Characterization of pathogen-inactivated COVID-19 convalescent plasma and responses in transfused patients

Abstract

Background: Efficacy of donated COVID-19 convalescent plasma (dCCP) is uncertain and may depend on antibody titers, neutralizing capacity, timing of administration, and patient characteristics.

Study design and methods: In a single-center hypothesis-generating prospective case-control study with 1:2 matched dCCP recipients to controls according to disease severity at day 1, hospitalized adults with COVID-19 pneumonia received 2 × 200 ml pathogen-reduced treated dCCP from 2 different donors. We evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in COVID-19 convalescent plasma donors and recipients using multiple antibody assays including a Coronavirus antigen microarray (COVAM), and binding and neutralizing antibody assays. Outcomes were dCCP characteristics, antibody responses, 28-day mortality, and dCCP -related adverse events in recipients.

Results: Eleven of 13 dCCPs (85%) contained neutralizing antibodies (nAb). PRT did not affect dCCP antibody activity. Fifteen CCP recipients and 30 controls (median age 64 and 65 years, respectively) were enrolled. dCCP recipients received 2 dCCPs from 2 different donors after a median of one hospital day and 11 days after symptom onset. One dCCP recipient (6.7%) and 6 controls (20%) died (p = 0.233). We observed no dCCP-related adverse events. Transfusion of unselected dCCP led to heterogeneous SARS CoV-2 antibody responses. COVAM clustered dCCPs in 4 distinct groups and showed endogenous immune responses to SARS-CoV-2 antigens over 14-21 days post dCCP in all except 4 immunosuppressed recipients.

Discussion: PRT did not impact dCCP anti-virus neutralizing activity. Transfusion of unselected dCCP did not impact survival and had no adverse effects. Variable dCCP antibodies and post-transfusion antibody responses indicate the need for controlled trials using well-characterized dCCP with informative assays.

Keywords: COVID-19; COVID-19 convalescent plasma; SARS-CoV2; neutralizing antibodies; pathogen-reduction treatment.

FIGURE 1

dCCP antibodies to SARS‐CoV‐2 S1 and N antigens, nAbs by ADAP, ACE‐2 blocking nAb and RVPVN NT₅₀ assays before and after PRT. The upper 2 figures show Anti ‐S and anti‐N activity in dCCP before and after PRT expressed as ∆Ct by ADAP assay (ADAP S1 Ab and ADP N Ab). The lower 2 figures show dCCP virus neutralization before and after PRT by ACE‐2 blocking Ab assay expressed as ∆Ct PCR assay and RVPN NT₅₀ before and after PRT.

FIGURE 2

Donor CCP profiles after PRT by COVAM PCA using 11 SARS‐co‐V‐2 antigens. Principal component analysis (PCA) of plasma reactivity with 11 SARS‐CoV‐2 antigens (Unique ID), determined by COVAM shows the spatial distribution of the CCP along the first and second principal components and revealed four clusters.: non‐reactive (cluster 1 ‐ black); broad reactivity to all antigens (cluster 2 ‐ red); Intermediate reactivity primarily S reactive with lower reactivity to N (cluster 3 ‐ blue); and intermediate reactivity primarily to N with lower reactive to the other antigens (cluster 4 ‐ yellow). The large symbols within each cluster represent the mean values. [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 3

Correlation of the different antibody assays used to assess PRT dCCP. Correlation of S1 ADAP Ab with neutralizing activity (ACE‐2 blocking nAbs) expressed as ∆Ct PCR cycle time (A). Correlation of RVPN NT₅₀ titer expressed as log₁₀ with neutralizing activity (ACE‐2 blocking nAbs) expressed as ∆Ct PCR cycle time (B). Correlation of S1 IgG Ab measured by Euroimmun with S1 ADAP Ab expressed as ∆Ct PCR cycle time (C). Correlation of S1 IgG Ab measured by Euroimmun with −2 blocking nAbs expressed as ∆Ct PCR cycle time (D). Respective R² values are indicated for each analysis.

FIGURE 4

Correlation of COVAM PCA with S1 ADAP ab, ACE‐2 blocking nAb, and RVPN NT₅₀ for 13 CCP transfused to recipients. dCCP ADAP anti‐S, and nAb by RVPN assay and ADAP ACE‐2 inhibition assay according to COVAM PCA Group. Thirteen dCCP were used for transfusion of recipients with acute COVID‐19 infection. [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 5

dCCP recipient baseline and serial plasma antibodies to IgG S and N proteins by commercial assay. Recipient IgG antibody to S and N were measured in recipient plasma samples at baseline (BL) and after CCP transfusion on days (D) 1, 3, 7, and 14. S1 IgG Ab was measured using Euroimmun ELSA and N IgG Ab by Roche ELISA assay. Immune suppressed recipients are noted in red. [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 6

dCCP recipient antibodies to SARS‐CoV‐2 at baseline and one day after transfusion. NAb was measured in recipients before dCCP transfusion (Day 0 or −1) and the day after dCCP transfusion (Day 1). Antibody neutralizing activity was determined by RVPN NT₅₀, and ACE‐2 blocking nAb assay and total S1 ADAP Ab expressed as ∆Ct.