Myelodysplastic syndrome is a disease of the blood. This pathology causes a drop in the number of circulating blood cells. This syndrome is also called: myelodysplasia.

In a “healthy” organism, the bone marrow produces different types of blood cells:

– red blood cells, allowing the supply of oxygen to the whole body;

– white blood cells, allowing the body to fight against exogenous agents and thus avoid the risk of infection;

– platelets, which allow blood clots to form and come into play in the coagulation process.

In the case of patients with myelodysplastic syndrome, the bone marrow is no longer able to produce these red blood cells, white blood cells and platelets normally. Blood cells are produced abnormally resulting in their incomplete development. Under these developing conditions, the bone marrow contains a collection of abnormal blood cells which are then distributed to the entire bloodstream.

This type of syndrome can either develop slowly or develop more aggressively.

 There are several types of the disease: (2)

• refractory anemia, in this case, only the production of red blood cells is affected;
• refractory cytopenia, where all the cells (red blood cells, white blood cells and platelets) are impacted;
• refractory anemia with excess blasts, also affecting red blood cells, white blood cells and platelets and leading to an increased risk of developing acute leukemia.

Myelodysplastic syndrome can affect people of all ages. However, the most commonly affected subjects are between 65 and 70 years old. Only one in five patients under the age of 50 would be affected by this syndrome. (2)

Most people with the disease have mild to mild symptoms at first. These clinical manifestations are subsequently complicated.

Symptoms of the disease are associated with the different types of blood cells affected.

In the event that the red blood cells are impacted, the associated symptoms are:

• fatigue;
• weaknesses;
• breathing difficulties.

In the event that the white blood cells are concerned, the clinical manifestations result in:

• an increased risk of infections linked to the presence of pathogens (viruses, bacteria, parasites, etc.).

When platelet development is concerned, we generally notice:

• heavier bleeding and the appearance of bruising for no underlying reason.

Some forms of myelodysplastic syndrome are similar to clinical manifestations that develop faster than others.

In addition, some patients may not present with characteristic symptoms. The diagnosis of the disease is therefore made after performing a blood test, demonstrating an abnormally low level of circulating blood cells and their malformation.

Symptoms of the disease are directly associated with the type of it. Indeed, in the case of refractory anemia, the symptoms developed will be essentially fatigue, feelings of weakness as well as the possibility of breathing difficulties. (2)

Some people with myelodysplastic syndrome can develop acute myeloid leukemia. It is a cancer of the white blood cells.

The exact origin of myelodysplastic syndrome is not yet fully known.

However, a cause and effect relationship has been put forward for exposure to certain chemical compounds, such as benzene, and the development of the pathology. This chemical substance, classified as being carcinogenic to humans, is widely found in industry for the manufacture of plastics, rubber or in the petrochemical industry.

In rarer cases, the development of this pathology can be associated with radiotherapy or chemotherapy. These are two methods widely used in the treatment of cancer. (2)

The risk factors for the disease are:

– exposure to certain chemicals, such as benzene;

– primary treatment with chemotherapy and / or radiotherapy.

The diagnosis of myelodysplastic syndrome begins with a blood test as well as the analysis of bone marrow samples. These tests help determine the number of normal and abnormal blood cells.

Bone marrow analysis is performed under local anesthesia. A sample of it is usually taken from the subject’s hip and analyzed under a microscope in the laboratory.

The treatment of the disease depends directly on the type of disease and the conditions specific to the individual.

The aim of treatment is to restore a normal level of circulating blood cells and their shape.

In the context where the patient presents a form of the disease with a low risk of transforming into cancer, the prescription of a particular treatment will not necessarily be effective but will only require regular monitoring through blood tests.

 Treatments for more advanced forms of the disease are:

• blood transfusion;
• drugs to regulate iron in the blood, usually after a blood transfusion has been performed;
• injecting growth factors, such as erythropoietin or G-CSFs, to boost the growth of blood cells and help the bone marrow produce blood cells;
• antibiotics, in the treatment of infections caused by a deficiency of white blood cells.

In addition, drugs of the type: anti-thymocyte immunoglobulins (ATG) or cyclosporine, reduce the activity of the immune system allowing the bone marrow to manufacture blood cells.

For subjects with a significant risk of developing cancer, chemotherapy may be prescribed or even a stem cell transplant.

Chemotherapy destroys immature blood cells by stopping their growth. It can be prescribed orally (tablets) or intravenously.

This treatment is often associated with:

– cytarabine;

– fludarabine;

– daunorubicine;

– clofarabine;

— l’azacitidine.

Stem cell transplantation is used in severe form of the disease. In this context, the transplantation of stem cells is preferably carried out in young subjects.

This treatment is usually combined with chemotherapy and / or early radiotherapy. After the destruction of blood cells affected by the syndrome, a transplant of healthy cells can be effective. (2)