Inoue M, Okumura M, Miyoshi S, Shiono H, Fukuhara K, Kadota Y, Shirakura R, Matsuda H
First Department of Surgery, Division of Organ Transplantation Biomedical Research Centre, Osaka University Medical School, Osaka, Japan.
Clin Exp Immunol. 1999 Jul;117(1):1-7. doi: 10.1046/j.1365-2249.1999.00933.x.
A human thymoma is a neoplasm derived from the thymic epithelial cell, and is well known for its association with autoimmune diseases, especially myasthenia gravis. The neoplastic epithelial cells of thymoma clearly retain thymic epithelial functions, but the development of T cells in thymoma is somewhat impaired. In this study, we quantified by flow cytometry the in vitro expression of MHC molecules on neoplastic epithelial cells precultured with IFN-gamma. While MHC class I expression was comparable with that on normal thymic epithelial cells, the level of MHC class II molecules on neoplastic epithelial cells was lower than in controls, and also varied greatly from case to case. Additionally, there was a significant positive correlation between the expression level of MHC class II and the proportion of mature CD3+ cells in the CD4+CD8- subset. Thus, accumulation of CD3-CD4+CD8- cells in thymoma may result from impaired expression of the MHC class II molecules, suggesting that the function of the neoplastic epithelial cells might determine the maturation and the positively selected repertoire of T cells in thymomas.
人类胸腺瘤是一种起源于胸腺上皮细胞的肿瘤，因其与自身免疫性疾病，尤其是重症肌无力的关联而闻名。胸腺瘤的肿瘤上皮细胞明显保留胸腺上皮功能，但胸腺瘤中T细胞的发育有所受损。在本研究中，我们通过流式细胞术对用γ干扰素预培养的肿瘤上皮细胞上MHC分子的体外表达进行了定量。虽然MHC I类分子的表达与正常胸腺上皮细胞相当，但肿瘤上皮细胞上MHC II类分子的水平低于对照组，并且在不同病例之间也有很大差异。此外，MHC II类分子的表达水平与CD4+CD8-亚群中成熟CD3+细胞的比例之间存在显著正相关。因此，胸腺瘤中CD3-CD4+CD8-细胞的积累可能是由于MHC II类分子表达受损所致，这表明肿瘤上皮细胞的功能可能决定胸腺瘤中T细胞的成熟和阳性选择的库。
