--- title: Acute Lymphoblastic Leukemia (ALL) url: "https://www.yyhmedical.com/en/guide/blood/acute-lymphoblastic-leukemia" type: MedicalWebPage inLanguage: en-US --- # Acute Lymphoblastic Leukemia (ALL) > Acute lymphoblastic leukemia (ALL) is a blood cancer that develops from immature lymphoid cells. It is the most common type of leukemia in children but can also occur in adults. Advances in risk stratification, targeted therapy, immunotherapy, CAR-T cell therapy, and hematopoietic stem cell transplantation (HSCT) have expanded treatment options for people with ALL. ## Overview Acute lymphoblastic leukemia (ALL) develops when immature lymphoid cells, called lymphoblasts, grow uncontrollably. These abnormal cells accumulate in the bone marrow, interfering with the production of normal red blood cells, white blood cells, and platelets. Leukemia cells may also spread to the lymph nodes, liver, spleen, central nervous system (CNS), and other parts of the body. ALL is broadly classified as B-cell acute lymphoblastic leukemia (B-ALL) or T-cell acute lymphoblastic leukemia (T-ALL), depending on the type of lymphoid cell involved. Cytogenetic and molecular features, as well as response to treatment, vary among patients and play an important role in treatment planning and prognosis. ALL is most common in children, but it can also affect adolescents, adults, and older adults. ## Causes and Risk Factors The exact cause of ALL is not fully understood, and most patients do not have a single identifiable cause. Certain genetic and environmental factors may be associated with an increased risk of developing ALL, including: Previous treatment for another cancer, including certain types of chemotherapy or radiation therapy; Certain inherited genetic conditions or predispositions, such as Down syndrome; Exposure to certain chemicals, such as benzene; Inherited or acquired genetic changes that may increase susceptibility to leukemia. Having one or more risk factors does not mean that a person will develop ALL. Many people diagnosed with ALL have no known risk factors. ## Signs and Symptoms Symptoms of ALL are often related to reduced production of normal blood cells or the spread of leukemia cells. Common signs and symptoms may include: Fever or frequent infections; Fatigue, weakness, pale skin, or reduced exercise tolerance; Easy bruising, pinpoint red spots on the skin, nosebleeds, or other unusual bleeding; Swollen lymph nodes; An enlarged liver or spleen; Bone or joint pain; Loss of appetite or unexplained weight loss; Some patients may develop headaches, vomiting, or other symptoms if the central nervous system is involved. These symptoms are not specific to ALL. Blood tests, bone marrow examination, and other diagnostic tests are needed to determine the underlying cause. ## Diagnosis and Testing Diagnosing ALL usually requires several tests. A complete diagnosis cannot be made from a blood count or bone marrow morphology alone. Complete blood count (CBC) and peripheral blood tests: These tests measure white blood cells, red blood cells, hemoglobin, and platelets and may identify abnormal cells in the bloodstream. Bone marrow examination: Bone marrow aspiration and related tests are important for diagnosing ALL and assessing the number and characteristics of abnormal lymphoblasts. Immunophenotyping: Flow cytometry and other techniques are used to identify markers on leukemia cells and help distinguish B-ALL from T-ALL and other hematologic diseases. Cytogenetic and molecular testing: These tests identify chromosome and gene abnormalities associated with ALL and can help with disease classification, risk stratification, and selection of targeted therapies. Measurable residual disease (MRD) testing: Highly sensitive methods, including flow cytometry and molecular testing, can detect small numbers of leukemia cells that remain during or after treatment. MRD is an important tool for assessing treatment response, estimating relapse risk, and guiding subsequent treatment decisions. Depending on the individual situation, a lumbar puncture, cerebrospinal fluid testing, or imaging studies may also be performed to assess possible involvement of the central nervous system or other sites. ## Treatment Treatment for ALL is individualized according to factors such as age, B-ALL or T-ALL subtype, cytogenetic and molecular features, risk group, MRD status, previous treatment, and whether the disease is newly diagnosed, refractory, or relapsed. ### **Chemotherapy** Multi-agent chemotherapy remains an important part of ALL treatment. Treatment commonly includes induction, consolidation, and maintenance phases, with regimens adapted according to disease subtype and risk level. Central nervous system prophylaxis or treatment is also an important component of ALL therapy to reduce the risk of leukemia involving or recurring in the CNS. ### **Targeted Therapy** As the molecular biology of ALL has become better understood, targeted therapies have become an important option for patients with specific genetic or molecular abnormalities. For example, patients with Philadelphia chromosome-positive (Ph+) ALL may receive a tyrosine kinase inhibitor (TKI). Other molecular abnormalities may also provide opportunities for targeted treatment, depending on the results of molecular testing. ###  **Immunotherapy** Immunotherapy has become an important part of ALL treatment, particularly for B-ALL. For example, the bispecific T-cell engager blinatumomab directs T cells toward CD19-positive B cells, while the CD22-targeted antibody-drug conjugate inotuzumab ozogamicin may be used in selected patients with B-ALL. These therapies may be used for relapsed or refractory disease and, in selected settings, are increasingly being incorporated earlier in the treatment course. ###  **CAR-T Cell Therapy** Chimeric antigen receptor T-cell (CAR-T) therapy is an important treatment option for selected patients with relapsed or refractory ALL and has been most extensively studied and used in B-ALL. CD19 is a major target for CAR-T therapy in B-ALL. For patients who relapse after CD19-directed CAR-T therapy, including those with changes or loss of the target antigen, other approaches such as CD22-directed CAR-T therapy, sequential CAR-T strategies, or other treatments may be considered depending on the individual situation. CAR-T therapy for T-ALL remains an active area of clinical research, including approaches targeting CD7 and CD5. CAR-T therapy is not appropriate or necessary for every patient with ALL. Whether to use CAR-T therapy, which target to select, and whether hematopoietic stem cell transplantation is needed after CAR-T-induced remission depend on disease subtype, previous treatments, MRD status, relapse risk, and the patient's overall condition. ### **Hematopoietic Stem Cell Transplantation** Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important treatment option for selected patients with high-risk, relapsed, or refractory ALL and in other specific clinical situations. For some patients, chemotherapy, targeted therapy, immunotherapy, or CAR-T therapy may first be used to achieve remission. The decision about whether to proceed to allo-HSCT is then based on factors such as relapse risk, MRD status, donor availability, treatment response, and overall health. ALL treatment is therefore not simply a choice between chemotherapy, CAR-T therapy, and transplantation. Different approaches may be combined or used sequentially as the disease and treatment response evolve. ALL is a highly heterogeneous disease. Even among patients with the same diagnosis, cell subtype, genetic abnormalities, risk classification, MRD status, previous treatments, and treatment response may differ substantially. Treatment decisions should be made by a hematology team based on a complete clinical assessment. For patients with relapsed or refractory ALL in particular, the choice and sequencing of CAR-T therapy, targeted therapy, immunotherapy, and hematopoietic stem cell transplantation require individualized evaluation. ## Content attribution (YMYL) - Author: - Medically reviewed by: - Last reviewed: - First published: - Sources: - National Cancer Institute (NCI). Acute Lymphoblastic Leukemia Treatment (PDQ®)–Patient Version. Updated May 12, 2025. (https://www.cancer.gov/types/leukemia/patient/adult-all-treatment-pdq) - National Cancer Institute (NCI). Acute Lymphoblastic Leukemia Treatment (PDQ®)–Health Professional Version. (https://www.cancer.gov/types/leukemia/hp/adult-all-treatment-pdq) - National Cancer Institute (NCI). Childhood Acute Lymphoblastic Leukemia (PDQ®)–Patient Version. Updated April 15, 2025. (https://www.cancer.gov/types/leukemia/patient/child-all-treatment-pdq) - National Cancer Institute (NCI). Childhood Acute Lymphoblastic Leukemia Treatment (PDQ®)–Health Professional Version. (https://www.cancer.gov/types/leukemia/hp/child-all-treatment-pdq) > --- Original (HTML):https://www.yyhmedical.com/en/guide/blood/acute-lymphoblastic-leukemia This is a clean Markdown mirror for large language models; the original page is authoritative.