Evaluating T and B cell lineage differentiation stage and related prognostic impact in miscarriage

The WHO (World Health Organization) defines miscarriage as two or more pregnancies documented in woman medical history ended up with spontaneous miscarriage at stage of up to 22 weeks of pregnancy from conception. Habitual miscarriage of pregnancy (HMP) is one of high priority problems for infertile marriages comprising 5-20% among other causes of miscarriage. As many as 80% of all idiopathic HMP cases are associated with immune-related disorders. Currently, many researchers have being paying more attention to examining effects of T and B cells at varying differentiation stage in developing immune response against allogenic graft and formation immunological tolerance. However, it is worth noting that pregnancy-associated human hormone chorionic gonadotropin (HCG) exhibits a marked immunosuppressive effect by regulating regulatory T (Treg) cell functional activity. It has been proven that HCG contributes to increasing Tregs level in periphery and recruiting them to the embryo implantation zone, thus establishing immunological tolerance during pregnancy. However, no data regarding HCG effects on T and B cells at various differentiation stage were obtained during HMP. A correlation analysis between frequency of T and B cells at various differentiation stage and level of serum HCG in women with HMP was performed. It was found that low level HCG was associated with decreased naive T and B cell frequency paralleled with elevated percentage of effector memory CD8⁺ (Tem) that may serve as a poor prognostic sign especially in early stage of pregnancy.