Chronic Lymphocytic Leukemia - The Leukemia & Lymphoma Society

and/or manage the side effects. Generally, after 10 to 14 days, blood counts begin
to normalize and the side effects of the conditioning therapy begin to resolve. This
therapy is generally not performed for CLL. For more information about all types
of stem cell transplantation, see the free LLS publication Blood and Marrow Stem
Cell Transplantation.
Banding of Chromosomes. The staining of chromosomes with dyes that
highlight transverse bands or regions on the chromosome. The bands give the
chromosomes more specific features, allowing individual distinctions to be made
among them. This technique permits more precise identification of chromosomes.
See Fluorescence In Situ Hybridization.
Basophil. A type of white cell that participates in certain allergic reactions.
Beta 2-Microglobulin (B2M). A protein that is shed from CLL cells. The degree
of elevation of serum B2M appears to correlate with IgHv mutation status and
ZAP-70. A patient with a high ZAP-70 or an unmutated IgHv gene status is more
likely to have a high B2M level. This test to measure B2M is available in most
laboratories in the United States.
Blast Cells. The earliest marrow cells identified by the light microscope. Blasts
represent about 1 to 5 percent of normally developing marrow cells. They are
largely myeloblasts, which are cells that will develop into neutrophils. In normal
lymph nodes, blasts are usually lymphoblasts; that is, cells that are part of
lymphocyte development. In acute leukemias, and in some cases of myelodysplastic
syndromes (MDS), abnormal blast cells (abnormal myeloblasts) accumulate in the
marrow. This accumulation is associated with decreased function of the normal
marrow, leading to decreased numbers of red cells, neutrophils, and platelets in the
blood. The reduced number of cells, particularly of red cells, is responsible for the
symptoms of MDS and acute myeloid leukemia (AML).
Bone Marrow. A spongy tissue in the hollow central cavity of the bones that
is the site of blood cell formation. After puberty, the marrow in the spine, ribs,
breastbone, hips, shoulders and skull is most active in blood cell formation. In
adults, the bones of the hands, feet, legs and arms do not contain blood-forming
marrow. In these sites the marrow is filled with fat cells. When marrow cells have
matured into blood cells, they enter the blood that passes through the marrow and
are carried throughout the body.
Bone Marrow Aspiration. A test to examine marrow cells to detect abnormalities.
A marrow sample is usually taken from the patient’s hip bone. After medication
is given to numb the skin, the liquid sample is removed using a special needle
inserted through the bone into the bone marrow. The sample is looked at under
a microscope and assessed not only for the presence of leukemia, but also for how
much of it there is. The cells obtained can also be used for cytogenetic analysis, flow
cytometry and other tests.
page 30 I 800.955.4572 I www.LLS.org