title: BAFF (B cell activating factor) transcript level in peripheral blood of patients with SLE is associated with same-day disease activity as well as global activity over the next year.
abstract: OBJECTIVE
  Quantitating gene expression is a potential method of developing biomarkers in systemic lupus erythematosus (SLE). Because of the known pathological role of B cell activating factor (BAFF) in SLE, we explored the association between BAFF gene expression and clinical activity in SLE.
  
  
  METHODS
  A total of 275 patients with SLE completed this phase of a prospective observational study. At entry into the study, the BAFF gene expression levels were determined in peripheral blood RNA. Serum concentration of BAFF protein was also measured. We then determined clinical associations with SLE disease history, SLE activity on the same day and SLE activity over the course of the next year.
  
  
  RESULTS
  Elevated BAFF gene expression was associated with a history of more leucopenia and serologically with more autoantibodies (anti-dsDNA, anti-Sm, anti-Ro, anti-La and anti-RNP) and low complement. Patients with higher amounts of BAFF transcript had higher measured levels of clinical disease activity. Initial high levels of BAFF gene expression also predicted increased disease activity over the course of the next year. In contrast, serum concentration of BAFF protein was not strongly associated with same-day global disease activity or with future disease activity.
  
  
  CONCLUSIONS
  BAFF gene expression level is associated with clinical and serological SLE activity on the same day and predictive of clinical activity over the next year. BAFF gene expression is a better measure and predictor of SLE disease activity than the serum BAFF protein level.
authors.affiliation: Division of Rheumatology , Johns Hopkins University School of Medicine , Baltimore, Maryland , USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Zollars
authors.affiliation: Biogen Idec , Cambridge, Massachusetts , USA.
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Bienkowska
authors.affiliation: Biogen Idec , Cambridge, Massachusetts , USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Czerkowicz
authors.affiliation: Biogen Idec , Cambridge, Massachusetts , USA.
authors.forename: Norm
authors.initials: N
authors.lastname: Allaire
authors.affiliation: Biogen Idec , Cambridge, Massachusetts , USA.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Ranger
authors.affiliation: Epidemiology and Public Health, University of Maryland , Baltimore, Maryland , USA.
authors.forename: Laurence
authors.initials: L
authors.lastname: Magder
authors.affiliation: Division of Rheumatology , Johns Hopkins University School of Medicine , Baltimore, Maryland , USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Petri
keywords: Cytokines; Disease Activity; Systemic Lupus Erythematosus