Immunohistological analysis of lymphocyte subpopulations infiltrating breast carcinomas and benign lesions

We characterized different subpopulations of infiltrating mononuclear cells using 8 monoclonal antibodies (MAbs) on serial cryosections of breast tissue from 85 cancer patients and 32 samples of benign lesions, and the ABC technique. In general, lymphocytes were found more frequently and more abundantly in cancerous lesions. The infiltrates consisted mainly of T‐cells in close contact with malignant cell‐nests. T‐helper/inducer cells clearly predominated over T‐suppressor/ cytotoxic cells in neoplastic tissues, whereas in benign tissues the T‐helper/suppressor ratios seemed to be well balanced. While a few MAb Leu‐7 (HNK‐l)‐reactive NK cells were found in the stroma of the breast tumors, none could be identified in the noncancerous lesions. The correlation of these data with histology and tumor stage of patients has been evaluated by a quantitative approach using planimetry in an interactive registration system.