title: [Capacity to predict a recurrence of lupus erythematosus using double-stranded anti-DNA antibodies and Farr technique].
abstract: BACKGROUND
  Patients with inactive systemic lupus erythematosus (SLE) and elevated high affinity double-stranded anti-DNA antibodies (anti-dsDNA), measured using Farr technique, would have a risk of relapse that fluctuates between 40 to 80% according to different series.
  
  
  OBJECTIVE
  To study the association between anti-dsDNA levels measured using Farr technique and disease activity and their predictive capacity for relapses.
  
  
  METHODS
  Anti-dsDNA antibodies were measured according to Farr method in 60 healthy subjects, 69 patients with other connective tissue diseases and in 120 patients with SLE. Farr positive were considered those individuals with anti-dsDNA levels over 10.4 IU/ml. Disease activity, assessed using MEX-SLEDAI score was related with anti-dsDNA levels in 101 patients. Forty seven patients with inactive disease were followed for 17 +/- 14 months.
  
  
  RESULTS
  Anti-dsDNA levels were 3 +/- 2.5 IU/ml (range 1-26) in subjects without LED, and 127 +/- 500 IU/ml (range 1-5280) in patients with LED. Sixty subjects had an active SLE and 43 (72%) were Farr positive; in 41 the disease was inactive and 13 (32%) were Farr positive (p < 0.001), OR 5.45. Twelve of the 47 followed patients had a relapse and 10 (83%) were Farr positive. Of those that did not have a relapse, 13 (37%) were Farr positive (p < 0.02, RR 5.22). Six of 15 patients that were followed for more than on year (40%), were Farr positive.
  
  
  CONCLUSIONS
  Elevated anti-dsDNA antibodies measured using Farr technique in patients with inactive generalised lupus erythematosus, predicted the risk of relapse. However less than half of patients with inactive disease and elevated Farr relapsed in a period of one year. The need to treat patients with inactive SLE and positive Farr should therefore be considered debatable.
authors.affiliation: Departamento de Inmunología Clínica y Reumatología, Facultad de Medicina, Pontificia Universidad Católica de Chile. massardo@med.puc.cl
authors.forename: L
authors.initials: L
authors.lastname: Massardo
authors.forename: M E
authors.initials: ME
authors.lastname: Martínez
authors.forename: R
authors.initials: R
authors.lastname: Pérez
authors.forename: V
authors.initials: V
authors.lastname: Ramírez
authors.forename: A
authors.initials: A
authors.lastname: Foradori
authors.forename: A
authors.initials: A
authors.lastname: González
authors.forename: F
authors.initials: F
authors.lastname: Radrigán
authors.forename: F
authors.initials: F
authors.lastname: Gutiérrez
authors.forename: S
authors.initials: S
authors.lastname: Jacobelli
mesh_terms: D000293:Adolescent; D000368:Aged; D000974:Antibodies, Antinuclear / Q000032:analysis*; D002648:Child; D004247:DNA / Q000276:immunology*; D005260:Female; D005544:Forecasting; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012008:Recurrence
chemical_list: D000974:Antibodies, Antinuclear; D004247:DNA
vernacular_title: Capacidad de predecir una recaída de lupus eritematoso generalizado, mediante anticuerpos anti-DNA de hebra doble, por la técnica de Farr.