Diagnostic performance of an automated chemiluminescence immunoassay for SARS-CoV-2 IgG and IgM antibodies detection: A real life experience

Background

Recently many serological assays for detection of antibodies to SARS-COV-2 virus were introduced on the market. Aim of this study was to assess the diagnostic performance of an automated CLIA for quantitative detection of anti-SARS-CoV-2 IgM and IgG antibodies.

Methods

A total of 354 sera, 89 from consecutive patients diagnosed with COVID-19 (43 mild, 32 severe and 13 critical) and 265 from asymptomatic and negative on rRT-PCR testing healthcare workers, were evaluated for IgM and IgG anti-SARS-CoV-2 antibodies with MAGLUMI immunoassay.

Results

The overall sensitivity and specificity were 86.5% (95%CI: 77.6-92.8) and 98.5% (95%CI:96.2-99.6), respectively. PPV, PPN, LR+, LR- and OR were 95.1 (95%CI: 87.8-98.6), 95.6 (95%CI: 92.4-97.7), 57.3 (95%CI: 21.6-152.1), 7.3 (95%CI: 4.31-12.4) and 418.6 (95%CI: 131.2-1335.2), respectively. The levels of SARS-CoV-2 IgM and IgG antibodies were 1.22 ​± ​1.2 AU/mL and 15.86 ​± ​24.83 AU/mL, 2.86 ​± ​2.4 AU/mL and 69.3 ​± ​55.5 AU/mL, 2.47 ​± ​1.33 AU/mL and 83.9 ​± ​83.9 AU/mL in mild, severe and critical COVID-19 groups, respectively. A significant difference in antibody levels between mild and severe/critical subjects has been shown.

Conclusions

The CLIA assay showed good diagnostic performance and a significant association between antibody levels and severity of the disease was found.

Detection of SARS-CoV-2 in wastewater in Japan during a COVID-19 outbreak

The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater samples has been documented in several countries. Wastewater-based epidemiology (WBE) is potentially effective for early warning of a COVID-19 outbreak. In this study, presence of SARS-CoV-2 RNA in wastewater samples was investigated and was compared with the number of the confirmed COVID-19 cases in the study area during COVID-19 outbreak in Japan. In total, 45 influent wastewater samples were collected from five wastewater treatment plants in Ishikawa and Toyama prefectures in Japan. During the study period, the numbers of confirmed COVID-19 cases in these prefectures increased from 0.3 and 0 to >20 per 100,000 people. SARS-CoV-2 ribonucleic acid (RNA) in the samples was detected using several PCR-based assays. Of the 45 samples, 21 were positive for SARS-CoV-2 according to at least one of the three quantitative RT-PCR assays. The detection frequency increased when the number of total confirmed SARS-CoV-2 cases in 100,000 people exceeded 10 in each prefecture; however, SARS-CoV-2 could also be detected at a low frequency even when the number was below 1.0. SARS-CoV-2 in wastewater could be detected in the early stage of the epidemic, even if the number of confirmed cases potentially underestimates the actual numbers of cases. This suggests that WBE approach can potentially act as an early warning of COVID-19 outbreaks in Japan.

Infusion of HLA-matched and static magnetic field-exposed allogenic lymphocytes treating lymphocytopenia and cytokine storm syndrome: A treatment proposal for COVID-19 patients

Among haematological parameters of patients seriously ill with the coronavirus infectious disease 2019 (COVID-19), leucocytosis, lymphocytopenia, and the abnormal release of circulating cytokines, termed cytokine storm syndrome (CSS, also known as cytokine release syndrome or CRS), were found associated with disease severity. In particular, according to the serum cytokine profiling, pro-inflammatory interleukin 6 (IL-6) and anti-inflammatory interleukin 10 (IL-10) were observed to be considerably higher in patients experiencing respiratory distress, septic shock and/or multi-organ failure, namely "critical cases" requiring intensive care unit (ICU) admission, very often resulting in death. Interestingly, the production of these cytokines from human lymphocytes was found to be modulated by exposure of 24 h to a 554.2-553.8 mT inhomogeneous static magnetic field (SMF), which elicits IL-10 and suppresses IL-6. Thus, herein, with the aim of restoring lymphocyte count and physiological serum levels of IL-6 and IL-10, the infusion of human leukocyte antigen (HLA)-matched and SMF-exposed allogenic lymphocytes is proposed for the first time as an easy and affordable treatment option for COVID-19 patients. Even if the count of lymphocytes in COVID-19 patients is very low, SMF exposure may be a valuable tool for reprogramming autologous lymphocytes towards physiological conditions. Furthermore, the same procedure could be extended to include the whole autologous or allogenic white blood cells (WBCs). Time-varying/pulsed magnetic fields exerting comparable cell effects could also be employed.