Familial Mediterranean fever and related periodic fever syndromes/autoinflammatory diseases

PURPOSE OF REVIEW: The spectrum of periodic fever syndromes (PFS)/autoinflammation diseases is continuously expanding. This review provides an overview of the primary research and an update on the main clinical developments in these disorders published in the past 12-18 months. RECENT FINDINGS: IL-1β is pivotal to the pathogenesis of most of the PFS. In familial Mediterranean fever (FMF) MEFV mutations lead to gain of pyrin function, resulting in inappropriate IL-1β release that is dependent on ASC but not the NLRP3 inflammasome. Anti-IL-1 therapy is effective in tumour necrosis factor receptor-associated periodic syndrome (TRAPS), whilst both spontaneous and pathogen-associated molecular patterns (PAMPs) induced IL-1β release have been demonstrated in NLRP12-associated periodic syndrome (NAPS12). Somatic NLRP3/CIAS1 mosaicism is a significant cause of cryopyrin-associated periodic syndromes (CAPS). Close connections have also been established between metabolic and inflammatory pathways. In TRAPS increased reactive oxygen species (ROS) of mitochondrial origin leads to production of pro-inflammatory cytokines, whilst NLRP3 inflammasome activation in type 2 diabetes (T2D) is induced by oligomers of islet amyloid polypeptides (IAPP). SUMMARY: Caspase 1 activation and IL-1β release is central to the pathogenesis of many autoinflammatory syndromes. This is supported by the effectiveness of anti-IL-1 biologics in treatment of these disorders.