The involvement of Sertoli cells in different spermatogenic impairments has
been studied by an immunohistomorphometric technique using cytokeratin-18
(CK-18) as a marker for immature Sertoli cells, CK-18 is known to be expres
sed in Sertoli cells during prenatal and prepubertal differentiation and is
normally lost at puberty. Forty-nine azoospermic men were included in the
current study. Quantitative measurements on testicular biopsies revealed th
e highest CK-18 expression in the mixed atrophy biopsies (22 men), a lower
expression in the Sertoli cell-only (SCO) biopsies (12 men), and minimal re
sidual staining in the group considered as representing normal spermatogene
sis (six obstructive azoospermia patients). The cytokeratin immunopositive-
stained tubules were associated either with arrest in spermatogenesis or wi
th SCO, Examination of sections from nine men with microdeletions in the AZ
F region of the Y chromosome revealed that these men mere either negative f
or CK-18 expression or showed only weak residual staining. This may suggest
that the spermatogenic defect in the AZF-deteted men originates in the ger
m cell and has no impact on Sertoli cell maturation. The cause that determi
ned the spermatogenic defect in the other cases of male infertility with hi
gh CK-18 expression may have damaged both the Sertoli and the germ cells.