IL10 and infection: Indeed, while aTregs (Foxp3− Tregs) are known to be the major producers of IL-10 in filarial infections 21 and visceral leishmaniasis 22, Th1 cells are an important source of IL-10 in others, including malarial, infections 23, and in animal models of toxoplasmosis 24 and cutaneous leishmaniasis 25.