Poletti, Venerino

Abstract Accumulating evidence suggests dysregulated immune checkpoint (IC) signaling can exacerbate COVID-19 severity, but the role of these molecules in the pathogenesis of fatal COVID-19-related diffuse alveolar damage (DAD) remains elusive. Understanding how IC proteins influence acute lung injury due to COVID-19 can provide insights into potential therapeutic strategies to modulate immune responses and improve patient outcomes. Here, in a single-center autopsy cohort, we determined the cellular localization of ICs in lung tissue from cases of fatal COVID-19, DAD-comparators, and non-fibrotic controls by using immunohistochemistry, and investigated their association with clinical outcomes. We expanded our findings by performing analyses of publicly available single-cell RNA sequencing datasets from patients with fatal COVID-19 and non-fibrotic controls. We demonstrated the presence of protein-protein interaction networks of ICs in the lung cellular niche by performing transcriptomic profiling of lung tissue-derived RNA counts from patients with fatal COVID-19. Further, we leveraged data from the largest international, multi-center COVID-19 autopsy cohort and validated that, among patients with fatal COVID-19, those with higher PD-L1/CD274 expression in lung endothelial cells had more rapid clinical deterioration. Lastly, in a cohort of individuals with early COVID-19, IC plasma protein levels were elevated in those with persistent SARS-CoV-2 RNAemia and adverse clinical outcomes. Collectively, our data provide unique pathological insights into the role of IC dysregulation and differential disease severity in COVID-19.

AimTransbronchial cryobiopsies are increasingly used for the diagnosis of interstitial lung disease (ILD), but there is a lack of published information on the features of specific ILD in cryobiopsies. Here we attempt to provide pathological guidelines for separating usual interstitial pneumonia (UIP) of idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis (FHP) and connective tissue disease‐associated ILD (CTD–ILD) in cryobiopsies.MethodsWe examined 120 cryobiopsies from patients with multidisciplinary discussion (MDD)‐established CTD–ILD and compared them to a prior series of 121 biopsies from patients with MDD‐established IPF or FHP.ResultsA non‐specific interstitial pneumonia (NSIP) pattern alone was seen in 36 of 120 (30%) CTD–ILD, three of 83 (3.6%) FHP and two of 38 (5.2%) IPF cases, statistically favouring a diagnosis of CTD–ILD. The combination of NSIP + OP was present in 29 of 120 (24%) CTD–ILD, two of 83 (2.4%) FHP and none of 38 (0%) IPF cases, favouring a diagnosis of CTD–ILD. A UIP pattern, defined as fibroblast foci plus any of patchy old fibrosis/fibrosis with architectural distortion/honeycombing, was identified in 28 of 120 (23%) CTD–ILD, 45 of 83 (54%) FHP and 27 of 38 (71%) IPF cases and supported a diagnosis of FHP or IPF. The number of lymphoid aggregates/mm2 and fibroblast foci/mm2 was not different in IPF, CTD–ILD or FHP cases with a UIP pattern. Interstitial giant cells supported a diagnosis of FHP or CTD–ILD over IPF, but were infrequent.ConclusionsIn the correct clinical/radiological context the pathological findings of NSIP, and particularly NSIP plus OP, favour a diagnosis of CTD–ILD in a cryobiopsy, but CTD–ILD with a UIP pattern, FHP with a UIP pattern and IPF generally cannot be distinguished.

Bronchoalveolar lavage and lung biopsy (LBx) are helpful in patients with connective tissue diseases (CTD) and interstitial lung diseases (ILD) regardless of cause, including infectious, noninfectious, immunologic, or malignant. The decision whether to perform only bronchoalveolar lavage (BAL), and eventually a subsequent LBx in case of a nondiagnostic lavage, or one single bronchoscopy combining both sampling methods depends on the clinical suspicion, on patient’s characteristics (e.g. increased biopsy risk) and preferences, and on the resources and biopsy techniques available locally (e.g. regular forceps versus cryobiopsy). In CTD-ILD, BAL has major clinical utility in excluding infections and in the diagnosis of specific patterns of acute lung damage (e.g. alveolar hemorrhage, diffuse alveolar damage, and organizing pneumonia). LBx is indicated to exclude neoplasm or diagnose lymphoproliferative lung disorders that in CTD patients are more common than in the general population. Defining BAL cellularity and characterizing the CTD-ILD histopathologic pattern by LBx can be helpful in the differential diagnosis of cases without established CTD [e.g. ILD preceding full-blown CTD, interstitial pneumonia with autoimmune features (IPAF)], but the prognostic and theragnostic role of those findings remains unclear. Few studies in the pretranscriptomics era have investigated the diagnostic and prognostic role of BAL and LBx in CTD-ILD, and it is reasonable to hypothesize that future studies conducted applying innovative techniques on BAL and LBx might open new and unexpected avenues in pathogenesis, diagnosis, and treatment approach to CTD-ILD. This is particularly desirable now that a new drug treatment era is emerging, in which we have more than one therapeutic choice (immunosuppressive agents, antifibrotic drugs, and biological agents). We hope that future research will pave the path toward precision medicine providing data for a more accurate ILD-CTD endotyping that will guide the physicians through targeted therapeutic choices, rather than to the approximative approach ‘one drug fits them all’.

Abstract Rationale Lung biopsy (LBx) has a relevant role in the prediction of prognosis of interstitial lung diseases (ILDs), but its impact on the clinical management of patients remains unexplored. Objectives This study evaluates whether LBx may change the therapeutic strategy and assesses the effect of diagnostic reclassification after LBx on long-term prognosis. Methods We evaluated the LBx of 426 consecutive patients with ILDs, without a definite usual interstitial pneumonia pattern on high-resolution computed tomographic imaging. A total of 266 patients underwent transbronchial lung cryobiopsy (TBLC), and 160 patients underwent surgical lung biopsy (SLB). The multidisciplinary team (MDT) determined a diagnosis with high or low confidence, and a management strategy, both before and after the LBx data. Results Final MDT diagnoses were 189 idiopathic pulmonary fibrosis (IPF), 143 non-IPF fibrotic ILDs, and 94 nonfibrotic ILDs. LBx data changed the management strategy in 145 cases (34%), with similar results for TBLC and SLB (the treatment strategy changed in 31.5% of TBLC cases, 84/266, P < 0.001, and in 38% of SLB, 61/160, P < 0.001). After LBx, the MDT was less inclined to “wait and see” (from 15% to 4% of cases, P < 0.001) or to prescribe steroids only (from 54% to 37%, P < 0.001) and was more confident to treat with antifibrotics (from 23% to 44%, P < 0.001) or immunosuppressive drugs (from 7% to 14%, P < 0.001). The therapeutic strategy changed in 70% of reclassified cases (60/85) and in 59% of cases in which LBx increased the MDT confidence (84/142). Reclassification significantly impacted the outcome. The cases classified as non-IPF by clinician and radiologist and then reclassified to be IPF after LBx showed a significantly worse survival compared with non-IPF confirmed cases (adjusted hazard ratio [HR], 3.8; 95% confidence interval [CI], 1.75–8.3); P = 0.001. Cases initially classified as IPF and then reclassified as non-IPF after LBx showed a better prognosis compared with IPF confirmed cases (HR, 0.41; 95% CI, 0.18–0.94; P = 0.03). Conclusions Reclassification of cases with LBx data increased diagnostic confidence and changed the therapeutic strategy in one-third of cases. Pathologic reclassification of cases refined prognosis prediction. Patients classified as non-IPF by clinician and radiologist and then reclassified IPF after LBx had worse prognosis compared with the non-IPF confirmed cases.

Context.— Transbronchial cryobiopsy has recently been proposed as an alternative to surgical biopsy in the diagnosis of diffuse lung disease. Objective.— To familiarize pathologists with transbronchial cryobiopsy, including what it is, how it is performed, how it compares to other techniques of lung biopsy in diffuse lung disease, what are the technical issues relating to it, what the complications are, how cryobiopsies should be interpreted, and the clinical usefulness of cryobiopsy. Data Sources.— All the available literature on cryobiopsy in diffuse lung disease through May 2016, primarily in the last 5 years, was reviewed, and some unpublished data known to the authors were included. Conclusions.— Cryobiopsies are considerably larger than forceps biopsies and allow pattern recognition approaching that of a surgical lung biopsy in many cases. Artifacts associated with cryobiopsy are minimal. In comparison with surgical lung biopsies, the diagnosis rate with cryobiopsies is lower, in the neighborhood of 80%, versus higher than 90% for surgical lung biopsies. Cryobiopsy is proposed as an alternative to surgical lung biopsy and a technique that may appreciably decrease the number of patients who require surgical lung biopsy for diagnosis. This is important because the mortality from cryobiopsy is very small (0.1% to date) compared with surgical lung biopsy (1.7% for elective procedures and considerably higher for nonelective procedures).

Abstract Rationale Surgical lung biopsy is often required for a confident multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF). Alternative, less-invasive biopsy methods, such as bronchoscopic lung cryobiopsy (BLC), are highly desirable. Objectives To address the impact of BLC on diagnostic confidence in the multidisciplinary diagnosis of IPF. Methods In this cross-sectional study we selected 117 patients with fibrotic interstitial lung disease without a typical usual interstitial pneumonia pattern on high-resolution computed tomography. All cases underwent lung biopsies: 58 were BLC, and 59 were surgical lung biopsy (SLB). Two clinicians, two radiologists, and two pathologists sequentially reviewed clinical-radiologic findings and biopsy results, recording at each step in the process their diagnostic impressions and confidence levels. Measurements and Main Results We observed a major increase in diagnostic confidence after the addition of BLC, similar to SLB (from 29 to 63%, P = 0.0003 and from 30 to 65%, P = 0.0016 of high confidence IPF diagnosis, in the BLC group and SLB group, respectively). The overall interobserver agreement in IPF diagnosis was similar for both approaches (BLC overall kappa, 0.96; SLB overall kappa, 0.93). IPF was the most frequent diagnosis (50 and 39% in the BLC and SLB group, respectively; P = 0.23). After the addition of histopathologic information, 17% of cases in the BLC group and 19% of cases in the SLB group, mostly idiopathic nonspecific interstitial pneumonia and hypersensitivity pneumonitis, were reclassified as IPF. Conclusions BLC is a new biopsy method that has a meaningful impact on diagnostic confidence in the multidisciplinary diagnosis of interstitial lung disease and may prove useful in the diagnosis of IPF. This study provides a robust rationale for future studies investigating the diagnostic accuracy of BLC compared with SLB.

AbstractIn 1963, the first bronchoscopic lung biopsy was performed. Less than 10 years later, the technique of transbronchial lung biopsy using a flexible bronchoscope was introduced into clinical practice, significantly reducing the rate of major complications and the rate of surgical lung biopsies in patients with diffuse parenchymal lung diseases. The diagnostic yield of transbronchial lung biopsy varies among various parenchymal lung diseases. In pulmonary sarcoidosis and lymphangitis carcinomatosa, a diagnosis can be obtained in up to 80% of patients. This method is considered inadequate, however, in identifying more complex histological patterns such as usual interstitial pneumonitis or nonspecific interstitial pneumonitis. Introduction of the ‘jumbo forceps’ and of a more ‘surgically oriented’ procedural setting (patients deeply sedated and intubated) allowed larger and more numerous lung specimens to be obtained without a significant increase of complications such as pneumothorax or bronchial bleeding. However, the possibility to obtain enough parenchymal tissue for a morphological diagnosis of complex patterns remained unmet. Recently, the use of cryoprobes has achieved a significant impact on this issue allowing to obtain large quantity of tissue. Recent studies document that with transbronchial cryobiopsies the diagnosis of usual interstitial pneumonitis can be made confidently by pathologists with a good inter‐observer agreement. Pneumothorax is the main complication (reported in up to one fourth of cases in some series); bronchial bleeding is easily controlled using Fogarty balloon. Transbronchial cryobiopsy is a promising new technique that may become a valid alternative to surgical lung biopsy in the near feature.