FRCPath (clinical Haematology), CCT (UK)
Haematology and stem cell transplant
Medanta-The Medicity, GURGAON
Thalassemias are a group of inherited disorders, which originated in the Mediterranean region. Generally, thalassemias are prevalent in populations that evolved in humid climates where malaria used to be endemic. Thalassemia affects all races, as thalassemias used to protect these people from malaria due to the blood cells’ easy degradation. The genetic defect in these conditions results in reduced synthesis of one of the components of hemoglobin. In most people this does not cause a problem and the state is called a carrier state. The problem arises when two carriers marry and their child ends up getting both genes defective causing thalassemia major.
Thalassemia major is a condition usually detected in early childhood. Affected children have growth retardation and need blood transfusions every 3 – 4 weeks resulting in iron overload. The prevalence of this condition in the society is hard to determine as most cases are in the developing world where there is a dearth of reliable information.
Treatment of this condition revolves around regular blood transfusions with its attendant risks and inconvenience. Apart from scarce availability of blood, the risk of infections, iron overload, and formation of antibodies make recurrent blood transfusions problematic.
What is the most effective intervention for thalassemia?
Probably the best example of the old adage “prevention is better than cure” is thalassemia major. Understanding the genetic and molecular basis of this condition has enabled us to apply this information to communities. The most effective intervention so far has been to screen the population to identify local- and ethnic-specific patterns of genetic abnormalities. To be useful, a screening program has to be coupled with an education program involving the local community leaders, affected population, and local doctors. The community and its leaders have to make sure facilities exist locally for necessary testing (genetic, if needed), genetic counseling, and prenatal testing. This has to be followed by the support of the general community members, social support, and community leaders that allows the affected couple to act on the available information and if needed terminate the affected pregnancy. Successful examples of community screening programs are Greece, Italy, and Cyprus where very few children with thalassemia major are now being born.
What are the treatment options for thalassemia?
Treatment of thalassemias varies according to the type of disease—from very little medical input in the minor versions to regular transfusions and iron chelation therapy in beta thalassemia major.
Prior to the advent of transfusion regimens, beta thalassemia major was a fatal disease a few months after birth. In the sixties, regular transfusion therapy transformed this condition into a chronic disease but the affected children would die in their second decade from complications of iron overload. Treatment to cut down the high iron levels (as a result of regular blood transfusions) in the body began in the 1970s and improved life expectancy.
What is the success rate of bone marrow transplant in thalassemia treatment?
Hematopoietic stem cell transplantation began in the 1980s and for the first time offered a cure from this dreadful disease, but this type of treatment can only be offered to a selected subset of patients. Over 3000 patients have undergone this procedure across the world. The rationale for performing a stem cell transplant is that it substitutes ineffective bone marrow producing abnormal cells which die early, with a normal system mitigating blood transfusion requirement. Bone marrow transplants in thalassemias are, therefore, a form of cell replacement therapy making it different from similar procedures in blood cancers.
The success rate of bone marrow transplant in thalassemia depends heavily on the iron levels in the body at the time of transplant. Good medical treatment with adequate blood transfusions and more importantly, optimal use of iron removing medication (chelating drugs) is the key to a successful transplant. Patients who have had good iron chelation treatment, a normal liver size, and no scarring of the liver can expect a 90% success rate from a bone marrow transplant.
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