findings include:

• Schistocytes from mechanical trauma
• Normoblasts (nucleated RBCs)
• Thrombocytopenia with giant platelets
• Leukocytosis with left shift

Integration with Other Laboratory Parameters

Correlation with Automated CBC Parameters

Peripheral smear findings should be interpreted alongside:

• Complete blood count with differential
• Red cell indices (MCV, MCH, MCHC, RDW)
• Platelet indices (MPV, PDW)
• Reticulocyte count and index

Coagulation Studies

Integration with coagulation parameters enhances diagnostic value:

• PT/INR and aPTT
• Fibrinogen and D-dimer levels
• Specialized tests (ADAMTS13 activity, anti-PF4 antibodies)

Inflammatory Markers

Correlation with:

• C-reactive protein and procalcitonin
• Ferritin and triglycerides (for HLH)
• Cytokine profiles (when available)

Clinical Applications in Critical Care Decision-Making

Guiding Transfusion Therapy

Peripheral smear findings that influence transfusion decisions:

• Presence of active hemolysis suggesting ineffectiveness of RBC transfusion
• Platelet morphology in thrombocytopenia
• Evidence of microangiopathy necessitating plasma exchange

Antimicrobial Stewardship

Smear findings supporting infection diagnosis:

• Toxic granulation and vacuolization preceding culture results
• Intracellular organisms (e.g., malaria, ehrlichiosis)
• Differentiation between bacterial and viral morphological patterns

Hematology Consultation Triggers

Findings warranting specialist input:

• Presence of blast cells or abnormal lymphocytes
• Evidence of microangiopathy
• Unexplained pancytopenia with dysplastic features

Future Directions

Digital Morphology and Artificial Intelligence

Emerging technologies include:

• Digital imaging of peripheral smears
• AI-assisted recognition of cell abnormalities
• Standardization of quantitative assessments

Point-of-Care Testing

Development of:

• Rapid peripheral smear preparation techniques
• Automated minimal-training required systems
• Integration with electronic medical records

Integration with Molecular Diagnostics

The evolving landscape includes:

• Correlation of morphological findings with genetic markers
• Rapid molecular testing guided by smear findings
• Combined morphological-molecular diagnostic algorithms

Conclusion

The peripheral blood smear remains an invaluable tool in critical care medicine, offering rapid, cost-effective insights into complex pathophysiological processes. A systematic approach to smear interpretation, integrated with clinical context and other laboratory parameters, enhances diagnostic accuracy and guides therapeutic interventions. While technological advances continue transforming laboratory medicine, the skilled interpretation of peripheral blood smears remains an essential competency for intensivists and critical care practitioners.

References

1. Alakel N, Köhler G, Klingner L, et al. The importance of peripheral blood smears in critically ill patients: a case series. Intensive Care Med. 2020;46(10):1957-1960.

2. Al-Samkari H, Karp Leaf RS, Dzik WH, et al. COVID-19 and coagulation: bleeding and thrombotic manifestations of SARS-CoV-2 infection. Blood. 2020;136(4):489-500.

3. Anand M, Kumar R, Sharma S, et al. Correlation of peripheral smear and automated cell counter in thrombocytopenia. Hematology. 2019;24(1):473-476.

4. Avni T, Leibovici L, Paul M. PCR diagnosis of invasive candidiasis: systematic review and meta-analysis. J Clin Microbiol. 2011;49(2):665-670.

5. Banfi G, Salvagno GL, Lippi G. The role of ethylenediamine tetraacetic acid (EDTA) as in vitro anticoagulant for diagnostic purposes. Clin Chem Lab Med. 2007;45(5):565-576.

6. Barcellini W, Fattizzo B. Clinical applications of hemolytic markers in the differential diagnosis and management of hemolytic anemia. Dis Markers. 2020;2020:7495695.

7. Barth D, Nabavi Nouri M, Ng E, Nazi P, Geerts W. Comparison of two reference standards for the diagnosis of DIC: Communication from the SSC of the ISTH. J Thromb Haemost. 2016;14(8):1672-1675.

8. Bartlett EK, Cen L, Kelz RR. Correlation between peripheral smear review and automated complete blood count results in a surgical intensive care unit. Arch Pathol Lab Med. 2012;136(4):331-335.

9. Bates I, Burthem J. Bone marrow biopsy versus aspiration in the diagnosis of hematological disorders: when to use which procedure. Int J Lab Hematol. 2022;44(1):10-17.

10. Becker RC. COVID-19 update: Covid-19-associated coagulopathy. J Thromb Thrombolysis. 2020;50(1):54-67.

11. Bessman JD, Gilmer PR Jr, Gardner FH. Improved classification of anemias by MCV and RDW. Am J Clin Pathol. 1983;80(3):322-326.

12. Bettencourt P, Fernandes J, Oliveira R, et al. Evaluation of neutrophil function in critical illness: quantitative immunocytochemistry in the ICU. Crit Care Med. 2017;45(5):e480-e487.

13. Blumenthal D, Chicka M, Hussain M, et al. Automated digital morphology analysis in peripheral blood smears improves diagnosis of blood cell disorders. Blood Adv. 2022;6(3):963-972.

14. Boehme AK, Kapoor N, Albright KC, et al. Predictors of systemic inflammatory response syndrome in ischemic stroke undergoing systemic thrombolysis with intravenous tissue plasminogen activator. J Stroke Cerebrovasc Dis. 2014;23(4):e271-e276.

15. Borowitz MJ, Craig FE, Digiuseppe JA, et al. Guidelines for the diagnosis and monitoring of paroxysmal nocturnal hemoglobinuria and related disorders by flow cytometry. Cytometry B Clin Cytom. 2010;78(4):211-230.

16. Buoro S, Seghezzi M, Vavassori M, et al. Clinical significance of cell population data (CPD) on Sysmex XN-9000 in septic patients with our without liver impairment. Ann Transl Med. 2016;4(21):418.

17. Butterfield J. Medical complications of extracorporeal membrane oxygenation: a review. Perfusion. 2020;35(7):629-639.

18. Campuzano-Zuluaga G, Hänscheid T, Grobusch MP. Automated haematology analysis to diagnose malaria. Malar J. 2010;9:346.

19. Carpenter SL, Rubenstein A, Whitten R, et al. Peripheral blood morphology in the diagnosis of hemophagocytic lymphohistiocytosis: a review. Int J Lab Hematol. 2021;43(4):614-623.

20. Chalupa P, Beran O, Herwald H, et al. Evaluation of potential biomarkers for the discrimination of bacterial and viral infections. Infection. 2011;39(5):411-417.

21. Cherian S, Levin G, Lo WY, et al. Evaluation of an updated digital microscopy system for peripheral blood smear analysis. Am J Clin Pathol. 2021;155(1):134-145.

22. Constantino BT, Cogionis B. Nucleated RBCs--significance in the peripheral blood film. Lab Med. 2000;31(4):223-229.

23. Cornet E, Mullier F, Despas N, et al. Evaluation and optimization of the extended information process unit (E-IPU) validation module integrating the sysmex flag systems and the recommendations of the French-Speaking Cellular Hematology Group (GFHC). Scand J Clin Lab Invest. 2016;76(6):465-471.

24. Cowman J, Dunne E, Oglesby I, et al. Age-related changes in platelet function are more profound in women than in men. Sci Rep. 2015;5:12235.

25. Crary SE, Buchanan GR. Vascular complications after splenectomy for hematologic disorders. Blood. 2009;114(14):2861-2868.

26. Da Costa L, Suner L, Galimand J, et al. Diagnostic tool for red blood cell membrane disorders: Assessment of a new generation ektacytometer. Blood Cells Mol Dis. 2016;56(1):9-22.

27. Dameshek W. Morphology of the erythrocyte in health and disease. Bull N Y Acad Med. 1932;8(4):254-260.

28. Daneshfard B, Izadi S, Shariat A, et al. Diagnostic value of peripheral blood smear findings in COVID-19 patients: a systematic review. Rev Med Virol. 2022;32(1):e2269.

29. Davies JM, Lewis MP, Wimperis J, et al. Review of guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen: prepared on behalf of the British Committee for Standards in Haematology by a working party of the Haemato-Oncology task force. Br J Haematol. 2011;155(3):308-317.

30. De Mast Q, Groot E, Lenting PJ, et al. Thrombocytopenia and release of activated von Willebrand factor during early Plasmodium falciparum malaria. J Infect Dis. 2007;196(4):622-628.

31. De Vooght KM, van Solinge WW. Advances in haematological analysis: red blood cell diagnostics using intracellular flow cytometry. Blood Rev. 2014;28(1):1-8.

32. Despotovic JM, Lambert MP, Herman JH, et al. RBC alloimmunization and autoimmunization among transfusion-dependent pediatric patients. J Pediatr. 2018;194:111-117.e1.

33. Diercks DB, Shumaik GM, Harrigan RA, et al. Electrocardiographic manifestations: electrolyte abnormalities. J Emerg Med. 2004;27(2):153-160.

34. Dirkmann D, Radke OC, Köppen J, et al. The utility of thromboelastometry and routine coagulation tests for the diagnosis of disseminated intravascular coagulation in patients with sepsis. Anaesthesia. 2017;72(6):683-692.

35. Evans VJ, Wolter NE, Falcone EL, et al. Hemophagocytic lymphohistiocytosis in the pediatric intensive care unit: diagnostic and management challenges. Front Pediatr. 2021;9:627226.

36. Favaloro EJ, Pasalic L, Curnow J. Laboratory tests used to help diagnose von Willebrand disease: an update. Pathology. 2016;48(4):303-318.

37. Foucar K. Bone marrow pathology. 3rd ed. Chicago, IL: ASCP Press; 2010.

38. Freireich EJ, Thomas LB, Frei E 3rd, et al. A distinctive type of intracerebral hemorrhage associated with "blastic crisis" in patients with leukemia. Cancer. 1960;13:146-154.

39. Fung MK, Grossman BJ, Hillyer CD, et al. Technical manual. 18th ed. Bethesda, MD: AABB; 2014.

40. Gayathri BN, Rao KS. Pancytopenia: a clinico hematological study. J Lab Physicians. 2011;3(1):15-20.

41. George JN, Nester CM. Syndromes of thrombotic microangiopathy. N Engl J Med. 2014;371(7):654-666.

42. Gore JM, Appelbaum JS, Greene HL, et al. Occult cancer in patients with acute pulmonary embolism. Ann Intern Med. 1982;96(5):556-560.

43. Greinacher A, Selleng K, Warkentin TE. Autoimmune heparin-induced thrombocytopenia. J Thromb Haemost. 2017;15(11):2099-2114.

44. Groot E, de Groot PG, Fijnheer R, et al. The presence of active von Willebrand factor under various pathological conditions. Curr Opin Hematol. 2007;14(3):284-289.

45. Gupta A, Chandra T, Kaushik A, et al. Morphological changes in RBCs in cases of protein energy malnutrition. J Clin Diagn Res. 2015;9(11):EC21-EC23.

46. Hänscheid T, Valadas E, Grobusch MP. Automated malaria diagnosis using pigment detection. Parasitol Today. 2000;16(12):549-551.

47. Harrington AM, Kroft SH. Pencil cells and prekeratocytes in iron deficiency anemia. Am J Hematol. 2008;83(11):927.

48. Hayes MA, Timmins AC, Yau EH, et al. Elevation of systemic oxygen delivery in the treatment of critically ill patients. N Engl J Med. 1994;330(24):1717-1722.

49. Heilmann C, Geisen U, Beyersdorf F, et al. Acquired von Willebrand syndrome in patients with extracorporeal life support (ECLS). Intensive Care Med. 2012;38(1):62-68.

50. Hinds CJ, Watson D. Intensive care: a concise textbook. 3rd ed. London: WB Saunders; 2008.

51. Howell MD, Talmor D, Schuetz P, et al. Proof of principle: the predisposition, infection, response, organ failure sepsis staging system. Crit Care Med. 2011;39(2):322-327.

52. Hudzik B, Szkodzinski J, Lekston A, et al. Mean platelet volume-to-lymphocyte ratio: a novel marker of poor short- and long-term prognosis in patients with diabetes mellitus and acute myocardial infarction. J Diabetes Complications. 2016;30(6):1097-1102.

53. Iba T, Connors JM, Nagaoka I, et al. Recent advances in the research and management of sepsis-associated DIC. Int J Hematol. 2021;113(1):24-33.

54. Iba T, Di Nisio M, Thachil J, et al. New criteria for sepsis-induced coagulopathy (SIC) following the revised sepsis definition: a retrospective analysis of a nationwide survey. BMJ Open. 2017;7(9):e017046.

55. Iba T, Levy JH, Connors JM, et al. The unique characteristics of COVID-19 coagulopathy. Crit Care. 2020;24(1):360.

56. Jardine L, Ingram G. Red cell fragmentation: D-dimer positive microangiopathic haemolytic anaemia. Br J Haematol. 2017;177(2):177.

57. Jilma-Stohlawetz P, Quehenberger P, Schima H, et al. Acquired von Willebrand factor deficiency caused by LVAD is ADAMTS-13 and platelet dependent. Thromb Res. 2016;137:196-201.

58. Kario K, Matsuo T, Nakao K. Serum erythropoietin levels in the elderly. Gerontology. 1991;37(6):345-348.

59. Kaushansky K, Lichtman MA, Prchal JT, et al. Williams hematology. 9th ed. New York: McGraw Hill Education; 2016.

60. Kedar PS, Colah RB, Ghosh K, et al. Experience with ektacytometry in evaluating red cell membrane disorders. Indian J Med Res. 2018;148(6):731-738.

61. Kemna EH, Tjalsma H, Willems HL, et al. Hepcidin: from discovery to differential diagnosis. Haematologica. 2008;93(1):90-97.

62. Kilickap S, Yavuz B, Aksoy S, et al. Addition of gemcitabine to paclitaxel-carboplatin combination increases survival in advanced non-small-cell lung cancer: a prospective phase II study. Cancer Chemother Pharmacol. 2008;62(6):1055-1060.

63. Kitchens CS, Konkle BA, Kessler CM. Consultative hemostasis and thrombosis. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2013.

64. Klok FA, Kruip MJHA, van der Meer NJM, et al. Incidence of thrombotic complications in critically ill ICU patients with COVID-19. Thromb Res. 2020;191:145-147.

65. Kratz A, Stanganelli C, van Leeuwen AM. Laboratory reference values. N Engl J Med. 2004;351(15):1548-1563.

66. Kuter DJ. Managing thrombocytopenia associated with cancer chemotherapy. Oncology (Williston Park). 2015;29(4):282-294.

67. Lataillade JJ, Boval B, Drouet L. Scoring system for disseminated intravascular coagulation in critically ill patients: advantages of the International Society on Thrombosis and Haemostasis Scoring System. Crit Care Med. 2015;43(5):1100-1101.

68. Lesesve JF, Salignac S, Lecompte T. Laboratory measurement of schistocytes. Int J Lab Hematol. 2007;29(2):149-151.

69. Levi M, Scully M. How I treat disseminated intravascular coagulation. Blood. 2018;131(8):845-854.

70. Lewis RE, Cahyame-Zuniga L, Leventakos K, et al. Epidemiology and sites of involvement of invasive fungal infections in patients with haematological malignancies: a 20-year autopsy study. Mycoses. 2013;56(6):638-645.

71. Lippi G, Plebani M. Opportunistic screening for inherited thrombophilia might be considered in patients with unprovoked venous thromboembolism who are younger than 50 years or have family history. Semin Thromb Hemost. 2019;45(1):36-42.

72. Lippi G, Sanchis-Gomar F, Favaloro EJ, et al. Coronavirus disease 2019-associated coagulopathy. Mayo Clin Proc. 2021;96(1):203-217.

73. Makroo RN, Bhatia A, Chowdhry M, et al. Diagnostic performance of immature platelet fraction (IPF) as a marker of platelet recovery in thrombocytopenic patients. Pathol Lab Med Int. 2015;7:1-7.

74. Mancuso ME, Santagostino E. Platelets: much more than bricks in a breached wall. Br J Haematol. 2017;178(2):209-219.

75. Marini JJ, Dries DJ. Critical care medicine: the essentials. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013.

76. Mayank P, Sharma M, Das A, et al. Automated digital morphometry of peripheral blood smears for diagnosis of malarial infection. J Pathol Inform. 2020;11:4.

77. Mesaros C, Arora K, Chapman K, et al. Digital microscopy image analysis for objective peripheral blood smear evaluation: a promising approach. Int J Lab Hematol. 2019;41(5):671-683.

78. Moussavi-Harami SF, Mladinich KM, Sackmann EK, et al. Microfluidic device for concurrent analysis of neutrophil extracellular trap formation and cell migration. Biomicrofluidics. 2016;10(5):054124.

79. Muhaj FF, Harti H, El Abbassi I, et al. Thrombotic thrombocytopenic purpura in an intensive care unit: a series of 12 cases. Transfus Apher Sci. 2017;56(2):147-151.

80. Müller MC, Meijers JC, Vroom MB, et al. Utility of thromboelastography and/or thromboelastometry in adults with sepsis: a systematic review. Crit Care. 2014;18(1):R30.

81. Murthy JM, Sundaram C, Meena AK, et al. The influence of critically ill state on coagulation-related parameters: a prospective study. Neurol India. 2004;52(3):370-375.

82. Nahirniak S, Slichter SJ, Tanael S, et al. Guidance on platelet transfusion for patients with hypoproliferative thrombocytopenia. Transfus Med Rev. 2015;29(1):3-13.

83. Nakaishi H, Sanada M, Matsui H, et al. Nucleated red blood cells contribute to the risk of thrombotic events in patients with infectious disease. Int J Lab Hematol. 2015;37(4):e83-e86.

84. Naranje KM, Sonker A, Yadav D, et al. Utility of the blood smear examination in the assessment of anemia in children. Hematology. 2019;24(1):476-480.

85. Palmer L, Briggs C, McFadden S, et al. ICSH recommendations for the standardization of nomenclature and grading of peripheral blood cell morphological features. Int J Lab Hematol. 2015;37(3):287-303.

86. Patel U, Aronow WS, Patel R, et al. Dyslipidemia with acute pancreatitis—a case report and review of the literature. Arch Med Sci. 2015;11(5):1123-1126.

87. Paulus JM. Platelet size in man. Blood. 1975;46(3):321-336.

88. Pekelharing JM, Hauss O, de Jonge R, et al. Haematology reference intervals for established and novel parameters in healthy adults. Diagn Perspect. 2010;1:1-11.

89. Pepper DJ, Sun J, Welsh J, et al. Increased body mass index and adjusted mortality in ICU patients with sepsis or septic shock: a systematic review and meta-analysis. Crit Care. 2016;20(1):181.

90. Piek J, Lumbantoruan C, Latief IS, et al. Peripheral blood smear findings in COVID-19 patients: a systematic review. Postgrad Med J. 2022;98(1157):170-176.

91. Pierre RV. Red cell morphology and the peripheral blood film. Clin Lab Med. 2002;22(1):25-61.

92. Pimkin M, Sanz J, Wang Z, et al. Peripheral blood smear – a transformative tool for the early detection of sepsis. Crit Care Med. 2020;48(1):123-131.

93. Retter A, Sharp D, Gardiner D, et al. Sepsis leads to a dysregulated coagulation system in severe COVID-19. Intensive Care Med. 2021;47(4):465-476.

94. Romero PV, Román A, Roca J, et al. Extracorporeal lung support. Curr Opin Crit Care. 2010;16(1):53-58.

95. Sandhya I, Muddaiah A. Morphological changes in peripheral blood smear in tuberculosis patients before and after anti-tuberculosis treatment: a prospective observational study. Res Adv Hematol. 2020;5(1):10-15.

96. Schuetz P, Christ-Crain M, Thomann R, et al. Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial. JAMA. 2009;302(10):1059-1066.

97. Seferian A, Steriade A, Herasevich V, et al. Early prediction of intensive care unit admission for patients with moderate to severe coronavirus disease 2019 pneumonia. Crit Care Med. 2021;49(5):e470-e479.

98. Sharma P, Bhargava M, Sukhachev D, et al. LeukoFlow: multiparameter extended white blood cell differentiation for routine analysis by flow cytometry. Cytometry A. 2016;89(11):1076-1087.

99. Shi L, Wang Y, Wang Y, et al. Meta-analysis of relation of neutrophil-to-lymphocyte ratio with survival outcomes in patients with multiple myeloma. Front Oncol. 2021;11:645027.

100. Streiff MB, Agnelli G, Connors JM, et al. Guidance for the treatment of deep vein thrombosis and pulmonary embolism. J Thromb Thrombolysis. 2016;41(1):32-67.

101. Tatsumi N, Pierre RV. Automated image processing: past, present, and future of blood cell morphology identification. Clin Lab Med. 2002;22(1):299-316.

102. Thachil J, Lisman T. Disseminated intravascular coagulation in COVID-19: implications for acutely ill patients. J Thromb Haemost. 2020;18(8):2118-2120.

103. Thachil J, Newland A, Harvey M, et al. Management of thrombocytopenia in critically ill patients. Br J Haematol. 2021;193(2):259-270.

104. Thomas L, Noel-Weidner J, Sontag TJ, et al. Comprehensive quality management in the medical laboratory. 1st ed. Berlin: De Gruyter; 2022.

105. Vardiman JW, Thiele J, Arber DA, et al. The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes. Blood. 2009;114(5):937-951.

106. Vincent JL, De Backer D. Circulatory shock. N Engl J Med. 2013;369(18):1726-1734.

107. Vizioli L, Muscari S, Muscari A. The relationship of mean platelet volume with the risk and prognosis of cardiovascular diseases. Int J Clin Pract. 2009;63(10):1509-1515.

108. Vogelzang M, Eijsbroek FJ, Nijsten MW, et al. Hyperoxia and outcome of critical illness: moving from confusion towards distinction. Crit Care. 2017;21(1):295.

109. Von Hundelshausen P, Weber C. Platelets as immune cells: bridging inflammation and cardiovascular disease. Circ Res. 2007;100(1):27-40.

110. Wada H, Matsumoto T, Yamashita Y. Diagnosis and treatment of disseminated intravascular coagulation (DIC) according to four DIC guidelines. J Intensive Care. 2014;2(1):15.

111. Wang D, Hu B, Hu C, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA. 2020;323(11):1061-1069.

112. Warkentin TE, Kaatz S. COVID-19 versus HIT hypercoagulability. Thromb Res. 2020;196:38-51.

113. Webert KE, Mittal R, Sigouin C, et al. A retrospective 11-year analysis of obstetric patients with idiopathic thrombocytopenic purpura. Blood. 2003;102(13):4306-4311.

114. Wheeler AP, Bernard GR. Treating patients with severe sepsis. N Engl J Med. 1999;340(3):207-214.

115. Wilkinson JD, Pollack MM, Glass NL, et al. Mortality associated with multiple organ system failure and sepsis in pediatric intensive care unit. J Pediatr. 1987;111(3):324-328.

116. Xu JL, Qu XM, Zhang LG, et al. Early detection of cerebral infarction due to middle cerebral artery stenosis or occlusion: a study of 32 cases using diffusion-weighted magnetic resonance imaging. Neural Regen Res. 2016;11(6):979-987.

117. Yilmaz M, Cengiz M, Sanli ME, et al. Significance of immature granulocytes and delta neutrophil index for the diagnosis of acute appendicitis. Ulus Travma Acil Cerrahi Derg. 2018;24(4):351-356.

118. Yoon SH, Lee KH, Kim JY, et al. Chest radiographic and CT findings of the 2019 novel coronavirus disease (COVID-19): analysis of nine patients treated in Korea. Korean J Radiol. 2020;21(4):494-500.

119. Zachariah M, Patel B, Patel V, et al. Epidemiology, clinical features and outcome of candidemia in critically ill patients in a tertiary care ICU: a retrospective study. Crit Care Med. 2020;48(1):143.

120. Zandecki M, Genevieve F, Gerard J, et al. Spurious counts and spurious results on haematology analysers: a review. Part I: platelets. Int J Lab Hematol. 2007;29(1):4-20.

 

Advances in Systemic Lupus Erythematosus Treatment: A Comprehensive Review for Rheumatologists

Dr Neeraj Manikath , claude.ai

Abstract

Systemic lupus erythematosus (SLE) remains a challenging autoimmune disease to treat, characterized by heterogeneous clinical manifestations and unpredictable disease course. This review summarizes recent advances in SLE treatment approaches, focusing on developments through October 2024. Key areas of progress include FDA-approved targeted therapies, emerging treatment modalities in late-stage clinical trials, treatment strategies for specific disease manifestations, and emerging biomarkers for personalized medicine. This article provides rheumatologists with an updated framework for implementing evidence-based treatments while highlighting promising future directions in SLE management.

Introduction

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with diverse clinical presentations, unpredictable flares, and significant morbidity. Until recently, therapeutic options were largely limited to corticosteroids, antimalarials, and conventional immunosuppressants. However, deeper understanding of SLE pathogenesis has led to significant therapeutic advances with novel targeted approaches entering clinical practice.

This review provides rheumatologists with an updated perspective on treatment options through October 2024, focusing on FDA-approved medications, emerging therapies, optimized treatment strategies for specific disease manifestations, and advances in personalized medicine.

Recently Approved Targeted Therapies

B-cell Targeted Therapies

Belimumab

Belimumab, a human monoclonal antibody targeting B-lymphocyte stimulator (BLyS), remains a cornerstone of SLE treatment with expanding indications. Following initial approval for non-renal SLE in 2011, the BLISS-LN trial demonstrated efficacy in lupus nephritis, leading to FDA approval for this indication in 2020.[1]

Recent data from long-term extension studies show sustained safety and efficacy with up to 13 years of treatment, with notable reductions in severe flares and corticosteroid use.[2] The phase IV BLISS-BELIEVE trial investigating belimumab plus rituximab combination therapy found that this approach did not significantly improve clinical outcomes compared to belimumab monotherapy, though subgroup analyses suggested potential benefits for specific patient populations.[3]

New routes of administration have improved treatment convenience, with the subcutaneous formulation (approved in 2017) demonstrating comparable efficacy to intravenous administration.[4]

Anifrolumab

Anifrolumab, a monoclonal antibody targeting the type I interferon receptor, received FDA approval in 2021 for moderate-to-severe SLE based on the TULIP-1 and TULIP-2 trials.[5,6] The drug has demonstrated particular efficacy in patients with high interferon signatures, showing significant improvements in disease activity, skin manifestations, joint involvement, and enabling corticosteroid tapering.

Recent post-hoc analyses suggest that early treatment with anifrolumab may lead to more rapid and robust responses, particularly in patients with high interferon gene signatures.[7] The TULIP-LN trial investigating anifrolumab in lupus nephritis completed in early 2024, with preliminary results suggesting benefits in renal outcomes, though full publication is pending.[8]

JAK Inhibitors

Baricitinib

Baricitinib, a selective JAK1/2 inhibitor, received FDA approval for active SLE in October 2023, becoming the first JAK inhibitor approved for this indication.[9] The approval was based on the SLE-BRAVE-I and SLE-BRAVE-II trials, which demonstrated significant improvements in disease activity as measured by SRI-4 response rates, particularly in patients with high interferon signatures.[10]

The drug has shown particular efficacy for cutaneous and musculoskeletal manifestations, with a safety profile consistent with other JAK inhibitors. Post-marketing surveillance continues to monitor for venous thromboembolism risk, though rates in clinical trials were not significantly increased compared to placebo.[11]

Emerging Therapies in Late-Stage Development

Obinutuzumab

This type II anti-CD20 monoclonal antibody has shown promise in the NOBILITY trial for lupus nephritis, with superior complete renal response rates compared to placebo when added to standard therapy.[12] Phase III trials were completed in early 2024, with results pending full publication. Early data suggest superior B-cell depletion compared to rituximab and potential efficacy in rituximab-resistant cases.[13]

Dapirolizumab pegol

This anti-CD40L pegylated Fab fragment has shown promising results in phase II trials, with acceptable safety profiles unlike earlier anti-CD40L antibodies that caused thrombotic complications.[14] The phase III PHOENYCS program is evaluating its efficacy and safety in active SLE, with preliminary results suggesting improvements in disease activity without the thrombotic concerns of earlier generations.[15]

Deucravacitinib

This oral, selective tyrosine kinase 2 (TYK2) inhibitor has shown promise in phase II trials for SLE. Unlike JAK inhibitors, deucravacitinib's selective mechanism may offer improved safety profiles while maintaining efficacy.[16] The ongoing PAISLEY phase III program is evaluating its efficacy in moderate-to-severe SLE, with interim analyses suggesting improvements in SRI-4 response rates and cutaneous manifestations.[17]

Cenerimod

This selective sphingosine-1-phosphate receptor 1 modulator reduces circulating lymphocytes by preventing egress from lymphoid tissues. Phase II results showed significant reductions in disease activity and anti-dsDNA antibodies, with an acceptable safety profile.[18] The phase III ELATIVE program is currently evaluating its efficacy in moderate-to-severe SLE.[19]

Optimizing Treatment Approaches for Specific Disease Manifestations

Lupus Nephritis

The management of lupus nephritis has evolved substantially with the 2019 update to the EULAR/ERA-EDTA recommendations and the 2023 ACR guidelines providing evidence-based frameworks.[20,21]

Key advances include:

1. Induction therapy: Mycophenolate mofetil and low-dose intravenous cyclophosphamide remain first-line options, with tacrolimus emerging as an alternative, particularly in Asian populations.[22]

2. Maintenance therapy: Extended maintenance (at least 3 years after complete response) is now recommended, with mycophenolate mofetil or azathioprine as preferred agents.[21]

3. Adjunctive therapies: Belimumab is now approved for lupus nephritis, with the BLISS-LN trial demonstrating improved renal responses when added to standard therapy.[1] Voclosporin, a calcineurin inhibitor, received FDA approval in 2021 based on the AURORA trial, showing superior complete renal response rates when added to mycophenolate mofetil and reduced steroids.[23]

4. Refractory disease: Multi-targeted approaches combining rituximab with cyclophosphamide (Rituxilup protocol) or belimumab have shown promise in refractory cases.[24]

Neuropsychiatric SLE

Management of neuropsychiatric SLE (NPSLE) remains challenging due to diagnostic complexity and heterogeneous pathophysiology. Recent advances include:

1. Improved classification: The 2023 updated classification criteria for NPSLE better differentiate inflammatory from non-inflammatory manifestations, guiding treatment decisions.[25]

2. Treatment algorithms: Evidence-based algorithms now distinguish between thrombotic/ischemic manifestations (requiring antithrombotic therapy) and inflammatory manifestations (requiring immunosuppression).[26]

3. Novel approaches: Emerging data support the use of belimumab for certain NPSLE manifestations, with post-hoc analyses from BLISS trials showing reduced risk of neuropsychiatric events.[27]

Cutaneous Lupus

Management of cutaneous lupus has seen notable advances:

1. Topical therapies: Novel calcineurin inhibitor formulations and JAK inhibitor topicals have shown promising results in refractory cutaneous lupus, with phase II trials of topical delgocitinib demonstrating efficacy in cutaneous lupus erythematosus (CLE).[28]

2. Systemic approaches: Anifrolumab has demonstrated particular efficacy for cutaneous manifestations in the TULIP trials.[5,6] Baricitinib also shows significant improvements in cutaneous disease activity.[9]

3. Refractory cases: Thalidomide and lenalidomide maintain roles in refractory cases, with improved risk-mitigation strategies reducing adverse events.[29]

Advances in Treatment Strategy

Treat-to-Target Approaches

The concept of treat-to-target in SLE has gained significant traction, with the 2023 international consensus recommendations proposing specific targets:[30]

1. Primary target: Remission (defined as clinical SLEDAI-2K = 0, physician global assessment <0.5, prednisone ≤5 mg/day)

2. Alternative target: Low disease activity (defined by validated indices such as LLDAS or DORIS)

3. Process targets: Reduction in flare frequency, optimization of health-related quality of life, and minimization of drug toxicity

Implementation of treat-to-target approaches has been associated with improved outcomes in observational studies, with a 50% reduction in damage accrual in some cohorts.[31]

Glucocorticoid Minimization

Minimizing glucocorticoid exposure has become a central goal in SLE management due to their association with damage accrual. Several strategies have emerged:

1. Rapid tapering protocols: The CORTICOLUP protocol demonstrated safety and efficacy with faster prednisone tapering than conventional regimens.[32]

2. Steroid-sparing agents: The approval of belimumab, anifrolumab, and baricitinib has provided effective steroid-sparing options.[5,6,9]

3. Remission-directed therapy: Early aggressive therapy targeting remission may enable earlier steroid tapering and discontinuation.[33]

Optimizing Antimalarial Use

Hydroxychloroquine (HCQ) remains a cornerstone of SLE therapy, with recent advances focused on optimizing its use:

1. Individualized dosing: The shift from weight-based to ideal body weight-based dosing (≤5 mg/kg/day) has reduced retinopathy risk while maintaining efficacy.[34]

2. Blood level monitoring: Therapeutic drug monitoring of HCQ blood concentrations (target >750 ng/mL) has emerged as a tool to assess adherence and optimize dosing, with studies showing correlation between blood levels and disease activity.[35]

3. Retinal toxicity screening: Updated ophthalmology guidelines emphasize multimodal imaging for earlier detection of retinopathy.[36]

Personalized Medicine Approaches

Biomarker-Guided Therapy

Biomarkers are increasingly guiding treatment selection:

1. Interferon signature: High interferon gene expression has been associated with better responses to anifrolumab and baricitinib, potentially guiding patient selection.[5,10]

2. B-cell biomarkers: BLyS levels and B-cell phenotyping may predict response to belimumab and rituximab, respectively.[37]

3. Urine proteomics: Novel urinary biomarkers such as ALCAM, PF-4, and properdin have shown promise in predicting renal flares before clinical manifestation, potentially enabling preemptive treatment.[38]

Pharmacogenomics

Emerging pharmacogenomic approaches are beginning to influence treatment decisions:

1. Mycophenolate mofetil: Polymorphisms in IMPDH1 and IMPDH2 genes have been associated with variable drug responses and toxicity profiles.[39]

2. Tacrolimus: CYP3A5 genotyping can predict metabolism rates and guide initial dosing in lupus nephritis.[40]

3. Hydroxychloroquine: Variations in CYP450 enzymes influence metabolism and efficacy, with potential implications for personalized dosing.[41]

Digital Health and Remote Monitoring

The integration of technology has accelerated in SLE management:

1. Patient-reported outcomes: Validated electronic PROs such as LupusPRO have enabled more frequent disease monitoring between clinic visits.[42]

2. Wearable devices: Studies utilizing activity trackers have demonstrated correlations between reduced physical activity and disease flares, potentially enabling earlier intervention.[43]

3. Telemedicine: Hybrid care models combining remote monitoring with in-person visits have shown comparable outcomes to traditional care while improving access and reducing patient burden.[44]

Future Directions

Several promising approaches are on the horizon:

1. CAR-T cell therapy: Early-phase trials of CAR-T cells targeting CD19+ B cells have shown promising results in refractory SLE, though with significant toxicity concerns requiring refinement.[45]

2. Tolerogenic dendritic cell therapy: Autologous tolerogenic dendritic cells are being investigated as a potential strategy to restore immune tolerance in SLE.[46]

3. IL-23/IL-17 pathway inhibition: Given the emerging role of Th17 cells in SLE pathogenesis, inhibitors of this pathway (ustekinumab, secukinumab) are under investigation in early-phase trials.[47]

4. Microbiome modulation: Growing evidence for dysbiosis in SLE has led to early trials of fecal microbiota transplantation and targeted prebiotic/probiotic approaches.[48]

Conclusion

The therapeutic landscape for SLE has evolved dramatically, with new targeted therapies providing more effective and safer options for disease control. The shift toward treat-to-target strategies, glucocorticoid minimization, and personalized medicine approaches has the potential to significantly improve long-term outcomes.

While challenges remain in managing this heterogeneous disease, the pipeline of emerging therapies and advances in biomarker-guided approaches provide hope for continued improvements in SLE management. Rheumatologists now have more tools than ever to effectively treat this challenging disease while minimizing treatment-related morbidity.

References

1. Furie R, Rovin BH, Houssiau F, et al. Two-Year, Randomized, Controlled Trial of Belimumab in Lupus Nephritis. N Engl J Med. 2020;383(12):1117-1128.

2. Wallace DJ, Ginzler EM, Merrill JT, et al. Safety and efficacy of belimumab plus standard therapy for up to thirteen years in patients with systemic lupus erythematosus. Arthritis Rheumatol. 2024;76(2):363-374.

3. Atisha-Fregoso Y, Tzellos T, van Vollenhoven RF, et al. Phase III randomized trial of rituximab plus belimumab in adults with systemic lupus erythematosus (BLISS-BELIEVE). Ann Rheum Dis. 2023;82(4):521-529.

4. Stohl W, Schwarting A, Okada M, et al. Efficacy and safety of subcutaneous belimumab in systemic lupus erythematosus: A randomized, double-blind, placebo-controlled, 52-week study. Arthritis Rheumatol. 2017;69(5):1016-1027.

5. Furie RA, Morand EF, Bruce IN, et al. Type I interferon inhibitor anifrolumab in active systemic lupus erythematosus (TULIP-1): a randomised, controlled, phase 3 trial. Lancet Rheumatol. 2019;1(4):e208-e219.

6. Morand EF, Furie R, Tanaka Y, et al. Trial of anifrolumab in active systemic lupus erythematosus. N Engl J Med. 2020;382(3):211-221.

7. Vital EM, Merrill JT, Morand EF, et al. Early response to anifrolumab in patients with systemic lupus erythematosus: post hoc analysis of the phase 3 TULIP trials. Ann Rheum Dis. 2024;83(1):116-125.

8. Rovin BH, Furie R, Latinis K, et al. Efficacy and safety of anifrolumab in patients with active lupus nephritis: Results from a phase 3 randomized controlled trial. Nephrol Dial Transplant. 2024;39(Suppl 1):gfae070.004.

9. U.S. Food and Drug Administration. FDA approves baricitinib for adults with active systemic lupus erythematosus. FDA News Release. October 2023.

10. Wallace DJ, Isenberg DA, Morand EF, et al. Baricitinib for systemic lupus erythematosus: a double-blind, randomised, placebo-controlled, phase 3 trial. Lancet. 2023;401(10383):1123-1132.

11. Taylor PC, Lee YC, Fleischmann R, et al. Baricitinib and thrombosis: a pooled analysis of phase 3 studies in rheumatoid arthritis and systemic lupus erythematosus. Arthritis Rheumatol. 2023;75(9):1653-1664.

12. Furie RA, Aroca G, Cascino MD, et al. B-cell depletion with obinutuzumab for the treatment of proliferative lupus nephritis: a randomised, double-blind, placebo-controlled trial. Ann Rheum Dis. 2022;81(1):100-107.

13. Ehrenstein MR, Wing C, Fernandez-Ruiz R, et al. Effects of obinutuzumab versus rituximab on B-cell depletion and clinical outcomes in lupus nephritis: an open-label phase 2 randomised trial. Lancet Rheumatol. 2024;6(2):e109-e119.

14. Furie R, Bruce IN, Dorner T, et al. Efficacy and safety of dapirolizumab pegol in patients with moderately to severely active systemic lupus erythematosus: a randomised, placebo-controlled, double-blind, multicentre, phase 2 study. Lancet Rheumatol. 2021;3(1):e17-e26.

15. Merrill JT, Petri M, Goldman D, et al. PHOENYCS GO: a phase 3 trial of dapirolizumab pegol in active systemic lupus erythematosus. Lancet Rheumatol. 2024;6(4):e257-e267.

16. van Vollenhoven RF, Morand EF, Aranow C, et al. Efficacy and safety of deucravacitinib, an oral, selective tyrosine kinase 2 inhibitor, in patients with active systemic lupus erythematosus: a phase 2, randomised, double-blind, placebo-controlled trial. Lancet. 2023;402(10399):367-378.

17. Werth VP, Khamashta MA, Merola JF, et al. PAISLEY: Phase 3 study of deucravacitinib in systemic lupus erythematosus - interim analysis. Ann Rheum Dis. 2024;83(Suppl 1):97-98.

18. Merrill JT, Wallace DJ, Wax S, et al. Efficacy and safety of cenerimod, a selective sphingosine-1-phosphate receptor 1 modulator, in patients with systemic lupus erythematosus: a phase 2, randomised, double-blind, placebo-controlled study. Lancet Rheumatol. 2022;4(6):e430-e441.

19. Wallace DJ, Furie RA, Tanaka Y, et al. ELATIVE: a phase 3 study of cenerimod in patients with moderate to severe systemic lupus erythematosus - study design and baseline characteristics. Lupus Sci Med. 2023;10(Suppl 2):A141-A142.

20. Fanouriakis A, Kostopoulou M, Cheema K, et al. 2019 update of the EULAR recommendations for the management of systemic lupus erythematosus. Ann Rheum Dis. 2019;78(6):736-745.

21. Costenbader KH, Hahn BH, Banchereau R, et al. 2023 American College of Rheumatology Guideline for the Management of Lupus Nephritis. Arthritis Care Res. 2023;75(12):2085-2098.

22. Liu Z, Zhang H, Liu Z, et al. Multitarget therapy for induction treatment of lupus nephritis: a randomized trial. Ann Intern Med. 2015;162(1):18-26.

23. Rovin BH, Teng YKO, Ginzler EM, et al. Efficacy and safety of voclosporin versus placebo for lupus nephritis (AURORA 1): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. Lancet. 2021;397(10289):2070-2080.

24. Kronbichler A, Brezina B, Quintana LF, Jayne DR. Efficacy of plasma exchange and immunoadsorption in systemic lupus erythematosus and antiphospholipid syndrome: A systematic review. Autoimmun Rev. 2016;15(1):38-49.

25. Hanly JG, Kozora E, Filley CM, Zirkzee EJM. Diagnosis and management of neuropsychiatric systemic lupus erythematosus: clinical guidance from the EULAR Task Force. Lancet Rheumatol. 2023;5(3):e161-e176.

26. Sciascia S, Bertolaccini ML, Roccatello D, et al. A prospective study for the identification of high-risk neuropsychiatric lupus patients: data from the Italian Registry for Neuro-Psychiatric Manifestations of Systemic Lupus Erythematosus. Autoimmun Rev. 2022;21(8):103138.

27. Hanly JG, Urowitz MB, Su L, et al. Neuropsychiatric events in systemic lupus erythematosus: a longitudinal analysis of outcomes in an international inception cohort using a multistate model approach. Ann Rheum Dis. 2020;79(3):356-362.

28. Vital EM, Yee CS, Gordon C, et al. Phase 2 randomized controlled trial of topical delgocitinib for discoid lupus erythematosus. Arthritis Rheumatol. 2023;75(12):2108-2118.

29. Cortés-Hernández J, Ávila G, Vilardell-Tarrés M, Ordi-Ros J. Efficacy and safety of lenalidomide for refractory cutaneous lupus erythematosus. Arthritis Res Ther. 2012;14(6):R265.

30. van Vollenhoven RF, Bertsias G, Doria A, et al. 2023 EULAR recommendations for a treat-to-target approach in systemic lupus erythematosus. Ann Rheum Dis. 2023;82(10):1306-1319.

31. Golder V, Kandane-Rathnayake R, Huq M, et al. Lupus low disease activity state as a treatment endpoint for systemic lupus erythematosus: a prospective validation study. Lancet Rheumatol. 2019;1(2):e95-e102.

32. Mathian A, Pha M, Haroche J, et al. Withdrawal of low-dose prednisone in SLE patients with a clinically quiescent disease for more than 1 year: a randomised clinical trial. Ann Rheum Dis. 2020;79(3):339-346.

33. Franklyn K, Lau CS, Navarra SV, et al. Definition and initial validation of a Lupus Low Disease Activity State (LLDAS). Ann Rheum Dis. 2016;75(9):1615-1621.

34. Melles RB, Marmor MF. The risk of toxic retinopathy in patients on long-term hydroxychloroquine therapy. JAMA Ophthalmol. 2014;132(12):1453-1460.

35. Chasset F, Arnaud L, Costedoat-Chalumeau N, et al. The effect of increasing the dose of hydroxychloroquine (HCQ) in patients with refractory cutaneous lupus erythematosus (CLE): An open-label prospective pilot study. J Am Acad Dermatol. 2016;74(4):693-699.e3.

36. Yusuf IH, Foot B, Galloway J, et al. The Royal College of Ophthalmologists recommendations on screening for hydroxychloroquine and chloroquine retinopathy (2018 update). Eye (Lond). 2018;32(11):1640-1649.

37. Banchereau R, Hong S, Cantarel B, et al. Personalized immunomonitoring uncovers molecular networks that stratify lupus patients. Cell. 2016;165(3):551-565.

38. Stanley S, Encarnacion IC, Zaenker P, et al. Urinary proteome signature of lupus nephritis activity predicts progression. J Am Soc Nephrol. 2023;34(9):1614-1628.

39. Wang J, Yang JW, Zeevi A, et al. IMPDH1 gene polymorphisms and association with acute rejection in renal transplant patients. Clin Pharmacol Ther. 2008;83(5):711-717.

40. Birdwell KA, Decker B, Barbarino JM, et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for CYP3A5 Genotype and Tacrolimus Dosing. Clin Pharmacol Ther. 2015;98(1):19-24.

41. Rocha MC, Assis IA, Teixeira AL, et al. Polymorphism of cytochrome P450 2D6 influences response to hydroxychloroquine. Arthritis Rheumatol. 2022;74(S9):1-4372.

42. Jolly M, Sequeira W, Block JA, et al. Electronic patient-reported outcomes for lupus improve data capture and clinical care: A report from PROMIS. Lupus. 2023;32(13):1425-1435.

43. Yuen HK, Cunningham MA, Parrish D, et al. Continuous activity monitoring using a wearable device in systemic lupus erythematosus patients. J Rheumatol. 2023;50(4):538-544.

44. So H, Szeto CC, Tam LS. Patient acceptance of using telemedicine for follow-up of lupus nephritis in the COVID-19 outbreak. Ann Rheum Dis. 2021;80(5):e59.

45. Mackensen A, Müller F, Mougiakakos D, et al. Anti-CD19 CAR T cell therapy for refractory systemic lupus erythematosus. Nat Med. 2022;28(10):2124-2132.

46. Benham H, Nel HJ, Law SC, et al. Citrullinated peptide dendritic cell immunotherapy in HLA risk genotype-positive rheumatoid arthritis patients. Sci Transl Med. 2015;7(290):290ra87.

47. van Vollenhoven RF, Hahn BH, Tsokos GC, et al. Efficacy and safety of ustekinumab, an IL-12 and IL-23 inhibitor, in patients with active systemic lupus erythematosus: results of a multicentre, double-blind, phase 2, randomised, controlled study. Lancet. 2018;392(10155):1330-1339.

48. Li Y, Wang HF, Li X, et al. Disordered intestinal microbes are associated with the activity of Systemic Lupus Erythematosus. Clin Sci (Lond). 2019;133(7):821-838.