Furthermore, CMC is not present in 100% of the patients and the match between CMC status and the presence of anti-IL-17F and/or IL-22 autoAbs is not absolute but correlative. Notably, ~ 100% of APS1 patients have high titer IgG autoantibodies (autoAbs) that neutralize type I interferons, especially IFN HT ht and IFN HT ht subtypes [[1]]. S1 was originally tested for autoAbs and I AIRE i mutations at age 7 months [[2]] because one of his siblings had presented with severe APS1 manifestations, starting with CMC from late infancy. In striking contrast, by age 7 months, S1 already had persistently high titer autoAbs against IFN HT ht and IFN HT ht and lower (but increasing) titers against IL-17F, though not against IL-17A (Fig. [Extracted from the article]