IL6 and rheumatoid arthritis: ACh also produces a dose-dependent inhibition of IL-6, IL-1β, and TNF-α production in human macrophages [reviewed in Pavlov and Tracey (43) and Borovikova et al. (48)] and in whole-blood of rheumatoid arthritis patients (49), whereas vagotomy leads to increases in IL-6 and, to a lesser extent, TNF-α (48).