title: Seropositivity for NT5c1A antibody in sporadic inclusion body myositis predicts more severe motor, bulbar and respiratory involvement.
abstract: OBJECTIVE
  To explore phenotypic differences between individuals with sporadic inclusion body myositis (sIBM) who are seropositive for the NT5c1A antibody compared with those who are seronegative.
  
  
  METHODS
  Cross-sectional clinical, serological and functional analysis in 25 consecutive participants with sIBM.
  
  
  RESULTS
  All participants met criteria for clinically defined or probable sIBM. 18 of 25 participants with sIBM (72%) were seropositive for the NT5c1A antibody. No differences between median age and duration of illness between the two groups were seen. Females have higher odds of being seropositive (OR=2.30). Participants with seropositive sIBM took significantly longer to get up and stand (p=0.012). There were no significant differences between the two groups in terms of distance covered on a 6 min walk. Seropositive participants were more likely to require assistive devices such as a walker or wheelchair for mobility (OR=23.00; p=0.007). A number of secondary (exploratory) outcomes were assessed. NT5c1A seropositive sIBM cases had lower total Medical Research Council (MRC) sum score and MRC sum score on the right (p=0.03 and 0.02, respectively). Participants with the NT5c1A antibody were significantly more likely to have symptoms of dysphagia (OR=10.67; p=0.03) and reduced forced vital capacity (p=0.005). Facial weakness occurred in 50% of seropositive participants while it was only seen in 14% of seronegative participants.
  
  
  CONCLUSIONS
  Even though the small sample size limits definite conclusions, our cross-sectional study showed seropositivity to the NT5c1A antibody is associated with greater motor and functional disability in sIBM. The study also suggests more prominent bulbar, facial and respiratory involvement in individuals positive for NT5c1A antibodies.
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: N A
authors: NA
authors: Goyal
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: T M
authors: TM
authors: Cash
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: U
authors: U
authors: Alam
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: S
authors: S
authors: Enam
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: P
authors: P
authors: Tierney
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: N
authors: N
authors: Araujo
authors: Department of Neurology, University of California, Irvine, California, USA.
authors: F H
authors: FH
authors: Mozaffar
authors: Department of Neurology, Washington University, St. Louis, Missouri, USA Department of Pathology, Washington University, St. Louis, Missouri, USA.
authors: A
authors: A
authors: Pestronk
authors: Department of Neurology, University of California, Irvine, California, USA Department of Orthopaedic Surgery, University of California, Irvine, California, USA.
authors: T
authors: T
authors: Mozaffar
mesh_terms: D015720:5'-Nucleotidase / Q000032:analysis / Q000276:immunology*; D000368:Aged; D000906:Antibodies / Q000032:analysis; D003430:Cross-Sectional Studies; D003680:Deglutition Disorders / Q000453:epidemiology / Q000209:etiology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D018979:Myositis, Inclusion Body / Q000150:complications* / Q000276:immunology* / Q000503:physiopathology; D011597:Psychomotor Performance; D011788:Quality of Life; D012120:Respiration Disorders / Q000209:etiology / Q000503:physiopathology; D012656:Self-Help Devices; D013118:Spinal Cord Diseases / Q000209:etiology / Q000503:physiopathology; D016896:Treatment Outcome; D014797:Vital Capacity
chemical_list: D000906:Antibodies; D015720:5'-Nucleotidase; C552626:NT5C1A protein, human
keywords: INCL BODY MYOSITIS; MUSCLE DISEASE; MYOPATHY; RESPIRATORY MEDICINE; SWALLOWING