Thrombocytopenia and Anemia with Anti-c-Mpl antibodies Effectively Treated with Cyclosporine in a Patient with Rheumatoid Arthritis and Chronic Renal Failure.

A 61-year-old woman with rheumatoid arthritis who was undergoing hemodialysis for end-stage renal failure was transferred to our hospital due to severe thrombocytopenia and anemia. A bone marrow biopsy showed the complete absence of megakaryocytes and erythroblasts. Cyclosporine treatment resulted in the improvement of her megakaryocyte and erythroblast levels, and a decrease in her serum level of anti-c-Mpl (thrombopoietin receptor) antibodies. After this initial improvement, her anemia progressively worsened, despite the continuous administration of immunosuppressive therapy with cyclosporine. Her platelet and leukocyte counts remained stable. This is the first report of a probable case of anti-c-Mpl antibody-associated pure red cell aplasia and acquired amegakaryocytic thrombocytopenic purpura.