Measurement of house dustmite-specific IgA antibody in sputum from asthmatics

Abstract

To evaulate the possible pathogenetic significance of allergen-specific IgA antibody in respiratory secretion from asthmatics, we measured house dust mite(HDM)-specific IgA antibody in 3% saline-induced sputum from 23 HDM-sensitive asthmatics, 4atopic asthmatics without mite-sensitivity, 6 non-atopic asthmatics, and 13 nonatoplc, non-asthmatic controls (including 6 non-atopic healthy controls, 4 patients with chronic bronchitis, and 3 patients with rheumatoid arthritis) by ELISA. We also measured HDM-specific IgA antibody in serum and numbers of eosinophils in sputum.

1) Levels of HDM-specific IgA antibody In sputum from mite-sensitive asthmatics

were significantly higher than those from non-atopic, non-asthmatic controls and

non-atopic asthmatics(p<0.05). Levels of HDM-specific IgA antibody in sputum from

atopic asthmatics without mitesensitivity were significantly higher than those from

non-atopic, non-asthmatic controls (p<0.05), however HDM-specific IgA/albumin raito

was not significantly different between two groups (p>0.05).

2) The ratio of HDM-specific IgA antibody to albumin in sputum was not significantly different in mite-sensitive asthmatics with sputum eosulophila (≥5% of 200 counted leukocytes) and those without sputum eosinophilia(p>0.05).

3) The ratio of HDM-specific IgA to albumin in sputum from asthmatics was higher

than that of serum.

4) There was no significant correlation of HDM- specific IgA/albumin ratios between

serum and sputum (p>0.05).

5) When comparing sputum and saliva samples from 7 mite-sensitive asthmatics,

levels of HDM-specific IgA antibody in sputum were significantly higher than those in saliva (p<0.05).

In conclusion, HDM-specific IgA anti-body was increased in sputum from HDM-sensitive asthmatics, and it might be locally produced from bronchial mucosa. To evaluate the pathogenetic significance of allergen-specific IgA antibody in respiratory

secretion from asthmatics, further studies might be needed.