Prior investigations [31, 33] did not make comparative measurements of IL-17 production by decidual CD4+ T cells in normal pregnancy and miscarriages and none identified Th17 subpopulations able to produce IL-4 or IFN-γ together with IL-17 (Th17/Th2 and Th17/Th1, respectively). This evidence concerns the gene IL4 and spontaneous abortion.