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

Blood counts of CD4 cells remain the best prognostic factor in patients infected with human immunodeficiency virus (HIV). However, the small number of infected cells contrasts with the importance of lymphocyte depletion. Several mechanisms might explain this depletion including: antibody-dependent cytotoxicity. Twenty to 50% of the antibodies produced in vitro by B lymphocytes are directed against HIV antigens, especially the gp120 and gp41 viral envelope antigen. If this cytotoxicity effect occurs in vivo, it could reduce of lymphocytes carrying the viral genome and partially explain the major lymphopenia in HIV-infected patients. It is not yet known whether the long-term effect of these antibodies is immunoprotective or deleterious, but they may play a protective role at least in the initial stages of the disease. autoimmunity. Sequence homology between the HLA II molecules and the glycoproteins of the viral envelope has been clinically and biologically documented in many manifestations of HIV infection. It has been suggested that alloreactivity, similar to the graft-versus-host reaction could be involved. In addition, programmed cell-death of the CD4 lymphocytes appears to be overactivated in HIV-positive subjects, possibly because the gp120 viral antigen perturbs the CD4-dependent signal for cell death. deleterious effects of cytokines. Tumour necrosis factor, for example, is known to play a role in the regulation of viral replication; it may favour the destruction of contaminated cells but also the initiation of provirus replication and integration into the cell genome. supra-antigens and/or infectious factors. Supra-antigenes, which can link with HLA molecules, are capable of oligoclonal activation without being "processed" in the cell presenting the antigen. This activation might affect cell death. Certain germ toxins could also play a role as cofactors. Cohort studies of asymptomatic HIV patients are needed to improve our understanding of these mechanisms. A therapeutic approach tailored to the stage reached by HIV-infected subjects will then be possible.
 ...
PMID:[Mechanisms of lymphopenia in HIV infection]. 790 32

We treated a patient with severe myasthenia gravis with a chimeric (murine/human) anti-CD4 monoclonal antibody (cM-T412) for 7 days and followed the therapeutic effect by standardized muscle function tests, single-fiber electromyography, and immunologic examinations of disease-specific B- and T-cell functions. Clinical and electrophysiologic improvement began within 4 days, lasted for 3 months, and was maximal between days 16 and 58. The CD4+ lymphocytes decreased to a minimum of 80 cells per microliters of peripheral blood, recovered slowly during the first year of follow-up, and did not correlate with changes in disease severity. T-cell stimulation by human acetylcholine receptor was abolished by the treatment but became detectable at the time of worsening of symptoms. The concentration of acetylcholine receptor antibodies in serum was not decreased by the treatment. The results suggest that anti-CD4 antibody administration could be effective in the treatment of severe myasthenia gravis and indicate that acetylcholine receptor-specific T lymphocytes might contribute to the disturbed neuromuscular transmission in the disease.
 ...
PMID:Treatment of myasthenia gravis with anti-CD4 antibody: improvement correlates to decreased T-cell autoreactivity. 793 6

The aim of this study was to assess the effects of zidovudine on B cell dysregulation in human immunodeficiency virus (HIV)-infected patients and the phenomenon of gp 120/anti-gp 120 antibody complex adhesion to CD4+ cells. Compared with pretherapy figures, zidovudine treatment was not associated with a change in spontaneous in vitro synthesis of anti-HIV antibodies but was related to restoration of lymphocyte ability to produce Epstein-Barr virus-specific antibodies in 43% of previously unresponsive patients. After 30 days of therapy, the percentage of circulating CD4+/IgG+ lymphocytes decreased; the number of available CD4 receptors per cell increased, and antibodies to gp 120, evident in CD4+ cell eluates from most untreated patients, were no longer detectable. These results indicate that zidovudine partly restores in vitro humoral responsiveness but does not substantially influence the overall activation of the B cell compartment. The findings also suggest that zidovudine may down-regulate some immunopathologic phenomena that amplify direct viral damage.
 ...
PMID:B and T cell function parameters during zidovudine treatment of human immunodeficiency virus-infected patients. 796 7

No single laboratory examination is diagnostic. On the other hand, such examinations support the diagnosis and aid in management of treated patients. In the serum, there is lymphopenia with a lowered CD4/CD8 ratio. An increase in beta 2-microglobulin and in the soluble IL-2 receptor reflect T lymphocyte activation. A classic observation is hypercalcaemia with hypercalciuria. The increase in angiotensin I converting enzyme reflects the body granulomatous mass. The results of bronchoalveolar lavage show the characteristics of the alveolitis associated with granulomatosis, accumulation of CD4+ T lymphocytes and activated alveolar macrophages. In practice, biochemical anomalies are of interest in the follow-up of treated patients.
 ...
PMID:[Biological tests in sarcoidosis: contribution to diagnosis and surveillance]. 798 99

Here we describe a case of unexplained CD4+ T-lymphocyte depletion and cryptococcal meningitis in a patient without evidence of human immunodeficiency virus (HIV) infection. This newly recognized syndrome has been named idiopathic CD4+ lymphopenia (ICL). When HIV infection is suspected in a patient with an opportunistic infection, a CD4+ lymphocyte count should be obtained, even if the patient's HIV test is negative. Patients with persistently low CD4 counts (< 300 cells/microL, or < 20%) who show no evidence of HIV infection, who have no defined immunodeficiency, and who are not receiving therapy associated with CD4 depletion have disease that meets the definition of ICL, and the case should be reported to the Centers for Disease Control.
 ...
PMID:HIV-negative "AIDS" in Kentucky: a case of idiopathic CD4+ lymphopenia and cryptococcal meningitis. 802 11

There is a complex relationship between malnutrition and immune function. Patients with chronic immunological disorders often become malnourished as a result of disease complications. On the other hand, macronutrient deficiencies are associated with the development of immunological deficiencies which are reversible on nutritional repletion. Deficiencies of macronutrients lead to diminished function of T and B lymphocytes in all patients, irrespective of HIV status. Lymphopenia is a characteristic finding in malnourished patients and includes loss of helper lymphocytes (CD4). This paper provides an overview of the gastrointestinal problems in AIDS and concludes that, because of the complex nature of the human immunodeficiency virus (HIV), a multidisciplinary team approach is essential, with the nurse playing a major role.
 ...
PMID:Gastrointestinal problems in patients with AIDS. 802 74

We treated 21 multiple sclerosis patients with two to four doses of cM-T412, a chimeric monoclonal antibody against the CD4 antigen found on helper/inducer T lymphocytes. The mean number (+/- standard error) of circulating CD4 lymphocytes decreased from 888 (+/- 81) cells/mm3 at baseline to 246 (+/- 18) after treatment. At 1 year after the last treatment, the CD4 count had recovered to only 335 (+/- 32). The antibody had no effect on CD8 lymphocytes, B lymphocytes, or other leukocytes. Side effects were minimal. Despite the prolonged depletion of CD4 lymphocytes, no opportunistic infections occurred. Only 1 patient had a possible allergic reaction. Most patients were clinically stable, but a few progressed. We conclude that repeated treatment with cM-T412 is effective in reducing the number of circulating CD4 lymphocytes and has no limiting side effects.
 ...
PMID:Repeated treatment with chimeric anti-CD4 antibody in multiple sclerosis. 805 54

Evidence is presented that a homeostatic mechanism exists that maintains a normal T-cell count, but is unresponsive to abnormalities in CD4+ T-cell count and CD8+ T-cell count. Specifically, we hypothesize that in all cases of T-cell loss, whether selective or not, both CD4+ T cells and CD8+ T cells will be produced until the absolute T-cell count returns to normal, even if this produces or exacerbates abnormalities in the absolute CD4+ T-cell count and absolute CD8+ T-cell count. This hypothesis implies that the selective loss of CD4+ T cells will induce the production of both CD4+ T cells and CD8+ T cells with the result that T-cell count will return to normal, but a persistent CD8+ T-cell lymphocytosis and CD4+ T-cell lymphopenia will be produced. To test this hypothesis, we monitored T-cell reconstitution in mice selectively depleted of CD4+ T cells through treatment with a CD4-specific monoclonal antibody (mAb). Consistent with our hypothesis, the absolute peripheral blood T-cell count in treated mice returned to that of controls after approximately 4 months. However, the absolute CD8+ cell count became 163% of controls and the absolute CD4+ cell count remained less than 63% of controls. Our hypothesis may have implications regarding the pathogenesis and treatment of human immunodeficiency virus (HIV) infection. In particular, the hypothesis implies that the unresolved CD4+ T-cell lymphopenia seen in the first several years of HIV infection is the "natural" consequence of the interaction of a selective CD4+ T-cell depleting virus and a nonselective T-cell replacing homeostatic mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:T-cell homeostasis: implications in HIV infection . 843 79

The objective of this prospective cohort study was to describe the natural history of hepatitis C virus (HCV) infection and the effect of human immunodeficiency virus (HIV) on the clinical manifestations of HCV liver disease. Two hundred twenty-three hemophiliacs were followed in a comprehensive care setting with periodic clinical and laboratory evaluations. Dates of HIV seroconversion were determined retrospectively from frozen sera. HCV assays were performed by a "second generation" four-antigen recombinant immunoblot assay (RIBA 2). Liver failure was found after a latency period of 10 to 20 years in 9% of multitransfused HCV-positive/HIV-positive adult hemophiliacs without an AIDS-defining opportunistic infection or malignancy. Lymphocytopenia, decreased CD4 counts, and, possibly, thrombocytopenia were associated with liver failure which appeared to be accelerated by HIV disease and its treatment. This form of severe liver disease is being seen with increasing frequency among multi-transfused persons with hemophilia who are coinfected with HCV and HIV.
 ...
PMID:Natural history of hepatitis C virus infection in multitransfused hemophiliacs: effect of coinfection with human immunodeficiency virus. The Multicenter Hemophilia Cohort Study. 809 52

Peripheral blood lymphocytes from 17 patients with autism were separated on a Ficoll-Hypaque density gradient. Patients had normal numbers of T and B cells and T cell subsets. Although CD4:CD8 ratios were normal for the whole group (2.09 +/- 0.97), 6 patients had elevated ratios (> 2.2) and 5 had decreased ratios (< 1.5). Mitogen-induced proliferation (concanavalin-A and phytohemagglutinin) was normal as was the autologous mixed lymphocyte reaction for the whole group. There was an abnormally increased percentage of DR+ (activated) T lymphocytes in 11 patients. With increasing age percentage of DR+ lymphocytes decreased. No patient had interleukin-2 (IL-2) receptor+ cells. Similar investigations performed on blood samples from 8 girls with Rett syndrome produced normal results. 11 of 17 autistic patients had an abnormally increased percentage of DR+ but not IL-2 receptor+ lymphocytes suggesting 'incomplete' activation, a finding which is seen in autoimmune diseases. The decrease in activated cells with increasing age suggests that there may be an autoimmune process which is more active earlier in life in a subset of autistics.
 ...
PMID:Lymphocyte function in autism and Rett syndrome. 812 18


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>