Prevalence of anti-lymphocyte IgM autoantibodies driving complement activation in COVID-19 patients. 

 -  2024 
<br/><br/> Discussion: IgM ALAb and complement activation against lymphocytes may contribute to the acute lymphopenia observed in COVID-19 patients. Copyright © 2024 Perez-Diez, Liu, Calderon, Bennett, Lisco, Kellog, Galindo, Memoli, Rocco, Epling, Laidlaw, Sneller, Manion, Wortmann, Poon, Kumar and Sereti.  Introduction: COVID-19 patients can develop autoantibodies against a variety of secreted and membrane proteins, including some expressed on lymphocytes. However, it is unclear what proportion of patients might develop anti-lymphocyte antibodies (ALAb) and what functional relevance they might have.  Methods: We evaluated the presence and lytic function of ALAb in the sera of a cohort of 85 COVID-19 patients (68 unvaccinated and 17 vaccinated) assigned to mild (N=63), or moderate/severe disease (N=22) groups. Thirty-seven patients were followed-up after recovery. We also analyzed in vivo complement deposition on COVID-19 patients' lymphocytes and examined its correlation with lymphocyte numbers during acute disease.  Results: Compared with healthy donors (HD), patients had an increased prevalence of IgM ALAb, which was significantly higher in moderate/severe disease patients and persisted after recovery. Sera from IgM ALAb+ patients exhibited complement-dependent cytotoxicity (CDC) against HD lymphocytes. Complement protein C3b deposition on patients' CD4 T cells was inversely correlated with CD4 T cell numbers. This correlation was stronger in moderate/severe disease patients. 
<br/><br/><br/>English 
<br/><br/><label>ISSN: </label>1664-3224 
<br/><br/><label>Standard No.: </label>PMC11061367 [pmc] 
<br/><br/><label>Subjects--Topical Terms: </label><br/>*Autoantibodies<br/>*Complement Activation<br/>*COVID-19<br/>*Immunoglobulin M<br/>*SARS-CoV-2<br/>Adult<br/>Aged<br/>Autoantibodies/bl [Blood]<br/>Autoantibodies/im [Immunology]<br/>CD4-Positive T-Lymphocytes/im [Immunology]<br/>Complement Activation/im [Immunology]<br/>Complement C3b/im [Immunology]<br/>COVID-19/bl [Blood]<br/>COVID-19/im [Immunology]<br/>Female<br/>Humans<br/>Immunoglobulin M/bl [Blood]<br/>Immunoglobulin M/im [Immunology]<br/>Lymphocytes/im [Immunology]<br/>Lymphopenia/bl [Blood]<br/>Lymphopenia/im [Immunology]<br/>Male<br/>Middle Aged<br/>Prevalence<br/>SARS-CoV-2/im [Immunology]--Automated
<br/><br/><label>Subjects--Geographic Terms: </label><br/>MedStar Washington Hospital Center
<br/><br/><label>Index Terms--Occupation: </label><br/>Medicine/Infectious Disease
<br/><br/><label>Index Terms--Function: </label><br/>Journal Article<br/>Research Support, Non-U.S. Gov't