Triaging patients in the outbreak of the 2019 novel coronavirus

In the end of 2019, the epidemic of a new coronavirus (SARS-CoV-2) occurred in Wuhan and spread rapidly. Changsha, a city located south to the epicenter, was soon impacted. To control the transmission of the coronavirus and avoid nosocomial infection, triage procedures based on epidemiology were implemented in a local hospital of the city. This retrospective study analyzed the data collected during the triage period and found that COVID-19 patients were enriched seven folds into the Section A designated for rapid detection and quarantine. On the other side, roughly triple amounts of visits were received at the Section B for patients without obvious epidemiological history. Eight COVID-19 cases were spotted out of 247 suspected patients. More than 50% of the suspected patients were submitted to multiple rounds of nucleic acid analysis for SARS-CoV-2 infection. Of the 239 patients who were diagnosed as negative of the virus infection,188 were successfully revisited and none was reported as a COVID-19 case. Of the eight COVID-19 patients, three were confirmed only after multiple rounds of nucleic acid analysis. Besides comorbidities, delayed sharing of epidemiological history added another layer of complexity to the diagnosis in practice. While SARS-CoV-2 epidemic is being alerted in many countries, our report will be helpful to other colleagues in rapid identification of COVID-19 cases and controlling the transmission of the disease.

hCD47 induces immune tolerance of human macrophages to porcine endothelial cells / 器官移植

Objective To investigate the effect of human CD47 (hCD47) in inducing the immune tolerance of human macrophages to porcine endothelial cells. Methods The porcine iliac endothelial cell (PIEC) transfected with pCDH-hCD47-FLAG plasmid was assigned into the pCDH-hCD47 group, PIEC transfected with pCDH-FLAG empty vector plasmid was assigned into the pCDH group, PIEC transfected with hCD47-dN was assigned into the pCDH-hCD47-dN group and human umbilical vein endothelial cell (HUVEC) was assigned into the positive control group. The cells were co-cultured with human macrophages to detect and analyze the phosphorylation of signal regulatory protein α (SIRPα) and the killing effect of human macrophages on PIEC. Furthermore, porcine arteriae endothelial cell (PAEC) was isolated from GT－/－ and GT－/－/ hCD 47 gene editing pigs to analyze the phosphorylation of SIRPα and the killing effect of human macrophages on PAEC. Results The pCDH group cells could not induce the phosphorylation of SIRPα, whereas the pCDH-hCD47 group cells could activate the phosphorylation of SIRPα after 10 min co-culture with human macrophages, and the degree of phosphorylation of SIRPα was increased with the prolongation of the co-culture time. The pCDH-hCD47-dN group cells failed to activate the phosphorylation of SIRPα. Human macrophages exerted significant effect on killing the pCDH group cells. The pCDH-hCD47 group cells could evidently inhibit the killing effect of human macrophages (P < 0.05), whereas the pCDH-hCD47-dN cells failed to suppress the killing effect of human macrophages. GT－/－-PAEC could not activate the phosphorylation of SIRPα after co-culture with human macrophages. However, GT－/－/hCD47-PAEC significantly activated the phosphorylation of SIRPα after co-culture with human macrophages. Human macrophages exerted significant killing effect on GT－/－-PAEC, and GT－/－/hCD47-PAEC could obviously inhibit the killing effect of human macrophages (P < 0.05). Conclusions The expression of hCD47 in the porcine endothelial cells can inhibit the killing effect of human macrophages on endothelial cells by activating the phosphorylation of SIRPα.