Abstract
We investigated the expression of HLA-DR antigen on 42 squamous cell carcinomas of head and neck using immunohistological methods. Our results indicate significant relationships between HLA-DR antigen expression on carcinomas and lymphocytic infiltration, that is, CD8 positive lymphocytes (CD8/CD3) infiltrated HLA-DR antigen positive carcinomas while CD4 positive cells (CD4/CD3) were found in HLA-DR negative carcinoma. The Ki-67 (a nuclear marker of proliferation) positive rate was lower on HLA-DR positive carcinomas than on negative carcinomas. However, there was no correlation with pathological differentiation, clinical stage or primary lesion. In vitro studies using several cytokines showed that IFN-γ induced expression of HLA-DR antigen and lowered the Ki-67 positive rate on squamous cell carcinomas. It seems that HLA-DR antigen expression on squamous cell carcinomas could be induced by cytokines released from the infiltrating lymphocytes.
