The role of NK cells in the autoimmune thyroid disease-associated pregnancy loss.

Pregnancy loss is a frequent event. Autoimmune thyroid disorders and altered natural killer (NK) cell functions are two distinct risk factors, which independently could induce adverse pregnancy outcome. Thyroid autoimmunity has been an object of increased attention by investigators in the context of pregnancy loss. Peripheral NK cells and uNK cells comprise distinct cell populations in terms of phenotype and function but they play an important role in the course of a normal human pregnancy via several potential functions. In autoimmune thyroid diseases, several abnormalities of killer cell activity have been described. The functional defects involving NK maturation and/or functional activation observed in Graves' disease patients could independently influence the reproductive outcome. This suggestion needs extensive investigation and could be important for the therapeutical approach in preventing pregnancy loss in patients with thyroid autoimmunity.