title: Anti-polymer antibodies are correlated with pain and fatigue severity in patients with fibromyalgia syndrome.
abstract: OBJECTIVE
  To investigate the prevalence of antipolymer antibody (APA) in patients with fibromyalgia (FM) and to examine its association with FM severity symptoms.
  
  
  METHODS
  The study population consisted of 79 FM patients and 75 controls: 32 with psoriatic arthritis and 43 with rheumatoid arthritis APA levels were indirectly assayed using a commercial ELISA kit from Corgenix (Westmister, Colorado, USA). Optical density (OD) values were recorded on duplicates of each of the reference and patient samples. Among clinical variables we investigated pain, measured according to visual analog scales (VAS: 0-100), fatigue, stiffness, anxiety, depression, all measured by VAS (0-100), and health status measured by Fibromyalgia Impact Questionnaire (FIQ).
  
  
  RESULTS
  Sixteen of the 79 FM patients (20.3%) and 12/78 controls (15.4%) were positive for APAs (P = 0.536). Following ROC analysis, area under curve (AUC) was 0.49 (95% CI: 0.40, 0.58). Focusing on FM patients, we observed a correlation between APA titre and pain (tau: - 0.221; P = 0.020) and fatigue (tau: - 0.205; P = 0.032) at univariate analysis. Binomial regression analysis, controlling for clinical and demographic variables, showed that pain (PPR: 0.923; P = 0.007) and fatigue (PPR: 0.948; P = 0.024) were significantly associated with APA test sensitivity.
  
  
  CONCLUSIONS
  APA test exhibited a low sensitivity in FM patients and it did not distinguish this group of patients from the controls enrolled in this study. Interestingly, positive APA test prevalence increased with less severe pain or fatigue.
authors.affiliation: Rheumatology Unit, L. Sacco University Hospital, Milan, Italy. sarzi@tiscali.it
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Sarzi-Puttini
authors.forename: Fabiola
authors.initials: F
authors.lastname: Atzeni
authors.forename: Manuela
authors.initials: M
authors.lastname: Di Franco
authors.forename: Nicola
authors.initials: N
authors.lastname: Lama
authors.forename: Alberto
authors.initials: A
authors.lastname: Batticciotto
authors.forename: Cristina
authors.initials: C
authors.lastname: Iannuccelli
authors.forename: Donata
authors.initials: D
authors.lastname: Dell'Acqua
authors.forename: Simona
authors.initials: S
authors.lastname: de Portu
authors.forename: Valeria
authors.initials: V
authors.lastname: Riccieri
authors.forename: Mario
authors.initials: M
authors.lastname: Carrabba
authors.forename: Dan
authors.initials: D
authors.lastname: Buskila
authors.forename: Andrea
authors.initials: A
authors.lastname: Doria
authors.forename: Guido
authors.initials: G
authors.lastname: Valesini
mesh_terms: D000328:Adult; D000906:Antibodies / Q000097:blood* / Q000276:immunology; D005221:Fatigue / Q000276:immunology / Q000503:physiopathology*; D005260:Female; D005356:Fibromyalgia / Q000097:blood / Q000276:immunology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000276:immunology / Q000503:physiopathology*; D011108:Polymers; D012720:Severity of Illness Index
chemical_list: D000906:Antibodies; D011108:Polymers