Novel advances in the diagnosis of ILDs: 2nd edition of ERS-ALAT Webinars in Respiratory Medicine

In a recent personal view published in 2023 Selman Moises, Pardo Annie and Wells Athol, well-known experts in the interstitial lung diseases field; advocate the designation of a UIP pattern as a single, discrete diagnostic entity, amalgamating its primary form and secondary processes in other fibrotic ILD such as hypersensitivity pneumonitis (HP) and rheumatoid arthritis (RA) with UIP(1). In many series, exploring outcomes in patients with IPF, fHP with UIP (fHP-UIP), rheumatoid arthritis with UIP (RA-UIP), and other forms of UIP, mortality has, on average, been similar to IPF whether UIP was identified histologically or judged to be a definite feature based on the CT pattern (1) Although these diseases have different initiating pathogenic mechanisms, in some part of disease evolution, they display converging pathways with IPF. This concept strengthens the perception that during ILD progression, common pathways might take place, provoking similar lung remodeling and fibrosis despite differences in underlying causes (1). Being able to identify the presence of UIP in non IPF fibrotic interstitial diseases could have therapeutic implications regarding the use of immunosuppressive and antifibrotic treatment.

In this sense, in recent years, new tools have emerged for the diagnosis of interstitial diseases and the identification of the UIP pattern: lung cryobiopsy and genomic classifier. Transbronchial lung cryobiopsy (TBLC) has been emerged as a less invasive alternative to surgical lung biopsy and it’s suggested as a replacement test as a first step in patients considered eligible to undergo SLB (2). In the COLDICE study, a high agreement between TBLC and SLB was found for interstitial lung disease diagnosis: Histopathological agreement between TBLC and SLB was 70.8% (weighted κ 0.70, 95% CI 0.55–0.86) and diagnostic agreement at MDD was 76.9% (κ 0.62, 0Ø47–0.78)(3). Also in this study, UIP features of patchy fibrosis, fibroblast foci, and the absence of alternative diagnostic features at transbronchial lung cryobiopsy had an odds ratio of 23·4 for the presence of UIP in paired surgical lung biopsies (4). On the other hand, the CAN – ICE study demonstrated moderate TBCB–MDD and SLB–MDD diagnostic agreement for ILD (5). Finally, in the update of the Clinical Practice Guideline about Idiopathic Pulmonary Fibrosis a conditional recommendation was made to regard transbronchial lung cryobiopsy as an acceptable alternative to surgical lung biopsy in centers with appropriate expertise for patients with ILD of undetermined type (6).

A genomic classifier was developed with machine learning and whole transcriptome RNA sequencing using lung tissue obtained by SLB. More recently, it was introduced and validated for lung tissue obtained by transbronchial forceps biopsy which can detect, a gene expression signature concordant with the UIP pathology pattern (7). Genomic classifier testing predicts histopathologic UIP in patients with ILD with a specificity of 92% and improves diagnostic confidence; however, sensitivity is only 68%, and testing is not widely available (8). No recommendation for or against the addition of genomic classifier testing for the purpose of diagnosing UIP in patients with ILD of undetermined type was made in the update of the Clinical Practice Guideline about Idiopathic Pulmonary Fibrosis (6).

Both tests have the important limitation of not discriminating definitively between IPF and other forms of UIP. This distinction is not made by the genomic classifier, and in the case of transbronchial lung cryobiopsy, ancillary features suggestive of secondary UIP may not be captured by the relatively small size of samples, compared with tissue obtained at surgical biopsy.(1)

Educational aims

• Emphasize the importance of the UIP pattern in both IPF and other fibrotic interstitial diseases, recognizing commonalities from a pathophysiological perspective. Being able to identify prognostic implications and treatment.
• Highlight the role of cryobiopsy in clinical practice to identify the UIP pattern through a clinical case.
• Recognize the potential application in daily practice of the genomic classifier to identify UIP pattern in patients with ILD under study.

Topics

• The importance of UIP pattern.
• Role of cryobiopsy in the diagnosis of fibrotic ILD
• Genomic classifier as diagnostic tool to identify UIP pattern in clinical practice.

Target audiences

• Clinicians
• Pulmonologists
• ILD specialists
• Bronchoscopists

Format

This webinar will include three lectures, followed by a final round table discussion.

CME credit

An application for accreditation of this webinar has been made to the European Board for Accreditation in Pneumology (EBAP) for 1 CME credit per 1-hour attendance. If accredited, the CME credit will be granted upon attendance of at least 60 minutes during the live webinar only.

What is a webinar?

A webinar closely simulates a lecture-based teaching experience. The speaker can interact with the audience, just as in a classroom setting. During the webinar, you will be asked to share your opinion on issues related to the topic using interactive polls.

All participants will be able to hear the lecturer and see the slides throughout the presentation. As a participant you will be able to pose questions or discuss ideas with the other participants via the text chat facility and the speaker will respond to the questions via the microphone.

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Bibliography:

1. Selman M, Pardo A, Wells AU. Usual interstitial pneumonia as a stand-alone diagnostic entity: the case for a paradigm shift? Lancet Respir Med. 2023;11(2):188–96.
2. Korevaar DA, Colella S, Fally M, Camuset J, Colby T V., Hagmeyer L, et al. European Respiratory Society guidelines on transbronchial lung cryobiopsy in the diagnosis of interstitial lung diseases. Eur Respir J. 2022;60(5).
3. Troy LK, Grainge C, Corte TJ, Williamson JP, Vallely MP, Cooper WA, et al. Diagnostic accuracy of transbronchial lung cryobiopsy for interstitial lung disease diagnosis (COLDICE): a prospective, comparative study. Lancet Respir Med. 2020;8(2):171–81.
4. Cooper WA, Mahar A, Myers JL, Grainge C, Corte TJ, Williamson JP, et al. Cryobiopsy for identification of usual interstitial pneumonia and other interstitial lung disease features further lessons from COLDICE, a Prospective Multicenter Clinical Trial. Am J Respir Crit Care Med. 2021;203(10):1306–13.
5. Fortin M, Liberman M, Delage A, Dion G, Martel S, Rolland F, et al. Transbronchial Lung Cryobiopsy and Surgical Lung Biopsy: A Prospective Multi-Centre Agreement Clinical Trial (CAN-ICE). Am J Respir Crit Care Med. 2023;207(12):1612–9.
6. Raghu G, Remy-Jardin M, Richeldi L, Thomson CC, Antoniou KM, Bissell BD, et al. Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline. Am J Respir Crit Care Med. 2022;205(9):E18–47.
7. Raghu G, Flaherty KR, Lederer DJ, Lynch DA, Colby T V., Myers JL, et al. Use of a molecular classifier to identify usual interstitial pneumonia in conventional transbronchial lung biopsy samples: a prospective validation study. Lancet Respir Med. 2019;7(6):487–96.
8. Kheir F, Uribe Becerra JP, Bissell B, Ghazipura M, Herman D, Hon SM, Hossain T, Khor YH, Knight SL, Kreuter M, Macrea M, Mammen MJ, Martinez FJ, Poletti V, Troy L, Raghu G WK. Use of a Genomic Classifier in Patients with Interstitial Lung Disease: A Systematic Review and Meta-Analysis. Ann Am Thorac Soc. 2022;19(5):827–32.