What is "acute lymphoblastic leukemia"

n. a type of leukemia that affects the lymphocytes

n. acute leukemia characterized by proliferation of immature lymphoblast-like cells in bone marrow, lymph nodes, spleen, and blood; most common in children [syn: acute lymphocytic leukemia]

Acute lymphoblastic leukemia, also known as '''acute lymphocytic leukemia ''' or acute lymphoid leukemia (ALL), is an acute form of leukemia, or cancer of the white blood cells, characterized by the overproduction and accumulation of cancerous, immature white blood cells, known as lymphoblasts. In persons with ALL, lymphoblasts are overproduced in the bone marrow and continuously multiply, causing damage and death by inhibiting the production of normal cells (such as red and white blood cells and platelets) in the bone marrow and by spreading ( infiltrating) to other organs. ALL is most common in childhood, with a peak incidence at 2–5 years of age and another peak in old age.

The symptoms of ALL are indicative of a reduced production of functional blood cells, because leukemia wastes the resources of the bone marrow that are normally used to produce new, functioning blood cells. These symptoms can include fever, increased risk of infection (especially bacterial infections like pneumonia, due to neutropenia; symptoms of such an infection include shortness of breath, chest pain, cough, vomiting, changes in bowel or bladder habits), increased tendency to bleed (due to thrombocytopenia), and signs indicative of anemia, including pallor, tachycardia (high heart rate), fatigue, and headache.

About 6,000 cases are reported in the United States every year. Internationally, ALL is more common in Caucasians than in Africans; it is more common in Hispanics and in Latin America. Cure is a realistic goal and is achieved in more than 80% of affected children, although only 20-40% of adults are cured. "Acute" refers to the relatively short time course of the disease, distinguishing it from chronic lymphocytic leukemia, which has a potential time course of many years.

ALL was one of the first cancers for which an effective chemotherapeutic treatment was developed. Antifolates like aminopterin and methotrexate were developed in the late 1940s by Sidney Farber and Yellapragada Subbarow. At that time, a doctor did not need a patient's or parent's consent to try an experimental treatment as the Nuremberg code had not yet been signed. Desperate to save his patients, Farber initially tried folic acid supplementation as a treatment for ALL. This had disastrous consequences and he likely accelerated the children's deaths.