IL6 and rheumatoid arthritis: After observing the way in which joint destruction and levels of proinflammatory cytokines in the serum or arthritic tissues of RA patients are positively related, researchers identified that a range of proinflammatory cytokines, including tumour necrosis factor- (TNF-) α, interleukin- (IL-) 1β, and IL-6, perform a significant function in the condition's biological process [3].