Allergen inhalation challenge induces decrease of serum neutral endopeptidase (NEP) in asthmatics

There is accumulating evidence that tachykinins are implicated in inflammat ion, including asthma. Therefore, we hypothesized that the neutral endopept idase (NEP), under challenge conditions, could be affected. Serum from 21 a sthmatics and six healthy volunteers was sampled before, 30. and 120 min af ter allergen challenge. NEP-IR was determined using an ELISA and was found in all subjects. Compared to prechallenge, no difference was seen between a sthmatics and controls; however, under challenge conditions, NEP-IR in asth matics was significantly lower (30 min, P = 0.058; 120 min, P = 0.0017, res pectively). This finding supports indirectly the hypothesis that tachykinin s are released during allergen exposure, and suggests a regulatory role of NEP. (C) 2000 Elsevier Science Inc. All rights reserved.