HLA class II antigen expression in conjunctival precancerous lesions and squamous cell carcinomas

PURPOSE: The expression of human leukocyte antigen (HLA) class II molecules on the cell surface is necessary for the presentation of peptide antigens to helper CD4 T lymphocytes of the immune system. We studied the immunoexpression of HLA class II antigen in conjunctival precursor lesions and conjunctival squamous cell carcinomas. METHODS: HLA class II antigen expression was analyzed in 8 conjunctival dysplasias, 6 carcinomas in situ and in 7 conjunctival squamous cell carcinomas, by immunoperoxidase staining with monoclonal antibody to HLA class II antigen on the archival clinical samples. Immunoanalysis was done by a semi quantitative method based on the intensity of staining and the percentage of stained cells. RESULTS: HLA class II antigen immunoexpression was heterogeneous in 8 conjunctival dysplasias and in 6 carcinoma in situ and negative in 7 conjunctival squamous cell carcinomas. CONCLUSIONS: Human leukocyte class II antigen immunoexpression is decreased in conjunctival precancerous and squamous cell carcinomas.