IL17F and autoimmune polyendocrine syndrome type 1: In 2010, two independent studies reported that almost all APS-1 patients, of all ages, tested, had high serum titers of IgG auto-Abs against at least one of the Th17 cytokines (IL-17A, IL-17F, and/or IL-22; Liang et al., 2006; Zheng et al., 2007), neutralizing up to 50 ng/ml IL-17A, 10 ng/ml IL-17F, and/or 0.5 ng/ml IL-22 (in plasma diluted 1/10; Kisand et al., 2010; Puel et al., 2010a).