Research advances in role of immune susceptibility in unexplained recurrent spontaneous abortion

The incidence of unexplained recurrent spontaneous abortion (URSA) is 1%-5%,which is a kind of early abortion of recurrent spontaneous abortion (within 12 weeks of pregnancy).Previous studies have shown that maternal and fetal interface immune tolerance imbalance is an important mechanism of URSA occurrence,and immunological factors abnormality is the main cause of URSA occurrence.Therefore,this article comprehensively reviews the research advances in the pathogenesis of URSA from the key factors in the innate and acquired immune systems related to maternal and fetal immune tolerance imbalance,such as natural killer cells,macrophages,dendritic cells,blocking factors,Th1/Th2,Th17/Treg and their cytokines as well as complement,so as to provide scientific evidences for the study on the pathogenesis of URSA and its clinical diagnosis and treatment.