HMG-1 as a late mediator of endotoxin lethality in mice.

Endotoxin, a constituent of Gram-negative bacteria, stimulates macrophages to release large quantities of tumor necrosis factor (TNF) and interleukin-1 (IL-1), which can precipitate tissue injury and lethal shock (endotoxemia). Antagonists of TNF and IL-1 have shown limited efficacy in clinical trials, possibly because these cytokines are early mediators in pathogenesis. Here a potential late mediator of lethality is identified and characterized in a mouse model. High mobility group-1 (HMG-1) protein was found to be released by cultured macrophages more than 8 hours after stimulation with endotoxin, TNF, or IL-1. Mice showed increased serum levels of HMG-1 from 8 to 32 hours after endotoxin exposure. Delayed administration of antibodies to HMG-1 attenuated endotoxin lethality in mice, and administration of HMG-1 itself was lethal. Septic patients who succumbed to infection had increased serum HMG-1 levels, suggesting that this protein warrants investigation as a therapeutic target.

Effects of perioperative recombinant human IFN-gamma (rHuIFN-gamma) application in vivo on T cell response.

In spite of the well-known immunoregulatory effects of recombinant human interferon-gamma (rHuIFN-gamma), in vitro clinical trials in trauma patients remain inconclusive. In vitro studies have shown that IFN-gamma has an effect on lymphocyte responses in addition to immunomodulatory effects on the monocyte/macrophage system. To investigate the in vivo effect of rHuIFN-gamma perioperatively on lymphocyte behavior in surgical patients, we studied 46 anergic patients undergoing major surgery. Treated patients (T, n = 24) received 100 microg rHuIFN-gamma subcutaneously (s.c.), and control patients (C, n = 22) received a placebo on preoperative days -7, -5, and -3 in a controlled, double-blinded placebo trial. Whole blood cultures were stimulated with mitogen on perioperative days, and cytokines were investigated in the supernatants. Interleukin-2 receptor (IL-2R) levels were significantly elevated in the treatment arm during the postoperative period (p < 0.05). The postoperative enhancement of IL-4 in C was completely attenuated in T (p < 0.05). IL-2 levels were elevated perioperatively in T but not in C. No significant effect of rHuIFN-gamma could be demonstrated on IL-10 or lymphocyte proliferation in vitro. From this pilot study, we conclude that preoperative in vivo immunomodulation of lymphocyte function with rHuIFN-gamma in anergic patients is effective. It improves immunoreactivity, as shown by elevated IL-2R levels. Elevated IL-2 and suppressed IL-4 levels indicate a shift toward a Th1-driven lymphocyte response.

Systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), multiple organ failure (MOF): are we winning the battle?

The problems of inflammation and infection leading to organ dysfunction and failure continue to be the major problems after injury and operations and with intensive care for many diseases and problems. When SIRS goes to MODS and MOF, the mortality becomes high, ranging from 30-80% depending on the number of failed organs. In spite of this, there have been recent exciting discoveries and contributions to patient care. A reasonable question then is, are we making progress and if so, can we document it? Are the incidence and mortality of MOF decreasing? The literature comparing care over some years suggests a decrease in ICU mortality in patients with severe organ failure, a decrease in elective surgical mortality, and improvement in the results of care and outcome for trauma patients. Review of problems occurring in sick and injured patients indicates that certain problems are decreasing in frequency, such as renal failure and ARDS after trauma, stress gastrointestinal bleeding, and abdominal abscesses, and these should improve outcome. There are a number of exciting therapies that help certain patients but not everyone. These controversies challenge us to focus on where and when there are positive benefits. Risk factors for MOF are addressed to focus on early intervention. The possibilities of multiple therapeutic agents are described. Finally, we describe and emphasize our recommendation to strive to prevent MODS and SIRS.

Evaluation of Fc-receptor positive (FcR+) and negative (FcR-) monocyte subsets in sepsis.

The monocyte/macrophage (Mphi is central in the regulation of the immune response in states of trauma and sepsis. Because monocyte subsets, characterized by expression of the Fc-receptor (FcR), were shown to play distinct immunologic roles in trauma, it was the objective of this study to assess insights into the functional role of FcR positive (FcR+) and negative (FcR-) subclasses in surgical sepsis. In a prospective study, peripheral blood Mphi from 20 septic patients and 10 healthy volunteers were evaluated on consecutive days after the onset of sepsis. FcR+/- subsets were separated by rosetting with antibody-coated human erythrocytes. Receptor expression and synthesis of proinflammatory cytokines were used to evaluate the functional role of these cells. We demonstrated a significant monocytosis (350%; p<.01) and suppression of human lymphocyte antigen (HLA-DR) expression (35%; p<.05). Synthesis of Interleukin-1beta (IL-1beta; e.g., Day 1: 230+/-30 pg/mL) and Interleukin-6 (IL-6; e.g., Day 1: 1920+/-350 U/mL) were significantly higher (p<.05) in FcR+ subsets than in controls (IL-1beta: 100+/-5 pg/mL; IL-6: 353+/-75 U/mL). Tumor necrosis factor-alpha (TNF-alpha) was elevated in FcR+ monocytes but did not reach a significant value. Interleukin-8 (IL-8) synthesis showed only on Day 1 and in controls significant differences in FcR+ and FcR- cells (Day1: FcR-: 19.6+/-4.1 nM; FcR+: 9+/-4.3 nM). Sepsis results in a significant shift toward FcR+ monocytes. This cell population is characterized by high proinflammatory cytokine synthesis. The extent of this shift seems to identify a group of high risk septic patients that might benefit from immunomodulatory therapy.

Hemofiltrate from patients with severe sepsis and depressed left ventricular contractility contains cardiotoxic compounds.

Myocardial dysfunction due to sepsis is common in patients with multiple organ dysfunction syndrome and is believed to be produced by inflammatory mediators. Some of these mediators may be eliminated by continuous hemofiltration, which is a standard procedure in an ICU for renal replacement therapy. This study was designed to directly compare the effects of ultrafiltrates from patients with sepsis (UFs) with ultrafiltrates from healthy volunteers (UFh) in well-characterized cardiomyocyte culture systems. Isovolemic hemofiltration (filtration rate: 2 L/h, polyamide membrane) was performed during 12 hours in 5 patients with severe sepsis (Elebute Score >20) and simultaneously reduced left ventricular contractility (left ventricular stroke work index [LVSWI] <30 g m/m2) and in 5 healthy volunteers. Inflammatory mediator concentrations (interleukin [IL]-1beta, IL-6, IL-8, tumor necrosis factor [TNF] alpha, C3a, and C5a) were measured in plasma and ultrafiltrate samples taken shortly after the beginning of the hemofiltration procedure. Cell culture experiments were done comparing UFs with UFh by using spontaneously beating or electrically driven neonatal rat cardiomyocyte cultures. UFs contained significantly higher amounts of IL-1, IL-8, and C3a when compared to UFh. Simultaneously, UFs induced a decrease in the contraction frequency of electrically-stimulated cardiomyocytes, whereas UFh had no effect. The cardiotoxic effect could be reversed by the addition of a high concentration (2.4 mM) of Ca++. Hemofiltration did not alter parameters of cardiac performance during 12 hours in patients with sepsis. UFs induced significant cardiotoxic effects in rat cardiomyocytes, whereas UFh showed no cardiotoxicity. Contact of blood with the hemofiltration membrane did not induce activation of cardiotoxic mediators. Significantly higher filtration rates may be required to improve left ventricular contractility in patients with sepsis by hemofiltration.

Pentoxifylline decreases the incidence of multiple organ failure in patients after major cardio-thoracic surgery.

We assessed the safety and efficacy of intravenous pentoxifylline [3,7-dimethyl-1-(5-oxohexyl)-xanthine] in patients at risk for developing multiple organ failure after major cardio-thoracic surgery in a single-center, randomized, placebo-controlled study. Of 816 consecutive patients who underwent major cardio-thoracic surgery, 40 who had Acute Physiology and Chronic Health Evaluation II score values > or = 19 at the first postoperative day after the surgery were included. Patients were randomized to receive either placebo (control; n = 25) or intravenous pentoxifylline treatment (pentoxifylline; n = 15) at a dosage of 1.5 mg/kg/h as an adjunct to standard supportive therapy. Main outcome measurements were duration of required ventilator support, intensive care unit stay, and incidence of renal failure. Thirty-seven patients were eligible for evaluation. No significant adverse events related to pentoxifylline treatment were observed. The duration of mechanical ventilation was significantly greater for control patients (8.3 +/- 3.1 days) compared with pentoxifylline-treated patients (3.1 +/- .9 days; p < .05). Patients treated with pentoxifylline experienced fewer days on hemofiltration (1.2 +/- .8 vs. 6.8 +/- 3.3; p < .05) and a shorter intensive care unit stay (5.2 +/- 1.1 vs. 11.4 +/- 3.1 days). There were no intergroup differences in mortality. Mortality was 33% in the pentoxifylline group and 36% among control group patients. In conclusion, supplemental pentoxifylline treatment may decrease the incidence of multiple organ failure in patients at risk of systemic inflammatory response syndrome after cardiac surgery. Additional studies are required to determine the validity of the observed effects.

Perioperative treatment with human recombinant interferon-gamma: a randomized double-blind clinical trial.

In spite of proven immunoregulatory effects in vitro of recombinant human interferon-gamma (rhIFN-gamma) in trauma, clinical trials remain inconclusive in such patients. To investigate the in vivo effect of rhIFN-gamma perioperatively in surgical patients we did a pilot study in 46 patients termed anergic by negative delayed-type hypersensitivity (DTH) skin test, who were undergoing major surgery (22 women and 24 men). They received 100 micrograms of rhIFN-gamma subcutaneously (treated [T]; n = 24) in a double-blind, placebo- (control [C]; n = 22) controlled manner on preoperative days -7, -5, and -3. Whole-blood cultures were stimulated on days -7, -1, 4, 7, and 10 for 12 h with or without LPS (1 microgram/mL). Mild side effects such as fever, headache, or chills were observed in 7/24 patients. No major complications occurred and no significant effect of rhIFN-gamma on HLA-DR, IL-1, and IL-8 was demonstrated. PGE2, TNF-alpha and IL-6 levels were elevated perioperatively in T. versus C. Neopterin, a metabolite of activated monocytes and macrophages, was significantly activated on days -1 (C: 7.6 +/- 1.2 versus T: 20.5 +/- 2.4 nmol/mL; P < 0.001), day 1 (C: 8.3 +/- 1.4 nmol/mL versus T: 24.9 +/- 2.8 nmol/mL; P < 0.001), and day 4 (C: 9.5 +/- 1.1 nmol/mL versus T: 16.0 +/- 1.8 nmol/mL; P < 0.05). Due to the overall lack of infectious complications during the investigation, no clinical effect was shown for rhIFN-gamma treatment. DTH skin testing failed to detect high-risk individuals in the patient population studied. In conclusion, we demonstrated in our pilot study that pre-operative immunomodulation with rhIFN-gamma in surgical anergic patients did not show severe side effects and modulated in vitro immunoresponse. A larger clinical trial in better-defined high-risk patients may show whether a reduction of infectious complications can be achieved.

Comparative analysis of transcription and protein release of the inflammatory cytokines interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) following major burn and mechanical trauma.

The precondition for the systematic modulation of host impairing behavior of hyperactivated monocytes following trauma is to fully understand the mechanistic basis of cellular dysfunction. It was the objective of this study to scrutinize the synthesis patterns and the level of regulation of the functionally related inflammatory cytokines interleukin (IL)-1 beta and IL-8 under stressful conditions. We compared the quantity of cytokine protein release in lipopolysaccharide-stimulated in vitro cultures of peripheral blood mononuclear leukocytes with the signal intensity of the corresponding detectable mRNAs. Fourteen patients with major burn or multiple trauma on consecutive days post-trauma and healthy volunteers were studied. We saw an almost identical pattern of synthesis for both monokines during the time of observation, with a considerable impairment until day 5 post-trauma and recovery thereafter. In contrast to IL-1 beta, a clear concurrence between mRNA signal intensity and the quantity of protein release was found in the majority of patients for IL-8. From these data we conclude that the launching mechanisms for the de novo synthesis for both monokines under stress differ greatly, with IL-8 being clearly regulated on the transcriptional level, whereas the downregulation of IL-1 beta occurs, most likely, on the post-transcriptional level.

Modulation of immune response by blood transfusion: evidence for a differential effect of allogeneic and autologous blood in colorectal cancer surgery.

Even though blood transfusion-associated immunomodulatory effects have been reported, the basic immune mechanism is still not understood. Data from studies on the clinical effects of allogeneic blood-induced immunosuppression are contradictory. However, there are indications that autologous blood transfusion is not immunologically neutral but has intrinsic immunomodulatory potential. Therefore we investigated in vivo different immunological mediators in 56 randomized patients of a study comparing autologous and allogeneic blood transfusion in colorectal cancer surgery. Soluble IL-2 receptor, which is an indicator of general immune activation and the following immunologic refractory phase, indicated immunosuppression was more elevated at the seventh postoperative day in patients with allogeneic transfusions (p = .013) and autologous transfusions (p = .0003). The immunologic determination of TNF-alpha showed a significant postoperative increase in patients with autologous transfusions only (p = .0031). However, postoperative increase of soluble TNF-receptors p55 and p75 was also significant in patients transfused with allogenic blood (p = .022; p = .0014). The response to tetanus toxoid vaccination, an indicator of humoral immunity, was higher in patients transfused with allogeneic rather than autologous blood (p = .082), whereas responses of patients with autologous transfusions were even lower than in nontransfused patients. The reciprocal was already found for cell-mediated immunity determined by epicutaneously tested delayed-type hypersensitivity-reactions. IL-10 levels, an indicator of cellular immunosuppression, were determined in 27 additional patients before operation, immediately postoperative, and at the seventh postoperative day. IL-10 was found elevated immediately postoperative in allogeneic (p = .011) and nontransfused patients only (p = .042). The data from this study substantiate recent findings of a different immunomodulatory potential of allogeneic and autologous blood transfusion. They furthermore support the hypothesis that autologous blood transfusion does not contain immunologically neutral effects of allogeneic blood, but itself exerts an immunomodulatory effect.

Successful restoration of cell-mediated immune response after cardiopulmonary bypass by immunomodulation.

The objectives of this prospective randomized trial were to quantify immunosuppressive effects of cardiopulmonary bypass, to identify mechanisms responsible for postoperative immunosuppression, and to investigate the effects of immunomodulatory intervention on these mechanisms. Sixty patients were studied after cardiopulmonary bypass. Immunomodulatory therapy consisted of the cyclooxygenase inhibitor indomethacin, which blocks the downregulating agent prostaglandin E2, and thymopentin, which enhances T-lymphocytic activity. Twenty patients each received indomethacin either alone or combined with thymopentin. Twenty patients served as the control population. Our in vitro studies showed a decrease of CD4+ helper/inducer T cells and interleukin-2 receptor expression on T lymphocytes, while CD8+ suppressor/cytotoxic T cells and monocytes increased. Additionally, a depression of interleukin-1 and interleukin-2 synthesis as well as concurrent low gamma-interferon serum concentrations could be documented. These results indicate a downregulation of cell-mediated immune response. As an in vivo correlate of the immunomechanistic alterations, patients demonstrated an impaired delayed-type hypersensitivity response to an antigen skin test battery. These changes in immunoreactivity could be successfully counteracted by the combined immunomodulatory regimen, whereas sole indomethacin treatment could only partially restore depressed host defense parameters. With this study we could demonstrate for the first time that human lymphocytic interleukin-2 synthesis, which represents the key event among forward regulatory immune mechanisms, can be protected via in vivo immunoaugmentatory therapy and that this therapy can successfully counteract immunosuppressive effects of cardiopulmonary bypass.

Functional analysis of monocyte activity through synthesis patterns of proinflammatory cytokines and neopterin in patients in surgical intensive care.

This study was designed to further differentiate monocyte behavior in critically ill patients with operative or accidental trauma. The patient population studied consisted of 39 patients (17 patients undergoing elective surgery [ES], seven patients with major multiple injuries [MI], and 15 patients in an acute septic state [S]). Immunologic parameters assessed included monocyte phenotyping with the monoclonal antibody LeuM3, measurement of the cytokines interleukin (IL)-1, IL-6, and IL-8 in lipopolysaccharide-stimulated in vitro cultures of mononuclear leukocytes (PBMCs), and determination of neopterin in gamma-interferon-stimulated in vitro cultures and corresponding serum samples. Serum neopterin levels were very high in S patients (89.0 nmol/L; p less than 0.05) compared with control values (4.6 nmol/L), with a rise to 16.4 nmol/L in ES patients on day 7 and 13.4 nmol/L in MI patients on day 7. The concentrations of gamma-interferon-induced neopterin in the supernatants of the PBMC cultures were elevated in all patient groups. Severe impairment of IL-1 synthesis was seen in MI and S patients. IL-8 synthesis (818 +/- 150 units/ml, control value) was also suppressed (p less than 0.05) in MI patients; the values were 135 +/- 65 units/ml on day 1,231 +/- 110 units/ml on day 3,347 +/- 131 units/ml on day 7, and 355 +/- 107 units/ml in S patients. The kinetic patterns of synthesis were comparable for IL-1 and IL-8 in all patient groups. Lipopolysaccharide-induced IL-6 synthesis (9.4 +/- 1.5 x 10(3) units/ml, control value) was significantly elevated in the PBMC cultures of all patient groups, with the exception of the early phase after accidental trauma. Maximum amounts of IL-6 synthesis after surgery were 19.6 +/- 7 x 10(3) units/ml in S patients and 19.0 +/- 2.2 x 10(3) units/ml in ES patients. These results demonstrate (1) the impairment of the functional capacity of circulating monocytes and (2) that the degree of functional impairment is proportional to the severity of the injury.

Effect of hemofiltration on hemodynamics and systemic concentrations of anaphylatoxins and cytokines in human sepsis.

OBJECTIVE: To determine whether hemofiltration (HF) can eliminate cytokines and complement components and alter systemic hemodynamics in patients with severe sepsis. DESIGN: Prospective observation study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: 16 patients with severe sepsis. INTERVENTIONS: Continuous zero-balanced HF without dialysis (ultrafiltrate rate 2 l/h) was performed in addition to pulmonary artery catheterization, arterial cannulation, and standard intensive care treatment. MEASUREMENTS AND MAIN RESULTS: Plasma and ultrafiltrate concentrations of cytokines (the interleukins IL-1 beta, IL-6, IL-8, and tumor necrosis factor alpha) and of complement components (C3adesArg, C5adesArg) were measured after starting HF (t0) and 4 h (t4) and 12 h later (t12). Hemodynamic variables including mean arterial pressure (MAP), mean central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output were serially determined. During HF, cytokine plasma concentrations remained constant. However, C3adesArg and C5adesArg plasma concentrations showed a significant decline during 12-h HF (C3adesArg: t0 = 676.9 +/- 99.7 ng/ml vs t12 = 467.8 +/- 71, p < 0.01; C5adesArg: 26.6 +/- 4.7 ng/ml vs 17.6 +/- 6.2, p < 0.01). HF resulted in a significant increase over time in systemic vascular resistance (SVR) and MAP (SVR at t0: 669 +/- 85 dyne.s/cm5 vs SVR at t12: 864 +/- 75, p < 0.01; MAP at t0: 69.9 +/- 3.5 mmHg vs MAP at t12: 82.2 +/- 3.7, p < 0.01). CONCLUSIONS: HF effectively eliminated the anaphylatoxins C3adesArg and C5adesArg during sepsis. There was also a significant rise in SVR and MAP during high volume HF. Therefore, HF may represent a new modality for removal of anaphylatoxins and may, thereby, deserve clinical testing in patients with severe sepsis.

Mechanisms of cytokine cascade activation in patients with sepsis: normal cytokine transcription despite reduced CD14 receptor expression.

BACKGROUND: Lipopolysaccharide causes activation of monocytes/macrophages with excessive secretion of cytokines resulting in hypotension and shock in patients with sepsis. Lipopolysaccharide may induce these responses by interacting with lipopolysaccharide-binding protein and then binding to the cell surface protein CD14 or by acting directly with CD11-CD18 on monocytes/macrophages. The role of CD14 and CD11-CD18 in the activation of macrophages with enhanced cytokine transcription in patients with septic shock remains to be determined. METHODS: To study this, heparinized blood was obtained from 16 patients with septic shock on days 0, 1, 3, 5, 7, and 10 and compared with 20 control patients. The expression of CD14 and CD11b on monocytes in whole blood was measured by direct immunofluorescence and flow cytometry. Moreover, whole blood was stimulated with lipopolysaccharide (1 microgram/ml) for 0, 1, 2, 4, 8, and 24 hours, and messenger RNA expression for tumor necrosis factor-alpha, interleukin-beta (IL-1 beta), and IL-6 was determined on isolated peripheral blood mononuclear cells with Northern blot analysis. RESULTS: Both CD14 expression and receptor density on monocytes from whole blood were markedly suppressed (-63% on day 3; p < 0.05) in the septic group compared with controls. Although CD11b expression was also decreased (-24% on day 1; p < 0.05), receptor density on monocytes was slightly increased in the septic group in comparison with the control group. Kinetics and intensity of messenger RNA expression for tumor necrosis factor-alpha, IL-1 beta, and IL-6 were similar in both groups. CONCLUSIONS: These data indicate that in patients with septic shock, lipopolysaccharide-mediated signaling and cytokine transcription are unchanged despite a significant reduction of CD14 expression and density on monocytes. Thus, lipopolysaccharide-induced activation of monocytes from patients with sepsis may occur through direct binding of lipopolysaccharide to the CD11-CD18 complex or other lipopolysaccharide receptors, whereas binding of the lipopolysaccharide-lipopolysaccharide-binding protein complex to the CD14 receptor may not play a pivotal role in sepsis.

Dynamics of immunoglobulin synthesis after major trauma. Influence of recombinant lymphokines.

Major mechanical trauma causes a severe suppression of B-cell differentiation and IgM synthesis in mononuclear leukocyte cultures. In this study the effect of recombinant lymphokines and physiologic T-cell supernatants on B-cell differentiation was investigated. The influence of potentially suppressing monocytes and positive regulatory T-lymphocytes was eliminated using purified B-cell cultures. Antigen-induced IgM synthesis was reduced on all days following trauma. Addition of recombinant interleukin 2 or T-cell supernatant enhanced but did not restore IgM synthesis. Although recombinant interleukin 4 and recombinant interferon gamma had a suppressive effect on IgM synthesis in controls, both lymphokines were ineffective in the patients' IgM synthesis. Spontaneous IgG production in patients was dramatically elevated, and the addition of lymphokines did not show any enhancing effect in patients. These results demonstrate that the IgM/IgG shift observed in peripheral blood mononuclear cell cultures also exists in purified B-cell cultures. Interleukin 2 partially restored suppressed IgM synthesis, while interleukin 4 and interferon gamma were ineffective in patients' B-cell differentiation. Interleukin 2 was the most effective lymphokine for the induction of Ig synthesis. These results lead us to conclude that the altered B-cell metabolism might also be responsible for the suppression of humoral immunity following trauma.

Depression of cellular immunity after major injury. Its association with posttraumatic complications and its reversal with immunomodulation.

This study examined a group of surgical patients with respect to the ability of their peripheral blood mononuclear cells to respond to phytohemagglutinin (PHA). Depression of the PHA response of more than 30% below baseline five to seven days after injury was found in 11 of 19 patients, and eight of them developed infectious complications. The addition of indomethacin to in vitro cultures resulted in an average enhancement of the PHA response of 37% baseline. Improvement at five to seven days with in vitro indomethacin was from 34% to 74% in infected patients. These data suggest that major injury can lead to depression of the PHA response, which correlates with the subsequent development of infectious complications. Indomethacin in vitro seems to be able to reverse or decrease this immunologic defect and deserves further study.

The immune-enhancing effect of perioperative thymopentin administration in elderly patients undergoing major surgery.

The effects of perioperative administration of thymopentin (TP-5) on in vivo and in vitro measurements of cell-mediated immunity in elderly patients undergoing major surgery were investigated. A placebo-controlled study was conducted in 25 patients (mean age, 67 years) with congenital or acquired heart disease undergoing surgery with cardiopulmonary bypass. Patients were divided into three groups: Group 1 patients were given 50 mg of TP-5 subcutaneously two hours preoperatively. Group 2 patients were given 50 mg of TP-5 subcutaneously two hours preoperatively and 48 hours postoperatively. Group 3 patients were given placebo at corresponding times. Cell-mediated immunity measurements were the in vivo delayed-type hypersensitivity (DTH) response on day 0 and on day 7 to an antigen skin test battery. The in vitro studies included antigen cocktail-induced lymphocyte proliferation of peripheral blood mononuclear cells. The DTH response on day 7 after surgery was significantly suppressed in group 3 patients compared with the preoperative baseline value, while it remained unaltered in group 1 and 2 patients. There was a considerable difference of DTH measurements (number of positive antigen responses and sum of their mean diameters) between group 2 and 3 patients. Antigen cocktail-induced lymphocyte proliferation, following initial suppression in the majority of patients, was significantly different between the placebo group and patients in group 2 on day 7 after surgery. The data indicate that perioperative administration of TP-5 might be of considerable clinical utility in preventing a defective cellular immune response.

Alteration of monocyte function following major injury.

The macrophage exerts its stimulatory and regulatory functions within the specific immune response via the interleukin 1 (IL-1) and prostaglandin E2 (PGE2), respectively. In a screening study of macrophage-related variables following injury, a total of 58 patients (mean age, 32 years; mean injury Severity Score, 38), macrophagic phenotyping with the monoclonal antibody Leu M3 and serial measuring of the antagonistic monokines IL-1 and PGE2 and of the macrophage-activating lymphokine interferon gamma were carried out on posttrauma days 0, 1, 3, 5, 7, 10, 14, and 21. The posttraumatic course was characterized by significant monocytosis, showing a peak value of 32% of Leu M3-positive cells compared with 15% of these cells in normal control subjects. During the posttrauma course, the macrophagic PGE2 output was significantly elevated up to eightfold on days 5 and 7 compared with that of control subjects (0.441 +/- 0.14 ng/mL vs 0.052 +/- 0.01 ng/mL). Conversely, macrophagic IL-1 synthesis was significantly suppressed until day 10. Levels of interferon gamma were suppressed to a significant degree during the two-day observation period, with a trend to slow recovery at the end of week 3. These data suggest that a negative regulatory macrophagic function may be the event initiating posttraumatic immunosuppression. To restore impaired macrophagic T-helper cell interaction, cyclo-oxygenase inhibition and substitution of interferon gamma may be useful to potentiate facilitatory macrophagic function and to block inhibitory macrophagic activity.

Enhanced release of elastase is not concomitant with increased secretion of granulocyte-activating cytokines in whole blood from patients with sepsis.

BACKGROUND: The proteolytic enzyme elastase released by granulocytes (polymorphonuclear leukocytes [PMN]) in high concentrations during sepsis causes degradation of essential plasma proteins, endothelial damage, and tissue edema. This may result in organ dysfunction and organ failure during sepsis, since increased elastase plasma levels correlate with the mortality rate of patients with sepsis. In vitro studies demonstrated a regulatory role of inflammatory cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin 1 beta [IL-1 beta], IL-8]) upregulating protease release by PMN. In this light, the interactions between cytokine release by macrophages and altered elastase secretion during sepsis remain to be determined. METHODS: An ex vivo model consisting of lipopolysaccharide stimulation of human whole blood as a relevant physiological milieu was used. Heparinized blood was obtained from 20 patients with sepsis syndrome (APACHE II [Acute Physiology and Chronic Health Evaluation II] score 28.5 +/- 1.2 points [mean +/- SD]) on days 0 through 3, 5, 7, and 10 after sepsis diagnosis and from 20 control patients without infection. Blood was incubated with lipopolysaccharide (1 mg/L) for 8 hours. Plasma levels of elastase, TNF-alpha, IL-1 beta, and IL-8 were determined using enzyme-linked immunosorbent assay or bioassay (TNF-alpha), respectively. RESULTS: Elastase plasma levels in whole blood from patients with sepsis were increased up to 188% (P < .01) above normal, while the release of TNF-alpha (-87%), IL-1 beta (-91%), and IL-8 (-51%) was markedly (P < .01) decreased compared with control patients. Neutralization of TNF-alpha or IL-1 beta did not attenuate the increased release of elastase. CONCLUSIONS: These data indicate an increased release of elastase by PMN despite a reduced secretion of PMN-activating cytokines. Although priming effects of TNF-alpha, IL-1 beta, and IL-8 on protease secretion in vivo cannot be excluded completely, other mediators or mechanisms may be involved in the upregulation of detrimental protease release during sepsis.

Interleukin-13 effectively down-regulates the monocyte inflammatory potential during traumatic stress.

OBJECTIVES: To determine the potential of interleukin-13 (IL-13) to modify in vitro lipopolysaccharide-induced monocyte-macrophage (MO) activity in human cells from individuals who had sustained either major mechanical or burn injury and to investigate whether the effect of IL-13 is different on MOs that have been preactivated under traumatic stress than on monocytic cells from healthy volunteers. DESIGN: Peripheral MOs from 20 controls and 16 patients after major burn or mechanical trauma were separated on days 1, 3, 5, and 7 after injury and incubated with lipopolysaccharide (1 microgram/mL) in the presence or absence of IL-13 (10 ng/mL) for 4 hours and for 20 hours. Thereafter, the following measures were determined from the culture supernatants: neopterin, nitric oxide, tumor necrosis factor alpha, IL-1 beta, IL-6, and IL-8. RESULTS: Ex vivo lipopolysaccharide-activated MOs, compared with control cells, displayed considerably enhanced inflammatory activity during the immediate posttraumatic course, with a substantial and consistent elevation of levels of tumor necrosis factor alpha and IL-6. The addition of human recombinant IL-13 to the MO cultures resulted in an effective down-regulation of the synthesis of tumor necrosis factor alpha, IL-1 beta, and IL-6 as well as IL-8, showing an average reduction of mediator production to two thirds of the value found in corresponding sole lipopolysaccharide-stimulated cultures. The impact of human recombinant IL-13 on control MOs was almost identical for IL-6 and IL-1 beta, slightly lower for IL-8, and nonexistent for tumor necrosis factor alpha. CONCLUSION: From this study and preexisting findings, we conclude that, based on its biologic properties, IL-13 should be tested as a biologic response modifier for acute states of trauma-induced host defense deficiency.

Regulation of acute phase response after cardiopulmonary bypass by immunomodulation.

The object of this prospective, randomized trial was to study the dysregulation effects of cardiopulmonary bypass on the synthesis pattern of interleukin-1, tumor necrosis factor, and interleukin-6, which have been identified as the key mediators of acute phase response. In addition, the counterregulation achieved by administration of indomethacin, which blocks the downregulating mediator prostaglandin E2, or indomethacin combined with thymopentin, which enhances T-lymphocytic reactivity, was investigated. Sixty patients who had undergone open heart operations were included in the study. These patients were divided into three groups: group A (n = 20) received both indomethacin and thymopentin, and group C (n = 20) served as control. In control patients interleukin-1 and tumor necrosis factor synthesis were suppressed postoperatively. This effect was significantly counteracted by indomethacin with no further improvement by adding thymopentin. Interleukin-6 synthesis increased in all groups. Although indomethacin treatment alone had little effect on this phenomenon, additional administration of thymopentin significantly reduced elevated interleukin-6 synthesis. Corresponding differences in clinical outcome could not be detected due to small patient numbers. This study was, however, able to demonstrate that an immunomodulatory therapy can influence alterations in immune mechanisms after cardiopulmonary bypass.