What Is T-Cell Acute Lymphoblastic Leukemia?

Acute lymphocytic leukemia (ALL) is a malignant tumor disease in which B-line or T-line cells originate from lymphocytes abnormally proliferate in the bone marrow. Abnormally proliferating primordial cells can accumulate in the bone marrow and inhibit normal hematopoietic function, and can also invade tissues outside the bone marrow, such as meninges, lymph nodes, gonads, liver, etc. China has conducted a survey of the incidence of leukemia, and the incidence of ALL is about 0.67 / 100,000. The incidence in oil fields and polluted areas is significantly higher than the national incidence. ALL childhood (0-9 years old) is the peak of onset, which can account for more than 70% of childhood leukemia. ALL accounts for about 20% of adult leukemias in adults. At present, the corresponding treatment plan based on the different biological characteristics of ALL has achieved good results. About 80% of children and 30% of adults can achieve long-term disease-free survival, and there is a possibility of cure.

Basic Information

English name

acute lymphoblastic leukemia, ALL

Visiting department

Hematology, pediatrics

Multiple groups

Children aged 0-9

Common causes

Etiology unknown, related to genetics, environment, genetic changes and other factors

Common symptoms

Anemia, fever, infection, bleeding, etc.

Contagious

no

Causes of Acute Lymphoblastic Leukemia

ALL, like other leukemias, develops and develops in hematopoietic progenitor cells or stem cells. At present, its etiology and pathogenesis are not completely clear, but it is related to some risk factors.

1. Genetic and family factors

Approximately 5% of ALL is associated with genetic factors. In particular, the incidence of leukemia increases in some patients with a genetic predisposition syndrome.

2. Environmental impact

Ionizing radiation has been affirmed as one of the causes of human leukemia, but the mechanism is unknown. Especially in the population exposed to nuclear radiation, the incidence of ALL has increased significantly. Chemical substances such as benzene and benzene analogs, alkylating agents are considered to be closely related to human leukemia.

3. Genetic changes

All ALL cells have acquired genetic changes, including changes in the number and structure of chromosomes, inversions, deletions, point mutations, and duplications.

Clinical manifestations of acute lymphocytic leukemia

ALL generally has an acute onset. Clinical manifestations are related to the proliferation and infiltration of leukemia cells.

Anemia

More than 80% of patients have anemia at the time of onset, and a small number of patients do not have anemia in the early stages, but anemia will occur as the disease progresses. It is manifested as fatigue, fatigue, palpitations, dizziness, etc. The degree of manifestation is mainly related to the severity of anemia and the rate of decline.

2. Fever and infection

There are many fevers in the onset of ALL, which are caused by the release of cytokines by leukemia cells, including interleukin-1 and interleukin-6, which cause reactive fever. Insufficiency of granulocytes and abnormal functions lead to infection. Infected areas include oral cavity, gums, lungs, skin and soft tissues, perianal, etc. If they are not controlled in time, they may develop into sepsis.

3. bleeding

Bleeding is a common manifestation and can occur in various parts of the body. Bleeding sites include: skin pitting, nasal bleeding, gum bleeding, menstrual bleeding in women, gastrointestinal bleeding, and even life-threatening central nervous system bleeding. Reason The decrease of platelet number and abnormal function are the main reasons. coagulopathy. The blood vessel wall was damaged by bacterial toxins infiltrated or infected by leukemia cells.

4. Organ and tissue infiltration performance

Lymph nodes, liver, and splenomegaly were seen in 70% to 80% of ALL patients. More than a quarter of patients with bone and joint pain, limb long bones and joint pain are more common. Especially children ALL are more common, often with pain onset, and even lame gait. 30% to 50% show tenderness in the middle and lower part of the sternum, which is highly specific. Central nervous system leukemia was significantly more in ALL than in other types of leukemia. More children than adults. Mild cases can be asymptomatic and need to be found in routine cerebrospinal fluid examination. Some patients show headache, vomiting, cranial nerve damage, blurred vision, mental disorders, drowsiness, seizures, etc., and can even be life-threatening.

5. testicular leukemia

ALL is more common in children, with occult testicular leukemia in 25% of boys. Showing painless swelling of the testicles and abnormal erection of the penis.

Acute Lymphoblastic Leukemia

Blood routine

More than 90% of patients have obvious hematological abnormalities at the time of diagnosis, and the severity of the abnormalities reflects the extent of leukemia cell invasion. Anemia is positive cells and positive pigmented. About 50% of the total number of ALL white blood cells increased, and the white blood cells were more than 50 × 10 ⁹ / L at the time of onset, suggesting a poor prognosis. Three-quarters of patients have thrombocytopenia. Most patients can see varying numbers of naive lymphocytes in peripheral blood smears.

Bone marrow

Most bone marrow cells are proliferative or significantly active. Bone marrow cells can be classified as 20% primordial lymphocytes, and there are some naive lymphocytes.

3. Cytochemical examination

ALL cells have specific positive particles in most cells when glycogen is stained, which is typically represented by coarse blocks. Peroxidase and Sudan black staining were negative.

4. Immunotyping

Different differentiation antigens on the surface of ALL cells can be used for diagnosis and ALL can be divided into different subtypes. It is valuable for judging prognosis and guiding treatment.

5. Cytogenetics and molecular biology

Clonal abnormalities can be detected in more than 90% of patients. With the development of molecular biology technology, abnormal fusion genes can be found through gene diagnostic technology. The test results not only support karyotype abnormalities, but also play a very important role in the diagnosis and treatment of ALL, biological behavior, prognosis judgment, and detection of residual leukemia cells.

Diagnosis of acute lymphocytic leukemia

ALL diagnosis currently uses cell morphology, immunology, cytogenetics, and molecular biology (MICM) diagnostic models. Classification uses the World Health Organization (WHO) 2008 standard.

According to the latest WHO classification criteria for acute leukemia, the ratio of primordial / naive cell lymphocytes in bone marrow smears 20% can be diagnosed.

According to different differentiation antigens on the surface of leukemia cells, immunological techniques can be used to diagnose and divide into different subtypes. Generally divided into T, B cell lines.

Acute Lymphoblastic Leukemia Treatment

The effect of children's ALL treatment has steadily improved over the past 50 years, and the 5-year event-free survival rate has reached 80%. Mainly the application of combined drug chemotherapy; improvement of supportive treatment; preventive treatment of central nervous system and group treatment of risk factors. Therefore, the treatment strategy for children with ALL is: induction remission therapy, consolidation and intensive therapy, maintenance therapy and shelter (including central nervous system and testis) treatment. Hematopoietic stem cell transplantation in children with ALL should be used in high-risk and relapsed patients.

Adult ALL treatment draws on the successful experience of children ALL, and the efficacy has also been significantly improved. The complete remission rate in the initial treatment can reach more than 70%, and about 30% of patients are expected to be cured. Adult ALL treatment is a whole, including the improvement of drug chemotherapy regimens; the enhancement of supportive treatments; the promotion of stem cell transplantation and the continuous application of new drugs to the market. It is also closely related to the strategy of reasonable selection of treatment according to ALL classification and disease risk stratification.

Induced remission

Induced remission is the use of chemotherapy drugs to minimize leukemia cells after the diagnosis of the disease to achieve complete remission.

2. Strengthen intensive treatment

After complete remission, there are still residual leukemia cells of varying degrees, which need to be further consolidated and strengthened with chemotherapy drugs.

3. Maintenance treatment

It is an integral part of treatment after complete remission and good results have been achieved in children with ALL.

4. Hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation is recommended for patients with suitable donors in adults, especially those with high risk factors.

5. Central nervous system

Any type of ALL emphasizes early prevention of the central nervous system, mainly by intrathecal injection of chemotherapy drugs. Especially in patients with diagnosed central nervous system leukemia, chemotherapy drugs should be actively injected intrathecally until the cerebrospinal fluid examination is normal. Cranial radiation therapy if necessary.

Prognosis of acute lymphocytic leukemia

There is some controversy about the prognostic factors of ALL. The main prognostic factors are:

Age

Mainly age in the child group remains an important indicator of prognostic risk. Remission rates and long-term survival in most adults decrease with increasing age.

2. Immunophenotype

Leukemia cell surface immunophenotype is an independent prognostic factor in the prognosis of ALL.

3. Cytogenetics

Chromosomal abnormalities are independent factors affecting prognosis.

4. The patient's initial response to chemotherapy is also an important indicator of prognosis