Correlation between albumin to fibrinogen ratio, C-reactive protein to albumin ratio and Th17 cells in patients with rheumatoid arthritis

Background: The albumin to fibrinogen ratio (AFR) and the C-reactive protein to albumin ratio (CAR) have been served as inflammatory markers. However, their roles in RA remain unclear. We investigated the association of AFR/CAR with the concentration of autoantibodies and Th17 cells in RA.

Methods: A total of 196 RA patients, 200 patients with systemic lupus erythematosus (SLE), and 200 healthy donors (HD) who were admitted to the First Affiliated Hospital of Fujian Medical University were enrolled. The results of FIB, ALB, CRP, anti-cyclic citrullinated peptide antibodies (anti-CCP), rheumatoid factor (RF) and erythrocyte sedimentation rate (ESR) from RA patients and SLE patients were retrospectively analyzed. The percentage of Th17 cells in peripheral blood of RA patients was detected by flow cytometry, and the relative expression of TNF-α, IL-6 and IL-17A was detected by RT-qPCR. Correlation analysis of AFR/CAR and Th17 cells, CRP, ESR, TNF-α, IL-6 and IL-17A in RA was conducted.

Results: Compared with SLE patients and healthy donors (HD), AFR concentration was significantly lower (P < 0.01) in RA patients, while CAR concentration was significantly increased (P < 0.01) in RA patients. AFR showed negative correlation with CRP (r = -0.7103), ESR (r = -0.6542), RF (-0.2219), Th17 cells (r = -0.5952) and IL-17A (r = -0.4681). CAR was positively correlated with CRP (r = 0.9899), ESR (r = 0.605), RF (0.1867), Th17 cells (r = 0.6818), TNF-α (r = 0.3388), and IL-17A (r = 0.2046).

Conclusions: The concentration of AFR in RA patients was reduced, while CAR concentration was increased. AFR and CAR are associated with CRP, ESR, RF, and Th17 cell ratios in RA patients, which can be used as potential indicators for determining RA inflammation.