B-lymphocytes functions

Infection is the most common cause of morbidity and mortality in MDS patients, accounting for 40-60% of deaths in various studies. The common infections are those normally associated with neutropenias, such as Gramnegative septicaemia and bacterial bronchopneumonias. Indeed, most MDS patients are neutropenic at some stage in their disease. Even those who do not have a neutropenia may have a defect in their neutrophil function. Many patients have clearly-defined defects in T- and B-lymphocyte functions, and variable defects in monocyte numbers or function have been described. Disorders of neutrophil function are common. Many reports indicate that phagocytosis, chemotaxis, respiratory-burst activity and degranulation are defective in some MDS patients, and hypogranulation is often observed. 

Endogenous histamine has a modulating role in a variety of inflammatory and immune responses. Upon injury to a tissue, released histamine causes local vasodilation and leakage of plasma-containing mediators of acute inflammation (complement, C-reactive protein) and antibodies. Histamine has an active chemotactic attraction for inflammatory cells (neutrophils, eosinophils, basophils, monocytes, and lymphocytes). Histamine inhibits the release of lysosome contents and several T- and B-lymphocyte functions. Most of these actions are mediated by H2 or H4 receptors. Release of peptides from nerves in response to inflammation is also probably modulated by histamine, in this case acting through presynaptic H3 receptors. 

Kohm AP, Sanders VM (2001) Norepinephrine and beta 2-adrener-gic receptor stimulation regulate Cd4-i T and B lymphocyte function in vitro and in vivo. Pharmacol Rev 53 487-525. 

Serum lysozyme/ C-reactive protein Phagocytosis/ ROS production NCC killing T/B-lymphocyte function... 

Dunier, M., A.K. Siwicki, J. Scholtens, S. Dal Molin, D. Vergnet and M. Studnicka. Effects of lindane exposure on rainbow trout (Oncorhynchus mykiss) immunity. III. Effect on nonspecific immunity and B lymphocyte functions. Ecotoxicol. Environ. Saf. 27 324-334, 1994. 

In vivo assessment of B-lymphocyte function involves immunizing the patient with a protein (e.g., tetanus toxoid) and a polysaccharide (e.g., pneumococcal polysaccharide vaccine) antigen to elicit and... 

C. B., Fujimoto, M., Tedder, T. F. CD22 regulates B lymphocyte function in vivo through both ligand-dependent and ligand-independent mechanisms. Nat. Immunol. 2004, 5, 1078-1087. 

Morikawa, K., Oseko, F. and Morikawa, S. (1993) Immunosuppressive property of bromocriptine on human B lymphocyte function in vitro. Clin. Exp. Immunol., 93, 200-205. 

Vitamin A appears to play a role in modulating a wide spectrum of immune responses, including T and B lymphocyte function, generation of antibody responses, function of other immune effector cells such as monocytes, neutrophils, and Langerhans cells, and maintenance of mucosal immunity. The role of vitamin A in immune function has been reviewed in more detail elsewhere [7-9]. Protective immunity to infectious diseases varies widely, and the role of vitamin A... 

Cell-mediated and humoral immunity are interdependent, that is, CMI influences the function of tiie B lymphocytes, and humoral immunity influences tiie function of the T lymphocytes. 

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. 

Lymphocytes are one of five kinds of white blood cells. Mature lymphocytes are astonishingly diverse in their functions. The most abundant of the lymphocytes are T lymphocytes (also called T cells) and B lymphocytes (also called B cells). 

In addition to the classical stress hormones already reviewed, several other hormones are augmented in response to stress. Stress-induced prolactin release is one of the most frequently studied examples. There is no doubt about the causal relationship between stress and increased pituitary prolactin release, but the biological meaning is much less clear (G2). This phylogenetically old hormone has been shown to have more than 85 different functions in all vertebrate species. However, besides its role in the induction of maternal lactogenesis, the physiological importance of prolactin is at present not fully established. Experimental and clinical evidence supports the view that prolactin is also an immunoregulating hormone (M44, R18). Prolactin receptors are present on human T and B lymphocytes (R18), and T lymphocytes depend on prolactin for maintenance of immunocompetence (B19). In addition, it has been shown that prolactin is able to influence the devel-... 

The primary function of the B lymphocytes is to produce antibodies, which are molecules that identify and lead to the destruction of foreign substances such as bacteria. The B lymphocytes and the antibodies they produce are responsible for humoral immunity. T lymphocytes provide immunity against viruses and cancer cells. These lymphocytes directly attack and destroy their targets by forming holes in the target cell membrane, causing cell lysis. The T lymphocytes are responsible for cell-mediated immunity. 

Lai, R.B., Kumaraswami, V., Steel, C. and Nutman, T.B. (1990) Phosphorylcholine-containing antigens of Brugia malayi non-specifically suppress lymphocyte function. American Journal of Tropical Medicine and Hygiene 42, 56-64. 

Benjamin, S. A., Jones, R. K., Snipes, M. B. and Lustgarten, C. S. (1975c). Comparative effects of inhaled relatively insoluble forms of "Y, l44Ce, and "Sr on canine peripheral lymphocyte function, page 90 in Radiation and the Lymphatic System, USAEC Report No. CONF-740930 (National Technical Information Service, Springfield, Virginia). 

IFN-y also directly modulates the immune response by affecting growth, differentiation and function of both T- and B-lymphocytes. These effects are quite complex and are often influenced by additional cytokines. IFN-y acts as a growth factor in an autocrine manner for some T cell sub-populations, and it is capable of suppressing growth of other T cell types. It appears to have an inhibitory effect on development of immature B-lymphocyte populations, but it may support mature B cell survival. It can both up-regulate and down-regulate antibody production under various circumstances. 

This drug has marked immunomodulatory effects and can alter the normal function of T and B lymphocytes, NK cells and macrophages, both in vivo and in vitro, in humans and animals (Table 30.1).910 Although the molecular and cellular mechanisms for these effects are not fully defined, it is believed that both receptor and non-receptor mechanisms are involved. Cannabinoid receptors (CBRs) are G-protein coupled 7-... 

The mechanisms of autoimmunity may also entail interaction with MHC structures determined by the HLA alleles. Individuals carrying certain HLA alleles have been shown to be predisposed to certain autoimmune diseases, which may account in part for the genetic variability of autoimmunity. In addition, metabolites of a particular drug may vary between individuals to confound the development of drug-induced autoimmunity. Dendritic cells, such as the Langerhans cells of the skin and B lymphocytes that function to present antigens to Th cells, express class-II... 

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