Antineutrophil cytoplasmic antibody-associated interstitial lung disease: a review

Abstract

Over the past three decades, an increasing number of publications have reported the association between interstitial lung disease (ILD) and anti-neutrophil cytoplasmic antibody (ANCA) or ANCA-associated vasculitis (AAV). With this increased awareness, we have reviewed the literature to date and provide an update in this narrative review. The vast majority of cases of ILD have been shown to be in the setting of positive anti-myeloperoxidase antibody and can be present in up to 45% of patients of microscopic polyangiitis, though cases of ILD associated with proteinase 3 ANCA have rarely been reported. Pulmonary fibrosis and ANCA positivity can occur with or without systemic involvement. The pathogenetic mechanisms establishing the relationship between ANCA and the development of pulmonary fibrosis remain unclear. Histologic and radiographic features of ANCA-ILD most commonly reveal usual interstitial pneumonia or non-specific interstitial pneumonia patterns, though other atypical features such as bronchiolitis have been described. ILD in the setting of AAV has been associated with worse outcomes, and thus early identification and treatment in these patients is appropriate. We advocate that ANCA antibody testing be performed as a baseline evaluation in patients presenting with idiopathic interstitial pneumonia. Suggested treatment of ANCA-ILD includes immunosuppression and/or antifibrotic agents, though supporting data and clinical trials to substantiate use of these therapies are needed.

Anti-Inflammatory and/or Anti-Fibrotic Treatment of MPO-ANCA-Positive Interstitial Lung Disease: A Short Review

“…In previous reports, radiological analysis, especially by high-resolution computed tomography (HRCT), was used for the classification of patterns [27,28] in patients with MPO-ANCA-positive ILD. In patients with MPA, the most frequently occurring pattern was usual interstitial pneumonia (UIP) (50-78%), followed by nonspecific interstitial pneumonia (NSIP) (7-58%) and others (13-31%) [14,[29][30][31][32]. MPO-ANCA-positive ILD without systemic vasculitis (i.e., idiopathic ILD) also showed a similar tendency (UIP: 12.9-53.9%, non-UIP: 13.6-58.1%) [31,32].…”

“…We reported that an anterior upper lobe honeycomb-like lesion, which represents a concentration of cystic air spaces within the anterior aspect of the upper lobes (Figure 1B), might be found with higher frequency in MPO-ANCA-positive ILD and RA-ILD than in other etiologies associated with ILD [31,42]. Pathologically, MPO-ANCA-positive ILD even with a UIP pattern showed more prominent inflammatory cell infiltration and cellular bronchiolitis, unlike UIP/IPF (Figure 2A-E) [8,14,17,[33][34][35]. In other words, these pathological features correspond well to the presence of a radiological feature such as increased attenuation around areas of honeycombing and traction bronchiectasis [30,31,34].…”

“…In addition, patients with pulmonary fibrosis and ANCA positivity but without other manifestations of systemic vasculitis have also been reported, which was sometimes diagnosed as "pulmonary-limited type of ANCA-associated vasculitis" [8,12]. Furthermore, ANCA-positive conversion has been described in patients with an initial diagnosis of idiopathic ILD, with manifestations of systemic vasculitis occurring in some patients [13,14]. However, it is unclear whether ILD observed in the presence of only MPO-ANCA differs from idiopathic ILD and ILD with overt MPA [14].…”

“…Furthermore, ANCA-positive conversion has been described in patients with an initial diagnosis of idiopathic ILD, with manifestations of systemic vasculitis occurring in some patients [13,14]. However, it is unclear whether ILD observed in the presence of only MPO-ANCA differs from idiopathic ILD and ILD with overt MPA [14]. Needless to say, this problematic matter has influenced the treatment strategy of MPO-ANCA-positive ILD patients without systemic vasculitis as a form of idiopathic ILD.…”

KL-6 in ANCA-Associated Vasculitis Patients with and without ILD: A Machine Learning Approach

“…Patients with MPA, especially those who are ANCA-MPO-positive, may have interstitial lung disease (ILD) [ 4 , 5 ], which is associated with high morbidity and mortality as it is often underdiagnosed and responds poorly to conventional treatments [ 6 ]. Interstitial lung disease associated with AAV does not have specific imaging or bronchoalveolar lavage (BAL) findings.…”