Prevalence and Clinical Significance of Antineutrophil Cytoplasmic Antibodies in North American Patients with Idiopathic Pulmonary Fibrosis.
Chest. 2019 Jun 07;:
Authors: Liu GY, Ventura IB, Achtar-Zadeh N, Elicker BM, Jones KD, Wolters PJ, Collard HR, Adegunsoye A, Strek ME, Ley B
BACKGROUND: Antineutrophil cytoplasmic antibodies (ANCA) have been reported to occur in 7-10% of patients with idiopathic pulmonary fibrosis (IPF), but their clinical relevance remains unclear. The aim of this study was to estimate the prevalence of ANCA antibodies in a North American population with IPF and evaluate their clinical significance.
METHODS: This was a retrospective study of two independent cohorts of patients diagnosed with idiopathic pulmonary fibrosis (IPF) at the University of California San Francisco (discovery cohort) and the University of Chicago (replication cohort). Myeloperoxidase (MPO) and proteinase 3 (PR3)-ANCA antibodies were measured in all patients. Prevalence and associations of ANCA antibodies with clinical characteristics and transplant-free survival were evaluated.
RESULTS: A total of 14/353 (4.0%, 95% CI 2.2-6.5) and 20/392 (5.1%, 95% CI 3.1-7.8) of patients with IPF were positive for ANCA-antibodies at the time of diagnosis in the discovery and replication cohorts, respectively. Among those positive for MPO-antibodies, 2/6 (33%) in the discovery cohort and 3/12 (25%) in the replication cohort developed vasculitis. None of the PR3-positive patients developed vasculitis. ANCA-positive patients were more likely to be female compared to ANCA-negative patients, and were more likely to have some ground glass opacities on CT. In the combined cohort of 745 patients, median transplant-free survival was not significantly different in ANCA-positive versus ANCA-negative patients (p = 0.57).
CONCLUSIONS: ANCA-antibody positivity is uncommon in North American patients with IPF and not associated with baseline disease severity or transplant-free survival; however, a significant proportion of MPO-positive IPF patients develop clinical vasculitis.; Abbreviation List: ANCA: Antineutrophil cytoplasmic antibodies; CLIA: Clinical Laboratory Improvement Amendments; CT: Computed tomography; CTD: Connective tissue disease; DLCO: Diffusing capacity of the lung for carbon monoxide; FEV1: Forced expiratory volume in one second; FVC: Forced vital capacity; HR: Hazard ratio; ILD: Interstitial lung disease; IPF: Idiopathic pulmonary fibrosis; IPAF: Interstitial pneumonia with autoimmune features; MPA: microscopic polyangiitis; MPO: Myeloperoxidase; PR3: Proteinase 3; TLC: Total lung capacity; UC: University of Chicago; UCSF: University of California San Francisco; UIP: Usual interstitial pneumonia.
PMID: 31181198 [PubMed - as supplied by publisher]