NEUTRAL ENDOPEPTIDASE (NEP)-3.4.24.11 IN SERUM AND BRONCHIAL HYPERREAGIBILITY

To study the correlation between the reagibility of the bronchial syst em and the concentration of neutral endopeptidase (NEP) in serum bronc hial challenges with acetylcholine (ACH) were performed in 60 patients with history of wheezing. Serum-NEP was measured using a newly establ ished ELISA. NEP was detected in the serum of 38 patients. A highly si gnificant correlation (p < 0,0006, r = 0,53, n = 38) between serum-NEP and FEV1 in the primary lung function was found. Dividing the patient s into a group with hyperreactive airways (n = 15) and a group without bronchial hyperreactivity (n = 23) - according to a positive ACH prov ocation - we found a significant correlation between FEV1 and serum NE P (p < 0,01. r = 0,52, n = 23) in the group without hyperreactivity (F EV1 decrease < 20% and R-aw increase < 100%), whereas this correlation surprisingly was nor seen in the group with bronchial hyperreactivity (FEV1 decrease > 20% and/or R-aw increase > 100%). A correlation betw een serum-NEP values and FEV1 decrease after ACH provocation was not f ound. In conclusion, the serum NEP levels do correlate with lung funct ion in patients with respect to FEV1. Bronchial hyperreactivity itself - according to the international definition - does not show this corr elation. These results could be interpreted that NEP probably plays a role in the regulation of the bronchomotor tone.