Urinary eosinophil protein X in children with atopic asthma: a useful marker of antiinflammatory treatment.
BACKGROUND
Bronchial asthma is associated with elevated serum levels of eosinophil products, such as eosinophil protein X (EPX), but the occurrence in urine of this substance in patients with asthma has not previously been studied.


OBJECTIVE
This study was performed to clarify whether increased amounts of eosinophil granulocyte proteins in urine and serum reflect ongoing asthmatic inflammation and whether decreasing values reflect successful treatment.


METHODS
Twelve children with a median age of 12.5 years who had mild or moderate atopic asthma were studied for 3 months. At the time of inclusion in the study, treatment with inhaled budesonide was initiated. Nine children of the same age without atopic disease served as control subjects. Levels of EPX, eosinophil cationic protein (ECP), and myeloperoxidase in serum and in urine (urinary EPX) were determined at inclusion and then after 3 months of treatment. Spirometry was performed on the same occasions.


RESULTS
At the time of inclusion, urinary EPX and serum ECP were significantly higher in children with atopic asthma than in the control subjects (mean, 116.4 vs 43.0 micrograms/mmol creatinine [p = 0.004] and 37.0 vs 14.8 micrograms/L [p = 0.004]). In the asthma group urinary EPX, as well as serum ECP, decreased significantly after 3 months of treatment with budesonide (116.4 to 68.4 micrograms/mmol creatinine [p = 0.005] and 37.0 to 24.0 micrograms/L [p = 0.04]). At the same time, peak expiratory flow values increased significantly in the children with asthma (76.0% to 87.8% of predicted value [p = 0.005]) but not in the control subjects (87.0% to 90.1%). In the asthma group the levels of myeloperoxidase were similar to those in the control group, both at inclusion and after 3 months.


CONCLUSIONS
Increased urinary EPX and serum ECP levels seem to reflect active atopic asthma, whereas decreased levels after antiinflammatory treatment probably reflect normalization of airway inflammation, and indirectly, improved lung function.
Kristjánsson
S
S
Department of Paediatrics, University of Göteborg, Sweden.
Strannegård
I L
IL
Strannegård
O
O
Peterson
C
C
Enander
I
I
Wennergren
G
G
D000293:Adolescent; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000652:urine*; D015415:Biomarkers; D001798:Blood Proteins / Q000378:metabolism / Q000652:urine*; D002648:Child; D047091:Eosinophil Granule Proteins; D047208:Eosinophil-Derived Neurotoxin; D004804:Eosinophils / Q000502:physiology; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D012123:Pulmonary Ventilation; D012260:Ribonucleases
D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D047208:Eosinophil-Derived Neurotoxin; D012260:Ribonucleases