HLA-B57:01+ abacavir-naive individuals have specific T cells but no patch test reactivity

• Published in: Journal of allergy and clinical immunology Vol. 132; no. 3; pp. 756 - 758
• Main Authors: Schnyder, Benno, MD, Adam, Jacqueline, PhD, Rauch, Andri, MD, Thurnheer, Maria C., MD, Pichler, Werner J., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2013; Elsevier Limited
• Subjects: Adolescent; Allergy and Immunology; Anti-HIV Agents - adverse effects; Dideoxynucleosides - adverse effects; Drug Hypersensitivity - diagnosis; Drug Hypersensitivity - immunology; Female; HIV; HIV Infections - drug therapy; HIV Infections - immunology; HLA-B Antigens - immunology; Human immunodeficiency virus; Humans; Infections; Lymphocytes; Male; Patch Tests; Patients; Peptides; T-Lymphocytes - immunology
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2013.04.013

[...]HLA-B*57:01 has become an established marker for the identification of patients at risk of AH.1 (b) This strong association is not due to a hapten-like reaction to an abacavir-altered peptide but due to noncovalent binding of unmetabolized abacavir to the peptide-binding groove of HLA-B*57:01,2-5 as proposed in the p-i concept.6 Moreover, this abacavir binding to the HLA-B*57:01 pocket may interfere with peptide loading and cause an alteration of the presented peptide repertoire.2-4 The presentation of novel peptides may then elicit either an autoimmune reaction or an alloimmune-like reaction.2-4 (c) Abacavir-specific CD8+ T cells are detectable in the circulating blood of B*57:01+ individuals, which were never exposed to abacavir,5,7 and (d) abacavir-specific patch tests in patients with AH show high test accuracy (79%) with an excellent specificity (100%).1 On the basis of these peculiarities and findings, we performed a study (approved by the Ethics Committee of the canton of Bern, Switzerland) in which we asked the following questions: [...]while all HLA-B*57:01+ individuals have abacavir-reactive T cells in the circulation, skin testing in abacavir-naive individuals is negative and does not appear to sensitize.