Background Sjögren's syndrome (SS) is an autoimmune disease and the treatment of SS remains symptomatic. The total glucosides of paeony (TGP) is the active compound extracted from the roots of Paeonia lactiflora Pall. TGP can reduced production of IFN-γ, IL-6 and IL-12, and inhibited dendritic cells. Recently, TGP had been approved in the treatment of rheumatoid arthritis by China State Food and Drug Administration. However, the therapeutic effects of TGP on SS and the mechanisms behind were largely unknown.

Objectives To investigate the clinical and immunological consequences of total glucosides of paeony (TGP) treatment in patients with Sjögren's syndrome (SS).

Methods Forty-five patients with primary SS participated in a randomized, double-blinded, placebo-controlled clinical trial. Patients were assigned randomly to TGP or placebo group in a ratio of 2:1 and followed up for 24 weeks. Clinical assessment was performed by EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI), stimulated and unstimulated salivary flow rate, and Schirmer test at week 4, 12, 18 and 24. The proportion of B cells and levels of serum IL-6, TNF-α, IFN-γ and BAFF were measured before and after treatment. This trial was registered on www.chictr.org, with the register number of ChiCTR-TRC-12002325.

Results ESSPRI in the patients who got 3 to 6 score at baseline was significantly reduced in TGP group at 18- and 24-week changed from (4.81±0.60) to (4.15±1.27) (P=0.012) and (4.20±1.46) (P=0.027). Stimulated salivary flow rate increased at week 24 from (1.80±0.39) to (2.01±0.51) (P=0.031) and unstimulated salivary flow rate increased from (1.30±0.92) to (1.55±0.90) (P=0.011) in TGP group, but the placebo group showed no significant difference. Erythrocyte sedimentation rate (ESR) was decreased significantly compared to the placebo group at 12- and 24-week from (40.9±18.0) to (29.4±12.2) (P=0.003) and (30.4±17.3) (P=0.024). The percentage of naive B cells decreased in TGP group from (77.34±12.20)% to (64.59±15.60)% (P=0.005) while memory B cells increased at week 24 from (21.79±11.97)% to (34.21±15.48)% (P=0.006). The concentrations of TNF-α and IFN-γ decreased in TGP group at week 24 from (32.51±26.67) to (24.22±13.56) (P=0.017) and (10.71±8.94) to (6.55±4.88) (P=0.022), respectively.

Conclusions TGP appears to improve the glandular secreting function and ameliorate the inflammatory process.

Acknowledgement We thank the patients who participated in the study and Lansen Pharmaceutical Co. Ltd. (Shenzhen, China) which kindly provided drugs. This work was funded by a grant from the National Nature Science Foundation of China (No. 81373187) and the Clinical Research Special Foundation of Chinese Medical Association (12040730373).

Disclosure of Interest None declared