Cytokine concentrations in stimulated whole saliva among patients with primary Sjögren's syndrome, secondary Sjögren's syndrome, and patients with primary Sjögren's syndrome receiving varying doses of interferon for symptomatic treatment of the condition: A preliminary study

Sjögren's syndrome is an autoimmune disorder which causes diminished salivary flow due to autoimmune sialoadenitis. This decrease in saliva flow is the result of inflammation and atrophy of the salivary glands. Most treatment regimens are palliative in nature, but treatment with interferon (IFN) holds promise for Sjögren's syndrome sufferers. Several studies have investigated cytokine concentrations in the salivary glandular tissues from Sjögren's syndrome patients; however, there is little information concerning cytokine expression in saliva. This is especially true with respect to treatment modalities and their effects on local cytokines. A clinical study was conducted to determine salivary interleukin (IL)-6, IFN, and IL-2, concentrations among subjects diagnosed with primary and secondary Sjögren's syndrome and a healthy control group. The primary Sjögren's syndrome showed significantly higher salivary IL-2 and salivary IL-6 than the control and secondary Sjögren's groups. There were no between group differences for salivary IFN concentrations. In addition, the study assessed salivary IL-6, IFN, and IL-2 concentrations among 18 Sjögren's syndrome patients before and after administration of IFN via the oral mucosal route. The results of the study showed that the mean values for the pre- and post-treatment groups for stimulated whole saliva flow rates were 3.15 and 3.74 ml/5 min, respectively. The post-treatment group exhibited a 16.8% increase in stimulated whole saliva flow rates. The salivary IL-6 concentration was 53.3% lower for the post-treatment group (17.79) as compared to the baseline value (33.35). The values for salivary IFN and salivary total protein were virtually unchanged from their baseline values. Salivary IL-2 values, however, were 50% lower in the post-treatment group (3.07) when compared to their respective baseline values (6.10). The results of this study suggest that healthy individuals exhibit lower salivary IL-2 and IL-6 as compared to individuals suffering from primary and secondary Sjögren's syndrome. The results also suggest that administration of IFN via the oral mucosal route may increase salivary flow rates and depress certain cytokines (IL-2, IL-6) associated with inflammatory destruction of salivary glandular tissues in Sjögren's syndrome patients.