Author:
Pérez-Díez Ainhoa,Liu Xiangdong,Calderon Stephanie,Bennett Ashlynn,Lisco Andrea,Kellog Anela,Galindo Frances,Memoli Matthew J.,Rocco Joseph M.,Epling Brian P.,Laidlaw Elizabeth,Sneller Mike C.,Manion Maura,Wortmann Glenn W.,Poon Rita,Kumar Princy,Sereti Irini
Abstract
IntroductionCOVID-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.MethodsWe 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.ResultsCompared 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.DiscussionIgM ALAb and complement activation against lymphocytes may contribute to the acute lymphopenia observed in COVID-19 patients.