Abstract
Patients with COVID-19 who develop platelet-activating antibodies represent a subset at heightened thrombotic risk, yet the immune features associated with this response remains to be defined. We applied single-cell RNA-seq of B and T cells, single B cell V(D)J-seq, and plasma cytokine and chemokine analysis to define immune signatures distinguishing patients who did (PEA+) or did not (PEA–) develop these antibodies. Patients positive for PEA showed prominent transcriptional enrichment of inflammatory, antigen presentation, and B cell receptor signaling pathways within antigen-experienced B cell subsets. Expanded B cell clones in patients positive for PEA were disproportionately enriched within atypical memory B cells and exhibited upregulated IFN-γ–response signatures, increased proliferative mutational patterns, limited class switching, and a significant overrepresentation of RKH/Y5 heavy-chain motifs associated with platelet-activating antibodies, consistent with an extrafollicular-biased response. Parallel T cell profiling revealed IL-12 pathway enrichment across most T cell subsets, increased IFN-γ transcription, and elevated plasma levels of Th1-associated cytokines in patients positive for PEA. Collectively, these data highlight a coordinated inflammatory environment marked by Th1-skewed T cell activation and selective expansion of atypical memory B cell clones carrying RKH/Y5 motifs, defining immunologic features associated with platelet-activating antibody development in COVID-19.
Authors
Nathan Witman, Mei Yu, Yuqi Zhang, Kexin Gai, Yuhong Chen, Lu Zhou, Christine Nguyen, Wen Zhu, Yongwei Zheng, Shawn Jobe, Mary Beth Graham, Weiguo Cui, Demin Wang, Renren Wen
Figure 2
Elevated inflammatory pathway expression in PEA+ patients.
