Figure 1.

B cell behavior during pregnancy. Pregnancy factors promote the generation of asymmetric antibodies that protect placental antigens from immune reactions. In pre-eclampsia, B-1a B cells can turn autoreactive and secrete antibodies against the angiotensin receptor 1. In patients with autoimmune disorders, it is possible that B cells secrete more autoantibodies and endanger the gestation. A newly described B cell type, the so-called regulatory B cells, produces IL-10 and is proposed to positively influence pregnancy by hindering Th1 immune responses.