Abstract
Purpose :
Cytokine-related genes are assumed to be key players in dry eye syndrome (DES) and Sjogren’s syndrome (SS) pathogenesis. However the association between specific genes variants and both DES and SS are unclear, and comparisons between these two diseases has not yet been performed. In this study we compared single nucleotide polymorphism (SNP) variation in genes encoding cytokine levels among SS and DES patients in Israel.
Methods :
A total of 180 subjects were recruited, 82 with SS and 98 with DES. Using a candidate gene approach and allele-specific PCR technique for genotyping, the proportions of risk alleles in TNFα (rs1800629), IL10 (rs1800896) and TNFAIP3 (rs2230926) SNPs were compared between study groups.
Results :
The allelic distribution of the study groups was found to be very similar and match to Caucasians (CEU – Northern Europeans from Utah) population distributions in these SNPs. While none of the SNPs variants were found to be statistically significant associated to SS or DES in a recessive model, in an additive model the TNFα (rs1800629)-G risk allele was found among a higher proportion of SS patients compared to DES (Homozygote-G: 70.8% vs. 64.7%; Heterozygote: 26.9% vs. 11.2%, respectively, p=0.02). After adjusting for possible confounders, none of the tested SNPs were associated with SS compared to DES.
Conclusions :
The frequency of IL10 (rs1800896-A) and TNFAIP3 (rs2230926-G) alleles was not found differ significantly between SS and DES patients. These findings may be due to limited power of the sample size of 180 participants. The TNFa (rs1800629-G) SNP seems to be associated with SS in an additive model. TNFa protein levels are known to be associated with inflammation, outcome of infection, and susceptibility to autoimmune diseases such as SS. The gene has also been associated with non-Hodgkin lymphoma, a serious complication of SS. Further comparison to healthy controls is required, as well as exploring other SNPs variants relating to the immune pathway in order to understand the genetic basis of DES and SS etiology.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.