Effect of anti-IgE in occupational asthma caused by exposure to low molecular weight agents

Background The role of immunoglobulin (Ig)-E in occupational asthma (OA) due to low molecular weight (LMW) agents is not well established compared to classical atopic asthma. In the present study we evaluate whether anti-IgE monoclonal antibody (mAb) has an effect in a mouse model of OA, using persulfate salts. Methods On days 1 and 8, BALB/C mice were dermally sensitized with 5% ammonium persulfate (AP) or dimethyl sulfoxide (DMSO). On days 15, 18 and 21 animals were injected intraperitoneally with anti-IgE mAb or PBS 6 hours before challenge with AP or saline. Airway hyperresponsiveness (AHR) using a methacholine test, airway inflammation in bronchoalveolar lavage (BAL) and lung tissue and total free IgE in serum samples were analyzed 24, 48 and 96 hours after the last challenge. Results Anti-IgE mAb treatment almost completely neutralized free serum IgE. In AP sensitized and challenged mice, anti-IgE mAb treatment abolished AHR 24h and 48h after the last challenge and significantly reduced the total number of eosinophils and neutrophils 48h and 96h after the last AP challenge compared with non-treated mice. Levels of interleukin (IL)-13 in BAL were also significantly decreased after anti-IgE administration 24h and 48h after the last AP challenge. Histological analysis of the lung sections from anti-IgE-treated mice revealed normal inflammatory patterns similar to control groups 48h after the last challenge. Conclusions Anti-IgE-treated mice showed a significant improvement in asthma features related to the AHR and airway inflammation. Anti-IgE mAb has positive effects in OA induced by persulfate salts. This article is protected by copyright. All rights reserved.