CXCL13 and pulmonary fibrosis: Moreover, high levels of CXCL13 expression have been proved to be associated with pulmonary fibrosis that is the prominent feature of infection with 2009 pandemic influenza A (H1N1) virus [59, 60], suggesting that CXCL13 may play an important role in pulmonary diseases caused by influenza virus infection and still need to be further investigated.