Interindividual clinical variability in the course of SARS-CoV-2 infection is immense. We report that at least 101 of 987 patients with life-threatening COVID-19 pneumonia had neutralizing IgG auto-Abs against IFN-ω (13 patients), the 13 types of IFN-α (36), or both (52), at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1,227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 were men. A B cell auto-immune phenocopy of inborn errors of type I IFN immunity underlies life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men.

Clinical outcome upon infection with SARS-CoV-2 ranges from silent infection to lethal COVID-19. We have found an enrichment in rare variants predicted to be loss-of-function (LOF) at the 13 human loci known to govern TLR3- and IRF7-dependent type I interferon (IFN) immunity to influenza virus, in 659 patients with life-threatening COVID-19 pneumonia, relative to 534 subjects with asymptomatic or benign infection. By testing these and other rare variants at these 13 loci, we experimentally define LOF variants in 23 patients (3.5%), aged 17 to 77 years, underlying autosomal recessive or dominant deficiencies. We show that human fibroblasts with mutations affecting this pathway are vulnerable to SARS-CoV-2. Inborn errors of TLR3- and IRF7-dependent type I IFN immunity can underlie life-threatening COVID-19 pneumonia in patients with no prior severe infection.

Communicated by Andrew O.M. WilkieMutations in the inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase gamma (IKBKG), also called nuclear factor-kappaB (NF-kB) essential modulator (NEMO), gene are the most common single cause of incontinentia pigmenti (IP) in females and anhydrotic ectodermal dysplasia with immunodeficiency (EDA-ID) in males. The IKBKG gene, located in the Xq28 chromosomal region, encodes for the regulatory subunit of the inhibitor of kappaB (IkB) kinase (IKK) complex required for the activation of the NF-kB pathway. Therefore, the remarkably heterogeneous and often severe clinical presentation reported in IP is due to the pleiotropic role of this signaling transcription pathway. A recurrent exon 4_10 genomic rearrangement in the IKBKG gene accounts for 60 to 80% of IP-causing mutations. Besides the IKBKG rearrangement found in IP females (which is lethal in males), a total of 69 different small mutations (missense, frameshift, nonsense, and splice-site mutations) have been reported, including 13 novel ones in this work. The updated distribution of all the IP-and EDA-ID-causing mutations along the IKBKG gene highlights a secondary hotspot mutation in exon 10, which contains only 11% of the protein. Furthermore, familial inheritance analysis revealed an unexpectedly high incidence of sporadic cases (465%). The sum of the observations can aid both in determining the molecular basis of IP and EDA-ID allelic diseases, and in genetic counseling in affected families. Hum Mutat 29(5), [595][596][597][598][599][600][601][602][603][604] 2008.

Significance There is growing evidence that preexisting autoantibodies neutralizing type I interferons (IFNs) are strong determinants of life-threatening COVID-19 pneumonia. It is important to estimate their quantitative impact on COVID-19 mortality upon SARS-CoV-2 infection, by age and sex, as both the prevalence of these autoantibodies and the risk of COVID-19 death increase with age and are higher in men. Using an unvaccinated sample of 1,261 deceased patients and 34,159 individuals from the general population, we found that autoantibodies against type I IFNs strongly increased the SARS-CoV-2 infection fatality rate at all ages, in both men and women. Autoantibodies against type I IFNs are strong and common predictors of life-threatening COVID-19. Testing for these autoantibodies should be considered in the general population.