Background and objective: The soluble receptor for advanced glycation end products (sRAGE) plays an important role in inflammation. Few studies have looked at sRAGE levels in human lungs, and there is no information in children. Therefore, this study aimed to compare bronchoalveolar lavage fluid (BALF) and plasma sRAGE concentrations in children in relation to age and inflammation.
Methods: BAL was performed in 76 children, and BALF and plasma sRAGE levels were determined by enzyme-linked immunosorbent assay.
Results: sRAGE levels were fourfold higher in BALF than in plasma (P < 0.001). BALF sRAGE was inversely proportional to age (r = −0.333, P = 0.008) and serum immunoglobulin A (r = −0.283, P = 0.028). Plasma sRAGE showed a positive correlation to the percentage of BAL macrophages and negative correlation to the percentage of neutrophils and lymphocytes (P < 0.05). Multivariate linear regression analysis identified that the percentage of BAL lymphocytes and neutrophils were significant independent predictors of plasma sRAGE levels, while age and the percentage of BAL macrophages independently predicted BALF sRAGE levels.
Conclusions: In children, sRAGE is present at higher concentrations in the lung compared with blood. It appears that sRAGE varies with age, and hence future studies of sRAGE in paediatric lung disease require age matching. The significant relationship between sRAGE and lung inflammation warrants further research.