Thulborn, Catherine Borg,
Clare Connolly and Ian Pavord Nuffield Department of Medicine,
University of Oxford, Oxford, United
Leukotriene-E4 (LTE4) and prostaglandin-D2 (PDG2) are lipid mediators
associated with Type-2 inflammation in asthma. Both are increased in
the urine of patients with asthma. We have assessed concentrations in
induced sputum in patients with asthma and tested the hypothesis that
concentrations vary according to the pattern of inflammation.
Induced sputum was obtained from 7 healthy volunteers and 44 patients
with asthma (GINA steps 2-5), and processed according to our usual
procedures. LTE4 and PGD2 were measured using commercially available
ELISA kits. Patients with asthma were stratified by induced sputum
eosinophil count, with counts > 3% classified as eosinophilic.
Geometric mean (log SD) LTE4 concentration was 218 (0.47), 1237 (0.44)
and 5541 (0.94) pg/ml and PGD2 concentration 2289 (0.2), 3366 (0.33)
and 4575 (0.3) pg/ml in controls, patients with non-eosinophilic and
patients with eosinophilic asthma respectively (figure). LTE4 was
significantly different across groups by one-way ANOVA (p=0.0005). No
difference was seen between mild-moderate (GINA 2-3) and severe asthma
(GINA 4-5) groups or in patients with a self-reported aspirin
sensitivity (shown as open data points).
LTE4 is increased in the sputum of patients with asthma compared to
healthy controls, and in eosinophilic compared to non-eosinophilic
asthma. Our data does not support a specific role in patients with
severe asthma or in patients with aspirin sensitivity.