Proteome profiling of home-sampled dried blood spots reveals proteins of SARS-CoV-2 infections

  1. Claudia Fredolini
  2. Tea Dodig-Crnković
  3. Annika Bendes
  4. Leo Dahl
  5. Matilda Dale
  6. Vincent Albrecht
  7. Cecilia Mattsson
  8. Cecilia E. Thomas
  9. Åsa Torinsson Naluai
  10. Magnus Gisslen
  11. Olof Beck
  12. Niclas Roxhed
  13. Jochen M. Schwenk

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Abstract

Background

Self-sampling of dried blood spots (DBS) offers new routes to gather valuable health-related information from the general population. Yet, the utility of using deep proteome profiling from home-sampled DBS to obtain clinically relevant insights about SARS-CoV-2 infections remains largely unexplored.

Methods

Our study involved 228 individuals from the general Swedish population who used a volumetric DBS sampling device and completed questionnaires at home during spring 2020 and summer 2021. Using multi-analyte COVID-19 serology, we stratified the donors by their response phenotypes, divided them into three study sets, and analyzed 276 proteins by proximity extension assays (PEA). After normalizing the data to account for variances in layman-collected samples, we investigated the association of DBS proteomes with serology and self-reported information.

Results

Our three studies display highly consistent variance of protein levels and share associations of proteins with sex (e.g., MMP3) and age (e.g., GDF-15). Studying seropositive (IgG + ) and seronegative (IgG - ) donors from the first pandemic wave reveals a network of proteins reflecting immunity, inflammation, coagulation, and stress response. A comparison of the early-infection phase (IgM + IgG - ) with the post-infection phase (IgM - IgG + ) indicates several proteins from the respiratory system. In DBS from the later pandemic wave, we find that levels of a virus receptor on B-cells differ between seropositive (IgG + ) and seronegative (IgG - ) donors.

Conclusions

Proteome analysis of volumetric self-sampled DBS facilitates precise analysis of clinically relevant proteins, including those secreted into the circulation or found on blood cells, augmenting previous COVID-19 reports with clinical blood collections. Our population surveys support the usefulness of DBS, underscoring the role of timing the sample collection to complement clinical and precision health monitoring initiatives.

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  1. Version published to 10.1038/s43856-024-00480-4
  2. ScreenIT

    SciScore for 10.1101/2021.11.15.21266315: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: Individuals who volunteered to participate in the study were asked to perform self-sampling according to the instructions and return the filled sampling card, questionnaire, and consent form by regular mail.
    IRB: The study was approved by the regional ethical board (EPN Stockholm, Dnr 2015/867-31/1) and the Swedish Ethical Review Authority (EPM, Dnr 2020-01500).
    Sex as a biological variablenot detected.
    RandomizationPopulation study: Capillary blood samples from the general population were obtained by cold-mailing home-sampling kits (MM20-009-01, Capitainer AB, Sweden) to 2000 randomly selected individuals (20-74 years old) in metropolitan Stockholm (Tables 1. and 2.) during April 2020 together with a questionnaire, as described previously (16).
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line AuthenticationAuthentication: Capillary blood samples were obtained by finger-pricking and applying blood droplets onto a quantitative DBS sampling card (qDBS, Capitainer AB, Stockholm, Sweden) according to the supplier’s instructions.

    Table 2: Resources

    Antibodies
    SentencesResources
    Correlations between the determine protein levels and IgG or IgM antibody levels detected against S, RBD, and N antigens in population samples (separately per set, N = 78 and N = 66) were computed using the “corr.test” function of the “psych” R package (version 1.9.12.31).
    IgM
    suggested: None

    Results from OddPub: Thank you for sharing your code and data.

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    The observed increase in levels of circulating CHRDL2 may support recent findings of an active role of bone marrow as immune regulatory organ and indicate active proliferation of cells involved in adaptive immune response (38) An inherent limitation of studying DBS samples is the need for very sensitive methods for quantification. (9). In this study we chose to focus on stable proteins occurring at medium to high abundance levels in the circulation. Indeed, the recommended dilution for plasma for the three assay panels used is 1:100, 1:20, or 1:2025. Such dilutions could be easily coupled to the blood dilution implicit in the procedure of protein elution from DBS (see Material and Methods). Consequently, next efforts aim to establish procedures to quantify proteins of lower abundance, such as IL6 or TNF, as well as other inflammatory biomarkers discussed in the literature. Moreover, since the chosen method build on pre-selected panels of proteins, we could have missed some relevant markers described covered in current COVID-19 literature (39). As population samples were collected in an anonymous manner from a set of random households, no follow-up of the participating donors will be possible and new studies must be designed where additional samples and clinical information can be collected over a longer period. Even though we observed associations between serostatus and proteins, there could be unknown factors, such as BMI, medication, travel, or socio-economic factors as wel...

    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.

    Results from scite Reference Check: We found no unreliable references.

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  3. Version published to 10.1101/2021.11.15.21266315 on medRxiv