CD4 and type 1 diabetes mellitus: (2) studied changes in the microbiota of children with T1D and healthy children (control group) and found that the fecal bacterial content was significantly lower in the T1D group than in the control group; it was also found that Clostridial microbiota IV and XIVa also play an important role in the homeostasis of the immune fecal environment and that their products, short-chain fatty acids, regulate the expression of Foxp3 in CD4+ T cells (3).