Unexpected variation in immune genes poses difficulties for transplantation

August 3, 2012

the genes that allow our immune system to tell the difference between our own cells and foreign invaders – are evolving much more rapidly than previously thought, according to an article online on August 3 in Trends in Genetics. The resulting degree of variation improves our ability to fight off disease, but could also present challenges to current worldwide efforts aimed at identifying potential donors for patients undergoing stem cell transplantation.

"This new work makes clear the daunting and near hopeless challenge of keeping track of the continuous output from the HLA mutational spigot," says first author William Klitz, from the University of California, Berkeley.

HLA proteins sit at the surface of human cells. Every individual has a specific HLA on the surface of their cells and these proteins effectively act as an identification card. Any other that have the same HLA on the outside are recognized as 'self'; foreign particles like bacteria or viruses are identified as invaders and the kicks in to remove them. The same system that helps us fight off germs makes organ or stem cell transplantation difficult. Our bodies treat transplanted tissue as foreign and reject it. Unless, however, the patient and the donor share the same HLA . As a result, worldwide efforts are underway to identify all possible HLA variants, in the hopes of more effectively matching patients with potential donors.

The difficulty is that within the human population, HLA genes are mutating rapidly and Klitz estimates that more than a million variants exist in the current population. Trying to identify all the variants will be nearly impossible and ultimately pointless, according to Klitz, because of how quickly these genes are evolving. This rapid evolution is a boon in some ways because it means that, at the population level, our immune systems are getting better at fighting off pathogens. For transplant recipients, however, the most likely implication is that the best chance for a match will be found in first-degree relatives rather than in a worldwide search for donors.

Explore further: Transplant survival could be improved by altering present criteria for matching donors, recipients

More information: Klitz et al.: "New reservoirs of HLA alleles: Pools of rare variants enhance immune defense" Trends in Genetics, 2012.

Related Stories

Transplant survival could be improved by altering present criteria for matching donors, recipients

October 6, 2011
Selecting better matched recipients and donors than is currently required for umbilical-cord blood transplantation could substantially reduce transplant-related deaths. The findings, published Online First in the Lancet Oncology ...

Elimination of national kidney allocation policy improves minority access to transplants

July 21, 2011
A new study published in the American Journal of Transplantation reveals that since the elimination of the kidney allocation priority for matching for HLA-B on May 7, 2003, access to kidney transplantation for minorities ...

Study examines factors in pediatric kidney transplant rejection

July 18, 2011
Avoiding HLA-DR mismatching appears to be beneficial in pediatric kidney transplant patients, however the likelihood of finding a matching donor must be considered against the wait time for a possible donation, according ...

Recommended for you

How a poorly explored immune cell may impact cancer immunity and immunotherapy

November 17, 2017
The immune cells that are trained to fight off the body's invaders can become defective. It's what allows cancer to develop. So most research has targeted these co-called effector T-cells.

Asthma attacks reduced in tree-lined urban neighborhoods

November 17, 2017
People living in polluted urban areas are far less likely to be admitted to hospital with asthma when there are lots of trees in their neighbourhood, a study by the University of Exeter's medical school has found.

How the immune system identifies invading bacteria

November 16, 2017
The body's homeland security unit is more thorough than any airport checkpoint. For the first time, scientists have witnessed a mouse immune system protein frisking a snippet of an invading bacterium. The inspection is far ...

Can asthma be controlled with a vitamin supplement?

November 16, 2017
The shortness of breath experienced by the nearly 26 million Americans who suffer from asthma is usually the result of inflammation of the airways. People with asthma typically use albuterol for acute attacks and inhaled ...

Newly found immune defence could pave way to treat allergies

November 16, 2017
Scientists have made a fundamental discovery about how our body's immune system clears harmful infections.

Study finds asthma and food allergies predictable at age 1

November 15, 2017
Children at one year old who have eczema or atopic dermatitis (AD) and are sensitized to an allergen are seven times more likely than other infants to develop asthma, and significantly more likely to have a food allergy by ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.