Researchers from the Translational Genomics Research Institute (TGen) and the Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center have reported findings that could lead to the identification of a biomarker for long COVID. This potential biomarker might serve as a specific and quantifiable indicator for diagnosing long COVID, moving beyond the current reliance on symptom-based assessments made by healthcare providers.
The study, published in the journal Infection, focused on the detection of SARS-CoV-2 protein fragments within extracellular vesicles (EVs) found in the blood of long COVID patients. The research involved blood samples from 14 patients, collected over 12 weeks during a clinical trial exploring the effects of aerobic exercise on long COVID symptoms. The team identified 65 distinct protein fragments derived from the virus's Pp1ab protein, which is integral to the virus's replication process and is not present in uninfected human cells.
Notably, these protein fragments were consistently found in the EVs of long COVID patients but were absent in a control group of pre-pandemic samples. This suggests the possibility of persistent viral remnants in the body long after the initial infection. However, questions remain regarding how the virus might reach various tissues without typical entry points, such as the brain.
While the findings are promising, researchers caution that the molecular signals from the viral peptides were subtle and not consistently detected across all blood samples. Future research is needed to determine whether these viral fragments are remnants of previous infections or indicative of ongoing viral activity. The study was funded by the Pulmonary Education and Research Foundation and the UCLA David Geffen School of Medicine-Ventura County Community Foundation.