title: Detection and quantification of drug-specific T cells in penicillin allergy.
abstract: Drug allergic reactions presenting as maculo-papular exanthema (MPE) are mediated by drug-specific T cells. In this study, the frequency of circulating specific T cells was analyzed by interferon-gamma (IFN-gamma) enzyme-linked immunospot assay in 22 patients with an allergic MPE to amoxicillin (amox). Amox-specific circulating T cells were detected in 20/22 patients with frequencies ranging from 1 : 8000 to 1 : 30 000 circulating leucocytes. No reactivity was observed in 46 control patients, including 15 patients with immunoglobulin E-mediated allergy to amoxicillin, 11 patients with a history of drug-induced MPE but tolerant to amoxicillin and 20 healthy individuals. Furthermore, amox-specific T cells were still detectable several years after the occurrence of the allergic reaction even after strict drug avoidance. Finally, analysis of drug-specific T cells in one patient allergic to ticarcillin (a penicillin antibiotic distinct from amox) revealed the presence of IFN-gamma-producing T cells reactive to ticarcillin and several other betalactam antibiotics, suggesting that the IFN-gamma ELISPOT assay is able to detect T cell cross-reactivity against chemically related drugs. These findings confirm that drug-induced MPE is associated with the presence of specific T cells in blood and further suggest that the IFN-gamma ELISPOT is a sensitive assay which could improve the diagnosis of betalactam allergy.
authors.affiliation: Université Lyon, Oullins, France.
authors.forename: A
authors.initials: A
authors.lastname: Rozieres
authors.forename: A
authors.initials: A
authors.lastname: Hennino
authors.forename: K
authors.initials: K
authors.lastname: Rodet
authors.forename: M-C
authors.initials: MC
authors.lastname: Gutowski
authors.forename: N
authors.initials: N
authors.lastname: Gunera-Saad
authors.forename: F
authors.initials: F
authors.lastname: Berard
authors.forename: G
authors.initials: G
authors.lastname: Cozon
authors.forename: J
authors.initials: J
authors.lastname: Bienvenu
authors.forename: J-F
authors.initials: JF
authors.lastname: Nicolas
mesh_terms: D000293:Adolescent; D000328:Adult; D000658:Amoxicillin / Q000009:adverse effects / Q000276:immunology*; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D004342:Drug Hypersensitivity / Q000209:etiology / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005076:Exanthema / Q000139:chemically induced / Q000276:immunology; D006801:Humans; D007223:Infant; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D010406:Penicillins / Q000009:adverse effects / Q000276:immunology*; D012871:Skin Diseases / Q000139:chemically induced / Q000276:immunology; D012882:Skin Tests; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D000658:Amoxicillin; D007371:Interferon-gamma