Autoimmune polyglandular disease is associated with antibodies to testis.

Antibodies reacting with the enzymes cytochrome P450c17 and P450scc are referred to as steroid cell antibodies and are found in Leydig cells between the seminiferous tubules. Cyotchrome P450 is involved in the biosynthesis of steroids and are associated with autoimmune polyendocrinopathies.

Image: Primate testis stained with IgG from patient. Note, cell cytoplasm of the Leydig cells shown in green while the nuclei are counter stained red with ethidium bromide. NB. This antibody cross-reacts with ovary as they possess common antigens.