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.