Mesalazine-associated severe aplastic anemia successfully treated with antithymocyte globulin, cyclosporine and granulocyte colony-stimulating factor.

A 20-year-old male with ulcerative colitis complicated by mesalazine-associated severe aplastic anemia is described. The patient developed aplastic anemia four months after the start of mesalazine therapy. He was treated with antithymocyte globulin, cyclosporine, and granulocyte colony-stimulating factor (G-CSF) and responded well. Hematological complications of mesalazine are rare, but if bone marrow suppression is detected, immediate cessation of the drug and intensive immunosuppressive treatment with G-CSF should be considered.