Am. J. Respir. Crit. Care Med.,
Volume 164, Number 3, August 2001, 378-381
Validity and Safety of Sputum Induction by Inhaled
Uridine 5'-Triphosphate
JUN
TAMAOKI,
MITSUKO
KONDO,
HISATOSHI
KURODA,
KAZUTETSU
AOSHIBA,
KIYOSHI
TAKEYAMA,
JUNKO
NAKATA,
and
ATSUSHI
NAGAI
First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan
Inhalation of hypertonic saline during sputum induction causes
bronchoconstriction. We studied the validity and safety of sputum
induction by uridine 5'-triphosphate (UTP). Sputum was induced
by a 5-min inhalation of hypertonic saline (3%) on Day 1 and UTP
(5 mg/ml in 0.9% saline) on Days 8 and 15 in 16 healthy subjects
and 16 patients with mild-to-moderate asthma. Inhaled UTP produced twofold greater amounts of sputum than did hypertonic saline. There were significant differences in oxygen desaturation and bronchoconstriction during the procedure between the two
methods: the maximal fall in SaO2, the AUC of the SaO2-time response, and the fall in PEF were less in the subjects who received
UTP than in those who received hypertonic saline. Sputum total
cell and differential cell counts, with a high proportion of eosinophils in asthmatics, were similar between specimens obtained by
hypertonic saline and UTP. When we compared two consecutive
measurements on the UTP-induced sputum samples, the reproducibility calculated by the intraclass correlation coefficient was
high for the proportion of eosinophils, neutrophils, and macrophages. Therefore, inhalation of UTP aerosols may provide an effective, relatively noninvasive, valid, and reproducible method of
sputum induction for the assessment of airway inflammation in asthma.
Keywords: uridine triphosphate; induced sputum; airway inflammation; bronchoconstriction; asthma
