However, mice papilla mimicked the phenotype of microlithiasis-induced acute pancreatitis in humans.<h4>Conclusion</h4>We propose a novel mechanism in which biliary microlithiasis induces a local inflammatory reaction at the papilla (acute papillitis) via NLRP3 inflammasome activation driven by bone marrow-derived macrophages, without causing pancreatic outflow obstruction. The gene discussed is NLRP3; the disease is acute pancreatitis.