Interleukin-4 and interleukin-4 soluble receptor alpha levels in bronchoalveolar lavage from children with asthma.
BACKGROUND
In asthma there is increased expression of the Th2-type cytokine interleukin-4 (IL-4). IL-4 is important in immunoglobulin isotype switching to immunoglobulin E and adhesion of eosinophils to endothelium.


OBJECTIVE
We hypothesized that levels of IL-4 in bronchoalveolar lavage (BAL) fluid would be increased in stable, atopic asthmatic children compared with controls and that levels of its physiologic inhibitor IL-4 soluble receptor alpha (IL-4sR alpha) would be correspondingly decreased.


METHODS
One hundred sixteen children attending a children's hospital for elective surgery were recruited. A nonbronchoscopic BAL was performed, and IL-4 and IL-4sR alpha were measured in the BAL supernatants.


RESULTS
There was no significant difference in IL-4 concentrations between atopic asthmatic children, atopic normal controls, and nonatopic normal controls [0.13 pg/mL (0.13 to 0.87) vs 0.13 pg/mL (0.13 to 0.41) vs 0.13 pg/mL (0.13 to 0.5), P = 0.65]. IL-4sR alpha levels were significantly increased in asthmatic patients compared with atopic controls [6.4 pg/mL (5.0 to 25.5) vs 5.0 pg/mL (5.0 to 9.9), P = 0.018], but not when compared with the nonatopic controls [5.2 pg/mL (5.0 to 10.6), P = 0.19].


CONCLUSIONS
Contrary to expectation, IL-4sR alpha levels are increased in BAL from stable asthmatic children compared with nonatopic controls, and we speculate that IL-4sR alpha is released by inflammatory cells in the airways to limit the proinflammatory effects of IL-4.
Fitch
Patrick S
PS
Department of Clinical Biochemistry, The Queen's University of Belfast, The Institute of Clinical Science, Belfast, Northern Ireland, United Kingdom.
Brown
Vanessa
V
Schock
Bettina C
BC
Ennis
Madeleine
M
Shields
Michael D
MD
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry* / Q000166:cytology; D002452:Cell Count; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis; D007223:Infant; D015847:Interleukin-4 / Q000097:blood*; D008297:Male; D019948:Receptors, Interleukin-4 / Q000097:blood*; D012995:Solubility; D018418:Th2 Cells / Q000378:metabolism
D019948:Receptors, Interleukin-4; D015847:Interleukin-4; D007073:Immunoglobulin E