Bronchoalveolar lavage fluid (BALF) in patients suffering from granulomatosis with polyangiitis (Wegener’s) (GPA) demonstrated an increased neutrophil cell count, elevated MPO, CXCL8/IL-8 and G-CSF concentrations and the presence of antineutrophil cytoplasmic antibodies, suggesting that the innate immune system, in particular PMNs, are crucial effector cells in this disease (42). This evidence concerns the gene CXCL8 and granulomatosis with polyangiitis.