How our immune system is linked to the long Covid

American researchers have found that an abnormally suppressed immune system may be the cause of the long duration of Covid-19 and not the persistent overactive system previously thought. In a subset of people who recover from the initial Covid illness, various symptoms persist, such as fatigue, confusion and shortness of breath, which can be debilitating and last for months. This is generally classified as long Covid, although symptoms vary widely and this syndrome is unlikely to be a single disease entity. However, a limited understanding of its causes makes finding ways to treat the disease particularly difficult. Many scientists have suggested that the persistence of immune overactivity after Covid-19 is a major contributor. To explore, researchers at the University of California, Los Angeles conducted a small exploratory trial of Leronlimab — an antibody that binds to an immune receptor called CCR5 that’s involved in inflammation — on 55 people with the syndrome. underactive immune systems after recovering from Covid-19, which means boosting immunity in these individuals could be a treatment,” said Dr. Otto Yang, a professor at UCLA’s David Geffen School of Medicine. The study was published in the peer-reviewed journal Clinical Infectious Diseases.

Participants were randomly assigned to receive weekly injections of the antibody or a saline placebo for eight weeks, during which they tracked any changes in 24 symptoms associated with long Covid, which also included loss of smell and taste, muscle and joint pain and brain fog. Researchers originally thought that blocking CCR5 with the antibody would curb the activity of an overactive immune system after Covid-19 infection. “But we found the exact opposite,” Yang said. The patients who improved were those who started out with low CCR5 T cells, suggesting their immune system was less active than normal, and CCR5 levels actually increased in those who improved. This leads to the new hypothesis that long Covid in some people is related to the suppressed and non-overactive immune system, and that while blocking its activity, the antibody may stabilize the expression of CCR5 on the cell surface, resulting in a upregulation of other immune receptors or functions, Yang said. gs “suggests a complex role for CCR5 in balancing inflammatory and anti-inflammatory effects, for example via T-regulatory cells”, although the findings need to be confirmed in a larger, more definitive study.

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