Aim:To examine over time, the cellular response within the lungs of infants ventilated with respiratory syncytial virus (RSV) bronchiolitis and to compare this response in infants born at term with those born preterm. Methods: Non-bronchoscopic bronchoalveolar lavage (BAL) samples were taken from 47 infants (24 born at term and 23 born preterm) who were ventilated for RSV positive bronchiolitis and 10 control infants. BAL cellularity and differential cell counts were calculated using standard techniques. Results: Total cellularity in BAL over the first four days of ventilation in infants with RSV bronchiolitis was greater in term infants (median 2.2 (IQR 4.27) × 10 6 cells/ml) compared with preterm infants (0.58 (1.28) × 10 6 cells/ml). The magnitude of the cellular response in preterm infants with bronchiolitis was similar to that in the control group measured on day 1 (0.62 (0.77) × 10 6 cells/ml). BAL cellularity decreased progressively from the time of intubation in term infants, but remained relatively constant in preterm infants up to seven days after intubation. Conclusions: There are differences in the magnitude and type of pulmonary cellular response in term and preterm infants ventilated with RSV bronchiolitis. The cellular response in term infants with bronchiolitis differs from that in a control group of infants. These differences may reflect variations in cellular recruitment in the lung and/or variations in airway calibre.

Respiratory syncytial virus (RSV) bronchiolitis is an important cause of severe respiratory disease in infants. This study aimed to characterise changes in pulmonary pro-and anti-inflammatory responses in infants with RSV bronchiolitis over the course of the illness.On the day of intubation (Day 1) and the day of extubation (Day X), nonbronchoscopic bronchoalveolar lavage was performed on term and preterm infants ventilated for RSV bronchiolitis and on control infants on Day 1. Tumour necrosis factor (TNF)-a, soluble TNF receptor (sTNFR) and interleukin (IL)-6 messenger ribonucleic acid (mRNA) and protein were measured.Twenty-four infants, born at term and 23 infants born preterm with RSV bronchiolitis and 10 controls were recruited. TNF-a and IL-6 mRNA and protein in infants with bronchiolitis were greater than the control group on Day 1. In preterm infants, who were ventilated for longer than term infants, TNF-a and IL-6 proteins decreased between Day 1 and Day X. Concentrations of sTNFRs differed between groups on Day 1, but levels did not change between Day 1 and Day X.Large amounts of tumour necrosis factor-a and interleukin-6 in the respiratory syncytial virus-infected lung suggest important roles for these cytokines in the pathogenesis of respiratory syncytial virus bronchiolitis. The decrease in tumour necrosis factor-a and interleukin-6 protein in preterm infants may reflect the prolonged clinical course seen in these infants.

During the initial phase of meningococcal disease, raised cortisol and ACTH levels indicate an appropriate stress response within the hypothalamic-pituitary-adrenal axis. However, a substantial subpopulation (11 [16.9%] of 65) has evidence of adrenal dysfunction during this period. Morning cortisol values in the initial phase of meningococcal disease could be used as a potential early index of AI.

No abstract