subsets of Long COVID participants also had polyfunctional IL-4 / IL-6 co-expressing CD4+ T cells
which correlated with antibody reactivity against EBV lytic antigens, but not SARS-CoV-2 antigens. In
aggregate, these findings are consistent with chronic immune engagement against reservoirs of viral
antigen among participants with Long COVID."
"Most strikingly among participants with Long COVID,
levels of plasma cortisol were roughly half of those found in healthy or convalescent controls. Based on
machine learning, cortisol levels alone were the most significant predictor for Long COVID
classification, as well as for estimation of Long COVID Propensity Score. "
"Multiple hypotheses have been
proposed for Long COVID pathogenesis, including persistent virus/virus remnants, autoimmunity,
dysbiosis, latent viral reactivation and unrepaired tissue damage 18,32–38
. Our data suggest the involvement
of persistent antigen, reactivation of latent herpesviruses, and chronic inflammation, and are less
consistent with the autoantibodies to extracellular antigens."