Jan A. Hazelzet

4G/5G promoter polymorphism in the plasminogen-activator-inhibitor-1 gene and outcome of meningococcal disease

BACKGROUND Intravascular coagulation with infarction of skin, digits, and limbs is a characteristic feature of meningococcal sepsis. Children with meningococcal sepsis have higher than normal concentrations of plasminogen activator inhibitor 1 (PAI-1) in plasma. Combined with the widespread venous thrombosis, this finding suggests an impairment of fibrinolysis. A common functional insertion/deletion (4G/5G) polymorphism exists in the promoter region of the PAI-1 gene. We tested the hypothesis that children with the 4G/4G genotype produce higher concentrations of PAI-1, develop more severe coagulopathy, and are at greater risk of death during meningococcal sepsis. METHODS The relation between meningococcal disease outcome, PAI-1 concentration, and PAI-1 genotype was investigated in 175 children with meningococcal disease (37 from Rotterdam, the Netherlands, and 138 from London, UK) and 226 controls (137 from Rotterdam, 89 from London). PAI-1 concentrations in plasma were measured by ELISA, and the 4G/5G PAI-1 polymorphism was detected by PCR and hybridisation. FINDINGS Concentrations of PAI-1 on admission correlated with presentation (sepsis or meningitis) and outcome. The median PAI-1 concentration in children who died was substantially higher than that in survivors (2448 [IQR 1115-3191] vs 370 [146-914] ng/mL; p<0.0001). Patients with the 4G/4G genotype had significantly higher PAI-1 concentrations than those with the 4G/5G or 5G/5G genotype (1051 [550-2440] vs 436 [198-1225] ng/mL; p=0.03), and had an increased risk of death (relative risk 2.0 [1.0-3.8] for the two cohorts combined, and 4.8 [1.8-13] for the London cohort). INTERPRETATION A genetic predisposition to produce high concentrations of PAI-1 is associated with poor outcome of meningococcal sepsis. This finding suggests that impaired fibrinolysis is an important factor in the pathophysiology of meningococcal sepsis.

Activation of protein C following infusion of protein C concentrate in children with severe meningococcal sepsis and purpura fulminans: a randomized, double-blinded, placebo-controlled, dose-finding study

BACKGROUND Meningococcal septic shock in children results in high mortality and morbidity, and decreased protein C levels in these patients are associated with a poor outcome. We carried out a randomized, double-blinded, placebo-controlled study by supplying protein C concentrate. This phase 2 study was designed to assess the activation process of protein C and to study the dosing regimen of protein C concentrate in children with purpura fulminans and meningococcal septic shock in the perspective of a possible phase 3 trial. METHODS Forty children were randomized to receive placebo or protein C concentrate (200 IU/kg, 400 IU/kg, or 600 IU/kg), for a maximum of 7 days. Clinical and laboratory data, including plasma levels of protein C and activated protein C (APC), were collected at various time points. All patients received standard therapy for septic shock, including antibiotics, inotropic/vasoactive drugs, and blood products. RESULTS Increased APC levels relative to baseline were observed for the 27 of 28 patients treated with protein C concentrate, and the areas under the curve of protein C and APC were correlated with the dosage of protein C concentrate administered. Activation of coagulation, as evidenced by d-dimer levels, as well as the ratio of thrombin vs. APC normalized significantly faster with increasing dosages of protein C concentrate. No adverse reactions related to protein C concentrate were observed. Nine of the 40 (23%) patients died, and five survivors required amputations, with no differences in these rates among the randomized groups. Baseline APC levels were positively correlated with sequential organ failure assessment and pediatric risk of mortality scores and with d-dimers, tumor necrosis factor-alpha, interleukin-1, interleukin-6, interleukin-8, plasminogen activator inhibitor-1, TAT complexes, and PAP complexes. CONCLUSIONS Treatment with protein C concentrate is safe in children with purpura fulminans and meningococcal septic shock and leads to dose-related increases of plasma APC and resolution of coagulation imbalances.

Genome-wide association study identifies variants in the CFH region associated with host susceptibility to meningococcal disease

Meningococcal disease is an infection caused by Neisseria meningitidis. Genetic factors contribute to host susceptibility and progression to disease, but the genes responsible for disease development are largely unknown. We report here a genome-wide association study for host susceptibility to meningococcal disease using 475 individuals with meningococcal disease (cases) and 4,703 population controls from the UK. We performed, in Western European and South European cohorts (consisting of 968 cases and 1,376 controls), two replication studies for the most significant SNPs. A cluster of complement factor SNPs replicated independently in both cohorts, including SNPs within complement factor H (CFH) (rs1065489 (p.936D<E), P = 2.2 × 10−11) and in CFH-related protein 3 (CFHR3)(rs426736, P = 4.6 × 10−13). N. meningitidis is known to evade complement-mediated killing by the binding of host CFH to the meningococcal factor H–binding protein (fHbp). Our study suggests that host genetic variation in these regulators of complement activation plays a role in determining the occurrence of invasive disease versus asymptomatic colonization by this pathogen.

Host genetic determinants of Neisseria meningitidis infections

The clinical presentation of infections caused by Neisseria meningitidis is highly diverse. Some patients develop meningitis, and others present with sepsis or even septic shock. After invasion of the bloodstream by the bacteria, three main cascade pathways are activated. These are the complement system, the inflammatory response, and the coagulation and fibrinolysis pathway. These pathways do not act independently but are able to interact with each other. Genetic polymorphisms among components of these pathways have been shown to be involved in the susceptibility, severity, and outcome of meningococcal disease. We review knowledge of genetic variations associated with susceptibility to and severity of meningococcal infection. Complement deficiencies and defects in sensing or opsonophagocytic pathways, such as the rare Toll-like receptor 4 single nucleotide polymorphisms (SNPs) and combinations of inefficient variants of Fcgamma-receptors, seem to have the most important role in genetically established susceptibility. Effect on severity has repeatedly been reported for FcgammaRIIa and plasminogen activator inhibitor type 1 (PAI1) polymorphisms. Outcome effects have been confirmed for SNPs in properdin deficiencies, PAI1 and combination of the -511C/T SNP in interleukin 1beta, and the +2018C/T SNP in interleukin RN. Conflicting results are reported for the effect of the -308G/A promoter polymorphism in tumour necrosis factor (TNF) alpha. These differences may reflect discrepancies in group definitions between studies or the influence of additional SNPs in the TNFalpha promoter, which can form haplotypes representing different cytokine production capacity. For several SNPs, the potential effect on susceptibility, severity, or outcome has not yet been confirmed in an independent study.

Protein C and S deficiency in severe infectious purpura of children: A collaborative study of 40 cases

We studied, in 40 children (mean age: 52 months) with severe infectious purpura, the relationships between protein C (PC) and protein S (PS) levels, and shock, disseminated intravascular coagulation (DIC) and outcome. We determined, on admission, PC antigen (ELISA) and activity (chromogenic test), and total PS (ELISA). Results were expressed as % of normal adult values. Statistical analysis was performed with SAS. Thirty children were in shock, 20 had DIC. All children with DIC, and 10 without DIC were in shock. Of 20 children who were in shock and had DIC, 7 died and 3 had an amputation. PC antigen was significantly decreased in shock children (p<0.05), in children with DIC (p<0.0005). and in non-survivors (p<0.05). PC activity was significantly decreased in shock children (p<0.05), in children with DIC (p<0.0005), and in non-survivors (p<0.005). Total PS was not decreased in shock children, but was significantly decreased in children with DIC (p<0.005), and in non-survivors (p<0.005). We conclude that PC and PS levels were decreased in our children, and that PC levels were significantly decreased in the presence of shock, DIC, and fatal outcome. PC and antithrombin III (AT III) supplementation, should be evaluated in children with severe infectious purpura with shock and DIC.

One single dose of etomidate negatively influences adrenocortical performance for at least 24 h in children with meningococcal sepsis

ObjectiveTo investigate the effect of one single bolus of etomidate used for intubation on adrenal function in children with meningococcal sepsis.DesignRetrospective study conducted between 1997 and 2004.SettingUniversity-affiliated paediatric intensive care unit (PICU).Patients and participantsSixty children admitted to the PICU with meningococcal sepsis, not treated with steroids.InterventionsAdrenal hormone concentrations were determined as soon as possible after PICU admission, and after 12 h and 24 h. To assess disease severity, PRISM score and selected laboratory parameters were determined.Measurements and main resultsOn admission, before blood was drawn, 23 children had been intubated with etomidate, 8 without etomidate and 29 were not intubated. Children who were intubated had significantly higher disease severity parameters than those not intubated, whereas none of these parameters significantly differed between children intubated with or without etomidate. Children who received etomidate had significantly lower cortisol, higher ACTH and higher 11-deoxycortisol levels than those who did not receive etomidate. Arterial glucose levels were significantly lower in children who were intubated with etomidate than in non-intubated children. When children were intubated with etomidate, cortisol levels were 3.2 times lower for comparable 11-deoxycortisol levels. Eight children died, seven of whom had received etomidate. Within 24 h cortisol/ACTH and cortisol/11-deoxycortisol ratios increased significantly in children who received etomidate, but not in children who did not, resulting in comparable cortisol/ACTH ratios with still significantly lowered cortisol/11-deoxycortisol ratios 24 h after admission.ConclusionsOur data imply that even one single bolus of etomidate negatively influences adrenal function for at least 24 h. It might therefore increase risk of death.

Association between High Levels of Blood Macrophage Migration Inhibitory Factor, Inappropriate Adrenal Response, and Early Death in Patients with Severe Sepsis

BACKGROUND Identification of new therapeutic targets remains an imperative goal to improve the morbidity and mortality associated with severe sepsis and septic shock. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine and counterregulator of glucocorticoids, has recently emerged as a critical mediator of innate immunity and experimental sepsis, and it is an attractive new target for the treatment of sepsis. METHODS Circulating concentrations of MIF were measured in 2 clinical trial cohorts of 145 pediatric and adult patients who had severe sepsis or septic shock caused predominantly by infection with Neisseria meningitidis or other gram-negative bacteria, to study the kinetics of MIF during sepsis, to analyze the interplay between MIF and other mediators of sepsis or stress hormones (adrenocorticotropic hormone and cortisol), and to determine whether MIF is associated with patient outcome. RESULTS Circulating concentrations of MIF were markedly elevated in 96% of children and adults who had severe sepsis or septic shock, and they remained elevated for several days. MIF levels were correlated with sepsis severity scores, presence of shock, disseminated intravascular coagulation, urine output, blood pH, and lactate and cytokine levels. High levels of MIF were associated with a rapidly fatal outcome. Moreover, in meningococcal sepsis, concentrations of MIF were positively correlated with adrenocorticotropic hormone levels and negatively correlated with cortisol levels and the cortisol:adrenocorticotropic hormone ratio, suggesting an inappropriate adrenal response to sepsis. CONCLUSIONS MIF is markedly and persistently up-regulated in children and adults with gram-negative sepsis and is associated with parameters of disease severity, with dysregulated pituitary-adrenal function in meningococcal sepsis, and with early death.

Comparison of measured and predicted energy expenditure in mechanically ventilated children

Objective: To determine the energy requirements in mechanically ventilated pediatric patients using indirect calorimetry and to compare the results with the predicted metabolic rate. Design: In 50 mechanically ventilated children with a moderate severity of illness, energy expenditure was measured by indirect calorimetry. Daily caloric intake was recorded for all patients. Total urinary nitrogen excretion was determined in 31 patients. Results: Although there was a close correlation between the measured total energy expenditure (mTEE) and the predicted basal metabolic rate (pBMR) (r = 0.93, p < 0.001), Bland–Altman analysis showed lack of agreement between individual mTEE and pBMR values. The ratio of caloric intake/mTEE was significantly higher in the patients with a positive nitrogen balance (1.4 ± 0.07) compared with those with a negative nitrogen balance (0.8 ± 0.1; p < 0.001). Conclusions: Standard prediction equations are not appropriate to calculate the energy needs of critically ill, mechanically ventilated children. Individual measurements of energy expenditure and respiratory quotient by means of indirect calorimetry in combination with nitrogen balance are necessary for matching adequate nutritional support.

Serum lipids and disease severity in children with severe meningococcal sepsis

Objective:To evaluate the role of cholesterol and lipoproteins in children with severe meningococcal sepsis. Design:Retrospective observational study. Setting:A university-affiliated pediatric intensive care unit. Patients:Fifty-seven patients admitted to the pediatric intensive care unit with meningococcal sepsis or septic shock. Interventions:Total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) concentrations were measured in serum samples drawn within 6 hrs after admission to the pediatric intensive care unit and 12, 24, 48, 72 hrs, 7 days, and 1–3 months afterward. Standard deviation scores of these variables (sd scores) were calculated to correct for age-related differences. To assess disease severity, the Pediatric Risk of Mortality (PRISM) score, the Sepsis-related Organ Failure Assessment (SOFA) score, and the Disseminated Intravascular Coagulation (DIC) score were determined as well as selected laboratory variables. Measurements and Main Results:Ten patients died. Total serum cholesterol on admission was very low in all patients. This hypocholesterolemia was caused by low HDL concentrations but in particular by low LDL cholesterol levels. Eight patients had undetectable LDL levels on admission. Total cholesterol levels were significantly lower in nonsurvivors than in survivors (0.97 vs. 1.60, p = .013), whereas levels of LDL and HDL did not significantly differ between both groups. Total cholesterol sd scores were similar between survivors and nonsurvivors. Within survivors, cholesterol sd score was significantly lower in patients with shock compared with those with sepsis. The total cholesterol, HDL, and LDL levels correlated with clinical variables of disease severity and with levels of cytokines. Total cholesterol, HDL, and LDL levels normalized rapidly in survivors and were completely normal 1–3 months after admission. Conclusions:Extremely low levels of total serum cholesterol, HDL, and LDL are found in the initial phase of children with severe meningococcal disease. Total cholesterol levels are significantly lower in nonsurvivors than in survivors, but not the sd score. Total cholesterol, HDL, and LDL levels on admission are inversely associated with disease severity. Hypocholesterolism is associated with hypocortisolism. The concentrations of total cholesterol and lipoproteins steadily increase after 24 hrs in survivors and are normalized 1–3 months after pediatric intensive care unit admission.

Improved survival of children with sepsis and purpura: effects of age, gender, and era

BackgroundTo gain insight into factors that might affect results of future case-control studies, we performed an analysis of children with sepsis and purpura admitted to the paediatric intensive care unit (PICU) of Erasmus MC-Sophia Childrens Hospital (Rotterdam, The Netherlands).MethodsBetween 1988 and 2006, all 287 children consecutively admitted with sepsis and purpura were included in various sepsis studies. Data regarding age, gender, ethnicity, serogroup of Neisseria meningitidis, severity, therapy, and survival were collected prospectively. These data were pooled into one database and analyzed retrospectively.ResultsThe case fatality rate (CFR) from sepsis and purpura was 15.7%. During the study period, survival improved significantly. Younger age was significantly associated with more severe disease and a higher CFR. Children under the median age of 3.0 years had an increased risk of case fatality (odds ratio 4.3, 95% confidence interval 2.1 to 9.2; p < 0.001). Gender was not associated with CFR. However, males did have higher Paediatric Risk of Mortality scores, fewer PICU-free days, and more presence of shock. The course of sepsis and purpura was not related to ethnic origin. A causative organism was isolated in 84.3% of cases. N. meningitidis was the major organism (97.5%). Although N. meningitidis serogroup B was observed more often in younger children, serogroups were not associated with severity or survival. During the study period, the use of inotropic agents and corticosteroids changed substantially (less dopamine and more dobutamine, norepinephrine, and corticosteroids).ConclusionAge and gender are determinants of severity of paediatric sepsis and purpura. Survival rates have improved during the last two decades.