Objective: To determine the level of IFN-alpha in labial salivary glands, plasma, and peripheral blood cells from patients with primary Sjogren's syndrome (pSS).
Methods: Labial salivary gland biopsy specimens, plasma, and peripheral blood cells from patients with pSS were investigated. The IFN-alpha-positive cells, measurable IFN-alpha level, and IFN-alpha 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.
Results: About 60% of patients (22/37) with pSS had significantly higher scores of IFN-alpha-positive cells in labial gland biopsy and most IFN-alpha-positive cells were localized predominantly in the lymphocytes and ductal epithelial cells. But in 3 of the control samples (3/24), the IFN-alpha-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-alpha concentration in plasma (> or = 12.5 pg/mL), and their concentration was higher than that of control group. Furthermore, the IFN-alpha mRNA levels in peripheral blood cells were up-regulated in the patients with pSS.
Conclusion: No matter in labial salivary glands or hematoplasma, or peripheral blood cells, IFN-alpha expression levels are up-regulated in patients with primary Sjogren's syndrome.