TCF4 and digestive system disorder: For three PPI modules (out of 119 modules) we detected an overrepresentation of the Ai6, Ai21, and/or digestive system disorder categories (Fig. 6a, b), further supporting the hypothesis that the iTreg subnetwork contains genes that act in the same autoimmune disease neighborhood, such as LEF1, BACH2, TCF4, KIF1B, CXCR5, and NOTCH1, which have been implicated in autoimmune diseases by independent reports.