Based on this ground, the aim of our study was to compare the immunomodulatory effects of pregnancy on five leukocyte populations (i.e., CD4+ and CD8+ T cells, CD4+CD127−CD25high T cells [Treg], CD56brightCD16− NK cells [NKbright], and CD14+CD163+ monocytes [M2]) in peripheral blood of MS patients and healthy women at different times during gestation. Here, CD4 is linked to myeloid sarcoma.