Severe autoimmune thrombocytopenic purpura during interferon-alpha therapy for chronic myelogenous leukemia.

Interferon (IFN)-α is a leukocyte-derived cytokine and is used to treat several hematopoietic malignancies. The most common adverse effects of IFN-α are flu-like symptoms and usually insignificant. However, adverse effects due to autoimmune mechanisms are often hazardous and irreversible, although their frequency is low. In the present report, we describe a 55-year-old female with chronic myelogenous leukemia who developed severe autoimmune thrombocytopenia during IFN-α therapy. The lowest platelet count was 6 × 109/l with severe hemorrhagic tendency. The present report strongly suggests the clinical importance of autoimmune thrombocytopenia as an adverse effect of IFN-α.