Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inactivation of the klotho gene in mice results in multiple disorders that resemble human aging after 3 weeks of age. Because hematopoiesis, especially B lymphopoiesis, is affected in humans and mice by aging, we analyzed the hematopoietic state in homozygous klotho (kl/kl) mice. The kl/kl mice showed thymic atrophy and a reduced number of splenocytes. These mice had almost the normal number of myeloid cells, erythroid cells, IL-3-responsive myeloid precursors and colony forming units in spleen (CFU-S) in bone marrow (BM), but had a substantially decreased number of B cells in BM and peripheral blood as compared with wild-type mice. IL-7-responsive B cell precursors and all of the maturation stages of B cells in BM were also reduced. However, the function of hematopoietic stem cells including their capacity of B lymphopoiesis in vivo and in vitro was normal. Early B cell development was also normal in neonates and young kl/kl mice until 2 weeks old without aging phenotypes. RT-PCR analysis revealed that the level of IL-7 gene expression was significantly reduced in freshly isolated kl/kl BM cells. However, injection of IL-7 in kl/kl mice could not rescue the B lymphopenia. These findings indicate that Klotho protein may regulate B lymphopoiesis via its influence on the hematopoietic microenvironment.
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PMID:Impairment of B lymphopoiesis in precocious aging (klotho) mice. 1083 14

The innate immune response to intraportally infused adenoviral vector was evaluated in rhesus monkeys. A first-generation adenovirus-expressing lacZ (Ad-lacZ) was administered at a dose just below that which causes severe morbidity. The response to vector was evaluated for the initial 24 h following infusion. Clinical findings during this time were primarily limited to petechiae, consistent with the development of thrombocytopenia and biochemical evidence of disseminated intravascular coagulation. Serum transaminases were elevated and a lymphopenia developed. Tracking of fluorescent-labeled vector demonstrated distribution to macrophages and dendritic cells of the spleen and Kupffer cells of the liver. A systemic release of the cytokine IL-6 occurred soon after vector infusion. Analysis of splenic cells revealed acute activation of macrophages and dendritic cells followed by massive apoptosis. Bone marrow cultures demonstrated normal erythroid and primitive progenitors with a significant decrease in myeloid progenitors. Similar findings, except the abnormality in bone marrow cultures, were observed in monkeys who received an identical dose of Ad-lacZ in which vector genes were inactivated with psoralen and UV irradiation. These data suggest that inadvertent targeting of antigen-presenting cells following intraportal infusion of vector leads to a systemic cytokine syndrome which may be triggered by the viral capsid proteins.
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PMID:Activation of innate immunity in nonhuman primates following intraportal administration of adenoviral vectors. 1135 76

Seven, adult, female beagles were inoculated with a Swedish granulocytic Ehrlichia organism closely related to Ehrlichia equi and E. phagocytophila. Blood and bone marrow changes were evaluated throughout the acute phase of infection. All dogs developed moderate to severe thrombocytopenia during the parasitemic period. The mean platelet volume and platelet distribution width increased, and large platelets were seen on blood smears when platelet numbers were low. In bone marrow, absolute numbers of megakaryocytes and immature megakaryocytes were increased. These results suggested the thrombocytopenia was caused by increased platelet destruction. The dogs also developed mild, normocytic, normochromic anemia, with simultaneous decreases in serum iron concentration and total iron-binding capacity that resembled the anemia of inflammation. In bone marrow, there was a slight increase in immature erythroid cells and no erythroid hypoplasia; iron stores were normal to increased. Myeloid hyperplasia was seen in all infected dogs, despite neutropenia in peripheral blood. Lymphopenia occurred early in the parasitemic period, but lymphocytes responded strongly and numbers increased above baseline levels by the end of parasitemia. Blast-transformed lymphocytes (5% to 20%) were seen in peripheral blood for a few days. Experimentally-induced canine granulocytic ehrlichiosis caused cytopenias of short duration, coincident with the appearance of ehrlichial inclusions in neutrophils.
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PMID:Hematopathology in dogs experimentally infected with a Swedish granulocytic Ehrlichia species. 1207 39

Suboptimal nutriture causes leukopenia, but whether this is related to a modification in hematopoiesis is unknown. A 34-d period of zinc deficiency was used to obtain moderate and severely zinc-deficient (ZD) young adult mice whose bone marrow was evaluated for alterations in hematopoiesis, myelopoiesis and lymphopoiesis by flow cytometry. Expressions of CD31 (PECAM-1) and Ly-6C were used to identify changes in marrow population composition. Identity of marrow cells was confirmed with TER119, CD45R, Ly-6G and CD11b. Cells of the erythroid lineage declined as much as 60% depending on the degree of zinc deficiency, providing new insight into the early observations of clinicians that anemia accompanied ZD in humans. The lymphoid compartment also declined 50-70% with preferential losses among pre-B cells, an underlying cause of the lymphopenia that is a part of ZD, in which loss of pre-B cells was identified by CD43,CD45R, and immunoglobulin M. Conversely, cells of the myeloid lineage increased substantially in the marrow, both in proportion and absolute numbers in all ZD mice. Granulocytic cells increased 40-60%, whereas monocytic cells nearly doubled in ZD mice. These data suggest that there are important adaptations in hematopoietic functions as zinc becomes limiting. In the immune system, the precursors of phagocytic cells, which provide innate immunity, are protected, whereas precursors of lymphocytes, which provide adaptive immunity, are down-regulated. These findings illuminate the unique response of the marrow to a nutritional stress.
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PMID:Zinc deficiency in mice alters myelopoiesis and hematopoiesis. 1242 43

Differential expression of Hox genes is associated with normal hematopoiesis, whereas inappropriate maintenance of Hox gene expression, particularly Hoxa7 and Hoxa9, is a feature of leukemias harboring mixed-lineage leukemia (MLL) mutations. To understand the pathogenic roles of Hox genes in MLL leukemias, we assessed the impact of Hoxa7 or Hoxa9 nullizygosity on hematopoietic progenitor compartments and their susceptibility to MLL-induced leukemias. Selective reductions in the absolute numbers of committed progenitors, but not of hematopoietic stem cells, distinguished Hoxa7- and Hoxa9-deficient mice. Megakaryocytic/erythroid progenitor (MEP) reductions in Hoxa7(-/-) mice correlated with reticulocytosis and thrombocytopenia without anemia. Conversely, Hoxa9(-/-) mice displayed marked lymphopenia and substantial reductions of common lymphoid progenitors (CLPs) and lymphoid precursors, in addition to significant reductions of common myeloid progenitors (CMPs) and granulocyte/monocyte progenitors (GMPs). In retroviral transduction/transplantation assays, Hoxa7- and Hoxa9-deficient progenitors remained susceptible to transformation by MLL-GAS7, which activates MLL through a dimerization-dependent mechanism. However, Hoxa7(-/-) or Hoxa9(-/-) progenitors were less efficient in generating transformed blast colony-forming units (CFUs) in vitro and induced leukemias with longer disease latencies, reduced penetrance, and less mature phenotypes. Thus, Hoxa7 and Hoxa9 contribute to hematopoietic progenitor homeostasis but are not necessary for MLL-GAS7-mediated leukemogenesis, yet they appear to affect disease latency, penetrance, and phenotypes consistent with their critical roles as downstream targets of MLL fusion proteins.
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PMID:Leukemic transformation of hematopoietic progenitors by MLL-GAS7 in the absence of Hoxa7 or Hoxa9. 1507 Jul 2

Severe acute respiratory syndrome (SARS) is a new human infectious disease. The causative agent of SARS is a novel coronavirus (SARS-CoV). This report summarizes the hematological findings in SARS patients and proposes the possible mechanisms of SARS-CoV related abnormal hematopoiesis. Hematological changes in patients with SARS are common and include lymphopenia, thrombocytopenia and occasionally leukopenia. A significant decrease was also observed in peripheral CD4+ and CD8+ T lymphocyte subsets and it was related to onset of SARS. A number of potential mechanisms may be involved. The development of auto-immune antibodies or immune complexes triggered by viral infection may play a major role in inducing lymphopenia and thrombocytopenia. Moreover, SARS-CoV may also directly infect hematopoietic stem/progenitor cells via CD13 or CD66a inducing their growth inhibition and apoptosis. The receptor for group I and III CoV is aminopeptidase N (CD13). CD13 has been identified in human bone marrow CD34+ cells, platelets, megakaryocytes, myeloid cells, and erythroid cells, but not in lymphocytes. The common receptor for group II CoV is CEACAM1a (CD66a). CD66a is an adhesion molecule expressed on bone marrow CD34+ cells, platelets, granulocytes and activated lymphocytes. In addition, glucocorticoids could induce lymphopenia and the use of steroids may account for the decrease of lymphocytes in some SARS patients. The increased consumption of platelets and/or the decreased production of platelets in the damaged lungs are a potential alternative but often overlooked mechanism that can contribute to thrombocytopenia in severe critical pulmonary conditions.
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PMID:Hematological findings in SARS patients and possible mechanisms (review). 1525 84

Fat supplements, especially conjugated linoleic acid (CLA), are increasingly popular ergogenic aids among endurance athletes. To evaluate the importance of fat supplementation in the practice of endurance sports, we investigated the effects of CLA supplementation on body weight, muscle hypertrophy, peripheral blood composition, and bone marrow composition in healthy, young, endurance-trained mice. Young, healthy mice were subdivided into control, trained, and treated groups, according to their running attitudes. Training was performed over a period of 6 weeks on a treadmill, at a gradually increasing duration and speed. CLA-treated groups were gavaged with 0.425 mg x d(-1) CLA supplement for the entire training period. The exercise protocol induced a significant decrease in body weight (p < 0.003) and a consistent muscle hypertrophy (p < 0.003). A morphological evaluation of bone marrow from trained mice revealed an accelerated turnover of the erythroid lineage, i.e., a relative increase in proerythroblasts. Conjugated linoleic acid supplementation did not induce a further decrease in total body weights in either untrained or trained mice (p = 0.747), but induced a further increase in muscle hypertrophy in trained mice (p = 0.009). Furthermore, CLA feeding induced an important lymphopenia in peripheral blood of CLA-fed trained mice (p < or = 0.05). These findings suggest that CLA may improve the performance of endurance athletes by increasing muscle hypertrophy, and, at the same time, that it may cause oxidative stress damage, leading to a peripheral blood lymphopenia and a consequent neutrophilia as a defensive response. Despite the positive increase in muscle hypertrophy claimed by the pharmaceutics companies, we suggest that endurance athletes and those looking to improve their own skeletal muscle mass refrain from CLA supplementation, because it seems to intensify the oxidative stress caused by exhaustive exercise.
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PMID:Effects of conjugated linoleic acid and endurance training on peripheral blood and bone marrow of trained mice. 1731 69

There is dearth of information on the haematologic complications of HIV/AIDS in this country. The aim of this work was to evaluate the importance of peripheral blood and bone marrow changes in a population of adult Nigerians managed for symptomatic HIV infection at the OAUTHC, Ile-Ife, between 1995 and 2001. The study was prospective. Peripheral blood cells counts (haemetocrit value, total and differential leucocyte counts, and platelet counts) and bone marrow cytology of serologically confirmed HIV/AIDS patients seen within the study period were studied. The associated opportunistic disorder (s) was noted for each patient. Individuals with conditions that are ordinarily associated with haematologic disorders (e.g. cancer and inherited haemoglobinopathies) and patients diagnosed in pregnancy were not included. Significant levels of differences in mean values of blood cells within groups were determined by student's t-test. Seventy-two patients were recorded, out of which 49 (68%) were evaluable. There were 32 (65%) males and 17 (35%) females, all aged between 21 and 51 (median = 36) years. None of the patients had conventional antiretroviral therapy. Lymphopenia (lymphocytes < 2 x 10(9)/l) was seen in 64.4% of the patients, 50% and over 40% of the patients had moderate-severe anaemia and neutropenia, respectively. Blood cells values were not significantly different between patients with mild disease and those with moderate-severe diseases. The most characteristic marrow abnormality was the abundance of naked nuclei of megakarycytes in 20 (60.1%) of the patients. Dysplatic changes were evident in 15 (45.5%) of the bone marrow specimens studied. Such changes are characterised by dysgranulopoiesis, Pelger-Huet anomaly in some of the mature granulocytes, vacuolation of some erythroid and myeloid cells, unilobular micromegakaryocytes and megaloblastic erythroid precursors (15.1% of the marrow).
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PMID:Peripheral blood and bone marrow changes in patients with acquired immunodeficiency syndrome. 1805 Jul 79

Paclitaxel (single intravenous injection in a maximum tolerated dose of 4.6 mg/kg) to white outbred rats causes bone marrow hypoplasia, increased granulocyte and erythroid cell mitosis (metaphase-anaphase transition), and moderate pancytopenia developments in peripheral blood (hypoplastic anemia, deep, short-term neutropenia, lymphopenia and thrombocytopenia) in the first hours after injection. A considerable increase of polyploidy (4n) cells and a moderate increase in the structural changes (chromatid deletions) of chromosomes was observed on bone marrow metaphase plates in 24 h. The drug introduction causes earlier increase in the rate of thymus cells mitosis, a growth in the number of thymocytes with apoptosis signs, and a moderate decrease in the thymus and spleen weight. All changes are reversible. Long-term (90 days after injection) observation revealed decreased lymphocyte count in the peripheral blood and bone marrow and earlier thymus involution.
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PMID:[Myelotoxicity of paclitaxel (mitotax)]. 1807 42

Erythema infectiosum (fifth disease) is the most common clinical presentation of acute parvovirus B19 infection in infancy. In healthy adults, most cases of infection are asymptomatic or accompanied by a flu-like syndrome like headaches and myalgia. Haematological manifestations are dominated by transient aplasia of erythroid progenitor cells which remains asymptomatic in most of non immunocompromised patients. Patients with sickle cell disease, thalassemia or other disorders associated with shortened red blood cell survival are at particular risk for marked anemia or red blood cell aplasia. In immunosuppressed patients, anemia may be chronic because of persistent viral load. Neutropenia, lymphopenia or thrombocytopenia have also been reported in acute parvovirus B19 infection. Mechanisms of these cytopenias are not yet elucidated. We present two patients with thrombopenia and/or neutropenia but without anemia due to acute parvovirus B19 infection.
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PMID:[Neutropenia and/or thrombocytopenia due to acute parvovirus B19 infection]. 1941 Dec 38


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