Proinflammatory cytokines in lymph fluid of patients with rheumatoid arthritis

The objective of investigation was to study the concentration of proinflammatory cytokines in lymph fluid drained from the joint tissues involved in the inflammatory process. The levels of proinflammatory cytokines IL-1 beta and IL-6 were several fold higher in lymph than in blood samples of patients with rheumatoid arthritis. The level of TNF alpha and IL-8 was also higher in lymph than in peripheral blood. The levels of IL-1 Ra and IL-10 were significantly elevated both in lymph and blood of rheumatoid patients as compared to controls. Since levels of cytokines were higher in lymph than serum and also in some cases serum levels remained normal, it seems that measuring cytokine level in lymph gives a better insight into the intensity of the local inflammatory process than measuring serum levels.