Prevalence and outcome of pulmonary fibrosis in microscopic polyangiitis

Abstract

We sought to determine the type of pulmonary involvement in microscopic polyangiitis (MPA), primarily focusing on pulmonary fibrosis (PF), its prevalence, temporal relationship with other disease manifestations and outcome.33 patients (16 males) with biopsy proven perinuclear anti-neutrophilic cytoplasmic antibodypositive MPA (age 63.5 yrs) participated in the study. Pulmonary involvement was assessed using standard methods, including radiographic imaging (chest radiographs and high-resolution computed tomography), pulmonary function testing, bronchoscopy and bronchoalveolar lavage, and, if indicated, lung biopsy. All-cause mortality was analysed by the Kaplan-Meier method and was compared between MPA patients with and without PF.At the time of diagnosis, renal involvement was detected in all patients, with renal biopsies being consistent with segmental necrotising glomerulonephritis in all patients. The most common respiratory symptom was haemoptysis, which was found in nine (27%) patients. PF was present in 12 (36%) patients at the time of diagnosis, whereas one patient developed PF while on therapy ,10 yrs after disease diagnosis. In seven patients with PF, respiratory symptoms related to fibrosis preceded other disease manifestations by a median (range) period of 13 (5-120) months. Patients were followed up for a period of 38¡30 months. Presence of PF was associated with increased mortality (p50.02), with six deaths occurring in the fibrotic group and one in the nonfibrotic group. In the fibrotic group most deaths were related to PF.PF occurs frequently in MPA, may precede other disease manifestations by a variable length of time and has a poor prognosis.

Prevalence and Responsiveness to Treatment of Lung Abnormalities on Chest Computed Tomography in Patients With Microscopic Polyangiitis: A Multicenter, Longitudinal, Retrospective Study of One Hundred Fifty Consecutive Hospital‐Based Japanese Patients

“…Although this has been previously reported in the literature (4,5,7,8,(27)(28)(29)(30)(31), we analyzed CT images in sequential hospital-based patients before they received treatment and determined the prevalence of each imaging component of ILD (Table 2). Ground-glass opacity was the most prevalent component, which indicates that a large proportion of MPA patients have an active inflammatory process in the lungs before they receive treatment.…”

“…Diffuse alveolar hemorrhage (DAH) is a well-described pulmonary manifestation of small vessel vasculitis (3,6). However, interstitial lung disease (ILD) was recently recognized as a major pulmonary manifestation in patients with MPA (7,8), although its pathogenesis remains largely unknown. Even more intriguingly, a previous histopathologic analysis showed that a wide variety of extravascular pulmonary injuries, including airway lesions, can be observed in patients with AAVs (9).…”

An official European Respiratory Society/American Thoracic Society research statement: interstitial pneumonia with autoimmune features

“…Although ANCA panel positivity has been reported with interstitial pneumonia (and usual interstitial pneumonia (UIP) pattern disease in particular) and may reflect microscopic polyangiitis or another vasculitic disease [43,44], these autoantibodies are not included in the serologic domain because they are associated with the vasculitides, rather than the CTD-ILD spectra of disorders.…”

Monitoring with serum SP-A, SP-D, and KL-6 in a patient with interstitial pneumonia complicated with ANCA-associated glomerulonephritis

“…It is known that diffuse alveolar hemorrhage is mainly due to alveolar capillaritis; however, the pathogenesis of IP remains unclear [1]. Recurrent occult alveolar hemorrhage has been suggested as a putative mechanism leading to pulmonary fibrosis in patients with ANCA-associated vasculitis [9]. Alternatively, the authors of several studies have suggested that MPO antibodies may cause pulmonary tissue injury through the release of products of activated neutrophils [10].…”

“…These data suggest that the SP-D level may have been a sensitive marker of IP disease activity in our patient. Takahashi et al [9] demonstrated that SP-D is more useful than SP-A in detecting interstitial lung disease in patients with progressive systemic sclerosis. Since the serum MPO-ANCA remained negative in our patient when her IP deteriorated, the serum MPO-ANCA level may not be a reliable marker for monitoring disease activity in the lungs.…”