Perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA), a serological marker of ANCA-associated vasculitis (AAV), may also predict the evolution of idiopathic pulmonary fibrosis (IPF) to microscopic polyangiitis (MPA), according to a study published in Diagnostics.

In this observational, retrospective, case-control study, the researchers compared 18 patients with IPF and p-ANCA positivity and 36 patients with seronegative IPF, matched for age and sex.

According to the results, the researchers observed a similar lung function decline in IPF patients with and without p-ANCA positivity. However, IPF patients positive for p-ANCA had better overall survival rates.

Half of the IPF patients positive for p-ANCA were classified as MPA due to renal involvement (55%) or skin signs (45%). Rheumatoid factor positivity at baseline was associated with the disease progression to MPA.

Read more about AAV comorbidities

“Patients with a usual interstitial pneumonia radiologic pattern on chest computed tomography and a p-ANCA positivity need close clinical and laboratory follow-ups aimed at early detection of signs of vasculitis,” Libra and colleagues emphasized.

“The inclusion of ANCA in the criteria for interstitial pneumonia with autoimmune features, together with the removal of the “morphological domain” (aimed to limit the inclusion of usual interstitial pneumonia patients), could improve the recognition of interstitial lung disease patients at risk of developing vasculitis. More studies are needed to demonstrate the efficacy of antifibrotic treatments in patients affected by this condition.”

MPA is a form of AAV with the highest prevalence of interstitial lung disease, often presented with a radiological pattern of usual interstitial pneumonia similar to IPF. Interstitial lung disease frequently precedes the clinical onset of vasculitis, hence establishing the correct diagnosis can be particularly challenging at disease onset.


Libra A, Muscato G, Ielo G, et al. Clinical and prognostic significance of p-ANCA positivity in idiopathic pulmonary fibrosis: a retrospective observational studyDiagnostics (Basel). Published online May 27, 2023. doi:10.3390/diagnostics13111882