Serum and salivary neopterin and interferon-gamma in primary Sjogren's syndrome - Correlation with clinical, laboratory and histopathologic features

Objective: To investigate serum and salivary neopterin and interferon-gamma as possible markers of immune system activation in primary Sjogren's Syndrome (pSS). Methods: Serum and salivary neopterin and interferon-gamma concentrations were determined in 30 untreated patients with pSS and matched with several other clinical and laboratory parameters. Results: The mean concentration of neopterin was significantly higher in pSS patients (8.12 +/- 3.36 nmol/L in serum and 9.50 +/- 7.61 nmol/L in saliva) than in normal controls (p<0.05). Significant correlations were found between serum neopterin and beta 2-microglobulin, serum IgG as well as lip biopsy score. Salivary neopterin concentration was inversely related to Shirmer-I test, tear break-up time and stimulated salivary flow rate. Serum and salivary levels of interferon-gamma were normal and no correlation with the other parameters was found. Conclusion: In pSS patients serum neopterin may represent a useful marker of cell-mediated immunity. On the other hand, salivary neopterin seems to reflect the glandular damage.