Lack of neutralizing activity in nonconvalescent sera, regardless of ABO blood group and anti-A isoagglutinin titer

Daniele Focosi; Alfredo Rosellini; Pietro Giorgio Spezia; Lisa Macera; Maria Lanza; Aldo Paolicchi; Denise Biagini; Andreina Baj; Mauro Pistello; Fabrizio Maggi

doi:10.1016/j.jcvp.2021.100035

Lack of neutralizing activity in nonconvalescent sera, regardless of ABO blood group and anti-A isoagglutinin titer

J Clin Virol Plus. 2021 Sep;1(3):100035. doi: 10.1016/j.jcvp.2021.100035. Epub 2021 Aug 8.

Authors

Daniele Focosi¹, Alfredo Rosellini², Pietro Giorgio Spezia³, Lisa Macera^{2

3}, Maria Lanza¹, Aldo Paolicchi^{3

4}, Denise Biagini⁵, Andreina Baj^{6

7}, Mauro Pistello^{2

3}, Fabrizio Maggi^{6

7}

Affiliations

¹ North-Western Tuscany Blood Bank, Pisa University Hospital, Pisa, Italy.
² Division of Virology, Pisa University Hospital, Italy.
³ Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
⁴ Laboratory of Clinical Pathology, Pisa University Hospital, Pisa, Italy.
⁵ Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa, Italy.
⁶ Department of Medicine and Surgery, University of Insubria, Varese, Italy.
⁷ Laboratory of Clinical Microbiology, ASST Sette Laghi, Varese, Italy.

Abstract

Background: Several ABO blood groups have been associated with the likelihood of infection, severity, and/or outcome of COVID-19 in hospitalized cohorts, raising the hypothesis that anti-A isoagglutinins in non-A-group recipients could act as neutralizing antibodies against SARS-CoV-2.

Materials and methods: We run live virus neutralization tests using sera from 58 SARS-CoV-2 seronegative blood donors (27 O-group and 31 A-group) negatives for SARS-CoV-2 IgG to investigate what degree of neutralizing activity could be detected in their sera and eventual correlation with anti-A isoagglutinin titers.

Results: We could not find clinically relevant neutralizing activity in any blood group, regardless of anti-isoagglutinin titer.

Discussion: Our findings suggest that mechanisms other than neutralization explain the differences in outcomes from COVID19 seen in different ABO blood groups.

Keywords: ABO blood group; Anti-A isoagglutinins; COVID-19; Convalescent plasma; Neutralizing antibody; SARS-CoV-2.