Langerhans cells in human warts.

Seventy-six warts (15 plantar, 38 hand, 16 miscellaneous and seven anogenital lesions) taken from 55 patients, were studied by indirect immunofluorescence with monoclonal antibodies specific for T-cell subsets, Langerhans cells (LC) and HLA-DR antigen. The results were related to the presence of viral antigen. Approximately 80% of the lesions showed an infiltrate. Only 19 lesions contained helper/inducer or suppressor/cytotoxic T cells. The distribution of LC was abnormal in 65% of biopsies which contained LC in the dermis, and 29% were devoid of LC in the epidermis. Many lesions had reduced numbers of LC in the epidermis. The disappearance of LC from the epidermis was related to the presence of viral antigen, but not to the presence of particular T-cell subsets. Infiltrating cells were sometimes HLA-DR-positive, whereas basal cells did not express HLA-DR antigen, irrespective of the density of the infiltrate.