Antibodies against influenza A/H1N1pdm2009 and B/Victoria strains but not A/H3N2 are increased in recent onset type 1 narcolepsy versus matched controls

The study examined whether specific influenza strains can trigger narcolepsy type 1 (NT1) by measuring strain-specific antibodies. The research included 62 patients with recent NT1 onset and 100 matched controls by age, sex, and sample collection period. Patients with NT1 had elevated antibodies against A/H1N1pdm2009 and B/Victoria strains, but not against A/H1N1 pre-2009, A/H3N2, or B/Yamagata. This pattern was independent of HLA-DQB106:02 status, age, and sex. Antibodies against A/H1N1pdm2009 and B/Victoria were the strongest independent predictors of narcolepsy. The results suggest that only these two influenza strains, not others, can trigger the autoimmune process leading to loss of orexin-producing cells in the brain.