Role Of VSTM1-v2 In Primary Sjogren's Syndrome

ObjectivesPrimary Sjogren's syndrome?pSS?was a chronic inflammatory autoimmune disease mainly involving exocrine glands,and the pathogenesis remained unclear.Studies had shown that Th17 cells were one of the key factors in the pathogenesis of pSS,and the transformation of Th17/Treg cells balance to the axis of proinflammatory Th17 cells exacerbated pSS.IL-17A was primarily produced by Th17 cells,and the levels of IL-17A cytokines were increased in patients with pSS,which were associated with disease activity and severity.V-set and transmembrane domain inclusion 1?VSTM1?was identified as a novel soluble cytokine and a potential leukocyte differentiation antigen gene by immunogenomic analysis.VSTM1-v2 promoted the differentiation of Th17 cells and the secretion of IL-17A,so we speculate that VSTM1-v2 might play a role in the pathogenesis of pSS.This study was designed investigate the correlation between VSTM1-v2 and IL-17A expression,and the association with serological markers related to pSS disease activity,and to explore the possibility of VSTM1-v2 as a biomarker for pSS,and to provide new ideas for further study of the pathogenesis of pSS.Methods1.79 patients with pSS and 50 age-and gender-matched healthy controls that met the inclusion criteria were selected.2.PBMCs were obtained by standard Ficoll density gradient centrifugation.Total RNA was extracted from PBMCs by Trizol method.Total RNA quality was assessed by 1%agarose gel electrophoresis and spectrophotometry.3.Reverse transcription of RNA into cDNA by PCR amplification?pre-denaturation,denaturation,annealing,extension,terminal extension?.The amplified products were detected by quantitative real-time PCR?qPCR?,and specific amplified products were identified by amplification curve and dissolution curve analysis.The mRNA expression levels of VSTM1-v2 and IL-17A in PBMCs were analyzed by 2^-??Ct.4.The disease activity parameters of patients with pSS were measured by ESSDAI assessment proposed by the European League Against Rheumatism?EULAR?and routine methods.The ANA in serum was measured by indirect immunofluorescence,and the anti-SSB,anti-SSA and anti-RO52 in serum were determined by immunoblotting.ESR was measured by manual.And specific proteins such as CRP and IgG were measured by BNII automatic protein analyzer-scattering turbidimetry.5.The differences between VSTM1-v2 mRNA and IL-17A mRNA expression levels in patients with pSS and healthy controls were analyzed by statistical analysis software GraphPad Prism 5.01.The correlation between the expression levels of VSTM1-v2 mRNA and IL-17A mRNA,ESSDAI,ESR,CRP,IgG,ANA,anti-SSB,anti-SSA and anti-RO52 in patients with pSS were analyzed by statistical method too.P<0.05 was considered statistically significant.Results1.Compared with healthy controls,the expression level of VSTM1-v2mRNA?P=0.0040?in PBMCs of patients with pSS was significantly increased.2.Compared with healthy controls,the expression level of IL-17A mRNA?P=0.0412?in PBMCs of pSS patients was increased.3.The expression level of VSTM1-v2 mRNA in pSS patients was positively correlated with IL-17A mRNA expression level?r=0.2781,P=0.0131?.4.VSTM1-v2 mRNA expression level in patients with pSS was positively correlated with ESSDAI?r=0.3662,P=0.0009?,ESR?r=0.2606,P=0.0204?,CRP?r=0.3233,P=0.0037?and IgG?r=0.2880,P=0.0129?.5.VSTM1-v2 mRNA expression level in patients with pSS was no correlation with ANA?r=0.0167,P=0.8832?,anti-SSB?r=-0.0345,P=0.7626?,anti-SSA?r=-0.0615,P=0.5900?and anti-RO52?r=-0.0237,P=0.8356?.ConclusionsThe expression levels of VSTM1-v2 and IL-17A were increased in PBMCs of pSS patients,and the expression of VSTM1-v2 was associated with pSS disease activity.VSTM1-v2 might participate in the pathogenesis of pSS by promoting the secretion of IL-17 A,which might be a new cytokine.involved in the pathogenesis of pSS.