New software programs have been developed that are driving chains of donors, to create something like a marketplace for organs – but one where supply and demand are balanced not through pricing but through altruism. The New York Times reports that ‘the genius of the computer algorithms driving the kidney chains is that they find the best medical matches – thus increasing the odds of a successful transplant – by decoupling donors from their intended recipients, allowing for a kind of US barter market for kidneys.
Despite the crushing demand, the sale of kidneys is banned in every country in the world except Iran. But reports the newspaper, in the US, more than 100,000 people with renal failure are on the list for a deceased-donor kidney, typically waiting between four and five years. Last year, 4,270 people died waiting.
Few but free-market absolutists would argue for repealing the 1984 law banning the organ trade in the US, but most would agree something should be done to increase the supply of kidneys for transplant. And, the report says kidney patient Mark Kim would have continued to wait on the national list, despite having several willing donors, were it not for a company called BiologicTx.
Thanks to its software, Kim was able swap his sister’s kidney for a Marine’s kidney. The Marine, a woman named Liz Torres, gave up her kidney to ensure that her mother got a kidney, which came from a young social worker, Ana Tafolla Rios, who was a better match. Rios passed hers along to secure one for her ailing mother from Keith Rodriguez, a young man from Fresno. He let go of his to procure one for his mom, Norma, a 52-year-old dental assistant with polycystic kidney disease. All these people underwent surgery over two days in March at the California Pacific Medical Centre in San Francisco, in what is called a kidney-transplant chain.
The software programs driving such chains create something like a marketplace for organs – but one where supply and demand are balanced not through pricing but through altruism. The report says the genius of the computer algorithms driving the kidney chains is that they find the best medical matches – thus increasing the odds of a successful transplant – by decoupling donors from their intended recipients. In the US, half a dozen of these software programs allow for a kind of barter market for kidneys.
Garet Hil, the founder and CEO of the National Kidney Registry, the largest kidney-chain exchange program in the world, has a background in financial services, not medicine. He borrowed concepts from the brokerage industry when developing the registry’s algorithm.
Each chain starts with a completely altruistic donor, someone who expects nothing in return. Economists call an arrangement like this a matching market. “It is not fundamental to economic theory to assume people are selfish,” Alvin E. Roth, an economist who teaches at Stanford University, says. Roth won the Nobel Prize in economics in 2012 for his work using game theory to design matching markets, which pair unmatched things in mutually beneficial ways. In such markets, money does not decide who gets what. Instead, these transactions are more akin to elaborate courtships.
In the case of kidney exchange, this matchmaking happens at a microcellular level. White blood cells contain genetic markers, proteins that help our immune systems distinguish between our bodies and foreign invaders. The more closely a transplant recipient’s genetic markers match a donor’s, the more likely the body is to adopt that foreign kidney as its own rather than attacking it.
All these genetic variables mean that linking unrelated donors and recipients requires the kind of computational heft humans can’t manage with pen and paper.
Last year in the US, 544 kidneys were transplanted through these paired exchange programs, and many other countries are beginning to adopt them. Surgeons in Poland, Italy and Argentina completed their first chains last year. As more donor-and-recipient pairs enroll, the chains can accommodate increasingly complicated transactions.Full report in The New York Times