Hildner K, Finotto S, Becker C, Schlaak J, Schirmacher P, Galle P R, Märker-Hermann E, Neurath M F
Laboratory of Immunology, I. Medical Clinic, University of Mainz, Mainz, Germany.
Clin Exp Immunol. 1999 Oct;118(1):137-46. doi: 10.1046/j.1365-2249.1999.01022.x.
Methotrexate (MTX) is an effective immunosuppressive agent in various chronic inflammatory diseases such as rheumatoid arthritis (RA). However, its mechanisms of action are only partially understood. In this study, we assessed the effects of MTX on the differentiation of peripheral blood (PB) CD4+CD45RA 'naive' and CD4+CD45RO 'memory' T cells from healthy controls and patients with RA. Accordingly, purified T cells were primed and restimulated in vitro via the T cell receptor (TCR) in the presence of IL-2 to generate effector T cells secreting large amounts of Th1 and Th2 cytokines. We observed that low doses of MTX strongly suppress TNF and to a lesser extent interferon-gamma (IFN-gamma) production by T cells from both healthy donors and RA patients when present during T cell priming via the TCR. Similar data were obtained for TCR-primed synovial fluid mononuclear cells in RA. In contrast, production of IL-4 by TCR-primed CD45RA T cells was significantly increased upon MTX treatment. Interestingly, MTX did not enhance IL-4 production when present during restimulation of effector CD45RO T cells, although it still suppressed TNF production. The results indicate that MTX effects depend on the stage of T cell activation and identify TNF production by TCR-primed T lymphocytes as a target for low-dose MTX treatment in RA. These findings could explain the delayed clinical effects of MTX and may contribute to its potent anti-inflammatory and immunoregulatory properties.
甲氨蝶呤（MTX）是一种在类风湿关节炎（RA）等多种慢性炎症性疾病中有效的免疫抑制剂。然而，其作用机制仅得到部分了解。在本研究中，我们评估了MTX对健康对照者和RA患者外周血（PB）CD4 + CD45RA“初始”和CD4 + CD45RO“记忆”T细胞分化的影响。相应地，纯化的T细胞在IL-2存在的情况下通过T细胞受体（TCR）在体外进行致敏和再刺激，以产生分泌大量Th1和Th2细胞因子的效应T细胞。我们观察到，当在通过TCR进行T细胞致敏期间存在低剂量MTX时，它能强烈抑制健康供体和RA患者T细胞产生TNF，对干扰素-γ（IFN-γ）的产生抑制作用较小。对于RA中经TCR致敏的滑液单核细胞也获得了类似的数据。相比之下，经MTX处理后，经TCR致敏的CD45RA T细胞产生的IL-4显著增加。有趣的是，当在效应CD45RO T细胞再刺激期间存在MTX时，它不会增强IL-4的产生，尽管它仍然抑制TNF的产生。结果表明，MTX的作用取决于T细胞激活的阶段，并确定经TCR致敏的T淋巴细胞产生TNF是RA中低剂量MTX治疗的靶点。这些发现可以解释MTX的临床疗效延迟，并可能有助于其强大的抗炎和免疫调节特性。
