De novo natural anti-M alloantibody emergence in severe Coronavirus Disease 2019

• DOI: 10.1016/j.jiph.2022.10.025
• Publication Date: 2022-11-02T16:20:43Z
• Authors: Robin Jeannet; Alexandra Descazeaud; Thomas Daix; Hélène Pauthier; Virginie Pascal; Sébastien Hantz; Sophie Le Cam; Bruno Francois; Jean Feuillard; Xavier Lafarge
• Keywords: 0301 basic medicine; Erythrocytes; Alloantibody; SARS-CoV-2; [SDV]Life Sciences [q-bio]; Transfusion; Short Communication; M-antigen; 610; COVID-19; Infectious and parasitic diseases; RC109-216; 3. Good health; 03 medical and health sciences; [SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology; Blood Group Antigens; Humans; Public aspects of medicine; RA1-1270

The immune response is a key player in the course of SARS-CoV-2 infection, and is often seriously dysfunctional in severe Coronavirus Disease 2019. The hyperinflammatory status has been described to be accompanied by the appearance of autoantibodies. In a lethal COVID-19 infection, we observed the emergence of a de novo natural alloantibody which targeted the M antigen from the MNS blood group on red blood cells (RBC) without evidence of any cross-reaction with SARS-CoV-2 antigens. This IgM lambda alloantibody was unmutated and unswitched. Here, we describe for the first time the emergence of a bystander de novo natural alloantibody against RBCs in a severe COVID-19 patient, highlighting the extra-follicular humoral response reported in these cases.