Pathogenesis of drug-induced exanthema

Background: In vitro data derived from drug-specific T cell clones have rev ealed that heterogeneous T cell subsets with distinct phenotypes (CD4+ > CD 8+ and cell functions (strong IL-5 production, cytotoxic potential) are gen erated. The aim of th is study was to elaborate the relevance of these find ings in vivo. Methods: Skin biopsy specimens from drug-induced maculopapula r exanthema and normal skin were analyzed for CD4, CD8, CD25, HLA-DR, CD54, perforin, granzyme B, IL-5 and IFN-gamma using immunohistochemistry. Resul ts: The majority of infiltrating lymphocytes in maculopapular drug eruption s were CD4+. Both CD4+ and CD8+ T cells expressed perforin and granzyme B a nd were partly located at the dermoepidermal junction and in the epidermis. in addition, strong immunoreactivity for IL-5 and moderate immunoreactivit y for IFN-gamma were observed in the mononuclear cell infiltrate. Conclusio ns: Our data indicate that skin infiltrating T cells with a cytotoxic poten tial and the ability to produce IL-5 and IFN-gamma may contribute to the da mage of keratinocytes and the activation of eosinophils which are typical f eatures of drug-induced maculopapular exanthema. Copyright (C) 2001 S. Karg er AG. Basel.