We therefore established assays to screen for IgM and IgG autoantibodies against ACE2 and applied these initially to a cohort of 66 hospitalized patients with COVID-19 who reached the 6 most severe WHO ordinal groups as their maximal severity (28 severe, 38 moderate) (see Figure 1 for a flow diagram summarizing the cohorts studied and findings and Methods for more details about the WHO groups). This evidence concerns the gene CD40LG and COVID-19.