Autoinflammatory diseases are characterized by apparently unprovoked generalized inflammation in the absence of infection or high titre autoantibodies [39]. The better defined diseases within this group are monogenic disorders, especially the hereditary periodic fever syndromes. These genetic diseases have provided insight in innate immune mechanisms and in the pathogenesis of autoinflammatory diseases in general. The common pathophysiologic feature for many of these disorders appears to be excessive interleukin- (IL-)1 signaling