Science.org has an article covering some recent research into blood taken from people Long COVID. The research looked in depth at T-cells and the immune response and also noted that the symptoms they were seeing in the this group were similar to those with ME/CFS.
Extracts
The new study was modest in size, examining just 99 people with Long Covid.
The Long Covid patients, most of them struggling with intense fatigue, brain fog, and other symptoms, had low levels of cortisol, a stress hormone that helps the body control inflammation, glucose, sleep cycles, and more. Features of their T cells indicated their immune system was battling unidentified invaders, perhaps a reservoir of SARS-CoV-2 or a reactivated pathogen such as Epstein-Barr virus.
The Long Covid blood samples were also awash with a category of “exhausted” T cells that can be recognized by certain markers they express. Such cells surge in the ongoing presence of pathogens—suggesting “the bodies of people with Long Covid are actively fighting something,” David Putrino, a neurophysiologist at the Icahn School of Medicine at Mount Sinai, says.
This battle would produce chronic inflammation, which matches many Long Covid symptoms. By measuring levels of antibodies against viral proteins released in the blood, the study also noted reactivation of Epstein-Barr virus and other herpesviruses whose genes can sit dormant inside infected cells for extended periods. Iwasaki was intrigued to learn that degree of T cell exhaustion appeared to track with Epstein-Barr virus reactivation, though she doesn’t consider that virus the only potential culprit. SARS-CoV-2 may linger in Long Covid patients, too, she and others say. Epstein-Barr reactivation, low cortisol, and T cell exhaustion have all turned up in some ME/CFS patients.