Autoimmune myelofibrosis associated with autoimmune hemolytic anemia successfully treated with ruxolitinib

Abstract A 55-year-old man suffered from dyspnea, general malaise, and jaundice. His laboratory date showed pancytopenia and hemolytic anemia, and computed tomography showed splenomegaly. Bone marrow examination revealed myelofibrosis (MF)-1. The hemolytic anemia was diagnosed as IgM autoimmune hemolytic anemia (AIHA) with negative direct and indirect Coombs test but positive IgM-direct antiglobulin test. We started ruxolitinib 20 mg, which improved not only bone marrow fibrosis, symptoms related to myeloproliferative neoplasms and splenomegaly, but also AIHA. AIHA may be associated with Autoimmune MF (AIMF), and cytokines such as transforming growth factor (TGF)-β are thought to be involved in such cases. This case suggests that ruxolitinib may improve the cytokine levels and may lead to the treatment of AIHA as well as AIMF.