Abstract: Objective: To explore the effect of plasma exchange on graft-versus-host disease (GVHD) and pure redcell aplasia (PRCA) after allogeneic peripheral blood stem cell transplantation (Allo-PBSCT). Methods: Ten patients whohad undergone Allo-PBSCT between September 2002 and January 2006 were treated with plasma exchange plus immuno-suppressive drugs to treat refractory GVHD and PRCA. BU/CY regimen was administered in patients with acute myeloidleukemia and chronic myeloid leukemia, and TBI/CY regimen was administered in patients with acute lymphoblasticleukemia. In the transfusion the median count of mononuclear cells was 8.1× 108/kg and the median count of CD34+ cellswas 9.2× 106/kg. Cyclosporine A, mycophenolate mofetil and short course methotrexate were administered to preventGVHD. Plasma exchange was performed two to four times on each patient with 2500-3000 ml replacement fluid consistingof fresh frozen plasma, each time using Baxter CS 3000 Plus Blood Cell Separators. Results: Re -establishment ofhaematogenesis was successfully achieved in all of the patients. Full donor chimeras were observed in all of the patientsby detecting short tandem repeats with fluorescently labeled polymerase chain reaction. Of the 7 patients with GVHD, thelevel of interleukin-2 receptor, interleukin-6, interleukin-8 and tumor necrosis factor-αwere lower after plasma exchangethan before plasma exchange (P<0.05). Clinical symptoms of GVHD in 6 patients were successfully controlled and the pa-tients were alive and disease-free with a median follow-up of 39 (11-50) months. One patient died of chronic GVHD 14months after transplantation. The 3 patients with PRCA gradually had hemoglobin levels restored to the normal range, andtheir ABO blood type became the donor's blood type. Conclusion: Plasma exchange combined with immunosuppressivedrugs is effective in the treatment of GVHD and PRCA after Allo-PBSCT.