Numbers of lymphocytes

Interleukin 2 (IL-2) is a 15.5 kDa glycosylated protein produced by helper T-cells in response to an antigen and interleukin-1. Ligation of the IL-2 receptor (expressed by a number of lymphocytes) by IL-2 stimulates growth, differentiation and survival. 

Miller Scott (1985) reported marked reduction in thymus weight in rats fed dioctyltin dichloride for 8 or 12 weeks at a level of 75 mg/kg diet. Numbers of lymphocytes together with T cell subpopulations were reduced in treated rats, but no difference was seen in antibody response to sheep red blood cells in vivo. No evidence was foimd of in vitro cytocidal effects of dioctyltin dichloride on blood lymphocytes. Evans et al. (1986) dosed pregnant and non-pregnant rats for 3 weeks at 75 mg/kg diet and reported severe thymic atrophy and extensive vacuolation of reticuloendothelial cells in pregnant animals only. 

Hematology. Hemacytometers or electronic cell counters can be used to assess the numbers of lymphocytes, neutrophils, monocytes, basophils, and eosinophils in the peripheral blood, while changes in relative ratios of the various cell types can be assessed by microscopic differential evaluation. Similar evaluations can be... 

Clonal selection is the process by which only a limited number of lymphocytes are stimulated to replicate by an antigen. 

Because lymphocytes can express such a large number of different possible specificities, perhaps on the order of millions, there must of necessity only be a relatively small number that have a particular specificity. Thus, when a microbe invades the body, the total number of lymphocytes initially committed to recognizing the antigens that go to make up the microbial constitution are relatively small and must be expanded to obtain sufficient protection for the host. 

In addition, the binding of lymphocytes to endothelial cells in the capillaries that surround the follicles, which contain proliferating B-cells, could restrict the supply of oxygen, fuels and building materials to the proliferating cells. Thus the binding of a large number of lymphocytes occurs at a later position in the blood supply to the node. 

Leukocytes The administration of glucocorticoids to human subjects brings about lymphocytopenia, monocytopenia, and eosinopenia. In addition, glucocorticoids block a number of lymphocytic functions (Table 61.2). 

The potential association between the immune system and mood disorders has become a major topic of interest in biological psychiatry in the past decade. In general, three immune measures have been examined, namely white blood cell counts, functional measures of cellular immunity such as natural killer cell activity and immune cell markers as exemplified by human lymphoctye antigen (HLA). The cumulative data from these studies suggests that depressed patients have a decreased number of lymphocytes, reduced mitogen-induced lymphocyte proliferation and a reduction in the number of natural killer cells. However, this does not apply to all depressed patients. Furthermore, not all aspects of immune function... 

As an example it may be pointed out that poly(methacrylic acid) is physiologically active. It has been shown by Ormai and Palkovits (49) that under the influence of poly(methaerylic acid) the number of lymphocytes in the blood is increased and the immunization activity of the lymphocytes is intensified. 

As noted previously, Zn has an important role in numerous critical biochemical processes, including immunity. In addition to the positive effects of Zn supplementation, various antioxidant vitamins have been shown to stimulate the immune system. Thus, supplementation of elderly individuals with a combination of vitamins A, C, and E showed significant improvement in the following cell-mediated responses (P12) (a) increased total number of circulating T-cells (b) increased the number of helper (CD4+) T-cells (c) increased helper-to-cytotoxic cell ratio (CD4+ to CD8+) and (d) increased total number of lymphocytes in response to phytohemagglutinin. Others (M12), in a double-blind, placebo-controlled study of an elderly group supplemented with vitamin E, demonstrated (a) increased... 

Some perturbation of the reticulocyte numbers was observed, but values at days 3 and 5 did not differ from controls. Absolute numbers of lymphocytes and neutrophils did not differ from controls (no data shown). A slight anemia was observed at 4 and 8 weeks of treatment with 300 and 900 ppm benzene. Results showed minor changes in the stem and progenitor cells. CFU-E depression after 4 days of exposure was significant. There was a dose-dependent depression of colony forming cell numbers present at 4 and 8 weeks of exposure with a maximal effect at the level of CFU-E. Decreased CFU-E and BFU-E were observed in a companion study in which hybrid mice were exposed to 300 or 900 ppm benzene for the same period of time (Plappert et al. 1994b). 

Increased numbers of neutrophils can indicate bacterial infection, rheumatoid arthritis or a type of leukaemia. An increase in the numbers of lymphocytes occurs in lymphocytic leukaemia and decreased levels are found in AIDS and following steroid therapy. 

The liver contains large numbers of lymphocytes, which increase in number following tissue injury in response to cytokines and chemokines released by inflamed tissue. Most of the T cells within the liver are mature lymphocytes that have already been programmed to respond to antigen. This large resident population of mature lymphocytes acts as a form of immunological memory. 

The effect of low-dose irradiation of the immune system was investigated in mice (Ren et al, 2006). When a 0.2 Gy (20 rad) dose of x-irradiation was administered every other day for a total of four times, the number of lymphocytes yielded by the liver, spleen, and thymus decreased by 10 days, but increased above the level of the control mice by day 28. The population of NK cells dramatically expanded, especially in the liver where primordial lymphocytes were present. Functional and phenotypic activation of these cells occurred at the recovery stage, raising the possibility that an initial activation of macrophages by low-dose irradiation mediated the innate immune system (Ren et al., 2006). 

B-4) Adenosine deamina.se deficiency. This is associated with low numbers of lymphocytes, severe combined immunodeficiency disease, and sometimes liver disease. There is an overproduction of ATP and dATP, which leads to an imbalance that upsets the proliferatimi of immune cells. Gene replacement for this enzyme is under investigation. 

A rapid decrease in the number of lymphocytes, monocytes and eosinopliils best describes the mechanism of action of... 

Autoimmune hepatitis has no distinctive histology. The picture presented resembles that of chronic active hepatitis portal and periportal infiltration from some plasma cells as well as a high number of lymphocytes are in evidence, (s. figs. 33.1, 33.2) The lymphocytes are mainly of the T-cell type, whereby the ratio of subtypes CD4 CD8 is about 1 1. The lymphocytes demonstrate emperipolesis (= capable of infiltrating and surrounding other cells), (s. fig. 21.11) Hepatocytes often show... 

The adrenal corticosteroids have been extensively used to suppress many different aspects of the immune response. AU of the corticosteroids have similar mechanisms of action. They bind to specific corticosteroid binding proteins in the cytoplasm. These complexes are then transported into the nucleus where they bind to discrete portions of the cell s DNA. This binding results in derepression of regulatory genes and the subsequent transcription of new mRNA (Rhen and Cidlowski, 2005). Steroids inhibit the consequences of the immune response. They have several different actions in this regard. One of their most important effects is to transiently alter the number of circulating leukocytes. There is a rapid increase in the number of neutrophils and a concomitant decrease in the number of lymphocytes, monocytes, eosinophils and basophils (Krensky et al, 2005). 

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