Asthma and chronic bronchitis are diseases:that may present similar symptom
s. Because eosinophil granulocytes play an,important role in the pathogenes
is of asthma, the assessment of eosinophilic inflammation may be useful in
making a differential diagnosis of these two diseases. This study investiga
ted the serum and sputum eosinophil cationic protein (ECP) levels in childr
en with asthma and chronic bronchitis and compared them with controls. Fift
y asthmatic patients being treated for mild or moderately severe asthma at
a university hospital were enrolled in the study. Fifteen children with sym
ptoms of cough and sputum production lasting more than 3 months were studie
d in the chronic bronchitis group and 25 healthy children were included in
the control group. Asthmatic patients were divided into subgroups:according
to the presence or absence of asthmatic exacerbations. Clinical evaluation
and determination of ECP concentrations in serum and sputum were performed
for each group. In-creased activity of eosinophils was found in patients w
ith asthma as assessed by high serum ECP (mean 21.44 +/- 20.33 mu g/L) and
sputum ECP (mean 129.65 +/- 125.01 mu g/L) levels. In patients diagnosed wi
th chronic bronchitis, serum ECP levels were similar to those of the contro
l group (mean serum ECP 11.04 +/- 10.23 mu g/L and 12.07 +/- 6.12 mu g/L, r
espectively). More importantly, sputum ECP levels of the chronic bronchitis
group were much lower (mean 53.36 +/- 55.43 mu g/L) than those in patients
with asthma (mean 129.65 +/- 125.01 mu g/L). The serum and sputum ECP leve
ls of the asthmatic patients who were evaluated during an acute exacerbatio
n were also higher than those in the chronic bronchitis group. Sputum ECP l
evels may be helpful in the differential diagnosis of asthma and chronic br
onchitis in children.