Serum IL-35 is decreased in overweight patients with rheumatoid arthritis: its correlation with Th1/Th2/Th17-related cytokines

Background Obesity is correlated with worse drug responses and high disease activity in patients with rheumatoid arthritis (RA). Interleukin (IL)-35 is a novel anti-inflammatory cytokine that mainly produced by regulatory T (Treg). This study was performed to analyze whether IL-35 was correlated with obesity in RA and investigate the correlation between other Th1/Th2/Th17-related cytokines and obesity in RA. Results The serum IL-35 level was analyzed in RA (n = 81) and healthy donors (n = 53) by ELISA assay, and was compared between three groups (body mass index (BMI) < 18.5,>= 18.5 to 25, > 25). Serum cytokines including IL-2, IL-4, IL-10, IL-17, INF-gamma, TNF-alpha levels were measured using Flowcytometry assay. Clinical information was extracted from medical records. Serum IL-35 level in overweight patients were significantly decreased than those in lean patients. Furthermore, Th1/Th2/Th17-related cytokines from overweight patients with RA showed the characteristic immunological features. Serum IL-6, IL-17 and TNF-alpha levels were positively correlated with BMI. However, serum IL-2, IL-4, IL-10 and IFN-gamma concentrations were not correlated with BMI. Conclusions Quantitative changes in serum IL-35 level were characteristic in overweight patients with RA. These findings indicate that IL-35 plays an important role in the development of RA and may prove to be a potential biomarker of active RA.

Automated summary

The study found that serum IL-35 levels were associated with obesity in patients with rheumatoid arthritis (RA). Overweight patients with RA had significantly lower IL-35 levels compared to lean patients and showed characteristic immunological features of Th1/Th2/Th17-related cytokines.