Impact of pathogen reduction methods on immunological properties of the COVID‐19 convalescent plasma

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Abstract

COVID‐19 convalescent plasma is an experimental treatment against SARS‐CoV‐2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS‐CoV2 in convalescent plasma.

Materials and methods

A total of 140 plasma doses collected by plasmapheresis from COVID‐19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS‐CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S‐ and N‐proteins of SARS‐CoV‐2 were measured before and after pathogen reduction.

Results

The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one‐step (two‐step, respectively) decrease. Paired two‐sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment.

Conclusion

Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID‐19 convalescent plasma compared to riboflavin.

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  1. SciScore for 10.1101/2020.10.02.20205567: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: Ethical approval was granted for this study by the Independent Moscow City Research Ethical Committee in accordance with national regulations.
    Consent: Informed consent was obtained in writing from all donors prior to donation.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    After washing the plates 5x the peroxidase-conjugated anti-human IgG detection antibodies diluted in blocking solution were added and plates were incubated at 37°C for 1 h.
    anti-human IgG
    suggested: None
    The CL-series SARS-CoV-2 IgG and IgM assays are a two-step chemiluminescent immunoassays for detection of IgG and IgM SARS-CoV-2 antibodies in human serum or plasma, performed on the fully automated Mindray CL 1200i analytical system (Shenzhen Mindray Bio-Medical Electronics Co., Shenzen, China).
    SARS-CoV-2 IgG
    suggested: None
    IgM SARS-CoV-2
    suggested: None
    Alkaline phosphatase-labeled anti-human IgG or IgM monoclonal antibodies are added to the reaction to form a sandwich with microparticles captured anti-SARS-CoV-2 antibodies.
    IgM
    suggested: None
    anti-SARS-CoV-2
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Serial 10-fold dilutions of the virus stock were prepared in DMEM with 2% heat- inactivated FBS and in volume of 100 µl were added to Vero E6 cells in a 96-well plate in 8 repeats.
    Vero E6
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).


    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.


    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.


    Results from JetFighter: We did not find any issues relating to colormaps.


    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.