Association of interleukin-18 rs1946518 gene polymorphism with the risk of the severity of enterovirus-71 infection

Abstract

Objective To examine the relationship between interleukin(IL)-18 rs1946518 gene polymorphism and severity of enterovirus 71(EV71) infection. Methods Blood samples were collected from 123 children with EV71 infection(EV71 infected group) and 52 normal control cases without EV71 infection(control group) from March 2012 to December 2014.EV71 infection was diagnosed by reverse-transcriptase polymerase chain reation(RT-PCR). The SNaPshot were used to determine genotype for A/C polymorphism at rs1946518 position of IL-18 gene. Results The frequencies of genotype AA, AC and CC in the position of IL-18 rs1946518 were 27.64%, 50.41% and 21.95% in 123 EV71 infected samples, while 26.92%, 42.31% and 30.77% in 52 control samples.No obvious significances between EV71 infected group and control group were found(P>0.05). In EV71 infected samples, the frequencies of genotype AA, AC and CC in 62 mild cases were 14.51%, 54.84% and 30.65%, while in 61 severe cases were 40.98%, 45.90% and 13.12%.Children carring AA had a higher risk to develop into severe cases(χ2=12.58, P=0.002). The frequencies of allele A and C in the position of IL-18 rs1946518 were 52.85% and 47.15% in 123 EV71 infected samples, while 48.07% and 51.93% in 52 control samples.No obvious significances between EV71 infected group and control group were found(P>0.05). In EV71 infected samples, the frequencies of allele A and C in 62 mild cases were 41.94% and 58.06%, while in 61 severe cases were 63.93% and 36.07%.Children carring allele A had a 2.455 times higher risk to develop into severe cases(χ2=11.94, P=0.001, OR=2.455, 95%CI 1.496-4.102). Conclusion The polymorphism of IL-18 rs1946518 A/C is associated with severity of EV71 infection, and the A carrier of IL-18 confer susceptibility to the severity of EV71 infection. Key words: Hand-foot-mouth disease; Gene polymorphsim; Interleukin-18; Enterovirus 71