Correlations of genetic polymorphisms of tumor necrosis factor-related apoptosis-inducing ligand gene and its plasma phenotype with ulcerative colitis

Abstract

To explore the correlations of genetic polymorphisms in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and the plasma levels of soluble TRAIL (sTRAIL) with ulcerative colitis (UC). From May 2004 to April 2011, a total of 393 UC patients were recruited from Second and First Affiliated Hospitals of Wenzhou Medical College and Second Renmin Hospital of Wenzhou City. During the same period, a total of 1292 healthy controls were recruited from Physical Examination Center at Second Affiliated Hospital of Wenzhou Medical College. After PCR amplification, the genetic polymorphisms in TRAIL (G1525A, G1588A, C1595T) genes were examined by direct sequencing, and the haplotype analysis were also performed in all study subjects. Furthermore, the plasma levels of sTRAIL were determined by enzyme-linked immunosorbent assay (ELISA). The frequencies of variant genotypes in TRAIL (G1525A, G1588A, C1595T) genes were significantly lower in the UC patients than those in the controls (all P < 0.01). Both of variant allele frequencies in TRAIL G1525A and G1588A were significantly decreased in UC patients (40.08% (315/786) vs 54.95% (1420/2584), 49.49% (389/786) vs 55.53% (1435/2584), both P < 0.01). However, the variant allele frequency in TRAIL C1595T gene was not significantly lower in the UC patients (P = 0.133). According to disease severity, the UC patients were divided into mild, intermediate and severe groups. The frequencies of variant allele (T) and genotype (CT + TT) in TRAIL C1595T gene were also significantly higher in the patients with severe UC than those in others (63.50% (127/200) vs 49.15% (288/586), 77.00% (77/100) vs 61.43% (180/293), both P < 0.01). In haplotype analysis, the frequency of GAT haplotype was significantly higher in the UC patients than that in the controls. However, the frequency of AAT haplotype was significantly lower in the UC patients (both P < 0.01). Furthermore, the plasma levels of sTRAIL were significantly higher in the UC patients than those in the controls ((1.05 ± 0.48) vs (0.96 ± 0.90) ng/L, P < 0.01). The genetic polymorphisms of TRAIL (G1525A, G1588A, C1595T) and the plasma levels of sTRAIL are correlated with UC in Chinese patients.