Distribution of CD1a-positive Langerhans cells and lymphocyte subsets in transitional cell carcinoma of the urinary bladder. An immunohistological study on frozen sections.

The distribution of CD1a-positive Langerhans cells, CD4-positive T-helper cells, and CD8-positive T-suppressor cells in 36 patients with transitional cell carcinoma of the urinary bladder was studied immunohistochemically on frozen sections. Multiple tissue specimens from the tumour, the adjacent mucosa, and random bladder wall biopsies were examined. Langerhans cells were mainly interspersed among the tumour cells, whereas T-helper cells were present in aggregates in the stroma. T-suppressor cells were present both in aggregates in the stroma and among the tumour cells. There was a marginal relationship between the density of Langerhans cells and the density of T-helper/inducer cells and a good relationship with CD8-positive cells. There was no statistically significant difference in the population density of Langerhans cells associated with the various clinicopathological variables, including growth pattern, histological grade and stage, or patient's age and sex. On the contrary, a statistically significant difference was found in the CD1a/CD4 ratio among specimens of different grades. These results show that CD1a cell populations correlate with T-cell populations in bladder cancer, suggesting that Langerhans cells take part in the immune response carried out by T lymphocytes, their task being apparently antigen presentation.