PubMed Health⌕ Search

Biomedical subjects

Steve E Calvano

Publications and source records attributed to Steve E Calvano.

At least 19 recordsLinked to original sources
PubMed2006

Cell-specific expression and pathway analyses reveal alterations in trauma-related human T cell and monocyte pathways.

Monitoring genome-wide, cell-specific responses to human disease, although challenging, holds great promise for the future of medicine. Patients with injuries severe enough to develop multiple organ dysfunction syndrome have multiple immune derangements, including T cell apoptosis and anergy combined with depressed monocyte antigen presentation. Genome-wide expression analysis of highly enriched circulating leukocyte subpopulations, combined with cell-specific pathway analyses, offers an opportunity to discover leukocyte regulatory networks in critically injured patients. Severe injury induced significant changes in T cell (5,693 genes), monocyte (2,801 genes), and total leukocyte (3,437 genes) transcriptomes, with only 911 of these genes common to all three cell populations (12%). T cell-specific pathway analyses identified increased gene expression of several inhibitory receptors (PD-1, CD152, NRP-1, and Lag3) and concomitant decreases in stimulatory receptors (CD28, CD4, and IL-2Ralpha). Functional analysis of T cells and monocytes confirmed reduced T cell proliferation and increased cell surface expression of negative signaling receptors paired with decreased monocyte costimulation ligands. Thus, genome-wide expression from highly enriched cell populations combined with knowledge-based pathway analyses leads to the identification of regulatory networks differentially expressed in injured patients. Importantly, application of cell separation, genome-wide expression, and cell-specific pathway analyses can be used to discover pathway alterations in human disease.

Gene Expression Profiling↗
PubMed2006

Response to systemic endotoxemia among humans bearing polymorphisms of the Toll-like receptor 4 (hTLR4).

Mutations (Asp299Gly and Thr399Ile) in the human Toll-like receptor 4 (hTLR4) gene are reportedly associated with hyporesponsiveness to inhaled LPS in humans. It was hypothesized that normal volunteers with these hTLR4 mutations would manifest altered physiological responses to intravenous LPS administration. Human subjects (n = 57) were administered LPS (2 ng/kg) intravenously and monitored for vital signs (temperature, heart rate, mean arterial pressure). Blood-derived genomic DNA samples were evaluated using PCR to detect hTLR4 and TLR2 mutations. Heterozygous hTLR4 mutations were identified in 8 of the 57 subjects studied. Subjects with hTLR4 mutations demonstrated similar responses to LPS administration. The moderate systemic inflammatory response produced by intravenous LPS administration in human subjects is not modulated by the presence of heterozygous mutations in the hTLR4 gene.

Adult↗
PubMed2006

Polymorphisms of heat shock protein-70 (HSPA1B and HSPA1L loci) do not influence infection or outcome risk in critically ill surgical patients.

Heat shock proteins (HSP) are induced in various stress conditions and have many cytoprotective effects, including formation of protein complexes for antigen presentation, stabilizing intracellular proteins, and facilitating protein folding. The HSP-70 gene exhibits polymorphisms at the HSPA1B and HSPA1L loci that reportedly influence cytokine levels and clinical outcomes in critically ill patients. These HSP variations also have been linked to TNF-beta polymorphisms associated with poor outcomes. This study further evaluated outcomes and risk of infection of HSP polymorphisms in critically ill patients. Seventy-six consecutive surgical intensive care unit uninfected patients with established systemic inflammatory response features were prospectively enrolled. Genomic DNA was isolated from whole blood samples and specific fragments, including the relevant polymorphic sites, were amplified by PCR, and restriction digestions were performed. Genotypes were determined by electrophoresis and all were confirmed by direct sequencing. Plasma cytokine levels for TNF-alpha were assayed in a subset of patients by enzyme-linked immunoabsorbent assay. None of the HSP alleles bore a significant relationship to nosocomial infection rates, organ specific dysfunctions, or mortality. No linkage of HSP genotype to common TNF-alpha or TNF-beta genotypes could be demonstrated, although the HSPA1L CT polymorphism was associated with higher levels of TNF-alpha compared with the TT genotype. These data suggest that polymorphisms of the HSPA1L or HSPA1B loci do not influence infection or other highly morbid outcomes in surgical intensive care unit patients.

Aged↗
PubMed2006

Tumor necrosis factor receptor regulation of bone marrow cell apoptosis during endotoxin-induced systemic inflammation.

Although inflammation-induced release of cells from the bone marrow (BM) is well established, less is known regarding inflammation-induced modulation of bone marrow cell numbers by apoptosis. The purpose of this study is to assess apoptosis of BM immature and mature myeloid cells and peripheral granulocytes, and to elucidate the role(s) of TNFR-p55 and TNFR-p75 as modulators of apoptosis in these cellular compartments in a mouse model of endotoxin-induced systemic inflammation. Gene knockout (p55(-/-), p75(-/-), and p55(-/-)/p75(-/-)), or wild-type (WT) mice were injected i.p. with saline (Sal) or LPS (4 microg/g) followed by collection of BM cells and peripheral blood after 24 h. Apoptosis was assessed by propidium iodide staining using two-color flow cytometry with differentiated granulocyte-specific Gr1-fluorescein isothiocyanate. Repeated-measures analysis of variance and Neuman-Keuls post hoc test were used for statistical analyses. After i.p. LPS, apoptosis was induced to the higher level in BM Gr1(-) cells than in BM Gr1(+) cells and was not induced in peripheral Gr1(+) cells. Depletion of cell numbers in both BM Gr1(-) and Gr1(+) subpopulations after LPS treatment was consistent with increase of the apoptotic cell percentages in the groups. LPS-induced apoptosis was significantly lower in Gr1(-) cells from the -p55(-/-)/LPS and p55(-/-)/p75(-/-)/LPS mice but not from p75(-/-)/LPS mice as compared with WT/LPS mice, whereas there was no difference in apoptosis of BM Gr1(+) and peripheral Gr1(+) cells among WT groups and knockout groups. Thus, apoptosis of myeloid cells during endotoxemia is minimized because these cells undergo differentiation, which in turn may be because of the attenuation of the proapoptotic effect of TNFR-p55 shown herein to occur with myeloid differentiation. In contrast, TNFR-p75 seems to play a minimal role in apoptosis induction in Gr1(-) myeloid cells during endotoxemia. One explanation for a decrease in BM cell numbers during endotoxemia may be via induction of apoptosis in immature myeloid cells.

Animals↗
PubMed2006

Gender influences in vivo human responses to endotoxin.

Gender appears to influence systemic and organ-specific inflammatory sequelae of ischemia-reperfusion and infectious challenge in many animal models. Despite the protection provided by female gender, androgen blockade, and/or estrogen administration in such experimental studies, many questions remain regarding the influence of gender dimorphism upon human responses to injury. We hypothesized that the administration of low-dose lipopolysaccharide (LPS) to otherwise healthy, young adults would provide insights regarding the influence of gender upon physiological and innate immune system responses to a prototypic inflammatory stimulus. To this end, 72 adult subjects (48 men, aged 29 +/- 1.0 years; 24 women, aged 26 +/- 1.0 years) were prospectively evaluated before and after the i.v. administration of LPS (2 ng/kg). All subjects developed symptoms within 1.0 to 1.5 h after LPS, and the men exhibited a greater increase in core temperature (2.1 +/- 0.1 degrees C) compared with the women (1.4 +/- 0.1 degrees C) (P < 0.001). In addition, the men exhibited a greater maximum decrease in mean arterial pressure (-13.0 +/- 1.3 mmHg) compared with the women (-8 +/- 1.3 mmHg) (P < 0.02). The changes in temperature and mean arterial pressure occurred without detectable differences between the male and female cohort responses of circulating white blood cell count and cortisol or cytokine levels. These results suggest that soluble inflammatory mediators generated by in vivo endotoxin activation of the innate immune system are insufficient to explain the resultant gender-specific phenotypic differences observed in young, adult humans.

Adult↗
PubMed2005

Selective activation of peripheral blood T cell subsets by endotoxin infusion in healthy human subjects corresponds to differential chemokine activation.

Although activation of human innate immunity after endotoxin administration is well established, in vivo endotoxin effects on human T cell responses are not well understood. Most naive human T cells do not express receptors for LPS, but can respond to endotoxin-induced mediators such as chemokines. In this study, we characterized the in vivo response of peripheral human T cell subsets to endotoxin infusion by assessing alterations in isolated T cells expressing different phenotypes, intracellular cytokines, and systemic chemokines concentration, which may influence these indirect T cell responses. Endotoxin administration to healthy subjects produced T cell activation as confirmed by a 20% increase in intracellular IL-2, as well as increased CD28 and IL-2R alpha-chain (CD25) expression. Endotoxin induced indirect activation of T cells was highly selective among the T cell subpopulations. Increased IL-2 production (36.0 +/- 3.7 to 53.2 +/- 4.1) vs decreased IFN-gamma production (33.8 +/- 4.2 to 19.1 +/- 3.2) indicated selective Th1 activation. Th2 produced IL-13 was minimally increased. Differentially altered chemokine receptor expression also indicated selective T cell subset activation and migration. CXCR3+ and CCR5+ expressing Th1 cells were decreased (CXCR3 44.6 +/- 3.2 to 33.3 +/- 4.6 and CCR5 24.8 +/- 2.3 to 12 +/- 1.4), whereas plasma levels of their chemokine ligands IFN-gamma-inducible protein 10 and MIP-1alpha were increased (61.4 +/- 13.9 to 1103.7 +/- 274.5 and 22.8 +/- 6.2 to 55.7 +/- 9.5, respectively). In contrast, CCR4+ and CCR3 (Th2) proportions increased or remained unchanged whereas their ligands, eotaxin and the thymus and activation-regulated chemokine TARC, were unchanged. The data indicate selective activation among Th1 subpopulations, as well as differential Th1/Th2 activation, which is consistent with a selective induction of Th1 and Th2 chemokine ligands.

Adult↗
PubMed2005

A network-based analysis of systemic inflammation in humans.

Oligonucleotide and complementary DNA microarrays are being used to subclassify histologically similar tumours, monitor disease progress, and individualize treatment regimens. However, extracting new biological insight from high-throughput genomic studies of human diseases is a challenge, limited by difficulties in recognizing and evaluating relevant biological processes from huge quantities of experimental data. Here we present a structured network knowledge-base approach to analyse genome-wide transcriptional responses in the context of known functional interrelationships among proteins, small molecules and phenotypes. This approach was used to analyse changes in blood leukocyte gene expression patterns in human subjects receiving an inflammatory stimulus (bacterial endotoxin). We explore the known genome-wide interaction network to identify significant functional modules perturbed in response to this stimulus. Our analysis reveals that the human blood leukocyte response to acute systemic inflammation includes the transient dysregulation of leukocyte bioenergetics and modulation of translational machinery. These findings provide insight into the regulation of global leukocyte activities as they relate to innate immune system tolerance and increased susceptibility to infection in humans.

Acute Disease↗
PubMed2005

Application of genome-wide expression analysis to human health and disease.

The application of genome-wide expression analysis to a large-scale, multicentered program in critically ill patients poses a number of theoretical and technical challenges. We describe here an analytical and organizational approach to a systematic evaluation of the variance associated with genome-wide expression analysis specifically tailored to study human disease. We analyzed sources of variance in genome-wide expression analyses performed with commercial oligonucleotide arrays. In addition, variance in gene expression in human blood leukocytes caused by repeated sampling in the same subject, among different healthy subjects, among different leukocyte subpopulations, and the effect of traumatic injury, were also explored. We report that analytical variance caused by sample processing was acceptably small. Blood leukocyte gene expression in the same individual over a 24-h period was remarkably constant. In contrast, genome-wide expression varied significantly among different subjects and leukocyte subpopulations. Expectedly, traumatic injury induced dramatic changes in apparent gene expression that were greater in magnitude than the analytical noise and interindividual variance. We demonstrate that the development of a nation-wide program for gene expression analysis with careful attention to analytical details can reduce the variance in the clinical setting to a level where patterns of gene expression are informative among different healthy human subjects, and can be studied with confidence in human disease.

Cluster Analysis↗
PubMed2005

Quantitative proteome analysis of human plasma following in vivo lipopolysaccharide administration using 16O/18O labeling and the accurate mass and time tag approach.

Identification of novel diagnostic or therapeutic biomarkers from human blood plasma would benefit significantly from quantitative measurements of the proteome constituents over a range of physiological conditions. Herein we describe an initial demonstration of proteome-wide quantitative analysis of human plasma. The approach utilizes postdigestion trypsin-catalyzed 16O/18O peptide labeling, two-dimensional LC-FTICR mass spectrometry, and the accurate mass and time (AMT) tag strategy to identify and quantify peptides/proteins from complex samples. A peptide accurate mass and LC elution time AMT tag data base was initially generated using MS/MS following extensive multidimensional LC separations to provide the basis for subsequent peptide identifications. The AMT tag data base contains >8,000 putative identified peptides, providing 938 confident plasma protein identifications. The quantitative approach was applied without depletion of high abundance proteins for comparative analyses of plasma samples from an individual prior to and 9 h after lipopolysaccharide (LPS) administration. Accurate quantification of changes in protein abundance was demonstrated by both 1:1 labeling of control plasma and the comparison between the plasma samples following LPS administration. A total of 429 distinct plasma proteins were quantified from the comparative analyses, and the protein abundances for 25 proteins, including several known inflammatory response mediators, were observed to change significantly following LPS administration.

Blood Proteins↗
PubMed2005

Comparative proteome analyses of human plasma following in vivo lipopolysaccharide administration using multidimensional separations coupled with tandem mass spectrometry.

There is significant interest in characterization of the human plasma proteome due to its potential for providing biomarkers applicable to clinical diagnosis and treatment and for gaining a better understanding of human diseases. We describe here a strategy for comparative proteome analyses of human plasma, which is applicable to biomarker identifications for various disease states. Multidimensional liquid chromatography-mass spectrometry (LC-MS/MS) has been applied to make comparative proteome analyses of plasma samples from an individual prior to and 9 h after lipopolysaccharide (LPS) administration. Peptide peak areas and the number of peptide identifications for each protein were used to evaluate the reproducibility of LC-MS/MS and to compare relative changes in protein concentration between the samples following LPS treatment. A total of 804 distinct plasma proteins (not including immunoglobulins) were confidently identified with 32 proteins observed to be significantly increased in concentration following LPS administration, including several known inflammatory response or acute-phase mediators such as C-reactive protein, serum amyloid A and A2, LPS-binding protein, LPS-responsive and beige-like anchor protein, hepatocyte growth factor activator, and von Willebrand factor, and thus, constituting potential biomarkers for inflammatory response.

Blood Proteins↗
PubMed2005

Acute inflammatory response to endotoxin in mice and humans.

Endotoxin injection has been widely used to study the acute inflammatory response. In this study, we directly compared the inflammatory responses to endotoxin in mice and humans. Escherichia coli type O113 endotoxin was prepared under identical conditions, verified to be of equal biological potency, and used for both mice and humans. The dose of endotoxin needed to induce an interleukin-6 (IL-6) concentration in plasma of approximately 1,000 pg/ml 2 h after injection was 2 ng/kg of body weight in humans and 500 ng/kg in mice. Healthy adult volunteers were injected intravenously with endotoxin, and male C57BL/6 mice (n=4 to 12) were injected intraperitoneally with endotoxin. Physiological, hematological, and cytokine responses were determined. Endotoxin induced a rapid physiological response in humans (fever, tachycardia, and slight hypotension) but not in mice. Both mice and humans exhibited lymphopenia with a nadir at 4 h and recovery by 24 h. The levels of tumor necrosis factor (TNF) and IL-6 in plasma peaked at 2 h and returned to baseline levels by 4 to 6 h. IL-1 receptor antagonist RA and TNF soluble receptor I were upregulated in both mice and humans but were upregulated more strongly in humans. Mice produced greater levels of CXC chemokines, and both mice and humans exhibited peak production at 2 h. These studies demonstrate that although differences exist and a higher endotoxin challenge is necessary in mice, there are several similarities in the inflammatory response to endotoxin in mice and humans.

Adult↗
PubMed2004

Effects of drotrecogin alfa (activated) in human endotoxemia.

In a phase III clinical trial, drotrecogin alfa (activated) was shown to improve survival and promote faster improvement of cardiovascular and respiratory dysfunction in patients with severe sepsis. To further examine mechanisms involved in the action of this drug, a healthy human endotoxin model was used. Healthy volunteers (eight per group) received drotrecogin alfa (activated) or placebo intravenously for 8 h in a randomized, double-blind, controlled manner. After 2 h of study drug infusion, endotoxin (2 ng/kg) was infused and measurement of physiologic responses and biomarkers continued for 24 h. Consistent with results from severe sepsis clinical trials, drotrecogin alfa (activated) improved mean arterial pressure during the period of infusion after endotoxin exposure. In contrast to severe sepsis clinical trials using drotrecogin alfa (activated) but similar to another human endotoxin study, no significant antithrombotic, profibrinolytic, or anti-inflammatory effects were observed. These results suggest a novel role for drotrecogin alfa (activated) in the human endotoxin model.

Adolescent↗
PubMed2003

The mature bone morphogenetic protein-2 is aberrantly expressed in non-small cell lung carcinomas and stimulates tumor growth of A549 cells.

To help identify genes, which may regulate metastasis in lung cancer, we performed representational difference analysis between a patient-derived non-small cell lung carcinoma (NSCLC) and immortalized normal human bronchial epithelial cells. This analysis revealed that bone morphogenetic proteins-2/4 (BMP) mRNA was expressed in the lung carcinoma. BMP-2/4 are known to induce pluripotent cell differentiation, enhance cell migration and stimulate proliferation during embryonic development. Despite being powerful morphogens it is not known whether BMP-2/4 have significant biological activity in human carcinomas. Furthermore, it has not been established whether the mature active BMP-2/4 protein is aberrantly expressed in patient-derived tumors. The purpose of this study was to determine whether the expression of the mature BMP-2/4 protein is disregulated in human lung carcinomas and to establish whether it has adverse biological activity. This study reveals that the mature BMP-2 protein, but not BMP-4, is highly over-expressed in human NCSLC with little to no expression in normal lung tissue or benign lung tumors. The expression of BMP-2 localized specifically to the cancer cells. Recombinant BMP-2 stimulated in vitro, the migration and invasiveness of the A549 and H7249 human lung cancer cell lines. In vivo, recombinant BMP-2 enhanced the growth of tumors formed from A549 cells injected subcutaneously into nude mice. Furthermore, inhibition of BMP-2 activity with either recombinant noggin or anti-BMP-2 antibody resulted in a significant reduction in tumor growth. This study shows that expression of the mature BMP-2 protein is disregulated in the majority of NSCLC. BMP-2 enhancement of tumor cell migration and invasion, as well as stimulating tumor growth in vivo, suggests it has important biological activity in lung carcinomas.

Animals↗
PubMed2003

Influence of the TNF-alpha and TNF-beta polymorphisms upon infectious risk and outcome in surgical intensive care patients.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is a well-documented central inflammatory mediator in sepsis. Specific polymorphisms of the TNF-alpha and TNF-beta genes (TNF2 and LTA + 250, respectively) have been suggested to correlate with higher mortality in septic shock. This study sought to determine whether these polymorphisms of the TNF-alpha and -beta genes are associated with an increased risk of infection in an at-risk surgical intensive care population. MATERIALS AND METHODS: Forty-four consecutive patients with systemic inflammatory response syndrome were enrolled prospectively in the study. Genomic DNA was isolated from whole blood samples using standard phenol/chloroform extraction techniques. Specific fragments including the polymorphic sites of each gene were amplified by polymerase chain reaction, and restriction enzyme digestions were performed. Genotypes were determined by gel electrophoresis and confirmed by direct sequencing. RESULTS: Eighty-six percent of the patients were TNF1 homozygotes (G:G at -308 of the TNF-alpha promoter region), whereas 9% of the patients were homozygous for TNF2 (A:A). There was no difference in the incidence of sepsis, septic shock, or mortality between patients bearing the various alleles. Only 13.6% of the patients exhibited the G:G alleles for TNF-beta, whereas the homozygous A:A was present in 45.4% of the patients. CONCLUSION: The presence of the A allele at these polymorphic sites did not predispose critically ill surgical patients to either infection or septic shock.

Aged↗
PubMed2003

Fas-mediated neutrophil apoptosis and associated A1 protein expression during systemic inflammation are regulated independently of both tumor necrosis factor receptors.

TNFR-1 (p55) and Fas share a death domain which is critical for apoptosis signaling whereas TNFR-p55 and TNFR-2 (p75) can activate NF-kappaB leading to anti-apoptotic proteins expression such as A1. The purpose of this study was to elucidate the role(s) of TNFR-p55 and TNFR-p75 in Fas-mediated neutrophil apoptosis and A1 expression in a mouse model of endotoxemia. Gene knockout (KO) (p55-/-, p75-/-, p55(-/-)/p75(-/-)) or wild type (WT) mice were injected i.p. with saline or LPS (4 microg/g) followed by collecting peripheral blood after 24 h. Neutrophil apoptosis was assessed by propidium iodide staining using two-color flow cytometry with granulocyte-specific Gr1-FITC after 6-h whole blood culture with or without Fas agonist Jo2 (300 ng/ml) in the presence or absence of cycloheximide (CHX, 30 microg/ml). Membrane-associated receptors (Fas, TNFR-p55 and TNFR-p75) and cytoplasmic A1 expression of freshly isolated neutrophils were assessed by one-color flow cytometry and western blotting respectively. Compared with the group-WT/Sal, Jo2 induced apoptosis only in the presence of CHX (J+C). J+C-induced apoptosis was significantly lower in the group-p55(-/-)/Sal and p55(-/-)/p75(-/-)/Sal but not in the group-p75(-/-)/Sal. J+C-induced apoptosis was inhibited similarly in all the LPS-injected WT and KO mice. Strong A1 expression was also induced similarly in all the LPS-injected WT and KO mice. Fas and TNFR-p55 expression was normal and TNFR-p75 was significantly increased in all the LPS-injected WT and KO mice although absence of the appropriate surface receptors was confirmed in the KO mice. We conclude that p55 normally plays a proapoptotic role, but p75 appears to play a minimal role in Fas-mediated neutrophil apoptosis. During endotoxin-induced systemic inflammation, both TNFR-p55 and TNFR-p75 appear to be of minimal importance for modulation of Fas-mediated apoptosis and associated A1 protein expression despite normal Fas/TNFR-p55 and increased TNFR-p75 expression in neutrophils.

Animals↗
PubMed2003

Modulation of the lipopolysaccharide receptor complex (CD14, TLR4, MD-2) and toll-like receptor 2 in systemic inflammatory response syndrome-positive patients with and without infection: relationship to tolerance.

The lipopolysaccharide (LPS) receptor complex consists of two interacting receptors (CD14 and TLR4) and an associated protein (MD-2). When engaged by LPS, as in gram-negative infection, this complex transduces a signal detected by MyD88 and passed onward by a cascade of the IRAKs, TRAF6, and NIK, resulting in activation of NF-kappaB. A similar cascade, mediated by TLR2, occurs with ligands derived from gram-positive bacteria. In vitro studies of human monocytes have shown that TLR4 mRNA is paradoxically upregulated in response to "tolerizing" doses of LPS. This study evaluated changes in vivo of blood monocyte CD14, TLR4, TLR2, and MD-2 mRNA by reverse transcription followed by real-time polymerase chain reaction in surgical intensive care unit patients and in normal controls. In addition cell-surface receptor expression of TLR2, TLR4, and CD14 was assessed by flow cytometry in patients and normal controls. Inflammation-induced acute tolerance to LPS was evaluated by ex vivo whole blood tumor necrosis factor alpha production and was significantly reduced in patients compared with controls, confirming LPS hyporesponsiveness. Monocyte mRNA and cell-surface receptor expression of TLR4 were increased 2.4-fold (P < 0.05) and 1.7-fold (P <.002), respectively, in patients compared with normal controls. Monocyte TLR2 mRNA, MD-2 mRNA and CD14 and TLR2 cell-surface expression were not significantly changed compared with controls. The present study suggests that the acute inflammatory condition associated with peripheral cellular LPS hyporesponsiveness is neither specific to prior infectious challenge nor can be ascribed to significant alterations in expression of the cell-surface LPS binding complex proteins.

Antigens, Surface↗
PubMed2002

Human toll-like receptor 4 mutations but not CD14 polymorphisms are associated with an increased risk of gram-negative infections.

Human toll-like receptor 4 (hTLR4) and CD14 are known to be components of the lipopolysaccharide receptor complex. Our study investigated the association between TLR4 mutations (Asp299Gly and Thr399Ile) and CD14 polymorphism(s) with outcome in an intensive care unit (ICU) population at risk for sepsis. By use of a polymerase chain reaction-based restriction fragment-length polymorphism analysis technique, the hTLR4 gene was altered in 14 (18%) of 77 ICU patients (all positive for systemic inflammatory response syndrome) and in 5 (13%) of 39 volunteers. There was a significantly higher incidence of gram-negative infection among patients with the mutations (11 [79%] of 14), compared with that in the wild-type population (11 [17%] of 63; P=.004). No association between CD14 polymorphism(s) and the incidence of infection or outcome was observed. These findings indicate that hTLR4 mutations are associated with an increased incidence of gram-negative infections in critically ill patients in a surgical setting.

Adult↗