Local immune response in endometrial carcinomas

Objective To determine whether Langerhans cells act as antigen-presenting cells in endometrial carcinomas and their related lesions. Samples Frozen endometrial samples were obtained from 13 women with normal menstrual cycles, 3 postmenopausal women, 11 women with hyperplasia (simple 4, complex 4 and atypical 3) and 32 women with endometrial carcinomas. Main outcome measures Langerhans cells (CD1), T lymphocytes (CD4 and CD8), B lymphocytes (CD22), natural killer (NK) cells (CD57) and HLA-DR were all quantitatively assessed in endometrial samples using immunohistochemical method. Results The numbers of Langerhans, CD4+, CD8+ and B cells were higher in the secretory phase than in the proliferative endometrium. The CD8+ cells appeared to be more plentiful than the CD4+ cells. When compared with the proliferative endometrium, the numbers of langerhans cells were higher in hyperplasias and carcinomas. Most of Langerhans cells were HLA-DR+, showing a strong correlation with CD4+ cells in carcinomas. This suggests that MHC class II antigen restricted lymphocytes in carcinomas are activated by HLA-DR+ Langerhans cells. However, epithelial expression of HLA-DR in carcinomas did not show on association with high numbers of langerhans and CD4+ cells. No correlation was observed between Langerhans cells and clinicopathologic features of carcinomas. In contrast, the number of NK cells significantly decreased in noninvasive carcinomas but increased in Grade 3 tumours. Conclusion Based on the above findings, Langerhans cells are considered to act as antigen-presenting cells in carcinomas, but it was not shown that they were activated by epithelial expression of HLA-DR in carcinomas.