IL6 and rheumatoid arthritis: Therefore, in this study including 376 RA patients and 463 controls, we investigated the possible association of polymorphisms in immune response genes (TNFA, IL1B, IL4, IL6, IL8, IL10, C1INH, TLR2, TLR4) and genes involved in tissue repair and apoptosis (PAI1, 5NOS2a, PARP) in relation to RA susceptibility, and with the use of anti-TNF-α therapy as selected marker of disease severity.