Association of PXR and CAR Polymorphisms and Antituberculosis Drug-Induced Hepatotoxicity

A combination therapy of multiple drugs including isoniazid, rifampicin, ethambutol and pyrazinamide has been proven to be an effective option for the vast majority of tuberculosis (TB) patients. However, various adverse drug reactions (ADRs) limit its merit, with anti-TB drug-induced hepatotoxicity (ATDH) being a common and sometimes severe ADR. This study aimed to investigate the association between polymorphisms in two nuclear receptor genes, pregnane X receptor ( PXR ) and constitutive androstane receptor (CAR ), and the risk of ATDH in a Chinese population. Subjects with or without hepatotoxicity during anti-TB treatment were recruited. DNA was extracted from peripheral blood and genotypes of the selected single nucleotide polymorphisms (SNPs) were determined by using the improved multiplex ligation detection reaction technique. Three genetic models (additive, dominant, and recessive) as well as haplotype, SNP-SNP interaction analyses were used to evaluate the genetic risk of ATDH. A total of 502 subjects (203 ATDH and 299 non-ATDH) were enrolled. The results showed that the minor allele of rs7643645 and the H0010001 haplotype in PXR were associated with decreased risk of ATDH, suggesting that drug-metabolizing enzymes regulated by PXR are involved in the pathogenesis of ATDH. More studies are required to verify this result.