LOCAL IMMUNE-RESPONSE IN HYPERPLASTIC LESIONS OF THE LARYNX

A retrospective morphologic and immunohistochemical study of 25 benign and 5 malignant laryngeal hyperplastic lesions was performed concerning a local immune response which might be characteristic and of prognostic value for each particular group of these alterations, using Kambic's classification, especially for precancerous and cancerous lesions. On paraffin and frozen sections, 7 monoclonal antibodies against various leukocytic antigens were used. CD43 and CD45RO T lymphocytes were the predominant cells in the infiltrates, and their frequency increased according to the degree of hyperplastic lesions. Next in frequency were CD4 cells, and a predominance of CD4 over CD8 cells was an obvious finding. The infiltration of CD68-, CD57-, and CD20-positive cells was generally weak. The intensity and composition of the local reaction in all cases of atypical hyperplasias was nearly identical, regardless of their subsequent behaviour. No apparent cytotoxic effects on the epithelial cells, either in precancerous or in cancerous lesions, were observed. Thus, the immunocompetent cells in the epithelial and stromal tissue are most likely not an effective defense in preventing hyperplastic lesions from becoming malignant. It seems that laryngeal hyperplastic lesions do not provoke an essential defense immune response, but the present local inflammatory reaction might be a constituent part of etiologically different inflammations which may lead to unfavorable lesions.