Medications still necessary nine years after kidney transplant

I had a kidney transplant nine years ago. Other than a bout with COVID that landed me in the hospital a couple of months ago, I have been rather healthy and lead a normal life. I take a handful of pills each day that are mainly aimed at suppressing my immune system so I do not reject my new kidney.

My question is, after nine years, wouldn't my body have accepted this new organ as its own and the immunosuppressant drugs would no longer be necessary?

— G.K.

I am glad to hear you are doing so well. A kidney transplant leads to a longer and better quality of life than dialysis does for most recipients.

Besides being a precious gift, a kidney has an enormous source of foreign proteins that your body desperately wants to get rid of. The system is complex, but your body doesn't recognize your transplanted kidney as a part of you due to the presence of specific and major histocompatibility antigens that aren't yours.

Your immune system sees this kidney like an invader — such as an infection or a cancer — that it needs to get rid of. The handful of pills you take is precisely dosed to keep your immune system from destroying your transplanted kidney, but not so suppressed that it can't respond to real infections and cancers.

Over time, you may need slightly less immunosuppressive medication, but your body will never stop seeing the transplanted organ as anything other than foreign. There may be an exception in infants whose immune systems aren't fully developed and won't recognize the organ as an invader. This has been reported with heart transplantation in infants, but not in adults with fully formed immune and inflammatory systems.

So, don't stop your medication. Your body will quickly reject the organ, and you will require powerful medication to try to stop the rejection. This then makes you susceptible enough to bacterial and viral infections that will mandate antibiotics and antivirals, in addition to the medications to stop your body from rejecting the kidney.

I read that nicotine is antiparasitic. I suspect that a nicotine patch may keep bird mites from biting patients. Do you have any information on this? We currently have an invasion in a patient.

— Professor D.F.

Nicotine is known to have antiparasitic properties, but I couldn't find any data to support the use of a nicotine patch to prevent bird mites from biting a human.

Bird mites, which are tiny and associated with many bird species (especially pigeons), can bite humans, but cannot complete their life cycle on humans. So, getting rid of the birds and their nests is usually adequate enough to stop the problem. A pest-control professional should be able to treat the home.

Bird mite bites look very much like bedbug bites. In the short-term, DEET is effective to ward off mites and keep them from biting people. I did read a case report of gerbils being an unexpected host of bird mites, so you might want to ask about that.