The −174G/C and −572G/C Interleukin 6 Promoter Gene Polymorphisms in Mexican Patients with Rheumatoid Arthritis: A Case-Control Study

Abstract

Objective. There is a lack of information about the genotype frequencies of IL-6 −174G/C and −572G/C polymorphisms in Mexicans with rheumatoid arthritis (RA). Therefore, the aim of this study was to evaluate the association of the IL-6 −174G/C and −572G/C polymorphisms in Mexican mestizo with RA. Methods. We included 137 patients with RA and 102 healthy controls. Patients were assessed for clinical characteristics. IL-6 −174G/C and −572G/C polymorphisms were genotyped using PCR-RFLP analysis. Allele and genotype frequencies and the Hardy-Weinberg equilibrium were computed. Odds ratios (ORs) were computed to identify the risk for RA associated with the presence of GG genotype in comparison with the GC or CC genotypes. Results. The genotype −174GG occurred at a higher frequency in cases and controls (77.4% versus 78.4%, P = 0.845). We found similar results for the genotype −572GG (54% in patients versus 60.8% in controls, P = 0.295). Conclusions. This is the first study to evaluate the association of −174G/C and −572G/C polymorphisms of the IL-6 gene with RA in Mexican mestizo patients. These two polymorphisms were not associated with RA in the studied sample. Additional studies are required to evaluate if these IL-6 polymorphisms have relevance to the development of more severe disease.

Assessment of the −174G/C (rs1800795) and −572G/C (rs1800796) Interleukin 6 Gene Polymorphisms in Egyptian Patients with Rheumatoid Arthritis

“…Our results were in agreement with Zavaleta-Muñiz et al, 2013 who found no significant differences in allele or genotype frequencies of this polymorphism between RA and controls. But in contrast to our results, they found that the GG genotype was the most frequently observed genotype in the Mexican mestizo population among patients with RA and healthy controls (54% and 60.8% respectively) [7]. Also, Li et al, 2014a observed no association for IL-6 −572G/C gene polymorphism and RA in Chines Han population.…”

“…On the other hand, our results were against different studies in which they found no differences in allele or genotype frequencies of IL-6 −174G/C gene polymorphism between RA and controls in a different population such as Mexican and Turkish populations [7, 8]. The controversy of results may be due to different origin or ethnicity.…”

“…Among the polymorphic sites described in the IL-6 gene promoter, there are two biallelic polymorphisms that may be associated with differences in cytokine production: −174G/C (rs1800795) and −572G/C (rs1800796). These polymorphisms consist of a single nucleotide change from guanine (G) to cytosine (C) at positions −174 and −572 in the promoter region, respectively [7]. IL-6 promoter polymorphisms have been associated with susceptibility to RA, however, conflicting results were observed in different populations [8, 9].…”

Association between -174G/C and -572G/C interleukin 6 gene polymorphisms and severe radiographic damage to the hands of Mexican patients with rheumatoid arthritis: a preliminary report

“…A study assessing the frequency of the -174G/C polymorphism in the IL6 gene showed that the -174G/G genotype of IL6 was more prevalent in RA compared with the CC and GC genotypes (Zavaleta-Muñiz et al, 2013). Our results are in accordance with the findings described by Gao et al (2015), who conducted a meta-analysis comparing the frequency of the IL6 gene -174G/C polymorphism in different populations with sepsis and healthy controls, where was reported that GG was the most frequent genotype in the control group.…”

“…The genotyping of the -174G/C and -572G/C polymorphisms was performed by trained personnel blinded to the patients' clinical characteristics. The genotypes were screened by an approach based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and SfaNI and BsrBI restriction endonucleases were used for the -174G/C and -572G/C polymorphisms, respectively, as described elsewhere (Zavaleta-Muñiz et al, 2013). The resulting fragments were analyzed by electrophoresis on a 6% polyacrylamide gel stained with silver nitrate.…”