IL1B and cryopyrin-associated periodic syndrome: In line with this, patients with recurrent fever syndromes associated with increased IL-1β levels such as familial cold auto-inflammatory syndrome, the mildest form of CAPS, and Periodic Fever, Aphthous stomatitis, Pharyngitis and Adenitis (PFAPA) syndrome often have a lower frequency of upper respiratory infections (H. Hoffman, personal communication).