Immunologic effects of vasectomy in men and experimental animals.

Vasectomy is a widely accepted surgical procedure for male sterilization, with the unique characteristic of eliciting immune responses to self-antigens. Persistent humoral autoimmune responses to spermatozoa and transient responses to other antigens have been demonstrated in vasectomized men. Little information is available on delayed hypersensitivity reactions to spermatozoa, as well as histopathology and immunohistopathology of the testes and other organs in vasectomized individuals. Overall, the data obtained in men do not point to any immediate cause for concern and seem to justify the optimistic view that vasectomy is a safe procedure. A review of the studies performed in experimental animals similarly shows that vasectomy is followed by humoral and/or cell-mediated immune responses to spermatozoal antigens. In some species, such as rabbits and guinea pigs, it is also followed by testicular lesions, mediated by in situ immune complexes and/or delayed hypersensitivity reactions. Other sequelae may be glomerulonephritis and an increased severity of atherosclerotic lesions. Therefore, the rather encouraging picture emerging from the human studies is to a certain extent offset by the findings in experimental animals. Additional research on the effects of vasectomy is obviously necessary, as well as caution in advising this procedure to individuals who may be genetically predisposed to autoimmune disease.