Introduction on Acute Lymphocytic Leukemia

Executive Summary

Acute Lymphocytic Leukemia (ALL) is a cancer of immature lymphocytes, the white blood cell involved in the immune system of the body. It is common in young children and adults older than 50, but people of any age can develop this type of cancer. The abnormal cells plug other cells in the bone marrow in people with Acute Lymphocytic Leukemia, which prevents the production of red blood cells that carry oxygen, platelets that help in blood clotting, and other types of white blood cells.

People suffering from ALL have health issues related to blood cells such as anemia, increased chances of bruises or bleeding, and infections as they do not have enough of the type of white blood cells called neutrophils. Unlike other cancer types, spreading Acute Lymphocytic Leukemia to other body parts does not mean the cancer is in an advanced stage. Acute Lymphocytic Leukemia is curable in most cases.

What is Acute Lymphocytic Leukemia?

Leukemia is a cancer of the blood. Leukemia begins when healthy blood cells change and grow out of control. Acute lymphocytic leukemia(ALL) is a cancer of immature lymphocytes ^​1​. Lymphocytes are a type of white blood cell in the immune system of the body. ALL is also called as acute lymphoid leukemia or acute lymphoblastic leukemia. Acute signifies that the disease starts and gets worse very fast. People with ALL typically need immediate treatment. ALL is very common in young children and adults older than 50, but people of any age can develop ALL.

Acute Lymphoblastic Leukemia (ALL) is a kind of blood cancer that originates in the spongy tissue in the bone marrow of the body. The word “acute” in ALL refers to the fact that the disease progresses rapidly and creates immature white blood cells, leaving no space for the mature cells that perform normal functions. This type of blood cancer affects the white blood cells called the lymphocytes. Acute Lymphoblastic Leukemia or the Acute Lymphocytic Leukemia. It is the most common type of cancer in children, and the chances of cure are higher, unlike in adults, for whom the chances of cure are comparatively low. 

Causes

Like most types of blood cancer, the major cause of Acute Lymphoblastic Leukemia is the genetic mutation in the body that causes the white blood cells to grow at an abnormally fast rate that crowds out the healthy white blood cells. These rapidly growing white blood cells are immature and do not perform the normal functions of a white blood cell. The root cause and reason for why the genetic mutation that turns normal cells into cancerous cells is still unknown. 

Symptoms

Since the onset of Acute Lymphoblastic Leukemia is relatively rapid, the symptoms are also severe and quick to appear. Symptoms of Acute Lymphoblastic Leukemia include bleeding of the gums and frequent and severe nosebleeds along with lumps and blood clots caused by swollen lymph nodes in and around the neck, abdomen, armpit, and groin area. Some of the other common symptoms include fever, shortness of breath, bone pain along with weakness, fatigue, and a general decrease in tiredness. 

Acute Lymphoblastic Leukemia in infants

Although ALL is more common in children, it is quite rare amongst infants. Studies in the USA show that less than 90 infants a year are affected by Acute Lymphoblastic Leukemia, which constitutes 3% of all childhood cases of ALL. Research shows that even the most prominent pediatric centers in the USA only see very few chances of ALL in infants less than a year old. 

Diagnosis of Acute Lymphoblastic Leukemia in infants

ALL infants are biologically completely different from ALL older children and are usually more aggressive. Diagnosing Acute Lymphoblastic Leukemia in infants involves a series of tests, including physical examination, analyzing the medical history of the patient, bone marrow aspiration and biopsy, and lumbar puncture. Bone marrow aspiration and biopsy is the sampling of the bone marrow tissue of the patient so that the cancer cells can be observed closely. This will help in providing a more accurate and tailored treatment to the patient. 

Treatment for Acute Lymphoblastic Leukemia in infants

 The most mainstream treatment for ALL in infants involves chemotherapy with various medicines, and in some cases, the patients receive bone marrow transplants or stem cell transplants. The doctors prefer to take an approach that analyzes the risk of relapse in a patient and adjusts the intensity of treatment according to those factors. There are a few factors that are considered before the treatment is given to the patient. This includes the level of response a patient will have to the treatment and the time they take to respond to the therapy.

The patients that take less amount of time to respond to treatment are the low-risk patients and their treatment is less intense than that of high-risk patients. The age of the patient is also a crucial factor. Since infants who are closer to the age of 1 respond better to treatment than infants who are younger than six months. The white blood cell count is also an important factor since a higher white blood cell count can cause a poorer response to treatment. Another critical factor is the MLL rearrangement in the genes of the infant. MLL rearrangement is a genetic alteration in the infant that reduces the response to treatment while increasing the chance of relapse in the patient. MLL rearrangement is observed in up to 80% of infants who are diagnosed with ALL.

Side effects caused by treatments

The side effects can vary according to the patients and the type of treatments that they receive. However, there are a few common factors that infants are more vulnerable to. Various infections, particularly affecting the respiratory system, toxic effects on the liver and kidney of the patient due to chemotherapy, and some damage to the central nervous system. While these side effects are typical in infants with ALL, the care team who observes the patient through the treatment will work with the families to reduce the impact as much as possible. They also monitor the treatment and take care of the side effects accordingly. 

 Further research on ALL

The survival rate of infants with ALL is less than 50%, while the risk of relapse is known to be high compared to other types of cancer. However, there is a lot of groundbreaking research now developing. This includes integrating various new ways of treatments that are less invasive along with traditional chemotherapy. The standard chemotherapy drugs that are used to treat ALL infants are being combined with newly evaluated drugs. This is being used in clinical trials to improve the quality and effectiveness of the medicine. 

About lymphocytes

Lymphocytes are formed in the bone marrow, the red, spongy tissue located in the inner part of the long bones. Lymphocytes are found in the blood, spleen, and lymph nodes. Healthy lymphocytes fight bacterial and viral infections. In people with acute lymphocytic leukemia, new lymphocytes do not develop into mature cells but stay as immature cells that are the lymphoblasts.

There are three different types of lymphocytes – B cells, T cells, and natural killer cells.

• B cells form antibodies.
• T cells help us fight infections by activating other cells in the immune system and destroying infected cells.
• NK cells fight microbes and cancer cells.

Around 85% of people with Acute Lymphocytic Leukemia have the B-cell subtype, and approximately 15% have the T-cell type. The NK-cell subtype is very rare.

About ALL

The abnormal cells plug other cells in the bone marrow in people with ALL. This prevents the production of cells ^​2​–

• Red blood cells, which carry oxygen
• Platelets, which are parts of the blood for clotting
• Other types of white blood cells

This means that people with ALL can have problems related to having too few healthy blood cells, including ^​3​–

• Anemia, from not enough red blood cells
• Increased chances of bruises or bleeding because of low platelet levels
• Infections as they do not have enough of the type of white blood cells called neutrophils that fight bacteria

Lymphoblasts can also collect in the lymphatic system of a person and cause swelling of the lymph nodes. Some cells may invade other organs in men, including the brain, liver, spleen, thymus, or testicles. Acute leukemia also has a high chances of cure.

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