483 Immunomodulatory Effects of Human Bone Marrow-derived Mesenchymal Stem Cells

INTRODUCTION: Human mesenchymal stem cells (MSCs) have great plasticity and the potential for therapeutic applications1 Due to the fact that MSCs could reduce the incidence severity of graft versus host disease2 We have investigated the immunologic properties of human marrow-derived MSCs. MATERIAL & METHODS: Bone marrow was obtained from healthy human donors of bone marrow to a related patient at Bone Marrow Transplantation Center, Nemazi Hospital, after obtaining approval of the Ethics Committee and Written informed consent. The Mononuclear cells derived over the Ficoll-Paque density-gradient, and plated in tissue cultures dish. The adherent cells expanded rapidly and maintained with periodic passages until a relatively homogeneous population was established. The MSCs were characterized by immunophenotyping and differentiation into osteoblast and adipocytes. Alloreactivity was studied after adding the MSCs to allogeneic lymphocytes in mixed lymphocyte reaction cultures. RESULTS: Flow cytometric analysis, and the differentiation potential into osteoblast and adipocytes showed that more than 90% of human MSCs were positive by specific markers and functional tests. Indeed, The MSCs expressed CD90, and CD73. But not CD80, CD40, and HLA class II. They also were negative for the hematopoietic markers CD34, and CD45. The MSCs do not induced proliferation of allogenic lymphocytes and suppressed them. CONCLUSION: The human marrow-derived MSCs do not elicit alloreactive lymphocyte proliferation. The results suggest that these cells have potentials for allogenic transplantation.