A decreased number of CD4+ CD25+ Tregs has been observed in recurrent spontaneous abortion (RSA) cases (Yang et al., 2008) which can be associated with FOXP3 (OMIM: 300292) downregulation as an essential regulator of CD4+ CD25+ Tregs development and function through NFAT (Mei, Tan, Chen, Chen, & Zhang, 2010; Wu et al., 2006). Here, CD4 is linked to spontaneous abortion.