Objective: To investigate the association of SNP of CD40 gene and its serum levels with ischemic stroke (IS).
Methods: A total of 202 IS patients from a hospital of Baise city were enrolled in case group from May 2013 to November 2014. At the same time, 109 healthy people who had physical check-ups in the outpatient department at the same hospital were enrolled in the control group. All participants were from Guangxi Zhuang Autonomous Region and unrelated to each other. 3 ml venous blood were collected on the premise of informed consent. The single nucleotide polymorphisms of CD40 gene rs1883832 C/T, rs13040307 C/T, rs752118 C/T and rs3765459 G/A were analyzed using a Snapshot SNP genotyping assays, and the serum levels of CD40 were tested by ELISA. t-test was used to compare the serum levels of CD40 between the case and control group, and the genotypes at different locuses in case group; χ(2) test was used to compare the distribution differences of the CD40 gene locuses in different genotypes and allele between the case group and the control group; alleles was established as independent variables, the occurrence of the IS as dependent variable, and expressed relative risk with OR (95%CI) value.
Results: In the case group, the frequency of CC, CT and TT genotypes in CD40 gene rs1883832 C/T were 21.78% (44/202), 49.51% (100/202) and 28.71% (58/202), respectively, and 33.17% (66/199), 48.74% (97/199), 18.09% (36/199) in the control group, respectively, the differences between the two groups was significant (χ(2)=9.57, P=0.008). The CD40 serum levels were (62.7 ± 24.5) pg/ml in the case group, which was higher than that in the control group (45.3 ± 17.2) pg/ml (t=8.97, P<0.001). The serum levels of TT and CT genotypes in CD40 gene were (65.9 ± 26.3) and (64.3 ± 25.9) pg/ml, respectively, and the differences were significant when comparing with CC genotype (t equaled 5.34 and 5.03, respectively, P<0.001). The risk of developing IS was 1.56 times higher in 1883832 T allele carriers than that in rs1883832 C allele carriers (OR=1.56, 95% CI: 1.18-2.06); Combined genotype analysis displayed that CD40 gene rs1883832 C/T, rs13040307 C/T, rs752118 C/T and rs3765459 G/A polymorphisms showed strong linkage disequilibrium, the case group TCCA haplotype was tested to be associated with a significantly increased risk of IS as compared with that in the control group(OR=2.49; 95%CI: 1.13-5.48).
Conclusion: CD40 gene rs1883832 C/T polymorphism and its TCCA haplotype were possibly associated with ischemic stroke, and the susceptibility gene for ischemic stroke may be rs1883832 T allele.