Evolution of the Treatment
Discoveries of thalassemia followed evolution of the medicine throughout years
The discoveries and the care involving thalassemia followed evolution of the medicine throughout years.
Until the 60's, the people with major thalassemia died before arriving at adolescence, because the benefit of the blood transfusion to avoid chronic anemia complications was not known.
Later, the problem that prevented many people with thalassemia from surpassing the 20 years of age started to be accumulation of iron in the organism caused throughout time by the transfusions and the own capacity of the gastrointestinal system of the thalassemic patient to absorb at most the mineral from the food. The excess overloaded the vital organs, such as the heart, causing diseases such as cardiac insufficiency, one of the main death causes.
In the 70's, upon appearance of the chelating agents, the category of drugs capable of "removing" the iron from the blood and eliminating it from the organism, the life expectation of the people with thalassemia who strictly followed the treatment TRANSFUSION + CHELATING AGENT started to be similar to that of any other healthy person.
Currently, some recent researches point out to a possible cure of the disease in the future. Among the treatment alternatives that intend to correct the source of the problem in the organism and encourage production of healthy hemoglobins, we may find the bone marrow transplant (TMO) and the genic therapy. Learn below the proposal of both interventions:
Bone marrow transplant (TMO)
Currently known better as hematopoietic stem cell transplant (TCTH), for the fact that, differently from most of the organ transplants, in this one the receiver receives, by endovenous means, the cells aspirated from the donor's bone marrow. The procedure which is apparently simple is aimed at, in case of the thalassemia, inhibiting the operation of the bone marrow of the thalassemic person and causing the donated cells to be fixed in this marrow and start to multiply, thus producing red cells carrying healthy hemoglobins. The problems are still the risks in the procedure, among them the development of the graft-versus-host disease – more aggressive than thalassemia itself --, when the new cells of the immunological system do not acknowledge the cells of the person with thalassemia who received the transplant (the host) and then start to destroy them, giving rise to an infection process. If it occurs, the transplanted person will need to take medicines during his/her whole life to contain the injuries occurring mainly in the skin, liver and the lungs. And not only.
An Italian study developed with over one thousand people with thalassemia and published in 2008 showed a mortality rate too high among the thalassemic people who submit to the transplant – ranging from 12% up to 40%. The death rates were larger among the adults, with ages above 16 years.
How to find a donor
The chosen one should have HLA (English acronym for Human Leukocyte Antigens) compatible to the thalassemic person – because these molecules have the function to acknowledge and differentiate own substances of the organisms and foreign agents, performing a core role to avoid rejection in the transplant. First of all, the donor should be searched in the family: there is a chance of 25% for finding him/her among siblings who are sons/daughters of the same parents – the larger the number of siblings, the greater the chance to find a donor. When it does not occur (that is, in 60% of the cases), the candidate to the transplant needs to recur to the Brazilian bone marrow donor record (REDOME) in the search for a voluntary compatible donor. The bone marrow transplant with non-relative donor is an even more risky procedure and should be well assessed considering all risks x benefits. Further information: click here.
Why to freeze the umbilical cord of the siblings of a person with thalassemia
Because, if the healthy sibling has a compatible HLA, and the person with thalassemia is a candidate to the bone marrow transplant (TMO), the cells for the procedure may be taken from the frozen umbilical cord, without the need to intern the donor.
Tip from the expert: Since, currently, thalassemia is a benign disease, which may be controlled by means of transfusions, drugs and medical monitoring, many experts are unanimous in not exposing the people with thalassemia – especially those who have iron overload in the heart – to the risks of the bone marrow transplant (TMO). If the person with thalassemia is a candidate to the TMO and wants to take the risk, however, the recommendation is for the procedure to be done with a compatible donor, before the 16 years of age and in centers highly specialized in the technique.
Centers especialized in transplants and collection of bone marrow in Brazil: AMEO
Genic or genetic therapy
Upon assistance of a vector (that may be an attenuated virus, that is, not capable of causing a disease), a new gene – called therapeutic gene – is inserted into the organism towards, in case of the person with thalassemia, chromosome 11 or 16 to correct the genetic mutation that leads to malformation of the hemoglobin and to chronic anemia. The goal is that, from such intervention, the bone marrow starts to produce healthy hemoglobins and that the disease disappears. The problem is that the few studies carried out with such therapy in case of thalassemia have not shown promising results – or the disease backs or the person with thalassemia dies.
The advancements in the biotechnology area as of the 80's caused the genetic therapy to be famous as the light in the end of the tunnel for several patients who suffer from rare, chronic, and incapacitating diseases. Unfortunately, most of the researches point out that the cure for some diseases is not so close yet as some scientists imagined – one of the main side effects pointed out has been the development of cancer among the patients who submitted to the procedure.