title: Lymphocyte activation in cutaneous drug reactions.
abstract: Peripheral blood lymphocytes from both drug-induced immediate and delayed cutaneous hypersensitivity reactions frequently can be stimulated in vitro with the particular culprit drug. Immunohistochemical analysis has identified CD8+ T cells as the predominant epidermal T-cell subset in drug-induced maculopapular and bullous eruptions and in patch-test reactions to beta-lactam antibiotics. Beta-lactam-specific peripheral and epidermal T lymphocytes from bullous exanthems were predominantly T-cell receptor alpha/beta+, CD8+, CD4-. Three CD8+ epidermal T-cell clones from penicillin-induced bullous exanthems displayed a TH1-like cytokine pattern and proliferated in an antigen- and major histocompatibility complex-specific manner. These epidermal T-cell clones were cytotoxic against autologous B cells upon stimulation through the T-cell receptor and against epidermal keratinocytes in lectin-induced cytotoxicity assays. In contrast, peripheral T-cell lines from patients with penicillin-induced urticarial exanthems were predominantly T-cell receptor alpha/beta+, CD4+, CD8- and displayed a Th2-like cytokine pattern. CD8+ dermal T cells from a sulfamethoxazole-induced bullous exanthem proliferated in vitro in response to sulfamethoxazole. This T-cell proliferation was significantly increased in the presence of microsomes, which suggests that microsomal enzymes, such as cytochrome P450 enzymes, generate highly reactive metabolites which are the nominal antigens for T-cell activation. In summary, drugs may be processed and presented in different ways, which is reflected by the observation that Th1-like CD8+ T cells are primarily activated in delayed cutaneous hypersensitivity reactions, whereas Th2-like T-cell responses are present in patients with drug-induced urticarial exanthems.
authors.affiliation: Department of Dermatology, Medical Faculty, RWTH Aachen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hertl
authors.forename: H F
authors.initials: HF
authors.lastname: Merk
mesh_terms: D000941:Antigens / Q000276:immunology; D002999:Clone Cells; D003875:Drug Eruptions / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008213:Lymphocyte Activation; D012867:Skin / Q000187:drug effects*; D013601:T-Lymphocytes / Q000473:pathology
chemical_list: D000941:Antigens