Profiling antibody response patterns in COVID-19:Spike S1-reactive IgA signature in the evolution of SARS-CoV-2 infection
DOI for this manuscript is: 10.3389/fimmu.2021.772239 Published in 2021 by Lucia Lopalco et al. We have investigated in a new statistical perspective the antibody responses to SARS-CoV-2 in 141 COVID-19 patients exhibiting a broad range of clinical manifestations (as described in raw data of all clinical data both at time of entry and followup. Two files are associated to hospitalized -so called COVID patients- and 2 files at pauci/asymptomatic subjects -so called as RSA-) . This cohort accurately reflects the characteristics of the first wave of the SARS-CoV-2 pandemic in Italy. We determined the IgM, IgA and IgG levels towards SARS-CoV-2 S1, S2, and NP antigens, evaluated their neutralizing activity and relationship with clinical signatures (as shown in the same raw data of clinical data). Moreover, we longitudinally followed 72 patients up to 9 months post symptoms onset to study the persistence of antibodies levels (raw data showing follow up of the studied subjects). Our results showed that the majority of COVID-19 patients developed an early virus-specific antibody response. The magnitude and the neutralizing properties of the response was heterogeneous regardless the severity of the disease. Antibody levels dropped over time, even though spike reactive IgG and IgA were still detectable up to 9 months. Early baseline antibody levels were key drivers of the subsequent antibody production and the long-lasting protection against SARS-CoV-2. Importantly, we identified anti-S1 IgA as a good surrogate marker to predict the clinical course of COVID-19. In addition analyses have been performed in purified IgG and IgA fraction of some subjects as shown in panel D of Fig 1 of the manuscript, the relative file with raw data is called IC50 purified fractions. Detailed description of the findings is reported in the published manuscript.