Background Interleukin (IL)-12, IL-23, IL-27, and IL-35 constitute a unique family of structurally-related, heterodimeric cytokines, which regulate immune response and inflammatory reactions. IL-12 family has been reported to be involved in the pathogenesis of autoimmune diseases [1-2]. However, the role of IL-12 family on Sjogren syndrome (SS) and related mechanisms remained to be elucidated.
Objectives Since the IL-12 family has been shown to regulate the generation of T regulatory 1 (Tr1) cells and Tr1 cells have been indicated a functional role in disease progress of SS through their secretion of the immunosuppressive cytokine IL-10[3-4]. The aim of the present study was to identify the specific members of IL-12 family involved in the pathogenesis of SS and to explore the relationship of IL-12 family cytokines with IL-10.
Methods 20 SS patients, 20 RA patients, 20 SLE patients and 20 healthy volunteers were recruited in the present study. Expressions of IL-12, IL-23, IL-27, and IL-35 in peripheral blood mononuclear cells (PBMCs) from patients with SS, RA, SLE and healthy controls were determined by quantitative PCR. Plasma levels of IL-12, IL-27 and IL-10 were detected by Enzyme-linked Immunosorbent Assay.
Results IL-12 and IL-27 mRNA significantly increased in PBMCs from patients with SS than healthy controls. Increased plasma levels of IL-12 and IL-27 have been confirmed in SS patients. Plasma IL-12 and IL-27 correlated with clinic indexes, such as anti-SSA, anti-SSB and ANA antibodies. IL-12 levels showed a negative correlation with plasma IL-10. However, no significant correlation was found between plasma IL-27 and IL-10 (Fig1).
Conclusions These findings suggested that IL-12 might have a pivotal role in the development and progression of SS through suppression of differentiation of IL-10-producing Tr1 cells. Therapeutic targeting IL-12 and Tr1 cells might be useful in the modulating of SS.
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Disclosure of Interest None declared