Creating The Perfect Genetic Match

Super heroics to save lives

Published: Feb 16, 2010

Political correctness does not cut it here. Diversity is the anathema. Slight differences can be dangerous, even fatal. In the quest to find a stem cell donor for a patient who needs a transplant, it is all about matching for every racial, cultural or conceivable stereotype.  Siblings have a 25 percent chance to be perfect matches for one another and are the first source tested. Some people are not content to play the numbers game. They would rather play an active hand and create the perfect match.

Before we travel through genetic match-making, a quick refresher on why this is all relevant. Many patients with cancer go on chemotherapy to destroy their cancerous cells. While chemo does kill the bad cells, it can be a bit reckless and take out healthy cells too.  To replenish these healthy cells, patients are often given stem cell transplants following chemo. Stem cells are special cells with the retained ability to become any cell of the body. If chemotherapy is a forest fire set to kill some ravenous and deadly weeds, a stem cell transplant is the subsequent sprinkling of new seeds to reforest the burning green.

How good a match is tells us the genetic degree of fit between a donor and recipient. Finding (or creating) the right match is central to a successful stem cell transplant. The reason is pretty intuitive. The immune system in each of us is designed to thwart any attempts by foreign cells, such as bacteria or fungi, to lodge themselves in our bodies. If a stem cell transplant is done with donor cells that looks foreign (remember, no political correctness here), the host’s immune system will set into motion. What follows is a chronic condition called graft versus host disease where the host fights off the donor cells. Sounds a bit like what is happening to Indian nationals in some sunny parts of the world.

Apart from dialling down the immune system to let the donor cells engraft, physicians seek more ‘like’ cells. Perfectly matched cells will slip by the immune system of the host.  These cells are treated as part of the family and allowed to settle. Gradually they may take over the burnt-out host and give a patient a new lease on life.

What are the options for a child with a terminal disease and no close matches in the family? Some families decide to have another child through in vitro fertilisation or IVF.  IVF is a technique to fertilise sperm and eggs outside the body. The fertilised embryo is then implanted into the mother who goes on to have a normal pregnancy. To create a perfect match, parents go through IVF but select only those embryos that form a perfect match for their sick child. This process is called preimplantation genetic diagnosis and is approved in the UK at a handful of medical centres. Yes, people across the world are actually giving birth to save existing children from incurable diseases.

Many countries, including India, outright ban any form of prenatal diagnosis, as it can also be used to determine the sex and other genetic qualities of a child. 

There is a solution that would preclude the need to create the perfect match when there is none in the family. It is the development of a national matched unrelated donor programme. Dr. Mammen Chandy runs one of the main transplant programmes in the country at the Christian Medical College in Vellore. He confirms that in India stem cells are only collected for transplants when the donor and patient are related. Many countries such as the US have very successful programmes through which the public can submit their cell type that is then entered into a national database. If a patient needs a donor of the same type, the programme contacts the closest match and requests them to donate some cells.  
India should aspire to be a superhero, not a superpower. Stem cell transplants save lives. A national matched unrelated donor programme open to the world would be a pretty heroic thing to do.  

Dr Kumar, and our health team, can be contacted at health.forbesindia@network18online.com

 

(This story appears in the 19 February, 2010 issue of Forbes India. You can buy our tablet version from Magzter.com. To visit our Archives, click here.)

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  • Dr P Srinivasan Md

    Congratulations for a good article highlighting the role of ethnicity in finding a HLA match for stem cell transplant. Over the last 10 years blood forming stem cells from donated umbilical cord blood has become the preferred choice in the management of blood cancers and Thalassemia in children and young adults. We at www.jeevan are happy to have started a Public Cord Blood Bank in 2008 to address this gap. We have had three matches and one unit for released for a successful transplant in August 2011. As the commercial bankers advertise, we need a bank of blood forming stem cells for every Indian! Cheers

    on Mar 30, 2012
  • Dan Milner, MD

    An excellent article which is both timely and crucially important to improving any health system. The additional benefit of having a national program for stem cells is that it places, throughout a country, machines for collection of stem cells (apheresis) that also allow for the harvest of blood cell products (i.e., platelets, red blood cells, granulocytes) which can vastly improve the supply of life saving blood products which support any transplantation program as well as a host of diseases.

    on Feb 16, 2010
  • Jeffrey Blander

    This is a very timely and excellent article. With the increase in use of social media such as twitter and facebook, infiltration of mobile phone and sms services, the grassroots mechanisms to engage and empower people to register for bone marrow as well as other organ drives are now in place. These efforts can help save lives, reduce the anguish, and improve the odds of winning the 'medical lottery' faced by millions of families’ rich or poor, west or east, north or south. We are all citizens of a global world. An international registry and notification system is within our reach. Jeff Blander Co-leader Technology Innovation Working Group Harvard Initiative for Global Health (HIGH)

    on Feb 16, 2010
  • Allen

    Dr. Kumar has one critical challenge to his reasoning. It is wrong to assume that a more robust donor registry would preclude the need for some families to pursue pre-implantation genetic diagnosis. There are some diseases, like Fanconi anemia, which have dismal success rates with matched unrelated donors. Success skyrockets for transplants when they come from stem cells donated by matched sibling donors. Signing up more prospective donors is a life-saving and laudable goal - it just isn't the cure-all for all diseases that could be treated with stem cell transplantation.

    on Feb 17, 2010
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