title: Associations between antinuclear antibody staining patterns and clinical features of systemic lupus erythematosus: analysis of a regional Swedish register.
abstract: OBJECTIVE
  Antinuclear antibody (ANA) analysis by immunofluorescence (IF) microscopy remains a diagnostic hallmark of systemic lupus erythematosus (SLE). The clinical relevance of ANA fine-specificities in SLE has been addressed repeatedly, whereas studies on IF-ANA staining patterns in relation to disease manifestations are very scarce. This study was performed to elucidate whether different staining patterns associate with distinct SLE phenotypes.
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  One university hospital rheumatology unit in Sweden.
  
  
  METHODS
  The study population consisted of 222 cases (89% women; 93% Caucasians), where of 178 met ≥4/11 of the 1982 American College of Rheumatology (ACR-82) criteria. The remaining 20% had an SLE diagnosis based on positive IF-ANA (HEp-2 cells) and ≥2 typical organ manifestations at the time of diagnosis (Fries' criteria).
  
  
  METHODS
  The IF-ANA staining patterns homogenous (H-ANA), speckled (S-ANA), combined homogenous and speckled (HS-ANA), centromeric (C-ANA), nucleolar (N-ANA)±other patterns and other nuclear patterns (oANA) were related to disease manifestations and laboratory measures. Antigen-specificities were also considered regarding double-stranded DNA (Crithidia luciliae) and the following extractable nuclear antigens: Ro/SSA, La/SSB, Smith antigen (Sm), small nuclear RNP (snRNP), Scl-70 and Jo-1 (immunodiffusion and/or line-blot technique).
  
  
  RESULTS
  54% of the patients with SLE displayed H-ANA, 22% S-ANA, 11% HS-ANA, 9% N-ANA, 1% C-ANA, 2% oANA and 1% were never IF-ANA positive. Staining patterns among patients meeting Fries' criteria alone did not differ from those fulfilling ACR-82. H-ANA was significantly associated with the 10th criterion according to ACR-82 ('immunological disorder'). S-ANA was inversely associated with arthritis, 'immunological disorder' and signs of organ damage.
  
  
  CONCLUSIONS
  H-ANA is the dominant IF-ANA pattern among Swedish patients with SLE, and was found to associate with 'immunological disorder' according to ACR-82. The second most common pattern, S-ANA, associated negatively with arthritis and organ damage.
authors.affiliation: Rheumatology/AIR, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: Martina
authors.initials: M
authors.lastname: Frodlund
authors.forename: Orjan
authors.initials: O
authors.lastname: Dahlström
authors.forename: Alf
authors.initials: A
authors.lastname: Kastbom
authors.forename: Thomas
authors.initials: T
authors.lastname: Skogh
authors.forename: Christopher
authors.initials: C
authors.lastname: Sjöwall
keywords: Antinuclear antibodies; Immunofluorescence microscopy; Organ damage; Ro/SSA; Systemic lupus erythematosus