Background/Purpose:

Interstitial lung disease (ILD) may occur in the presence of autoimmune elements without meeting criteria for a distinctive Connective Tissue Disease.

The European Respiratory Society/ American Thoracic Society proposed a term ‘interstitial pneumonia with autoimmune features’ (IPAF) to further classify these individuals based on a combination of features from three domains: clinical, serologic and pulmonary morphologic.

We sought to assess the incidence of IPAF previously classified as idiopathic interstitial pneumonia or ILD associated with undifferentiated connective tissue disease (UCTD). Hurdles in the reclassification process were also highlighted.

Methods:

Our institution’s pathology database was scanned for 10 years of surgical lung biopsy data. Patients with biopsy proven nonspecific interstitial pneumonia (NSIP) were studied. Their clinical and serologic data was collated. Cases with a prior diagnosis of idiopathic NSIP or ILD associated with UCTD were screened by the ERS/ATS criteria for IPAF and reclassified.

Results:

17 of 278 surgical lung biopsies performed from 2006 to 2016 for ILD were reported as NSIP. 41% of these NSIP cases were previously classified as idiopathic, 17.7 % as associated with UCTD and the remaining had established autoimmune etiologies for an ILD.

57% of the prior idiopathic cases were reclassified as IPAF and 100% of the prior UCTD were reclassified as IPAF. All cases met morphologic criteria (NSIP on lung biopsy), 57% had serologic criteria and 71% met clinical criteria. The serologic workup was incomplete in a few patients.

Conclusion:

Previous diagnoses of UCTD-ILD and Idiopathic NSIP may be reclassified as IPAF. This will help promote future research to guide management of this unique population. It is important to stress the need for serologic work up of ILD patients, to enable complete assessment and appropriate classification of patients.

« Back to 2018 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/interstitial-pneumonia-with-autoimmune-features-ipaf-nsip-hurdles-to-reclassification-of-overlapping-ilds/