Paroxysmal nocturnal hemoglobinuria (PNH) and aplastic anemia are associated either as a PNH-aplasia syndrome or the emergence of glycosylphosphatidylinositol-(GPI)deficient blood cells in patients with severe aplastic anemia (SAA). It could be demonstrated that SAA patients with GPI-deficient cells in comparison to those without have a worse response to classical immunosuppressive therapy. Therefore, we treated a female PNH patient with severe thrombocytopenia, anemia and granulopenia with G-CSF and cyclosporine. Within 8 weeks, a trilineage response of hematopoiesis was observed. In addition, the proportion of normal to GPI-deficient granulocytes and monocytes increased significantly.