INFLAMMATORY MARKERS OF OUTCOME

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 diffe rent patterns of pulmonary inflammation, and 2) whether indirect measu rements truly reflect the inflammatory milieu within the lung. Both as sumptions remain unproved. Bronchoalveolar lavage (BAL) directly sampl es the alveolar milieu and is a potential tool for defining both the p ulmonary mediator profile, and to validate plasma mediator concentrati ons. BAL fluid (BALF) eosinophil cationic protein (ECP) concentrations accurately reflect pulmonary eosinophil activation, and the BALF inte rleukin-2 to interleukin-4 ratio may be helpful in defining those chil dren with established pulmonary sensitization to allergen. Of the medi ators 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 t he plasma concentrations of eosinophil-specific mediators. The profile of adhesion molecules in the plasma (e.g. soluble intercellular adhes ion molecule-1, soluble vascular cell adhesion molecule-1 and E-select ion) reflects transmigration of specific types of leucocytes across th e pulmonary endothelium. To date, the potential of this group of solub le markers to define the nature of pulmonary inflammation is unclear. More information is therefore required on pulmonary inflammation in ea rly childhood to guide the future use of plasma markers.