HLA expression in pre-invasive cervical neoplasia in relation to human papilloma virus infection.

A significant proportion of cervical carcinomas show loss of major histocompatibility complex human leucocyte antigen (HLA) class I expression while upregulating HLA class II expression. These changes may have direct consequences for immune surveillance of the human papilloma virus (HPV) infection which is strongly associated with cervical malignancy. A relationship between changes in HLA expression and HPV infection may be evident in the evolution of premalignant disease. This immunohistological study of 104 colposcopic biopsies establishes that HLA class II expression occurs in a significant proportion of squamous epithelia showing histological evidence of wart virus infection and cervical intraepithelial neoplasia (CIN) I to III. In comparison, alteration of HLA class I expression in cervical premalignant lesions is rare. There is no correlation between the detection of high risk HPV DNA (types 16, 18, 31 and 33) by polymerase chain reaction (PCR) and the MHC class II phenotype of the lesion. This suggests that altered HLA class II expression is neither a consequence nor a prerequisite for HPV infection.