Neutrophil but not eosinophil inflammation is related to the severity of a first acute epidemic bronchiolitis in young infants

Abstract

Acute bronchiolitis is the main cause of emergency visits and hospitalizations in infants. Recent data suggest that neutrophil- and eosinophil-mediated inflammations were part of bronchiolitis pathophysiology. Apart from the defined risk factors, few was known on the underlying pathophysiology, which might point out the differences observed in the severity of the disease. The aim of this study was to assess whether the clinical severity of acute epidemic bronchiolitis in young infants might be related to a specific underlying inflammatory process. Total and differential cell counts, IL-8, eotaxin, eosinophil cationic protein (ECP) and albumin levels were assessed at the time of admission in bronchial secretions from 37 infants (median age 17 wk) with acute bronchiolitis. Outcome severity variables were: hypoxemia, Silverman score, tachypnea, feeding alteration, and duration of hospitalization. Neutrophils predominated, and eosinophils were present in 54% of the infants. IL-8 levels strongly correlated with ECP and albumin levels. Albumin levels were correlated with ECP and eotaxin levels. IL-8 levels were higher in infants with hypoxemia and inversely related with SaO(2) levels. IL-8 and albumin levels significantly rose with respiratory rate, and Silverman score. IL-8, albumin and ECP levels were significantly higher in infants hospitalized >/=7 days. Furthermore, IL-8 levels were correlated with the duration of hospitalization. Neither cell counts nor eotaxin levels were related to the severity criteria studied. This study suggests that IL-8-associated airway inflammation significantly contributed to the severity of acute epidemic bronchiolitis.

Randomized trial to evaluate azithromycin's effects on serum and upper airway IL-8 levels and recurrent wheezing in infants with respiratory syncytial virus bronchiolitis

“…Therefore, there is a need to identify other pharmacological interventions that could be used in children hospitalized with RSV bronchiolitis that may prevent subsequent recurrent wheezing. Conventional asthma controller medications have shown to have limited to no efficacy for the prevention of post-RSV recurrent wheezing 13–20 , possibly related to their limited effect on neutrophilic airway inflammation that predominate the inflammatory process during viral bronchiolitis 22, 23, 34 . Therefore, a medication with anti-neutrophilic properties has the mechanistic rationale to serve as an intervention for the prevention of post-RSV recurrent wheezing.…”

“…Numerous trials using treatments typically used for asthma, such as inhaled corticosteroids (ICS) 13–15 , systemic corticosteroids 16–18 , and montelukast 19, 20 have shown to have limited to no effect on the occurrence of post-bronchiolitis wheezing. These medications have minimal effect on non-eosinophilic airway inflammation 21 , the dominant pattern seen during bronchiolitis 22, 23 , and this may explain lack of efficacy of these treatments on post-bronchiolitis wheezing.…”

Pneumovirus-Induced Lung Disease in Mice Is Independent of Neutrophil-Driven Inflammation

“…Strong lung neutrophil recruitment is also observed in animal pneumovirus disease, such as bovine RSV infection in calves and pneumonia virus of mice (PVM) in rodents [7]. Both human and animal pneumovirus infections elicit prominent CXC chemokine responses, including CXCL-8 [8, 9] and KC [10], which likely contribute to the neutrophilic inflammation. However, so far it is unknown if these high numbers of neutrophils in the airways and lungs are solely protective or may also be detrimental during pneumovirus infections.…”

Nasopharyngeal gene expression, a novel approach to study the course of respiratory syncytial virus infection

“…Current clinical prediction rules are based on demographic criteria and clinical symptoms [3][4][5][6][7][8][9][10] and although they may improve clinical judgement [7,8], they are not routinely used in daily practice. More objective and reproducible predictions may be achieved by using biomarkers [11][12][13][14][15].…”