Posttransplant Autoimmune Hemolytic Anemia with Anti-D Specificity Successfully Treated with Daratumumab: A Case Report.

Introduction: Autoimmune hemolytic anemia (AIHA) occurs in 0.7-5.6% of patients undergoing hematopoietic stem cell transplantation, especially from unrelated or haploidentical donor or after lympho-depleted transplant; the majority of cases are represented by warm AIHA, occurring in a full donor chimerism setting. Standard treatments (corticosteroids, intravenous immunoglobulin, splenectomy, rituximab, cyclophosphamide, plasma exchange) lead to lower response rates than those reported in primary AIHA. Daratumumab use has been proposed in many autoimmune conditions (immune thrombocytopenic purpura, aplastic anemia, thrombotic thrombocytopenic purpura, systemic lupus erythematosus, multiple sclerosis), but only few reports have been published on its use for post-HSCT AIHA, mainly in pediatric patients. Case Presentation: We report the successful use of daratumumab in a 68-year-old patient, suffering from post-HSCT AIHA. Five months after Rh-mismatched HSCT, the patient was diagnosed with anti-D AIHA. After first-line treatment (oral prednisone, rituximab, and plasma exchange) failure, being still transfusion-dependent with symptomatic anemia, he underwent treatment with daratumumab, achieving both clinical and laboratory responses. Discussion: Daratumumab may represent a safe and effective alternative to conventional immunosuppressive therapy, and it deserves further investigations.