Very recently, we observed a prevalence of Th17/Th2 cells (producing IL-17 and IL-4) in the decidua of those experiencing successful pregnancy, whereas the presence of Th17 (producing IL-17 only) and Th17/Th1 (producing IL-17 and IFN-γ) cells was exclusively found in the decidua of those experiencing unexplained recurrent abortion [25]. The gene discussed is IL4; the disease is abortion.