Feasibility and impact on diagnosis of peripheral pulmonary lesions under real-time direct vision by Iriscope®.

Introduction Interventional pneumology plays a crucial role in the diagnosis of peripheral pulmonary lesions (PPLs), offering a minimally invasive approach with a low risk of complications. Iriscope® is a novel device that provides a direct and real-time image of PPLs. The objective of this study is to demonstrate the feasibility and impact of Iriscope® in diagnosing PPLs by analyzing its ability to directly visualize lesions and support accurate sampling during radial endobronchial ultrasound (rEBUS) and electromagnetic navigation bronchoscopy (ENB) combined with rEBUS. Methods A single-center prospective study was conducted from December 2022 to October 2023 on patients with suspicious PPLs. The diagnostic approach involved either rEBUS alone or in combination with ENB. In all cases, an additional novel technique called Iriscope® (Lys Medical, Charleroi, Belgium) was also applied. Iriscope® findings of each lesion were evaluated individually by three expert interventional pulmonologists. Results Seventy PPLs suspected of malignancy were included in the study. The PPLs underwent examination by ENB combined with rEBUS (55) or by rEBUS alone (15). Diagnosis was obtained in 68.6% (48/70) of cases. Iriscope® provided a direct, real-time view of 57.1% (40/70) of PPLs with a positive predictive value of 92.5% (37/40). This technique was able to visualize 72% (39/54) of malignant lesions, while only 6.1% (1/16) of benign lesions showed pathologic changes. The most common findings observed with Iriscope® were: Mucosal thickening and infiltration (92,5%), increased capillary vascularization (82%), pale or grayish mucosa (72,5%), obstruction with accumulation of secretions (50%) and cobblestone mucosa (15%). Conclusion Iriscope® is a promising technique in the diagnostic process of PPLs, providing real-time pathologic imaging that facilitates accurate sampling. Further studies are needed to evaluate success rate of Iriscope-mediated repositioning and to establish predictive patterns for malignant or even benign diseases.

Neutrophil Extracellular Traps, Local IL-8 Expression, and Cytotoxic T-Lymphocyte Response in the Lungs of Patients With Fatal COVID-19.

BACKGROUND: Excessive inflammation is pathogenic in the pneumonitis associated with severe COVID-19. Neutrophils are among the most abundantly present leukocytes in the inflammatory infiltrates and may form neutrophil extracellular traps (NETs) under the local influence of cytokines. NETs constitute a defense mechanism against bacteria, but have also been shown to mediate tissue damage in a number of diseases. RESEARCH QUESTION: Could NETs and their tissue-damaging properties inherent to neutrophil-associated functions play a role in the respiratory failure seen in patients with severe COVID-19, and how does this relate to the SARS-CoV-2 viral loads, IL-8 (CXCL8) chemokine expression, and cytotoxic T-lymphocyte infiltrates? STUDY DESIGN AND METHODS: Sixteen lung biopsy samples obtained immediately after death were analyzed methodically as exploratory and validation cohorts. NETs were analyzed quantitatively by multiplexed immunofluorescence and were correlated with local levels of IL-8 messenger RNA (mRNA) and the density of CD8+ T-cell infiltration. SARS-CoV-2 presence in tissue was quantified by reverse-transcriptase polymerase chain reaction and immunohistochemistry analysis. RESULTS: NETs were found in the lung interstitium and surrounding the bronchiolar epithelium with interindividual and spatial heterogeneity. NET density did not correlate with SARS-CoV-2 tissue viral load. NETs were associated with local IL-8 mRNA levels. NETs were also detected in pulmonary thrombi and in only one of eight liver tissues. NET focal presence correlated negatively with CD8+ T-cell infiltration in the lungs. INTERPRETATION: Abundant neutrophils undergoing NETosis are found in the lungs of patients with fatal COVID-19, but no correlation was found with viral loads. The strong association between NETs and IL-8 points to this chemokine as a potentially causative factor. The function of cytotoxic T-lymphocytes in the immune responses against SARS-CoV-2 may be interfered with by the presence of NETs.

Histopathological findings in fatal COVID-19 severe acute respiratory syndrome: preliminary experience from a series of 10 Spanish patients.

In December 2019, an outbreak of severe acute respiratory syndrome associated to SARS-CoV2 was reported in Wuhan, China. To date, little is known on histopathological findings in patients infected with the new SARS-CoV2. Lung histopathology shows features of acute and organising diffuse alveolar damage. Subtle cellular inflammatory infiltrate has been found in line with the cytokine storm theory. Medium-size vessel thrombi were frequent, but capillary thrombi were not present. Despite the elevation of biochemical markers of cardiac injury, little histopathological damage could be confirmed. Viral RNA from paraffin sections was detected at least in one organ in 90% patients.