A histologic study of the auto-allergic testis lesion in the guinea pig.

The auto-allergic lesion in guinea pigs inoculated with homologous testis plus the Freund adjuvant was investigated histologically. The lesion was found to consist of disseminated foci of perivenous inflammation, lymphocytes and histiocytes predominating in the cellular infiltrate, with invasion of epididymal, rete, and seminiferous tubules and destruction of tubular contents. Guinea pigs up to 800 gm. showed a rapidly progressing diffuse hypo- or aspermatogenesis, which appeared to be secondary to the inflammatory disease. In these animals, the process resolved leaving an atrophic testis with few or no indications of the preceding inflammation and fibrotic scarring only in the rare instances in which actual necrosis of connective tissue elements had occurred. In 1200 gm. animals there was no general hypospermatogenesis and the late findings were limited to foci of aspermatogenesis. This disease then is an experimental auto-allergic orchitis followed by testicular atrophy without scarring. Its morphologic similarity to mumps orchitis and to sterility with "germinal cell aplasia" in man is commented on.