AIM2 and PFAPA syndrome: Although the pathogenesis of PFAPA remains poorly understood, it is assumed that an environmental trigger in the context of immune abnormalities of the host may trigger disease episodes through activation of innate immune system, possibly via “absent in melanoma 2” (AIM2) inflammasome in monocytes, which leads to activation and secretion of IL-1β, induction of Th1-chemokines, and subsequent migration of T-lymphocytes into periphery [5].