Increased plasma HIV type 1 RNA levels are associated with low levels of non-MHC class I-restricted cytotoxicity.
Explore the source record for details and available documents.
Cytotoxicity, Immunologic↗
Biomedical subjects
H Ullum
Publications and source records attributed to H Ullum.
Exercise-induced immunomodulation--possible roles of neuroendocrine and metabolic factors.
Acute muscular exercise induces an increased neutrophil count concomitant with recruitment of natural killer (NK), B and T cells to the blood as reflected by an elevation in the total lymphocyte count. Meanwhile, following intense exercise of long duration the lymphocyte count declines, non-MHC-restricted cytotoxicity is suppressed, but the neutrophil concentration increases. In relation to eccentric exercise involving muscle damage, the plasma concentrations of interleukin-1, interleukin-6 and the tumor necrosis factor are elevated. In this review we will propose a model based on the possible roles that stress hormones play a mediating the exercise- related immunological changes: adrenaline and to a lesser degree noradrenaline are responsible for the immediate effects of exercise on lymphocyte subpopulations and cytotoxic activities. The increase in catecholamines and growth hormone mediate the acute effects of exercise on neutrophils, whereas cortisol may be responsible for maintaining lymphopenia and neutrocytosis after exercise of long duration. Lastly, the role of beta-endorphin is less clear, but the cytokine response is closely related to muscle damage and stress hormones do not seem to be directly involved in the elevated cytokine level. Other possible mechanisms of exercise-induced immunomodulation may include the so-called glutamine hypothesis, which is based on the fact that skeletal muscle is an important source of glutamine production and that lymphocytes are dependent on glutamine for optimal growth. Furthermore, physiological changes during exercise, e.g. increased body temperature and decreased oxygen saturation may also in theory contribute to the exercise-induced immunological changes.
Catecholamines↗
Decreased short-term production of tumor necrosis factor-alpha and interleukin-1beta in human immunodeficiency virus-seropositive subjects.
Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were measured by ELISA in 4.5-h, lipopolysaccharide-stimulated whole blood cultures of 347 human immunodeficiency virus type 1-infected patients and 107 healthy seronegative controls. The production of TNF-alpha was decreased in both AIDS and non-AIDS patients, whereas the production of IL-1beta was decreased in AIDS patients only. The production of TNF-alpha and IL-1beta was positively affected by the concentrations of CD14+ monocytes and CD8+ lymphocytes; however, in patients, the concentration of CD4+ lymphocytes and the presence of AIDS had a negative effect on cytokine production as determined by multiple linear regression analysis. It is concluded that low whole blood cytokine production is mainly caused by low numbers of cells, but a functional defect may also exist.
Acquired Immunodeficiency Syndrome↗
Increased losses of CD4+CD45RA+ cells in late stages of HIV infection is related to increased risk of death: evidence from a cohort of 347 HIV-infected individuals.
OBJECTIVE: To examine changes in the distribution of CD4+CD45RA+ (naive) and CD4+CD45RO+ (memory) lymphocytes in various stages of HIV infection and the effect of these changes on disease progression. DESIGN AND METHODS: Expression of CD45RA+ and CD45RO+ on CD4+ lymphocytes was analysed by flow cytometry in a prospectively followed cohort of 300 HIV-infected individuals (median follow-up time, 2.90 years; range, 0.02-4.54 years) and in a group of 102 age- and sex-matched uninfected controls. Survival analysis was performed considering AIDS development and death as endpoints. RESULTS: The median CD4+CD45RA+/CD45RO+ ratio was 1.3 (25-75% quartiles, 0.9-2.4) in controls; it was increased to 1.8 (1.1-2.5) in 40 HIV-infected individuals with CD4+ cell counts > 500 x 10(6)/l (P < 0.05); it was similar at 1.4 (0.8-2.0) in 106 HIV-infected individuals with CD4+ cell counts of 200-500 x 10(6)/l; and it was decreased to 0.9 (0.5-1.4) in 154 HIV-infected individuals with CD4+ cell counts < 200 x 10(6)/l (P < 10[-6]). When fitted in a Cox model adjusting for the total number of CD4+ cells and age a lower concentration of CD4+CD45RA+ cells was associated with an increased risk of dying. The concentration of CD4+CD45RO+ cells was not significantly associated with AIDS or death in age- and CD4+ cell count-adjusted Cox models. CONCLUSIONS: This study confirms a selective loss of memory CD4+ cells early in HIV infection followed by increased loss of naive CD4+ cells in later stages of the infection. The loss of naive CD4+ cells seems to be important in the pathogenesis of terminal HIV infection.
CD4 Antigens↗
Increased circulating levels of interleukin-6 in HIV-seropositive subjects.
Explore the source record for details and available documents.
Acquired Immunodeficiency Syndrome↗
Defective natural immunity: an early manifestation of human immunodeficiency virus infection.
Cytotoxicity mediated by natural killer (NK) and lymphokine-activated killer (LAK) cells may be of significance in host defense against viral infections. This study included 347 patients infected with human immunodeficiency syndrome virus (HIV) type 1 and 110 controls. The NK cell activity, either unstimulated or stimulated with interferon-alpha (IFN-alpha) or interleukin-2 (IL-2), and the LAK cell activity were suppressed in patients, but the NK/LAK cell activity did not differ between patients with AIDS and patients without AIDS. However, the IFN-alpha-stimulated NK cell activity and LAK cell activity were reduced in patients with symptoms of HIV disease (CDCIV) when compared with asymptomatic patients (CDCII+III). When the data were analyzed by multiple linear regression, the percentage of CD4+ cells had a positive effect on these two parameters in patients without AIDS, whereas the percentage of CD4+ cells had no significant effect on unstimulated and IL-2-stimulated NK cell activity in these patients. In controls and AIDS patients, the percentage of CD4+ cells had no effect on NK/LAK cell activity in multiple linear models. The total number of CD16+ cells was low in patients compared to controls, whereas the percentages of CD16+, CD56+, and CD16+CD56+ were either normal or elevated. Therefore, the decrease in NK cell subpopulations did not contribute to the observed depression in NK/LAK cell activity in vitro. It is concluded that natural immunity is suppressed in HIV-seropositive patients primarily because of a qualitative defect of the NK/LAK cells. This qualitative defect includes a reduced responsiveness to IFN-alpha, which is progressive until the onset of symptoms, and possibly related to the loss of CD4+ cells.
Adult↗
Pentoxifylline therapy in HIV seropositive subjects with elevated TNF.
Tumor necrosis factor-alpha (TNF-alpha) is thought to induce cachexia in subjects infected with human immunodeficiency virus (HIV), and it has been suggested that HIV-seropositive patients would benefit from treatment with pentoxifylline, a known suppressor of TNF-alpha production. The purpose of the present study was to examine how pentoxifylline at a dose of 800 mg thrice daily would influence the cellular immune system in HIV-seropositive persons with elevated TNF-alpha. Six HIV-seropositive subjects with elevated amounts of TNF-alpha in plasma at least at two occasions were included in an open, controlled, randomized, cross-over study consisting of a 6 week treatment period and a 6 week control period. Blood samples were collected before and at the end of each period. Pentoxifylline treatment did not influence the concentration of plasma-TNF-alpha, subpopulations of blood mononuclear cells, the proliferative responses nor the natural killer (NK), and lymphokine activated killer (LAK) cell activities. Furthermore, pentoxifylline treatment did not influence the weight, temperature, well being, or tiredness of the subjects. However, the patients frequently reported gastrointestinal side effects. In vitro, however, pentoxifylline at suprapharmacological concentrations inhibited the blood mononuclear cell (BMNC) proliferative responses, NK, and LAK cell activities.
Adolescent↗
Effects of glutamine on the immune system: influence of muscular exercise and HIV infection.
Glutamine increased the proliferative response and the lymphokine-activated killer cell activity of blood mononuclear cells isolated from normal healthy subjects (n = 6) in a dose-dependent manner, with optimum at 0.3-1.0 mM. The relative fraction of CD3+, CD4+, CD8+, CD14+, CD16+, and CD19+ cells was not changed by glutamine at a concentration of 0.6 mM, except in the phytohemagglutinin-stimulated proliferation experiment where the fraction of CD4+, and therefore CD3+ cells, increased. The natural killer cell activity was not influenced by glutamine. Human immunodeficiency virus (HIV)-seropositive subjects (n = 8) who performed concentric bicycle exercise for 1 h at 75% of maximal O2 consumption had an overall lower phytohemagglutinin-stimulated proliferative response, compared with the HIV-seronegative control group (n = 7). The proliferation during exercise was lower in both the HIV-seropositive and the HIV-seronegative group. Addition of glutamine in vitro did not normalize the lower proliferation in the HIV-seropositive group or the attenuated proliferation seen during exercise in both groups.
Adult↗
Bicycle exercise enhances plasma IL-6 but does not change IL-1 alpha, IL-1 beta, IL-6, or TNF-alpha pre-mRNA in BMNC.
The present study investigated the effect of concentric exercise on cytokine plasma levels and cytokine pre-mRNA in blood mononuclear cells (BMNCs). Healthy young moderately trained men performed ergometer bicycle exercise for 1 h at 75% of maximal oxygen uptake. The levels of plasma interleukin (IL)-6 increased significantly during exercise, but plasma levels of IL-1 alpha, IL-1 beta, and tumor necrosis factor-alpha (TNF-alpha) were below the detection limit in most subjects. Pre-mRNA for IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha could be detected in BMNCs, but the amounts did not change in relation to exercise. These results indicate that, although the absolute number of monocytes increases during exercise and the percentage of CD14+/HLA-DR+ and CD14+/HLA-DR- monocytes increases after exercise, the increased plasma levels of IL-6 during exercise is not likely to be a result of activated monocytes in peripheral blood.
Adult↗
NK cell response to physical activity: possible mechanisms of action.
Natural killer (NK) cells are highly influenced by physical exercise. The possible important mechanisms behind exercise-induced changes in NK cell function are cytokines, hyperthermia, and stress hormones, including catecholamines, growth hormone, cortisol, and beta-endorphins. Infusion studies mimicking stress hormone levels in blood during exercise indicate that increased plasma-adrenaline accounts for at least part of the exercise-induced modulation of NK cell function. During moderate as well as severe acute exercise, the NK cell activity is enhanced, but severe exercise is followed by immunodepression, at least in part caused by prostaglandins. Elite athletes have at rest elevated NK cell activity. However, due to frequent severe exercise the NK cell function is often temporarily severely depressed. It is suggested that during the time of immunodepression microorganisms, especially virus, invade the host, whereby infections can be established. However, in those who perform regular moderate exercise the immune system will often be temporarily enhanced and this will protect these from infections.
Cytokines↗
The effect of acute exercise on lymphocyte subsets, natural killer cells, proliferative responses, and cytokines in HIV-seropositive persons.
Eight healthy men infected with human immunodeficiency virus, type 1 (HIV) and eight HIV seronegative age- and sex-matched controls exercised on a bicycle ergometer (75% of VO2max, 1 h). The percentages of CD4+, CD4+45RA+, and CD4+45RO+ cells did not change, whereas the absolute number of CD4+ cells increased twofold during exercise and fell below prevalues 2 h after. The neutrophil count increase was more pronounced after exercise in the controls compared with in HIV-seropositive subjects. The percent CD16+ cells, and the natural killer (NK) and lymphokine activated killer (LAK) cell activity increased during exercise, but this increase was significantly less pronounced in the HIV-seropositive group. The results suggest that in response to physical stress, HIV-seropositive subjects have an impaired ability to mobilize neutrophils, NK and LAK cells to the blood. Furthermore, because the total number of CD4+ cells, but not the percentage of CD4+ cells, changed in response to exercise, this study further strengthens the idea that the percentage of CD4+ cells is preferable to the number of CD4+ cells in monitoring patients seropositive for HIV.
Adult↗