Extracellular Vesicle Protein Cargo Reveals Potential Long-Term Biological Impact of Long COVID

Extracellular vesicles (EVs) carry status quo messages across the body that can help decode the long-term impact of Post-Acute Sequelae of SARS-CoV-2 infection (PASC). Here, we analyzed paired peripheral blood mononuclear cell (PBMC)-EVs (pre- and 6–8 months post-infection) collected from a subset of young United States (US) Marines with and without a history of PASC symptoms lasting >30 days post-infection, who participated in the COVID-19 Health Action and Response for Marines (CHARM) studies. Integrated nanospray LC-MS/MS, STRING and Reactome analysis of PBMC-EVs identified distinct proteomic signatures and biological pathways associated with different PASC symptoms. An individual who reported PASC headache and drowsiness (n = 1) had elevated histones, prelamin A/C, lysozyme C and S100-A9, among other proteins enriched with cellular stress pathways, including DNA damage, oxidative/metabolic/cytoskeletal stress, senescence, neutrophil degranulation and neurodegenerative-like diseases. Conversely, some participants who reported pulmonary PASC (n = 5, pooled) had elevated histones but decreased fibrinogen, integrin β-3 and S100-A9, mapped to senescence, platelet dysfunction, and immune exhaustion pathways. Non-PASC individuals (n = 9) exhibited active inflammation resolution, without returning to the pre-infection homeostasis even after 6–8 months post-infection. These distinct PBMC-EV proteomic signatures suggest potential long-term impact of long COVID with implications for the public health and mission readiness of US service members.