Indeed, previous research showed that the infection of human bronchial epithelial cells, human tracheobronchial epithelial cells, and human alveolar A549 cells with seasonal influenza A(H3N2) virus, promotes robust upregulation of CXCL17. However, the infection with more virulent A(H5N1) and A(H7N9) influenza virus subtypes induces minor changes in the expression of CXCL17 (18). Here, CXCL17 is linked to infection.