Toward a theory regarding the pathogenesis of the systemic inflammatory response syndrome: what we do and do not know about cytokine regulation

Nutritional modulation of gut inflammation

Nutritional therapy is an important component of the management of gastrointestinal inflammation, which disrupts the gut mucosal barrier leading to sepsis, SIRS and MODS. Future studies will be needed to define the role of specific nutrients in enhancing mucosal barrier function and supporting general immune function, and how this affects morbidity and mortality of critically-ill patients.

Assessment criteria in identifying the sick sepsis patient

Standard definitions of sepsis have been proposed and have been widely adopted. Recognition of the systemic inflammatory response syndrome (SIRS) and assessment of its severity can easily be achieved at the bedside using basic observations and simple laboratory tests. Fulfillment of standardized criteria defining increasing severity of sepsis or manifestation of two, three and four SIRS criteria directly correlates with risk of mortality and progression to organ failure. However, manifestation of only two SIRS criteria identifies patients who may have relatively mild disease. Furthermore, sepsis definitions take no account of pre-existing illness, source of infection or causative agent, all of which have a significant influence on outcome. Despite these limitations, manifestation of four SIRS criteria or the persistence of markers of severe sepsis identifies individuals on general wards who are at particularly high risk of death, who should be closely monitored for deterioration and discussed with an intensive-care physician at an early stage. If the source of sepsis is not clear, empirical antibiotic therapy for such individuals should be discussed with a medical microbiologist or infectious diseases physician.

Interleukin-10 reduces morbidity and mortality in murine multiple organ dysfunction syndrome (MODS)

HYPOTHESIS

IL-10 will reduce morbidity and mortality in murine MODS. Introduction. Intraperitoneal (ip) zymosan causes a triphasic inflammatory process leading to MODS. Phase I is an acute systemic inflammatory response to sterile peritonitis. Phase II is the recovery phase. Phase III is characterized by recurrent illness, progressive organ dysfunction, and elevated proinflammatory cytokines.

METHODS

Male ICR mice were randomized (on Experiment Day 0, time = 0 h) into four initial groups (A-D): Control Group A received no zymosan and no IL-10. Group B received zymosan (1 mg/g mouse BW, t = 0) and no IL-10. Group C received no zymosan and IL-10 at t = 2 h. Group D received zymosan and IL-10 at t = 2 h. On Experiment Day 4, mice in Groups B-D were randomized into six further treatment groups (B1 and B2, C1 and C2, D1 and D2). Group B1 received no treatment. Group B2 received IL-10 when clinical signs of recurrent illness developed (Phase III, 12-18 days after zymosan treatment). Mice were sacrificed when they were preterminal (clinical signs of shaking, shivering, or paralysis) or on Experiment Day 28 (survivors). Plasma total bilirubin and creatinine levels were measures of organ function. Terminal pulmonary compliance was measured in situ through a physiologic range of tidal volumes.

RESULTS

Mice entering Phase III consistently progressed to MODS characterized by elevated bilirubin and hemorrhagic lungs which, if left untreated, was lethal. Mice treated with IL-10 (Group B2) when they entered Phase III had lower mortality (28.6% vs 100%, P < 0.02), longer survival (25 vs 18 days, P < 0.05), and improved lung pulmonary compliance (slope beta1 = 0.082 ml/mm Hg vs 0.059 ml/mm Hg, P < 0.001) compared to untreated (Group B1) mice in Phase III.

CONCLUSIONS

IL-10 improves survival even when given after clinical signs of illness are present.

Posttraumatic lymphocyte response: a comparison between peripheral blood T cells and tissue T cells

BACKGROUND

T-cell response to trauma has been assessed primarily by sampling peripheral blood lymphocytes. We hypothesized that lymphocytes residing in tissue and traveling through lymph vessels are more likely to be activated by tissue injury and hemorrhage-induced hypoperfusion. We compared peripheral blood T-cell response with tissue or lymph T-cell response in an ovine model of multiple injury.

METHODS

Anesthetized adult sheep instrumented with a chronic prefemoral lymph fistula were subjected to lower-extremity fractures, fixed-volume hemorrhage, resuscitation, and fracture stabilization. Peripheral blood and tissue T-cell receptor expression was determined at baseline and after injury.

RESULTS

At baseline, we found significant differences in the expression of CD4, CD8, and L selectin between peripheral blood T cells and tissue T cells. After trauma, the percentage of tissue T cells expressing CD8 decreased from 19 +/- 9 to 14 +/- 5 (p < 0.05) and the percentage expressing gammadelta-TcR receptors decreased from 12 +/- 4 to 7 +/- 2 (p < 0.05). T-cell phenotype composition in peripheral blood was not affected by trauma.

CONCLUSION

Peripheral blood T-cell composition differs from tissue T-cell composition before and after trauma. Trauma produced changes in tissue T-cell phenotypes but not in peripheral blood T-cell phenotypes.

Catabolic proinflammatory cytokines

Catabolic proinflammatory cytokines play a key role in mediating biochemical changes associated with many pathophysiological states. The present review emphasizes the role of this type of cytokine in inflammation and cachexia. Additionally, it reviews the role of one of these mediators in the induction of insulin resistance by dealing with some of the most recent publications on this topic.

Organs from animals for man

In the following review some of the problems of xenotransplantation shall be discussed, based on the few experimental data available so far and on reports in the literature describing investigations which may be of importance for xenotransplantation. The impact of gravity on the upright posture of man versus almost all other mammals, the dysfunction between enzymes and hormones in different species and the lack of interactions between interleukins, cytokines and vasoactive substances will be taken into consideration. The question must be asked whether different levels of carrier molecules or serum proteins play a role in the physiological network. Even though the development of transgenic animals or other imaginative manipulations may lead to the acceptance of any type of xenografted organ, it has to be established for how long the products of the xenografts are able to act in the multifactorial orchestra. We are far from understanding xenogeneic molecular mechanisms involved in toxicity, necrosis and apoptosis or even reperfusion injury and ischemia in addition to the immediate mechanisms of the hyperacute xenogeneic rejection. Here, cell adhesion, blood clotting and vasomotion collide and bring micro- and macrocirculation to a standstill. All types of xenogeneic immunological mechanisms studied so far were found to have a more serious impact than those seen in allogeneic transplantation. In addition we are now only beginning to understand that so-called immunological parameters in allogeneic mechanisms act also in a true physiological manner in the xenogeneic situation. These molecular mechanisms occur behind the curtain of hyperacute, accelerated, acute or chronic xenograft rejection of which only some folds have been lifted to allow glimpses of part of the total scene. Other obstacles are likely to arise when long-term survival is achieved. These obstacles include retroviral infections, transfer of prions and severe side effects of the massive immunosuppression which will be needed. Moral, ethical and religious concerns are under debate and the species-specific production of proteins of the foreign donor species developed for clinical use suddenly appears to be a greater problem than anticipated.

Lymphocyte function in wound healing and following injury

BACKGROUND

Injury activates a cascade of local and systemic immune responses.

METHODS

A literature review was undertaken of lymphocyte function in wound healing and following injury.

RESULTS

Lymphocytes are not required for the initiation of wound healing, but an intact cellular immune response is essential for a normal outcome of tissue repair. Injury affects lymphocyte immune mechanisms leading to generalized immunosuppression which, in turn, increases host susceptibility to infection and sepsis. Although the exact origin of post-traumatic immunosuppression remains unknown, stress hormones and immunosuppressive factors, such as inflammatory cytokines, prostaglandin E2 and nitric oxide, affect lymphocyte function adversely. Post-traumatic impairment of T lymphocyte immune function is reflected in decreased lymphocyte numbers, as well as altered T cell phenotype and activity. Antibody-producing B lymphocytes are variably affected by injury, probably secondary to alterations of T lymphocyte function, as a result of their close interaction with helper T cells. Therapeutic modulation of the host immune response may include non-specific and specific interventions to improve overall defence mechanisms.

CONCLUSION

Early resuscitation to restore lymphocyte function after injury is important for tissue repair and the prevention of immunosuppression.

Systemic inflammatory response syndrome and organ dysfunction following gastrointestinal surgery

OBJECTIVES

Progression from systemic inflammatory response syndrome (SIRS) to sepsis, severe sepsis, and septic shock has been demonstrated in a variety of patients. However, the presence of SIRS alone was not helpful in predicting the development of multiple organ dysfunction syndrome (MODS) since SIRS includes many nonprogressive conditions. This study was conducted to investigate the clinical significance of SIRS in postoperative patients.

DESIGN

Retrospective study.

SETTING

The surgical department of a university hospital.

PATIENTS

Two hundred ninety-two consecutive patients who received elective common gastrointestinal surgery (esophagectomy, pancreatoduodenectomy, hepatectomy, gastrectomy, colorectal resection, and laparoscopic cholecystectomy) between 1992 and 1995.

INTERVENTIONS

Patients were analyzed for preoperative physiologic status, surgical stress parameters, and postoperative status of SIRS, complications, and end-organ dysfunction.

MEASUREMENTS AND MAIN RESULTS

Duration of SIRS or positive criteria's number of SIRS after surgery significantly correlated with surgical stress parameters (blood loss/body weight and operation time) and peak serum C-reactive protein concentrations. SIRS that continued or reappeared after postoperative day 3 was an early sign of postoperative complications. SIRS continuing consecutively for 2 days after postoperative day 3 had a 70.6% positive predictive value and a 92.5% negative predictive value for postoperative complications. Septic complications and prolongation of SIRS were associated with MODS. Five of six patients who met the SIRS criteria for >30 days developed severe MODS, and three of them died.

CONCLUSIONS

SIRS is a useful criterion for the recognition of postoperative complications and end-organ dysfunctions. Early recovery from SIRS may arrest the progression of organ dysfunction.

Participation of tissue factor and thrombin in posttraumatic systemic inflammatory syndrome

OBJECTIVE

To determine the roles of tissue factor and thrombin on the systemic inflammatory response syndrome (SIRS) in posttrauma patients, as well as to investigate the relationship between SIRS and sepsis.

DESIGN

Prospective, cohort study.

SETTING

General intensive care unit of a tertiary care emergency department.

PATIENTS

Forty trauma patients were classified into subgroups, according to the duration of SIRS: non-SIRS patients (n = 9); patients with SIRS for < 2 days (n = 15); and patients with SIRS for > 3 days (n = 16).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Tissue factor antigen concentration, prothrombin fragment F1+2, thrombin antithrombin complex, fibrinopeptide A, and cross-linked fibrin degradation products (D-dimer) were measured on the day of admission, and on days 1 through 4 after admission. Simultaneously, the number of SIRS criteria that the patients met and the disseminated intravascular coagulation score were determined. The results of these measurements, frequency of acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome, sepsis, and outcome were compared among the groups. The values of all five hemostatic molecular markers in the patients with SIRS for > 3 days were significantly more increased than those molecular marker values measured in the other groups on the day of admission. These values continued to be markedly high up to day 4 of admission. The occurrence rates of disseminated intravascular coagulation in these patient groups were significantly higher than those rates in the other two groups (p = .0001), and the disseminated intravascular coagulation scores did not improve during the study period. The occurrence rates of ARDS (p < .05) and multiple organ dysfunction syndrome (p < .01) were higher in patients with SIRS for > 3 days compared with those rates in the other groups, and the patients with SIRS for > 3 days had a poor outcome. No significant difference was noted in the frequency of sepsis among the groups.

CONCLUSIONS

Sustained SIRS is the main determinant for ARDS, multiple organ dysfunction syndrome, and outcome in posttrauma patients. Disseminated intravascular coagulation associated with massive thrombin generation and its activation is involved in the pathogenesis of sustained SIRS. Sepsis has a small role in early posttrauma multiple organ dysfunction syndrome.

Circulating endotoxin and cytokines after cardiopulmonary bypass: differential correlation with duration of bypass and systemic inflammatory response/multiple organ dysfunction syndromes

Cardiopulmonary bypass constitutes an injury that may cause postoperative pathophysiological changes due to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). These complications include coagulopathy, hypotension, capillary leakage, and multiple organ injury. To investigate the role of endotoxin and cytokines in the response to bypass injury, we measured plasma levels of endotoxin and proinflammatory cytokines in 20 pediatric patients before and after bypass. Clinical data, including duration of injury and tests indicative of SIRS/MODS, were collected. Levels of endotoxin, TNF-alpha, IL-6, and IL-8 but not IL-1 beta were significantly increased after bypass. Most of the cytokines have been found to correlate with each other. Endotoxin did not correlate with duration of bypass, cytokines, or SIRS/MODS. In contrast, TNF-alpha and IL-8 correlated with duration of bypass and were associated with SIRS/MODS. Certain clinical complications were associated with specific cytokines. Understanding the role of cytokinemia in SIRS/MODS may lead to better prognostic assessment and therapeutic modalities.

Cerebral blood flow during experimental endotoxemia in volunteers

OBJECTIVE

To measure cerebral blood flow, cerebral metabolic rate for oxygen, cerebral oxygen delivery, and cerebral vascular resistance during experimental endotoxemia in volunteers.

DESIGN

Experimental, prospective study.

SETTING

University general clinical research center.

SUBJECTS

Healthy volunteers (six male, four female, 30.1 +/- 1.9 yrs of age).

INTERVENTIONS

Volunteers had radial, pulmonary arterial, and jugular venous bulb catheters inserted. All volunteers received a bolus of Escherichia coli endotoxin (4 ng/kg). Cerebral blood flow was measured, using the Kety-Schmidt technique.

MEASUREMENTS AND MAIN RESULTS

Cerebral and systemic hemodynamics and oxygenation variables were measured at baseline and hourly for 5 hrs after endotoxin administration. A systemic hyperdynamic response characterized by an increase in body temperature (97.9 +/- 0.02, 100.2 +/- 0.02, and 99.7 +/- 0.02 degrees F [36.6 +/- 0.01, 37.9 +/- 0.1, and 37.6 +/- 0.1 degrees C] at baseline, 3, and 5 hrs, respectively), cardiac index (3.7 +/- 0.2, 6.2 +/- 0.2, and 5.7 +/- 0.2 L/min/m2 at baseline, 3, and 5 hrs), and heart rate (70 +/- 2.6, 96 +/- 2.6, and 93 +/- 2.9 beats/min at baseline, 3, and 5 hrs), and a decrease in mean arterial pressure (99.3 +/- 2.2, 84.4 +/- 2.8, and 84 +/- 3.4 mm Hg at baseline, 3, and 5 hrs) and systemic vascular resistance (1498 +/- 53, 788 +/- 37, 849 +/- 36 dyne.sec/cm5.m2 at baseline, 3, and 5 hrs) followed the endotoxin bolus. Cerebral blood flow (65.4 +/- 4.3, 57.7 +/- 3.1, and 58.6 +/- 3.0 mL/100 g/min at baseline, 3, and 5 hrs), cerebral oxygen delivery (11.6 +/- 0.7, 9.8 +/- 0.6, and 9.5 +/- 0.6 mL/100 g/min at baseline, 3, and 5 hrs), cerebral metabolic rate for oxygen (3.8 +/- 0.4, 3.3 +/- 0.3, and 3.0 +/- 0.3 mL/100 g/min at baseline, 3, and 5 hrs), and cerebral vascular resistance (1.4 +/- 0.2, 1.4 +/- 0.2, and 1.3 +/- 0.2 mm Hg/mL/100 g/min at baseline, 3, and 5 hrs) were unchanged throughout the 5-hr study period. Signs of cerebral dysfunction were not apparent, although the volunteers appeared drowsy during the latter part of the study.

CONCLUSION

A dose of endotoxin sufficient to induce systemic vasodilation in healthy subjects does not influence cerebral blood flow or the cerebral metabolic rate for oxygen.

Septic shock

Although our understanding of molecular events in septic shock is growing exponentially, bedside management has changed only incrementally over the last 20 years. In pediatric and adult patients alike, treatment continues to be largely supportive. Morbidity and mortality, though gradually improving, continue to be high. The major similarities, as well as the minor differences, between pediatric and adult septic shock are reviewed in this article, with an emphasis on current clinical practice and recent clinical investigations of novel therapies.

Systemic inflammatory response syndrome

BACKGROUND

Localized inflammation is a physiological protective response which is generally tightly controlled by the body at the site of injury. Loss of this local control or an overly activated response results in an exaggerated systemic response which is clinically identified as systemic inflammatory response syndrome (SIRS). Compensatory mechanisms are initiated in concert with SIRS and outcome (resolution, multiple organ dysfunction syndrome or death) is dependent on the balance of SIRS and such compensatory mechanisms. No directed therapies have been successful to date in influencing outcome.

METHOD

This review examines the current spectrum and pathophysiology of SIRS.

RESULTS AND CONCLUSION

Further clinical and basic scientific research is required to develop the global picture of SIRS, its associated family of syndromes and their natural histories.

Infections and the inflammatory response in acute respiratory distress syndrome

STUDY OBJECTIVE

Systemic inflammatory response syndrome (SIRS) and infections are frequently associated with the development and progression of acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome (MODS). We investigated, at onset and during the progression of ARDS, the relationships among (1) clinical variables and biological markers of SIRS, (2) infections defined by strict criteria, and (3) patient outcome. Biological markers of SIRS included serial measurements of inflammatory cytokines (IC)-tumor necrosis factor-alpha (TNF-alpha) and interleukins (IL) 1 beta, 2, 4, 6, and 8-in plasma and BAL fluid.

METHODS

We prospectively studied two groups of ARDS patients: 34 patients treated conventionally (group 1) and nine patients who received glucocorticoid rescue treatment for unresolving ARDS (group 2). Individual SIRS criteria and SIRS composite score were recorded daily for all patients. Plasma IC levels were measured by enzyme-linked immunosorbent assay on days 1, 2, 3, 5, 7, 10, and 12 of ARDS and every third day thereafter while patients received mechanical ventilation. Unless contraindicated, bilateral BAL was performed on day 1, weekly, and when ventilator-associated pneumonia was suspected. Patients were closely monitored for the development of nosocomial infections (NIs).

RESULTS

ICU mortality was similar among patients with and without sepsis on admission (54% vs 40%; p < 0.45). Among patients with sepsis-induced ARDS, mortality was higher in those who subsequently developed NIs (71% vs 18%; p < 0.05). At the onset of ARDS, plasma TNF-alpha, IL-1 beta, IL-6, and IL-8 levels were significantly higher (p < 0.0001) in nonsurvivors (NS) and in those with sepsis (p < 0.0001). The NS group, contrary to survivors (S), had persistently elevated plasma IC levels over time. In 17 patients, 36 definitive NIs (17 in group 1 and 19 in group 2) were diagnosed by strict criteria. No definitive or presumed NIs caused an increase in plasma IC levels above patients' preinfection baseline. Daily SIRS components and SIRS composite scores were similar among S and NS and among patients with and without sepsis-induced ARDS, were unaffected by the development of NI, and did not correlate with plasma IC levels.

CONCLUSIONS

Sepsis as a precipitating cause of ARDS was associated with higher plasma IC levels. However, NIs were not associated with an increase in SIRS composite scores, individual SIRS criteria, or plasma IC levels above patients' preinfection baseline. SIRS composite scores over time were similar in S and NS. SIRS criteria, including fever, were found to be nonspecific for NI. Irrespective of etiology of ARDS, plasma IC levels, but not clinical criteria, correlated with patient outcome. These findings suggest that final outcome in patients with ARDS is related to the magnitude and duration of the host inflammatory response and is independent of the precipitating cause of ARDS or the development of intercurrent NIs.

Indicators of the posttraumatic inflammatory response correlate with organ failure in patients with multiple injuries

BACKGROUND

Most prognostic indices for severely injured patients are based on anatomical findings and the vital signs. The posttraumatic organ failure, however, is thought to be triggered by the initial inflammatory response. The objective of this study was to evaluate the correlation between the early activation of inflammation and the rate of organ failure and death.

METHODS

Sixty-six patients with multiple injuries (Injury Severity Score > 18, age 18-70 years, admission within 6 hours after accident, survival > 48 hours) were included in this prospective study. During a 14-day observation period, serial blood samples were collected starting within 30 minutes after admission. Plasma levels of neutrophil elastase, lactate, antithrombin III, and interleukin-6 and -8 were determined. The clinical course and the degree of organ failure were recorded daily until death or transfer to a general ward.

RESULTS

The 66 severely injured patients had a mean Injury Severity Score of 40 points. Eleven patients died from multiple organ failure (group 1), 38 subjects survived a single or multiple organ failure (group 2), and 17 patients had an uneventful recovery (group 3). The initial plasma concentrations for neutrophil elastase (650 vs. 355 ng/mL), lactate (5.0 vs. 3.1 mmol/L), antithrombin III (48 vs. 62% from normal), interleukin-6 (703 vs. 177 pg/mL), and interleukin-8 (1,101 vs. 301 pg/mL) were significantly different between groups 2 and 3 already in the initial posttraumatic period. Patients from group 1 presented with significantly higher levels of these parameters as early as 24 hours after trauma compared with group 2. Different patterns were identified with respect to early versus late posttraumatic organ failure.

CONCLUSIONS

These data show that the degree of the initial inflammatory response corresponds with the development of posttraumatic organ failure. Besides anatomically and physiologically based trauma scores, these parameters might be used as indicators for the injury severity.

Whole gut washout for severe sepsis: review of technique and preliminary results

BACKGROUND

The purpose of this study was to determine the safety and feasibility of whole gut washout for severe sepsis in human beings.

METHODS

High-volume polyethylene glycol-3500 was administered to patients with severe sepsis. Body temperature, white blood cell count, and ventilatory indexes were recorded 24 hours before and 24 hours after whole gut washout.

RESULTS

A significant decrease in febrile response was observed after gut washout with polyethylene glycol. Improvements in PaO2, positive end-expiratory pressure, and peak airway pressure were observed. The washout was well tolerated in all but one patient.

CONCLUSIONS

High-volume whole gut washout for severe sepsis appears safe in critically ill patients and may offer some promise in reducing enterogenic inflammation after catabolic stress.

Oral endotoxin in healthy adults

This article presents a study that measured oral endotoxin levels in healthy persons with the Limulus amoebocyte lysate microassay. Only young nonsmoking adults with a healthy dentition measured with the plaque index and a good level of oral hygiene based on a twice-daily (morning and evening) tooth-brushing regimen were admitted to this open study. Each person was required to provide two oral washings of 10 ml sterile saline solution 1 week apart. Only those volunteers without oral carriage of aerobic gram-negative bacilli were enrolled in the baseline study. A total of 15 healthy adults with a median age of 29 years (range, 25 to 43 years) were included in the trial. The mean plaque score of the group was 1.2 +/- 0.1. They all maintained a twice-daily tooth-brushing regimen unaltered throughout the sampling period. A total of 30 mouth rinses were studied. None of the samples yielded potential pathogens including aerobic gram-negative bacilli, Staphylococcus aureus and yeasts; a culturing technique based on preenrichment in nutrient medium was used. Data showed mean oral endotoxin levels of 20 ng per ml of mouth rinse; the aerobic E. coli endotoxin was used as the classical standard. This is equivalent to 1 mg of anaerobic endotoxin per ml of undiluted saliva after correcting for the 10 to 10(2) dilution factor of the mouth rinse itself and for the 10(3) times less sensitivity of anaerobic endotoxin in the Limulus amoebocyte lysate-assay. The discussion includes the physiologic and clinical benefit of the low endotoxicity of anaerobic gram-negative flora apart from the technical aspects of both culture and endotoxin assays used in the study.

INTERSEPT: an international, multicenter, placebo-controlled trial of monoclonal antibody to human tumor necrosis factor-alpha in patients with sepsis. International Sepsis Trial Study Group

OBJECTIVE

To determine the safety and efficacy of BAY x 1351, a murine monoclonal antibody to recombinant human tumor necrosis factor (TNF)-alpha, in patients with sepsis.

DESIGN

An international, multicenter, prospective, placebo-controlled trial in patients with sepsis, stratified into shock/nonshock groups.

SETTING

Forty acute clinical care facilities in 14 countries.

PATIENTS

Of the 564 patients enrolled in the study, 553 patients received study drug or placebo.

INTERVENTIONS

Patients received 15 mg/kg or 3 mg/kg of BAY x 1351, or placebo, as a single intravenous infusion.

MEASUREMENTS AND MAIN RESULTS

The patients were well matched for severity of illness and for risk factors known to influence the outcome of sepsis. There was no difference in 28-day mortality rates between groups (placebo group 66 [39.5%] of 167;3 mg/kg group 57 [31.5%] of 181; 15 mg/kg group 87 [42.4%] of 205). Approximately 9 months after this study had begun, an interim safety examination of NORASEPT, a North American Sepsis Trial using the same monoclonal antibody, indicated that there was no benefit to patients in the nonshock group and further enrollment of these nonshock septic patients into INTERSEPT was stopped. The analysis therefore focused on the 420 patients in shock. The primary efficacy variable was the 28-day, all-cause mortality rate: placebo group 57 (42.9%) of 133; 3-mg/kg group 51 (36.7%) of 139; and 15-mg/kg group 66 (44.6%) of 148 (not significant). Two secondary efficacy variables were identified prospectively: shock reversal and frequency of organ failures. Life-table analysis showed that in patients who survived 28 days, there was a more rapid reversal of shock in both treatment groups compared with placebo (15-mg/kg group vs. placebo group log-rank statistic p = .007, 3-mg/kg group vs. placebo group p = .01). Similarly, in patients surviving 28 days, there was a significant delay in the time to the onset of first organ failure (log rank 15 mg/kg vs. placebo p = .03, 3 mg/kg vs. placebo p = .07), and more patients in the placebo group developed at least one organ failure: 15-mg/kg group 33 (40.2%) of 82; 3-mg/kg group 39 (44.3%) of 88; and placebo group 45 (59.2%) of 76 (15 mg/kg vs. placebo p = .03, 3 mg/kg vs. placebo p = .06). No significant adverse events were associated with the monoclonal antibody treatment.

CONCLUSIONS

INTERSEPT provides additional clinical data implicating TNF-alpha as an integral mediator of septic shock. The study suggested a possible role for anti-TNF antibody as adjunctive therapy, but this possibility requires confirmation by another clinical trial.