Can You Be Allergic to Your Sperm?
They sat in front of me, notes in hand, having read all they could, and looking somewhat concerned. “We read that vasectomy reversals don’t work because of antibodies that men make to their sperm. Is this true?”
Don the Immunology Hat
Practically speaking, the world’s first immunologist was the formidable warlord King Mithridates VI of ancient Greece, who ruled in the first century B.C. His father, a prince, died by being poisoned in his own house. A young Mithridates vowed that the same would never happen to him. So, he imbibed small amounts of various poisons during his life so that he could never be poisoned. It worked. In fact, so well that he couldn’t even poison himself when he wanted to. The first densensitization therapy.
The Ultimate Allergy
In truth, all men are “allergic” to their sperm. They just don’t know it. And it all starts right after birth. Within 6 months and certainly after breastfeeding ends, a baby’s immune system is all set up and ready to go. It learns how to react to every little thing that is touched, inhaled or ingested and can quickly figure out what is “self” (let it go) or “non-self” (react, react!). All very important for critters that touch all they see and put everything imaginable in their mouths.
But the one thing that their cute, little, developing immune systems don’t see is sperm, because sperm arrive on the scene at puberty, well after the immune system is all sorted out. So, sperm are genuinely “foreign” to the body. Indeed, they are deemed “non-self” by the body’s defense system. That’s why they are all walled off down there within the family jewels, held away from body and kept at a lower temperature. This keeps them off the immune system’s radar and out of harm’s way. Until something disturbs this balance, and sperm are “seen.” Then all hell breaks loose.
In fact, it’s the vasectomy and not its reversal that’s kicks things off. Antibodies develop to sperm after “inoculation” by the vasectomy, similar to what occurs with a typical vaccination. Like many vaccines, this usually causes no symptoms, and the immune system calms down as things heal up. But, alas, the immune system has an exquisite memory, and the next time it sees sperm, at the time of vasectomy reversal, it acts up again and generates antisperm antibodies. This likely occurs in every man at reversal and may be the reason for low sperm motility on semen analyses early on after the procedure. But, again, as things seal up and the exposure is contained, antibodies wear off and things settle down.
So my answer to this couple’s concern is that antibodies after reversal are expected in everyone and only rarely cause absolute infertility. They can, however, increase the time it takes to get pregnant after the procedure, even with an otherwise “normal” semen analysis. I also don’t hesitate to remind them that good things come to those who wait.