Long Covid and Auto-antibodies to INF9 Mar 2022 10:16
Published yesterday in Cell
https://www.cell.com/trends/immunology/fulltext/S1471-4906(22)00047-3
"The investigators also identified the presence of certain autoantibodies, including those targeting type I interferons (IFNs), that could predict PASC. Their observations suggest plausible mechanisms by which SARS-CoV-2 infection can cause persistent symptoms. For example, a higher degree of SARS-CoV-2 viremia likely reflects higher tissue viral burden and increased likelihood of end-organ damage. Higher viremia might also be associated with immunologic perturbations that could lead to organ dysfunction; some of these might persist beyond early convalescence. The relationships for other factors are less clear, for example, EBV viremia may more plausibly reflect the severity of initial illness rather than represent a causal mechanism of PASC, although the recent observation that EBV reactivation might lead to multiple sclerosis suggests this virus can contribute to autoimmune syndromes [2.]. Furthermore, the identification of a relationship with anti-IFN antibodies, previously shown to be important in acute COVID-19 [3.], suggests another mechanism that may tie together an impaired antiviral response, an enhanced inflammatory response, and generation of downstream autoimmune processes.
In a different analysis of several hundred individuals during acute infection and up to a year later [4.], Cervia and colleagues identified a distinct SARS-CoV-2 specific immunoglobulin signature during acute infection among those who went on to develop PASC. Specifically, they found that reduced IgM and IgG3 titers during acute infection were a risk factor for PASC, which the authors suggest might be related to reduced production of type I IFNs resulting in a failure of isotype switching. Using these laboratory measurements in combination with certain clinical factors (e.g., age, asthma history, number of acute COVID-19 symptoms), the team generated a prediction model to identify those who developed PASC [4.]."