Immunopathology of toxic epidermal necrolysis. Keratinocytes, HLA-DR expression, Langerhans cells, and mononuclear cells: an immunopathologic study of five cases.

BACKGROUND

Toxic epidermal necrolysis is a potentially severe mucocutaneous affliction whose cause is usually drug related. To further characterize 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.