Local immune response in endometrial carcinomas

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Abstract
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.