False positive serology of prepandemic chagasic samples with SARS‐CoV‐2 antigen

Abstract

Objective: To determine whether prepandemic sera from patients with Chagas disease recognise SARS-CoV-2 antigens. Materials and Methods: Forty sera from patients with Chagas disease were tested for the presence of IgG cross-reactivity against the nucleocapsid protein (NP) and spike (S) SARS-CoV-2 proteins by ELISA. Positive samples were tested again using a different ELISA and CLIA, both against NP. Results: None of the sera from patients with Chagas disease, previously confirmed as positive for the presence of anti-Trypanosoma cruzi antibodies reacted against the SARS-CoV-2 S protein, and six samples tested positive for the NP antigen (15%). The six positive samples were re-tested, five remained positive by ELISA and all were negative by CLIA. Conclusion: According to our data, false-positive results might be a concern in the detection of SARS-CoV-2 antibodies in patients with Chagas disease.

Malaria and other infections induce polyreactive antibodies that impact SARS‐CoV‐2 seropositivity estimations in endemic settings

“…37 A study with 40 sera from patients with Chagas disease and presence of anti-Trypanosoma cruzi antibodies showed 6 sera reacting to SARS-CoV-2 N protein (15% false positives). 38 Schistosoma, dengue virus and T. cruzi are also known to trigger polyclonal B-cell activation leading to abnormalities in immunoglobulin secretion that can contribute to the production of antibodies, which could cause false-positive reactions in antigen-antibody tests. 34,35,39,40 The oxidized hemoglobin derived from the hemolysis that occurs in some infections, like malaria, dengue, and Chagas disease, modifies the antigen-binding characteristics of IgG, also triggering IgG polyreactivity and autoreactivity.…”

COVID‐19: Prevention, Detection, and Treatment by Using Carbon Nanotubes‐Based Materials

“…[126] While most of the available rapid diagnostic tools show commercial success, developing a more sensitive, rapid, and accurate COVID-19 test can be challenging, especially in overcoming false-positive and falsenegative issues. [127] While reverse transcription-PCR (RT-PCR) test based on the molecular genetic assay method is widely used for accurate COVID-19 detection, the test results are slow. [128] Other promising methods include nucleic acid amplification assays, serological and immunological tests, and chest CT scans also exist.…”

“…To date, there are a wide variety of commercially available test kits for detecting COVID‐19 [126] . While most of the available rapid diagnostic tools show commercial success, developing a more sensitive, rapid, and accurate COVID‐19 test can be challenging, especially in overcoming false‐positive and false‐negative issues [127] . While reverse transcription‐PCR (RT‐PCR) test based on the molecular genetic assay method is widely used for accurate COVID‐19 detection, the test results are slow [128] .…”

“…[129] This shortcoming can be addressed using better, cost-effective diagnostic methods to rapidly screen viral infections. [127] Besides that, an immunological assay technique called Enzyme-Linked Immunosorbent Assay (ELISA) to detect specific antibodies or antigens is also widely used. However, expensive instruments and properly trained, qualified personnel are needed to analyze the sample.…”

“…Other promising methods include nucleic acid amplification assays, serological and immunological tests, and chest CT scans also exist [129] . This shortcoming can be addressed using better, cost‐effective diagnostic methods to rapidly screen viral infections [127] …”