IgG anti-(Fab�)2 Antibodies in Early Pregnancy Sera of Women with Anti-thyroid Antibodies and Normal Outcome or Spontaneous Abortions

Abstract

Anti-thyroid antibodies (atbs) (anti-TPO, anti-TG, anti-TRH receptor) are autoatbs that recognize specific antigens that belong to thyroid structures. Several mechanisms were proposed to explain the breaking of immunotolerance to thyroid antigens. Our previous studies showed that IgG-anti-F(ab�)2 atbs exert immunosuppresives effect in vitro and inverse correlate with autoatbs in certain autoimmune diseases. Relying on sera from pregnant women with and without anti-thyroid atbs, respectively with or without spontaneous pregnancy loss we intended to analyze the IgG-anti-F(ab)2 atbs titers in sera of these categories of patients. The lot of patients consists of 126 pregnant women out of which 47 had a normal course of pregnancy and 79 experienced spontaneous abortion. Anti-TPO, anti-TG, and IgG-anti-F(ab�)2 atbs titers were measured in sera of these women. Although a difference was found between IgG-anti-F(ab�)2 atbs titer in pregnant women with positive versus negative anti-thyroid atbs, this was not statistically significant. IgG-anti-F(ab)2 atbs titer is higher in women with a normal course of pregnancy compared to women spontaneous pregnancy loss. Differently from other autoimmune diseases, our data show that IgG-anti-F(ab�)2 atbs are not inversely correlated to anti-thyroid atbs titers. Higher IgG-anti-(Fab�)2 atbs titers were found in pregnant women with normal course of pregnancy compared with those with pregnancy loss.