Genetic polymorphisms of interleukin 8 and risk of ulcerative colitis in the Chinese population

BackgroundInterleukin-8 (IL-8), a CXC chemokine that recruits and activates inflammatory cells, plays a critical role in the pathogenesis of ulcerative colitis (UC). There are no studies on the association of single nucleotide polymorphisms (SNPs) of the IL-8 gene with the risk of UC.MethodsAll 162 unrelated UC patients and 203 control subjects were analyzed for 5 IL-8 SNPs ((− 845 (T/C), − 738 (T/A), − 353 (A/T), − 251 (T/A) and + 678 (T/C)) using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay and PCR-sequence-specific primers (SSP) method. Serum IL-8 concentrations were measured in all subjects.ResultsIndividual SNPs were not associated with risk for UC. However, the frequency of − 353A/− 251A/+ 678T haplotype was significantly higher in UC patients than in healthy controls (OR = 1.454, p = 0.036). By subgroup analyses, this haplotype tended to be more common in severe UC patients than in those with mild-to-moderate disease (OR = 2.281, p =  0.027). Furthermore, patients with AAT diplotype showed significantly increased serum IL-8 concentrations than those with other diplotypes (p < 0.001).ConclusionThese results suggest that IL-8 is a novel susceptibility gene to UC in Chinese UC patients, and furthermore, that IL-8 polymorphisms may be related to severe clinical subtype of UC.