间充质干细胞对再生障碍性贫血患者造血支持及T淋巴细胞分泌功能的影响

Effects of mesenchymal stem cells on hematopoietic support and secretory function of T lymphocytes in patients with aplastic anemia

背景:近年来,间充质干细胞在再生障碍性贫血中的作用受到广泛关注,但是其作用机制尚不清楚。目的:观察脐血间充质干细胞和骨髓间充质干细胞对再生障碍性贫血患者造血支持及T淋巴细胞分泌功能的影响。方法:收集48例再生障碍性贫血患者和48例健康者的骨髓和健康产妇脐血,采用流式细胞法分离骨髓间充质干细胞和脐血间充质干细胞;将2种间充质干细胞分别与脐血单个核细胞共培养,计数红系爆式集落形成单位和粒-巨噬细胞集落形成单位数目;将间充质干细胞与植物血凝素刺激的再生障碍性贫血患者T淋巴细胞共培养,ELISA检测T细胞分泌的白细胞介素2、白细胞介素4和γ-干扰素水平。结果与结论:(1)正常骨髓间充质干细胞和脐血间充质干细胞与脐血单个核细胞共培养后,其红系爆式集落形成单位和粒-巨噬细胞集落形成单位数目明显增多(P<0.05)。(2)再生障碍性贫血患者骨髓间充质干细胞与脐血单个核细胞共培养后,其刺激红系爆式集落形成单位和粒-巨噬细胞集落形成单位形成的能力明显减弱(P<0.05)。(3)与植物血凝素诱导的T细胞对照组相比,正常骨髓间充质干细胞共培养可明显抑制T细胞分泌白细胞介素2、白细胞介素4和γ-干扰素(P<0.05)。正常脐血干细胞共培养组也显示出了相似的抑制效果。(4)与正常骨髓间充质干细胞和脐血间充质干细胞共培养组相比,再生障碍性贫血患者骨髓间充质干细胞共培养组抑制T细胞分泌白细胞介素2、白细胞介素4和γ-干扰素的能力明显降低(P<0.05)。(5)结果表明再生障碍性贫血患者骨髓间充质干细胞存在功能缺陷,且对造血功能支持及对T细胞分泌功能的抑制作用明显弱于正常的骨髓间充质干细胞和脐血间充质干细胞,提示再生障碍性贫血患者间充质干细胞可能通过减弱其造血支持及抑制T细胞的功能来影响病理进程。

BACKGROUND： Recently, the role of mesenchymal stem cells 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 cells 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 cells using flow cytometry. Mesenchymal stem cells from the cord blood and bone marrow were respectively co-cultured with cord blood mononuclear cells to count burst forming units-erythroid and colony forming units-granulocyte/macrophage. Mesenchymal stem cells 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 cells co-cultured with cord blood mononuclear cells（P〈0.05）, but reduced remarkably in umbilical cord blood mesenchymal stem cells from aplastic anemia patients co-cultured with cord blood mononuclear cells（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 cells 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 cells. 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 cells from aplastic anemia patients（P〈0.05）. Aplastic anemia patients show some functional defects in their bone marrow mesenchymal stem cells that have a weaker inhibitory role than normal bone marrow or umbilical cord blood mesenchymal stem cells in the hematopoietic support and secretory function of T lymphocytes. These findings indicate that mesenchymal stem cells from aplastic anemia patients can influence the pathological progress through weakening hematopoietic support and secretory function of T lymphocytes.