重症肌无力患者胸腺微环境内树突状细胞的免疫组织化学变化

目的 探讨重症肌无力（MG）胸腺微环境内树突状细胞、淋巴细胞和上皮细胞的免疫组织学变化。方法 （1）25例MG病人（胸腺滤泡性增生者13例，无增生者12例）、7例先天性心脏病和1例新生儿胸腺组织，常规石蜡包埋切片，HE染色，光镜观察。（2）免疫化学标记S－100、CD1a、CD4、CD8、CD20、CD45RO、细胞角蛋白（CKPan)、上皮细胞膜抗原（EMA）和癌胚抗原（CEA），光镜观察，对其中S－100，CD1a阳性的树突状细胞半定量计数，t检验，统计分析。结果 （1）在胸腺淋巴滤泡性增生组和非增生组，胸腺单位面积内（100m^2)表达S－100阳性的树突状细胞数是23．5和47.5,CD1a为2．1和3．8，两组t检验，P＜0．05）。（2）胸腺质皮细胞和淋巴滤泡性增生的髓质分别表达CD1a、CD8和CD45RO，胸腺小体、血管周围淋巴细胞极少表达CD1a，胸腺髓质和生发中心内淋巴细胞表达CD20。（3）胸腺被膜下、皮质、胸腺小体和髓质内有表达CKPan的上皮细胞，但EMA和CEA阴性。结论 （1）MG时胸腺髓质无论有无淋巴滤泡性增生，都表达多量抑制T细胞和CD20淋巴细胞；生发中心内有多量表达CD20和少量CD8细胞。（2）MG时胸腺微环境内这些抗体的表达和树突状细胞数量的变化，将影响T、B淋巴细胞增生和淋巴滤泡形成；胸腺内树突状细胞与其基质细胞在MG的发病中起重要作用。

Immunohistochemical changes on dendritic cells in microenvironment of thymus in patients with myasthenia gravis

Objective To investigate the microenvironment of the thymus on lymphocytes, dendritic cells and epithelial cells were studied in patients with myasthenia gravis.Methods (1) The thymus specimens of 25 cases were examined using light microscopy,in which 10 were males,15 females with an average age of 31 years old. The lymphoid tissue with proliferation was in 13 cases, without proliferation in 12 cases. Additionally, 7 cases had congenital heart disease (the average age was 27 years old) and the thymus of an infant (1 case) was examined. (2) Immunohistochemical staining for CD1a?CD4?CD8?CD20?CD45RO?S 100?CKPan and EMA were performed onto the specimens. Some of them with positive dendritic cells on S 100 and CD1a were counted. Results (1) It showed that the positive cells of CD1a located at cortical areas of the thymus with or without lymphoid tissue proliferation in MG and non MG cases. However, there were some positive cells in the medulla, Hassall corpuscles and the vascular space areas of the thymus. (2) The CD4 staining was negative. (3) The expression of CD8 and CD45RO was expressed in the medulla, peripheral areas of the Hassall corpuscles and vascular space of the thymus. (4) CD20 was expressed in the medulla and the germinal central areas. (5) The expression of S 100 for dendritic cells were 23.5 and 47.5 per 100 mm 2 in both having medullary follicular hyperplasia and no follicular hyperplasia groups. The CD1a were 2.1, 3.8 per 100 mm 2, respectively. The statistic was significant as compared with both groups with or without proliferation of thymus medulla. (6) The expression of CK was located in the cortex, medulla and Hassall corpuscles. But EMA, CEA were negative. Conclusions (1) There were expressions of suppressive T cells (CD8) and B lymphocytes (CD20) with or without the thymus medullary lymphoid follicular hyperplasia. (2) The changes of numerous quantity of the dendritic cells on the thymus were displayed which showed a relation to the proliferation of T, B lymphocytes and the formation of germinal central of thymus.It suggested that the dendritic cells and the other stromal cells of the thymus may serve as an important role in MG occurrence.