［Key words］ lymph nodes； mesentery； persons； fetus； lymphocyte； apoptosis
To study the apoptosis of lymphocytes in mesenteric lymph nodes （MLNs）during different stages of human fetus development. Methods： Thirty-five human fetuses were collected. The Hermatoxylin-Eosin（HE） staining， immunohistochemistry apoptosis method (in-situ dT, dT-mediated dUTP nick labeling，TUNEL), and cytometry were used in this study. Results： At the 9th week of fetal age, no apoptosis lymphocyte was seen in the primordium of the MLNs. In 11~12 weeks of fetal development, a few of apoptosis lymphocytes could be found. Obvious apoptosis lymphocytes were observed from the 13rd week to the 32nd week. They occurred singly and were phagocytized by macrophage. But there was not distinct difference between each stage of the developing fetuses (P>0.05)．Conclusions： (1) The apoptosis of lymphocytes is a common phenomenon during MLNs growth in human embryo development; (2)During the development of human fetus, the MLNs have screening function to lymphocytes through apoptosis.
