The lessons of vasectomy-a review.

Vasectomy has become the most common method of permanent male sterilization for birth control. It is a simple operation that requires approximately 20 minutes to perform. Under local anaesthesia the vas deferens is cut and ligated. The patient is considered sterile when the ejaculate is sperm-free. Since spermatogenesis is not arrested by the operation and since the normal route of sperm removal is blocked, other mechanisms of sperm removal are developed. These mechanisms include sperm resorption into the interstitial tissue, granuloma formation, phagocytosis and immune response to sperm antigens. More than half of the men subjected to vasectomy develop demonstrable antibodies to one or more sperm antigens. Having been induced by the individual's own untreated antigen without the aid of external adjuvants, the response justifies the most rigorous definition of autoimmunity. The wide scale use of vasectomy, therefore, provides the clinical immunologist with a unique opportunity to study a longstanding, induced autoimmune response in otherwise normal human subjects. It is a matter of special importance to study these subjects carefully, in order to learn the maximum about human autoimmunity.