Insights into the lung microenvironment after severe COVID-19

The SARS-CoV-2 is the betacoronavirus responsible for the coronavirus disease 2019 (COVID-19) pandemic. Severe COVID-19 affects approximately 10-15% of patients and results in prolonged morbidity and mortality. Little is known about the immunophenotypic changes of the lung parenchyma driven by the viral infection in patients who die of severe COVID-19. Ultrasound-guided lung biopsies (LB) were collected (IRB approval#1561/21) within few hours from death in 15 severe COVID-19 patients between November 2020 and January 2021, in two patients who underwent lung transplantation after COVID-19 and in one patient who had surgery for bacterial superinfection during COVID-19 disease. All samples underwent histologic and immunohistochemistry evaluation and molecular profiling using the nCounter Host Response and Coronavirus Panel plus. As controls, lungs from end-stage usual interstitial pneumonia (UIP;n=9) and from lobectomy for lung cancer (Norm;n=5) were used. Eleven lungs (61%) were positive for SARS-CoV-2 RNA. Signs of diffuse alveolar damage (DAD) were observed in 6 patients (30%). COVID-19 lungs showed a marked macrophage infiltration with M2 polarization compared with controls. Globally, COVID-19 lungs showed distinct molecular profiles from UIP or Norm lungs. Specifically, a marked upregulation of interferon-genes that was directly correlated with SARS-CoV-2 genes was seen in COVID-19 lungs. COVID-19-specific genes signatures (Log2FC >1.5;adj p<0.05) obtained using VENN diagram showed impairment of the STAT3-pathway accompanied by the upregulation of the NFkB signaling. Results herein provide new insights into lung alterations induced by severe COVID-19 and suggest novel potential targets for therapeutic intervention.

SARS-CoV-2 infection in cystic fibrosis during the first pandemic wave in Italy: a multi-centre prospective study with a control group

Background: Patients with cystic fibrosis (CF) are at high risk of developing severe forms of viral respiratory infections. This study aimed at comparing symptoms and clinical course of SARS-CoV2 infection with other respiratory infections in patients with CF. Methods: We carried out a prospective multicentre cohort study within the Italian CF Society involving 32 CF centres following 6,597 patients. CF centres were contacted to collect baseline and follow-up data of all patients who had reported symptoms suggestive of COVID-19 or who had had contact with a positive/suspected case between the end of February and July 2020. Symptoms and clinical course of the infection were compared between patients who tested positive by molecular testing (cases) and those who tested negative (controls). Results: Thirty patients were reported from the centres, 16 of whom tested positive and 14 negative. Fever, cough, asthenia and dyspnea were the most frequently reported symptoms and their frequency were not significant different between groups. Eight cases (50%) were hospitalised but none required ICU admission. Two adults with a history of lung transplant required non-invasive ventilation;none required ICU admission. All patients fully recovered without short-term sequelae. Changes in FEV1 (percent of predicted) after recovery were not significantly different between groups (median, interquartile range: 3.0%, –1.5, 5.5 among cases and –3.0%, –8.5, 6.3 among controls, P = 0.48). Conclusions: Symptoms and clinical course of SARS-CoV-2 infection in our patients was not significantly different from other respiratory infections. The clinical course of COVID-19 was relatively favourable, however CF patients with severely impaired respiratory function and organ transplant may develop complications and a negative outcome. The study is ongoing, and we are recruiting patients during the second wave of the pandemic.

Lung Allograft Dysfunction in a COVID-19 Transplanted Patient is Associated with a Peculiar Immunopathological Phenotype

Purpose Lung transplantation (LT) after severe SARS-CoV-2 infection is emerging as a life-saving medical procedure for selected patients who experience acute respiratory distress syndrome (ARDS). We present the first immunopathological evaluation of a lung allograft rejection in a patient who underwent LT because of irreversible ARDS related to COVID-19. Methods Two male patients with irreversible ARDS caused by COVID-19 underwent bilateral LT at our Institution. A surveillance transbronchial biopsy (TBB) was performed 2 months after LT in the first patient (Pt#1), while the second patient (Pt#2) died because of allograft rejection at day 62 post LT and explanted lungs were retrieved. CT imaging of the lungs was performed three days before death. Morphological examination was performed by H&E, whereas the immunophenotyping was performed by immunohistochemistry. Results Imaging and morphological examination of Pt#2 lungs indicated the presence of a graft dysfunction with features of a restrictive, widespread usual interstitial pneumonia-like syndrome (Fig. 1A, B). The immunophenotyping showed that B-lymphocytes (CD20-positive) were nearly absent, CD8-T-cells were not particularly expanded (mean positive cells within the lung stroma=13.8%;Fig. 1C), and the CD4/CD8 ratio was not decreased (Fig. 1D). The T-regs (Foxp3-positive) were 6% of the overall population (Fig. 1E). Analysis of the immune checkpoint molecules PD1, Tigit, CTLA4 and PDL1 showed that the expression of PD-L1 alone was highly increased in vases and in alveolar cells of rejected lungs, whereas it was nearly undetectable in the TBB from Pt#1 (Fig. 1F, G). Conclusion PDL1 expression in vases was previously documented as a sign of indirect ARDS. Together with our preliminary data, we can hypothesize that PDL1 may play a role in tissue effacement and graft failure, possibly indicating poor allograft prognosis.