Host:

Bone marrow failure syndromes is a rare disease. It's often confused with general anemia and misdiagnosed as such. Although it can be treated with bone marrow transplantation, it also brings many complications.

Today we've invited Dr. Chow Tin-wai, Associate Consultant, Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital to explain it to us.

Hello, Dr. Chow. Can you share your expertise with us? What is bone marrow failure syndromes?

Dr. Chow Tin-wai:

First, I would like to introduce what is bone marrow. Bone marrow is in our bones. It contains our hematopoietic stem cells. We can imagine bone marrow as a factory that helps us make different types of blood cells. For example, red blood cells, white blood cells, platelets.

When we talk about bone marrow failure, it means that something has gone wrong in the bone marrow factory, so it cannot produce enough blood cells for our body to function properly. This syndrome includes many different diseases.

Host:

You just mentioned bone marrow is like a factory. There are red blood cells, white blood cells and platelets. What are these patients mainly lacking? What are the symptoms?

Dr. Chow Tin-wai:

In bone marrow failure syndromes, patients may lack one or more kinds of blood cells. For example, you may have heard of aplastic anemia, which refers to the condition where the bone marrow cannot produce blood cells and causes anemia. Anemia is related to insufficient number of red blood cells, which causes dizziness, fatigue, reduced ability to exercise. In children, it can lead to long term impact, such as affecting their growth and heart function.

Although it is called aplastic anemia, it's not just the red blood cells that are affected. For example, our white blood cells can be affected. White blood cells are important for our immunity. If your white blood cell count is too low, your resistance against pathogens will become weak. There's a high risk of infection, even some serious infections. Patients may have persistent fever.

There's more, our platelets. Our platelets help us to form blood clots. If we get hurt, platelets help us stop bleeding. So, when the platelet count is very low, there is a risk of continuous bleeding. Many patients may tell us that their skin bruises very easily, but there is no injury. These are subcutaneous hemorrhages caused by low platelets. In addition to this, bleeding can be severe, like when it occurs in the gastrointestinal tract or or even in the brain, and is dangerous. So overall, if a person has bone marrow failure, if it is in the severe range, it can be life-threatening.

Host:

But what causes bone marrow bleeding? Are people born with this or is it acquired?

Dr. Chow Tin-wai:

There are both inborn and acquired causes. Bone marrow failure syndromes consist of many different types of diseases. In fact, acquired causes are more common than hereditary diseases. For example, hereditary marrow failure syndrome is caused by some congenital, inherited genetic problems. There are errors in the genes which lead to impairment of the function of bone marrow to produce blood cells.

In these patients, with this rare disease, in addition to bone marrow, other organs may also be affected. There may be some special features. For example, growth delay, short stature, small head. They may look different from others. They may have some skeletal abnormalities. For example, there may be some abnormalities in the hand bones, or extra fingers. These can all be symptoms. Moreover, there can be problems with other organs, such as the heart, kidneys. These conditions may be present in some patients with inherited marrow failure syndromes, but not every patient has these conditions. So, there are different kinds of diseases.

In addition to inherited causes, we mentioned acquired causes are more common. Acquired cases may be related to environmental factors. For example, some patients have received chemotherapy drugs, or even radiotherapy, had some kinds of infection, or even cancer cells infiltrating the bone marrow. All these will affect bone marrow function.

But for most patients with bone marrow failure, an obvious cause cannot be identified, that's what we call "idiopathic". The environmental factors we mentioned before are usually not present. It is generally believed to be caused by the dysfunction of the immune system. Our body's immune system is supposed to help us to fight against diseases. But due to some errors, it mistakenly identifies hematopoietic stem cells as trigger and attacks them so that the stem cells so they can't produce blood normally.

Host:

What is the treatment for this disease? We often talk about bone marrow transplantation. Is it the primary treatment?

Dr. Chow Tin-wai:

If the bone marrow failure is in a severe degree, bone marrow transplantation would be considered. Apart from that, supportive treatment is very important. For example, if the immunity is weak, we need to treat infections urgently. Also, some patients have very low platelets count and very low red blood cells count. We need blood transfusions to keep them alive. So, I want to appeal to everyone here, please donate blood to save lives.

What we just mentioned are all symptomatic treatments. If you want to cure the root cause, one of the treatments we would consider is hematopoietic stem cell transplantation, or we call bone marrow transplant. The principle is to transfuse a healthy donor's hematopoietic stem cells into a patient. Hopefully, the stem cells will be successfully engrafted and can establish a new healthy hematopoietic system, so that it can provide normal blood production, restoring the bone marrow function. With this, we have a way to solve the problem of bone marrow failure.

But we need to note, if it is a congenital condition, because we know that in addition to bone marrow, there may also be problems in other organs. Bone marrow transplant is not able to solve problems in the other organs.

Host:

You mentioned bone marrow transplantation earlier. It all sounds simple and direct. But is there a big risk?

Dr. Chow Tin-wai:

Bone marrow transplantation is indeed not an easy thing. There are a lot of risks involved. Generally speaking, to receive a bone marrow transplant, we must prepare the patient so that the body can accept the new hematopoietic stem cell. Usually, it involves heavy doses of chemotherapy or some people may require radiotherapy. In these processes, the patient's original bone marrow cells will be eradicated. Under this condition, due to the high dosage of the drug, there are associated side effects. For example, patients may experience inflammation of the mucosa.

Another main risk involves the immunity. While old cells are cleared and new cells have not grown back yet, there is a window period of low immunity. The risk of infection is very high. We have to handle it very carefully. Patients must stay in very high standard bone marrow transplant ward.

When bone marrow stem cells are engrafted into the bone marrow, making a new system, there is also a risk that it will recognize the body as different from the original. It then attacks the patient's body. We call this graft-versus-host-disease. It can attack different organs. If it gets serious, it can be life-threatening. So we have to monitor and handle it very closely.

Host:

Thank you doctor for your sharing today. Let's wrap it up here. Goodbye.