ABSTRACT
The involvement of abnormal Sertoli cell differentiation in different spermatogenic impairments has been studied by an immunohistochemical technique using cytokeratin-18 [CK-18] and anti-vimentin antibody. CK-18 is used as a marker for immature Sertoli cells as it is expressed only in Sertoli cells during prenatal and pre-pubertal differentiation and is normally lost at puberty. Forty two azoospermic men were included in the current study. These included 9 cases with obstructive azoospermia, 8 cases with pure [congenital] type of Sertoli cell only syndrome [SCOS], 12 with secondary type syndrome [SCOS], and 13 with spermatogenic maturation arrest. Vimentin was ubiquitous immunohistochemical marker associated with both normal and impaired spermatogenesis. CK-18 expression was associated with various stages of spermatogenic arrest an[l secondary type of Sertoli cell only syndrome [SCOS]. The expression of CK-18 may be a manifestation of de-differentiation of Sertoli cells or persistence of immature cells. Moreover, useful criteria to predict the absence of spermatozoa in cases of pure Sertoli-cell only syndrome can be obtained by a definite recognition of the typical histological patterns and refined by CK-18 immunostaining aid, especially in difficult cases