Potential immunological triggers for narcolepsy and idiopathic hypersomnia: Real-world insights on infections and influenza vaccinations.

Objective: It is hypothesized that narcolepsy type 1 (NT1) develops in genetically susceptible people who encounter environmental triggers leading to immune-mediated hypocretin-1 deficiency. The pathophysiologies of narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) remain unknown. The main aim of this study was to collect all reported immunological events before onset of a central disorder of hypersomnolence.
Methods: Medical records of 290 people with NT1, and 115 with NT2 or IH were retrospectively reviewed to extract infection and influenza vaccination history. Prevalence, distribution of immunological events, and time until hypersomnolence onset were compared between NT1 and the combined group of NT2 and IH.
Results: Immunological events were frequently reported before hypersomnolence disorder onset across groups. Flu and H1N1 influenza vaccination were more common in NT1, and Epstein-Barr virus and other respiratory and non-respiratory infections in NT2 and IH. Distributions of events were comparable between NT2 and IH. Rapid symptom onset within one month of infection was frequent across groups, especially after flu infection in NT1. Hypersomnolence disorder progression after an immunological event was reported in ten individuals.
Conclusions: Our findings suggest a variety of immunological triggers potentially related to NT1, including H1N1 influenza infection or vaccination, infection with other flu types, and other respiratory and non-respiratory infections. Frequent reports of immunological events (other than those reported in NT1) immediately prior to the development of NT2 and IH support the specificity of triggers for NT1, and open important new research avenues into possible underlying immunological mechanisms in NT2 and IH.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lammers GJ reports a relationship with Alkermes plc that includes: consulting or advisory. Lammers GJ reports a relationship with Takeda Pharmaceutical Company Limited that includes: consulting or advisory. Lammers GJ reports a relationship with Bioprojet that includes: consulting or advisory. Lammers GJ reports a relationship with Jazz Pharmaceuticals plc that includes: consulting or advisory. Fronczek R reports a relationship with Takeda Pharmaceutical Company Limited that includes: consulting or advisory. Fronczek R reports a relationship with Bioprojet that includes: consulting or advisory, funding grants, and speaking and lecture fees. Fronczek R reports a relationship with Jazz Pharmaceuticals plc that includes: funding grants. Khatami R reports a relationship with Neuraxpharm that includes: consulting or advisory. Khatami R reports a relationship with Idorsia Pharmaceuticals Ltd that includes: consulting or advisory. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)