Expression and modulation of class I and class II histocompatibility leukocyte antigens on human soft tissue sarcomas.

Background: Class I and Class II histocompatibility leukocyte antigens (HLA) play an important role in the antigenic recognition and target cell killing by T-lymphocytes. Their expression and modulation with gamma interferon on human soft tissue sarcomas were investigated.
Methods: The phenotypic expressions of Class I and Class II HLA were determined by avidin-biotin immunoperoxidase staining using two monoclonal antibodies W6/32 and MEL3, respectively.
Results: The present study showed that soft tissue sarcomas frequently had demonstrable Class I HLA and less-frequently expressed Class II HLA: The staining for Class I HLA was more diffuse, and the staining for Class II HLA was generally patchy in appearance. The expressions of two antigens on cultured sarcoma cells were found in accordance with the findings of sarcoma tumors. The expression of Class I antigen was enhanced, and Class II was induced in two cell lines by gamma interferon. The in vitro modulation of HLA with gamma interferon was reversible. Gamma interferon at the testing dose did not have cytotoxic or antiproliferative effects on either cell lines.
Conclusions: Through the modulation of HLA on soft tissue sarcomas, gamma interferon may play a role in the clinical management of sarcomas.