[Changes of exhaled nitric oxide and peripheral blood eosinophils in children with asthma].

OBJECTIVE

This study examined the levels of exhaled nitric oxide (eNO) and peripheral blood eosinophils (EOS) as well as the correlation between the two markers in children with bronchial asthma (AS),AS complicated by allergic rhinitis (AS/AR) and chronic cough variant asthma (CVA), in order to explore the value of eNOS detection in children with AS.

METHODS

The eNO level was measured using light-emitting electrochemical photometry in 12 children with AS, 29 children with AS/AR and 10 children with CVA. Peripheral blood EOS was counted by blood cell counter (Coulter JT). Forced expiratory volume in one second (FEV1) was assessed by lung function measurement. Thirty children without atopic disease and acute respiratory infection as well as without a family history of atopic diseasea served as the control group.

RESULTS

The levels of eNO and blood EOS in the AS, the AS/AR and the CVA groups were significantly higher than those in the control group (p<0.01). The AS/AR group showed increased levels of eNO (50.3 + or - 6.7 ppb) and EOS (5.9 + or -4.2 x 109 ) compared with the AS (30.5 + or - 8.8 ppb and 4.2 + or - 3.2 x 109 respectively) and the CVA groups (26.0 + or - 3.2 ppb and 3.7 + or - 6.9 x 109 respectively) (p<0.05). There were no significant differences in eNO and EOS levels between the AS and the CVA groups. The eNO level was positively correlated with the EOS level (r=0.51, p<0.05), but not with FEV1 (r=0.144, p>0.05) in the AS group.

CONCLUSIONS

NO is highly expressed in children with symptoms of atopy and can reflect the levels of eosinophilic airway inflammation in children with AS.