Absence of anti-Müllerian hormone (AMH) and M2A immunoreactivities in Sertoli cell-only syndrome and maturation arrest with and without AZF microdeletions.

BACKGROUND Some genes identified in the AZF locus are expressed only in germinal cells; others are ubiquitous. AZF microdeletions seem to occur at the earliest stages of ontogenetic development, and one might therefore assume that Sertoli cells preserve some immature characteristics and that their immunophenotype may be modified by the existence of a molecular defect. MATERIALS AND METHODS Two immunohistological markers of Sertoli cell immaturity [anti-Müllerian hormone (AMH) and M2A] were tested in two histopathological groups (maturation arrest at spermatocyte I stage and Sertoli cell-only syndrome). We analysed 68 testicular samples obtained from 39 patients with non-obstructive azoospermia associated or not with AZF microdeletions. RESULTS The absence of M2A and AMH immunoreactivity in adult gonads was observed without any correlation to spermatogenetic impairment or molecular deficit in the AZF region. In the samples of these two series, Sertoli cells showed a mature phenotype for AMH and M2A markers. CONCLUSIONS In patients with AZF microdeletions, the genotype-phenotype correlations seem to be more complex than has been suggested previously; more detailed characterization of the immunohistochemical phenotype associated with the molecular defect may be useful in understanding the spermatogenic failure mechanism.