Evaluation of three fully-automated SARS-CoV-2 antibody assays.

Objectives Serological assays for detection of SARS-CoV-2 antibodies are increasingly used during the COVID-19 pandemic caused by the SARS-Coronavirus-2. Here we evaluated the analytical and clinical performance of three commercially available SARS-CoV-2 antibody assays. Methods A total of 186 samples from 58 patients with PCR-confirmed COVID-19 infection were measured using SARS-CoV-2 antibody assays by Siemens Healthineers, Roche Diagnostics and Euroimmun. Additionally, 123 control samples, including samples collected before December 2019 and samples with potential cross-reactive antibodies were analyzed. Diagnostic specificity, sensitivity, agreement between assays and ROC curve-derived optimized thresholds were determined. Furthermore, intra- and inter-assay precision and the potential impact of interfering substances were investigated. Results SARS-CoV-2 antibody assays by Siemens and Roche showed 100% specificity. The Euroimmun assay had 98 and 100% specificity, when borderline results are considered as positive or negative, respectively. Diagnostic sensitivity for samples collected ≥14 days after PCR-positivity was 97.0, 89.4 and 95.5% using the Siemens, Roche and Euroimmun assay, respectively. Sensitivity of the Roche assay can be increased using an optimized cut-off index (0.095). However, a simultaneous decrease in specificity (98.4%) was observed. Siemens showed 95.8 and 95.5% overall agreement with results of Euroimmun and Roche assay, respectively. Euroimmun and Roche assay exhibited 92.6% overall agreement. Discordant results were observed in three COVID-19 patients and in one COVID-19 patient none of the investigated assays detected antibodies. Conclusions The investigated assays were highly specific and sensitive in detecting SARS-CoV-2 antibodies in samples obtained ≥14 days after PCR-confirmed infection. Discordant results need to be investigated in further studies.

Factors influencing the virological testing of cornea donors.

To assess the influence of donor, environment, and logistical factors on the results of virological testing of blood samples from cornea donors.Data from 670 consecutive cornea donors were analyzed retrospectively. Logistic regression analysis was used to assess the influence of different factors on the results of virological testing of blood samples from cornea donors.The mean annual rate of donors with serology-reactive or not evaluable result was 14.8% (99 of 670) (range 11.9%-16.9%). The cause of donor death by cancer increased the risk of serology-reactive or not evaluable result (P = .0300). Prolonged time between death and post mortem blood removal was associated with a higher rate of serology-reactive or not evaluable result (P < .0001). Mean monthly temperature including warmer months, differentiating between septic and aseptic donors, sex, and donor age had no significant impact on the results of virological testing of blood samples from cornea donors.The cause of donor death by cancer and a prolonged time between death and post mortem blood removal seem to be mainly responsible for serology-reactive or not evaluable result of blood samples from cornea donors. The percentage of discarded corneas caused by serology-reactive or not evaluable result may be reduced by shortening the period of time between death and post mortem blood removal.

Evidence of multiple hepatitis virus infections in autopsied materials of intravenous drug addicts.

Injection of illicit drugs is an important risk factor for acquiring parenterally transmitted viral infections. To investigate the prevalence of viral mono- and co-infections in intravenous drug uses (IDUs) postmortem and to evaluate the risk of potential infection to personnel involved in medicolegal practice a total number of 59 known IDUs were tested during necropsy for serological markers of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) as well as for the nucleic acids of the hepatitis B and C viruses, and the GB virus C (GBV-C), in blood and in the liver. Our findings showed that 90.2% cases were positive for at least one or more serological markers of the tested viruses. Seroprevalence rates of anti-HCV, HBsAg and anti-HIV were 78.4%, 32.4% and 29.7% respectively. Of the IDUs tested for serological infection markers 43.2% were positive for one, 40.5% for two and 5.4% for all three markers. Viral nucleic acids were detected in the sera of 64.4% and in the liver of 81.4% of the cases. HCV, RNA, GBV-C RNA and HBV DNA were found in 33.9%, 28.8% amd 28.8% of the serum samples and in 67.8%, 35.6% and 28.8% of the liver tissue, respectively. Active viral co-infections or triple infections were detectable in the sera of 20.3% and in the liver of 39% of the case. Results show that the sensitivity of viral nucleic acid testing postmortem strongly depends on the quality and source of material used.

Infectious risk factors for atherosclerotic vascular disease in hemodialysis patients--Chlamydia pneumoniae but not Helicobacter pylori or cytomegalovirus is associated with increased C-reactive protein.

BACKGROUND: Cardiovascular disease is a major problem in patients with chronic renal failure leading to increased mortality. Several infectious agents have been implicated to be associated with atherosclerosis. We were interested to evaluate whether there is a correlation between a past infection with Chlamydia pneumoniae (Cpn), Helicobacter pylori (Hp) or cytomegalovirus (CMV) and the manifestation of a symptomatic atherosclerotic disease in patients with endstage renal failure. METHODS AND RESULTS: Patients (n=267) on hemodialysis were investigated. In 101 patients with an apparent atherosclerotic disease (case group) increased IgA levels against Cpn were found (p < or = 0.0001 vs. controls; n=33). Nearly 45% of the case group had a history of myocardial infarction (MI) (p < or = 0.0001). Prior stroke was found in about 30% of patients in the case group (p < or = 0.002). Elevated CRP levels were identified as an independent risk factor for atherosclerosis in all groups. IgA seropositivity against Cpn correlated with elevated CRP values for all atherosclerotic patients (p < or = 0.001), especially in the group of patients with MI (p < or = 0.019) and peripheral vascular disease (p < or = 0.005). There was no correlation between CMV (IgG, IgM) or Hp (IgA, IgG) seropositivity and atherosclerotic disease. CONCLUSION: IgA seropositivity for Cpn and elevated CRP values but not Hp or CMV was associated with an increased rate of symptomatic atherosclerotic manifestations as MI, stroke, cerebral or peripheral atherosclerosis in patients with endstage renal disease on hemodialysis.