Th17 Cells In Primary Sjogren's Syndrome

Background. Primary Sjogren’s syndrome (pSS) is an autoimmune disease which is characterized with both lymphocytes infiltration and dysfunction of exocrine glands. pSS often result in xerostomia and xerophthalmus. Th17cell is a newly defined subgroup of T helper cell and is considered critical to the development of many autoimmune diseases. IL-17A is the main cytokine that Th17cell secretes. Th17cell plays an important role in the pathogenesis of pSS. Thus, this study analyzed the Th17cell response in peripheral blood from patients with pSS, systemic lupus erythematosus (SLE) and healthy subjects. Objective. To investigate the expression of CD4+IL-17+Th17cell in the peripheral blood, serum levels of IL-17A, IL-6and IL-1β, and the expressions of IL-17A mRNA and IL-17F mRNA of patients with primary Sjogren’s syndrome (pSS). We have patients with SLE as disease controls and healthy people as healthy controls (HC). Then analyze the correlations beween these examines and clinical indictors.Methods. Samples of peripheral venous blood were collected from87diagnosed pSS patients,9diagnosed SLE patients and42HC. We classified pSS patients who had corticosteroid or immunosuppression therapy for no longer than three months as untreated pSS and pSS patients who had corticosteroid or immunosuppression therapy for more than three months as treated pSS. The level of Th17cell in the peripheral blood was measured by flow-cytometric assay. The serum levels of IL-17A, IL-6and IL-1β were tested with ELISA kits. The levels of IL-17A mRNA and IL-17F mRNA were tested by RT-PCR. The clinical indictors including IgG, IgA, IgM, C3, C4, CH50, EULAR Sjogren’s Syndrome Disease Activity Index (ESSDAI), focus score (FS), ESR, hsCRP, age and disease duration were collected to analyze the correlations.Results.1. The level of Th17cell in the peripheral blood of pSS patients was significantly higher than that of HC (1.65±1.18%vs1.22±0.71%, p<0.05) and higher than that of SLE patients (1.65±1.18%vs1.44±0.87%, p=0.622). The level of Th17cell in the peripheral blood of untreated pSS patients was higher than that of treated pSS patients (1.89±1.17%vs1.42±1.16%, p=0.082). The level of Th17cell of pSS patients was significantly positively correlated with the level of hsCRP (r=0.711, p=0.021). 2. The serum level of IL-17A of pSS patients was significantly higher than that of HC (2.34±3.54pg/ml vs0.39±0.65pg/ml, p=0.012) and higher than that of SLE patients (2.34±3.54pg/ml vs0.86±1.08pg/ml, p=0.347). There were no statistical differences between untreated pSS patients and treated pSS patients (2.41±4.04pg/ml vs2.22±2.68pg/ml, p=0.889). The serum level of IL-17A of untreated pSS patients was significantly positively correlated with the level of hsCRP (r=0.785, p=0.012). The serum level of IL-6of pSS patients was higher than that of HC (6.79±8.76pg/ml vs2.93±1.62pg/ml, p=0.182) and higher than that of SLE patients (6.79±8.76pg/ml vs4.81±2.43pg/ml, p=0.450). The serum level of IL-1β of pSS patients was higher than that of HC (5.50±8.10pg/ml vs3.51±4.41pg/ml, p=0.352) and significantly higher than that of SLE patients (5.50±8.10pg/ml vs1.28±1.60pg/ml, p=0.014).3. The level of IL-17A mRNA in the peripheral blood of pSS patients was higher than that of HC (1.32±2.73vs0.37±0.28, p=0.559) and significantly higher than that of SLE patients (1.32±2.73vs0.41±0.91, p=0.010). The level of IL-17A mRNA in the peripheral blood of untreated pSS patients was significantly higher than that of treated pSS patients (1.74±3.26vs0.58±1.21, p=0.024). The level of IL-17F mRNA in the peripheral blood of pSS patients was higher than that of HC (1.02±0.84vs0.66±0.91, p=0.234) but lower than that of SLE patients (1.02±0.84vs1.16±0.81, p=0.697).4. The level of Th17cell of pSS patients was significantly positively correlated with the serum level of IL-17A (r=0.433, p=0.027). ESSDAI was significantly positively correlated with the serum level of IgG (r=0.253, p<0.05). ESSDAI was not correlated with the level of Th17cell.Conclusion. The levels of Th17cell, IL-17A mRNA and IL-17F mRNA in the peripheral blood and the surum level of IL-17A of pSS patients were higher than those of HC. The levels of Th17cell, IL-17A mRNA and IL-17F mRNA in the peripheral blood and the surum level of IL-17A of untreated pSS patients were higher than those of treated pSS patients. The levels of Th17cell, IL-17A mRNA in the peripheral blood and the surum level of IL-17A of pSS patients were higher than those of SLE patients. The surum levels of IL-6and IL-1β of pSS patients were higher than those of SLE patients and HC. ESSDAI was significantly positively correlated with the serum level of IgG. But ESSDAI was not correlated with the level of Th17cell.