Objectives: To determine whether cytokines and chemokines are predictive factors for baricitinib effectiveness in rheumatoid arthritis (RA).
Methods: Eleven patients were treated with baricitinib, and the levels of fractalkine/CX3CL1, CXCL16, ENA-78/CXCL5, IL-8/CXCL8, MCP-1/CCL2 and RANTES/CCL5 in serum were measured with enzyme-linked immunosorbent assays.
Results: Nine of the 11 patients successfully completed the study at 12 weeks. Two patients were excluded due to noneffectiveness of baricitinib treatment. The simplified disease activity index (SDAI) at week 12 was significantly decreased in patients receiving baricitinib compared with the SDAI at week 0 (mean ± SEM; 5 ± 1 and 15 ± 3, respectively, p<0.05). One case of herpes zoster virus infection occurred at 12 weeks. The levels of MCP-1/CCL2, RANTES/CCL5, ENA-78/CXCL5, IL-8/CXCL8, CXCL16 and fractalkine/CX3CL1 in RA serum were not significantly different before and after baricitinib treatment. Finally, we found that the level of ENA-78/CXCL5 in patients with SDAI remission was significantly higher than that in patients without SDAI remission at 12 weeks (887 ±115 pg/ml and 461 ± 102 pg/ml, respectively).
Conclusions: ENA-78/CXCL5 may be a predictor of the effectiveness of baricitinib in treating RA.