Study On MRNA Expression Of IL-28RA In Peripheral Blood Mononuclear Cells Of SLE Patients

Background Systemic lupus erythematosus(SLE) is a systemic autoimmune and inflammatory disease with a strong genetic contribution and characterized by kinds of immune reactions. It affects mainly women. The pathogeneses of SLE are still not sure. Extensive researches showed genetic, endocrine, infection, immune abnormalities and some environmental factors correlated with the incidence of SLE. Among them, genetic factors play an important role in the pathogenesis of SLE. Over the past 20 years, genetic linkage and association studies by many research groups showed a large number of susceptible SLE gene, such as HLA, STAT4, IRF5, ITGAM and PTPN22 etc. With the development and the completion of human single pattern program(Human Haplotype Map, Hap Map) and the use of high-throughput, high efficiency and cheap genotyping experiment technology since 2008, genome-wide association study(Genome-wide association study, GWAS) among different races of SLE patients found more than 40 susceptibility genes. In 2013, a genome-wide association study identified IL-28 RA as a susceptibility gene for SLE. The protein encoded by IL-28 RA belongs to the class II cytokine receptor family and forms a receptor complex with interleukine 10 receptor, beta(IL10RB). The receptor complex has been shown to interact with type Ⅲ interferons with overexpressing of IL-28 RA, resulting in enhancing the response to IL28 A and IL29, while decreasing the response to IL28 B.Objective To investigate the different expression levels of IL-28 RA in peripheral blood mononuclear cells(PBMCs) from SLE patients and healthy controls and the association between IL-28 RA expression and SLEDAI or the variant of the single-nucleotide polymorphism(SNP) rs4649203.Method We performed a quantitative reverse transcription polymerase chain reaction(RT-PCR) in 62 patients with SLE and 69 controls. Sequenom Mass Array system was used to genotype SNP(rs4649203). Differences in IL-28 RA m RNA expression levels in PBMCs between patients with SLE and healthy controls were determined by the nonparametric Mann-Whitney rank sum test. The genotype frequency of SNP rs4649203 was tested for Hardy-Weinberg equilibrium in cases and controls(with all P values >0.05), separately. Genotypes were compared using the Independent-Samples T test. Spearman’s correlation coefficient rank test was used to assess the association between IL-28 RA m RNA expression levels and the SLEDAI scores. Analysis was performed with Statistical Package for the Social Science(SPSS) version 20.0. Data were expressed as mean ± standard deviation. P value < 0.05(two-tailed) was considered to be statistically significant.Results The expression levels of IL-28 RA m RNA in SLE patients were significantly increased compared with those of healthy controls. But there were no significant differences between the expression levels of IL-28 RA and SLEDAI or the variant of the SNP rs4649203.Conclusion These results indicated that IL-28 RA m RNA may be correlated with the pathogenesis of SLE.