The role of macrophages in the differentiation process of ureteral polyps.

Objective To evaluate the role of macrophage infiltration in the differentiation process of ureteral polyps and cancers. Methods This retrospective immunohistochemical study analysed archival samples of pathologically-confirmed specimens of low- and high-grade ureteral cancer, ureteral papilloma and ureteral polyps. The samples were immunohistochemically stained for cluster of differentiation (CD)4, CD8, CD16, CD25, CD56 and CD68 using immunofluorescence in order to identify different T-lymphocyte populations and macrophages. Results A total of 70 specimens were included in the analysis: 21 specimens of ureteral cancer, 17 specimens of ureteral papilloma, and 32 specimens of ureteral polyps. The largest proportion of CD4+CD25+ regulatory T cells was observed in the low-grade ureteral cancer group and almost none were observed in ureteral papillomas. The largest proportion of CD8+ cytotoxic T-lymphocytes was observed in the ureteral polyps. The largest proportion of CD56+ natural killer cells was detected in the ureteral polyps, with very low levels observed in the other three groups. The largest proportion of CD16+CD68+ macrophages was observed in the high-grade ureteral cancer group, which was significantly higher than that observed in the ureteral papillomas. Conclusions This study revealed that CD16+CD68+ macrophages appear to participate in ureteral neoplastic transformation.