title: Myositis in primary Sjögren's syndrome: data from a multicentre cohort.
abstract: OBJECTIVE
  In primary Sjögren's syndrome (pSS), muscle pain and/or muscular weakness is relatively frequent while myositis has been reported in 3% of patients. The aim of this study was to describe the prevalence of myositis in a multicentre Italian pSS cohort and to address the clinical manifestations, histological findings and therapeutic strategies.
  
  
  METHODS
  Clinical, serological and therapeutic data from a pSS cohort of patients were retrospectively collected. According to Bohan and Peter's criteria, inflammatory myopathy (IM) was suspected in case of muscular weakness associated with increased creatine-phosphokinase (CPK) or abnormal electromyography (EMG). When performed, muscle biopsies were analysed.
  
  
  RESULTS
  In a cohort of 1320 patients, 17 (1.28%) presented muscular weakness [in some cases myalgias (7/17, 41.1%)], accompanied by increased CPK [13/17, (76.4%)] and/or abnormal EMG [13/14, (92.8%)]. Ten out of 17 (58.8%) fulfilled at least three diagnostic criteria for IM. Muscular biopsy was performed in 13/17 (76.4%) cases with histologically confirmed myositis in 6/13 (46.1%) (1"IBM-like"-5"PM-like"). In two "PM-like" cases, several fibres showed a decreased histochemical cytochrome C oxidase (COX) stain. Two biopsies tested "negative", four showed "non-specific" findings. All patients were treated with corticosteroids followed by different DMARDs.
  
  
  CONCLUSIONS
  Our retrospective analysis shows a prevalence of myositis in pSS lower than previously reported, mainly appearing as an overlapping syndrome. Histological findings confirm the possible presence of an IBM or of a myopathy more similar to PM with a decreased COX activity. Classical immunosuppressants are effective although in most difficult cases IVIg or RTX may be used with benefit.
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Colafrancesco
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Priori
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Angelica
authors.initials: A
authors.lastname: Gattamelata
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Picarelli
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Antonina
authors.initials: A
authors.lastname: Minniti
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Brancatisano
authors.affiliation: Department of Radiological Sciences, Oncology ed Anatomo-Pathology, Sapienza University of Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: D'Amati
authors.affiliation: Department of Radiological Sciences, Oncology ed Anatomo-Pathology, Sapienza University of Rome, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Giordano
authors.affiliation: Department of Radiological Sciences, Oncology ed Anatomo-Pathology, Sapienza University of Rome, Italy.
authors.forename: Bruna
authors.initials: B
authors.lastname: Cerbelli
authors.affiliation: Rheumatology Clinic, DSMB, University of Udine, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Maset
authors.affiliation: Rheumatology Clinic, DSMB, University of Udine, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Quartuccio
authors.affiliation: Rheumatology Unit, Department of Clinical and Experimental Medicine, University of Perugia, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Bartoloni
authors.affiliation: Rheumatology Clinic, University of L'Aquila, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Carubbi
authors.affiliation: Rheumatology Clinic, University of L'Aquila, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Cipriani
authors.affiliation: Rheumatology Unit, University of Pisa, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Baldini
authors.affiliation: Rheumatology Unit, University of Pisa, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Luciano
authors.affiliation: Rheumatology Clinic, DSMB, University of Udine, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: De Vita
authors.affiliation: Rheumatology Unit, Department of Clinical and Experimental Medicine, University of Perugia, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Gerli
authors.affiliation: Rheumatology Clinic, University of L'Aquila, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Giacomelli
authors.affiliation: Rheumatology Unit, University of Pisa, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bombardieri
authors.affiliation: Department of Internal Medicine and Medical Specialties, Rheumatology Unit, Sapienza University of Rome, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Valesini
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001323:Autoantibodies / Q000097:blood; D001706:Biopsy; D003402:Creatine Kinase / Q000097:blood; D004576:Electromyography / Q000379:methods; D003576:Electron Transport Complex IV / Q000032:analysis; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis; D018482:Muscle, Skeletal / Q000473:pathology*; D009220:Myositis / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D015995:Prevalence; D012189:Retrospective Studies; D012859:Sjogren's Syndrome / Q000150:complications*
chemical_list: D018501:Antirheumatic Agents; D001323:Autoantibodies; D005938:Glucocorticoids; D003576:Electron Transport Complex IV; D003402:Creatine Kinase