IL6 and rheumatoid arthritis: Moderate-to-strong correlations between cytokines of Th1 cell (IL-2, IFN-γ, GM-CSF), Th2 cell (IL-4, IL-6, IL-10), monocyte/macrophage (IL-1β, IL-6, IL-12, TNF, G-CSF), and fibroblast (IL-7) origin were observed in the total cohort of RA patients.