Background Carbamazepine causes various forms of hypersensitivity reactions, ranging from maculopapular exanthema to severe blistering reactions. The HLA-B*1502 allele has been shown to be strongly correlated with carbamazepine-induced Stevens–Johnson syndrome and toxic epidermal necrolysis (SJS–TEN) in the Han Chinese and other Asian populations but not in European populations. Methods We performed a genomewide association study of samples obtained from 22 subjects with carbamazepine-induced hypersensitivity syndrome, 43 subjects with carbamazepine-induced maculopapular exanthema, and 3987 control subjects, all of European descent. We tested for an association between disease and HLA alleles through proxy single-nucleotide polymorphisms and imputation, confirming associations by high-resolution sequence-based HLA typing. We replicated the associations in samples from 145 subjects with carbamazepine-induced hypersensitivity reactions. Results The HLA-A*3101 allele, which has a prevalence of 2 to 5% in Nor...

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HLA-A*3101 and carbamazepine-induced hypersensitivity reactions in Europeans

When drug reactions resembling allergy occur, they are called drug hypersensitivity reactions (DHRs) before showing the evidence of either drug-specific antibodies or T cells. DHRs may be allergic or nonallergic in nature, with drug allergies being immunologically mediated DHRs. These reactions are typically unpredictable. They can be life-threatening, may require or prolong hospitalization, and may necessitate changes in subsequent therapy. Both underdiagnosis (due to under-reporting) and overdiagnosis (due to an overuse of the term ‘allergy’) are common. A definitive diagnosis of such reactions is required in order to institute adequate treatment options and proper preventive measures. Misclassification based solely on the DHR history without further testing may affect treatment options, result in adverse consequences, and lead to the use of more-expensive or less-effective drugs, in contrast to patients who had undergone a complete drug allergy workup. Several guidelines and/or consensus documents on general or specific drug class-induced DHRs are available to support the medical decision process. The use of standardized systematic approaches for the diagnosis and management of DHRs carries the potential to improve outcomes and should thus be disseminated and implemented. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), formed by the European Academy of Allergy and Clinical Immunology (EAACI), the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), and the World Allergy Organization (WAO), has decided to issue an International CONsensus (ICON) on drug allergy. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences and deficiencies of evidence, thus providing a comprehensive reference document for the diagnosis and management of DHRs.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/all.12350

International Consensus on drug allergy.

Background Carbamazepine, an anticonvulsant and a mood-stabilizing drug, is the main cause of the Stevens–Johnson syndrome (SJS) and its related disease, toxic epidermal necrolysis (TEN), in Southeast Asian countries. Carbamazepine-induced SJS–TEN is strongly associated with the HLA-B*1502 allele. We sought to prevent carbamazepine-induced SJS–TEN by using HLA-B*1502 screening to prospectively identify subjects at genetic risk for the condition. Methods From 23 hospitals in Taiwan, we recruited 4877 candidate subjects who had not taken carbamazepine. We genotyped DNA purified from the subjects' peripheral blood to determine whether they carried the HLA-B*1502 allele. Those testing positive for HLA-B*1502 (7.7% of the total) were advised not to take carbamazepine and were given an alternative medication or advised to continue taking their prestudy medication; those testing negative (92.3%) were advised to take carbamazepine. We interviewed the subjects by telephone once a week for 2 months to monitor them ...

https://www.nejm.org/doi/pdf/10.1056/NEJMoa1009717

Carbamazepine-Induced Toxic Effects and HLA-B*1502 Screening in Taiwan

BackgroundStevens–Johnson syndrome (SJS) and its severe form, toxic epidermal necrolysis (TEN), are rare but life-threatening cutaneous adverse reactions to drugs, especially to allopurinol, carbamazepine, lamotrigine, phenobarbital, phenytoine, sulfamethoxazole, oxicam and nevirapine. Recently, a s

A European study of HLA-B in Stevens-Johnson syndrome and toxic epidermal necrolysis related to five high-risk drugs.

Epidermal necrolysis (EN)--either Stevens-Johnson syndrome (SJS) or toxic EN (TEN)--is a severe drug reaction. We constructed and evaluated a specific algorithm, algorithm of drug causality for EN (ALDEN), in order to improve the individual assessment of drug causality in EN. ALDEN causality scores were compared with those from the French pharmacovigilance method in 100 cases and the case-control results of the EuroSCAR study. Scores attributed by ALDEN segregated widely. ALDEN pointed to a "probable" or "very probable" causality in 69/100 cases as compared to 23/100 with the French method (P < 0.001). It scored "very unlikely" causality for 64% of medications vs. none with the French method. Results of ALDEN scores were strongly correlated with those of the EuroSCAR case-control analysis for drugs associated with EN (r = 0.90, P < 0.0001), with probable causality being reported in 218/329 exposures. ALDEN excluded causality in 321 drugs that the case-control analysis had described as "probably not associated" and in 22/233 drugs that had been described as inconclusive exposures. Being more sensitive than a general method, ALDEN, which correlates well with case-control analysis results, can be considered a reference tool in SJS/TEN.

ALDEN, an algorithm for assessment of drug causality in Stevens-Johnson Syndrome and toxic epidermal necrolysis: comparison with case-control analysis.

The anticonvulsant carbamazepine (CBZ) frequently causes cutaneous adverse drug reactions (cADRs), including maculopapular eruption (MPE), hypersensitivity syndrome (HSS), Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). We reported that SJS/TEN caused by CBZ is strongly associat

Shu Ling Hu

Papers

Genetic susceptibility to carbamazepine-induced cutaneous adverse drug reactions.