STAT3 and Autoimmunity: Mutations in four genes, NFKB1, STAT3, CTLA4, and PIK3CD, led to not only profound B cell defects but also significant immune dysregulation, including autoimmunity, lymphoid hyperplasia, and organ infiltrative granulomatous disease, complications described in other subjects with familial inheritance (3, 16, 24, 25).