Pure red cell aplasia (PRCA) is characterized by a selective marrow aplasia of the erythroid compartment. Immunosuppressive therapy achieves good results in about 25% of cases, but relapses are frequent. Autologous or allogeneic haematopoietic stem cell transplantation (HSCT) may be valuable in selected patients. Here, we report details of a 29-year-old woman treated successfully by donor lymphocyte infusions (DLIs) following allogeneic HSCT for acquired refractory relapsed PRCA. The nonmyeloablative conditioning regimen consisted of cyclophosphamide 60 mg/kg/day for 2 days and fludarabine 30 mg/m(2) daily for 4 days. Haematopoiesis was still completely 'recipient' 1 month after allo-HSCT, but progressed to full donor engraftment after three doses of 'escalating' DLI. The possible role of a graft-versus-autoimmunity effect induced by allogeneic HSCT followed by DLI infusions in the treatment of the disease is discussed.