Towards precision medicine in sepsis: a position paper from the European Society of Clinical Microbiology and Infectious Diseases

BACKGROUND

Our current understanding of the pathophysiology and management of sepsis is associated with a lack of progress in clinical trials, which partly reflects insufficient appreciation of the heterogeneity of this syndrome. Consequently, more patient-specific approaches to treatment should be explored.

AIMS

To summarize the current evidence on precision medicine in sepsis, with an emphasis on translation from theory to clinical practice. A secondary objective is to develop a framework enclosing recommendations on management and priorities for further research.

SOURCES

A global search strategy was performed in the MEDLINE database through the PubMed search engine (last search December 2017). No restrictions of study design, time, or language were imposed.

CONTENT

The focus of this Position Paper is on the interplay between therapies, pathogens, and the host. Regarding the pathogen, microbiologic diagnostic approaches (such as blood cultures (BCs) and rapid diagnostic tests (RDTs)) are discussed, as well as targeted antibiotic treatment. Other topics include the disruption of host immune system and the use of biomarkers in sepsis management, patient stratification, and future clinical trial design. Lastly, personalized antibiotic treatment and stewardship are addressed (Fig. 1).

IMPLICATIONS

A road map provides recommendations and future perspectives. RDTs and identifying drug-response phenotypes are clear challenges. The next step will be the implementation of precision medicine to sepsis management, based on theranostic methodology. This highly individualized approach will be essential for the design of novel clinical trials and improvement of care pathways.

Endothelial barrier dysfunction in septic shock

The endothelium provides an essential and selective membrane barrier that regulates the movement of water, solutes, gases, macromolecules and the cellular elements of the blood from the tissue compartment in health and disease. Its structure and continuous function is essential for life for all vertebrate organisms. Recent evidence indicates that the endothelial surface does not have a passive role in systemic inflammatory states such as septic shock. In fact, endothelial cells are in dynamic equilibrium with a myriad of inflammatory mediators and elements of the innate immune and coagulation systems to orchestrate the host response in sepsis. The barrier function of the endothelial surface is almost uniformly impaired in septic shock, and it is likely that this contributes to adverse outcomes. In this review, we will highlight recent advances in the understanding of the signalling events that regulate endothelial function and molecular events that induce endothelial dysfunction in sepsis. Endothelial barrier repair strategies as a treatment for sepsis include modulation of C5a, high-mobility group box 1 and VEGF receptor 2; stimulation of angiopoietin-1, sphingosine 1 phosphate receptor 1 and Slit; and a number of other innovative approaches.

Treatment effects of high-dose antithrombin without concomitant heparin in patients with severe sepsis with or without disseminated intravascular coagulation

BACKGROUND

Disseminated intravascular coagulation (DIC) is a serious complication of sepsis that is associated with a high mortality.

OBJECTIVES

Using the adapted International Society on Thrombosis and Haemostasis (ISTH) diagnostic scoring algorithm for DIC, we evaluated the treatment effects of high-dose antithrombin (AT) in patients with severe sepsis with or without DIC.

PATIENTS AND METHODS

From the phase III clinical trial in severe sepsis (KyberSept), 563 patients were identified (placebo, 277; AT, 286) who did not receive concomitant heparin and had sufficient data for DIC determination.

RESULTS

At baseline, 40.7% of patients (229 of 563) had DIC. DIC in the placebo-treated patients was associated with an excess risk of mortality (28-day mortality: 40.0% vs. 22.2%, P < 0.01). AT-treated patients with DIC had an absolute reduction in 28-day mortality of 14.6% compared with placebo (P = 0.02) whereas in patients without DIC no effect on 28-day mortality was seen (0.1% reduction in mortality; P = 1.0). Bleeding complications in AT-treated patients with and without DIC were higher compared with placebo (major bleeding rates: 7.0% vs. 5.2% for patients with DIC, P = 0.6; 9.8% vs. 3.1% for patients without DIC, P = 0.02).

CONCLUSIONS

High-dose AT without concomitant heparin in septic patients with DIC may result in a significant mortality reduction. The adapted ISTH DIC score may identify patients with severe sepsis who potentially benefit from high-dose AT treatment.

Caring for the critically ill patient. High-dose antithrombin III in severe sepsis: a randomized controlled trial

CONTEXT

Activation of the coagulation system and depletion of endogenous anticoagulants are frequently found in patients with severe sepsis and septic shock. Diffuse microthrombus formation may induce organ dysfunction and lead to excess mortality in septic shock. Antithrombin III may provide protection from multiorgan failure and improve survival in severely ill patients.

OBJECTIVE

To determine if high-dose antithrombin III (administered within 6 hours of onset) would provide a survival advantage in patients with severe sepsis and septic shock.

DESIGN AND SETTING

Double-blind, placebo-controlled, multicenter phase 3 clinical trial in patients with severe sepsis (the KyberSept Trial) was conducted from March 1997 through January 2000.

PATIENTS

A total of 2314 adult patients were randomized into 2 equal groups of 1157 to receive either intravenous antithrombin III (30 000 IU in total over 4 days) or a placebo (1% human albumin).

MAIN OUTCOME MEASURE

All-cause mortality 28 days after initiation of study medication.

RESULTS

Overall mortality at 28 days in the antithrombin III treatment group was 38.9% vs 38.7% in the placebo group (P =.94). Secondary end points, including mortality at 56 and 90 days and survival time in the intensive care unit, did not differ between the antithrombin III and placebo groups. In the subgroup of patients who did not receive concomitant heparin during the 4-day treatment phase (n = 698), the 28-day mortality was nonsignificantly lower in the antithrombin III group (37.8%) than in the placebo group (43.6%) (P =.08). This trend became significant after 90 days (n = 686; 44.9% for antithrombin III group vs 52.5% for placebo group; P =.03). In patients receiving antithrombin III and concomitant heparin, a significantly increased bleeding incidence was observed (23.8% for antithrombin III group vs 13.5% for placebo group; P<.001).

CONCLUSIONS

High-dose antithrombin III therapy had no effect on 28-day all-cause mortality in adult patients with severe sepsis and septic shock when administered within 6 hours after the onset. High-dose antithrombin III was associated with an increased risk of hemorrhage when administered with heparin. There was some evidence to suggest a treatment benefit of antithrombin III in the subgroup of patients not receiving concomitant heparin.

Lipopolyamines as a therapeutic strategy in experimental Gram-negative bacterial sepsis

Lipopolyamines are a class of polycationic amphiphilic compounds that have been shown to bind with high affinity to polyanionic macromolecules, including both DNA and bacterial lipopoly-saccharide (LPS). One of these compounds, termed DOSPER (1,3-di-oleoyloxy-2-(6-carboxyl-spermyl)- propylamide), is non-cytotoxic and has been shown to inhibit LPS-mediated cytokine release and lethality in endotoxin challenge models. In the study reported here, the activity of DOSPER was tested in neutropenic rats with invasive Gram-negative bacteremia caused by Pseudomonas aeruginosa. DOSPER alone was ineffective (0/8) at influencing mortality, but provided a significant survival advantage if administered in combination with a bactericidal antibiotic, ceftazidime (10/12; P<0.05). Ceftazidime alone was partially protective (6/12) while the control group had no survivors (0/8). DOSPER administration markedly reduced circulating endotoxin levels (P<0.01) and interleukin-6 levels (P<0.05) but had no significant effect on bacteremia and bacterial concentrations of P. aeruginosa in liver or spleen tissue. Lipopolyamines may be potentially valuable as a therapeutic adjunct in treatment of Gram-negative bacterial sepsis.

Clinical impact of novel anticoagulation strategies in sepsis

Derangements in coagulation and fibrinolysis are frequent complications of systemic infection, and septic shock is the most common recognized cause of disseminated intravascular coagulation. Anticoagulant therapy has been used as a treatment strategy for severe sepsis for several decades without compelling evidence of efficacy until the 2001 publication of the phase III trial with recombinant human activated protein C. Major phase III international trials with antithrombin and tissue factor pathway inhibitor also have been completed recently. The molecular mechanisms by which the clotting system interacts with the innate immune response have greatly facilitated the understanding of coagulation and the pathophysiology of septic shock. Anticoagulants such as recombinant human activated protein C and related agents may become the mainstay of adjuvant therapies for severe sepsis in the near future.

Release of urokinase plasminogen activator receptor during urosepsis and endotoxemia

BACKGROUND

The urokinase receptor (uPAR; CD87) is a multifunctional molecule involved in fibrinolysis, in proteolysis, in renal tubular functions, and in migration and adhesion of inflammatory cells to the site of infection.

METHODS

To gain insight into systemic and local release of uPAR and into its regulation during urosepsis, which is one of the leading causes of chronic renal failure, uPAR was measured in urine and plasma of healthy human controls (N = 20), patients with culture-proven urosepsis (N = 30), and healthy human volunteers intravenously injected with endotoxin (N = 7).

RESULTS

Patients had elevated uPAR levels in both plasma and urine. Three hours after endotoxin challenge in volunteers, there was also a significant increase of uPAR in plasma and in urine. The urine/plasma ratio for uPAR was highly elevated during urosepsis and experimental endotoxemia, suggesting local production in the kidney. Accordingly, damaged tubuli strongly expressed uPAR during pyelonephritis. Moreover, tubular epithelial cells produced uPAR in vitro, and this secretion was strongly up-regulated after stimulation with interleukin-1 beta or tumor necrosis factor-alpha.

CONCLUSIONS

We found that uPAR is released systemically and in the urinary tract during urosepsis and experimental endotoxemia. This systemic and renal production of uPAR during pyelonephritis may play a central role in eliminating the infection and protecting renal function.

Evaluation of the safety of recombinant P-selectin glycoprotein ligand-immunoglobulin G fusion protein in experimental models of localized and systemic infection

P-selectin is a major component in the early interaction between platelets, endothelial cells, and inflammatory cells in the initial phases of the innate immune response. The major ligand for P-selectin is P-selectin glycoprotein ligand-1 (PSGL-1) and this ligand is expressed on the surface of monocyte, lymphocyte, and neutrophil membranes. A truncated form of recombinant human P-selectin glycoprotein ligand-1 has been covalently linked to immunoglobulin G (rPSGL-Ig) and this fusion peptide functions as a competitive inhibitor of PSGL-1. As an inhibitor of neutrophil-endothelial cell adherence, rPSGL-Ig is in early clinical development for the treatment of ischemia reperfusion injury. To determine the potential for deleterious effects from inhibition in P-selectin-mediated neutrophil attachment in the presence of bacterial infection, the effects of therapeutic doses of rPSGL-Ig were tested in three standard laboratory sepsis models. The experimental models included: the murine systemic Listeria monocytogenes infection model, the Pseudomonas aeruginosa bacteremia model in neutropenic rats, and the cecal ligation and puncture (CLP)-induced peritonitis model in rats. Recombinant human PSGL-Ig had no adverse effects on mortality or immune clearance in systemic bacterial infection in any of the three infection models. The PSGL-1 inhibitor did significantly decrease local neutrophil infiltration and bacterial clearance in the peritoneum following CLP, but this did not increase the systemic levels of proinflammatory cytokines, the quantitative levels of bacteremia, or the overall mortality rate following CLP. The results indicate that rPSGL-Ig did not exacerbate infection in these experimental sepsis models.

Active immunization with a detoxified Escherichia coli J5 lipopolysaccharide group B meningococcal outer membrane protein complex vaccine protects animals from experimental sepsis

The passive infusion of antibodies elicited in rabbits with a detoxified J5 lipopolysaccharide (LPS)/group B meningococcal outer membrane protein complex vaccine protected neutropenic rats from heterologous lethal gram-negative bacterial infection. In this study, active immunization was studied in neutropenic rats infected with Pseudomonas aeruginosa, in the presence or absence of ceftazidime therapy, and with Klebsiella pneumoniae. This vaccine elicited a > 200-fold increase in anti-J5 LPS antibody, which remained elevated throughout the duration of cyclophosphamide-induced neutropenia and for < or = 3 months. There was improved survival among immunized versus control animals: 48% (13/28) versus 7% (2/29) in Pseudomonas-challenged rats; 61% (11/18) versus 0% (0/10) in Pseudomonas- and ceftazidime-treated rats; and 64% (9/14) versus 13% (2/15) in Klebsiella-challenged rats (P < 0.01 for each comparison). Immunized animals had lower levels of bacteria in organs and lower levels of circulating endotoxin at the onset of fever. In conclusion, active immunization with an anti-endotoxin vaccine improved survival after infection with > or = 2 heterologous, clinically relevant bacterial species in immunocompromised animals. Active immunization with this vaccine merits further investigation.

The activity of tissue factor pathway inhibitor in experimental models of superantigen-induced shock and polymicrobial intra-abdominal sepsis

OBJECTIVES

To study recombinant human tissue factor pathway inhibitor (rhTFPI) in a superantigen-induced shock model and in a cecal ligation and puncture (CLP) model of peritonitis in mice.

DESIGN

Prospective, randomized, experimental study.

SETTING

An experimental animal research laboratory.

SUBJECTS

Eighty BALB/c mice for the superantigen model, and 56 BALB/c mice for the CLP model.

INTERVENTIONS

In the superantigen-induced shock model, animals received rhTFPI (350 mg/kg) subcutaneously every 12 hrs (n = 30) or saline control (n = 30) for 60 hrs after staphylococcal enterotoxin B (SEB; 10 microg iv) and a sublethal dose of E. coli 0111:B4 lipopolysaccharide (LPS; 75 microg ip). Control groups received SEB alone (n = 10) and LPS alone (n = 10). In the CLP model, rhTFPI or saline was given every 8 hrs for 48 hrs by using a 21-gauge needle (n = 9) or 23-gauge needle (n = 14) for CLP. A sham surgery control group (n = 10) was also included.

MEASUREMENTS AND MAIN RESULTS

There was 0% mortality in the SEB and LPS control groups. The mortality rate was 64% in the saline control group that received both SEB and LPS (19 of 30), whereas the rhTFPI- treated animals had a mortality rate of 20% (6 of 30; p < .01). The rhTFPI-treated group had significantly lower interleukin-6 levels (61.8 +/- 41 pg/mL vs. 285 +/- 63 pg/mL; p < .05) than the control group but no differences in tumor necrosis factor-alpha or interferon-gamma levels. In the CLP experiment, rhTFPI-treated animals did not have any survival advantage over the control group after the large-bore (21-gauge) needle puncture. The rhTFPI group had significantly improved 7-day mortality rate after CLP with the small-bore needle (23-gauge; 21.4% [rhTFPI] vs. 71.4% [control], p < .01). Plasma LPS, interleukin-6, interferon-gamma, and tumor necrosis factor-alpha levels were unchanged by rhTFPI treatment, but significantly reduced LPS (p = .006) and IFNgamma (p = .001) levels were found in the peritoneal fluid.

CONCLUSIONS

Tissue factor pathway inhibitor significantly improves the mortality rate in models of superantigen-induced shock and polymicrobial intra-abdominal infection, supporting its potential use in clinical trials for septic shock.

Chemotactic activity of CXC chemokines interleukin-8, growth-related oncogene-alpha, and epithelial cell-derived neutrophil-activating protein-78 in urine of patients with urosepsis

CXC chemokines are chemotactic cytokines that specifically act on neutrophils. To obtain insight into the extent of local production of CXC chemokines during acute pyelonephritis, interleukin (IL)-8, growth-related oncogene (GRO)-alpha, and epithelial cell-derived neutrophil-activating protein (ENA)-78 were measured in urine and plasma samples from patients with culture-proven urosepsis (n=33), healthy human control subjects with sterile urine (n=31), and human volunteers intravenously injected with endotoxin (n=11). Patients had profoundly elevated urine concentrations of chemokines with no (GRO-alpha and ENA-78) or little (IL-8) elevation in plasma. Endotoxin-challenged subjects demonstrated transient increases in plasma chemokine concentrations, with no (GRO-alpha) or little (IL-8 and ENA-78) elevation in urine. Urine from patients exerted chemotactic activity toward neutrophils, which was partially inhibited by neutralizing antibodies against IL-8, GRO-alpha, or ENA-78. During urosepsis, CXC chemokines are predominantly produced within the urinary tract, where they are involved in the recruitment of neutrophils to the urinary compartment.

What are the microbial components implicated in the pathogenesis of sepsis? Report on a symposium

Despite considerable efforts in the past quarter century to improve therapy for sepsis, mortality rates remain unacceptably high. Microbe-derived constituents can induce the host to produce many mediators that can contribute to immune dysregulation, tissue damage, and death. Although endotoxin-mediated events are clearly important in gram-negative infections, gram-positive bacteria can also play a dominant role. Understanding the interplay of microbial constituents and host immune or inflammatory responses prompted a meeting at Rockefeller University in May 1998. Participants discussed the relative merits of a "2-hit" hypothesis to explain the course of lethal septic shock and a "multihit" synergistic threshold hypothesis. Recommendations include the following: (1) developing animal models that closely mimic human sepsis; (2) further investigating antibiotic effects on bacteria; (3) assessing the relationships between endotoxin, prokaryotic DNA, and peptidoglycan (i.e., independent, additive, or synergistic) in inducing host responses; and (4) developing new strategies to improve outcomes. Studies are needed to better define which and how different microbial constituents lead to sepsis and to provide critical leads for therapeutic intervention.

Therapeutic rationale for antithrombin III in sepsis

OBJECTIVE

To review the preclinical evidence that provides the therapeutic rationale for antithrombin as a novel treatment for human sepsis.

DATA SOURCES

A summary of published medical literature from MEDLINE search files and other reviews published about antithrombin use in sepsis.

DATA SUMMARY

Antithrombin has a variety of antiinflammatory properties in addition to its functions as an endogenous anticoagulant that appear to have an important therapeutic role in the prevention of microvascular dysfunction and multiple organ injury in sepsis. Appropriate timing and dosing of antithrombin III is critical to realize its full therapeutic potential as an anti-sepsis therapy.

CONCLUSIONS

Antithrombin is a potent inhibitor of thrombin-mediated vascular injury in the microcirculation in severe sepsis. This endogenous anticoagulant is rapidly depleted in the early phases of sepsis as a result of decreased synthesis, increased destruction, and enhanced clearance by thrombin-antithrombin complex formation. The therapeutic efficacy of antithrombin in experimental sepsis is readily demonstrable in numerous animal systems. Appropriately defined patient populations with early onset severe sepsis and/or septic shock may benefit from antithrombin therapy if it is administered in adequate doses at the optimal time interval.

Phylogenetic and functional relationships between coagulation and the innate immune response

Activation of the coagulation system frequently accompanies systemic inflammatory states and is an almost invariable consequence of septic shock. The simultaneous activation of the innate immune response and the coagulation system after injury is a phylogenetically ancient, adaptive response that can be traced back to the early stages of eukaryotic evolution. Most invertebrate species lack differentiated phagocytic cells and platelets. They possess a common cellular and humoral pathway of inflammation and clotting after a breach in their internal milieu by either trauma or infection. The close linkage between clotting and inflammation has been preserved throughout vertebrate evolution and is readily demonstrable in human physiologic responses to a variety of potentially injurious stimuli. The same proinflammatory stimuli that activate the human clotting cascade also activate the phagocytic effector cells (neutrophils, monocytes, and macrophages). The complex and highly integrated linkage between systemic inflammation and coagulation are reviewed in this article.

Anti-inflammatory cytokines

The anti-inflammatory cytokines are a series of immunoregulatory molecules that control the proinflammatory cytokine response. Cytokines act in concert with specific cytokine inhibitors and soluble cytokine receptors to regulate the human immune response. Their physiologic role in inflammation and pathologic role in systemic inflammatory states are increasingly recognized. Major anti-inflammatory cytokines include interleukin (IL)-1 receptor antagonist, IL-4, IL-6, IL-10, IL-11, and IL-13. Specific cytokine receptors for IL-1, tumor necrosis factor-alpha, and IL-18 also function as proinflammatory cytokine inhibitors. The nature of anti-inflammatory cytokines and soluble cytokine receptors is the focus of this review. The current and future therapeutic uses of these anti-inflammatory cytokines are also reviewed.

Differential antibiotic-induced endotoxin release in severe melioidosis

Severe melioidosis is a life-threatening, systemic bacterial infection caused by Burkholderia pseudomallei. A prospective, randomized treatment trial was conducted in northeast Thailand to compare ceftazidime (a penicillin-binding protein [PBP]-3-specific agent that causes release of large amounts of endotoxin in vitro) and imipenem (a PBP-2-specific agent that kills B. pseudomallei more rapidly but releases low amounts of endotoxin) in severe melioidosis over a 6-h time course after the first dose of antibiotic. Despite similar clinical, microbiological, endotoxin, and cytokine measures at study entry, ceftazidime-treated patients (n=34) had significantly greater systemic endotoxin (P<.001) than patients treated with imipenem (n=34) after the first dose of antibiotic. No overall difference in mortality was observed (35% in both groups [95% confidence interval, 20%-50%]). Differential antibiotic-induced endotoxin release is demonstrable in severe melioidosis. These differences in endotoxin release did not appear to have a significant impact on survival in this group of patients.

Recombinant human interleukin-11 has anti-inflammatory actions yet does not exacerbate systemic Listeria infection

To determine whether recombinant human (rh) interleukin (IL)-11 disrupts the clearance of microbial pathogens, mice were challenged with Listeria monocytogenes after receiving high-dose rhIL-11, anti-tumor necrosis factor (TNF) monoclonal antibody (MAb), anti-IL-11 MAb, or saline control. The LD50 was not affected by rhIL-11 but was 10-fold lower in the anti-TNF MAb group (P<.001). Plasma IL-6, IL-1beta, and TNF-alpha levels were not different between rhIL-11-treated animals and the control group; however, interferon-gamma levels were significantly reduced by IL-11 treatment (2477 vs. 0 pg/mL, P<.01). Compared with the control group, the quantitative level of L. monocytogenes in hepatic and splenic tissue was unchanged by rhIL-11 but was significantly increased by TNF or IL-11 inhibition. The results indicate that IL-11 down-regulates cytokine production but does not exacerbate systemic infection in the murine Listeria infection model.

Consensus conference definitions for sepsis, septic shock, acute lung injury, and acute respiratory distress syndrome: time for a reevaluation

Definitions for sepsis, septic shock, acute lung injury (ALI), and acute respiratory distress syndrome (ARDS) were developed by consensus conferences with the goal of achieving standardization of terminology and improved homogeneity of patient populations in clinical studies. Although such definitions have been useful in epidemiologic investigations, the criteria specified by the consensus conferences are broad and insufficiently specific to address the problem of heterogeneous mechanisms leading to clinical syndromes. An important challenge is to progress from clinical syndromes, as presently defined, to more specific entities that are delineated by alterations in specific immunologic or biochemical pathways. Such mechanistic definitions will provide more homogeneous groups of patients who can be identified at early stages of their clinical course. This approach encourages focused investigation of pathways leading to organ system dysfunction and death and, also, provides an efficient framework for the development of new therapies useful in critically ill patients.

Relationship between plasma levels of lipopolysaccharide (LPS) and LPS-binding protein in patients with severe sepsis and septic shock

Plasma endotoxin and lipopolysaccharide-binding protein (LBP) levels were measured in a group of 253 patients at the onset of severe sepsis and/or septic shock. Endotoxin levels were significantly greater than control levels (n=33; mean +/- SD, 5.1+/-7.3 pg/mL) in 78.3% of patients. Median endotoxin levels in patients with sepsis were 300 pg/mL (25%-75% interquartile range, 110-726 pg/mL). LBP levels were elevated in 97% of patients compared with normal control values of 4.1+/-1.65 microgram/mL. Median LBP levels in patients with sepsis were 31.2 microgram/mL (interquartile range, 22.5-47.7 microgram/mL). Median endotoxin levels at study entry were more highly elevated (515 vs. 230 pg/mL; P<.01), and LBP levels were less highly elevated (28.0 vs. 33.2 microgram/mL; P<.05) in nonsurvivors than survivors over the 28-day study period. No correlation was found between endotoxin and LBP levels. The quantitative level of both endotoxin and LBP may have prognostic significance in patients with severe sepsis.

Immunotherapy of sepsis: flawed concept or faulty implementation?

Gram-negative bacillary sepsis is a leading cause of death among patients hospitalized in intensive care units. While initial clinical studies with the passive administration of anti-endotoxin core-glycolipid (CGL) antibodies for the treatment and prophylaxis of sepsis showed promising results, subsequent studies failed to show a consistent benefit. There appears to be a good correlation between anti-CGL antibody levels at the onset of sepsis and maintenance of antibody levels during sepsis with outcome. Previous clinical studies may have failed because insufficient amounts of antibody were administered early in the course of sepsis. Unlike the case with anti-CGL antibodies, polyvalent, hyperimmune type-specific antibody preparations may prevent the development of infections; however, these antibodies also must be provided in adequate amounts and in close proximity to infection in order to provide a beneficial effect. These pharmacokinetic requirements may limit the utility of passive immunotherapy for the prophylaxis of sepsis. Active immunization of acutely traumatized patients or of rats subsequently rendered neutropenic with cyclophosphamide induced high antibody levels for extended periods of time. Since trauma and other conditions are associated with a Th(2) response, these conditions may favor antibody formation following active immunization. Active immunization with both anti-CGL and/or polyvalent-specific vaccines for the prophylaxis of sepsis with passive supplementation at the onset of sepsis is an approach that merits further investigation.

Clinical gram-positive sepsis: does it fundamentally differ from gram-negative bacterial sepsis?

OBJECTIVE

To review the basic differences between gram-positive and gram-negative sepsis and to assess the effect of these differences on current and future therapeutic strategies for sepsis.

DESIGN

Literature review of the past 30 yrs of laboratory and clinical reports that analyze the microbial aspects of sepsis and the immunologic response to systemic infection.

RESULTS

The increasing prevalence of sepsis from gram-positive bacterial pathogens necessitates reevaluation of many of the basic assumptions about the molecular pathogenesis of septic shock. It has been assumed that the initiation of the systemic inflammatory response with activation of the proinflammatory cytokine networks and other mediators results in a similar pathophysiologic process, regardless of the causative microbic pathogen. Yet, there is increasing experimental evidence that fundamental differences exist in the host response to gram-positive bacterial pathogens compared with the host response to gram-negative organisms. Systemic immune activation during sepsis may promote the clearance of the microbic pathogen; however, generalized inflammation also contributes to the pathogenesis of septic shock. The balance between these beneficial and deleterious effects may differ between gram-positive and gram-negative pathogens.

CONCLUSIONS

Results of antimediator therapies in clinical trials in septic shock are inconclusive but suggest that the response may differ, depending on the type of microbic pathogen. The immune-mediated pathophysiologic mechanisms that underlie gram-positive sepsis and the potential interactions between the infecting microorganism and efficacy of anticytokine therapies require further investigation. Treatment strategies that explain the causative organism may be necessary for optimal use of immunoadjuvants in the future.

Clinical trials for severe sepsis. Past failures, and future hopes

Recent clinical trials with experimental immunotherapeutic agents for severe sepsis and septic shock have been largely unsuccessful despite seemingly convincing preclinical evidence of significant benefit of these antisepsis therapies. This article reviews basic therapeutic rationale, preclinical evaluation, and clinical trial design of past clinical trials of innovative sepsis treatments. Lessons learned from past failures should provide insights into the design and implementation of successful clinical trials for new anti-sepsis agents in the future.

Additive effects of human recombinant interleukin-11 and granulocyte colony-stimulating factor in experimental gram-negative sepsis

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is widely used to promote granulocyte recovery from a variety of pathologic states. Recombinant human interleukin-11 (rhIL-11) has recently become available clinically as a platelet restorative agent after myelosuppressive chemotherapy. Preclinical data has shown that rhIL-11 limits mucosal injury after chemotherapy and attenuates the proinflammatory cytokine response. The potential efficacy of combination therapy with recombinant human forms of rhIL-11 and rhG-CSF was studied in a neutropenic rat model of Pseudomonas aeruginosa sepsis. At the onset of neutropenia, animals were randomly assigned to receive either rhG-CSF at a dose of 200 micrograms/kg subcutaneously every 24 hours for 7 days; rhIL-11 at 200 micrograms/kg subcutaneously every 24 hours for 7 days; the combination of both rhG-CSF and rhIL-11; or saline control. Animals were orally colonized with Pseudomonas aeruginosa 12.4.4 and then given a myelosuppressive dose of cyclophosphamide. rhG-CSF resulted in a slight increase in absolute neutrophil counts (ANC), but did not provide a survival advantage (0 of 12, 0% survival) compared with the placebo group (1 of 12, 8% survival). rhIL-11 was partially protective (4 of 10, 40% survival); the combination of rhG-CSF and rhIL-11 resulted in a survival rate of 80% (16 of 20; P <.001). rhIL-11 alone or in combination with rhG-CSF resulted in preservation of gastrointestinal mucosal integrity (P <.001), lower circulating endotoxin levels (P <.01), and reduced quantitative levels of P. aeruginosa in quantitative organ cultures. These results indicate that the combination of rhIL-11 and rhG-CSF is additive as a treatment strategy in the prevention and treatment of experimental Gram-negative sepsis in immunocompromised animals. This combination may prove to be efficacious in the prevention of severe sepsis in neutropenic patients.

Interleukin-10: potential benefits and possible risks in clinical infectious diseases

Human interleukin-10 (IL-10) is a potent anti-inflammatory cytokine that inhibits the synthesis of the major proinflammatory cytokines and chemokines. IL-10 is the principal TH2-type cytokine that upregulates humoral immune responses and attenuates cell-mediated immune reactions. This cytokine has a number of immunomodulatory properties that might be clinically useful in a variety of inflammatory and infectious disease states. Clinical trials with human recombinant IL-10 are already in progress. Carefully selected patients with inflammatory conditions may benefit from IL-10 therapy if concomitant infectious diseases are recognized and treated appropriately.

Recombinant human interleukin-11 in experimental Pseudomonas aeruginosa sepsis in immunocompromised animals

The therapeutic potential of recombinant human interleukin-11 (rhIL-11) was tested in a neutropenic rat model that mimics the clinical consequences of myelosuppressive chemotherapy complicated by Pseudomonas aeruginosa sepsis. rhIL-11-treated animals (150 micrograms/kg intravenously every 24 h for 3 days) had reduced endotoxin levels (P < .05) and less pulmonary edema fluid (P < .001) and were protected (P < .01) against thinning and necrosis of the intestinal mucosa compared with the control group. The survival rate in rhIL-11-treated animals was 40% (19/47), whereas it was 0 (0 of 19) in the control group (P < .01). The addition of ciprofloxacin (10 mg/kg every 12 h) resulted in a survival rate of 9 (60%) of 15, while the combination of rhIL-11 and ciprofloxacin resulted in 100% survival (15/15; P < .05). These results indicate that rhIL-11 supports mucous membrane integrity of the alimentary tract and decreases the systemic inflammatory response to experimental gram-negative infection in immunocompromised animals.

Why have group A streptococci remained susceptible to penicillin? Report on a symposium

In spite of 50 years of extensive use of penicillin, group A streptococci remain exquisitely susceptible to this antibiotic. This observation that continuing susceptibility has occurred despite the development of resistance to other antimicrobial agents prompted a day-long meeting at Rockefeller University (New York) in October 1996. Among the most likely explanations for this remarkable state of continued susceptibility to penicillin are that beta-lactamase may not be expressed or may be toxic to the organism and/or that low-affinity penicillin-binding proteins either are not expressed or render organisms nonviable. Other potential explanations are that circumstances favorable for the development of resistance have not yet occurred and/or that there are inefficient mechanisms for or barriers to genetic transfer. Recommended future actions include (1) additional laboratory investigations of gene transfer, penicillin-binding proteins, virulence factors, and homeologous recombination and mismatch repair; (2) increased surveillance for the development of penicillin resistance; (3) application of bioinformatics to analyze streptococcal genome sequences; and (4) development of vaccines and novel antimicrobial agents. Thus far the susceptibility of group A streptococci to penicillin has not been a major clinical or epidemiological problem. A similar observation, however, could have been made decades ago about Streptococcus pneumoniae. It is therefore vital for the scientific community to closely examine why penicillin has remained uniformly highly active against group A streptococci in order to maintain this desirable state.

Antiendotoxin strategies for the prevention and treatment of septic shock. New approaches and future directions

Therapy for Gram-negative sepsis remains unsatisfactory despite a concerted effort to develop new treatments for this common, life-threatening syndrome. Current research continues on several fronts to improve the treatment options available to clinicians in the management of these critically ill patients. Recently, a greater understanding of the complex molecular basis of endotoxin-mediated pathophysiological effects in humans has generated a number of novel therapeutic agents for sepsis. Several of these treatment strategies have already entered clinical trials and it is hoped that some of these therapies will become widely available in the near future. In this review, the current status of the most promising new antiendotoxin agents is summarised, and the major obstacles to the successful clinical development of these therapies are described. New antiendotoxin therapies include those which interrupt the synthesis of endotoxin, bind and neutralise its activity, prevent endotoxin interactions with host effector cells and interfere with endotoxin-mediated signal transduction pathways. Potential therapeutic strategies involving these agents consist of endotoxin analogues, antibodies, subunit vaccines, binding columns, recombinant human proteins and small molecule inhibitors of endotoxin synthesis and intracellular signalling. The pitfalls of previous antiendotoxin clinical investigations and the perils of future clinical trial designs are discussed in the context of unmet needs and realistic expectations for success. While considerable progress has been made, effective and new treatments for Gram-negative bacterial sepsis continues to elude us at the present time. This has been to the detriment of patients, investigators and pharmaceutical companies alike. It will require focused efforts by basic scientists, continued support by industry and enlightened study designs by clinical investigators to successfully develop antiendotoxin in therapies for use in septic patients in the future.

Mechanisms for virus-induced liver disease: tumor necrosis factor-mediated pathology independent of natural killer and T cells during murine cytomegalovirus infection

The contribution of endogenous NK cells and cytokines to virus-induced liver pathology was evaluated during murine cytomegalovirus infections of mice. In immunocompetent C57BL/6 mice, the virus induced a self-limited liver disease characterized by hepatitis, with focal inflammation, and large grossly visible subcapsular necrotic foci. The inflammatory foci were most numerous and contained the greatest number of cells 3 days after infection; they colocalized with areas of viral antigen expression. The largest number of necrotic foci was found 2 days after infection. Overall hepatic damage, assessed as increased expression of liver enzymes in serum, accompanied the development of inflammatory and necrotic foci. Experiments with neutralizing antibodies demonstrated that although virus-induced tumor necrosis factor (TNF) can have antiviral effects, it also mediated significant liver pathology. TNF was required for development of hepatic necrotic foci and increased levels of liver enzymes in serum but not for increased numbers of inflammatory foci. The necrotic foci and liver enzyme indications of pathology occurred independently of NK and T cells, because mice rendered NK-cell deficient by treatment with antibodies, T- and B-cell-deficient Rag-/- mice, and NK- and T-cell-deficient E26 mice all manifested both parameters of disease. Development of necrotic foci and maximally increased levels of liver enzymes in serum also were TNF dependent in NK-cell-deficient mice. Moreover, in the immunodeficient E26 mice, virus-induced liver disease was progressive, with eventual death of the host, and neutralization of TNF significantly increased longevity. These results establish conditions separating hepatitis from significant liver damage and demonstrate a cytokine-mediated component to viral pathogenesis.

Confirmatory interleukin-1 receptor antagonist trial in severe sepsis: a phase III, randomized, double-blind, placebo-controlled, multicenter trial. The Interleukin-1 Receptor Antagonist Sepsis Investigator Group

OBJECTIVE

To determine the therapeutic efficacy and safety of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) in the treatment of patients with severe sepsis.

DESIGN

Prospective, randomized, double-blind, placebo-controlled, multicenter trial with a planned, midstudy, interim analysis.

SETTING

Ninety-one academic medical center intensive care units in North America and Europe.

PATIENTS

Patients with severe sepsis or septic shock (n = 696) received standard supportive care and antimicrobial therapy for sepsis, in addition to rhIL-1ra or placebo.

INTERVENTIONS

Patients were randomized to receive either rhIL-1ra (100 mg) or placebo (vehicle) by intravenous bolus, followed by a 72-hr continuous intravenous infusion of either rhIL-1ra (2.0 mg/kg/hr) or placebo.

MEASUREMENTS AND MAIN RESULTS

The study was terminated after an interim analysis found that it was unlikely that the primary efficacy end points would be met. The 28-day, all-cause mortality rate was 33.1% (116/350) in the rhIL-1ra treatment group, while the mortality rate in the placebo group was 36.4% (126/346), yielding a 9% reduction in mortality rate (p = .36). The patients were well matched at the time of study entry; 52.9% of placebo-treated patients were in shock while 50.9% of rhIL-1ra-treated patients were in shock at the time of study entry (p = .30). The mortality rate did not significantly differ between treatment groups when analyzed on the basis of site of infection, infecting microorganism, presence of bacteremia, shock, organ dysfunction, or predicted risk of mortality at the time of study entry. No excess number of adverse reactions or microbial superinfections were attributable to rhIL-1ra treatment in this study.

CONCLUSIONS

A 72-hr, continuous intravenous infusion of rhIL-1ra failed to demonstrate a statistically significant reduction in mortality when compared with standard therapy in this multicenter clinical trial. If rhIL-1ra treatment has any therapeutic activity in severe sepsis, the incremental benefits are small and will be difficult to demonstrate in a patient population as defined by this clinical trial.

Characterization of early cytokine responses and an interleukin (IL)-6-dependent pathway of endogenous glucocorticoid induction during murine cytomegalovirus infection

Early infection with murine cytomegalovirus (MCMV) induces circulating levels of interleukin (IL)-12, interferon (IFN)-gamma, and tumor necrosis factor (TNF). Studies presented here further characterize these responses by defining kinetics and extending evaluation to include IL-1, IL-6, and glucocorticoids. IL-12 p40, IFN-gamma, TNF, IL-1alpha, and IL-6 were shown to be increased, but IL-1beta was undetectable, in serum of MCMV-infected mice. The IL-12 p40, IFN-gamma, TNF, and IL-6 responses were dramatic with peak levels reaching >150-10,000 pg/ml at 32-40 h after infection and rapidly declining thereafter. Glucocorticoid induction, peaking at 36 h and reaching 30-fold increases above control values, accompanied the cytokine responses. Mice with cytokine deficiencies or neutralized cytokine function demonstrated that IL-6 was the pivotal mediator of the glucocorticoid response, with IL-1 contributing to IL-6 production. The IL-6 requirement appeared to be specific for virus-type stimuli as the synthetic analogue of viral nucleic acid, polyinosinic-polycytidylic acid, also induced IL-6-dependent glucocorticoid release, but treatments with the bacterial product lipopolysaccharide and a non-immune physical restraint stressor elicited IL-6-independent responses. Collectively, the results identify IL-6 as a primary mediator of glucocorticoid induction, and elucidate specific pathways of interactions between immune and neuroendocrine systems during viral infection.

Treatment of septic shock with the tumor necrosis factor receptor:Fc fusion protein. The Soluble TNF Receptor Sepsis Study Group

BACKGROUND

A recombinant, soluble fusion protein that is a dimer of an extracellular portion of the human tumor necrosis factor (TNF) receptor and the Fc portion of IgG1 (TNFR:Fc) binds and neutralizes TNF-alpha and prevents death in animal models of bacteremia and endotoxemia.

METHODS

To evaluate the safety and efficacy of TNFR:Fc in the treatment of septic shock, we conducted a randomized, double-blind, placebo-controlled, multicenter trial. A total of 141 patients were randomly assigned to receive either placebo or a single intravenous infusion of one of three doses of TNFR:Fc (0.15, 0.45, or 1.5 mg per kilogram of body weight). The primary end point was mortality from all causes at 28 days.

RESULTS

There were 10 deaths among the 33 patients in the placebo group (30 percent mortality), 9 deaths among the 30 patients receiving the low dose of TNFR:Fc (30 percent mortality), 14 deaths among the 29 receiving the middle dose (48 percent mortality), and 26 deaths among the 49 receiving the high dose (53 percent mortality) (P = 0.02 for the dose-response relation). Baseline differences in the severity of illness did not account for the increased mortality in the groups receiving the higher doses of TNFR:Fc.

CONCLUSIONS

In patients with septic shock, treatment with the TNFR:Fc fusion protein does not reduce mortality, and higher doses appear to be associated with increased mortality.

Potential hazards of combination immunotherapy in the treatment of experimental septic shock

Using an actual infection model of Pseudomonas aeruginosa sepsis in neutropenic rats, the potential utility of a combination anticytokine approach for the treatment of sepsis was tested. A dimeric tumor necrosis factor binding protein (TNF-BP) consisting of two soluble recombinant human TNF type 1 receptors linked with polyethylene glycol was used with recombinant human interleukin-1 receptor antagonist (IL-1ra). Despite having levels of bacteremia and endotoxemia similar to the control group (survivors, 0/18), 30% of IL-1ra-treated animals survived (P < .05); 31% of TNF-BP-treated animals survived (P < .01). Unexpectedly, the combination of IL-1ra plus TNF-BP proved to be uniformly fatal (survivors, 0/20). Endotoxin (P < .0001) and bacteremia (P < .01) levels were >10-fold higher than levels in animals treated with IL-1ra alone, TNF-BP alone, or placebo. Disseminated microabscesses in major organs were found in animals treated with combination immunotherapy. Combination anticytokine therapy may exacerbate systemic infection and worsen outcome in experimental sepsis.

A noncovalent complex vaccine prepared with detoxified Escherichia coli J5 (Rc chemotype) lipopolysaccharide and Neisseria meningitidis Group B outer membrane protein produces protective antibodies against gram-negative bacteremia

Earlier studies showed that purified IgG from sera of rabbits immunized with a boiled Escherichia coli J5 (Rc chemotype) whole cell vaccine protected neutropenic rats against gram-negative bacterial sepsis. In the present study, de-O-acylated J5 lipopolysaccharide (J5 DLPS) as a noncovalent complex with Neisseria meningitidis group B outer membrane protein (GBOMP) elicited anti-J5 LPS antibodies in rabbits. IgG prepared from immune rabbit sera protected neutropenic rats against lethal challenge with Pseudomonas aeruginosa 12:4:4 (Fisher Devlin immunotype 6). Sixteen of 26 rats treated with the postimmune serum IgG were protected compared with none of 20 rats treated with the control rabbit serum IgG (P < .001). In vitro binding studies showed binding of anti-J5 IgG to several gram-negative bacteria. These results indicate that a subunit vaccine made of J5 DLPS as a noncovalent complex with GBOMP may protect against gram-negative bacteremia.

Antibiotics, cytokines, and endotoxin: a complex and evolving relationship in gram-negative sepsis

Compelling experimental evidence now exists that antimicrobial agents induce the release of endotoxin from Gram-negative bacteria during the process of bacteriolysis. Different antimicrobial classes, particularly those which act upon the outer membrane of bacteria, vary in the amount of free endotoxin released from Gram-negative organisms. Despite this in vitro evidence, clinically important consequences of antibiotic-induced endotoxin release have yet to be consistently documented. Complexities in the host-pathogen interactions during actual infection with Gram-negative bacteria may account for the difficulties in demonstrating this phenomena in vivo. This brief review analyses these interactions and defines clinical settings where antibiotic-induced endotoxin release may prove to be clinically relevant.

Activity of lipopolysaccharide-binding protein-bactericidal/permeability-increasing protein fusion peptide in an experimental model of Pseudomonas sepsis

A chimeric protein consisting of the N-terminal domain of lipopolysaccharide-binding protein and the C-terminal domain of bactericidal/permeability-increasing protein demonstrated a dose-dependent survival benefit (P = 0.001) and reduced endotoxin levels (P < 0.01) in neutropenic rats with Pseudomonas aeruginosa sepsis. This lipopolysaccharide-binding protein-bactericidal/ permeability-increasing peptide has favorable pharmacokinetics and antiendotoxin properties which may be of value for human sepsis.

Antibiotic-induced D-lactic acidosis

OBJECTIVE

To describe a case of oral antibiotic-induced D-lactic acidosis in a patient with enteric overgrowth of Lactobacillus acidophilus.

DESIGN

Single case study.

SETTING

University-affiliated community hospital.

INTERVENTION

Oral carbohydrate challenge test with 4000 kcal/d.

MAIN RESULTS

A patient had several episodes of D-lactic acidosis after receiving oral antibiotics. Stool cultures yielded Lactobacillus acidophilus resistant to the implicated agents. Provocative challenge with dietary carbohydrate alone, in the absence of antibiotics, failed to reproduce the syndrome.

CONCLUSIONS

Oral antibiotics may induce D-lactic acidosis in patients with the short-bowel syndrome by promoting the overgrowth of resistant D-lactate-producing organisms. Interactions between carbohydrate intake and antibiotic use are likely determinants in the development of this syndrome. Periodic use of stool cultures with antimicrobial susceptibility testing may assist in the management of these patients by optimizing the selection of antimicrobial agents.

Clinical characteristics, management strategies, and cost implications of a statewide outbreak of enterovirus meningitis

A statewide outbreak of enterovirus meningitis occurred in Rhode Island in the summer of 1991. A comprehensive chart review was conducted for determining the demographic and clinical characteristics of the epidemic and for assessing the interinstitutional variation in treatment strategies. Four hundred eight cases were reported, and enteroviruses were recovered in 61 (68%) of 90 cases in which viral isolation was attempted. Of six isolates that were serotyped, all were echovirus 30. Analysis of cerebrospinal fluid revealed that an increased total white blood cell count and an increased protein concentration were associated with increasing patient age; however, the percentage of polymorphonuclear leukocytes in the cerebrospinal fluid decreased with increasing patient age and longer durations of illness. Marked variations in treatment strategies between institutions were noted in the use of computed tomography of the head, the administration of empirical antimicrobial agents, and the duration of hospitalization. Considerable health resources could have been saved by rapid detection of the virus, dissemination of information about the outbreak, and a conservative approach to clinical management.

Mechanism of interleukin 12-mediated toxicities during experimental viral infections: role of tumor necrosis factor and glucocorticoids

Interleukin 12 (IL-12) doses in excess of 100 ng/d have been shown to induce profound immunotoxicities in mice infected with lymphocytic choriomeningitis virus (LCMV). These immunotoxicities are characterized by almost complete inhibition of virus-induced CD8+ T cell expansion and CTL activation, and up to 2 log increases in viral replication. They are accompanied by induction of serum tumor necrosis factor (TNF). The studies presented here were undertaken to characterize mechanisms for the IL-12-induced toxicities and to examine expression and function of TNF in this context. Several physiological changes were induced in IL-12-treated uninfected and dramatically elevated in IL-12-treated virus-infected mice. IL-12 induced (a) decreases in body weights, > 10% in uninfected and > 20% in LCMV-infected mice; (b) elevation of circulating glucocorticoid levels to > 10 micrograms/dl in uninfected and > 20 micrograms/dl in infected mice; and (c) decreases in thymic mass, > 30% in uninfected and up to 95% in infected mice. These changes are known to be associated with circulating TNF. Northern blot and in situ hybridization analyses demonstrated that IL-12 induced TNF-alpha expression and that LCMV infection synergized with IL-12 for induction of this factor. Antibodies neutralizing TNF reversed all of the IL-12-induced toxicities in LCMV-infected mice including the immunotoxicities against CD8+ T cells and anti-viral defenses. The TNF-mediated immunotoxicities appeared to result from an induced cellular sensitivity to the factor, as splenic leukocytes and CD8+ T cell subsets isolated from LCMV-infected mice were more sensitive to TNF-mediated cytotoxicity in culture than were equivalent populations prepared from uninfected mice. Experiments with the glucocorticoid type II receptor antagonist, RU486, demonstrated that endogenous glucocorticoids were secondary intermediaries in IL-12-induced thymic atrophy. Studies in IL-2-deficient mice showed that the synergism was dependent upon endogenous IL-2. The results delineate a unique mechanism of TNF-mediated toxicity. In addition, they have significant implications concerning potential detrimental consequences of in vivo TNF induction and of IL-12 administration for protective anti-viral responses.

Affinity-purified Escherichia coli J5 lipopolysaccharide-specific IgG protects neutropenic rats against gram-negative bacterial sepsis

Antibodies were raised in rabbits by immunization with the heat-killed J5 mutant of Escherichia coli O111 (Rc chemotype). Serum antibodies were separated into purified IgG and IgM by sequential affinity chromatography on protein G-Sepharose and anti-rabbit IgG-Sepharose columns. J5 lipopolysaccharide (LPS)-specific IgG was prepared by affinity chromatography of purified IgG on a J5 LPS-EAH Sepharose 4B affinity column. Purified IgM, IgG, and J5 LPS-specific IgG protected neutropenic rats against lethal challenge with Pseudomonas aeruginosa 12:4:4 (Fisher Devlin immunotype 6). Nine of 16 rats treated with the IgM fraction were protected (P < .001). Thirteen of 20 rats treated with the purified IgG and 6 of 8 treated with J5 LPS-specific IgG were protected compared with none of 25 treated with IgG made from the preimmune serum of the same rabbit (P < .001). These results demonstrate that purified J5 LPS-specific IgG protects against the lethal consequences of gram-negative bacteremia.

Role of interleukin-1 and the therapeutic potential of interleukin-1 receptor antagonist in sepsis

Clinical trials of anticytokines in sepsis have not been as straightforward as had been anticipated from results in animal models of sepsis and the role of cytokines in sepsis is now in question. Retrospective analysis of the results of a phase III trial of interleukin-1 (IL-1) receptor antagonist suggests that sepsis-induced adult respiratory distress syndrome (ARDS), disseminated intravascular coagulation (DIC), renal dysfunction, and shock are valuable markers of patients in whom IL-1 is a pathogenic mediator and in whom IL-1ra can reduce mortality. A re-examination of the effects of IL-1ra in animal models of sepsis supports the validity of this analysis. A new phase III clinical trial will confirm or disprove the hypothesis that IL-1 is a mediator of pathology, and IL-1ra is a valuable therapy for sepsis complicated by ARDS, DIC, renal dysfunction, or shock.