The Clinical and Immunological Activity Depending on the Presence of Interferon gamma in Primary Sjogren's Syndrome-A Pilot Study

The upregulation of IFN pathways and their stimulated genes is associated with primary Sjogren's syndrome (pSS). The recent studies also indicate the involvement of interferon gamma (IFN gamma) in the pathogenesis of pSS. The study aimed to assess the clinical and immunological activity depending on the concentration of IFN gamma in the peripheral blood in pSS patients. Methods: The study group consisted of patients over 18 years of age with a confirmed diagnosis of pSS. Based on the collected data, disease activity was assessed using the EULAR Sjogren's syndrome disease activity index (ESSDAI) and the EULAR Sjogren's syndrome patient reported index (ESSPRI). Results: Among 40 pSS patients, 33 (82%) showed increased levels of IFN gamma. The group with positive IFN gamma was younger (43 years) than the group with negative IFN gamma (57 years) (p < 0.05). In the positive IFN gamma group, the time to diagnosis was shorter (p < 0.05). There was a difference in ESSDAI among patients with and without IFN gamma (p < 0.05). There were no differences between the groups in ESSPRI and the presence of cryoglobulins, specific anti-SSA, and anti-SSB antibodies and in C3 and C4 hypocomplementemia. RF occurred in both groups with a similar frequency (p = 0.6), but in patients with IFN gamma presence, significantly higher RF titers were observed (34.9 vs. 10.5; p < 0.05). Conclusion: In the group of patients with positive IFN gamma, the mean value of RF and ESSDAI was higher. This group was also younger than patients with pSS without IFN gamma.