Pregnancy and autoimmunity: a common problem.

Successful pregnancy is considered a Th1-Th2 cooperation phenomenon (Th, T-helper), with a predominantly Th2-type lymphocytes response, together with the emerging role of interleukin (IL)-12, IL-15 and IL-18 and of other unidentified soluble factors dependent on natural killer (NK) cells. In the pathogenesis of recurrent spontaneous abortion (RSA), immunological factors have been involved such as decidual cells, complement system, cytokines and genes of the hystocompatibility complex that can determine the success or the failure of a pregnancy. A deeper insight into apparently unexplained RSA shows increasing evidences supporting both alloimmune and autoimmune mechanisms, with autoantibodies playing a major role. The best-characterised pathogenic autoantibodies are anti-phospholipid antibodies, and also other autoantibodies, such as anti-Ro/SSA and anti-La/SSB, have been found to be associated with an increased rate of abortion, poor pregnancy outcome and several other obstetric manifestations. This intriguing mixture has been unveiled only in the last few years with the discovery of novel pathogenic mechanisms that can be targeted in the prevention and treatment of obstetrical complications occurring in the course of an autoimmune disease.