NLRP1 and Arthritis: Stimulation with TNF-α showed no effects on the NLRP1, whereas significantly upregulated the expression of NLRP3. When comparing different forms of arthritis, significantly lower expression of NLRP3 under stimulation with TNF-α was observed in the RA group compared with all other tested groups, suggesting potential contribution of altered NLRP3 activation to the etiopathogenesis of advanced RA.