CD4-ALPHA-BETA-POSITIVE AND TCR-ALPHA-BETA-POSITIVE T-LYMPHOCYTES PREDOMINANTLY INFILTRATED INTO WELL-MODERATELY DIFFERENTIATED COLON ADENOCARCINOMA TISSUES

Intraepithelial T lymphocytes have been reported as being functional i n the growth of epithelial cells and also in the discrimination of abe rrant cells, whereas their function against colon adenocarcinoma cells is obscure. The phenotype of colon intraepithelial T lymphocytes has been found in patients with inflammatory bowel diseases but not in pat ients with colon adenocarcinoma. In this study, we investigated cell s urface markers of tumor-infiltrating T lymphocytes of adenocarcinoma o f the colon and rectum at various grades of differentiation and intrae pithelial T lymphocytes of adjacent normal colon by enzyme immunostain ing. Among intraepithelial T lymphocytes of the normal colon, CD8- and TCR gamma delta-positive T lymphocytes were predominant as described. In contrast, tumor-infiltrating T lymphocytes of well-moderately diff erentiated adenocarcinoma of the colon and rectum were predominantly C D4- and TCR alpha beta-positive. The decrease of TCR gamma delta-posit ive T lymphocytes and the increase of CD4 and TCR alpha beta-positive T lymphocytes in adenocarcinoma tissues of the colon and rectum sugges ts that an alteration of the local immune system participates in the f ormation of adenoma and/or adenocarcinoma of the colon and rectum, res ulting in infiltration of CD4-positive T lymphocytes that have certain activity against transformed cells.