To address this matter, we compared the immunomodulatory effects of pregnancy on five leukocyte populations (i.e., CD4+ and CD8+ T cells, CD4+CD127−CD25high regulatory T cells, CD56brightCD16− NK cells, and CD14+CD163+ monocytes) in peripheral blood from different cohorts of MS patients and healthy women at different times of gestation, as well as in decidual samples from the placenta of MS patients and healthy women collected after delivery. The gene discussed is CD163; the disease is myeloid sarcoma.