Polymorphism of OAS2 rs739901 C/A Involves the Susceptibility to EV71 Infection in Chinese Children.

This study aimed to assess the relationship of OAS2 rs739901 5,-flanking C/A polymorphisms with the susceptibility to Enterovirus-71 (EV71) infection. We investigated 294 hand-foot-mouth disease (HFMD) Chinese children with EV71 infection (165 mild cases and 129 encephalitis cases). The improved multiplex ligation detection reaction (iMLDR) technique was used to test the genotypes. In EV71-infected patients, the CA genotype distribution (P=0.007), A allele frequency (OR 1.32,95% CI 1.0-1.7, P=0.034) and CA+AA carriage frequency (P=0.003) of OAS2 rs739901 5'-flanking were obviously elevated as compared with controls, but there were no statistically significant differences between mild cases and encephalitis cases. In EV71-infected patients, the counts of white blood cells (P=0.034) and blood glucose concentrations (P=0.042) were raised in A carriers (CA+AA). Among different genotypes of encephalitis cases, the contents of cerebrospinal fluid (CSF) showed no significant differences. IFN-γ levels in EV71-infected patients were higher than those in controls (mild group vs. control group, P<0.01; encephalitis group vs. control group, P<0.01;). In encephalitis cases, IFN-γ levels were reduced (P<0.05) in A carriers compared to CC genotype, however, there were no significant differences between genotypes CA and AA (P=0.226). These findings suggest that OAS2 rs739901 5'-flanking C/A genetic polymorphisms involve the susceptibility to EV71 infection, and A allele might be a risk factor of the susceptibility to EV-71 infection.

Association of Toll-like receptor 3 gene polymorphism with the severity of enterovirus 71 infection in Chinese children.

Enterovirus 71 (EV71) infection has become one of the major threats to children globally in recent years. Toll-like receptor 3 (TLR3) plays an essential role in host defense against EV71 infection. This study was designed to assess the possible association between the TLR3c.1377C/T polymorphism and disease severity in Chinese children with EV71 infection. The TLR3c.1377C/T gene polymorphism was identified in EV71-infected patients (n = 177), including mild cases (n = 99) and severe cases (n = 78) as well as healthy controls (n = 225), using improved multiplex ligation detection reaction (iMLDR) technology. Serum levels of IFN-γ and IL-4 were measured using enzyme-linked immunosorbent assays. The presence of the TT genotype (p = 0.030) and the T allele (OR, 1.8; 95% CI, 1.2-2.8; p = 0.010) was significantly more frequent in severe cases. The plasma levels of IFN-γ and the IFN-γ/IL-4 ratio were significantly lower with the TT (102.0 ± 24.2 pg/mL, p < 0.01 and 14.2 ± 2.8, p < 0.001) and CT genotypes (114.1 ± 26.2 pg/mL, p < 0.05 and 18.0 ± 3.1, p < 0.001) than with the CC genotype (135.5 ± 36.8 pg/mL and 24.9 ± 4.7), but the plasma levels of IL-4 with the TT (7.3 ± 1.7 pg/mL, p < 0.01) and CT genotypes (6.4 ± 1.3 pg/mL, p < 0.05) were significantly higher than with the CC genotype (5.5 ±1.3 pg/mL). These findings suggest that the TLR3c.1377T allele is associated with susceptibility to severe EV71 infection in Chinese children.