Comparing the Frequency of CD4+T Cells in Recurrent Spontaneous Abortion Women with and without Anti-thyroid Peroxidase (TPO).

Thyroid autoimmunity, being recognized by the presence of auto-antibodies against thyroid peroxidase (TPO) and thyroglobulin, has known to be associated with increased risk of recurrent spontaneous abortion (RSA), even in euthyroid subjects. There was no robust evidence regarding T cell deviations in anti-TPO positive RSA patients. The aim of this study was to investigate if the numbers of different CD4+T  subsets were different in women who experienced RSA and have an anti-TPO antibody from those without autoantibody and normal fertile women or not. In this study, peripheral blood samples were obtained from three groups of women (age: 20-35 years) including RSA anti-TPO positive (n=17), RSA anti-TPO negative (n=27), and fertile (n=29) groups. The frequency of T helper (Th) 1, Th2, Th17, and regulatory T cells (Tregs) and also, the proportions of Th1/Th2 and Th17/Treg were measured by flow cytometry and compared between groups in different menstrual phases. The findings indicated elevated levels of Th1 in anti-TPO+ RSA in comparison with those without anti-TPO (p-value: 0.004), exclusively in the luteal phase. Other T cell subsets were different only between RSA and control groups. Also, the Th1/Th2 and Th17/Treg ratios were increased in both RSA groups compared to fertile women. The only subset of CD4+ T cell different between RSA groups (i.e. with and without anti-TPO) was Th1 cells. Other CD4+ T cells' deviations including Th2, Th17, and Treg cells could be related to the presence of abortion, regardless of the underlying thyroid autoimmunity state.