Study on the immunoregulation of mesenchymal stem cells from patients with aplastic anemia

WU Yan; YU Jie; ZHANG Lei; LUO Qing; XIAO Jian-wen; LIU Xiao-mei; XIAN Ying; DAI Bi-tao; XU You-hua; SU Yong-chun

Abstract：Objective To study the immunosuppressive activity of MSC from controls or patients with AA in vitro. Methods Bone marrow samples were collected from patients with A A at diagnosis[n= 24, 12 from severe aplastic ane-mia(SAA) , 12 from chronic aplastic anemia(CAA)]and the patients whose findings of bone marrow aspiration were nor-mal as the controls (n= 11). MSCs from bone marrow samples were isolated, cultured and expanded. Morphology, pro-liferative activity and colony forming unit-fibroblast (CFU-F) were measured and analyzed. MSC were assayed for the activity of lymphocytes suppression by mixed lymphocyte reaction (MLR). The hepatocyte growth factor and transforming growth factor-β1 mRNA expression were detected by RT-PCR. HGF and TGF-β1 concentrations of MSC were tested by enzyme-linked immunosorbent assay (ELISA). Results (l) The culture cells from the patients with AA presented a typical fibroblast-like morphology. The number of CFU-F from the patients with AA (15.70±5.78) was fewer than that from the controls (22.33±5.33) , t = -2.74, P < 0.05. (2) The inhibition ratio of MSC from patients with AA[(49.78± 20.36)% ]was significantly lower than that from the controls[(76.42±8.80)% ], t=3.48, P < 0.01. (3) The level of TGF-βl mRNA expression in MSC from patients with AA was significantly lower than the controls, t = -3.34,P < 0.01, and the level of HGF mRNA expression in MSC from patients with AA was significantly lower than the controls, t = -2.54, P < 0.05. (4) The concentration of TGF-β1 in MSC supernatants from the patients with AA [(415.09±108.10) pg/ml] was significantly lower than the con-trols [(632.40±126.90) pg/ml], t =-2.48, P < 0.05; the concentration of HGF in MSC supernatants from the patients with AA [(340.72±40.44) pg/ml] was significantly lower than that from the controls [(521.56±36.72)pg/ml], t = -2.46, P < 0.05. All these differences were of statistical significance. Conclusion The suppressive effect of MSC from patients with AA in vitro is significant-ly decreased. Its mechanism may be related to the decreased proliferative capacity, TGF-β1, HGF mRNA expression level in MSC and TGF-β1, HGF release activity.