SARS-CoV-2 antibody response in SARS survivors with and without the COVID-19 vaccine.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread worldwide. However, it remains unknown whether individuals with prior SARS-CoV-1 infection are protected from SARS-CoV-2 infection. This study assessed protective antibody levels in SARS survivors with and without the COVID-19 vaccine. METHODS: We recruited 17 SARS survivors infected with SARS-CoV-1 in 2003, including 8 not vaccinated with the COVID-19 vaccine and 9 vaccinated with two doses of inactivated whole-virion COVID-19 vaccine (Sinopharm). In addition, 105 healthy adult volunteers without SARS-CoV-1 and SARS-CoV-2 infections were used as controls. The relative concentrations of three protective antibodies including anti-SARS-CoV-2 spike IgG (nCoV S-IgG), anti-SARS-CoV-2 spike receptor-binding domain IgG (nCoV RBD-IgG), and anti-SARS-CoV-2 neutralizing antibodies (nCoV NAbs) were measured to evaluate humoral immunity. RESULTS: We found that the positive rates of these antibodies in unvaccinated SARS survivors were 37.5%, 37.5%, and 62.5%, respectively. In contrast, the corresponding positive rates were all 0% in controls before vaccination. In controls, the levels of protective antibodies reached a peak ca. 28 days after the second dose of vaccine and then started to decline. Surprisingly, the levels of these antibodies were maintained at very high levels even 166 days after the second dose of vaccine in SARS survivors. CONCLUSION: Our study suggests that there are protective antibodies cross-reacting with SARS-CoV-2 in recovered SARS patients and that SARS survivors can generate a much stronger antibody response induced by the COVID-19 vaccine than can controls. These initial findings show the feasibility of developing novel pan-sarbecovirus vaccines.

A Serum Metabolite Classifier for the Early Detection of Type 2 Diabetes Mellitus-Positive Hepatocellular Cancer.

Type 2 diabetes mellitus (T2DM) has been identified as an independent risk factor for hepatocellular cancer (HCC). However, there are no ideal biomarkers for the surveillance and early detection of HCC in the T2DM population at present. In this study, we aimed to explore novel metabolite biomarkers for T2DM-positive [T2DM(+)] HCC by metabolomic analysis. At first, many serum metabolites were found dysregulated in T2DM(+) HCC patients in untargeted metabolomic analyses. Targeted metabolite analyses confirmed that serum benzoic acid and citrulline were increased, and creatine was decreased in T2DM(+) HCC compared to the T2DM group. A metabolite classifier including benzoic acid, creatine, and citrulline was identified as a novel biomarker for the diagnosis of T2DM(+) HCC, with an area under the ROC curve (AUC) of 0.93 for discriminating T2DM(+) HCC patients from T2DM patients. In addition, the metabolite classifier detected small-size (AUC = 0.94), early-stage (AUC = 0.94), and AFP-negative (AUC = 0.96) tumors with high sensitivity and specificity. The combination of this metabolite classifier and AFP might be useful in the surveillance and early detection of HCC in the T2DM population. In conclusion, this study establishes a novel diagnostic tool for T2DM(+) HCC.

Evaluation of three automated Treponema pallidum antibody assays for syphilis screening.

The accuracy of the test is critical for the syphilis serology diagnosis. This study aims to evaluate the values of the Elecsys syphilis assay, the Architect syphilis assay, and the Mindray syphilis assay, as syphilis screening tests for pregnant women and patients with syphilis or other diseases. A reverse algorithm was used for the syphilis serology diagnosis. Serum samples (n = 584) were tested with three automated screening assays. All reactive sera by one, two, or three screening assays were further analyzed with the tolulized red unheated serum test (TRUST). Inconsistent results were confirmed by the Treponema pallidum particle agglutination assay (TPPA). The final patient diagnosis was made according to the results of syphilis serology, clinical evidence, and past medical history. The sensitivity, specificity, accuracy, and kappa value of each assay were as follows: for the Elecsys syphilis assay, 100.0%, 98.5%, 98.6%, and 0.927, respectively; for the Architect syphilis assay: 100.0%, 94.5%, 95.0%, and 0.770; and for the Mindray syphilis assay: 100.0%, 97.0%, 97.3%, and 0.862. The McNemar test showed that there were significant differences in the performance between the Elecsys syphilis assay and the Architect syphilis assay (P < 0.001), and between the Mindray syphilis assay and the Architect syphilis assay (P = 0.001). Our study demonstrated that three automated Treponema pallidum antibody assays generally showed high sensitivities and specificities, and so, they are suitable for use in screening for syphilis. The performances of the Elecsys syphilis assay and the Mindray syphilis assay are superior to Architect syphilis assay.

Performance evaluation of the mindray anti-HCV assay for the detection of hepatitis C virus infection.

BACKGROUND: Anti-hepatitis C virus (anti-HCV) antibody assays are recommended for HCV infection screening. The Mindray anti-HCV assay, based on a third-generation immunoassay, was recently launched in China. We aimed to evaluate its diagnostic performance compared with that of two other widely used assays. METHODS: Six HCV infection seroconversion panels were used to evaluate the sensitivity of the assay for early detection. A total of 1952 clinical samples were tested by the Mindray anti-HCV, Elecsys anti-HCV II, and Architect anti-HCV assays. Samples with reactive results using at least one anti-HCV assay were further tested with the recombinant immunoblot assay (RIBA). Inconsistent results were investigated by the HCV RNA assay and HCV core antigen assay. HCV infection diagnosis was made according to the results of laboratory tests and medical records. RESULTS: The Mindray anti-HCV assay and Elecsys anti-HCV II assay detected seroconversion in an average of 12.5 days and 10.5 days, respectively, and this difference was not significant (P = .818). Of the 1952 cases, 90 were categorized as "HCV infection" and 1862 were categorized as "no HCV infection." The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) of each assay were as follows: the Mindray anti-HCV assay, 95.6%, 99.2%, 85.1%, 99.8%, 118.6 and 0.045, respectively; the Architect anti-HCV assay, 98.9%, 95.2%, 50.0%, 99.9%, 20.69 and 0.012, respectively; and the Elecsys anti-HCV II assay, 96.7%, 99.9%, 98.9%, 99.8%, 1799.9 and 0.033, respectively. There were significant differences in the specificity, PPV and LR+ among the three assays (P < .001). There were no significant differences in the sensitivity, NPV or LR- among the three assays (P > .05). CONCLUSIONS: The Mindray anti-HCV assay displays a similar sensitivity to the Elecsys anti-HCV II assay with respect to the early detection of HCV infection. The Mindray anti-HCV assay shows excellent diagnostic performance and is suitable for the screening of HCV infection.