Part of CD68+ macrophages in the clearence of apoptotic bodies in human metanephros.

According to recent research on mice, less on human material, cells responsible for clearing apoptotic cells away during development are, besides non-professional phagocytes, also tissue-fixed macrophages. The aim of our work was the determination of macrophage role in the phagocytosis of apoptotic bodies in neogenous zone of human metanephros. Histologicaly normal kidneys were collected from embryos and fetuses ranging from the 8th-28th week of IUD. These tissues were routinely processed. In the first step we detected CD68+ cells by means of standard indirect three-step immunohistochemical method having used MAb NCL-CD68-KP1 (macrophage marker) to find out whether such cells are actually present. In the second step tissue sections were labelled by double-staining principle (TUNEL technique for the detection of apoptosis and above mentioned macrophage marker) to judge co-localization of these two items. The slides were observed by using immersion objective and the amount of apoptotic cells was expressed in percents. CD68+ macrophages appeared dispersely as single cells or small groups in all the ages studied. According to our results, CD68+ macrophages phagocytose 37-75% of apoptotic cells present in neogenous zone and the number of engulfed apoptotic cells increases in the 12th week of the IUD, i.e. in the early fetal period and later it merely fluctuates.