title: Increased plasma level of tumor necrosis factor α in patients with narcolepsy in Taiwan.
abstract: BACKGROUND
  Narcolepsy is a neuropsychiatric disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and abnormal rapid eye movement (REM) sleep. Tumor necrosis factor α (TNF α) and its cognate receptors have been reported to be involved in the pathophysiology of narcolepsy in addition to the HLA antigen system. Our study aimed to determine if the TNF-α system was associated with narcolepsy in our patients.
  
  
  METHODS
  We first measured the plasma level of TNF α in 56 narcoleptic patients and 53 control subjects using a highly sensitive enzyme-linked immunosorbent assay. We next determined the genotype of three single nucleotide polymorphisms (SNPs) (T-1031C, C-863A, and C-857T) at the promoter region of the TNF-α gene and one missense SNP (T587G, M196R) at the exon 6 of the tumor necrosis factor receptor 2 gene, TNFR2, in a sample of 75 narcoleptic patients and 201 control subjects by direct sequencing analysis.
  
  
  RESULTS
  We found a significant elevation of plasma level of TNF α in patients with narcolepsy compared with the control subjects (4.64pg/mL vs 1.06pg/mL; P=.0013). However, we did not find significant differences between these two groups in the allelic and genotypic distributions of the investigated polymorphisms.
  
  
  CONCLUSIONS
  Our study suggests that an increased TNF-α level was associated with narcolepsy in our patients, and that chronic inflammation due to various factors might have led to the increased TNF-α levels found in our patients.
authors.affiliation: Center for Neuropsychiatric Research, National Health Research Institutes, Zhunan, Taiwan.
authors.forename: Yun-Hsiang
authors.initials: YH
authors.lastname: Chen
authors.forename: Yu-Shu
authors.initials: YS
authors.lastname: Huang
authors.forename: Chia-Hsiang
authors.initials: CH
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D002385:Cataplexy / Q000235:genetics / Q000378:metabolism; D002648:Child; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense / Q000235:genetics; D009290:Narcolepsy / Q000235:genetics* / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000235:genetics; D013624:Taiwan; D014409:Tumor Necrosis Factor-alpha / Q000097:blood* / Q000235:genetics*; D055815:Young Adult
chemical_list: D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha
keywords: Association; Cataplexy; Inflammation; Narcolepsy; Pathogenesis; Tumor necrosis factor α