title: Clinical differences between Thai systemic sclerosis patients with positive versus negative anti-topoisomerase I.
abstract: BACKGROUND
  Anti-topoisomerase I antibody (ATA) carries an increased risk of systemic sclerosis (SSc) internal organ involvement. There have been no published comparisons of the clinical characteristics of patients positive and negative for ATA in Thailand, where the positive rate for ATA is higher than among Caucasians.
  
  
  OBJECTIVE
  To define the clinical differences between SSc, positive versus negative, for ATA.
  
  
  METHODS
  A retrospective cohort study was performed among SSc patients over 18 at Srinagarind Hospital, Khon Kaen University, Thailand, during January 2006-December 2013. SSc-overlap syndrome was excluded.
  
  
  RESULTS
  Two hundred and ninety-four SSc patients were included (female : male 2.5 : 1). The majority (68.6%) were the diffuse cutaneous SSc subset (dcSSc). ATA was positive in 252 patients (85.7%), among whom 71.7% had dcSSc and 28.2% limited cutaneous SSc (lcSSc). Using a multivariate analysis, hand deformity had a significantly positive association with ATA (odds ratio [OR] 7.01; 95% CI 1.02-48.69), whereas being anti-centromere (ACA) positive had a negative association (OR 0.17; 95% CI 0.03-0.92). After doing a subgroup analysis of the SSc subset, the median duration of disease at time of pulmonary fibrosis detection among ATA positive dcSSc was significantly shorter than the ATA negative group (1.05 vs. 6.77 years, P = 0.01). Raynaud's phenomenon (RP) at onset was significantly more frequent in lcSSc sufferers who were ATA negative than those who were ATA positive (90.5% vs. 56.9%, P = 0.005).
  
  
  CONCLUSIONS
  A high prevalence of ATA positivity was found among Thai SSc patients and this was associated with a high frequency of hand deformity, ACA negativity, a short duration of pulmonary fibrosis in dcSSc and a lower frequency of RP in lcSSc.
authors.affiliation: Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Chingching
authors.initials: C
authors.lastname: Foocharoen
authors.affiliation: Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Prangsuporn
authors.initials: P
authors.lastname: Suwannachat
authors.affiliation: Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Sittichai
authors.initials: S
authors.lastname: Netwijitpan
authors.affiliation: Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Ajanee
authors.initials: A
authors.lastname: Mahakkanukrauh
authors.affiliation: Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Siraphop
authors.initials: S
authors.lastname: Suwannaroj
authors.affiliation: Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Ratanavadee
authors.initials: R
authors.lastname: Nanagara
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D004264:DNA Topoisomerases, Type I / Q000276:immunology*; D005260:Female; D006227:Hand Deformities, Acquired / Q000453:epidemiology / Q000276:immunology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D011658:Pulmonary Fibrosis / Q000453:epidemiology / Q000276:immunology; D011928:Raynaud Disease / Q000453:epidemiology / Q000276:immunology; D012189:Retrospective Studies; D012307:Risk Factors; D045743:Scleroderma, Diffuse / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D045745:Scleroderma, Limited / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D012698:Serologic Tests; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D004264:DNA Topoisomerases, Type I; C528909:TOP1 protein, human
keywords: anti-Scl70; anti-topoisomerase I; autoimmune disease; scleroderma; systemic sclerosis