Our recent article about age limits for Be The Match Registry prompted a lot of responses from registry members. Many of them were unhappy, in some instances, really unhappy, about the upper age limit. Be The Match Registry only accepts donors between the ages of 18 and 60. Registry members are automatically moved to inactive status on their 61st birthday. We’re happy that the post generated so much thoughtful and vigorous discussion. It shows the passion and commitment of donors toward helping patients. I will try to address some of the issues.
Transplant doctors prefer younger donors for their patients
In our previous post, we stated that one reason for the upper age limit is to provide the best treatment for patients. Doctors weigh many factors when selecting a donor for one of their patients; the age of the potential donors is one of them. Transplant doctors want younger donors. Some of this is data-driven; there are publications suggesting that patients with younger donors do better. See for example, http://bloodjournal.hematologylibrary.org/content/98/7/2043. Some of it is judgment. It is very clear that the bone marrow ages just like other organs; the cellularity of bone marrow declines with age. You can’t get as many cells out of an older donor as you can from a younger one, and higher cell dose improves the chances of success.
Additionally, there are little parts of each cell’s chromosomes, called telomeres, whose length reflects the residual ability of the cell to divide. Guess what? — the telomeres of bone marrow cells get shorter with aging. If you do bone marrow transplants serially in mice, the bone marrow poops out when the telomeres are gone. Can bone marrow from a 65-year-old donor last another 45 years or more in a 20-year-old recipient? We don’t know, but a lot of doctors are reluctant to do the experiment. Most would like to put young bone marrow in young patients, and older patients, too, for that matter. Finally, it is also true that diseases of the bone marrow, like myeloproliferative syndrome, myelosdysplastic disease and acute leukemia, are diseases of aging; their frequency begins to increase around age 45 and continues relentlessly throughout older age.
World Marrow Donor Association standards
The NMDP is one of 67 donor registries around the world that participate in the World Marrow Donor Association (WMDA, www.worldmarrow.org), an organization that facilitates international donation and transplantation, and promotes the interests of donors. WMDA standards require donor registries to stipulate an upper age limit not to exceed 60 years. In fact, many other donor registries have set lower age limits for joining: age 55 in Germany, 50 in Canada, 40 in Australia and in the United Kingdom, 54 in Japan. Most of these registries consider members already on the file eligible to donate up to age 60. Maybe the NMDP could work around this standard if there was a compelling reason to do so, but the simple fact is — no registry in the world keeps donors past the age of 60.
Age is a factor in a person’s health
We know there are many people over age 60 who are in excellent health. There are also many who are not. I talked about aging bone marrow above, but other health problems also increase with age. The rate at which potential donors are found medically unable to donate is highest in NMDP’s older donors. This higher rate of medical deferral matters because it presents a risk to patients. When the selected donor turns out to be unable to donate, transplant may be delayed, which can jeopardize a patient’s likelihood of success. Medical deferral often happens late in the process, when the donor is being “worked-up” for donation, and it is a huge disappointment for everyone. This is another reason that doctors like younger donors.
Hitting the age limit
I myself turned 61 in March. I’m no longer on the registry and I am righteously indignant about it. I started exercising 3 years ago and I have lost 20 pounds. I am in the best condition of my adult life. That nobody wanted me during the 20 years I was on the registry only further irritates me. But in reality, I would not be a good donor. There are more than 200 people with my HLA type on the registry and they are all younger than I am. So, there are other ways (in addition to doing my job) that I will be making a difference — and other ways you can, too. Contributing money or hosting a donor recruitment drive may not offer the same joy and satisfaction that the opportunity to donate marrow would, but these acts are crucial to saving more lives. I am also encouraging my son to join the registry. He is 18 and can be a member for a very long time. And it’s about time he did something that makes sense!