The term leukemia is derived from Greek and means "white blood". Leukemia is characterized by failure to produce mature white blood cells. The cells overgrow uncontrollably, become too numerous and crowd out existing healthy cells. These abnormal white cells, referred to as "blasts" overpopulate the bone marrow and spill into the bloodstream.
Leukemic cell over-population impairs the marrow, which is then unable to maintain production of sufficient numbers of red cells, platelets and white cells. The net effect is anemia, bleeding and impaired infection-fighting capabilities.
As leukemic cells circulate throughout the blood and lymphatic systems, they infiltrate vital organs like the lungs, kidney, spleen and liver, which in turn become impaired, and malfunctioin. Often these organs become enlarged. Leukemic cells may even invade the tissues surrounding the brain and spinal cord by crossing the blood-brain barrier, a system of tightly meshed cells, which helps to protect the central nervous system.
As the disease progresses, blast cells flood the entire system, rendering a patient susceptible to fatigue and excessive bleeding, and causing every minor infection or injury to become a potentially hazardous condition.
Untreated, death occurs from bleeding, form the spread of infection or from organ failure.
There are two major forms of acute leukemia:
*Lymphocytic Leukemia which affect immature white cells of lymphoid lineage.
* Myelocytic Leukemia which involves the myeloid or precursor line.
In the chronic form of these diseases, the cells have reached a more mature stage of development.
Acute Lymphocytic Leukemia, then, specifically refers to a malfunction in the production of immature lymphocytes which would normally develop into mature T or B cells.
ALL consists of the following subtypes or groups:
*Common ALL, referred to as cALLa , the common ALL antigen, is a B-lineage lymphocyte with surface antigeneic markers, referred to as CD-10 in keeping with the international white cell nomenclature system. It occurs in approximately 71 percent of children and 50 percent of adults with ALL.
*Pre-B-Cell ALL is a less common B-cell lineage malignancy. It is antigeneically a CD-19 marker and occurs in 12 percent of all children with ALL.
*T-Cell ALL occurs primarily in older adolescents and young adults, with a slightly higher incidence among males. Overall, the incidence is approximately 12 percent. It affects immature stem cells which exhibit T-lineage surface markers characteristic of the T-cell line of development.
Even less common types include mixed lineage acute leukemia, which has both lymphoid and myeloid markers and Ph'ALL. Ph'ALL may represent the "blast phase" of a previously undetected chronic myelocytic leukemia, but some adults and children have Ph'ALL which is not related to chronic myelocytic leukemia.
*Null-Cell, or Undifferentiated ALL are essentially outmoded terms. As diagnostic studes improve, identification of the various subtypes has eliminated the use of generic or undifferentiated terminology.
These biological features of the leukemic cell are important prognostic factors. Identification also includes histologic aspects by the French-American-British classification (L1, L2, L3), histochemical staining (Tdt, PAS) surface markers (CD+), as well as both quantitative chromosomal analyses.
ALL is a life-threatening disease. Its advance is rapid, and, left undiagnosed and untreated, life expectancy is less than one year. However, treatment has extended and improved the quality of life for the majority of patients, many of whom appear to be cured.
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Here's What You'll Find in these pages
- The index to all of the links for Marissa's Story
- ALL (this page) - Part 1 of an explanation of exactly what Acute Lymphocytic Leukemia is
- ALL Part 2 - Part 2 of the explanation of what Acute Lymphocytic Leukemia is
- Marissa's Story - Part 1 of how it came about that Marissa was diagnosed with ALL
- Marissa's Story Part 2 - Part 2 of Marissa's struggle with ALL
- Photos - Marissa's Photo Album
- Photos 2 - Part 2 of Marissa's Photo Album
- Photos 3 - Jessica's Photo Album
- Photos 4 - Randy's Photo Album
LINKS TO OTHER PAGES OF MARISSA'S STORY
Marissa's Story Homepage
Part 2 of an explanation of Acute Lymphocytic Leukemia
Part 1 of Marissa's Story
Part 2 of Marissa's Story
Marissa's Photo Album
Part 2 of Marissa's Photo Album
Jessica's Photo Album
Randy's Photo Album
Email: angelmomt@aol.com