Abstract: Two patients with severe aplastic anemia(SAA)treated by syngeneic BMTand allogeneic BMTplus peripheral blood stem cell transplantation(PBSCT)respectively were reported. The patient suffering from SAA Ⅱ had an identical twin brother. He received brother's marrow transfusion(1.5×10⁸/kg)alone and had sustained recovery of PBcounts and marrow haemopoiesis.He is alive and works normally more than 4 years. Another patient with very SAA(vSAA)and had an HLAfull matched(HLAtyping, cross matched MLCand DRB PCR/printing)brother as donor. He had received previous transfusion 12 times. He was administered four daily doses of Cy(50 mg/kg×4, total 200 mg/kg)alternating with three doses of ATG(25 mg/kg×3, total 75 mg/kg)followed by a HLAidentical marrow graft(2.7×10⁸ /kg,0 d)and peripheral blood stem cell(PBSC)transfusion(CD34⁺cells 3.85×10⁵/kg,+1 d). Methotrexate(MTX)and cyclosporine A(CSP)were administered to prevent GvGH. His PMNs increased more than 0.2×10⁹/Lsince +14 days and RBCantigen from MNbecame NN(donor′s source)at +61 d. However,he was complicated with systemic MRSAinfection since +12 d and followed by abscess of thoracic vertebra.The managements for abcess were effective and the patient is recovering. The article also discussed some problems with treatment of SAA.

Key words: haemopoietic stem cell transplantation, syngeneic, allogeneic