Abstract
Background Anti-tumor necrosis factor-alpha (TNF-alpha) is used for the treatment of severe cases of IBD, including Crohn's disease (CD) and ulcerative colitis (UC). However, one-third of the patients do not respond to the treatment. We have previously investigated whether single nucleotide polymorphisms (SNPs) in genes involved in inflammation were associated with response to anti-TNF therapy among patients with CD or UC. Aim A new cohort of patients was established for replication of the previous findings and to identify new SNPs associated with anti-TNF response. Methods Fifty-three SNPs assessed previously in cohort 1 (482 CD and 256 UC patients) were genotyped in cohort 2 (587 CD and 458 UC patients). The results were analysed using logistic regression (adjusted for age and gender). Results Ten SNPs were associated with anti-TNF response either among patients with CD (TNFRSF1A(rs4149570) (OR: 1.92, 95% CI: 1.02-3.60, P = 0.04), IL18(rs187238) (OR: 1.35, 95% CI: 1.00-1.82, P = 0.05), and JAK2(rs12343867) (OR: 1.35, 95% CI: 1.02-1.78, P = 0.03)), UC (TLR2(rs11938228) (OR: 0.55, 95% CI: 0.33-0.92, P = 0.02), TLR4(rs5030728) (OR: 2.23, 95% CI: 1.24-4.01, P = 0.01) and (rs1554973) (OR: 0.49, 95% CI: 0.27-0.90, P = 0.02), NFKBIA(rs696) (OR: 1.45, 95% CI: 1.06-2.00, P = 0.02), and NLRP3(rs4612666) (OR: 0.63, 95% CI: 0.44-0.91, P = 0.01)) or in the combined cohort of patient with CD and UC (IBD) (TLR4(rs5030728) (OR: 1.46, 95% CI: 1.01-2.11, P = 0.04) and (rs1554973)(OR: 0.80, 95% CI: 0.65-0.98, P = 0.03), NFKBIA(rs696) (OR: 1.25, 95% CI: 1.01-1.54, P = 0.04), NLRP3(rs4612666) (OR: 0.73, 95% CI: 0.57-0.95, P = 0.02), IL1RN(rs4251961) (OR: 0.81, 95% CI: 0.66-1.00, P = 0.05), IL18(rs1946518) (OR: 1.24, 95% CI: 1.01-1.53, P = 0.04), and JAK2(rs12343867) (OR: 1.24, 95% CI: 1.01-1.53, P = 0.04)). Conclusions The results support that polymorphisms in genes involved in the regulation of the NF kappa B pathway (TLR2, TLR4, and NFKBIA), the TNF-alpha signalling pathway (TNFRSF1A), and other cytokine pathways (NLRP3, IL1RN, IL18, and JAK2) were associated with response to anti-TNF therapy. Our multi-SNP model predicted response rate of more than 82% (in 9% of the CD patients) and 75% (in 15% of the UC patients), compared to 71% and 64% in all CD and UC patients, respectively. More studies are warranted to predict response for use in the clinic.