Autoantibodies neutralizing the antiviral action of type I interferons (IFNs) have been associated with pre-disposition to severe COVID-19. Here, we screened for such autoantibodies in 103 critically-ill COVID-19 patients in a tertiary intensive care unit in Switzerland. Eleven patients (10.7%), but no healthy donors, had neutralizing anti-IFN or anti-IFN/anti-IFN{omega} IgG in plasma/serum, but anti-IFN IgM or IgA was rare. One patient had non-neutralizing anti-IFN IgG. Strikingly, all patients with plasma anti-IFN IgG also had anti-IFN IgG in tracheobronchial secretions, identifying these autoantibodies at anatomical sites relevant for SARS-CoV-2 infection. Longitudinal analyses revealed patient heterogeneity in terms of increasing, decreasing, or stable anti-IFN IgG levels throughout the length of hospitalization. Notably, presence of anti-IFN autoantibodies in this critically-ill COVID-19 cohort appeared to predict herpesvirus (herpes simplex viruses types 1 and 2, HSV-1/-2; and/or cytomegalovirus, CMV) reactivations, which are linked to worse clinical outcomes. Indeed, all seven tested COVID-19 patients with anti-IFN IgG in our cohort (100%) suffered from one or more herpesvirus reactivations, and analysis revealed that these patients were substantially more likely to experience CMV reactivation than COVID-19 patients without anti-IFN autoantibodies, even when adjusting for systemic steroid treatment (odds ratio 7.28, 95%-CI 1.14-46.31, p=0.036). As the IFN system deficiency caused by neutralizing anti-IFN autoantibodies likely directly and indirectly exacerbates herpesvirus reactivations in critically-ill patients, early diagnosis of anti-IFN IgG could be rapidly used to inform risk-group stratification and treatment options.
Herpesvirus Reactivations in Critically-Ill COVID-19 Patients with Autoantibodies Neutralizing Type I Interferons