小于胎龄儿（SGA）因其发病率的上升及远期结局差，已成为儿科学及围生医学不容忽视又迫切需要解决的问题。小于胎龄儿的发病原因至今未明，亦缺乏有效的救治措施。母-胎界面的免疫微环境是维持正常妊娠的重要因素，免疫微环境的异常变化可导致妊娠相关的多种疾病包括胎儿生长受限（FGR）及SGA的发生。本研究拟在课题组前期项目的工作基础上，首先通过免疫组化及流式细胞检测技术，对SGA母胎界面的主要免疫细胞群NK细胞及γδ T细胞的数量、分布、表型，以及它们的相关细胞因子分泌及细胞毒功能变化特征进行研究；再通过体外直接与间接的细胞共培养技术，进一步研究NK与γδ T细胞对滋养细胞功能的影响及相互调节的分子机制，从而证实免疫微环境变化对胎盘功能及胎儿生长发育的重要性。这些研究成果将有助于我们对SGA母胎界面的免疫微环境特征获得较全面的认识，也必将对临床探索更有效的预防和纠正SGA的诊治方法带来新的思路。

The small for gestational age (SGA) have attracted much more attention of pediatrics and perinatology because of the rising incidence of a disease and poor long-term outcome. The etiology of SGA has not yet fully understood, which lacking effective treatment as well. The immune microenvironment of maternal-fetal interface is an important factor that maintaining normal pregnancy, and anomalous change of immune microenvironment may lead to many diseases associated with pregnancy including fetal growth restriction (FGR) and SGA. On the basis of our previous work, we will first focus on the quantity, phenotype, cytokine secretion and cytotoxicity of NK and γδ T cells, the main population of immune cells on maternal-fetal interface of SGA by immunohistochemistry and flow cytometry; Further, the effect of function of Sertoli cell by NK and γδ T cells and mutual adjustment mechanism will be studied by direct and indirect culture system in vitro, which confirming the importance of immune microenvironment changes on placenta and fetal growth and development. Our research achievements will help us obtaining more comprehensive understanding of immune microenvironment of SGA maternal-fetal interface, and also suggesting a new strategy to explore more effective prevention and correction of SGA.