Four cases of red blood cell aplasia in association with the use of mycophenolate mofetil in renal transplant patients.

Mycophenolate mofetil (MMF) is one of the new immunosuppressive drugs used in renal transplantation. MMF inhibits the de novo purine synthesis. Since this purine synthesis in lymphocytes entirely depends on the de novo pathway, MMF is considered to cause a selective inhibition of T- and B lymphocytes. Recently, 4 transplant patients out of 30 developed a severe anemia in the early post-transplantation period. Their immediate post-transplantation immunosuppression consisted of corticosteroids, cyclosporine and MMF. They all received anti-T-lymphocyte globulin (ATG) as induction treatment or because of rejection. In all 4 patients, iron supplementation and a treatment with erythropoietin were started. Blood loss, deficiencies, hemolysis, drug interactions or viral infections were excluded as causes of the anemia. Bone marrow biopsies were carried out, showing pure red cell aplasia that was ascribed to the use of MMF. Cessation or reduction of MMF was followed by a hematological improvement after 5-9 days. We hypothesized that MMF has a broader antiproliferative effect than its proposed lymphocyte-specific effect.