Autoantibodies neutralizing type I IFNs underlie West Nile virus encephalitis in ∼40% of patients.

"Disclosures: Q. Philippot reported grants from Assistance Publique Hopitaux de Paris, Fondation Bettencourt Schueller, ARS Ile de France, and personal fees from Gilead outside the submitted work. M.S. Diamond reported personal fees from Topspin Therapeutics outside the submitted work. J.-L. Casanova reported a patent to PCT/US2021/042741 pending. No other disclosures were reported."

"The Laboratory of Human Genetics of Infectious Diseases is supported by the Howard Hughes Medical Institute, The Rockefeller University, the St. Giles Foundation, the National Institutes of Health (NIH; grants R01AI088364, R01AI127564, R01AI163029, and R21AI160576), the National Center for Advancing Translational Sciences (NCATS), the NIH Clinical and Translational Science Award (CTSA) program (UL1TR001866), the Fisher Center for Alzheimer’s Research Foundation, the Meyer Foundation, the JPB Foundation, the “Investissement d’Avenir” program launched by the French Government and implemented by the Agence Nationale de la Recherche (ANR; grant ANR-10-IAHU-01), the Integrative Biology of Emerging Infectious Diseases Laboratory of Excellence (grant ANR-10-LABX-62-IBEID), the French Foundation for Medical Research (FRM; grant EQU201903007798), ANR GENVIR (ANR-20-CE93-003), ANR AI2D (ANR-22-CE15-0046), and ANR AAILC (ANR-21-LIBA-0002) projects, the HORIZON-HLTH-2021-DISEASE-04 program under grant agreement 01057100 (UNDINE), the ANR-RHU COVIFERON Program (ANR-21-RHUS-08), the Square Foundation, Grandir - Fonds de solidarité pour l’enfance, the Fondation du Souffle, the SCOR Corporate Foundation for Science, the Battersea & Bowery Advisory Group, The French Ministry of Higher Education, Research, and Innovation (MESRI-COVID-19), INSERM, REACTing-INSERM, and the University of Paris. J. Rosain, P. Bastard and T. Le Voyer were supported by the MD-PhD program of the Imagine Institute (with support from the Bettencourt-Schueller Foundation). J. Rosain was supported by a “Poste d’accueil Inserm”. P. Bastard was supported by a “Poste CCA-INSERM-Bettencourt” (with support from the Bettencourt-Schueller Foundation) and the FRM (grant EA20170638020). Q. Philippot was supported by the Assistance Publique Hôpitaux de Paris (Année Recherche) and is supported by the MD-PhD program of INSERM (Ecole de l’INSERM Liliane Bettencourt). M.P. Lorenzo was supported by the European Society for Immunodeficiencies (ESID), KvK 40448576. The Borghesi group, Fondazione IRCCS Policlinico San Matteo is supported by grants from the Italian Ministry of Health, RC08061819 and RC08061822, and by 5X1000 grant 08061821 from the San Matteo Hospital. The Diamond laboratory is supported by NIH grants R01AI073755 and R01DK122790. The Murray laboratory is supported by NIH grants R01AI091816 and U19AI089992. The Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia and the Department of Molecular Medicine, University of Padova are supported by EU funding within the Next-Generation EU-MUR PNRR Extended Partnership initiative on Emerging Infectious Diseases (project no. PE00000007, INF-ACT). The Microbiology and Virology Unit, Fondazione IRCCS Policlinico San Matteo is supported by funding from the Ministry of Health, RC80206. The Department of Molecular Medicine, University of Padova is supported by the European Union’s Horizon 2020 research and innovation program (VEO, grant agreement 874735) and the EU4Health program (DURABLE, grant agreement101102733). The Laboratory of Virology and Infectious Disease (M.R. MacDonald and C.M. Rice) is supported by NIH grants R01AI124690 and R01AI091707. Open Access funding provided by Rockefeller University. Disclosures: Q. Philippot reported grants from Assistance Publique Hopitaux de Paris, Fondation Bettencourt Schueller, ARS Ile de France, and personal fees from Gilead outside the submitted work. M.S. Diamond reported personal fees from Topspin Therapeutics outside the submitted work. J.-L. Casanova reported a patent to PCT/US2021/042741 pending. No other disclosures were reported."