In a case series study of 9 patients with MPO-ANCA idiopathic interstitial pneumonia (IIP), small airway disease was found in all the patients, lymphoid follicles in seven patients, UIP with areas of NSIP in eight patients, UIP and diffuse alveolar damage (DAD in two patients and no vasculitis in any patients (155). Here, MPO is linked to idiopathic interstitial pneumonia.