IL1A and fibrodysplasia ossificans progressiva: Using principal component analysis, Barruet and colleagues reported no significant differences in IL-1α and IL-1β levels, secreted by lipopolysaccharide (LPS)-stimulated monocytes of either control or FOP patients (during a flare), and significantly increased IL-1 receptor antagonist levels in FOP monocytes, after LPS stimulation [14].