Procalcitonin as a prognostic marker in meningococcal disease.

OBJECTIVE: To assess the prognostic value of procalcitonin levels during the clinical course of meningococcal disease in children. DESIGN: A retrospective, descriptive study. SETTING: University paediatric intensive care unit. PATIENTS: Nine patients with meningococcal sepsis and 55 patients with meningococcal septic shock were included in the study, giving a total of 64. MEASUREMENTS AND RESULTS: Procalcitonin (PCT), C-reactive protein (CRP), cytokines (IL-6, IL-8 and TNF-alpha), plasminogen activator inhibitor-1 (PAI-1) and several routine laboratory parameters were determined and expressed as medians (ranges). PCT levels on hospitalisation were elevated in all children as compared to normal values. Median PCT levels on admission were significantly higher in children with septic shock than in children with sepsis (270 ng/ml (5.7-672.3) versus 64.4 (20.6-283.7); p<0.01). When the patients were categorised to severity using the Pediatric Risk of Mortality (PRISM) score (group 1: <15 points, group 2: 16-30, group 3: >30), the PCT levels were significantly different in the three groups. All markers, with the exception of PCT (p=0.056), were significantly different between survivors and non-survivors. When the duration of petechiae was taken into account, the difference in PCT levels became significant (p=0.04). CONCLUSIONS: Procalcitonin levels on admission are related to severity. In the case of a short disease history (duration of petechiae), PCT levels are also related to mortality. Although PCT levels are elevated in all patients, the levels per se do not allow a prediction about survival versus non-survival, this is in contrast to other markers and scores (PRISM).

Acute stress response in children with meningococcal sepsis: important differences in the growth hormone/insulin-like growth factor I axis between nonsurvivors and survivors.

Septic shock is the most severe clinical manifestation of meningococcal disease and is predominantly seen in children under 5 yr of age. Very limited research has been performed to elucidate the alterations of the GH/IGF-I axis in critically ill children. We evaluated the GH/IGF-I axis and the levels of IGF-binding proteins (IGFBPs), IGFBP-3 protease, glucose, insulin, and cytokines in 27 children with severe septic shock due to meningococcal sepsis during the first 3 d after admission. The median age was 22 months (range, 4-185 months). Eight patients died. Nonsurvivors had extremely high GH levels that were significant different compared with mean GH levels in survivors during a 6-h GH profile (131 vs. 7 mU/liter; P < 0.01). Significant differences were found between nonsurvivors and survivors for the levels of total IGF-I (2.6 vs. 5.6 nmol/liter), free IGF-I (0.003 vs. 0.012 nmol/liter), IGFBP-1 (44.3 vs. 8.9 nmol/liter), IGFBP-3 protease activity (61 vs. 32%), IL-6 (1200 vs. 50 ng/ml), and TNFalpha (34 vs. 5.3 pg/ml; P < 0.01). The pediatric risk of mortality score correlated significantly with levels of IGFBP-1, IGFBP-3 protease activity, IL-6, and TNFalpha (r = +0.45 to +0.69) and with levels of total IGF-I and free IGF-I (r = -0.44 and -0.55, respectively). Follow-up after 48 h in survivors showed an increased number of GH peaks, increased free IGF-I and IGFBP-3 levels, and lower IGFBP-1 levels compared with admission values. GH levels and IGFBP-1 levels were extremely elevated in nonsurvivors, whereas total and free IGF-I levels were markedly decreased and were accompanied by high levels of the cytokines IL-6 and TNFalpha. These values were different from those for the survivors. Based on these findings and literature data a hypothetical model was constructed summarizing our current knowledge and understanding of the various mechanisms.

Prevention of meningococcal serogroup B infections in children: a protein-based vaccine induces immunologic memory.

Immunologic memory against meningococci was studied in 177 children (100 children were 10-11 years old and 77 were 5-6 years old) 2.5 years after vaccination with hexavalent meningococcal outer membrane vesicle (OMV) vaccine or hepatitis B (HepB) vaccine. Children were revaccinated with monovalent P1.7(h),4 meningococcal OMV vaccine. Serum bactericidal antibodies (SBAs) were measured before revaccination and after 4-6 weeks. A minimum 4-fold increase in SBAs against serosubtype P1.7(h),4 was detected in 48.5% of the children after hexavalent meningococcal vaccine and in 8.9% after HepB vaccine. Of the initial responders given hexavalent meningococcal vaccine, 78% had > or =4-fold increase in SBAs against strain P1.4. Thus, immunologic memory is present in toddlers and school-aged children previously given 3 hexavalent meningococcal vaccinations. Booster vaccination with monovalent P1.7(h),4 meningococcal OMV vaccine induces a significant increase in SBAs against serosubtype P1.7(h),4 and cross-reactivity against other serosubtypes in the hexavalent vaccine.

Endocrine and metabolic responses in children with meningoccocal sepsis: striking differences between survivors and nonsurvivors.

To get insight in the endocrine and metabolic responses in children with meningococcal sepsis 26 children were studied the first 48 h after admission. On admission there was a significant difference in cortisol/ACTH levels between nonsurvivors (n = 8) and survivors (n = 18). Nonsurvivors showed an inadequate cortisol stress response in combination to very high ACTH levels, whereas survivors showed a normal stress response with significantly higher cortisol levels (0.62 vs. 0.89 micromol/L) in combination with moderately increased ACTH levels (1234 vs. 231 ng/L). Furthermore, there was a significant difference between nonsurvivors and survivors regarding pediatric risk of mortality score (31 vs. 17), TSH (0.97 vs. 0.29 mE/L), T3 (0.53 vs. 0.38 nmol/L), reverse T3 (rT3) (0.75 vs. 1.44 nmol/L), C-reactive protein (34 vs. 78 mg/L), nonesterified fatty acids (0.32 vs. 0.95 mmol/L), and lactate (7.3 vs. 3.2 mmol/L). In those who survived, the most important changes within 48 h were seen in a normalization of cortisol and ACTH levels, but without a circadian rhythm; a decrease of rT3 and an increase in the T3/rT3 ratio; and a decrease in the levels of the nonesterified free fatty acids and an unaltered high urinary nitrogen excretion. At this moment, it is yet unknown whether the hormonal abnormalities are determining factors in the outcome of acute meningococcal sepsis or merely represent secondary effects. Understanding the metabolic and endocrine alterations is required to design possible therapeutic approaches. The striking difference between nonsurvivors and survivors calls for reconsideration of corticosteroid treatment in children with meningococcal sepsis.

Immunogenicity and safety of a hexavalent meningococcal outer-membrane-vesicle vaccine in children of 2-3 and 7-8 years of age.

To study the reactogenicity and immunogenicity of a hexavalent meningococcal outer-membrane-vesicle vaccine (OMV), two different dosages of this vaccine (7.5 and 15 microg of individual PorA proteins) consisting of vesicles expressing class 1 outer-membrane proteins (OMPs) of subtypes P1.7,16; P1.5,2; P1.19,15 and P1.5(c), 10; P1.12,13; P1.7(h),4 were administered to a group of 7-8 year (n=165) and a group of 2-3 year old children (n=172). Control groups of children with similar ages were vaccinated against hepatitis B. All participants received three injections. Pre- and postimmunisation sera were tested for bactericidal antibodies against six isogenic meningococcal vaccine strains expressing different PorA proteins. Antibody titres against OMP of the two different vesicles (PL16215 and PL10124) were measured by ELISA. The meningococcal hexavalent OMV vaccine was well tolerated. No statistically significant differences were seen between the high and low dose of hexavalent meningococcal OMV vaccine. The percentage of children showing a fourfold increase of bactericidal antibody titres against the specific serosubtype varied in toddlers from 28 to 98% and in older children from 16 to 100%. Both ELISA antibody titres and bactericidal activity showed the highest level in the youngest age-group.

Immunogenicity and safety of monovalent p1.7(h),4 meningococcal outer membrane vesicle vaccine in toddlers: comparison of two vaccination schedules and two vaccine formulations.

The safety and immunogenicity of two PorA-based meningococcal outer membrane vesicle (OMV) vaccines against the P1.4 serosubtype adsorbed with AlPO(4) or Al(OH)(3) were studied in 134 toddlers. Vaccinations were given three times with an interval of 3-6 weeks or twice with an interval of 6-10 weeks. A vaccination was repeated after 20-40 weeks. Pre- and post-immunization sera were tested for bactericidal activity against an isogenic strain expressing P1.7(h), 4 PorA. Both meningococcal OMV vaccines were well tolerated. The percentage of children with a fourfold increase in bactericidal activity was 96% (AlPO(4)-adjuvated vaccine/2+1 schedule), 100% (AlPO(4)-adjuvated vaccine/3+1 schedule), 93% (Al(OH)(3)-adjuvated vaccine/2+1 schedule) and 97% (Al(OH)(3)-adjuvated vaccine/3+1 schedule). Adsorption with AlPO(4) makes the OMV vaccine more immunogenic than adsorption with Al(OH)(3). Bactericidal activity was highest after the 3+1 schedule, although the response shortly after the primary series was higher in the two-dose priming group.

Pathophysiology of meningococcal sepsis in children.

UNLABELLED: Septic shock with purpura is a syndrome frequently diagnosed in children and predominantly caused by Neisseria meningitidis. Despite improvements in management and therapy the mortality and morbidity in these patients are still high. During the last few years much effort has been put into understanding of the systemic host response during this acute infectious disease. This host response can be divided into the process of recognition of endotoxin, the cascade of pro- and counter inflammatory mediators, the endothelial damage resulting in capillary leakage and inappropriate vascular tone, and the procoagulant state. CONCLUSION: This paper reviews the recent insights in the pathophysiology of the host response and their possible consequences for novel therapies in meningococcal sepsis.