Autoimmune Hemolytic Anemia Following Intravenous Immunoglobulin in Kawasaki Disease.

Autoimmune hemolytic anemia (AIHA) is an uncommon but recognized complication of intravenous immunoglobulin (IVIG) therapy in Kawasaki disease (KD). The mechanism is thought to involve passive transfer of donor isohemagglutinins that bind to recipient red blood cell (RBC) antigens, causing immune-mediated hemolysis. We describe four pediatric cases of IVIG-induced AIHA following treatment for KD. We retrospectively reviewed four KD patients who developed hemolytic anemia temporally associated with IVIG administration. Clinical data included age, blood type, transfusion requirement, and outcomes. All four patients were non-O blood types. Hemolysis developed within days of IVIG infusion, confirmed by a positive direct antiglobulin test. Two patients required red blood cell transfusions for symptomatic anemia. The lowest recorded hemoglobin levels ranged from 6.6 to 7.9 g/dL. None required corticosteroids or additional immunosuppression. All patients achieved full recovery with iron and folate supplementation. No coronary aneurysms or long-term complications were observed. IVIG-induced AIHA is a rare but clinically significant complication of KD therapy, particularly in non-O blood group patients. Routine post-infusion hemoglobin monitoring and early recognition of anemia are essential. Supportive management alone is typically sufficient, and prognosis remains excellent when the condition is promptly identified and managed.