The critical role of Th2 cells for the protection of host tissue from cytotoxic effects and correct granuloma formation is further substantiated by studies showing that injection of the Th1 cytokine IFNγ interferes with granuloma formation and IL-12- deficiency–in fact Th1-ablation–increases granuloma size and Th2-mediated inflammation (117, 118). This evidence concerns the gene IFNG and Granuloma.