Immunohistochemical changes on dendritic cells in microenvironment of thymus in patients with myasthenia gravis / 中华神经科杂志

ABSTRACT

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.