Impact of immunoadsorption on autoantibodies and physical performance in post-COVID patients: a prospective exploratory study of 18 participants.

PURPOSE: Autoantibodies against β-adrenergic and muscarinic acetylcholine receptors are said to play a role in the pathophysiology of post-COVID syndrome. To date, only a limited number of studies have investigated the effectiveness of immunoadsorption. This prospective exploratory study investigates the effectiveness of immunoadsorption by assessing reductions in autoantibody levels and improvements in physical performance. METHODS: In a prospective exploratory clinical trial, 18 patients with post-COVID syndrome and elevated levels of antibodies against β1/β2-adrenergic receptors and/or M3/M4-muscarinic acetylcholine receptors were treated with a course of five consecutive immunoadsorption sessions. Clinical assessments, objective functional performance tests (e.g., step counters), laboratory parameters, and self-reported performance were performed during the study. RESULTS: A total of 15 women and 3 men were included in the study. Immunoadsorption was well tolerated. All participants showed a significant reduction in circulating antibodies against β1/β2-adrenergic receptors and M3/M4-muscarinic acetylcholine receptors; however, these levels returned to baseline within the following 3 to 6 months. Objective determinations of physical performance showed no significant improvement following immunoadsorption. Self-reported evaluation revealed a slight improvement in pain and fatigue. However, the correlation analysis failed to demonstrate a significant association between changes in autoantibody levels and subjectively perceived symptoms. CONCLUSION: Immunoadsorption was safe and resulted in a short-term, significant reduction in measured autoantibodies. However, there were no improvements in objectively measured performance. Our results indicate that immunoadsorption is not an effective approach for patients with post-COVID syndrome.