Clinical and immunogenetic correlates of abacavir hypersensitivity.
ABSTRACT A patch test (PT) may be useful in defining true abacavir hypersensitivity syndrome (AHS). Seven previously PT-positive patients remote from the original AHS were shown to have robust 24 h responses, supporting PT durability. HLA-B*5701 was present in all seven PT-positive versus one of 11 controls tolerating abacavir (P < 0.001). Five of seven PT (71%) versus one of 11 controls (9%) (P = 0.005) showed significant abacavir-specific CD8 proliferation, suggesting a direct role for HLA-B*5701-restricted CD8 cells in the pathophysiology of AHS.
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ABSTRACT: The basis for strong immunogenetic associations between particular human leukocyte antigen (HLA) class I allotypes and inflammatory conditions like Behçet's disease (HLA-B51) and ankylosing spondylitis (HLA-B27) remain mysterious. Recently, however, even stronger HLA associations are reported in drug hypersensitivities to the reverse-transcriptase inhibitor abacavir (HLA-B57), the gout prophylactic allopurinol (HLA-B58), and the antiepileptic carbamazepine (HLA-B*1502), providing a defined disease trigger and suggesting a general mechanism for these associations. We show that systemic reactions to abacavir were driven by drug-specific activation of cytokine-producing, cytotoxic CD8+ T cells. Recognition of abacavir required the transporter associated with antigen presentation and tapasin, was fixation sensitive, and was uniquely restricted by HLA-B*5701 and not closely related HLA allotypes with polymorphisms in the antigen-binding cleft. Hence, the strong association of HLA-B*5701 with abacavir hypersensitivity reflects specificity through creation of a unique ligand as well as HLA-restricted antigen presentation, suggesting a basis for the strong HLA class I-association with certain inflammatory disorders.Immunity 07/2008; 28(6):822-32. DOI:10.1016/j.immuni.2008.04.020 · 19.75 Impact Factor
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ABSTRACT: Introduction: Adverse drug reactions with an immune pathogenesis are a problem in the clinic and an impediment to drug development. T lymphocytes are believed to play a role in the pathogenesis; however, the nature of the drug interaction with immune receptors remains an area of debate. Areas covered: This article reviews recent advances in our understanding of drug hypersensitivity focusing specifically on the way in which drugs are displayed in MHC molecules. Most drugs associated with a high incidence of reactions have been shown to form protein-reactive metabolites. Hence, the relationship between drug metabolism and T-cell activation is discussed in detail. Expert opinion: The role of metabolism in pathogenesis of immunological drug reactions has only been studied with a small number of drugs where synthetic metabolites are available for functional studies. In each case, metabolite-responsive T cells have been detected. However, the field is skewed by the fact that most research is conducted using the parent compound in metabolically inert cell systems. We propose that research efforts are directed towards the synthesis of drug metabolites and/or drug-protein conjugates. Furthermore, analytical methods need to be developed to relate metabolite exposure to the T-cell response. For now, our understanding of the chemical basis of drug hypersensitivity is incomplete.Expert Opinion on Drug Metabolism & Toxicology 12/2014; 11(3):1-12. DOI:10.1517/17425255.2015.992780 · 2.93 Impact Factor
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ABSTRACT: Fifty-five percent of individuals with HLA-B*57:01 exposed to the antiretroviral drug abacavir develop a hypersensitivity reaction (HSR) that has been attributed to naïve T-cell responses to neo-antigen generated by the drug. Immunologically confirmed abacavir HSR can manifest clinically in less than 48 hours following first exposure suggesting that, at least in some cases, abacavir HSR is due to re-stimulation of a pre-existing memory T-cell population rather than priming of a high frequency naïve T-cell population. To determine whether a pre-existing abacavir reactive memory T-cell population contributes to early abacavir HSR symptoms, we studied the abacavir specific naïve or memory T-cell response using HLA-B*57:01 positive HSR patients or healthy controls using ELISpot assay, intra-cellular cytokine staining and tetramer labelling. Abacavir reactive CD8+ T-cell responses were detected in vitro in one hundred percent of abacavir unexposed HLA-B*57:01 positive healthy donors. Abacavir-specific CD8+ T cells from such donors can be expanded from sorted memory, and sorted naïve, CD8+ T cells without need for autologous CD4+ T cells. We propose that these pre-existing abacavir-reactive memory CD8+ T-cell responses must have been primed by earlier exposure to another foreign antigen and that these T cells cross-react with an abacavir-HLA-B*57:01-endogenous peptide ligand complex, in keeping with the model of heterologous immunity proposed in transplant rejection.PLoS ONE 02/2015; 10(2). DOI:10.1371/journal.pone.0117160 · 3.53 Impact Factor