Immunohistochemical characterization of plasma cells in Zoon's balanoposthitis and (pre)malignant skin lesions.

A retrospective study in 9 patients with Zoon's balanoposthitis was done to determine the immunoglobulin class distribution in the plasma cellular infiltrate. This was carried out on paraffin-embedded specimens using an unlabelled antibody peroxidase-antiperoxidase method. In all lesions IgG-producing plasma cells predominated. IgA- and IgD-positive cells were also present in about equal quantities but fewer than IgG. IgM-positive cells were either absent or present in very low numbers. Especially in erosive lesions a high number of plasma cells was noticed. The kappa/lambda ratio was variable with a preference for lambda in 5 of 8 cases. These findings are suggestive of a nonspecific polyclonal stimulation of B cells, which might be caused by a persistent infection. The above-mentioned findings were compared with premalignant and malignant skin lesions in which a major amount of plasma cells was present in the inflammatory infiltrate. Comparable results were obtained with slight variations. The role of plasma cells in these infiltrates is discussed.