Are Rogue Antibodies Behind Long COVID?

Antibodies isolated from patients with Long COVID triggered similar symptoms in mice, new study shows

For the 10-20% of people suffering from Long COVID, the epidemic has never really ended. Their days are filled with debilitating fatigue, brain fog and chronic pain. There are a number of competing theories about what might be driving this condition, including the presence of autoantibodies -- rogue antibodies that people make that rise up and attack their immune system and tissue. 

Now, a new Dutch study provides compelling evidence that these rogue proteins could indeed be the culprit. The researchers collected IgG antibodies, the most common type of antibody in human bodily fluids, from 34 individuals who developed Long COVID after mild cases of SARS-CoV-2. Most of the participants experienced fatigue and chronic pain and couldn't work. 

The researchers assigned participants to groups based on the concentrations of various inflammatory proteins in their blood, and pooled antibodies from members of each group. Then they injected each mouse with one of the pools. 

The researchers find that various antibody groups had distinct effects on pain perception and motor activity in the mice. Large studies will need to be done to see if the findings can be replicated, but if the evidence holds it could open the door to treatments for Long COVID.

To learn more about this study, check out the story in Nature's News and Comment section.