title: Brief Report: Association of Myositis Autoantibodies, Clinical Features, and Environmental Exposures at Illness Onset With Disease Course in Juvenile Myositis.
abstract: OBJECTIVE
  To identify early factors associated with disease course in patients with juvenile idiopathic inflammatory myopathies (IIMs).
  
  
  METHODS
  Univariable and multivariable multinomial logistic regression analyses were performed in a large juvenile IIM registry (n = 365) and included demographic characteristics, early clinical features, serum muscle enzyme levels, myositis autoantibodies, environmental exposures, and immunogenetic polymorphisms.
  
  
  RESULTS
  Multivariable associations with chronic or polycyclic courses compared to a monocyclic course included myositis-specific autoantibodies (multinomial odds ratio [OR] 4.2 and 2.8, respectively), myositis-associated autoantibodies (multinomial OR 4.8 and 3.5), and a documented infection within 6 months of illness onset (multinomial OR 2.5 and 4.7). A higher overall clinical symptom score at diagnosis was associated with chronic or monocyclic courses compared to a polycyclic course. Furthermore, severe illness onset was associated with a chronic course compared to monocyclic or polycyclic courses (multinomial OR 2.1 and 2.6, respectively), while anti-p155/140 autoantibodies were associated with chronic or polycyclic courses compared to a monocyclic course (multinomial OR 3.9 and 2.3, respectively). Additional univariable associations of a chronic course compared to a monocyclic course included photosensitivity, V-sign or shawl sign rashes, and cuticular overgrowth (OR 2.2-3.2). The mean ultraviolet index and highest ultraviolet index in the month before diagnosis were associated with a chronic course compared to a polycyclic course in boys (OR 1.5 and 1.3), while residing in the Northwest was less frequently associated with a chronic course (OR 0.2).
  
  
  CONCLUSIONS
  Our findings indicate that myositis autoantibodies, in particular anti-p155/140, and a number of early clinical features and environmental exposures are associated with a chronic course in patients with juvenile IIM. These findings suggest that early factors, which are associated with poorer outcomes in juvenile IIM, can be identified.
authors.affiliation: University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: G Esther A
authors.initials: GE
authors.lastname: Habers
authors.affiliation: IWK Health Center and Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Huber
authors.affiliation: George Washington University School of Medicine, Washington, DC.
authors.forename: Gulnara
authors.initials: G
authors.lastname: Mamyrova
authors.affiliation: VAMC, University of Oklahoma Health Sciences Center, and Oklahoma Medical Research Foundation, Oklahoma City.
authors.forename: Ira N
authors.initials: IN
authors.lastname: Targoff
authors.affiliation: National Institute of Environmental Health Sciences, NIH, Bethesda, MD.
authors.forename: Terrance P
authors.initials: TP
authors.lastname: O'Hanlon
authors.affiliation: NIH Clinical Center, Bethesda, MD.
authors.forename: Sharon
authors.initials: S
authors.lastname: Adams
authors.affiliation: Medical University of South Carolina, Charleston.
authors.forename: Janardan P
authors.initials: JP
authors.lastname: Pandey
authors.affiliation: University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Chantal
authors.initials: C
authors.lastname: Boonacker
authors.affiliation: University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marco
authors.initials: M
authors.lastname: van Brussel
authors.affiliation: National Institute of Environmental Health Sciences, NIH, Bethesda, MD.
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Miller
authors.affiliation: University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Annet
authors.initials: A
authors.lastname: van Royen-Kerkhof
authors.affiliation: National Institute of Environmental Health Sciences, NIH, Bethesda, MD.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Rider
mesh_terms: D001323:Autoantibodies / Q000032:analysis; D002648:Child; D002908:Chronic Disease; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009220:Myositis / Q000235:genetics / Q000276:immunology / Q000503:physiopathology*; D011110:Polymorphism, Genetic; D012042:Registries
chemical_list: D001323:Autoantibodies