BACKGROUND:Recently, the role of mesenchymal stem cels in aplastic anemia has been widely explored. However, its underlying mechanism remains unclearly. OBJECTIVE: To study the effect of umbilical cord blood and bone marrow mesenchymal stem cels on hematopoietic support and secretory function of T lymphocytes in patients with aplastic anemia. METHODS: Cord blood and bone marrow samples from 48 cases of aplastic anemia and 48 healthy lying-in women to isolate mesenchymal stem cels using flow cytometry. Mesenchymal stem cels from the cord blood and bone marrow were respectively co-cultured with cord blood mononuclear cels to count burst forming units-erythroid and colony forming units-granulocyte/macrophage. Mesenchymal stem cels were co-cultured with T lymphocytes from aplastic anemia patients undergoing phytohemagglutinin stimulation, and ELISA was used to detect interleukin-2, interleukin-4 and interferon-γ levels secreted from T lymphocytes. RESULTS AND CONCLUSION:The number of burst forming units-erythroid and colony forming units-granulocyte/macrophage significantly increased in normal bone marrow or umbilical cord blood mesenchymal stem cels co-cultured with cord blood mononuclear cels (P < 0.05), but reduced remarkably in umbilical cord blood mesenchymal stem cels from aplastic anemia patients co-cultured with cord blood mononuclear cels (P < 0.05). Levels of interleukin-2, interleukin-4 and interferon-γ from T lymphocytes were inhibited significantly after co-culture with normal bone marrow mesenchymal stem cels compared with phytohemagglutinin-induced T lymphocytes (P < 0.05). There was a similar inhibitory effect after co-culture with normal umbilical cord blood mesenchymal stem cels. There was a significantly reduction in the capacity of inhibiting interleukin-2, interleukin-4 and interferon-γ levels from T lymphocytes after co-culture with bone marrow mesenchymal stem cels from aplastic anemia patients (P < 0.05). Aplastic anemia patients show some functional defects in their bone marrow mesenchymal stem cels that have a weaker inhibitory role than normal bone marrow or umbilical cord blood mesenchymal stem cels in the hematopoietic support and secretory function of T lymphocytes. These findings indicate that mesenchymal stem cels from aplastic anemia patients can influence the pathological progress through weakening hematopoietic support and secretory function of T lymphocytes. Cite this article:Li GC, Song YP, Zhang YJ, Li G, Wang H, Xie J.Effects of mesenchymal stem cels on hematopoietic support and secretory function of T lymphocytes in patients with aplastic anemia. Zhongguo Zuzhi Gongcheng Yanjiu. 2016;20(1):107-112.