Rapid Screening Diagnosis of SARS-COV-2 Infection With IgM-igG Combined Antibody Test Using Peripheral Blood (preprint)

Background Rapid and convenient screening for identification of SARS-CoV-2 infected individuals are key to prevent and control this pandemic.Methods The peripheral blood samples were collected from coronavirus disease 2019 (COVID-19) patients and asymptomatic carriers to evaluate the test characteristics of the IgM-IgG combined assay for SARS-CoV-2 compared to that of serum samples and enzyme-linked immuno sorbent assay (ELISA). Close contacts, healthcare workers and workforces were recruited and screened using this assay.Results The sensitivity of the rapid IgM-IgG combined antibody test for SARS-CoV-2 using peripheral blood (sued as a POCT) was 97.0% and the specificity was 99.2%, which was consistent with the result obtained using serum sample (consistency is about 100%). Furthermore, this POCT assay also can detect IgM and IgG antibodies of SARS-CoV‐2 in asymptomatic carriers, with 19 of the 20 RT-PCR confirmed asymptomatic carriers testing positive. Therefore, this POCT assay was used for population screening of SARS-CoV-2 infection diagnosis. First, it found 4 positive close contacts among the 10 cases, and there were three IgM positive cases and one IgG positive case among them. It is worth noting that the IgM positive cases also tested positive for the nucleic acid of the SARS-CoV-2. Second, there was one IgM positive assay among the 63 healthcare workers, but RT-PCR of SARS CoV-2 was negative. Third, for workforces screening, there were no positive cases.Conclusions The IgM-IgG combined antibody test of SARS-CoV-2 can be used as a POCT for rapid screening of SARS-CoV-2 infection.

Longitudinal peripheral blood transcriptional analysis of COVID-19 patients captures disease progression and reveals potential biomarkers (preprint)

COVID-19, caused by SARS-CoV-2, is an acute self-resolving disease in most of the patients, but some patients can develop a severe illness or even death. To characterize the host responses and identify potential biomarkers during disease progression, we performed a longitudinal transcriptome analysis for peripheral blood mononuclear cells (PBMCs) collected from 4 COVID-19 patients at 4 different time points from symptom onset to recovery. We found that PBMCs at different COVID-19 disease stages exhibited unique transcriptome characteristics. SARS-CoV-2 infection dysregulated innate immunity especially type I interferon response as well as the disturbed release of inflammatory cytokines and lipid mediators, and an aberrant increase of low-density neutrophils may cause tissue damage. Activation of cell death, exhaustion and migratory pathways may lead to the reduction of lymphocytes and dysfunction of adaptive immunity. COVID-19 induced hypoxia may exacerbate disorders in blood coagulation. Based on our analysis, we proposed a set of potential biomarkers for monitoring disease progression and predicting the risk of severity.