STAT1 and Autoimmunity: Because of the similarities in clinical presentation of CMC and autoimmunity and decreased peripheral blood Th17 frequencies between patients with APECED and STAT1 GOF mutations, our study examined STAT1 protein and phosphorylation levels in patients with APECED and shows that APECED patient monocytes do not share the same cell-intrinsic increase in STAT1 protein and phosphorylation levels as cells from patients with STAT1 GOF mutations.