Background Dysfunction of peripheral immune tolerance against self antigens is a critical factor in the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) and is mainly mediated by T regulatory cells (Tregs).
Objectives Aim of the present study was the evaluation of Tregs and related cytokines (IL-6, IL-10, TGF-β) in regard to disease activity in NPSLE patients.
Methods Twenty patients (17 females, 3 males, mean age 44.9±14.1 years, mean disease duration 87.2±63.4 months) were included. CD4+CD25highFOXP3+ Tregs were assessed by triple color flow cytometry in 88 peripheral blood samples (26 active, 62 inactive disease). IL-6, IL-10 and TGF-β were evaluated by ELISA in 36 serum samples (18 active, 18 inactive disease). Disease activity was determined using SLEDAI (SLE Disease Activity Index). Statistics were performed by Student's t-test; p<0.05 was considered significant.
Results Tregs were significantly lower in active NPSLE (0.57±0.17% of CD4+ T cells vs 1.05±0.39%, absolute numbers 4.6±3.4 vs 9.3±6.6 cells/mm3, p<0.001). Serum IL-6 was significantly higher in active disease (6.1±2.4pg/ml vs 2.8±3pg/ml, p=0.005). On the contrary, IL-10 levels were not differentiated (4.5±3.2pg/ml vs 2.75±3.77pg/ml, p=0.224), while TGF-β was marginally lower in active disease (20064±5495pg/ml vs 25770±9282pg/ml, p=0.103).
Conclusions Peripheral Tregs are lower in active NPSLE, in parallel with higher IL-6 and lower TGF-β levels. Impairment of the IL-6/TGF-β axis probably plays an important role in disease pathogenesis.
Disclosure of Interest None declared