title: Prolonged myalgia in Sindbis virus infection: case description and in vitro infection of myotubes and myoblasts.
abstract: BACKGROUND
  Sindbis virus (SINV) is a mosquito-borne alphavirus found in Eurasia, Africa, and Oceania. Clinical SINV infection is characterized by febrile rash and arthritis and sometimes prolonged arthralgia and myalgia. The pathophysiological mechanisms of musculoskeletal and rheumatic disease caused by SINV are inadequately understood.
  
  
  METHODS
  We studied the muscle pathology of SINV infection ex vivo by examining a unique muscle biopsy obtained from a patient with chronic myalgia and arthralgia 6 months after acute SINV infection and assessed potential genetic predisposing factors by determining the human leukocyte antigen (HLA) and complement factor C4 genes and proteins. In addition, we performed in vitro SINV infections of primary human myoblasts and myotubes.
  
  
  RESULTS
  In the muscle biopsy we found evidence of muscle regeneration due to previous necrotic lesions likely caused by earlier SINV infection. We showed that human myoblasts and myotubes were susceptible in vitro for SINV infection as the cells became immunoreactive for viral antigens and cytopathic effect was observed. The patient was homozygous for HLA-B*35 alleles and heterozygous for HLA-DRB1*01 and HLA-DRB1*03 alleles and had total deficiency of C4B protein.
  
  
  CONCLUSIONS
  This study provides new insights concerning pathological processes leading to chronic symptoms in SINV infection and demonstrates for the first time the susceptibility of human myogenic cells to SINV infection.
authors.affiliation: Infection Biology Research Program, Research Programs Unit, Department of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, Helsinki, Finland. jussi.sane@helsinki.fi
authors.forename: Jussi
authors.initials: J
authors.lastname: Sane
authors.forename: Satu
authors.initials: S
authors.lastname: Kurkela
authors.forename: Marion
authors.initials: M
authors.lastname: Desdouits
authors.forename: Hannu
authors.initials: H
authors.lastname: Kalimo
authors.forename: Simon
authors.initials: S
authors.lastname: Mazalrey
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Lokki
authors.forename: Antti
authors.initials: A
authors.lastname: Vaheri
authors.forename: Tapani
authors.initials: T
authors.lastname: Helve
authors.forename: Jyrki
authors.initials: J
authors.lastname: Törnwall
authors.forename: Michel
authors.initials: M
authors.lastname: Huerre
authors.forename: Gillian
authors.initials: G
authors.lastname: Butler-Browne
authors.forename: Pierre-Emmanuel
authors.initials: PE
authors.lastname: Ceccaldi
authors.forename: Antoine
authors.initials: A
authors.lastname: Gessain
authors.forename: Olli
authors.initials: O
authors.lastname: Vapalahti
mesh_terms: D018354:Alphavirus Infections / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000821:virology*; D009135:Muscular Diseases / Q000821:virology*; D032446:Myoblasts / Q000821:virology*; D010146:Pain / Q000150:complications* / Q000821:virology; D012367:RNA, Viral / Q000302:isolation & purification; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012845:Sindbis Virus
chemical_list: D012367:RNA, Viral