Immune complex orchitis in infertile men. Immunoelectron microscopy of abnormal basement membrane structures

Testicular biopsies from 30 patients with fertility disorders were investigated by peroxidase-labeled antibodies against IgG and C3 at an ultrastructural level. Three types of abnormal basement membrane structures (ABMS) proved to be positive. Immune-type deposits (ABMS type 2), ABMS with vesicular particles (ABMS type 4), and those with membranous structures (ABMS type 5) stained positively for IgG and C3. In 21 cases ABMS were positive for at least one of the antisera. Two additional cases showed a linear reaction for IgG and C3 in the basement membrane. According to the number and size of positive ABMS, the cases were divided into three groups. Group I contained 10 cases with extensive ABMS types 2, 4, and 5 positive for IgG and C3 and two cases with linear positivity. At light microscopy, the changes varied from light to severe tubular atrophy. In these latter cases ABMS types 4 and 5 predominated, whereas in the light and focal tubular lesions ABMS type 2 did. In group II, eight cases revealed few and small ABMS positive by immunoelectron microscopy and no more than slight tubular changes at light microscopy. In group III, minimal or no ABMS were present, but in three cases mast cells were numerous in the interstitial tissue. The demonstration of immune deposits in the basement membrane of seminiferous tubules is interpreted to be the result of an antibody-mediated damage to the germinal epithelium leading to tubular atrophy. In one case obstruction of the sperm ducts and in another torsion of the testis are incriminated as events triggering the autoimmune process. Linear staining of the basement membrane for IgG and C3 in two cases suggests the development of antibasement membrane orchitis.