A Comparison of the Clinical Features of ANCA-Positive and ANCA-Negative Idiopathic Pulmonary Fibrosis Patients

Abstract

Background: The existence of antineutrophil cytoplasmic antibody (ANCA)-positive pulmonary fibrosis (PF) has recently been recognized. Objectives: The aim of this study was to clarify whether there is any difference in the clinical features between ANCA-positive PF and ANCA-negative PF. Methods: A retrospective study was carried out on 53 patients with idiopathic PF whose myeloperoxidase (MPO)- and proteinase 3 (PR3)-ANCA levels were measured. After dividing the patients into ANCA-positive and ANCA-negative PF, we compared their symptoms, pulmonary function tests, chest CT findings, bronchoalveolar lavage findings, the effects of therapy and survival rates. Results: 17 of the 53 patients with idiopathic PF were MPO-ANCA-positive, 2 were PR3-ANCA-positive and 34 were negative for both ANCA types. Lactate dehydrogenase was lower in ANCA-positive PF than in ANCA-negative PF. However, there was no significant difference in the symptoms, lung function tests, CT findings and bronchoalveolar lavage findings. Corticosteroid therapy tended to be more effective in ANCA-positive PF, but the overall survival rate in ANCA-positive PF was not different from that in ANCA-negative PF. However, the low-titer (<50 EU) group showed better survival than the high-titer (≥50 EU) group in ANCA-positive PF. ANCA titers of the patients who developed microscopic polyangiitis were higher than of those who did not develop it in ANCA-positive PF. Conclusions: Our studies showed little difference in the clinical features between ANCA-positive and ANCA-negative PF. However, it may be important to measure ANCA when idiopathic PF is diagnosed, because a high titer of ANCA suggests a poor prognosis and the association with microscopic polyangiitis.

The oxidation induced by antimyeloperoxidase antibodies triggers fibrosis in microscopic polyangiitis

“…Pulmonary fibrosis is also a potentially severe manifestation of MPA, but mild pulmonary fibrosis is significantly associated with an increased rate of mortality [2][3][4]. Although pulmonary fibrosis in MPA might result from iterative episodes of alveolar haemorrhage, half of patients with pulmonary fibrosis have no history of haemoptysis and pulmonary fibrosis can be the initial manifestation of the disease, sometimes several years prior to the diagnosis of MPA [2,5].…”

“…In MPA, ANCAs exhibit mainly a perinuclear fluorescent pattern and are directed to myeloperoxidase (MPO). Although anti-MPO antibodies (Abs) are associated with pulmonary fibrosis [2,5], their role in this pathophysiological process has been poorly understood so far.…”

Idiopathic pulmonary fibrosis and p-ANCA positivity predating manifestations of systemic vasculitis

“…Here, we report two cases in which p-ANCA was negative at the time of diagnosis of pulmonary fibrosis and became positive during follow-up, predating the onset of fulminant vasculitis. There are no reported differences in the clinical or radio graphical characteristics of p-ANCA positive as compared to p-ANCA negative pulmonary fibrosis at the time of initial diagnosis [3]. However, in the presence of p-ANCA positivity, the clinical course of the disease may be affected, with increased morbidity and mortality observed [3,4].…”

A case of pulmonary fibrosis associated with rheumatoid arthritis, scleroderma sine scleroderma and ANCA associated vasculitis.

“…Patients with initial diagnosis of PF, occasionally acquire seropositivity for MPO-ANCA, which may develop to microscopic polyangitis (MPA) (Ando et al 2013). The prevalence of ANCA in patients with ILD in literature is suggested at 8-36% (Nozu et al 2009;Foulon et al 2008). Homma et al showed positive ANCA as an unfavorable prognostic factor in patients with pulmonary fibrosis (Homma et al 2004).…”

“…Homma et al showed positive ANCA as an unfavorable prognostic factor in patients with pulmonary fibrosis (Homma et al 2004). Nozu et al demonstrated that a high titer of ANCA is associated with a poor prognosis and higher risk for progression to MPA (Nozu et al 2009). In fact, in a study by Foulan et al, 41% of patients with PF and ANCA positivity developed MPA over time (Foulon et al 2008).…”