Despite variable effects of IL-9 in in vitro studies of allergic cellular processes [23-25], the treatment with a neutralizing anti-IL-9 antibody in vivo in our study did not protect airways from the abundant eosinophilia in BAL, arguing against anti-IL-9 having a potential as an anti-inflammatory treatment in established allergic disease. Here, IL9 is linked to Increased total eosinophil count.