Association between IFN-α and primary Sjogren's syndrome

ObjectiveTo determine the level of IFN-α in labial salivary glands, plasma, and peripheral blood cells from patients with primary Sjogren's syndrome (pSS).MethodsLabial salivary gland biopsy specimens, plasma, and peripheral blood cells from patients with pSS were investigated. The IFN-α–positive cells, measurable IFN-α level, and IFN-α gene mRNA level were determined by using immunohistochemistry, ELISA, and real-time PCR, respectively. Statistical analysis was performed by Student t test or Fisher's exact test.ResultsAbout 60% of patients (22/37) with pSS had significantly higher scores of IFN-α–positive cells in labial gland biopsy and most IFN-α–positive cells were localized predominantly in the lymphocytes and ductal epithelial cells. But in 3 of the control samples (3/24), the IFN-α–positive cells existed only in the ductal epithelial cells with lower scores. Forty-three percents of the patients with pSS were found with detectable IFN-α concentration in plasma (≥12.5 pg/mL), and their concentration was higher than that of control group. Furthermore, the IFN-α mRNA levels in peripheral blood cells were up-regulated in the patients with pSS.ConclusionNo matter in labial salivary glands or hematoplasma, or peripheral blood cells, IFN-α expression levels are up-regulated in patients with primary Sjogren's syndrome.