Segmental Allergen Challenge Regulates Gene Expression In Bronchoalveolar Lavage (BAL) Cells From Atopic and Mild Asthmatic Subjects

Segmental allergen challenge increases the percentage of eosinophils in bronchoalveolar lavage (BAL) cells. Mepolizumab, an anti-IL-5 therapeutic antibody, decreases the number of eosinophils in bronchoalveolar lavages (BAL). The use of both procedures allows to define genes that are either expressed by eosinophils or dependent on eosinophil presence in the airways. Cells from Bronchoalveolar lavages (BAL) are obtained by bronchoscopy before (V5) and 48 h after a segmental allergen challenge (V6) in atopic and mild astmatics. This procedure was repeated in the same two subjects 2 months later and 1 month after an injection of mepolizumab (V22 is before challenge and V23 after challenge). Cells were immediately lysed and isolated total RNAs were analyzed using the Human Genome 1.0 ST GeneChip arrays (Affymetrix, Santa Clara, CA).