Warm autoimmune hemolytic anemia and hemophagocytic lymphohistiocytosis/macrophage activation syndrome occurring after COVID19 infection and administration of Casirivimab + Imdevimab (COVID19 monoclonal antibody)

Abstract

Key Clinical MessageWarm Autoimmune Hemolytic Anemia (WAHA) is the most common form of autoimmune hemolysis and there is a growing body of evidence of an association between SARS‐CoV‐2 infection, WAHA and a hyperinflammatory state, including hemophagocytic lymphohistiocytosis/macrophage activation syndrome. However, there is no literature to date of WAHA or hyperinflammatory state following administration of anti‐SARS‐CoV‐2 monoclonal antibody treatment. This report documents a case of a patient with history of WAHA who developed brisk hemolysis and a hyperinflammatory state consistent with hemophagocytic lymphohistiocytosis/macrophage activation syndrome after COVID‐19 infection and treatment with an anti‐SARS‐CoV‐2 monoclonal antibody. He was successfully treated with multimodal treatment involving steroids, intravenous immunoglobulins, rituximab, anakinra, and vincristine with resolution of the hemolysis.