Prospective observational study in two Dutch hospitals to assess the performance of inflammatory plasma markers to determine disease severity of viral respiratory tract infections in children.

INTRODUCTION: Respiratory viruses causing lower respiratory tract infections (LRTIs) are a major cause of hospital admissions in children. Since the course of these infections is unpredictable with potential fast deterioration into respiratory failure, infants are easily admitted to the hospital for observation. The aim of this study was to examine whether systemic inflammatory markers can be used to predict severity of disease in children with respiratory viral infections. METHODS: Blood and nasopharyngeal washings from children <3 years of age with viral LRTI attending a hospital were collected within 24 hours (acute) and after 4-6 weeks (recovery). Patients were assigned to a mild (observation only), moderate (supplemental oxygen and/or nasogastric feeding) or severe (mechanical ventilation) group. Linear regression analysis was used to design a prediction rule using plasma levels of C reactive protein (CRP), serum amyloid A (SAA), pentraxin 3 (PTX3), serum amyloid P component and properdin. This rule was tested in a validation cohort. RESULTS: One hundred and four children (52% male) were included. A combination of CRP, SAA, PTX3 and properdin was a better indicator of severe disease compared with any of the individual makers and age (69% sensitivity (95% CI 50 to 83), 90% specificity (95% CI 80 to 96)). Validation in 141 patients resulted in 71% sensitivity (95% CI 53 to 85), 87% specificity (95% CI 79 to 92), negative predictive value of 64% (95% CI 47 to 78) and positive predictive value of 90% (95% CI 82 to 95). The prediction rule was not able to identify patients with a mild course of disease. CONCLUSION: A combination of CRP, SAA, PTX3 and properdin was able to identify children with a severe course of viral LRTI disease, even in children under 2 months of age. To assess the true impact on clinical management, these results should be validated in a prospective randomised control study.

CD4+ T-cell counts and interleukin-8 and CCL-5 plasma concentrations discriminate disease severity in children with RSV infection.

BACKGROUND: Current tools to predict the severity of respiratory syncytial virus (RSV) infection might be improved by including immunological parameters. We hypothesized that a combination of inflammatory markers would differentiate between severe and mild disease in RSV-infected children. METHODS: Blood and nasopharyngeal samples from 52 RSV-infected children were collected during acute infection and after recovery. Retrospectively, patients were categorized into three groups based on disease severity: mild (no supportive treatment), moderate (supplemental oxygen and/or nasogastric feeding), and severe (mechanical ventilation). Clinical data, number of flow-defined leukocyte subsets, and cytokine concentrations were compared. RESULTS: Children with severe RSV infection were characterized by young age; lymphocytopenia; increased interleukin (IL)-8, granulocyte colony-stimulating factor (G-CSF), and IL-6 concentrations; and decreased chemokine (C-C motif) ligand (CCL-5) concentrations in plasma. The combination of plasma levels of IL-8 and CCL-5, and CD4+ T-cell counts, with cutoff values of 67 pg/ml, 13 ng/ml, and 2.3 × 10(6)/ml, respectively, discriminated severe from mild RSV infection with 82% sensitivity and 96% specificity. CONCLUSION: This study demonstrates that the combination of CD4+ T-cell counts and IL-8 and CCL-5 plasma concentrations correlates with disease severity in RSV-infected children. In addition to clinical features, these immunological markers may be used to assess severity of RSV infection and guide clinical management.

Fatal coronary artery disease in an infant with severe mucopolysaccharidosis type I.

A previously healthy 10-month-old boy was referred to our hospital because of coarse facial features that were suggestive of lysosomal storage disease. Apart from noisy respiration, there was no medical history. Elevated levels of urinary glycosaminoglycans and complete deficiency of leukocyte α-l-iduronidase indicated severe mucopolysaccharidosis type I. A chest radiograph revealed a markedly enlarged heart, and echocardiography revealed hypertrophic cardiomyopathy. While hematopoietic stem cell transplantation was being planned, progressive cardiac failure developed with a striking hypokinesia of the left-ventricle free wall. In combination with ischemic changes on the electrocardiogram, this was suggestive of coronary artery disease. Results of coronary echo Doppler interrogation were inconclusive, and intravascular ultrasound in this little infant was not feasible. Despite the patient's small size, a successful selective coronary angiography was performed and revealed diffuse narrowing of the left coronary artery with collateral flow from the right coronary artery. Enzyme-replacement therapy was started immediately in an attempt to improve myocardial performance. Evaluation after 3 months, however, revealed complete obliteration of the left coronary main stem with diffuse hypokinesia/akinesia of the left ventricle. At the age of 13 months the boy died of terminal cardiac failure. This case report illustrates the importance of considering early development of coronary artery disease in children with severe mucopolysaccharidosis type I and cardiomyopathy.

A single recruitment maneuver in ventilated critically ill children can translocate pulmonary cytokines into the circulation.

INTRODUCTION: Recruitment maneuvers (RMs) are advocated to prevent pulmonary collapse during low tidal volume ventilation and improve oxygenation. However, convincing clinical evidence for improved outcome is lacking. Recent experimental studies demonstrate that RMs translocate pulmonary inflammatory mediators into the circulation. To determine whether a single RM in ventilated children affects pulmonary and systemic cytokine levels, we performed a prospective intervention study. METHODS: Cardiorespiratory stable ventilated patients (0.5-45 months, n = 7) with acute lung injury were subjected to an RM determining opening and closing pressures (peak inspiratory pressure < or =45 cmH(2)O, positive end expiratory pressure (PEEP) < or =30 cmH(2)O). Before and after RM, cardiorespiratory parameters and ventilator settings were recorded, blood gas analysis performed, and bronchoalveolar lavage fluid and plasma TNF-alpha, IL-1beta, IL-6, IL-8, and IL-10 concentrations were determined. RESULTS: Fifteen minutes after the RM, an increase was observed in plasma tumor necrosis factor-alpha (400% +/- 390% of baseline, P = .04), IL-6 (120% +/- 35%, P = .08), and IL-1beta (520% +/- 535%, P = .04), which decreased at T = 60 minutes, hence indicative of translocation. Recruitment maneuver did not change the plasma levels of the anti-inflammatory IL-10 (105% +/- 12%, P = .5). Apart from a nonsignificant increase of IL-8 after 360 minutes (415% +/- 590%,P = .1), bronchoalveolar cytokine levels were not influenced by the RM. No increase in oxygenation or improvement of lung kinetics was observed. CONCLUSIONS: A single RM can translocate pro-inflammatory cytokines from the alveolar space into the systemic circulation in ventilated critically ill children.

Mannose-binding lectin is a critical factor in systemic complement activation during meningococcal septic shock.

BACKGROUND: Systemic activation of complement during meningococcal disease is associated with severe disease and poor outcome. The exact mechanism of activation of complement is unknown but is important for future therapies aimed at modulating the complement system in this disease. METHODS: We studied complement activation in a group of 22 patients, including 18 with meningococcal septic shock and 4 with meningococcal disease without shock. Two of the patients with shock were MBL deficient: 1 patient was homozygous and 1 patient was compound heterozygous for exon 1 mutations in the gene for MBL. RESULTS: The MBL-deficient patients had relatively low disease severity and mild disseminated intravascular coagulation (DIC). At admission to the pediatric intensive care unit, the MBL-deficient patients had much lower circulating values of C3bc (indicating common pathway activation) and terminal complement complex (indicating terminal pathway activation) than did MBL-sufficient patients who presented with meningococcal septic shock. Levels of C4bc (indicating classical or lectin pathway activation) and C3bBbP (indicating alternative pathway activation) were also decreased in the MBL-deficient patients. Systemic activation of complement excellently correlated with disease severity and parameters of DIC. Testing of convalescent blood samples from 1 of the MBL-deficient patients in a model of meningococcal sepsis showed that a lack of lectin pathway activation leads to a reduced activation of complement. CONCLUSIONS: This indicates that MBL is critical for the systemic activation of complement seen during meningococcal septic shock.

Influence of innate cytokine production capacity on clinical manifestation and severity of pediatric meningococcal disease.

OBJECTIVE: To analyze the role of the innate production capacity for tumor necrosis factor, interleukin-1beta, interleukin-12, and interleukin-10 in the clinical presentation and severity of meningococcal disease. DESIGN: Whole blood cultures from survivors of severe meningococcal disease obtained median 5.4 yrs after hospitalization were stimulated with meningococcal lipopolysaccharide and heat-killed Neisseria meningitidis bacteria. SETTING: Intensive care unit in academic hospital. PATIENTS: A total of 111 children were included. We classified these patients according to clinical manifestation in four groups: shock (n = 43); both shock and meningitis (n = 11); bacteremia (neither shock nor meningitis, n = 24); and distinct meningitis (n = 33). INTERVENTIONS: : None. MEASUREMENTS AND MAIN RESULTS: The classification into four groups stratifies these patients according to disease severity. No differences in whole blood cytokine production were found between the patients in these four groups. However, within the group of patients who had presented with shock, interleukin-1beta and the interleukin-1beta/interleukin-10 ratio were negatively correlated with disease severity (R = -.35, p = .03 and R = -.33, p = .04, respectively; Pediatric Risk of Mortality score). CONCLUSIONS: Clinical manifestation of meningococcal disease cannot be explained by the innate production capacity of whole blood cultures for the cytokines tumor necrosis factor, interleukin-1beta, interleukin-10, and interleukin-12. In patients who presented with shock, a low production capacity for interleukin-1beta and a low interleukin-1beta/interleukin-10 production ratio was associated with more severe disease.

Pentraxin 3 and C-reactive protein in severe meningococcal disease.

The long pentraxin 3 (PTX3) is an important element of the innate immune system and has potential as a diagnostic tool in inflammatory conditions. We studied PTX3 in patients admitted to an intensive care unit with severe meningococcal disease and compared it with the short pentraxin C-reactive protein (CRP). Twenty-six patients with meningococcal disease were studied, 17 patients presented with meningococcal septic shock (shock group), and 9 patients presented with meningococcal meningitis or bacteremia (no-shock group). Pentraxin 3 and CRP were measured by enzyme-linked immunosorbent assay. High plasma concentrations of PTX3 (median, 579 microg/L) were seen at admission in patients with meningococcal disease. Concentrations were significantly higher in patients with shock compared with patients without shock (medians, 801 and 256 microg/L, respectively; P = 0.006). In contrast, CRP at admission was lower in the shock group as compared with the no-shock group (medians, 58 and 165 mg/L, respectively; P = 0.008). High PTX3 and low CRP concentration at admission discriminated between presence and absence of shock (area under the receiver operating characteristic curve, 0.85; P = 0.007 for PTX3 and area under the receiver operating characteristic curve, 0.84; P = 0.01 for CRP). PTX3 did not correlate with disease severity (pediatric risk of mortality) and days spent in the intensive care unit. PTX3 at admission and PTX3 peak concentration both showed a negative correlation with plasma fibrinogen concentrations. C-reactive protein concentration at admission correlated negatively with disease severity. In conclusion, PTX3 was an early indicator of shock in patients with severe meningococcal disease that followed a pattern of induction distinct from CRP.

Macrophage migration inhibitory factor (MIF) in meningococcal septic shock and experimental human endotoxemia.

Macrophage migration inhibitory factor (MIF) is a mediator of innate immunity and important in the pathogenesis of septic shock. Lipopolysaccharide (LPS) and tumor necrosis factor (TNF) alpha are reported to be inducers of MIF. We studied MIF and cytokines in vivo in patients with meningococcal disease, in human experimental endotoxemia, and in whole blood cultures using a newly developed sensitive and specific enzyme-linked immunosorbent assay. Twenty patients with meningococcal disease were investigated. For the human endotoxemia model, 8 healthy volunteers were intravenously injected with 2 ng/kg Escherichia coli LPS. Whole blood from healthy volunteers was incubated with LPS or heat-killed meningococci. Macrophage migration inhibitory factor concentration in blood was increased during meningococcal disease and highest in the patients presenting with shock compared with patients without shock. Plasma concentration of MIF correlated with disease severity, the presence of shock and with the cytokines interleukin (IL) 1beta, IL-10, IL-12, and vascular endothelial growth factor, but not with TNF-alpha. MIF was not detected in blood in experimental endotoxemia, nor after stimulation of whole blood with LPS or meningococci, although high levels of TNF-alpha were seen in both models. In conclusion, MIF is increased in patients with meningococcal disease and highest in the presence of shock. Macrophage migration inhibitory factor cannot be detected in a human endotoxemia model and is not produced by whole blood cells incubated with LPS or meningococci.

Cardiac resynchronization therapy for mitral systolic anterior motion in a child.

We describe the successful use of cardiac resynchronization therapy for treatment of mitral valve systolic anterior motion with left ventricle outflow tract obstruction after re-excision of a subaortic membrane and septal myectomy in a 12-year-old child. In the recovery phase, a total atrioventricular block persisted. Therefore a permanent atrioventricular pacing system was implanted.

Deficient alternative complement pathway activation due to factor D deficiency by 2 novel mutations in the complement factor D gene in a family with meningococcal infections.

The complement system is an essential element in our innate defense against infections with Neisseria meningitidis. We describe 2 cases of meningococcal septic shock, 1 of them fatal, in 2 children of a Turkish family. In the surviving patient, alternative pathway activation was absent and factor D plasma concentrations were undetectable. Concentrations of mannose-binding lectin (MBL), C1q, C4 and C3, factor B, properdin, factor H, and factor I were normal. Mutation analysis of the factor D gene revealed a T638 > G (Val213 > Gly) and a T640 > C (Cys214 > Arg) mutation in the genomic DNA from the patient, both in homozygous form. The consanguineous parents and an unaffected sister had these mutations in heterozygous form. In vitro incubation of factor-D-deficient plasma of the boy with serogroup B N meningitidis showed normal MBL-mediated complement activation but no formation of the alternative pathway C3-convertase C3bBbP, and severely decreased C3bc formation and terminal complement activation. The defect was restored after supplementation with factor D. In conclusion, this is the second report of a factor D gene mutation leading to factor D deficiency in a family with meningococcal disease. This deficiency abolishes alternative-pathway dependent complement activation by N meningitidis, and leads to an increased susceptibility to invasive meningococcal disease.

Pneumolysin is a key factor in misidentification of macrolide-resistant Streptococcus pneumoniae and is a putative virulence factor of S. mitis and other streptococci.

We evaluated the applicability of ply PCR for confirmation of the identification of Streptococcus pneumoniae. lytA PCR, 16S rRNA sequencing, and amplified-fragment length polymorphism were used as reference methods. In contrast to the lytA gene, the ply gene proved to be not specific for S. pneumoniae. The presence of the ply gene in other streptococci, in particular Streptococcus mitis, suggests that pneumolysin plays a pathogenic role.

Amplified fragment length polymorphism fingerprinting is an effective technique to distinguish streptococcus pneumoniae from other Streptococci and an efficient alternative to pulsed-field gel electrophoresis for molecular typing of pneumococci.

Amplified fragment length polymorphism versus pulsed-field gel electrophoresis was used for fingerprinting of 85 macrolide-resistant pneumococcal isolates identified by using primarily phenotypic methods. Confirmation of identification by 16S rRNA sequencing revealed that 27 isolates were actually nonpneumococci. Amplified fragment length polymorphism but not pulsed-field gel electrophoresis offered simultaneous and accurate discrimination between pneumococci and nonpneumococcal species.