Post‑COVID‑19 Autoimmune Hemolytic Anemia in a Patient With Multiple Myeloma Receiving Daratumumab: A Case Report and Review of Immune Mechanisms

Abstract

Autoimmune hemolytic anemia is an uncommon immune‑mediated disorder characterized by the production of autoantibodies directed against erythrocyte antigens, leading to premature red blood cell destruction. Viral infections have long been recognized as potential triggers of autoimmune cytopenias. Since the emergence of SARS‑CoV‑2, increasing evidence has suggested that coronavirus disease 2019 may induce autoimmune phenomena through immune dysregulation, molecular mimicry, complement activation, and sustained inflammatory responses. Patients with multiple myeloma represent a particularly vulnerable population because of disease‑related immunoparesis and therapy‑associated immune modulation. We report the case of an 83‑year‑old man with IgG‑lambda multiple myeloma receiving daratumumab‑based therapy who developed symptomatic autoimmune hemolytic anemia shortly after a mild SARS‑CoV‑2 infection. Laboratory investigation revealed hemoglobin of 7.2 g/dL, lactate dehydrogenase of 290 U/L, indirect bilirubin of 1.5 mg/dL, reticulocytes of 2.5%, and a positive direct antiglobulin test. Corticosteroid therapy resulted in rapid hematologic improvement, although temporary steroid dependence occurred. This report highlights the complex interaction between viral infection, immune dysregulation related to hematologic malignancy, and immunomodulatory therapy. Recognition of autoimmune hemolytic anemia as a possible complication of SARS‑CoV‑2 infection in patients with multiple myeloma is essential for prompt diagnosis and appropriate management.