Immunology of Recurrent Pregnancy Loss Update

A significant number of women with recurrent pregnancy loss (RPL) have various auto- and cellular-immune abnormalities, suggesting underlying immunopathology. However, immune abnormalities are often disputed, and clinical translation has been slow. This review discusses the recent findings and advances in the RPL of immune etiologies and reassesses the current application of immune findings for RPL.

Women with RPL have a significantly higher prevalence of autoantibodies such as antiphospholipid, antinuclear, and antithyroid antibodies, and peripheral blood NK cell levels, NK cytotoxicity, Th1/Th2, and Th17/Treg ratios than those of controls. Recent technological advances revealed that multiple interactions among the immune effectors in peripheral blood and decidual tissues affect the immune balance via various mechanisms, causing the RPL. Therefore, detecting auto- and cellular-immune abnormalities, including increased NK cell levels, cytotoxicities, and shifted Th1/Th2 and Th17/Treg ratios, may significantly improve the reproductive outcomes of women with RPL.

Proper diagnosis is the cornerstone of the primary approach in clinical practice. Autoimmune and cellular immune abnormalities are common in women with RPL. Proper screening for autoimmune and cellular abnormalities should be considered for women with RPL. Women with RPL of immune etiologies should be properly treated using immunotherapy.