IL1B and PFAPA syndrome: In conclusion, even though the exact pathogenic mechanism underlying PFAPA still remains unknown, the clinical overlapping with monogenic HPF, the high rate of positive familial history in patients, the clearly central role of proinflammatory cytokines, mainly IL-1 among them, and the variable association with some hypomorphic mutations of genes involved in HPF all point in our opinion to the idea that PFAPA syndrome should be considered a polygenic autoinflammatory disease [26–28].