Search

Xiumei Hu,1,* Changmeng Wu,1,* Bo Situ,1,* Peifu Tian,2,* Taixue An,1 Qiang Li,1 Weilun Pan,1 Ruyi Zhang,1 Biao Yang,3 Dehua Sun,1 Yuhai Hu,2 Qian Wang,1,3 Lei Zheng1 1Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People’s Republic of China; 2Department of Medicine Laboratory, Hankou Hospital of Wuhan, Wuhan 430010, People’s Republic of China; 3Department of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510280, People’s Republic of China*These authors contributed equally to this workCorrespondence: Lei Zheng; Qian Wang Email nfyyzhenglei@smu.edu.cn; wangqian@smu.edu.cnObjective: The coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is now rapidly spreading globally. Serological tests are an important method to assist in the diagnosis of COVID-19, used for epidemiological investigations. In this study, we aimed to investigate the impact of different types of vacuum collection tubes on the detection of SARS-CoV-2 IgM and IgG antibodies, using the colloidal gold immunochromatographic assay (GICA).Patients and Methods: A total of 112 patients with COVID-19 and 200 healthy control subjects with no infection were enrolled in this study. Their serum and plasma were collected into four different types of vacuum blood collection tubes. SARS-CoV-2 IgM and IgG specific antibodies in the plasma and serum were then detected by GICA and chemiluminescence assay (CA), respectively. In addition, the particle sizes of different colloidal gold solutions in the presence of different anticoagulants and coagulants were evaluated by both laser diffraction (Malvern) and confocal laser microscope, respectively.Results: Our results revealed that anticoagulated plasma with EDTA-K2 improved the positive detection rate of SARS-CoV-2 IgM antibodies. Furthermore, our results shown that the detection results by GICA and CA were highly consistent, especially, the results of EDTA-K2 anticoagulated plasma detected by GICA was more consistent with CA results. We confirmed that EDTA-K2 could improve the detection sensitivity of SARS-CoV-2 IgG antibodies by chelating excessive colloidal gold compared with sodium citrate or lithium heparin, these methodologies did not appear to cause false positives. Colloidal gold particles could be chelated and aggregated by EDTA-K2, but not by sodium citrate, lithium heparin and coagulants.Conclusion: GICA is widely used to detect antibodies for the advantages of convenient, fast, low cost, suitable for screening large sample and require minimal equipment. In this study, we found that EDTA-K2 amplified the positive antibody signal by chelating colloidal gold and improved the detection sensitivity of SARS-CoV-2 IgM and IgG antibodies when using the GICA. Therefore, we suggested that EDTA-K2 anticoagulated plasma was more suitable for the detection of SARS-CoV-2 antibodies.Keywords: EDTA-K2, SARS-CoV-2, antibodies, gold immunochromatographic assay; GICA

Background: The data of antiviral therapy throughout the entire pregnancy are relatively scarce. The aim of the present study was to evaluate the safety and efficacy of antiviral therapy for chronic HBV infection throughout the entire pregnancy. Methods: This was a single-center, prospectively study. Fifty-five women received antiviral therapy (TDF or LDT) from pre-conception to the entire pregnancy. Sixty-four women did not receive antiviral therapy during pre-conception and the entire pregnancy. All infants in the two groups had received immunoprophylaxis on schedule. Mother-infant pairs were followed up at least 7 months postpartum. The outcome was the safety and efficacy of antiviral therapy for mothers and offspring. Findings: All mothers tolerated antiviral therapy (TDF or LDT) well. The mean maternal HBV DNA level in the antiviral therapy group was less than that of the control group before delivery as well as in the three months postpartum (P 0.05). Furthermore, there was not a statistically significant difference in the birth weight, the birth length, and the congenital diseases of infants between the two groups, respectively (P>0.05). In 7 months postpartum, none of infants who tested HBV status in the two groups was positive for HBsAg. Interpretation: Antiviral therapy (TDF or LDT) from pre-conception to the entire pregnancy could be safe and effective for pregnant women with HBV infection and their fetuses/ infants. Trial Registration: The present study was registered in ClinicalTrials.gov (No. NCT03181607). Funding Statement: The present study was funded by the National Key Research and Development Program of China (2017YFC1001402, 2018YFC1002900), National Natural Science Foundation of China (81401306, 81830045), Clinical Research Project of Guangzhou Medical University (No. 2017[160]) and Sino-German Center for Research Promotion (SGC)'s Rapid Response Funding Call for Bilateral Collaborative Proposals between China and Germany in COVID-19 Related Research (No. C-0032). Declaration of Interests: All authors declare no financial, potential personal or commercial conflict of interest. Ethics Approval Statement: The present study was approved by the Institutional Ethics Committee of the Third Affiliated Hospital of Guangzhou Medical University, and was carried out in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Informed written consent was obtained from each participant in the present study.