To determine the relationship between serum G-CSF, RA disease activity and the levels of inflammatory cytokines.
Sixty-one patients (5 men and 56 women; mean age; 56.1 +/- 11.4 [+/- SD] years, range, 22-70 years) who were selected at random and met the American College of Rheumatology criteria for RA were examined. Granulocyte-colony stimulating factor (G-CSF) levels in sera and synovial fluid were measured by solid-phase radioimmunoassay (RIA). We also measured various indices of RA disease activity and serum levels of IL-1 beta, IL-6 and TNF-alpha by ELISA.
The morning stiffness, number of tender or swollen joints, ESR, Lansbury index and serum G-CSF levels in patients with active RA were significantly higher than the corresponding levels in patients with inactive RA. Serum G-CSF levels correlated significantly with morning stiffness, the number of tender or swollen joints and the Lansbury index. However, there was no correlation between serum G-CSF and ESR. High levels of IL-1 beta, IL-6 and TNF-alpha were detected in RA patients. The number of tender or swollen joints, ESR, Lansbury index, and IL-1 beta were significantly higher in G-CSF-positive RA patients than in G-CSF-negative RA patients.
Our results suggest that G-CSF produced by synovial cells stimulated by inflammatory cytokines might contribute to inflammatory arthritis in RA patients.