Expression of class I and class II major histocompatibility complex antigens on oral mucosal epithelium.

The expression of the Class I and Class II major histocompatibility antigens on oral mucosa was investigated using type-specific monoclonal antibodies. Class I antigen expression varied between various sites and in uncomplicated inflammatory responses appeared to be suppressed. HLA-DR antigen expression was only present on epithelial cells in the presence of extraneous immunocompetent cells. Oral mucosa did not express HLA-DQ antigens. The expression of Class I and Class II antigens varied between disease states exhibiting proliferative or destructive tissue responses. The pattern of Class I and Class II antigen expression is consistent with either MHC-restricted cellular interactions and subsequent destruction of epithelial cells or a protective role in non-destructive conditions.