The Expression And Significance Of Toll Like Receptor9,IFN-α And BAFF In Patients With Systemic Lupus Erythematosus

ObjectiveTo examine the expression of TLR9mRNA in peripheral blood mononuclearcells (PBMCs) and the level of IFN-α and BAFF in the serum of patients withsystemic lupus erythematosus. To analyze the correlation of TLR9, IFN-α and BAFFas well as SLE disease activity index(SLEDAI) in SLE patients.MethodsExpression of TLR9mRNA in peripheral blood mononuclear cells (PBMCs) of40SLE patients and20healthy controls(HC)was determined by real-time PCR. IFN-αand BAFF levels were measured in the serum of all subjects by ELISA.Results1Expression of TLR9mRNA in peripheral blood mononuclear cells wassignificantly up-regulated in SLE patients compared to HC[(1.77±0.44) vs(1.10±0.35),P<0.05].Expression of TLR9mRNA correlated positively withSLEDAI score (r=0.472,P＜0.01) and ESR（r=0.431,P＜0.05),and correlatednegatively with C3(r=-0.248,P＜0.05).2SLE patients with active disease had higher BAFF levels than that of patients withinactive disease and HC [(1141.81±650.12)pg/ml vs (652.87±414.94)pg/ml vs(573.77±241.97)pg/ml, both P＜0.01]. BAFF levels correlated positively withSLEDAI (r=0.671,P＜0.01),ESR(r=0.278,P＜0.05) but correlated negatively withC3(r=-0.32,P＜0.05).3SLE patients with active disease had higher IFN-α levels than that of patients withinactive disease and HC [5.81(9.91)pg/ml vs4.41(4.27)pg/ml vs3.89(1.18)pg/ml,both P＜0.01]. IFN-α levels correlated positively with SLEDAI(r=0.426,P＜0.05), ESR(r=0.398,P＜0.05), and correlated negatively with C3(r=-0.297,P＜0.01). 4SLE patients with positive anti-dsDNA antibody had higher levels of TLR9mRNA,IFN-α and BAFF than anti-dsDNA antibody negative ones (all P＜0.05).5Expression of TLR9mRNA in peripheral blood mononuclear cells correlatedpositively with serum IFN-α levels (r=0.509， P＜0.01) and BAFF levels(r=0.419，P＜0.01) in SLE patients. The levels of BAFF correlated positively withIFN-α levels (r=0.290, P＜0.05) in the serum of SLE patients.ConclusionUp-regulated expression of TLR9mRNA and higher levels of BAFF and IFN-αwere prominent in SLE patients, and they all correlated positively with SLE diseaseactivity. TLR9mRNA expression correlated positively with IFN-α levels as well asBAFF levels in SLE patients, in addition, BAFF levels correlated positively withIFN-α levels, suggesting TLR9mRNA，IFN-α and BAFF may interact with eachother and play an important role in maintaining the pathogenesis and disease activityof SLE.