Unlocking life-threatening COVID-19 through two types of inborn errors of type I IFNs

Abstract

Since 2003, rare inborn errors of human type I IFN immunity have been discovered, each underlying a few severe viral illnesses. Autoantibodies neutralizing type I IFNs due to rare inborn errors of autoimmune regulator (AIRE)-driven T cell tolerance were discovered in 2006, but not initially linked to any viral disease. These two lines of clinical investigation converged in 2020, with the discovery that inherited and/or autoimmune deficiencies of type I IFN immunity accounted for approximately 15%-20% of cases of critical COVID-19 pneumonia in unvaccinated individuals. Thus, insufficient type I IFN immunity at the onset of SARS-CoV-2 infection may be a general determinant of life-threatening COVID-19. These findings illustrate the unpredictable, but considerable, contribution of the study of rare human genetic diseases to basic biology and public health.

Figure 1. Inborn errors of type I IFN immunity or tolerance.

Left, middle: Variants in genes expressed in thymic medullary epithelial cells, indicated in red, are linked to a defect in T cell selection and the production of type I IFN autoantibodies. Right: Variants in genes indicated in red alter type I IFN induction and response pathways.