Allopurinol-induced severe cutaneous adverse reactions in Vietnamese: the role of alleles and other risk factors.

To reveal the association of three class I alleles, including and , and allopurinol-induced severe cutaneous adverse reactions (SCARs) in Vietnamese patients. A case-control study on 100 allopurinol-induced SCARs patients, 183 tolerant controls and 810 population controls was performed. The and alleles were detected with the nested allele-specific PCR method; the allele was detected with the sequence-specific primer PCR method. There were strong associations between and and allopurinol-induced SCARs. Specific associations were found between and Stevens-Johnson syndrome/toxic epidermal necrolysis and between and drug reaction with eosinophilia and systemic symptoms, with a gene dosage effect. The multivariate regression analysis indicated two significant independent risk factors: and estimated glomerular filtration rate <60 ml/min/1.73 m. The specificity, positive predictive value and negative predictive value of testing were higher than the or the multiplex testing, especially in patients with impaired renal function. The results supported pre-treatment testing in Vietnamese patients with declined renal function to prevent SCARs.