Thalassemia cured using cord blood stem cells
Jun 25th, 2009 | By editor | Category: Health, Science & Technology, Specials
Cord blood and bone marrow stem cells with a perfect tissue match from her one-year-old brother were used for transplantation
|Eight-year-old Thamirabharuni, holding her brother who donated the stem cells, did not suffer from rejection or graft versus host disease as the tissue match was perfect. — Photo: V. Ganesan
||Eight-year-old Thamirabharuni and her one-year-old brother Pugazhendhi share a special kind of bond not commonly seen among siblings. Thanks to her brother, Thamirabharuni no longer suffers from thalassemia disease.
The stem cells transplanted in March helped her get rid of thalassemia. And hundred days after the procedure, one can safely say that her disease has been cured.
The stem cells that were transplanted came from two different sources — her brother’s cord blood, which was harvested during the time of his birth, and his bone marrow. Stem cells from the bone marrow had to be transplanted as there was insufficient number of stem cells in Pugazhendhi’s cord blood.
In the absence of cord blood stem cells, about 200 ml of bone marrow would have been required. It is difficult to get this quantity of bone marrow from a nine-month-old baby.
The cord blood was collected by and stored at Chennai based LifeCell International Pvt. Ltd., a private cord blood bank.
So is it all over? “One has to be still careful. There is a risk of infection till the end of the first year [after transplantation],” said Dr. Revathy Raj, Consultant Paediatric Haemato Oncologist, Apollo Speciality Hospital, Chennai. Dr. Raj had done the transplantation for Thamirabharuni and two other cord blood transplantations for thalassemia before this.
The fact that patients are on immuno suppressing drugs for one year makes them vulnerable to infections. The risk of rejection of the transplanted stem cells, and the graft versus host disease (GVHD) reduce with time.
Thalassemia arises when red blood corpuscles (RBC) production is defective. A person suffers from the disease only when he inherits a defective gene from both parents. He becomes a carrier when he inherits a defective gene from only one parent. The diseased person has to undergo blood transfusion once every month for the rest of his life.
Though stem cells separated from bone marrow have been used for more than 30 years to treat thalassemia, and is a gold standard in treating the disease, cord blood stem cells are slowly becoming an attractive alternative.
Contrary to what is projected by some cord blood banks, doctors are very reluctant to use cord blood stem cells to treat thalassemia in the absence of a full tissue match.
“We need a 6/6 [perfect match] for thalassemia. Even a 5/6 match is not sufficient,” asserted Dr. Raj. And doctors refrain from using stem cells from unrelated donors, even if there is a perfect match.
Apart from infections, there are two major challenges from transplantation — graft versus host disease (GVHD) and rejection of the donated stem cells. “There is a 30 per cent chance of having graft versus host disease even when it is from a fully matched related (sibling) donor.” This risk increases to 50 per cent when it is from an unrelated donor, even if there is 6/6 tissue match.
Rejection rate becomes an issue even when there is a perfect tissue match. According to her, in the case of thalassemia, the rejection rate can be up to 20 per cent even with related donors, and up to 40 per cent in the case of unrelated donors.
But why should rejection and GVHD be an issue at all when there is a perfect 6/6 tissue match, and why should it be so high when stem cells are from unrelated donors?
“There are several minor HLA antigens that are not tested. So if we use stem cells from people belonging to some other ethnic background, there are greater chances of [minor] HLA differences,” Dr. Raj stressed. “And this causes rejection and GVHD.”
In general, greater the tissue match and higher the stem cell count in cord blood, lesser are the chances of rejection and GVHD.
“So why undertake procedures that are risky when thalassemia can be treated through monthly transfusions,” she noted.
Private banking of cord blood for use by the family therefore becomes important when one of the siblings is suffering from a disease that can be cured using it.
Despite the risk of rejection and GVHD, a less than perfect sample can be used to treat children suffering from life threatening diseases such as leukaemia and aplastic anaemia. This is where public cord blood banking gains significance.
There is a strong case for promoting public banks as depending solely on bone marrow samples will not be wise.
Even if a perfectly matched bone marrow donor is found, chances are that the person may no longer be interested in donating.
Collecting cord blood samples is easy, the number of samples that can be banked is limited only by resources, and samples can be made available at very short notice.
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Different diseases pose different challenges
Though he had studied only till eighth standard and works as a carpenter in a private company in Coimbatore, he can rattle out the details of the disease, names of drugs and the various processes involved prior to and after transplantation. Even a veteran doctor would be stunned by his knowledge.
Mr. Kumar came to know about his daughter’s condition when she was one-and-half-years old. And the struggle began. But fortunately there were many kind souls who helped and guided him at different stages. Friends, doctors, well wishers, anonymous donors, well, the list seems endless.
If Dr. Raj took care of transplantation, the Chennai based LifeCell International, a private cord blood bank, helped him in equal measure. “We waived the fee for processing and storing one-year-old Pugazhendhi’s cord blood sample,” said Mayur Abhaya, Executive Director of LifeCell.
The transplantation would have remained a dream but for Pugazhendhi’s tissue that perfectly matched Thamirabharuni’s. The little brother’s blood, which was tested five months after he was conceived, gave the first hope. He was not suffering from the disease. He was only a carrier. Tests done after his birth revealed that the tissue matched perfectly.
While he played a crucial role in curing his sister, he could not avoid making her a carrier too. Today, everybody in the family is a carrier.
Since it was a perfect tissue match and the donor was her sibling, Thamirabharuni did not face any rejection or graft versus host disease (GVHD) problems.
That is not the case with the Surya Mahesh. He was found to be suffering from acute lymphoblastic leukaemia (ALL) stage 3 when he was three years old. He underwent chemotherapy twice. The leukaemia relapsed after the therapy on both occasions.
Surya was not as lucky as Thamirabharuni. There was no relative with a good tissue match. Cord blood had to be procured from the U.S. and Dr. Raj did the transplantation in August last year. The cord blood stem cells, which had only 5/6 tissue match, cured his disease. But he had to battle a severe graft versus host disease.
“He developed rashes a week after the transplantation. It soon became severe. On the sixth day his skin started peeling,” said his mother. “It peeled off thrice. Soon his nails started falling off and he had severe loose motions.”
“We went through a very tough time. It was a big struggle,” she recalled. “But we came out of it.” Biopsy done in April this year tested negative and Surya celebrated his sixth birthday recently.