Objective: To investigate whether three diallelic polymorphisms at the position -1082, -819 and -592 in the promoter region of the IL-10 gene were associated with diarrhea-predominant irritable bowel syndrome (D-IBS).
Methods: The IL-10 gene -1082, -819 and -592 position polymorphisms were genotyped by amplification refractory mutation systems-polymerase chain reaction (ARMS-PCR) methods in 43 patients with D-IBS and 41 healthy subjects (HS).
Results: Compared with HS, D-IBS patients had a greater frequency of T/T genotype at IL-10 gene promoter -819 position (67.4% vs 39.0%, P < 0.05), the frequencies of -819 C/T and C/C genotype were not significantly different (23.3% vs 43.9% and 9.3% vs 17.1%, P > 0.05). D-IBS patients also had a greater frequency of -592 A/A genotype compared with HS (67.4% vs 39.0%, P < 0.05), the frequencies of -592 C/A and C/C genotype were not significantly different (23.3% vs 43.9% and 9.3% vs 17.1%, P > 0.05). No significant difference was found in genotype at IL-10 gene promoter -1082 position. The -819 T allele frequency in D-IBS was significantly higher than that in control (79.1% vs 61.0%, P < 0.05), whereas -819 C allele frequency in D-IBS was lower (20.9% vs 39.0%, P < 0.05). D-IBS patients also had a greater frequency of -592 A allele compared with HS (79.1% vs 61.0%, P < 0.05), -592 C allele frequency in D-IBS was lower (20.9% vs 39.0%, P < 0.05). No significant difference was found in -1082 G or A allele frequency.
Conclusions: The presence of -819 T/T and -592 A/A genotype may be related to development of D-IBS.