Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID?
Ruiz-Pablos, Manuel, Paiva, Bruno, Zabaleta, Aintzane · Journal of translational medicine · 2023 · DOI
Quick Summary
This study proposes that a virus called Epstein-Barr virus (EBV) may play a central role in both ME/CFS and long COVID by gradually weakening the immune system. The researchers suggest that in people with certain genetic traits, EBV can hide in various body tissues and repeatedly reactivate, causing ongoing inflammation and exhaustion of the immune system. They hypothesize that long COVID may follow a similar pattern, possibly starting with a COVID-19 infection in people whose immune systems struggle to control EBV.
Why It Matters
This study is important because it offers a unifying immunological explanation for why ME/CFS and long COVID share so many characteristics, potentially opening new avenues for treatment targeting EBV control and immune recovery. If the proposed mechanism is validated, it could lead to diagnostic tests based on immune markers and therapeutic interventions that benefit both patient populations. Understanding the role of EBV in disease persistence may also explain why some patients develop chronic illness after viral infections while others recover completely.
Observed Findings
ME/CFS and long COVID share similar immunological alterations including chronic inflammation, viral reactivation, autoimmunity, hypocortisolism, and microclot formation.
Both conditions present with overlapping symptoms: asthenia (extreme fatigue), exercise intolerance, sleep disorders, cognitive dysfunction, and neurological and gastrointestinal complaints.
EBV reactivation is present in both ME/CFS and long COVID patient populations.
Inferred Conclusions
Latent and recurrent EBV reactivation may generate an acquired immunodeficiency through a three-step process: initial EBV immunodeficiency in genetically susceptible individuals, formation of ectopic lymphoid structures with persistent EBV, and eventual immune exhaustion from chronic viral antigen exposure.
Long COVID may follow a similar immunopathological pathway, potentially triggered by prior SARS-CoV-2 infection in individuals with genetic susceptibility to both viruses.
EBV may be a pathogenic link connecting ME/CFS and long COVID through shared mechanisms of viral persistence and immune dysfunction.
Remaining Questions
Do individuals with ME/CFS and long COVID actually have 'weak' HLA-II haplotypes against EBV and/or SARS-CoV-2, and can this be validated in prospective genetic studies?
Where specifically do ectopic lymphoid structures form in ME/CFS and long COVID patients, and can they be detected through imaging or tissue sampling?
What This Study Does Not Prove
This study does not prove that EBV actually causes ME/CFS or long COVID, as it is a theoretical model based on literature review rather than direct experimental evidence. It does not demonstrate that 'weak' HLA-II haplotypes are the actual genetic factor responsible, nor does it establish causation versus correlation in the observed immunological similarities between the two conditions. The hypothesis remains to be tested through prospective studies comparing immune function and genetic markers in affected versus unaffected individuals.