[Study on the association between IL-2R and IL-7R gene polymorphism and idiopathic demyelinating optic neuritis]

To analyze the relationship between the gene polymorphism of IL-2R (rs2104286) and IL-7R (rs6897932) and the susceptibility to idiopathic demyelinating optic neuritis (IDON).

A case-control study was performed in 72 IDON patients and 81 healthy individuals as the control group. DNA was extracted from peripheral blood leukocytes. PCR was used to amplify the aim genes; the SNP of IL-2R were analyzed by restriction fragment length polymorphism (RFLP) assay and the SNP of IL-7R were analyzed by gene sequencing. The χ2 test was used to compare genotype and allele frequencies between the IDON and control populations. Odds ratio (OR) was calculated using the approximation of Woolf for the 95% confidence interval (CI).

No significant difference of genotype (χ2=0.410, P=0.815) and allele frequency(χ2=0.413, P=0.520) of IL-2R gene existed in IDON group(AA:54/AG:15/GG:3;A:123/G:21) as compared with the control group (AA:57/AG:20/GG:4;A:134/G:28). No significant difference of genotype frequency (χ2=3.787, P=0.150) of IL-7R existed in IDON group (CC:56/CT:13/TT:3) as compared with the control group (CC:52/CT:21/TT:8). However, there was a significant difference in IL-7R allele (C/T) between IDON group (C:125/T:19) and the controls (C:125/T:37) (χ2=4.743, P=0.029), OR=1.95 (95%CI: 1.07-3.55).

There is no significant difference in IL-2R rs2104286 polymorphism between IDON group and the controls; the frequencies of IL-7R rs6897932 C allele in IDON group was significantly greater than that of the controls. Polymorphism of IL-7R gene (rs6897932) may contribute to the risk of IDON.