UC San Diego

BACKGROUND: Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare, severe adverse event during treatment with raltegravir. The occurrence of DRESS syndrome during treatment with other drugs is strongly associated with particular HLA alleles. METHODS: We performed HLA testing in 3 of the 5 patients previously reported to have developed raltegravir-induced DRESS syndrome and in 1 previously unreported patient. We then used virtual modeling to visualize interactions between raltegravir and the imputed HLA molecule. RESULTS: Five of the 6 patients who developed raltegravir-induced DRESS syndrome were African, and 1 was Hispanic. HLA typing was performed in 4 patients, all of whom carried both the HLA-B*53 allele and the HLA-C*04 allele to which it is commonly haplotypic. No other HLA alleles were shared by all of the tested patients. Given the approximate prevalence of HLA-B*53 carriage in African (20%) and Hispanic (6%) populations, the probability of all 4 patients being HLA-B*53 carriers, and 2 of 3 African patients being homozygous for HLA-B*53:01, is approximately 0.00002. CONCLUSIONS: These data implicate the prevalent African allele HLA-B*53:01 in the immunopathogenesis of raltegravir-induced DRESS syndrome. Although the immunopathogenic mechanisms are currently unknown, virtual modeling suggests that raltegravir may bind within the antigen binding cleft of the HLA-B*53:01 molecule, but not within the closely related HLA-B*35:01 molecule. Further studies are necessary to confirm the strength of the association between carriage of the HLA-B*53:01 allele and raltegravir-induced DRESS syndrome, and the potential utility of HLA screening before raltegravir treatment.