1/11 Analysis of humoral immune response in #COVID19 patients provides key insights for #ConvalescentPlasma therapy and #Vaccine research: https://www.medrxiv.org/content/10.1101/2020.03.30.20047365v1

2/11 A pseudotyped-lentiviral-vector-based neutralization assay was used to measure SARS-CoV-2-specific neutralizing antibodies (NAbs) in plasma from recovered COVID-19 patients with mild symptoms

3/11 ~30% of COVID19-recovered patients failed to develop high titers of neutralizing antibodies despite similar disease duration, suggesting key role of T-cells or cytokines in immune response

6/11 Neutralizing antibody titers of COVID-19 patients collected two weeks post-discharge did not significantly differ from those collected at the time of discharge

10/11 Limitations:
-Current lack of peer review (pre-print)
-Lack of information about the kinetics of viral loads (lacked respiratory specimens)
-Patients in severe and critical condition were excluded from the study (received passive antibody treatment before sample collection)

11/11 Concerns, commentary, and questions welcomed at this crucial stage of the #ConvalescentPlasma therapy effort @CCPP19 @ACasadevall1 @AlexAndersonMD @DrMJoyner @cshperspectives @VPrasadMDMPH @vincentRK @medrxivpreprint #coronavirus

4/11 Older COVID19-recovered patients demonstrated higher titers of both neutralizing and spike-binding #SARSCoV2-specific #antibodies

5/11 Temporal analysis of COVID19 antibody titers shows humoral immune response ramping up on day 10-15 post-onset of disease

7/11 NAb titers in ten of the 175 recovered patients were below limit of detection despite lab-confirmed infection with SARS-CoV-2

9/11 Despite 77.2% identical amino acids between SARS-CoV-2 and SARS-CoV spike proteins and cross-binding potential, COVID-19 convalescent plasma did NOT neturalize SARS-CoV, suggesting differences between #SARSCoV2 and #SARSCoV #epitopes and #immunogenicity

8/11 NAb titers negatively correlated with blood lymphocyte counts and positively correlated with blood CRP levels, suggesting that the humoral response might play an important role when cellular response is dysfunctional or impaired.