Autoimmunity Drives Long COVID Symptoms - Neuroscience News
Purifying and transferring circulating autoantibodies from human long COVID patients into healthy mouse models replicates the physical symptom burden of the chronic condition. Credit: Neuroscience News<br>Autoimmunity Drives Long COVID Symptoms
FeaturedNeurologyNeuroscience<br>·May 28, 2026
Summary: New findings reveal autoimmunity is the primary biological driver behind the confounding and often-debilitating symptoms of long COVID in a distinct subset of patients. The study demonstrated a direct causal link by purifying antibodies from the blood of human long COVID patients and infusing them into healthy mice, yielding striking physical and physiological results.<br>This major neuro-immune validation opens the door to using targeted, already-validated autoimmune therapies, such as IVIG, FcRn inhibitors, plasmapheresis, and advanced CAR-T cell therapy, to systematically reduce the chronic symptom burden for millions of individuals.<br>Key Facts<br>The Long COVID Burden : Between 4% and 20% of individuals infected with COVID-19 go on to develop long COVID, enduring persistent fatigue, cognitive impairment ("brain fog"), heart palpitations, and severe joint and muscle pain for months or years. The underlying pathology involves viral persistence, latent virus reactivation (such as herpesviruses), and a damaged, un-reset immune system trapped in chronic inflammation.<br>The Human-to-Mouse Transfer Proof : To isolate the exact role of the immune system, researchers collected and purified antibodies from the blood of 87 human participants diagnosed with long COVID and infused them directly into healthy laboratory mice, establishing an unmistakable biological trigger for the condition’s physical symptoms.<br>A Quantifiable Screening Tool : Prior to this study, clinicians had no way of predicting which long COVID patients would respond to specialized immunotherapies. The findings prove that the presence of circulating autoantibodies acts as a clear, quantifiable biomarker indicating which patients are optimal candidates for antibody-lowering drugs.<br>Repurposing the Autoimmune Arsenal : Validating this autoimmune physiology allows scientists to confidently deploy existing, highly sophisticated immune-regulating treatments. These include Intravenous Immunoglobulin (IVIG) to balance the immune response, FcRn inhibitors to lower overall antibody counts, Plasmapheresis to physically filter autoantibodies out of the blood, and CAR-T cell therapy to genetically program a patient’s T cells to hunt down and destroy the cells secreting harmful autoantibodies.<br>Overcoming Industry Hesitancy : Clinical trials for treatments like IVIG have previously yielded highly inconsistent real-world results, with some long COVID patients recovering completely while others saw no change, which severely dampened pharmaceutical industry enthusiasm. This study resolves the mystery: the drugs only work if the patient belongs to the specific autoimmune subtype, allowing for precision-targeted clinical trials.<br>An Urgent Public Health Warning : Senior author Dr. David Putrino issues a stark warning regarding global blood supply safety. While individuals with long COVID are strictly excluded from donating blood in the United Kingdom, the United States still permits them to donate, posing a hidden public health threat to blood and plasma recipients that demands immediate policy updates.<br>Source: Mount Sinai Hospital<br>A Mount Sinai-led research team has demonstrated that autoimmunity, where the body’s immune system attacks its own tissues, is responsible for the often-debilitating and confounding symptoms of long COVID in a subset of people.<br>Findings from the study, published in Cell on May 28, could lead to important new approaches to treating patients with long COVID, including already-validated therapies for management of autoimmunity as well as new ways of clinically identifying which patients are most likely to benefit from these therapies.<br>“We’ve known for some time that long COVID involves not just one but a variety of phenotypes, and now we have validated that autoimmunity is a major contributor to the symptom burden,” says David Putrino, PhD, Nash Family Director of the Cohen Center for Recovery From Complex Chronic Illness at Mount Sinai and co-senior author of the study. “This new awareness of the physiology of long COVID will enable us to identify a number of effective treatments for autoimmunity that could significantly improve the symptoms of millions of people with this chronic condition.”<br>Studies have shown that between 4 and 20 percent of people infected with COVID-19 continue to experience symptoms such as persistent fatigue, cognitive impairment, heart palpitations, and joint and muscle pain for months or even years. Mechanisms behind this prolonged form of the disease are believed to include viral persistence, reactivation of previously latent viruses such as herpesviruses, and immune...