Analysis of mucosal bladder leucocyte subpopulations in patients treated with intravesical Bacillus Calmette-Guerin.

Immunohistochemical techniques were used to investigate leucocyte subpopulations in the bladders of patients with superficial transitional cell carcinoma treated with BCG Pasteur. Leucocyte subsets were enumerated with a panel of monoclonal antibodies which included CD3, CD4, CD8, TQ1, Leu7, CD15, HLA-DR, CD25, CD22. We demonstrated in the bladders of patients treated with BCG a particular lymphocyte population; the major subset was an inducer (CD4+, TQ1-) which was activated (CD25+, HLA-DR+) and associated with polymorphonuclear eosinophils. There was neither inducer of suppression nor major cytotoxic/suppressive subsets. CD8+ and NK cells could not be the primary mediators of BCG activity. These data supported the hypothesis of a helper T lymphocyte activity associated with lymphokine production and activation of effector killer cells.