TNF and rheumatoid arthritis: We next investigated whether cytokines known to play key roles in the pathogenesis of RA and to have the capacity to activate SF, namely TNFα, IL-1β and IL-17A, and IFNγ, which we found in highest concentrations in ThCM, are known to play a role in the pathogenesis of RA or other rheumatic diseases, alone or in combination, are able to induce the production of lactate by SF.