Autoimmunity as a cause of Long COVID and ME/CFS

Prof Jeroen den Dunnen spoke about the effects of transferring immunoglobulin (IgG) autoantibodies from ME/CFS patients to mice. These antibodies are directed against a variety of epitopes that are predominantly found in the central nervous system, the peripheral nervous system, or the muscles. When autoantibodies from serum of different subgroups of ME/CFS patients are injected into mice, these mice display symptoms that correspond to the ME/CFS or Long COVID symptoms of the donors. When the mice received serum from patients with markers of muscle damage, they walked more slowly and less far. When they received serum from patients with markers of nerve cell damage, their pain sensitivity increased. These findings support the hypothesis that ME/CFS and Long COVID symptoms in subgroups of patients can be attributed to an autoimmune reaction. This opens up further avenues for therapeutic research (e.g. on immunoadsorption). The next research goals are: 1) Establishment of in vivo mouse models for Long COVID and ME/CFS by injecting autoantibodies derived from human B cells, 2) Establishment of an in vitro model in which muscle, heart, and nerve cells are cultured to be used for drug screening, and 3) Development of a diagnostic test for Long COVID and ME/CFS based on serum cytokine profiles. In addition, three randomised controlled trials (RCTs) are to take place in Amsterdam: 1) immunoadsorption based on antibody profiles, 2) drug trial with sonlicromanol, 3) drug trial with IDO-2 inhibitors.