Urinary eosinophil-derived neurotoxin/protein X: a simple method for assessing eosinophil degranulation in vivo.
BACKGROUND
Eosinophil-derived neurotoxin/protein X (EDN/EPX), one of the cationic granule proteins released by polymorphonuclear eosinophils, can be detected in human urine.


OBJECTIVE
We sought to evaluate whether the urinary release of EDN/EPX was dependent on the blood eosinophil cell count, the bronchoalveolar eosinophil cell count, or both and on the clinical diagnosis. We also attempted to determine the precise kinetics of decrease of EDN excretion and eosinophil counts after the onset of corticosteroid treatment.


METHODS
Daily urinary release of EDN/EPX was measured by radioimmunoassay in 28 patients with high hypereosinophilia (group 1), 32 patients with moderate hypereosinophilia (group 2), 26 patients without hypereosinophilia at the time of the study but with a known pulmonary disease involving eosinophils (group 3), and 13 control patients (group 4).


RESULTS
The urinary excretion of EDN/EPX was significantly higher in patients from groups 1 or 2 than in patients from groups 3 or 4. Particularly high levels of EDN/EPX excretion were observed in patients from groups 1 or 2 with chronic eosinophilic pneumonia (chronic eosinophilic pneumonia: 4.7 +/- 8.1 mg/day, control subjects: 0.39 +/- 0.33 mg/day, p < 0.001). Urinary excretion of EDN/EPX was significantly correlated with blood (r = 0.66, p < 0.001) and differential bronchoalveolar (r = 0.62, p = 0.04) eosinophil cell counts in patients from group 1 but not from the other groups. Corticosteroid treatment was followed by a significant decrease in EDN/EPX excretion. The kinetics of decrease in EDN/EPX were delayed as compared with the dramatic drop in peripheral eosinophil counts. Distinct kinetics between urinary EDN/EPX and eosinophil counts differentiated the recurrence of chronic eosinophilic pneumonia from an asthma attack in one patient.


CONCLUSIONS
Measurement of urinary EDN/EPX excretion may be a useful indicator of eosinophil degranulation in vivo.
Cottin
V
V
Service de Pneumologie, Hôpital Cardiovasculaire et Pneumologique Louis Pradel, Université Claude Bernard, Lyon, France.
Deviller
P
P
Tardy
F
F
Cordier
J F
JF
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000097:blood / Q000175:diagnosis / Q000652:urine; D001798:Blood Proteins / Q000652:urine*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015550:Cell Degranulation / Q000502:physiology*; D002908:Chronic Disease; D047208:Eosinophil-Derived Neurotoxin; D004804:Eosinophils / Q000502:physiology*; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009498:Neurotoxins / Q000652:urine*; D011657:Pulmonary Eosinophilia / Q000097:blood / Q000175:diagnosis / Q000652:urine; D012008:Recurrence; D012260:Ribonucleases
D001798:Blood Proteins; D009498:Neurotoxins; D047208:Eosinophil-Derived Neurotoxin; D012260:Ribonucleases