Bone marrow lymphocytes

Frazier, D., et. al., The thymus does not mediate 2,3,7,8-tetrachlorodibenzo-p-dioxin-elic-ited alterations in bone marrow lymphocyte stem cells, Toxicol. Appl. Pharmacol., 124, 242,1994. 

Bone marrow lymphocytic tumors ABLS-1 ABLS-140 e (leukogenic) Abelson virus (C-type RNA)... 

The Thy-1 antigen is a cell surface antigen found in mice and rats. The antigen is membrane bound and is one of a number of differentiation antigens which appear on bone marrow lymphocytes and early postnatal development. Thy-1 is the product of codominant alleles on chromosome 9 in mice, and all inbred mouse strains are homozygous at this locus and express either Thy-1.1 or Thy-1.2 antigens - We previously proposed that the allo-... 

There are undifferentiated stem cells of the blood elements in the bone marrow that differentiate and mature into erythrocytes, (red blood cells), thrombocytes (platelets), and white blood cells (leukocytes and lymphocytes). The production of erythrocytes is regulated by a hormone, erythropoietin (see the section on kidney toxicity), that is synthetized and excreted by the kidney. An increase in the number of premature erythrocytes is an indication of stimulation of erythropoiesis, i.e., increased production of erythrocytes in anemia due to continuous bleeding. 

In addition to antibodies, the immune system also consists of bone-marrow derived lymphocytes, or B cells, and T cells that come from the thymus gland, both of which (indirectly) produce antibodies. These cells, in turn, may be helped by helper cells (= H) and suppressed by suppressor cells (= S). Helper cells may be alarmed as to the presence of antigens by macrophages (= M) that eat the antigens and leave parts of their meal on their cell surface. 

A B lymphocyte is a specific type of white blood cell (leucocyte) derived from bone marrow stem cells. Each B lymphocyte expresses an immunoglobulin (antibody) specific for a particular antigen. Following antigenic stimulation, a B lymphocyte may differentiate and multiply into plasma cells that secrete large quantities of monoclonal antibody. 

This class of lymphocytes differentiates from immuno-logically incompetent hematopoietic stem cells of the bone marrow within the thymus - hence, the name thymus-dependent (T-) lymphocytes. Two major subclasses develop simultaneously, T-helper lymphocytes (Th) and cytotoxic effector lymphocytes (Tc). The cytotoxic T-lymphocytes (carrying on the surface the differentiation marker CD8) destroy cells, which cany their cognate antigen bound to MHC class I molecules on the surface by inducing apoptosis. From an evolutionary point of view Tc cells appear to have developed predominantly to cope with vims infections. As vituses can only replicate within cells, Tc eliminate them by destroying their producers. 

This is a humanized anti-CD52 monoclonal antibody. At present it is in clinical use after bone marrow transplantation and for the treatment of refractory chronic lymphocytic leukemia. 

The thymus is a lympho-epithelial organ, located within the upper thorax. One of its fimctions is the conversion of certain lymphoid hematopoietic precursor cells originating from the bone marrow into thymus-derived lymphocytes (T-cells). 

Podsakoff GM, Engel BC, Carbonaro DA, Choi C, Smogorzewska EM, Bauer G, Selander D, Csik S, Wilson K, Betts MR, Koup RA, Nabel GJ, Bishop K, King S, Schmidt M, von KaUe C, Church JA, Kohn DB (2005) Selective survival of peripheral blood lymphocytes in children with HIV-1 following delivery of an anti-HIV gene to bone marrow CD34(+) cells. Mol Ther... 

L Vova TS. 1984. [Study of the mutagenic effect of 5 promising pesticides in mouse bone marrow cultured human peripheral blood lymphocytes, and in the yeast Saccharomyces-cerevisiae.] Tsitol Genet 18 455-457. (Russian)... 

Adenosine deaminase deficiency is associated with an immunodeficiency disease in which both thymus-derived lymphocytes (T cells) and bone marrow-derived lymphocytes (B cells) are sparse and dysfunctional. Purine nucleoside phosphorylase deficiency is associated with a severe deficiency of T cells but apparently normal B cell function. Immune dysfunctions appear to result from accumulation of dGTP and dATP, which inhibit ribonucleotide reductase and thereby deplete cells of DNA precursors. 

A large number of cells are involved in the immune response and all are derived fiom the multipotential stem cells of the bone marrow. The predominant cell is the lymphocyte but monocytes-macrophages, endothelial cells, eosinophils and mast cells are also involved with certain immune responses. The two types of immunity (humoral and cell-mediated) are dependent on two distinct populations of lymphocytes, the B cells and the T cells respectively. Both the humoral and the cell-mediated systems interact to achieve an effective immune response. 

NK cells are a subset of lymphocytes found in blood and lymphoid tissues, especially the spleen. They are about 15 an in diameter, possess a kidney-shaped nucleus and have two or three large granules in the cytoplasm. They are derived from the bone marrow. NK cells have the ability to kill certain tumour lines and normal cells infected by virus. Killing by NK cells is not specific for viral antigenic epitopes, and is not restricted by MHC molecules. They do not possess CD3 but do express CD2, CD 16 and CD56, together with a low-affinity receptor for the Fc portion of IgG. 

Hematopoiesis is defined as the development and maturation of blood cells and their precursors. In utero, hematopoiesis may occur in the liver, spleen, and bone marrow. However, after birth, it occurs exclusively in the bone marrow. All blood cells are generated from a common hematopoietic precursor, or stem cell. These stem cells are self-renewing and pluripotent and thus are able to commit to any one of the different lines of maturation that give rise to platelet-producing megakaryocytes, lymphoid, erythroid, and myeloid cells. The myeloid cell line produces monocytes, basophils, neutrophils, and eosinophils, whereas the lymphoid stem cell differentiates to form circulating B and T lymphocytes. In contrast to the ordered development of normal cells, the development of leukemia seems to represent an arrest in differentiation at an early phase in the continuum of stem cell to mature cell.1... 

For all newly diagnosed patients with leukemia, an aspirate of the liquid marrow and a bone marrow core biopsy are obtained.5 Morphologic and cytochemical analysis of these samples distinguishes three subtypes of ALL (LI, L2, and L3) and eight subtypes of AML (M0-M7) as classified by the French-American-British (FAB) scheme. See Tables 92-2 and 92-3 for the FAB classification of acute myelogenous leukemia and acute lymphocytic leukemia. 

CLL is characterized by small, relatively incompetent B lymphocytes that accumulate in the blood and bone marrow over time. The exact cell of origin is controversial but has been described as an antigen-activated B lymphocyte.3... 

Bone marrow Must have at least 30% lymphocytes. 

A 72 year-old man presents to his primary care physician for his yearly check-up. He reports feeling fine over the past year. A physical examination appears normal, but the patient had an abnormal WBC count of 20 x 1 03/pL (20 x 1 09/L) with 80% (0.80) lymphocytes. The bone marrow examination reports 60% (0.60) lymphocytes, and the diagnosis of CLL is made. 

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