IMMUNOHISTOCHEMICAL STUDIES OF THE ADULT HUMAN OVARY - POSSIBLE CONTRIBUTION OF IMMUNE AND EPITHELIAL FACTORS TO FOLLICULOGENESIS

PROBLEM: Formation of primordial follicles in adult ovaries could be a cryptic process limited to relatively small areas of the ovarian cort ex and occurring during a certain stage of the menstrual cycle. Such a n event may require a specific milieu provided by factors involved in developmental processes, i.e., morphoregulatory molecules and macropha ges. METHOD: Adult human ovaries were investigated by immunohistochemi stry for surface epithelium and granulosa cell markers (cytokeratin 18 and MHC class I), immune system-related morphoregulatory molecules (T hy-1 glycoprotein and N-CAM), and macrophage phenotypes (CD14, CD68, a nd MHC class II). RESULTS: In some ovaries 300-500 mu m areas of surfa ce epithelium were overgrown by tunica albuginea, descended into the s troma, and apparently fragmented into individual small (20-40 mu m) fo llicle-like cell nests. Differentiation of the surface epithelium was accompanied by macrophages and Thy-1 glycoprotein. Small segments of s urface epithelium showed N-CAM and a lacked MHC class I expression. In such segments, clear spherical germ-like cells migrated into the deep er stroma, associated with the microvasculature, and eventually aggreg ated with follicle-like cell nests. CONCLUSIONS: Our data suggest that surface epithelium may be involved in the formation of some primordia l follicles in adult ovaries. This process, and further follicular fat e, may require a precise interplay of immune system related morphoregu latory molecules and macrophages.