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The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently the most pressing medical and socioeconomic challenge. Constituting important correlates of protection, the determination of virus-neutralizing antibodies (NAbs) is indispensable for convalescent plasma selection, vaccine candidate evaluation, and immunity certificates. In contrast to standard serological ELISAs, plaque reduction neutralization tests (PRNTs) are laborious, time-consuming, expensive, and restricted to specialized laboratories. To replace microscopic counting-based SARS-CoV-2 PRNTs by a novel assay exempt from genetically modified viruses, which are inapplicable in most diagnostics departments, we established a simple, rapid, and automated SARS-CoV-2 neutralization assay employing an in-cell ELISA (icELISA) approach. After optimization of various parameters such as virus-specific antibodies, cell lines, virus doses, and duration of infection, SARS-CoV-2-infected cells became amenable as direct antigen source for quantitative icELISA. Antiviral agents such as human sera containing NAbs or antiviral interferons dose dependently reduced the SARS-CoV-2-specific signal. Applying increased infectious doses, the icELISA-based neutralization test (icNT) was superior to PRNT in discriminating convalescent sera with high from those with intermediate neutralizing capacities. In addition, the icNT was found to be specific, discriminating between SARS-CoV-2-specific NAbs and those raised against other coronaviruses. Altogether, the SARS-CoV-2 icELISA test allows rapid (<48 h in total, read-out in seconds) and automated quantification of virus infection in cell culture to evaluate the efficacy of NAbs and antiviral drugs using reagents and equipment present in most routine diagnostics departments.

Background: Iatrogenic tracheobronchial injury is a rare, but severe complication of endotracheal intubation. Risk factors are emergency intubation, percutaneous dilatational tracheostomy and intubation with double lumen tube. Regarding these procedures, underlying patients often suffer from severe comorbidities. The aim of this study was to evaluate the results of a standardized treatment algorithm in a referral center with focus on the surgical approach. Methods: Sixty-four patients with iatrogenic tracheal lesion were treated in our department by standardized management adopted to clinical findings between 2003 and 2019. Patients with superficial laceration were treated conservatively. In the case of transmural injury of the tracheal wall and necessity of mechanical ventilation, patients underwent surgery. We decided on a cervical surgical approach for lesions limited to the trachea. In case of involvement of a main bronchus we performed thoracotomy. Data were evaluated retrospectively. Results: In 19 patients the tracheal lesion occurred in elective intubation and in 17 patients during emergency intubation. In 23 cases a tracheal tear occurred during percutaneous dilatational tracheostomy and in three patients at replacement of a tracheostomy tube. Two patients received laceration during bronchoscopy. Twenty-nine patients underwent surgery with cervical approach and 14 underwent thoracotomy. There was no difference in the mortality of these groups. Treatment of tracheal tear was successful in 62 individuals. Nine patients died of multi organ dysfunction syndrome (MODS), two of them during surgery. Conclusions: Iatrogenic tracheal laceration is a life-threatening complication and the mortality after tracheal injury is high, even in a specialized thoracic unit. Conservative management in patients with superficial tracheal lesion is a feasible procedure. In case of complete laceration of tracheal wall, surgical therapy is recommendable, whereby several approaches of surgical management seem to be equivalent.

Our data indicate that the detection of BKV and TTV is not a risk factor for renal impairment after LT. A correlation of TTV and BKV viral load seems to be an indicator for the immune status of the host.