Immunohistological aspects of cutaneous T‐cell infiltrates

SUMMARY In many benign and malignant skin disorders, lymphocytes and associated monocytic cells predominate among the various types of cells infiltrating the dermis and/or the epidermis. Immunohistological techniques utilized for the purpose of combining immunological parameters and morphological criteria have been reviewed. The rosetting techniques, enzyme histochemistry and immunohistological techniques using polyclonal and monoclonal antibodies were reported for light microscopy. In the field of immunoelectron microscopy, immunoperoxidase labelling and the immunogold technique were also subject to discussion. These techniques may be supplemented by various methods of cell biology (obtaining enriched cell suspensions of infiltrate cell subsets). The possiblity of quantitative studies was considered. Results obtained in cutaneous pathology using these techniques were reviewed and discussed. Among others, human skin tuberculin lesions and DNCB skin tests represent models of delayed hypersensitivity. Infiltrates in the following conditions were presented: non‐tumoral lesions (lichen planus, erythema multiform, erythema fixum, GVH and allograft rejection, cutaneous sarcoidosis and other infiammatory infiltrates); in lymphomas and related conditions; in tumoral lesions (warts and papillomas, peritumoral infiltrates around epidermal neoplasias). Finally Langerhans cells in infiammatory dermatosis, in skin tumours and in histiocytosis X were considered.