Bacillus Calmette-Guérin-treated superficial bladder cancer: correlation of morphology with immunophenotyping

Thirty-five biopsies from 19 patients with superficial transitional cell carcinoma of the bladder, treated with intravesical bacillus Calmette-Guérin (BCG), were assessed histologically and immunohistochemically. Pretreatment biopsies were available for comparison in all cases and five cases of non-specific cystitis were also examined. The inflammatory infiltrate was assessed with a streptavidin-biotin-peroxidase method using UCHL1, MT1, LN3, L26, HAM56, MAC387, Leu7 and anti-S100 in paraffin sections, and in 18 specimens were frozen tissues were available, Leu1, 2, 3, 4, 14, OKT10, HLA-DR and anti-Tac antibodies were applied. Post-treatment bladder biopsies showed severe oedema and a variable degree of inflammation. A granulomatous inflammation was seen in 11 cases, with granulomas present in six prostatic biopsies and acid-fast bacilli in two cases. The lymphoid infiltrate in all biopsies were largely T lymphocytes with a predominance of T helper cells present, often as a band-like infiltrate pressing against the residual epithelium, or the denuded bladder surface, and distributed in the vicinity of the granulomas. Activated lymphocytes were prominent in seven cases, although a moderate infiltrate of such cells was seen in all instances. Tac antigen was only occasionally expressed, and in a few NK cells were present among the infiltrates. In eight cases, HLA-DR was expressed in epithelial cells following BCG treatment, whereas all pre-treatment epithelial were negative.