Hormones, immune response, and pregnancy in healthy women and SLE patients

During pregnancy the maternal immune system is modified in order to achieve immune tolerance toward paternal antigen expressed on foetal cells. These modifications, which occur both at the foeto-maternal interface and in the systemic circulation, are driven by oestrogens and progesterone whose blood concentrations increase during pregnancy. The cytokine profile is also modified. Th2 cytokines are enhanced while the Th1 response is inhibited. This could explain why Th1-mediated autoimmune diseases tend to improve and Th2-mediated diseases, such as systemic lupus erythematosus (SLE), tend to worsen during pregnancy. However, whether or not SLE relapses more frequently during pregnancy is still a matter of debate. Steroid hormone and cytokine profiles differ in SLE patients compared with healthy subjects during pregnancy leading to a dysregulation of the balance between cell-mediated and humoral immune response, which, in turn, could explain the variability of the SLE course during gestation. This review focuses on hormonal-related cytokine changes observed during pregnancy in healthy subjects and SLE patients.