Immunopathologic demonstration of MAC387+ UCHL1+ cells in bullous skin diseases.

Immunopathologic aspects of bullous skin diseases were studied in paraffin sections of thirty-three skin biopsy specimens utilizing monoclonal antibodies directed against histiocytes, helper/inducer T lymphocytes, and Langerhans cells in skin lesions. Laboratory examinations revealed that either more or fewer of the standard number of helper/inducer T lymphocytes (UCHL1+) were observed in the upper dermis in 84.8% of the cases examined, particularly in the various forms of pemphigus; histiocytes (MAC387+) were also found to occur in the upper dermis in 45.5% of the cases and blisters in 27.3% of the cases, particularly in pemphigus erythematosus and dermatitis herpetifomis. In 54.5% of all the cases, both UCHL1+ and MAC387+ cell infiltrates predominated in the upper dermis. These findings suggest that a cell-mediated immune response may also be important in the pathogenesis of bullous skin diseases. It may be possible that antigen from keratinocytes can produce ETAF, and that IL1 activating T lymphocytes and histiocytes also produce IL1 activating T cells, particularly helper/inducer T cells. Such activities would further promote the increase of B cell function and immunoglobulin synthesis.