HLA-DR ANTIGEN EXPRESSION AND LYMPHOCYTE SUBSETS IN TRANSITIONAL-CELLCARCINOMA OF THE URINARY-BLADDER - AN IMMUNOHISTOLOGICAL STUDY ON FROZEN-SECTIONS

Lymphocyte subpopulations (B cells, CD4, CD8), interleukin-20 receptor s (IL-2), monocytes/macrophages (Leu M(5)), and HLA-DR antigen express ion were studied immunohistochemically on frozen sections from 38 blad der cancer specimens. T cells predominated over B cells in all tumours . CD4-positive lymphocytes predominated over CD8 in the stroma (CD4/CD 8: 1.35/1), while in epithelial tumour cells CD8 was the prominent sub population (CD8/CD4: 1.75/1). Aberrant HLA-DR expression was found in 21.05 per cent of bladder tumours. A strong correlation between CD4 an d CD8 population densities and macrophages with the other subpopulatio ns was noticed. In HLA-DR-positive tumours, there was no correlation o f the percentage of positive cells with CD4- and CD8-positive lymphocy te populations. Various parameters including IL-2 receptors, B cells, CD8- and CD4-positive cells, and macrophages did not differ significan tly between the groups of tumours expressing and not expressing HLA-DR antigen. There were no statistically significant differences in the p opulation densities of B cells, CD8- or CD4-positive cells, IL-2 recep tor, monocytes/macrophages, and HLA-DR antigen expression among variou s clinicopathological parameters, including growth pattern, histologic al grade and clinical stage or patient's age and sex. These findings s uggest that in transitional cell carcinoma of the urinary bladder, HLA -DR antigen expression is independent of lymphocyte subpopulations. It is therefore possible that HLA-DR expression by tumour cells reflect the existence of separate HLA-DR-positive or HLA-DR-negative tumour cl ones.