Search

Background Interstitial lung abnormalities (ILAs) reflect imaging features on lung CT scans that are compatible with (early) interstitial lung disease. Despite accumulating evidence regarding the incidence, risk factors, and prognosis of ILAs, the histopathologic correlates of ILAs remain elusive. Purpose To determine the correlation between radiologic and histopathologic findings in CT-defined ILAs in human lung explants. Materials and Methods Explanted lungs or lobes from participants with radiologically documented ILAs were prospectively collected from 2010 to 2021. These specimens were air-inflated, frozen, and scanned with CT and micro-CT (spatial resolution of 0.7 mm and 90 μm, respectively). Subsequently, the lungs were cut and sampled with core biopsies. At least five samples per lung underwent micro-CT and subsequent histopathologic assessment with semiquantitative remodeling scorings. Based on area-specific radiologic scoring, the association between radiologic and histopathologic findings was assessed. Results Eight lung explants from six donors (median age at explantation, 71 years [range, 60-83 years]; four men) were included (unused donor lungs, n = 4; pre-emptive lobectomy for oncologic indications, n = 2). Ex vivo CT demonstrated ground-glass opacification, reticulation, and bronchiectasis. Micro-CT and histopathologic examination demonstrated that lung abnormalities were frequently paraseptal and associated with fibrosis and lymphocytic inflammation. The histopathologic results showed varying degrees of fibrosis in areas that appeared normal on CT scans. Regions of reticulation on CT scans generally had greater fibrosis at histopathologic analysis. Vasculopathy and bronchiectasis were also often present at histopathologic examination of lungs with ILAs. Fully developed fibroblastic foci were rarely observed. Conclusion This study demonstrated direct histologic correlates of CT-defined interstitial lung abnormalities. © RSNA, 2022 Supplemental material is available for this article. See also the editorial by Jeudy in this issue.

Aims: Severe acute respiratory syndrome coronavirus-2 infection causes COVID-19, which in severe cases evokes life-threatening acute respiratory distress syndrome (ARDS). Transcriptome signatures and the functional relevance of non-vascular cell types (e.g. immune and epithelial cells) in COVID-19 are becoming increasingly evident. However, despite its known contribution to vascular inflammation, recruitment/invasion of immune cells, vascular leakage, and perturbed haemostasis in the lungs of severe COVID-19 patients, an in-depth interrogation of the endothelial cell (EC) compartment in lethal COVID-19 is lacking. Moreover, progressive fibrotic lung disease represents one of the complications of COVID-19 pneumonia and ARDS. Analogous features between idiopathic pulmonary fibrosis (IPF) and COVID-19 suggest partial similarities in their pathophysiology, yet, a head-to-head comparison of pulmonary cell transcriptomes between both conditions has not been implemented to date., Methods and Results: We performed single-nucleus RNA-sequencing on frozen lungs from 7 deceased COVID-19 patients, 6 IPF explant lungs, and 12 controls. The vascular fraction, comprising 38 794 nuclei, could be subclustered into 14 distinct EC subtypes. Non-vascular cell types, comprising 137 746 nuclei, were subclustered and used for EC-interactome analyses. Pulmonary ECs of deceased COVID-19 patients showed an enrichment of genes involved in cellular stress, as well as signatures suggestive of dampened immunomodulation and impaired vessel wall integrity. In addition, increased abundance of a population of systemic capillary and venous ECs was identified in COVID-19 and IPF. COVID-19 systemic ECs closely resembled their IPF counterparts, and a set of 30 genes was found congruently enriched in systemic ECs across studies. Receptor-ligand interaction analysis of ECs with non-vascular cell types in the pulmonary micro-environment revealed numerous previously unknown interactions specifically enriched/depleted in COVID-19 and/or IPF., Conclusions: This study uncovered novel insights into the abundance, expression patterns, and interactomes of EC subtypes in COVID-19 and IPF, relevant for future investigations into the progression and treatment of both lethal conditions., Competing Interests: Conflict of interest: A.D. received payments from FMC Belgium, and has a leadership/fiduciary role in the Belgian Society of Pathology (non-profit), and European Society of Pathology Nephropathology working group (non-profit). B.T. has a consulting role for ONO pharmaceutical and owns 10X genomics stocks. B.W. received payments from Hologic. L.J.C. received a research grant and consulting fees from MEDTRONIC. S.F. received support from Pfizer for congress attendance. W.W. received research grants and payment for lectures from Roche and Boehringer Ingelheim and a research grant from Galapagos. S.V. received consulting fees from Therakos and Boehringer Ingelheim. J.W. received investigator-initiated grants, consulting fees, speaker fees, and travel grants from Pfizer and Gilead., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Objectives: To investigate the effect of a LLETZ procedure on p16/Ki-67 dual stain, PAP cytology and HR-HPV test results on cervical cytology samples obtained prior to and 6 months after the procedure. Secondary aims are to assess dependency between test results at the time of follow-up and explore dual stain positivity rates according to known risk factors for persistence/recurrence of cervical intra-epithelial neoplasia (CIN)., Study Design: Prospective observational cohort study conducted in the Department of Gynaecology at the University Hospitals of Leuven, Belgium. All patients referred for a LLETZ procedure were invited to participate. A cervical cytology sample was obtained just prior to and 6 months after the procedure. Every sample was used for PAP staining (cytology), p16/Ki-67 dual staining (dual stain test, DST) and HR-HPV genotyping. Test results were compared between both timepoints using the McNemar test. Dependency was assessed cross-sectionally at the time of follow-up using a chi-squared test., Results: From the 110 participants originally included, 83 attended follow-up (75.5%). Mean duration of follow-up was 187.91 days (SD 21.47) and mean age was 41.4 years (SD 11.08). DST positivity rates were 70.9 and 30.1% prior to and 6 months after the procedure (p < 0.001). HR-HPV testing (positive or negative) and abnormal PAP cytology (evaluated at an ASCUS or worse threshold) showed a similar significant reduction in positivity rates (84.5 vs 42.2% and 72.7 vs 28.9%, respectively, p < 0.001). Results of all three assays showed high dependency at the time of follow-up (DST and PAP, PAP and HR-HPV test, DST and HR-HPV test-p values < 0.001). The highest proportion of positive DST results was seen in patients carrying HPV16 (84.6%), followed by any HR-HPV type (60%), those treated for CIN2 + (27.3%) and those with positive margins on the cone specimen (26.7%)., Conclusion: A LLETZ procedure results in a significant decrease in abnormal DST, PAP cytology and HR-HPV test results in this diverse cohort of patients. The highest proportion of abnormal DST results was seen in patients carrying HR-HPV at the time of follow-up, especially HPV 16., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The World Health Organization (WHO), the International Academy of Cytology, and the International Agency for Research on Cancer, with expert contributors from around the world, present an international approach to standardized reporting of pancreaticobiliary cytopathology. This reporting system is one of the first in a series from various body sites that mirror the WHO Classification of Tumours series and provides an evidence-based terminology system with associated risk of malignancy and diagnostic management recommendation per diagnostic category. The WHO Reporting System for Pancreaticobiliary Cytopathology (WHO system) revises the Papanicolaou Society of Cytopathology (PSC) system for Reporting Pancreaticobiliary Cytology published in 2015 and replaces the six-tiered system with a seven-tiered system: "insufficient/inadequate/nondiagnostic"; "benign (negative for malignancy)," "atypical," "pancreaticobiliary neoplasm of low risk/low grade," "pancreatic neoplasm of high risk/high grade," "suspicious for malignancy," and "malignant." The principal differences between the WHO and the PSC systems revolve around the classification of neoplasia. In the PSC system, there was a single category for "neoplastic" lesions that includes two groups, one for "benign neoplasms" [primarily serous cystadenoma] and one named "other," dominated by premalignant intraductal neoplasms (primarily intraductal papillary mucinous neoplasms) and low-grade malignant neoplasms [pancreatic neuroendocrine tumors (PanNETs) and solid pseudopapillary neoplasms (SPNs)]. In the WHO system, benign neoplasms with virtually no risk of malignancy are included in the "benign" category and low-grade malignancies (PanNET and SPN) are included in the "malignant" category, as per the WHO Classification of Digestive System Tumours, thus leaving in the "neoplasm" category primarily those noninvasive premalignant lesions of the ductal system. These neoplasms are divided by the cytomorphological grade of the epithelium into low risk/low-grade and high risk/high-grade, with distinctly different risks of malignancy. As with the PSC system, the WHO system advocates close correlation with imaging and encourages incorporation of ancillary testing into the final diagnosis, such as biochemical (CEA and amylase) and molecular testing of cyst fluid and bile duct brushings. Key diagnostic cytopathological features of specific lesions or neoplasms, ancillary studies for diagnostic and prognostic evaluation, and implications of diagnosis for patient care and management are discussed. In addition, the WHO system includes reporting and diagnostic management options that recognize the variations in the availability of diagnostic and prognostic ancillary testing modalities in low- and middle-income countries, where cytopathology is particularly useful and is increasingly available in the absence of histopathological services., (© 2022 S. Karger AG, Basel.)

Aims: Gene fusions assays are key for personalised treatments of advanced human cancers. Their implementation on cytological material requires a preliminary validation that may make use of cell line slides mimicking cytological samples. In this international multi-institutional study, gene fusion reference standards were developed and validated., Methods: Cell lines harbouring EML4 (13) -ALK (20) and SLC34A2 (4) -ROS1 (32) gene fusions were adopted to prepare reference standards. Eight laboratories (five adopting amplicon-based and three hybridisation-based platforms) received, at different dilution points two sets of slides (slide A 50.0%, slide B 25.0%, slide C 12.5% and slide D wild type) stained by Papanicolaou (Pap) and May Grunwald Giemsa (MGG). Analysis was carried out on a total of 64 slides., Results: Four (50.0%) out of eight laboratories reported results on all slides and dilution points. While 12 (37.5%) out of 32 MGG slides were inadequate, 27 (84.4%) out of 32 Pap slides produced libraries adequate for variant calling. The laboratories using hybridisation-based platforms showed the highest rate of inadequate results (13/24 slides, 54.2%). Conversely, only 10.0% (4/40 slides) of inadequate results were reported by laboratories adopting amplicon-based platforms., Conclusions: Reference standards in cytological format yield better results when Pap staining and processed by amplicon-based assays. Further investigation is required to optimise these standards for MGG stained cells and for hybridisation-based approaches., Competing Interests: Competing interests: UM has received personal fees (as consultant and/or speaker bureau) from Boehringer Ingelheim, Roche, MSD, Amgen, Thermo Fisher Scientifics, Eli Lilly, Diaceutics, GSK, Merck and Astra Zeneca, unrelated to the current work. Lukas Bubendorf has a consulting or advisory role with Astra Zeneca, AbbVie, Bayer, Boehringer Ingelheim, Eli Lilly, MSD, Pfizer, Takeda and F. Hoffmann-La Roche and has received research funding (institution) from F. Hoffmann-La Roche, MSD and Sanofi. PH reports personal fees (as advisor) from Roche, Astrazeneca, BMS, MSD, Pfizer, Bayer, Amgen, Illumina, Qiagen, Thermo Fisher Scientific, Biocartis, Ed Lilly, unrelated to the current work. SM-B has received personal fees (as consultant and/or speaker bureau) from Astra Zeneca, Roche, BMS, Novartis, GSK, MSD, Targos, Merck, unrelated to the current work. Spasenija Savic Prince received personal fees from MSD, Astra Zeneca, Boehringer Ingelheim, Roche, Pfizer, Bristol-Myers Squibb and Thermo Fisher Scientific, unrelated to the submitted work. EV has received personal fees (as consultant and/or speaker bureau) from Diaceutics, unrelated to the current work. GTr reports personal fees (as speaker bureau or advisor) from Roche, MSD, Pfizer, Boehringer Ingelheim, Eli Lilly, BMS, GSK, Menarini, AstraZeneca, Amgen and Bayer, unrelated to the current work. The other authors have nothing to disclose., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Remdesivir was the first antiviral drug to be approved for the treatment of severe COVID-19; followed by molnupiravir (another prodrug of a nucleoside analogue) and the protease inhibitor nirmatrelvir. Combination of antiviral drugs may result in improved potency and help to avoid or delay the development of resistant variants. We set out to explore the combined antiviral potency of GS-441524 (the parent nucleoside of remdesivir) and molnupiravir against SARS-CoV-2. In SARS-CoV-2 (BA.5) infected A549-Dual™ hACE2-TMPRSS2 cells, the combination resulted in an overall additive antiviral effect with a synergism at certain concentrations. Next, the combined effect was explored in Syrian hamsters infected with SARS-CoV-2 (Beta, B.1.351); treatment was started at the time of infection and continued twice daily for four consecutive days. At day 4 post-infection, GS-441524 (50 mg/kg, oral BID) and molnupiravir (150 mg/kg, oral BID) as monotherapy reduced infectious viral loads by 0.5 and 1.6 log 10 , respectively, compared to the vehicle control. When GS-441524 (50 mg/kg, BID) and molnupiravir (150 mg/kg, BID) were combined, infectious virus was no longer detectable in the lungs of 7 out of 10 of the treated hamsters (4.0 log 10 reduction) and titers in the other animals were reduced by ∼2 log 10 . The combined antiviral activity of molnupiravir which acts by inducing lethal mutagenesis and GS-441524, which acts as a chain termination appears to be highly effective in reducing SARS-CoV-2 replication/infectivity. The unexpected potent antiviral effect of the combination warrants further exploration as a potential treatment for COVID-19., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Abdelnabi, Maes, de Jonghe, Weynand and Neyts.)

We report a rare case of an endometriotic lung cyst in a 47-year woman with recurrent catamenial hemoptysis. Chest computed tomography (CT) obtained outside the menstruation in October 2019 revealed a cystic lesion (2.5 cm) located in the right inferior lobe near the distal esophagus and the inferior pulmonary vein. Compared to CT abdomen in May 2019, this lesion had increased with a larger volume and a thicker wall. An endometrial lung cyst was suspected as episodes of hemoptysis no longer occurred after initiating hormonal treatment with nomegestrol acetate. Exploratory video-assisted thoracoscopic surgery with wedge resection of the cyst was performed. Histopathologic examination confirmed the diagnosis of an endometriotic cystic lesion. Postoperative course was uneventful with no further symptoms since then.

Pleural mesothelioma (PM) is an aggressive malignancy with poor prognosis. Although histology and pathologic stage are important prognostic factors, better prognostic biomarkers are needed. The ribosomal protein S6 is a downstream target of the phosphatidylinositol 3-kinase (PI3K) pathway involved in protein synthesis and cell proliferation. In previous studies, low phosphorylated S6 (pS6) immunoreactivity was significantly correlated with longer progression-free survival (PFS) and overall survival (OS) in PM patients. We aimed to correlate pS6 expression to clinical data in a large multi-centre PM cohort as part of the European Thoracic Oncology Platform (ETOP) Mesoscape project. Tissue Micro Arrays (TMAs) of PM were constructed and expression of pS6 was evaluated by a semi-quantitatively aggregate H-score. Expression results were correlated to patient characteristics as well as OS/PFS. pS6 IHC results of 364 patients from 9 centres, diagnosed between 1999 and 2017 were available. The primary histology of included tumours was epithelioid (70.3%), followed by biphasic (24.2%) and sarcomatoid (5.5%). TMAs included both treatment-naïve and tumour tissue taken after induction chemotherapy. High pS6 expression (181 patients with H-score>1.41) was significantly associated with less complete resection. In the overall cohort, OS/PFS were not significantly different between pS6-low and pS6-high patients. In a subgroup analysis non-epithelioid (biphasic and sarcomatoid) patients with high pS6 expression showed a significantly shorter OS (p < 0.001, 10.7 versus 16.9 months) and PFS (p < 0.001, 6.2 versus 10.8 months). In subgroup analysis, in non-epithelioid PM patients high pS6 expression was associated with significantly shorter OS and PFS. These exploratory findings suggest a clinically relevant PI3K pathway activation in non-epithelioid PM which might lay the foundation for future targeted treatment strategies., (© 2022. The Author(s).)

Current COVID-19 vaccines are based on prototypic spike sequences from ancestral 2019 SARS-CoV-2 strains. However, the ongoing pandemic is fueled by variants of concern (VOC) escaping vaccine-mediated protection. Here we demonstrate how immunization in hamsters using prototypic spike expressed from yellow fever 17D (YF17D) as vector blocks ancestral virus (B lineage) and VOC Alpha (B.1.1.7) yet fails to fully protect from Beta (B.1.351). However, the same YF17D vectored vaccine candidate with an evolved antigen induced considerably improved neutralizing antibody responses against VOCs Beta, Gamma (P.1) and the recently predominant Omicron (B.1.1.529), while maintaining immunogenicity against ancestral virus and VOC Delta (B.1.617.2). Thus vaccinated animals resisted challenge by all VOCs, including vigorous high titre exposure to the most difficult to cover Beta, Delta and Omicron variants, eliminating detectable virus and markedly improving lung pathology. Finally, vaccinated hamsters did not transmit Delta variant to non-vaccinated cage mates. Overall, our data illustrate how current first-generation COVID-19 vaccines may need to be updated to maintain efficacy against emerging VOCs and their spread at community level., (© 2022. The Author(s).)

Competing Interests: Disclosure: There is no conflict of interest or other disclosures.

Since a detailed inventory of endothelial cell (EC) heterogeneity in breast cancer (BC) is lacking, here we perform single cell RNA-sequencing of 26,515 cells (including 8433 ECs) from 9 BC patients and compare them to published EC taxonomies from lung tumors. Angiogenic ECs are phenotypically similar, while other EC subtypes are different. Predictive interactome analysis reveals known but also previously unreported receptor-ligand interactions between ECs and immune cells, suggesting an involvement of breast EC subtypes in immune responses. We also identify a capillary EC subtype (LIPEC (Lipid Processing EC)), which expresses genes involved in lipid processing that are regulated by PPAR-γ and is more abundant in peri-tumoral breast tissue. Retrospective analysis of 4648 BC patients reveals that treatment with metformin (an indirect PPAR-γ signaling activator) provides long-lasting clinical benefit and is positively associated with LIPEC abundance. Our findings warrant further exploration of this LIPEC/PPAR-γ link for BC treatment., (© 2022. The Author(s).)

Background: The live-attenuated yellow fever vaccine YF17D holds great promise as alternative viral vector vaccine platform, showcased by our previously presented potent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine candidate YF-S0. Besides protection from SARS-CoV-2, YF-S0 also induced strong yellow fever virus (YFV)-specific immunity, suggestive for full dual activity. A vaccine concomitantly protecting from SARS-CoV-2 and YFV would be of great benefit for those living in YFV-endemic areas with limited access to current SARS-CoV-2 vaccines. However, for broader applicability, pre-existing vector immunity should not impact the potency of such YF17D-vectored vaccines., Methods: The immunogenicity and efficacy of YF-S0 against YFV and SARS-CoV-2 in the presence of strong pre-existing YFV immunity were evaluated in mouse and hamster challenge models., Findings: Here, we show that a single dose of YF-S0 is sufficient to induce strong humoral and cellular immunity against YFV as well as SARS-CoV-2 in mice and hamsters; resulting in full protection from vigorous YFV challenge in either model; in mice against lethal intracranial YF17D challenge, and in hamsters against viscerotropic infection and liver disease following challenge with highly pathogenic hamster-adapted YFV-Asibi strain. Importantly, strong pre-existing immunity against the YF17D vector did not interfere with subsequent YF-S0 vaccination in mice or hamsters; nor with protection conferred against SARS-CoV-2 strain B1.1.7 (Alpha variant) infection in hamsters., Interpretation: Our findings warrant the development of YF-S0 as dual SARS-CoV-2 and YFV vaccine. Contrary to other viral vaccine platforms, use of YF17D does not suffer from pre-existing vector immunity., Funding: Stated in the acknowledgments., Competing Interests: Declaration of interests The authors have nothing to disclose., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Ancestral severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lacks the intrinsic ability to bind to the mouse ACE2 receptor, and therefore establishment of SARS-CoV-2 mouse models has been limited to the use of mouse-adapted viruses or genetically modified mice. Interestingly, some of the variants of concern, such as the Beta B.1.351 variant, show an improved binding to the mouse receptor and hence better replication in different wild-type (WT) mouse species. Here, we describe the establishment of a SARS-CoV-2 Beta B.1.351 variant infection model in male SCID mice as a tool to assess the antiviral efficacy of potential SARS-CoV-2 small-molecule inhibitors. Intranasal infection of male SCID mice with 10 5 50% tissue culture infective doses (TCID 50 ) of the Beta B.1.351 variant resulted in high viral loads in the lungs and moderate signs of lung pathology on day 3 postinfection. Treatment of infected mice with the antiviral drugs molnupiravir (200 mg/kg, twice a day [BID]) or nirmatrelvir (300 mg/kg, BID) for 3 consecutive days significantly reduced the infectious virus titers in the lungs by 2 and 3.9 log 10 TCID 50 /mg of tissue, respectively, and significantly improved lung pathology. Together, these data demonstrate the validity of this SCID mouse Beta B.1.351 variant infection model as a convenient preclinical model for assessment of potential activity of antivirals against SARS-CoV-2. IMPORTANCE Unlike the ancestral SARS-CoV-2 strain, the Beta (B.1.351) variant of concern has been reported to replicate to some extent in WT mice (C57BL/6 and BALB/c). We demonstrate here that infection of SCID mice with the Beta variant resulted in high viral loads in the lungs on day 3 postinfection. Treatment of infected mice with molnupiravir or nirmatrelvir for 3 consecutive days markedly reduced the infectious virus titers in the lungs and improved lung pathology. The SARS-CoV2 SCID mouse infection model, which is ideally suited for antiviral studies, offers an advantage in comparison to other SARS-CoV2 mouse models, in that there is no need for the use of mouse-adapted virus strains or genetically modified mice. Mouse models also have advantages over hamster models because (i) lower amounts of test drugs are needed, (ii) more animals can be housed in a cage, and (iii) reagents to analyze mouse samples are more readily available than those for hamsters.

The coronavirus spike glycoprotein attaches to host receptors and mediates viral fusion. Using a broad screening approach, we isolated seven monoclonal antibodies (mAbs) that bind to all human-infecting coronavirus spike proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune donors. These mAbs recognize the fusion peptide and acquire affinity and breadth through somatic mutations. Despite targeting a conserved motif, only some mAbs show broad neutralizing activity in vitro against alpha- and betacoronaviruses, including animal coronaviruses WIV-1 and PDF-2180. Two selected mAbs also neutralize Omicron BA.1 and BA.2 authentic viruses and reduce viral burden and pathology in vivo. Structural and functional analyses showed that the fusion peptide-specific mAbs bound with different modalities to a cryptic epitope hidden in prefusion stabilized spike, which became exposed upon binding of angiotensin-converting enzyme 2 (ACE2) or ACE2-mimicking mAbs.

In the absence of drugs to treat or prevent COVID-19, drug repurposing can be a valuable strategy. Despite a substantial number of clinical trials, drug repurposing did not deliver on its promise. While success was observed with some repurposed drugs (e.g., remdesivir, dexamethasone, tocilizumab, baricitinib), others failed to show clinical efficacy. One reason is the lack of clear translational processes based on adequate preclinical profiling before clinical evaluation. Combined with limitations of existing in vitro and in vivo models, there is a need for a systematic approach to urgent antiviral drug development in the context of a global pandemic. We implemented a methodology to test repurposed and experimental drugs to generate robust preclinical evidence for further clinical development. This translational drug development platform comprises in vitro, ex vivo, and in vivo models of SARS-CoV-2, along with pharmacokinetic modeling and simulation approaches to evaluate exposure levels in plasma and target organs. Here, we provide examples of identified repurposed antiviral drugs tested within our multidisciplinary collaboration to highlight lessons learned in urgent antiviral drug development during the COVID-19 pandemic. Our data confirm the importance of assessing in vitro and in vivo potency in multiple assays to boost the translatability of pre-clinical data. The value of pharmacokinetic modeling and simulations for compound prioritization is also discussed. We advocate the need for a standardized translational drug development platform for mild-to-moderate COVID-19 to generate preclinical evidence in support of clinical trials. We propose clear prerequisites for progression of drug candidates for repurposing into clinical trials. Further research is needed to gain a deeper understanding of the scope and limitations of the presented translational drug development platform.

Nelfinavir is an HIV protease inhibitor that has been widely prescribed as a component of highly active antiretroviral therapy, and has been reported to exert in vitro antiviral activity against SARS-CoV-2. We here assessed the effect of Nelfinavir in a SARS-CoV-2 infection model in hamsters. Despite the fact that Nelfinavir, [50 mg/kg twice daily (BID) for four consecutive days], did not reduce viral RNA load and infectious virus titres in the lung of infected animals, treatment resulted in a substantial improvement of SARS-CoV-2-induced lung pathology. This was accompanied by a dense infiltration of neutrophils in the lung interstitium which was similarly observed in non-infected hamsters. Nelfinavir resulted also in a marked increase in activated neutrophils in the blood, as observed in non-infected animals. Although Nelfinavir treatment did not alter the expression of chemoattractant receptors or adhesion molecules on human neutrophils, in vitro migration of human neutrophils to the major human neutrophil attractant CXCL8 was augmented by this protease inhibitor. Nelfinavir appears to induce an immunomodulatory effect associated with increasing neutrophil number and functionality, which may be linked to the marked improvement in SARS-CoV-2 lung pathology independent of its lack of antiviral activity. Since Nelfinavir is no longer used for the treatment of HIV, we studied the effect of two other HIV protease inhibitors, namely the combination Lopinavir/Ritonavir (Kaletra™) in this model. This combination resulted in a similar protective effect as Nelfinavir against SARS-CoV2 induced lung pathology in hamsters., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Aim: Next generation sequencing (NGS) represents a key diagnostic tool to identify clinically relevant gene alterations for treatment-decision making in cancer care. However, the complex manual workflow required for NGS has limited its implementation in routine clinical practice. In this worldwide study, we validated the clinical performance of the TargetPlex FFPE-Direct DNA Library Preparation Kit for NGS analysis. Impressively, this new assay obviates the need for separate, labour intensive and time-consuming pre-analytical steps of DNA extraction, purification and isolation from formalin-fixed paraffin embedded (FFPE) specimens in the NGS workflow., Methods: The TargetPlex FFPE-Direct DNA Library Preparation Kit, which enables NGS analysis directly from FFPE, was specifically developed for this study by TargetPlex Genomics Pleasanton, California. Eleven institutions agreed to take part in the study coordinated by the Molecular Cytopathology Meeting Group (University of Naples Federico II, Naples, Italy). All participating institutions received a specific Library Preparation Kit to test eight FFPE samples previously assessed with standard protocols. The analytical parameters and mutations detected in each sample were then compared with those previously obtained with standard protocols., Results: Overall, 92.8% of the samples were successfully analysed with the TargetPlex FFPE-Direct DNA Library Preparation Kit on Thermo Fisher Scientific and Illumina platforms. Altogether, in comparison with the standard workflow, the TargetPlex FFPE-Direct DNA Library Preparation Kit was able to detect 90.5% of the variants., Conclusion: The TargetPlex FFPE-Direct DNA Library Preparation Kit combined with the SiRe panel constitutes a convenient, practical and robust cost-saving solution for FFPE NGS analysis in routine practice., Competing Interests: Competing interests: UM has received personal fees (as consultant and/or speaker bureau) from Boehringer Ingelheim, Roche, MSD, Amgen, Thermo Fisher Scientifics, Diaceutics, GSK, Merck and AstraZeneca, unrelated to the current work. LB is has a consulting or advisory role with AstraZeneca, AbbVie, Bayer, Boehringer Ingelheim, Eli Lilly, MSD, Pfizer, Takeda and F. Hoffmann-La Roche, and has received research funding (institution) from F. Hoffmann-La Roche, MSD and Sanofi. PH reports personal fees (as advisor) from Roche, Astrazeneca, BMS, MSD, Pfizer, Bayer, Amgen, Illumina, Qiagen, Thermo Fisher Scientific, Biocartis, Ed Lilly, unrelated to the current work. MI reports personal fees (as speaker bureau) from Roche, Merck & Co, AstraZeneca, Bristol-Myers Squibb and Boehringer-Ingelheim, unrelated to the current work. GR is the coinventor of the intellectual property used in the background noise suppression aspects of the TargePlex FFPE-Direct NGS Library Preparation Kit developed in collaboration with SenseCare Medicals. AR reports personal fees from Bristol, Pfizer, Bayer, Kyowa Kirin, Ambrosetti for advisory board activity and speaker honorarium from Roche Diagnostic speaker honorarium, unrelated to the submitted work. SS received personal fees from MSD, Astra Zeneca, Boehringer Ingelheim, Roche, Pfizer, Bristol-Myers Squibb and Thermo Fisher Scientific, unrelated to the submitted work. TX is an employee and affiliate with SenseCare Medicals. GTroncone reports personal fees (as speaker bureau or advisor) from Roche, MSD, Pfizer and Bayer, unrelated to the current work.The other authors have nothing to disclose., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To further evaluate the value of a standardized method to analyze vitreous samples using the Cellient® automated cell block system in the diagnosis of unsolved uveitis., Methods: Six hundred sixty-four pure vitreous samples obtained from patients with unsolved uveitis between March 2012 and May 2018 at University Hospitals Leuven, fixed in PreservCyt® and processed by the Cellient tissue processor, were included in the study., Results: n 86.3% of the cases, sufficient material was found for diagnosis. A diagnosis of acute inflammation was made in 20.2% of the cases. In 34.0% of the cases, the diagnosis was chronic active inflammation; in 26.5%, low-grade inflammation; and in 5.6%, a malignant process., Conclusion: Our standardized protocol can be used to diagnose endophthalmitis, lymphoma, granulomatous disease, inactive and storage disease, and metastatic infiltration. Cellient analysis of vitreous specimens had a diagnostic yield of 86.3% in unsolved uveitis cases.

Background: Although most guidelines suggest performing a positron emission tomography/computed tomography (PET/CT) with somatostatin receptor (SSTR) ligands for staging of pulmonary carcinoid tumours (PC), only a limited number of studies have evaluated the role of this imaging tool in this specific patient population. The preoperative differentiation between typical carcinoid (TC) and atypical carcinoid (AC) and the extent of dissemination (N/M status) are crucial factors for treatment allocation and prognosis of these patients. Therefore, we performed a pathology-based retrospective analysis of the value of SSTR PET/CT in tumour grading and detection of nodal and metastatic involvement of PC and compared this with the previous literature and with [ 18 F]FDG PET/CT in a subgroup of patients., Methods: SSTR PET/CT scans performed between January 2007 and May 2020 in the context of PC were included. If available, [ 18 F]FDG PET/CT images were also evaluated. The maximum standardized uptake (SUV max ) values of the primary tumour, of the pathologically examined hilar and mediastinal lymph node stations, as well as of the distant metastases, were recorded. Tumoural SUV max values were related to the tumour type (TC versus AC) for both SSTR and [ 18 F]FDG PET/CT in diagnosing and differentiating both tumour types. Nodal SUV max values were compared to the pathological status (N + versus N - ) to evaluate the diagnostic accuracy of SSTR PET/CT in detecting lymph node involvement. Finally, a mixed model analysis of all pathologically proven distant metastatic lesions was performed., Results: A total of 86 SSTR PET/CT scans performed in 86 patients with PC were retrospectively analysed. [ 18 F]FDG PET/CT was available in 46 patients. Analysis of the SUV max values in the primary tumour showed significantly higher SSTR uptake in TC compared with AC (median SUV max 18.4 vs 3.8; p = 0.003) and significantly higher [ 18 F]FDG uptake in AC compared to TC (median SUV max 5.4 vs 3.5; p = 0.038). Receiver operating characteristic (ROC) curve analysis resulted in an area under the curve (AUC) of 0.78 for the detection of TC on SSTR PET/CT and of 0.73 for the detection of AC on [ 18 F]FDG PET/CT. A total of 267 pathologically evaluated hilar and mediastinal lymph node stations were analysed. ROC analysis of paired SSTR/[ 18 F]FDG SUV max values for the detection of metastasis of TC in 83 lymph node stations revealed an AUC of 0.91 for SSTR PET/CT and of 0.74 for [ 18 F]FDG PET/CT (difference 0.17; 95% confidence interval - 0.03 to 0.38; p = 0.10). In a sub-cohort of 10 patients with 12 distant lesions that were pathologically examined due to a suspicious aspect on SSTR PET/CT, a positive predictive value (PPV) of 100% was observed., Conclusion: Our findings confirm the higher SSTR ligand uptake in TC compared to AC and vice versa for [ 18 F]FDG uptake. More importantly, we found a good diagnostic performance of SSTR PET/CT for the detection of hilar and mediastinal lymph node metastases of TC. Finally, a PPV of 100% for SSTR PET/CT was found in a small sub-cohort of patients with pathologically investigated distant metastatic lesions. Taken together, SSTR PET/CT has a very high diagnostic value in the TNM assessment of pulmonary carcinoids, particularly in TC, which underscores its position in European guidelines., (© 2022. The Author(s).)

Background: In a previous worldwide survey, the authors showed a drastic reduction in the number of cytological specimens processed during the coronavirus disease 2019 "lockdown" period along with an increase in malignancy rates. To assess the continued impact of the pandemic on cytological practices around the world, they undertook a second follow-up worldwide survey collecting data from the post-lockdown period (2020)., Methods: Participants were asked to provide data regarding their cytopathology activity during the first 12 weeks of their respective national post-lockdown period (2020), which ranged from April 4 to October 31. Differences between the post-lockdown period and the corresponding 2019 period were evaluated, and the authors specifically focused on rates of malignant diagnoses., Results: A total of 29 respondents from 17 countries worldwide joined the survey. Overall, a lower number of cytological specimens (n = 236,352) were processed in comparison with the same period in 2019 (n = 321,466) for a relative reduction of 26.5%. The overall malignancy rate showed a statistically significant increase (12,442 [5.26%] vs 12,882 [4.01%]; P < .001) during the same time period. Similar results were obtained if both malignancy and suspicious for malignancy rates were considered together (15,759 [6.58%] vs 16,011 [4.98%]; P < .001)., Conclusions: The data showed a persistent reduction in the cytological specimen volume during the post-lockdown period (2020). However, the relative increase in the cytological workload in the late part of the post-lockdown is a promising finding of a slow return to normality., (© 2022 American Cancer Society.)

Objectives: Targeted RNA-based Next-Generation Sequencing (tRNA-seq) is increasingly being used in molecular diagnostics for gene fusion detection in non-small cell lung cancer (NSCLC). However, few data support its clinical application for the detection of single nucleotide variants (SNVs) and small insertions/deletions. In this study, we evaluated the performance of tRNA-seq using Archer FusionPlex for simultaneous detection of actionable gene fusions, splice variants, SNVs and indels in formalin-fixed, paraffin-embedded NSCLC tissue., Materials and Methods: A total of 126 NSCLC samples, including 20 validation samples and 106 diagnostic cases, were analyzed by targeted DNA-based Next-Generation Sequencing (tDNA-seq) followed by tRNA-seq., Results: All 28 SNVs and indels in the validation set, and 34 out of 35 mutations in the diagnostic set were identified by tRNA-seq. The only mutation undetected by tRNA-seq, ERBB2 p.(Ser310Tyr), was not included in the current Archer panel design. tRNA-seq revealed one additional BRAF p.(Val600Glu) mutation not found by tDNA-seq. SNVs and indels were correctly called by the vendor supplied software, except for ERBB2 duplication p.(Tyr772&#95;A775dup) which was only detected by an additional in-house developed bio-informatics pipeline. Variant allelic frequency (VAF) values were generally higher at the expression level compared to the genomic level (range 6-96% for tRNA-seq versus 6-61% for tDNA-seq) and low VAF mutations in DNA (6-8% VAF) were all confirmed by tRNA-seq. Finally, tRNA-seq additionally identified a driver fusion or splice variant in 10 diagnostic NSCLC samples including one MET exon 14 skipping variant not detected by tDNA-seq., Conclusion: Our results demonstrate that tRNA-seq can be implemented in a diagnostic setting as an efficient strategy for simultaneous detection of actionable gene fusions, splice variants, SNVs and indels in NSCLC provided that adequate RNA-seq analysis tools are available, especially for the detection of indels. This approach allows upfront identification of currently recommended targetable molecular alterations in NSCLC samples., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Ivermectin, an FDA-approved antiparasitic drug, has been reported to have in vitro activity against SARS-CoV-2. Increased off-label use of ivermectin for COVID-19 has been reported. We here assessed the effect of ivermectin in Syrian hamsters infected with the SARS-CoV-2 Beta (B.1.351) variant. Infected animals received a clinically relevant dose of ivermectin (0.4 mg/kg subcutaneously dosed) once daily for four consecutive days after which the effect was quantified. Ivermectin monotherapy did not reduce lung viral load and even significantly worsened SARS-CoV-2-induced lung pathology. Additionally, it did not potentiate the activity of molnupiravir (Lagevrio TM ) when combined with this drug. This study contributes to the growing body of evidence that ivermectin does not result in a beneficial effect in the treatment of COVID-19. These findings are important given the increasing, dangerous off-label use of ivermectin for the treatment of COVID-19.

To control the coronavirus disease 2019 (COVID-19) pandemic and the emergence of different variants of concern (VoCs), novel vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed. In this study, we report the potent immunogenicity and efficacy induced in hamsters by a vaccine candidate based on a modified vaccinia virus Ankara (MVA) vector expressing a human codon optimized full-length SARS-CoV-2 spike (S) protein (MVA-S). Immunization with one or two doses of MVA-S elicited high titers of S- and receptor-binding domain (RBD)-binding IgG antibodies and neutralizing antibodies against parental SARS-CoV-2 and VoC alpha, beta, gamma, delta, and omicron. After SARS-CoV-2 challenge, MVA-S-vaccinated hamsters showed a significantly strong reduction of viral RNA and infectious virus in the lungs compared to the MVA-WT control group. Moreover, a marked reduction in lung histopathology was also observed in MVA-S-vaccinated hamsters. These results favor the use of MVA-S as a potential vaccine candidate for SARS-CoV-2 in clinical trials., Competing Interests: Authors DM, EP and ER were employed by the company Biofabri. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Boudewijns, Pérez, Lázaro-Frías, Van Looveren, Vercruysse, Thibaut, Weynand, Coelmont, Neyts, Astorgano, Montenegro, Puentes, Rodríguez, Dallmeier, Esteban and García-Arriaza.)

There is an urgent need for potent and selective antivirals against SARS-CoV-2. Pfizer developed PF-07321332 (PF-332), a potent inhibitor of the viral main protease (Mpro, 3CLpro) that can be dosed orally and that is in clinical development. We here report that PF-332 exerts equipotent in vitro activity against the four SARS-CoV-2 variants of concerns (VoC) and that it can completely arrest replication of the alpha variant in primary human airway epithelial cells grown at the air-liquid interface. Treatment of Syrian Golden hamsters with PF-332 (250 mg/kg, twice daily) completely protected the animals against intranasal infection with the beta (B.1.351) and delta (B.1.617.2) SARS-CoV-2 variants. Moreover, treatment of SARS-CoV-2 (B.1.617.2) infected animals with PF-332 completely prevented transmission to untreated co-housed sentinels., (© 2022. The Author(s).)

The emergence of SARS-CoV-2 variants of concern (VoCs) has exacerbated the COVID-19 pandemic. End of November 2021, a new SARS-CoV-2 variant namely the omicron (B.1.1.529) emerged. Since this omicron variant is heavily mutated in the spike protein, WHO classified this variant as the 5th variant of concern (VoC). We previously demonstrated that the ancestral strain and the other SARS-CoV-2 VoCs replicate efficiently in and cause a COVID19-like pathology in Syrian hamsters. We here wanted to explore the infectivity of the omicron variant in comparison to the ancestral D614G strain in the hamster model. Strikingly, in hamsters that had been infected with the omicron variant, a 3 log 10 lower viral RNA load was detected in the lungs as compared to animals infected with D614G and no infectious virus was detectable in this organ. Moreover, histopathological examination of the lungs from omicron-infected hamsters revealed no signs of peri-bronchial inflammation or bronchopneumonia., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: The neurotrophic tropomyosin-related kinase (NTRK) genes encode the tropomyosin receptor kinases (TRKs). Patients with solid tumors harboring an oncogenic NTRK fusion are eligible for treatment with TRK inhibitors. NTRK fusion is often associated with TRK overexpression. Pan-TRK immunohistochemistry (IHC) is used to screen for NTRK fusions, but immunoreactivity patterns are poorly defined., Methods: Data on pan-TRK immunoreactivity patterns in 2,669 solid tumors (comprising carcinomas, sarcomas, and melanocytic lesions) were retrospectively collected by nine laboratories and comprised tumor type, percentage of pan-TRK-positive tumor cells, staining intensity, cytoplasmic, membrane and/or nuclear staining pattern, and the presence or absence of NTRK fusion., Results: Overall, 2,457 tumors (92%) were pan-TRK negative and 212 neoplasms (8%) were pan-TRK positive. Twenty-two pan-TRK-positive tumors (0.8%) harbored an NTRK fusion, representing 10% of all pan-TRK-positive tumors. Cytoplasmic immunoreactivity was most often observed, followed by membrane immunoreactivity. Nuclear pan-TRK positivity was least frequent, but was most often (33%) associated with NTRK fusion., Conclusion: Pan-TRK IHC can be used to screen for NTRK fusions, especially in commonly diagnosed solid tumors with low NTRK fusion prevalence. In case of pan-TRK immunoreactivity, regardless of its intensity and tumor cell percentage, subsequent molecular tests should be performed to formally confirm the presence or absence of NTRK fusions., (© 2022 The Author(s). Published by S. Karger AG, Basel.)

The SARS-CoV-2 pandemic has impacted the health of humanity after the outbreak in Hubei, China in late December 2019. Ever since, it has taken unprecedented proportions and rapidity causing over a million fatal cases. Recently, a robust Syrian golden hamster model recapitulating COVID-19 was developed in search for effective therapeutics and vaccine candidates. However, overt clinical disease symptoms were largely absent despite high levels of virus replication and associated pathology in the respiratory tract. Therefore, we used micro-computed tomography (μCT) to longitudinally visualize lung pathology and to preclinically assess candidate vaccines. μCT proved to be crucial to quantify and noninvasively monitor disease progression, to evaluate candidate vaccine efficacy, and to improve screening efforts by allowing longitudinal data without harming live animals. Here, we give a comprehensive guide on how to use low-dose high-resolution μCT to follow-up SARS-CoV-2-induced disease and test the efficacy of COVID-19 vaccine candidates in hamsters. Our approach can likewise be applied for the preclinical assessment of antiviral and anti-inflammatory drug treatments in vivo., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Bronchiolitis obliterans syndrome (BOS) is considered an airway-centered disease, with bronchiolitis obliterans (BO) as pathologic hallmark. However, the histologic spectrum of pure clinical BOS remains poorly characterized. We provide the first in-depth histopathologic description of well-characterized BOS patients and patients without chronic lung allograft dysfunction (CLAD), defined according to the recent consensus guidelines. Explant lung tissue from 52 clinically-defined BOS and 26 non-CLAD patients (collected 1993-2018) was analyzed for histologic parameters, including but not limited to airway lesions, vasculopathy and fibrosis. In BOS, BO lesions were evident in 38 (73%) patients and varied from concentric sub-epithelial fibrotic BO to inflammatory BO, while 10/14 patients without BO displayed 'vanishing airways', defined by a discordance between arteries and airways. Chronic vascular abnormalities were detected in 22 (42%) patients. Ashcroft fibrosis scores revealed a median of 43% (IQR: 23-69) of normal lung parenchyma per patient; 26% (IQR: 18-37) of minimal alveolar fibrous thickening; and 11% (IQR: 4-18) of moderate alveolar thickening without architectural damage. Patchy areas of definite fibrotic damage to the lung structure (i.e., Ashcroft score ≥5) were present in 28 (54%) patients. Fibrosis was classified as bronchocentric ( n = 21/28, 75%), paraseptal ( n = 17/28, 61%) and subpleural ( n = 15/28, 54%). In non-CLAD patients, BO lesions were absent, chronic vascular abnormalities present in 1 (4%) patient and mean Ashcroft scores were significantly lower compared to BOS ( p = 0.0038) with 78% (IQR: 64-88) normally preserved lung parenchyma. BOS explant lungs revealed evidence of various histopathologic findings, including vasculopathy and fibrotic changes, which may contribute to the pathophysiology of BOS.

Broadly neutralizing antibodies are an important treatment for individuals with coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Antibody-based therapeutics are also essential for pandemic preparedness against future Sarbecovirus outbreaks. Camelid-derived single domain antibodies (VHHs) exhibit potent antimicrobial activity and are being developed as SARS-CoV-2–neutralizing antibody-like therapeutics. Here, we identified VHHs that neutralize both SARS-CoV-1 and SARS-CoV-2, including now circulating variants. We observed that the VHHs bound to a highly conserved epitope in the receptor binding domain of the viral spike protein that is difficult to access for human antibodies. Structure-guided molecular modeling, combined with rapid yeast-based prototyping, resulted in an affinity enhanced VHH-human immunoglobulin G1 Fc fusion molecule with subnanomolar neutralizing activity. This VHH-Fc fusion protein, produced in and purified from cultured Chinese hamster ovary cells, controlled SARS-CoV-2 replication in prophylactic and therapeutic settings in mice expressing human angiotensin converting enzyme 2 and in hamsters infected with SARS-CoV-2. These data led to affinity-enhanced selection of the VHH, XVR011, a stable anti–COVID-19 biologic that is now being evaluated in the clinic.

Objectives: Numerous studies on malignant mesothelioma (MM) highlight the prognostic importance of histologic subtype, nuclear grade, and necrosis. This study compares these parameters in paired biopsy and resection specimens of pleural MM., Methods: Histologic subtype, percentage of epithelioid morphology, nuclear grade, and the presence or absence of necrosis were compared in 429 paired biopsies and resection specimens of pleural MM from 19 institutions., Results: Histologic subtype was concordant in 81% of cases (κ = 0.58). When compared with resection specimens, epithelioid morphology at biopsy had a positive predictive value (PPV) of 78.9% and a negative predictive value (NPV) of 93.5%; sarcomatoid morphology showed high PPV (92.9%) and NPV (99.3%), and biphasic morphology PPV was 89.7% and NPV was 79.7%. Agreement of the percentage of epithelioid morphology was fair (κ = 0.27). Nuclear grade and necrosis were concordant in 75% (κ = 0.59) and 81% (κ = 0.53) of cases, respectively. Nuclear grade showed moderate (κ = 0.53) and substantial (κ = 0.67) agreement from patients with and without neoadjuvant therapy, respectively, and necrosis showed moderate (κ = 0.47 and κ = 0.60) agreement, respectively, in the same subsets of paired specimens., Conclusions: Paired biopsy-resection specimens from pleural MM show overall moderate agreement in pathologic parameters. These findings may help guide postbiopsy management and triage of patients with MM., (© American Society for Clinical Pathology, 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Randomized placebo-controlled trials demonstrated the efficacy of antifibrotic treatment in non-IPF progressive fibrosing ILD (fILD). Currently, there is no consensus on how progression should be defined and clinical data of non-IPF fILD patients in a real-world setting are scarce. Non-IPF fILD patients presenting at the University Hospitals Leuven between 2012 and 2016 were included. Different definitions of progression according to the selection criteria of the INBUILD, RELIEF and the uILD study were retrospectively evaluated at every hospital visit. Univariate and multivariate analyses were performed to identify predictors of progression and mortality. The study cohort comprised 120 patients; 68.3%, 54.2% and 65.8% had progressive disease based on the INBUILD, RELIEF and uILD study, respectively. A large overlap of progressive fILD patients according to the different clinical trials was observed. Median transplant-free survival time of progressive fILD patients was 3.9, 3.9, 3.8 years and the median time-to-progression after diagnosis was 2.0, 3.1 and 2.3 years according to the INBUILD, RELIEF and uILD study, respectively. We identified several predictors of mortality, but only an underlying diagnosis of HP and uILD was independently associated with progression. Our data show a high prevalence of progressive fibrosis among non-IPF fILD patients and a discrepancy between predictors of mortality and progression. Mortality rate in fILD is high and the identification of progressive disease is only made late during the disease course. Moreover, future treatment decisions will be based upon disease behavior. Therefore, more predictors of progressive disease are needed to guide treatment decisions in the future., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Favipiravir and Molnupiravir, orally available antivirals, have been reported to exert antiviral activity against SARS-CoV-2. First efficacy data have been recently reported in COVID-19 patients., Methods: We here report on the combined antiviral effect of both drugs in a SARS-CoV-2 Syrian hamster infection model. The infected hamsters were treated twice daily with the vehicle (the control group) or a suboptimal dose of each compound or a combination of both compounds., Findings: When animals were treated with a combination of suboptimal doses of Molnupiravir and Favipiravir at the time of infection, a marked combined potency at endpoint is observed. Infectious virus titers in the lungs of animals treated with the combination are reduced by ∼5 log10 and infectious virus are no longer detected in the lungs of >60% of treated animals. When start of treatment was delayed with one day a reduction of titers in the lungs of 2.4 log10 was achieved. Moreover, treatment of infected animals nearly completely prevented transmission to co-housed untreated sentinels. Both drugs result in an increased mutation frequency of the remaining viral RNA recovered from the lungs of treated animals. In the combo-treated hamsters, an increased frequency of C-to-T mutations in the viral RNA is observed as compared to the single treatment groups which may explain the pronounced antiviral potency of the combination., Interpretation: Our findings may lay the basis for the design of clinical studies to test the efficacy of the combination of Molnupiravir/Favipiravir in the treatment of COVID-19., Funding: stated in the acknowledgment., Competing Interests: Declaration of Competing Interest None to declare., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

The emergence of SARS-CoV-2 variants of concern (VoCs) has exacerbated the COVID-19 pandemic. Currently available monoclonal antibodies and vaccines appear to have reduced efficacy against some of these VoCs. Antivirals targeting conserved proteins of SARS-CoV-2 are unlikely to be affected by mutations arising in VoCs and should therefore be effective against emerging variants. We here investigate the efficacy of molnupiravir, currently in phase 2 clinical trials, in hamsters infected with Wuhan strain or B.1.1.7 and B.1.351 variants. Molnupiravir proved to be effective against infections with each of the variants and therefore may have potential combating current and future emerging VoCs., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Sarcoidosis is a systemic granulomatous disease that in most patients affects the lung. Pulmonary fibrotic sarcoidosis is clinically, radiologically, and pathologically a heterogeneous condition. Although substantial indirect evidence suggests small airways involvement, direct evidence currently is lacking., Research Question: What is the role of the (small) airways in fibrotic sarcoidosis?, Study Design and Methods: Airway morphologic features were investigated in seven explant lungs with end-stage fibrotic sarcoidosis using a combination of CT scanning (large airways), micro-CT scanning (small airways), and histologic examination and compared with seven unused donor lungs as controls with specific attention focused on different radiologically defined sarcoidosis subtypes., Results: Patients with central bronchial distortion (n = 3), diffuse bronchiectasis (n = 3), and usual interstitial pneumonia pattern (n = 1) were identified based on CT scan, showing a decrease and narrowing of large airways, a similar airway number and increased airway diameter of more distal airways, or an increase in airway number and airway diameter, respectively, compared with control participants. The number of terminal bronchioles per milliliter and the total number of terminal bronchioles were decreased in all forms of fibrotic sarcoidosis. Interestingly, the number of terminal bronchioles was inversely correlated with the degree of fibrosis. Furthermore, we identified granulomatous remodeling as a cause of small airways loss using serial micro-CT scanning and histologic examination., Interpretation: The large airways are involved differentially in subtypes of sarcoidosis, but the terminal bronchioles universally are lost. This suggests that small airways loss forms an important aspect in the pathophysiologic features of fibrotic pulmonary sarcoidosis., (Copyright © 2021 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

Background and Study Aims: The international consensus Fukuoka guideline (Fukuoka ICG), The European evidence-based guideline on pancreatic cystic neoplasms (European EBG) and the American Gastroenterological Association institute guideline on the diagnosis and management of asymptomatic neoplastic pancreatic cysts (AGA IG) are 3 frequently cited guidelines for the risk stratification of neoplastic pancreatic cysts. The aim of this study was to assess the accuracy of detecting malignant cysts by strictly applying these guidelines retrospectively to a cohort of surgically resected pancreatic cysts., Patients and Methods: 72 resected cysts were included in the analysis. Invasive carcinoma, high grade dysplasia and neuro-endocrine tumour were considered as "malignant cysts" for the purpose of the study., Results: 32% of the resected cysts were malignant. The analysis showed that the Fukuoka ICG, European EBG and AGA IG had a sensitivity of 66,8%, 95,5%, 80%; a specificity of 26,8%, 11,3%, 43,8%; a positive predictive value of 31,8%, 35%, 47,1% and a negative predicted value of 61,1%, 83,3%, 77,8% respectively. The missed malignancy rate was respectively 11,3%, 1,5%, 7,7% and surgical overtreatment was respectively 48,4%, 59,1%, 34,6%., Conclusion: In this retrospective analysis, the European EBG had the lowest rate of missed malignancy at the expense of a high number of "unnecessary" resections. The Fukuoka ICG had the highest number of missed malignancy. The AGA IG showed the lowest rate of unnecessary surgery at the cost of a high number of missed malignancy. There is need to develop better biomarkers to predict the risk of malignancy., Competing Interests: The authors declare that they have no conflict of interest, (© Acta Gastro-Enterologica Belgica.)

Background: Within one year after its emergence, more than 108 million people acquired SARS-CoV-2 and almost 2·4 million succumbed to COVID-19. New SARS-CoV-2 variants of concern (VoC) are emerging all over the world, with the threat of being more readily transmitted, being more virulent, or escaping naturally acquired and vaccine-induced immunity. At least three major prototypic VoC have been identified, i.e. the United Kingdom, UK (B.1.1.7), South African (B.1.351) and Brazilian (B.1.1.28.1) variants. These are replacing formerly dominant strains and sparking new COVID-19 epidemics., Methods: We studied the effect of infection with prototypic VoC from both B.1.1.7 and B.1.351 variants in female Syrian golden hamsters to assess their relative infectivity and virulence in direct comparison to two basal SARS-CoV-2 strains isolated in early 2020., Findings: A very efficient infection of the lower respiratory tract of hamsters by these VoC is observed. In line with clinical evidence from patients infected with these VoC, no major differences in disease outcome were observed as compared to the original strains as was quantified by (i) histological scoring, (ii) micro-computed tomography, and (iii) analysis of the expression profiles of selected antiviral and pro-inflammatory cytokine genes. Noteworthy however, in hamsters infected with VoC B.1.1.7, a particularly strong elevation of proinflammatory cytokines was detected., Interpretation: We established relevant preclinical infection models that will be pivotal to assess the efficacy of current and future vaccine(s) (candidates) as well as therapeutics (small molecules and antibodies) against two important SARS-CoV-2 VoC., Funding: Stated in the acknowledgment., Competing Interests: Declaration of Competing Interest Authors declare no conflict of interests., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Diffuse malignant mesothelioma (MM) is an incurable tumour of the serosal membranes, which is often caused by exposure to asbestos and commonly diagnosed at advanced stage. Malignant mesothelioma in situ (MMIS) is now included as diagnostic category by the World Health Organization (WHO). However, our international survey of 34 pulmonary pathologists with an interest in MM diagnosis highlights inconsistency regarding how the diagnosis is being made by experts, despite published guidelines. Whilst the WHO restricts the diagnosis to surgical samples, the very concept has implication for cytological diagnosis, which is already regarded as controversial in itself by some. MMIS is currently only applicable as precursor to MM with an epithelioid component, and raises the possibility for different molecular pathways for different histological MM subtypes. The clinical implications of MMIS at this stage are uncertain, but aggressive therapies are being initiated in some instances. Based on the results of the survey we here present a critical appraisal of the concept, its clinical and conceptual implications and provide practice suggestions for diagnosis. A low threshold for ancillary testing is suggested. The designations of 'malignant mesothelioma, cannot exclude MMIS' or 'atypical mesothelial proliferation with molecular indicators of malignancy, so-called MMIS' could be used on cytology samples, adding 'no evidence of invasion in sample provided' for surgical samples. Clinical and radiological correlation are integral to diagnosis and best done at multidisciplinary meetings. Finally, collaborative studies are required to improve our understanding of MMIS., (Copyright © 2021. Published by Elsevier B.V.)

Background: Connective tissue growth factor (CTGF) is an important mediator in several fibrotic diseases, including lung fibrosis. We investigated CTGF-expression in chronic lung allograft dysfunction (CLAD) and pulmonary graft-versus-host disease (GVHD)., Materials and Methods: CTGF expression was assessed by quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry in end-stage CLAD explant lung tissue (bronchiolitis obliterans syndrome (BOS), n=20; restrictive allograft syndrome (RAS), n=20), pulmonary GHVD (n=9). Unused donor lungs served as control group (n=20). Next, 60 matched lung transplant recipients (BOS, n=20; RAS, n=20; stable lung transplant recipients, n=20) were included for analysis of CTGF protein levels in plasma and broncho-alveolar lavage (BAL) fluid at 3 months post-transplant, 1 year post-transplant, at CLAD diagnosis or 2 years post-transplant in stable patients., Results: qPCR revealed an overall significant difference in the relative content of CTGF mRNA in BOS, RAS and pulmonary GVHD vs. controls (p=0.014). Immunohistochemistry showed a significant higher percentage and intensity of CTGF-positive respiratory epithelial cells in BOS, RAS and pulmonary GVHD patients vs. controls (p<0.0001). BAL CTGF protein levels were significantly higher at 3 months post-transplant in future RAS vs. stable or BOS (p=0.028). At CLAD diagnosis, BAL protein content was significantly increased in RAS patients vs. stable (p=0.0007) and BOS patients (p=0.042). CTGF plasma values were similar in BOS, RAS, and stable patients (p=0.74)., Conclusions: Lung CTGF-expression is increased in end-stage CLAD and pulmonary GVHD; and higher CTGF-levels are present in BAL of RAS patients at CLAD diagnosis. Our results suggest a potential role for CTGF in CLAD, especially RAS, and pulmonary GVHD., Competing Interests: RG has received research support from Fibrogen Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Vanstapel, Goldschmeding, Broekhuizen, Nguyen, Sacreas, Kaes, Heigl, Verleden, De Zutter, Verleden, Weynand, Verbeken, Ceulemans, Van Raemdonck, Neyrinck, Schoemans, Vanaudenaerde and Vos.)

Background: The antifungal drug itraconazole exerts in vitro activity against SARS-CoV-2 in Vero and human Caco-2 cells. Preclinical and clinical studies are required to investigate if itraconazole is effective for the treatment and/or prevention of COVID-19., Methods: Due to the initial absence of preclinical models, the effect of itraconazole was explored in a clinical, proof-of-concept, open-label, single-center study, in which hospitalized COVID-19 patients were randomly assigned to standard of care with or without itraconazole. Primary outcome was the cumulative score of the clinical status until day 15 based on the 7-point ordinal scale of the World Health Organization. In parallel, itraconazole was evaluated in a newly established hamster model of acute SARS-CoV-2 infection and transmission, as soon as the model was validated., Findings: In the hamster acute infection model, itraconazole did not reduce viral load in lungs, stools or ileum, despite adequate plasma and lung drug concentrations. In the transmission model, itraconazole failed to prevent viral transmission. The clinical trial was prematurely discontinued after evaluation of the preclinical studies and because an interim analysis showed no signal for a more favorable outcome with itraconazole: mean cumulative score of the clinical status 49 vs 47, ratio of geometric means 1.01 (95% CI 0.85 to 1.19) for itraconazole vs standard of care., Interpretation: Despite in vitro activity, itraconazole was not effective in a preclinical COVID-19 hamster model. This prompted the premature termination of the proof-of-concept clinical study., Funding: KU Leuven, Research Foundation - Flanders (FWO), Horizon 2020, Bill and Melinda Gates Foundation., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: Sertraline is a selective serotonin reuptake inhibitor which is often used as first-line treatment for depression. Several patterns of interstitial lung disease attributable to sertraline have been reported in the literature., Case Report: A 69-year-old patient, who had been taking sertraline to treat severe depression for 10 months, presented with a deterioration in his general condition and respiratory symptoms found to be associated with bilateral pneumonitis. An exhaustive assessment did not reveal any infectious or autoimmune aetiology. Transthoracic lung biopsy revealed a pattern of eosinophilic lung disease. Sertraline-induced lung toxicity was then suspected and this treatment was therefore stopped. The patient's symptoms resolved and the chest imaging normalized., Conclusions: Our observation suggests that sertraline was the cause of chronic eosinophilic pneumonia characterized by an insidious clinical presentation several months after starting the medication. Given its widespread prescription, we encourage any clinician facing this disease to pay attention to possible drug-induced origins of lung disease., (Copyright © 2020 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: Congenital pulmonary airway malformation (CPAM), previously described as congenital cystic adenomatoid malformation (CCAM), is a congenital disorder of lung parenchyma. The association with the presence of a malignant transformation like rhabdomyosarcoma, pleuropulmonary blastoma, and most common invasive mucinous adenocarcinoma (IMA) is a rare development described in patients with CPAM., Patients and Methods: Here, we report the case of a 68-year-old male patient who underwent a right lower lobectomy for a mass in the right pulmonary lobe. From his clinical history, we noted a recurrent pulmonary infection of a bullous malformation in the right lower lobe treated with antibiotics., Results: The histopathological finding showed an invasive mucinous adenocarcinoma arising in a type 1 CPAM in the right lower lobe. A review of presentation, diagnosis, and treatment of this association is described in a case report., Conclusions: Surgical resection should be considered in adults with asymptomatic cysts to prevent malignant transformation. For further analysis, histopathological examination of specimen is essential for a proper diagnosis and eventually further postoperative treatment.

A Belgian ring trial for pan-TRK immunohistochemistry (IHC) staining was organised to harmonise pan-TRK IHC staining protocols and interpretation. As a reference method, the VENTANA pan-TRK Assay (clone EPR17341) on the Benchmark Ultra platform was selected. Six samples were selected: 2 negative, 2 fusion positive and 2 samples with wild-type endogenous TRK expression. Each participating laboratory stained the slides using their routine pan-TRK IHC and reported their results. In addition, they were asked to return one TRK-stained slide from each case. The coordinating lab evaluated these slides, compared them with the reference method and scored them. Two clones were used during the ring trial: A7H6R (Cell Signaling) and EPR17341 (Abcam/Ventana). Seven protocols achieved a sufficient performance mark, and three labs were advised to further optimise the protocol. Interpretation of pan-TRK IHC proved to be challenging in cases with physiological TRK expression. In addition, depending on the NTRK fusion partner, the staining can vary strongly in both intensity and staining pattern. Labs using the Ventana ready-to-use system based on the EPR17341 clone and using the recommended protocol settings scored best. However, given some small optimisation, all labs scored well on the technical staining and the succeeding evaluation.