AUTOIMMUNE HEMOLYTIC-ANEMIA DURING ALPHA-INTERFERON TREATMENT IN 9 PATIENTS WITH HEMATOLOGICAL-DISEASES

Background. A number of side effects have been observed in patients tr eated for hematological diseases with alpha-interferon (IFN). In sever al cases side effects consisted of immunological disorders. Autoimmune hemolytic anemia (AIHA) is the most typical example of an IFN-induced immune-mediated complication. Case series. In 10 years we observed 9 patients with various hematological disorders who developed AIHA durin g IFN treatment. The interval between the start of IFN treatment and t he onset of acute hemolysis suggests a dual pattern of occurrence: (1) early onset (interval 1 to 21 days), seen in patients who had anti-RB C antibodies before IFN treatment; (2) late onset (interval 3-38 month s), in patients with no history of anti-RBC antibodies at the start of treatment. Discontinuation of IFN, often associated with prednisone t reatment, caused prompt hematological recovery in all cases; anti-eryt hrocyte antibodies persisted in the first group of patients and disapp eared in the second. Conclusions. In rare cases IFN may cause AIHA. Th e immunological derangement caused by IFN seems to act at two differen t levels: enhanced destruction of antibody-coated RBCs and induction o f autoreactive B-cells. As for the possibility of other preexisting im munological disorders, AIHA (even latent) is a contraindication to IFN treatment. Patients treated with IFN need accurate monitoring to guar d against for the development of autoimmune disorders.