Glutathione-S-transferase genotypes and the adverse effects of azathioprine in young patients with inflammatory bowel disease

Gabriele Stocco, Stefano Martelossi, Arrigo Barabino, Giuliana Decorti, Flora Bartoli, Marcello Montico, Annalisa Gotti, Alessandro Ventura

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Adverse drug reactions to azathioprine, the prodrug of 6-mercaptopurine, occur in 15%-38% of patients and the majority are not explained by thiopurine-S-methyltransferase (TPMT) deficiency. Azathioprine is known to induce glutathione depletion and consumption of glutathione is greater in cells with high glutathione-S-transferase (GST) activity compared with those with low activity; moreover, some reports indicate that GST might play a direct role in the reaction of glutathione with azathioprine. The association between polymorphisms of GST-M1, GST-P1, GST-T1, and TPMT genes and the adverse effects of azathioprine was therefore investigated. Methods: Seventy patients with inflammatory bowel disease (IBD), treated with azathioprine, were enrolled and clinical data were retrospectively determined. TPMT and GST genotyping were performed by polymerase chain reaction (PCR) assays on DNA extracted from blood samples. Results: Fifteen patients developed adverse effects (21.4%); there was a significant underrepresentation of the GST-M1 null genotype among patients developing adverse drug reactions to azathioprine (odds ratio [OR] = 0.18, 95% confidence interval [CI] = 0.037-0.72, P = 0.0072) compared with patients who did not develop adverse effects. Patients heterozygous for TPMT mutations presented a marginally significant increased probability of developing adverse effects (OR = 6.38, 95% CI = 0.66-84.1, P = 0.062). Moreover, among the 55 patients who did not develop adverse effects, there was a significant underrepresentation of the GST-M1 null genotype among patients who displayed lymphopenia as compared with those that did not display this effect of azathioprine (OR = 0.15, 95% CI = 0.013-1.08, P = 0.032). Conclusion: Patients with IBD with a wildtype GST-M1 genotype present increased probability of developing adverse effects and increased incidence of lymphopenia during azathioprine treatment.

Original languageEnglish
Pages (from-to)57-64
Number of pages8
JournalInflammatory Bowel Diseases
Volume13
Issue number1
DOIs
Publication statusPublished - 2007

Keywords

  • Adverse effects
  • Azathioprine
  • Genotyping
  • Glutathione-S-transferase
  • Inflammatory bowel disease

ASJC Scopus subject areas

  • Gastroenterology

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