Pulmonary Involvement in Antineutrophil Cytoplasmic Antibodies-Associated Vasculitis

Pulmonary involvement at the time of diagnosis has been reported in patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). A UK study published in The Journal of Rheumatology evaluated patients with AAV, as defined by computed tomography (CT).

A total of 140 patients (75 women, 65 men; mean age at AAV diagnosis, 60.1 years) with thoracic CT performed on or after the onset of AAV were enrolled in the study. Of these patients, 79 had granulomatosis with polyangiitis (GPA) and 61 had microscopic polyangiitis (MPA). All patients were followed at a tertiary referral center vasculitis clinic. Radiologic patterns of pulmonary involvement, which were evaluated on the CT scans according to a predefined protocol, were compared with proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA specificity.

Overall, 77% of the patients had an abnormal thoracic CT scan. The most common abnormality observed among the participants was nodular disease (24%), in the majority of cases peribronchial nodules; this was followed by bronchiectasis (19%), pleural effusion (19%), pulmonary hemorrhage (14%), lymph node enlargement (14%), emphysema (13%), and cavitating lesions (11%).

Central airway disease and a nodular pattern of pulmonary involvement occurred significantly more often in PR3-ANCA–positive patients than in MPO-ANCA–positive patients (P <.05). Bronchiectasis and usual interstitial pneumonitis (UIP), on the other hand, were significantly more common among MPO-ANCA–positive patients (P <.05). Pleural effusion, lymph node enlargement, alveolar hemorrhage, and pulmonary venous congestion were also more prevalent in MPO-ANCA–positive patients.

The investigators concluded that pulmonary involvement is common among patients with AAV. In the present study, of 140 patients with AAV who underwent thoracic CT, pulmonary abnormalities were revealed in nearly 80%. Central airway disease was observed almost exclusively among patients with PR3-ANCA, whereas UIP was reported mainly in those with MPO-ANCA. These study findings appear to have important implications for the pathogenesis of AAV, as well as the investigation and management of patients with AAV.

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Reference

Mohammad AJ, Mortensen KH, Babar J, et al. Pulmonary involvement in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis: the influence of ANCA subtype [published online August 1, 2017]. J Rheumatol. doi:10.3899/jrheum.161224