间质干细胞对SLE患者外周血T细胞的免疫抑制作用

Immunosuppressive effects of mesenchymal stem cells on peripheral blood T lymphocytes from patients with systemic lupus erythematosus

目的探讨体外骨髓间质干细胞（MSC）对SLE患者外周血T淋巴细胞（T细胞）的免疫调节作用及可能机制。方法分离培养健康人骨髓MSC并鉴定其纯度，分离SLE患者外周血T细胞，在植物血凝素（PHA）刺激下，用不同比例的MSC与T细胞作用。分为T细胞、T细胞＋MSC1（T：MSC，=1：0．02）、T细胞＋MSC2（T：MSC2：1：0．2）3组。采用MTT法检测T细胞增殖，流式细胞仪检测T细胞CD152^＋和CD28^＋的表达，实时PCR测定IFN-γ和IL-6 mRNA的表达水平。结果MSC可明显抑制SLE患者T细胞增殖。T细胞增殖在T细胞组A值为0．765±0．056，T细胞＋MSCl组为0．484±0．032，T细胞＋MSC2组为0．308±0．025，与对照组相比，A值均明显降低（P〈0．05），T细胞＋MSC1组和T细胞＋MSC2组之间差异也有统计学意义（P〈0．05）。T细胞组CD28^＋细胞百分比为（74．73±3．74）％，T细胞＋MSC，组为（60．39±3．92）％，T细胞＋MSC2组为（45．05±3．46）％，与对照组相比均明显降低（P〈0．05），T细胞＋MSC1组和T细胞＋MSC2组之间差异也有统计学意义（P〈0．05）。MSC对T细胞CD152^＋表达无显著影响。MSC明显抑制T细胞IFN-γ、IL-6 mRNA表达（P〈0．05），并且随着MSC数量的增加，抑制作用增强。结论MSC对SLE患者T细胞有免疫抑制作用，可能与抑制T细胞增殖、抑制T细胞CD28^＋表达和抑制T细胞IFN-γ、IL-6 mRNA表达有关。

Objective To investigate the immunoregulatory effects of mesenchymal stem cells （MSCs） on peripheral blood T lymphocytes from patients with systemic lupus erythematosus （SLE） in vitro and their potential mechanism. Methods MSCs were isolated from the bone marrow of 3 healthy human volunteers, cultivated and identified. Under phytohemagglutinin （PHA） stimulating, peripheral blood T lymphocytes from 8 patients with SLE were treated with MSCs with the T lymphocyte/MSC ratio being 50：1 in group B and 5 ： 1 in group C or without MSCs （group A）. MTT assay was used to detect the proliferation of T lymphocytes, flow cytometry to analyze the expressions of surface markers CD152 and CD28 on T lymphocytes, and real time PCR to measure the mRNA expressions of interleukin-6 and interferon-γ in the T lymphocytes. Results MSCs could markedly inhibit the proliferation of T lymphocytes. The proliferation of T lymphocytes expressed as absorbance value at 570 nm was 0.484 ± 0.032 in group B, 0.308 ± 0.025 in group C, significantly lower than that in group A （0.765 ± 0.036, both P 〈 0.05）, and significant difference was also observed between group C and B （P 〈 0.05）. In the case of the percentage of CD28 positive T lymphocytes, group B and C were significantly lower than group A （60.39% ± 3.92% and 45.05% ± 3.46% vs 74.73% ± 3.74%,both P 〈 0.05）, and group B significantly differed from group C （P 〈 0.05）. MSCs had no obvious effect on the expression of CD152 on T lymphocytes, but significantly suppressed the rnRNA expression of interleukin-6 and interferon-7 （both P 〈 0.05）, and the suppressive effect was enhanced with the increase in MSC count. Conclusions MSCs exert an immunosuppressive effect on T lymphocytes from patients with SLE, likely through inhibiting the proliferation, CD28 expression, interleukin-6 and interferon-γ mRNA expression of T lymphocytes.