The level of serum visfatin (PBEF) is associated with total number of B cells in patients with rheumatoid arthritis and decreases following B cell depletion therapy

OBJECTIVE: Visfatin, also known as pre-B cell colony-enhancing factor, was recently characterized as a potent pro-inflammatory mediator in rheumatoid arthritis (RA). The aim of this study was to determine the effect of B cell depletion with rituximab on serum visfatin levels in patients with active RA. METHODS: We evaluated 31 patients with RA starting rituximab therapy at baseline and after 16 and 24weeks using disease activity score (DAS28). The control group consisted of 33 gender and age-matched healthy individuals. CD19(+) B cells were assessed by flow cytometry and serum levels of visfatin and B cell-activating factor of the TNF family (BAFF) were measured by ELISA at baseline and week 16. RESULTS: Total number of B cells correlated positively with serum visfatin levels (rs=0.417, P=0.025) and negatively with serum BAFF levels (rs=-0.486, P=0.008) at baseline. Serum visfatin levels were significantly higher in patients with RA compared with healthy controls (P=0.026), and significantly decreased (P=0.010), while BAFF increased (P<0.001), and both proteins became negatively correlated following treatment with rituximab (rs=-0.438, P=0.017). Visfatin levels did not correlate with the disease activity, but lack of change in the serum visfatin levels between baseline and week 16 predicted worsening disease activity between weeks 16 and 24 (rs=0.452, P=0.014). CONCLUSION: In patients with active RA, serum visfatin levels are related to the number of B cells rather than to disease activity and decrease in response to treatment with rituximab. Further studies are necessary to show if visfatin is a marker with predictive value for deterioration of RA