Long COVID Symptoms Linked to Autoantibodies

A new study published in Cell Reports Medicine provides some of the strongest evidence to date that antibodies may play a direct role in Long COVID symptoms. Researchers found that immunoglobulin G (IgG) antibodies taken from Long COVID patients caused persistent pain-like sensitivity when transferred into mice, suggesting these antibodies may actively contribute to the condition rather than simply reflect immune dysfunction.

Importantly, this effect was still observed when antibodies collected from the same patients two years later were tested, indicating that the underlying immune response may persist long after the initial infection. The study also identified distinct biological subgroups of patients, each with different immune markers and autoantibody patterns, supporting the idea that Long COVID is not a single condition but a collection of related syndromes with different underlying mechanisms.

These autoantibodies were found to target a wide range of the body’s own proteins, including those involved in nerve signaling, immune regulation, and metabolism. This may help explain the wide range of symptoms seen in Long COVID, such as pain, fatigue, and cognitive difficulties.

While further research is needed, the findings suggest that treatments aimed at removing or neutralizing harmful antibodies, such as plasmapheresis or targeted immunotherapy, could offer new options for some patients.

Citation

Chen, H. J., Appelman, B., Willemen, H. L. D. M., Bos, A., Prado, J., Mak, W. A., Keijzer, N., Santos Ribeiro, P. S., Goncalves, S. V., Versteeg, S., Geyer, C. E., Larsen, M., Schüchner, E., Bomers, M. K., Lavell, A. H. A., Amsterdam UMC COVID-19 biobank, Charlton, B., Wüst, R., Wiersinga, W. J., van Vugt, M., … den Dunnen, J. (2026). Transfer of IgG from long COVID patients induces symptomology in mice. Cell reports. Medicine, 102693. Advance online publication. https://doi.org/10.1016/j.xcrm.2026.102693