M. Kappel

Effects of in vivo hyperthermia on natural killer cell activity, in vitro proliferative responses and blood mononuclear cell subpopulations

This work was designed to test the hypothesis that elevations in body temperature of humans induce immunostimulalion. Eight healthy volunteers were immersed in a water bath (water temperature 39.5°C) for 2 h. during which their rectal temperature rose to 39.5°C. On a later day they served as their own controls, being immersed into thermoneutral water (34.5°C) for 2 h. Blood samples were collected before immersion, at body temperatures of 38°C, 39°C and 39.5° C, and 2 h after water immersion. The interleukin‐2 (IL‐2) enhanced natural killer (NK) cell activity (lysis per fixed number of mononuclear cells), as well as the proportion and total number of NK cells (CDI6+ cells), increased significantly during hyperthermia compared with control values. The lymphocyte proliferative responses did not differ significantly between hyperthermia and thermoneutral conditions. The proportion of pan‐T (CD3+) cells was maximally depressed 2 h after water immersion. The decreased proportion of CD3+ cells was mainly due to a decreased percentage of CD4+ cells (not significant). The proportion of B cells (CD19+ cells) did not fluctuate significantly, while a marked and significant increase in monocyte proportion (CD14+ cells) was found 2 h after hyperthermia. Two hours after hot water immersion the lymphocyte concentration declined while the neutrophil and monocyte concentrations were augmented. Induced hyperthermia causes signifi cantly increased serum cortisol. plasma norepinephrine and plasma epinephrine concentrations compared to controls. It is possible that the altered immune functions induced by elevated body temperature can be ascribed to altered composition and function of blood mononuclear cells induced by elevated levels of stress hormones.

Effects of elevated plasma noradrenaline concentration on the immune system in humans.

Abstract This study was designed to test the hypothesis that elevated plasma noradrenaline concentrations contribute to the exercise-induced modulation of the activity and percentage of the natural killer (NK) cells, and the leucocyte concentration. In a single blind, controlled, cross-over study, eight healthy men had noradrenaline infused for 1 h and achieved plasma noradrenaline concentrations comparable (20-fold increment) to those previously observed in cycle ergometer exercise (75% of maximal oxygen uptake for 1 h). The noradrenaline infusion increased the unstimulated, the interleukin-2 and interferon-α stimulated NK cell activity, and the percentage of CD16+ cells. The natural lytic activity per CD16+ cell however, did not change. The concentration of neutrophils, lymphocytes and CD16+ cells increased during the infusion. The neutrophil concentration remained elevated 2 h after infusion, at which time the lymphocyte count was back to normal. These results are comparable with the effects in the exercise model, and it is suggested that the augmented plasma noradrenaline concentrations, seen during extreme exercise, may participate in the exercise-induced immune changes.

The response on glucoregulatory hormones of in vivo whole body hyperthermia

This study was designed to examine the effects of in vivo hyperthermia on the circulating concentrations of a number of glucoregulatory hormones potentially involved in immunomodulation. Eight healthy male volunteers were immersed for 2 h in a hot water bath (water temperature 39.5 degrees C) (WI) during which period their rectal temperature rose to 39.5 degrees C. In a control study the subjects were immersed in thermoneutral water (water temperature 34.5 degrees C). Blood samples were collected before, at body temperature 38 degrees C (42.5 (30-52), median and range), minutes of hot WI, 39 degrees C (72.5 (58-97) minutes of hot WI), and 39.5 degrees C (at the end of 2 h of hot WI), as well as 1 and 2 h after cessation of 2 h of hot WI. In the control experiment blood samples were collected at identical time points. The growth hormone concentrations were elevated already at 38 degrees C to 24.2 (3.9-55.0) mU/l and peaked at 39 degrees C to 48.4 (20.8-81.5) mU/l compared to 0.3 (0.3-9.0) mU/l at baseline; at 39.5 degrees C the concentration declined to 31.6 (13.0-48.0) mU/l and further to 7.4 (0.8-17.3) mU/l 1 h after ending hot WI. The beta-endorphin levels were augmented at 39 degrees C and 39.5 degrees, to 8.0 (3.4-27.8) pmol/l and 8.1 (3.1-44.6) pmol/l, respectively, from 2.2 (0.7-5.6) pmol/l baseline. Glucagon levels raised from 23.0 (12.0-32.0) pmol/l to 32.0 (24.0-52.0) pmol/l at 39 degrees C, and to 38.5 (26.0-57.0) pmol/l at 39.0 degrees C. Insulin levels remained unchanged. Plasma glucose increased from 4.75 (4.2-7.6) mmol/l to 5.20 (4.6-5.6) mmol/l alone after 90 min of WI (temperature 39-39.5 degrees C). It is concluded that in vivo whole body WI hyperthermia increases the circulating levels of several essential glucoregulatory hormones.

Somatostatin attenuates the hyperthermia induced increase in neutrophil concentration

Abstract This study was designed to test the hypothesis that the immune changes seen during in vivo whole body hyperthermia are mediated by elevations in the plasma concentrations of either catecholamines, growth hormone or β-endorphins. Eight healthy volunteers were immersed in a hot water bath (WI; water temperature 39.5°C) for 2 h during which their rectal temperature rose to 39.5°C. In a single blind, randomized, cross-over study the stress hormone effects were blocked one at a time by administration of propranolol, somatostatin or naloxone; the results were compared to those obtained during saline infusion (control). Blood samples were collected before, at the end of 2 h of WI (body temperature 39.5°C), and 2 h later. Hormone blockade did not abolish the hyperthermia-induced recruitment of natural killer (NK) cells to the blood, and no influence was observed on the percentages or concentrations of any other subpopulations of blood mononuclear cells, except that the number of cluster designation (CD)3+ cells slightly increased after hyperthermia only in the propranolol experiment. Furthermore, the NK cell activity, both unstimulated and interferon-α or interleukin-2 stimulated, did not differ from the control situation. It is of interest, however, that somatostatin partly abolished the hyperthermia induced increase in the neutrophil number. Based on these data and previous results showing that growth hormone infusion increases the concentration of neutrophils in the blood, it is suggested that growth hormone is at least partly responsible for hyperthermia induced neutrocytosis.

Modulation of the counts and functions of neutrophils and monocytes under in vivo hyperthermia conditions

The present work was designed to examine the effect of in vivo hyperthermia on the cell number and functions of polymorphonuclear leucocytes (PMN) and monocytes in human beings. Eight healthy volunteers were immersed into a waterbath (WI) (water temperature 39.5 degrees C) for 2 h, whereby their rectal temperature rose to 39.5 degrees C. On a later day they served as their own controls, being immersed into thermoneutral water (34.5 degrees C) for 2 h. Blood samples were collected before immersion, at body temperatures of 38, 39 and 39.5 degrees C as well as 2 h after water immersion. The neutrophil count was significantly increased at 39.5 degrees C, as well as 2 h after hot WI, compared with control. The monocyte count was significantly augmented at 38 and 39 degrees C and 2 h after hyperthermic load. The FMLP-induced chemiluminescence response, for a given number of PMN, was significantly reduced 2 h after hot WI. The total amount (per litre of blood) of superoxide production by PMN stimulated with opsonized zymosan (OZ) was significantly augmented at 39 and 39.5 degrees C and 2 h after WI. In vivo hyperthermia did not affect the function of monocytes, but when correlated to the changes in the concentrations of monocytes (response per litre blood) a significant increase in the phorbol myristate acetate (PMA)- and OZ-enhanced superoxide production occurred at 38 and 39 degrees C, as well as 2 h after termination of hot WI. Furthermore the OZ-enhanced monocyte chemiluminescence response per litre of blood was significantly enhanced 2 h after hot WI.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of Minor Increases in Plasma Catecholamines on Natural Killer Cell Activity

This study was designed to test the hypothesis that the modulations of the human immune system in relation to in vivo whole body hyperthermia may be ascribed to elevations in the plasma epinephrine and norepinephrine concentrations. In a single-blind, controlled, cross-over study, 8 healthy volunteers were selectively infused norepinephrine and epinephrine, respectively, for 1 h, in order to obtain twofold increases in the plasma concentrations of these hormones, thereby mimicking the increases seen during in vivo whole body hyperthermia. Epinephrine infusion increased baseline, interleukin-2 and interferon-α stimulated natural killer cell activity, and the percentage and concentration of cluster designation (CD)16+ cells, whereas the neutrophil and lymphocyte count or the CD3+, CD4+, CD8+, CD19+ and CD14+ cell subtypes were not influenced. Norepinephrine infusion did not cause any changes in these variables. It is concluded that epinephrine, but not norepinephrine, may be responsible for the hyperthermia-induced effects on natural killer cells.

Cytokine production ex vivo: Effect of raised body temperature

This study was designed to examine the effects of hyperthermia in humans on the production of interleukin (IL)-1 alpha, IL-1 beta, tumour necrosis factor (TNF)beta and interferon (IFN)gamma, determined in supernatants from in vitro lipopolysaccharide or phytohemagglutinin stimulated blood mononuclear cells (BMNC), including the effect of indomethacin in the assays on these cytokines. Eight healthy volunteers were immersed into a hot water bath (water temperature 39.5 degrees C) for 2 h, during which their rectal temperature rose to 39.5 degrees C. On a later day they served as their own controls, being immersed into thermoneutral water (34.5 degrees C) for 2 h. Blood samples were collected before, at body temperatures of 38, 39 and 39.5 degrees C, and 2 h after water immersion and at corresponding time points in the control experiment. Hyperthermia did not influence the production of cytokines from stimulated BMNC. Indomethacin in the assays significantly enhanced the ex vivo production of TNF beta at hyperthermic and thermoneutral conditions; this indomethacin enhanced production of TNF beta declined from pre-value in the hyperthermia experiment compared to the control experiment. Furthermore, indomethacin augmented the production of IFN gamma from stimulated BMNC both in the hyperthermic and the control experiments; the indomethacin effect was, however, not different at the two conditions. It is suggested that hyperthermia alters the sensitivity of BMNC to prostaglandins.

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.

Immunological Effects of a Hyperinsulinaemic Euglycaemic Insulin Clamp in Healthy Males

The purpose of this study was to determine the in‐vivo and in‐vitro effects of insulin, at physiological and supraphysiological concentrations, on the human immune system. Ten healthy young men went through a sequential two‐step hyperinsulinaemic euglycaemic clamp. Plasma insulin concentrations were increased from baseline (9.0 μU/ml) to 49.1 μU/ml after 1 h of insulin infusion (step I) and to 1281 μU/ml (step II) after 2 h of infusion. As control experiments infusions of isotonic saline were performed. The unstimulated natural killer (NK) cell activity among blood mononuclear cells (BMNC) increased in response to supraphysiological plasma insulin levels (baseline versus step II: 20.6 ± 11.3 versus 27.8 ± 14.4%). The percentages of the CD16+ NK cells did not change, indicating an enhanced cytotoxic capability per individual NK cell. Insulin also slightly increased the activity of NK cells in vitro. A decline at step II in the concentrations of monocytes (0.29 ± 0.09 versus 0.12 ± 0.03 × 109/L), lymphocytes (1.57 ± 0.46 versus 1.22 ± 0.25 × 109/L), and CD16+ (24.2 ± 17.5 versus 16.7 ± 11.2 × 107/L), CD14+ (20.9 ± 10.8 versus 8.6 ± 3.9 × 107/L), HLA‐DR+ (37.2 ± 22.1 versus 19.2 ± 10.7 × 107/L) and CD45RO+ (91.6 ± 33.4 versus 61.7 ± 6.4 × 107/L) cells as well as in the percentages of CD14+ cells (11.2 ± 4.7 versus 6.4 ± 2.3%) and CD14+/HLA‐DR+ monocytes (9.7 ± 3.9 versus 4.8 ± 2.8%) were observed. No changes were found at step I. Hyperinsulinaemia did not change the percentages of the CD3+, CD4+, CD8+, CD19+, CD56+, CD11a+, CD45RO+ and CD45RA+ cells, the numbers of circulating immunoglobulin (Ig)G‐, IgA‐ and IgM‐ secreting cells, or the proliferative responses of BMNC to phytohaemagglutinin, purified derivative of tuberculin or interleukin (IL)‐2. Hyperinsulinaemia did not change the in‐vitro sensibility to insulin. In conclusion, supraphysiological insulin levels increased the activity of the individual NK cells, but decreased the numbers of NK cells, lymphocytes and activated monocytes. The findings are presumably of minor clinical relevance but may indicate an insulin‐induced immune activation.

Effects of Isoprinosine Treatment of HIV‐Positive Patients on Blood Mononuclear Cell Subsets, NK‐ and T‐Cell Function, Tumour Necrosis Factor, and Interleukins 1, 2, and 6

The immunomodulatory drug isoprinosine has been found to delay the occurrence of opportunistic infections in HIV‐infected individuals. To elucidate the mechanism of action, eight HIV‐positive, healthy patients were treated with isoprinosine, 3 g/day for 28 days; six patients received no treatment but were examined in parallel, and two patients were withdrawn. All patients had blood collected just before the start as well as on days 14 and 28 of isoprinosine treatment.