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Inflammatory markers of outcome
Insights
Early childhood wheezing often lacks atopy-induced inflammation, questioning adult studies. New research explores inflammatory markers in young children to better understand diverse wheezing causes.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Biomarker Research
Background:
- A significant portion of early childhood wheezing may not stem from atopy-induced pulmonary inflammation.
- Existing mediator studies in adults and older children might not be applicable to the unique physiology of young children.
- The utility of inflammatory markers in young children hinges on distinct inflammation patterns in atopic versus nonatopic wheezing and the accuracy of indirect measurements.
Purpose of the Study:
- To investigate the relationship between atopic status and pulmonary inflammation patterns in early childhood wheezing.
- To assess the validity of indirect plasma-based inflammatory markers for reflecting the lung's inflammatory environment.
- To explore the potential of bronchoalveolar lavage (BAL) and specific plasma mediators in characterizing childhood wheezing.
Main Methods:
- Utilized bronchoalveolar lavage (BAL) to directly sample the alveolar milieu for mediator profiling.
- Measured eosinophil cationic protein (ECP) concentrations in BAL fluid (BALF) to assess pulmonary eosinophil activation.
- Analyzed BALF interleukin-2 to interleukin-4 ratio for identifying pulmonary sensitization.
- Correlated plasma concentrations of eosinophil-specific mediators (ECP, eosinophil protein X [EPX], major basic protein [MBP]) and adhesion molecules with atopy-induced wheezing.
Main Results:
- BALF ECP concentrations accurately reflect pulmonary eosinophil activation.
- The BALF interleukin-2 to interleukin-4 ratio may help identify children with established pulmonary sensitization.
- Plasma ECP, EPX, and MBP correlate with atopy-induced wheezing, but systemic atopic activation can also elevate these markers.
- The diagnostic potential of plasma adhesion molecules (e.g., soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, E-selectin) for defining pulmonary inflammation remains unclear.
Conclusions:
- Bronchoalveolar lavage is a valuable tool for assessing pulmonary inflammation and validating plasma markers in young children.
- Specific BALF mediators can help differentiate types of wheezing and identify sensitization.
- Further research is needed to clarify the role of plasma markers, including adhesion molecules, in characterizing early childhood pulmonary inflammation.
Abstract:
A significant proportion of early childhood wheezing appears not to be due to atopy-induced pulmonary inflammation, and mediator studies in atopic adults and older children may not be relevant to this age group. The usefulness of inflammatory markers in young children is related to 1) whether atopic and nonatopic wheezing are associated with different patterns of pulmonary inflammation, and 2) whether indirect measurements truly reflect the inflammatory milieu within the lung. Both assumptions remain unproved. Bronchoalveolar lavage (BAL) directly samples the alveolar milieu and is a potential tool for defining both the pulmonary mediator profile, and to validate plasma mediator concentrations. BAL fluid (BALF) eosinophil cationic protein (ECP) concentrations accurately reflect pulmonary eosinophil activation, and the BALF interleukin-2 to interleukin-4 ratio may be helpful in defining those children with established pulmonary sensitization to allergen. Of the mediators that have been measured in the plasma, ECP eosinophil protein X (EPX) and major basic protein (MBP) correlate well with atopy-induced wheezing. However atopic activation in other sites may also increase the plasma concentrations of eosinophil-specific mediators. The profile of adhesion molecules in the plasma (e.g. soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1 and E-selection) reflects transmigration of specific types of leucocytes across the pulmonary endothelium. To date, the potential of this group of soluble markers to define the nature of pulmonary inflammation is unclear. More information is therefore required on pulmonary inflammation in early childhood to guide the future use of plasma markers.