The cytokine profile (IL-1β, IP-10, IL-29, GM-CSF, IFN-α2, IFN-β, TGF-β1, MPC-1, TNF-α, IFN-γ, IL-6, IL-10, IL-17A, IL-12p70, IL-2, and IL-4) of RA patients’ saliva was evaluated using flow cytometry and benchmarked with their levels in saliva of healthy controls and patients with other rheumatic diseases. Here, MPC1 is linked to rheumatoid arthritis.