IMMUNOPATHOLOGY OF TOXIC EPIDERMAL NECROLYSIS - KERATINOCYTES, HLA-DR EXPRESSION, LANGERHANS CELLS, AND MONONUCLEAR-CELLS - AN IMMUNOPATHOLOGIC STUDY OF 5 CASES

Background. - Toxic epidermal necrolysis is a potentially severe mucocutaneous affliction whose cause is usually drug related. To further charcterize the nature of the dermal mononuclear infiltrate as well as the epidermal alterations observed by standard microscopy, we studied five cases of toxic epidermal necrolysis using labeled monoclonal antibodies. Results. - On clinically involved areas of skin, the following occurs: (1) the dermal infiltrate is composed mainly of activated T lymphocytes, with a predominant helper phenotype; (2) the number of Langerhans cells is decreased; and (3) keratinocytes express HLA-DR molecules, normally absent on their surface. Conclusions. - These findings, although not specific, are consistent with an immune cellular reaction, but they could also be linked to an inflammatory reaction initiated by epidermal damages whatever its primary mechanism.