Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune diseases directed against hematopoietic cells, including autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), pure red cell aplasia (PRCA), and immune neutropenia. CLL represents the diagnosis in up to 15% of the patients with AIHA, and in 50% of the patients with AIHA secondary to malignancy. ITP occurs in 2% and PRCA in about 1% of all CLL patients. Prednisone is the first-line treatment for immune cytopenia related to CLL. About 60% of patients relapse when treatment is stopped therefore splenectomy, intravenous immunoglobulin, or cyclosporine are reasonable second-line treatments. Although the data on pathophysiology are very limited, it appears that the autoimmune mechanisms are related to the activity of the leukemic B lymphocytes that act as aberrant antigen-presenting cells, and are effective in processing and presenting proteins derived from red cells or platelets to auto-reactive TH cells. TH cells specific for certain auto-antigens escape from control mechanisms and when activated may initiate auto-immune disease. Patients with AIHA secondary to CLL should not receive fludarabine because there is an increased frequency of severe and fatal AIHA in patients treated with purine nucleoside analogues. Patients who are more immunosuppressed due to several previous treatments are at higher risk for developing this auto-immune complication.
Chronic lymphocytic leukemia; autoimmune hemolytic anemia; blood transfusion; immune thrombocytopenic purpura; pure red cell aplasia
