Lung mesenchymal cells from patients with COVID-19 driven lung fibrosis: Several features with CTD-ILD derived cells but with higher response to fibrogenic signals and might be more pro-inflammatory.

A subset of severe COVID19 patients develop pulmonary fibrosis, but the pathophysiology of this complication is still unclear. We previously described the possibility to isolate lung mesenchymal cells (LMC) by culturing broncho-alveolar lavage (BAL) cells from patients with pulmonary fibrosis or chronic lung allograft dysfunction. Aim of this study was to investigate the possibility to isolate and characterize LMC from BAL of patients that, two months after discharge for severe COVID19, show CT signs of post-COVID19 fibrosis (Post-COVID) and in some cases has been considered transplant indication. Results were compared with those from BAL of patients with collagen tissue disease-associated interstitial fibrosis (CTD-ILD). BAL fluid levels of TGFß, VEGF, TIMP2, RANTES, IL6, IL8, and PAI1 were assessed. LMC were cultured and expanded, phenotyped by flow cytometry, and tested for osteogenic and adipogenic differentiation. Finally, we tested immunomodulatory and proliferative capabilities, collagen I production + /- TGF-beta stimulation. BAL cytokine and growth factor levels were comparable in the two groups. Efficiency of isolation from BAL was 100% in post-COVID compared to 63% in CTD-ILD. LMC from post-COVID were positive for CD105, CD73, CD90, and negative for CD45, CD34, CD19 and HLA-DR as in CTD-ILD samples. Post-COVID LMC displayed higher collagen production with respect to CTD-ILD LMC. Immunomodulatory capacity towards lymphocytes was very low, while Post-COVID LMC significantly upregulated pro-inflammatory cytokine production by healthy PBMCs. Our preliminary data suggest that LMC from post-COVID19 fibrosis patients share several features with CTD-ILD ones but might have a higher response to fibrogenic signals and pro-inflammatory profile.

Post-acute coronavirus disease 2019 (COVID 19) syndrome: HLH and cholangiopathy in a lung transplant recipient.

Background: Sars-CoV2 can cause severe pneumonia and acute respiratory distress syndrome (ARDS). In COVID-19-associated respiratory failure, lung transplantation might be an option (Bharat A). Case report: A previously healthy 63-year-old man with a nasopharyngeal swab positive for SarsCoV2 and radiological evidence of interstitial lung consolidations developed acute respiratory distress that required intubation and veno-venous extracorporeal membrane oxygenation support (VV ECMO). Because of no recovery of his lung function, he underwent a bilateral lung transplant. ICU stay was complicated by several episodes of bacterial superinfections and an increase of liver function tests (LFTs). Afterward, he faced a progressive clinical worsening associated to severe anemia, further rise of indices of cholestasis, hypertriglyceridemia and hyperferritinemia. Bone marrow smear showed a picture compatible with haemophagocytic lymphohistocytosis (HLH) and first and second line therapy were started. In addition, a transjugular hepatic biopsy was performed with histopathological evidence of portal and periportal fibrosis, compatible with Covid 19-related cholangiopathy. During the hospital stay, he developed several MDR opportunistic infections. The patient died few months later from multiorgan failure secondary to septic shock. A post-mortem confirmed a diagnosis of cholangiopathy, and medullary erythro-haemophagocytosis. Conclusion: Post Covid19 syndrome is a clinical entity that includes novel and old sequelae following recovery from Sars-CoV2 infections. Early identification of these diseases is crucial for adequate management and might influence the long term prognosis of these patients.

Neuropathological findings from COVID-19 patients with neurological symptoms argue against a direct brain invasion of SARS-CoV-2: A critical systematic review.

BACKGROUND AND PURPOSE: Neuropathological studies can elucidate the mechanisms of nervous system damage associated with SARS-CoV-2 infection. Despite literature on this topic is rapidly expanding, correlations between neurological symptoms and brain pathology findings in COVID-19 patients remain largely unknown. METHODS: We performed a systematic literature review on neuropathological studies in COVID-19, including 438 patients from 45 articles published by April 22, 2021. We retrieved quantitative data regarding demographic, clinical, and neuropathological findings. We carried out a Wilcoxon rank sum test or χ2 test to compare patients' subgroups based on different clinical and brain pathology features. RESULTS: Neuropathological findings in COVID-19 patients were microgliosis (52.5%), astrogliosis (45.6%), inflammatory infiltrates (44.0%), hypoxic-ischemic lesions (40.8%), edema (25.3%), and hemorrhagic lesions (20.5%). SARS-CoV-2 RNA and proteins were identified in brain specimens of 41.9% and 28.3% of subjects, respectively. Detailed clinical information was available from 245 patients (55.9%), and among them, 96 subjects (39.2%) had presented with neurological symptoms in association with typical COVID-19 manifestations. We found that: (i) the detection rate of SARS-CoV-2 RNA and proteins in brain specimens did not differ between patients with versus those without neurological symptoms; (ii) brain edema, hypoxic-ischemic lesions, and inflammatory infiltrates were more frequent in subjects with neurological impairment; (iii) neurological symptoms were more common among older individuals. CONCLUSIONS: Our systematic revision of clinical correlates in COVID-19 highlights the pathogenic relevance of brain inflammatory reaction and hypoxic-ischemic damage rather than neuronal viral load. This analysis indicates that a more focused study design is needed, especially in the perspective of potential therapeutic trials.

Depletion of circulating IgM memory B cells predicts unfavourable outcome in COVID-19.

Impaired immune responses have been hypothesised to be a possible trigger of unfavourable outcomes in coronavirus disease 2019 (COVID-19). We aimed to characterise IgM memory B cells in patients with COVID-19 admitted to an internal medicine ward in Northern Italy. Overall, 66 COVID-19 patients (mean age 74 ± 16.6 years; 29 females) were enrolled. Three patients (4.5%; 1 female) had been splenectomised and were excluded from further analyses. Fifty-five patients (87.3%) had IgM memory B cell depletion, and 18 (28.6%) died during hospitalisation (cumulative incidence rate 9.26/100 person-week; 5.8-14.7 95% CI). All patients who died had IgM memory B cell depletion. A superimposed infection was found in 6 patients (9.5%), all of them having IgM memory B cell depletion (cumulative incidence rate 3.08/100 person-week; 1.3-6.8 95% CI). At bivariable analyses, older age, sex, number of comorbidities, and peripheral blood lymphocyte count < 1500/µl were not correlated with IgM memory B cell depletion. A discrete-to-marked reduction of the B-cell compartment was also noticed in autoptic spleen specimens of two COVID-19 patients. We conclude that IgM memory B cells are commonly depleted in COVID-19 patients and this correlates with increased mortality and superimposed infections.

Fibrotic progression and radiologic correlation in matched lung samples from COVID-19 post-mortems.

Data on the pathology of COVID-19 are scarce; available studies show diffuse alveolar damage; however, there is scarce information on the chronologic evolution of COVID-19 lung lesions. The primary aim of the study is to describe the chronology of lung pathologic changes in COVID-19 by using a post-mortem transbronchial lung cryobiopsy approach. Our secondary aim is to correlate the histologic findings with computed tomography patterns. SARS-CoV-2-positive patients, who died while intubated and mechanically ventilated, were enrolled. The procedure was performed 30 min after death, and all lung lobes sampled. Histopathologic analysis was performed on thirty-nine adequate samples from eight patients: two patients (illness duration < 14 days) showed early/exudative phase diffuse alveolar damage, while the remaining 6 patients (median illness duration-32 days) showed progressive histologic patterns (3 with mid/proliferative phase; 3 with late/fibrotic phase diffuse alveolar damage, one of which with honeycombing). Immunohistochemistry for SARS-CoV-2 nucleocapsid protein was positive predominantly in early-phase lesions. Histologic patterns and tomography categories were correlated: early/exudative phase was associated with ground-glass opacity, mid/proliferative lesions with crazy paving, while late/fibrous phase correlated with the consolidation pattern, more frequently seen in the lower/middle lobes. This study uses an innovative cryobiopsy approach for the post-mortem sampling of lung tissues from COVID-19 patients demonstrating the progression of fibrosis in time and correlation with computed tomography features. These findings may prove to be useful in the correct staging of disease, and this could have implications for treatment and patient follow-up.