title: B lymphocyte stimulator expression in pediatric systemic lupus erythematosus and juvenile idiopathic arthritis patients.
abstract: OBJECTIVE
  To assess the expression of B lymphocyte stimulator (BLyS) in patients with pediatric systemic lupus erythematosus (SLE) or juvenile idiopathic arthritis (JIA).
  
  
  METHODS
  Blood samples collected from patients with pediatric SLE (n = 56) and patients with JIA (n = 54) at the beginning and end of a 6-month interval were analyzed for plasma BLyS protein levels by enzyme-linked immunosorbent assay and for blood leukocyte full-length BLyS and DeltaBLyS messenger RNA (mRNA) levels by quantitative real-time polymerase chain reaction (normalized to 18S expression). Healthy siblings (n = 34) of these patients served as controls.
  
  
  RESULTS
  In pediatric SLE, plasma BLyS protein and blood leukocyte BLyS mRNA levels were each significantly elevated, and plasma BLyS protein levels, but not blood leukocyte BLyS mRNA levels, were correlated with disease activity. In contrast, plasma BLyS protein levels were normal in JIA despite blood leukocyte BLyS mRNA levels being elevated to degrees similar to those in pediatric SLE. Among JIA patients, neither BLyS parameter was correlated with disease activity. In both pediatric SLE and JIA, the BLyS expression profiles remained stable at 6 months.
  
  
  CONCLUSIONS
  Our findings indicate that, as previously noted in adult SLE, plasma BLyS protein and blood leukocyte BLyS mRNA levels are elevated in pediatric SLE. The correlation of plasma BLyS protein levels with disease activity points to BLyS as a candidate therapeutic target in pediatric SLE. Contrary to previous observations in adults with rheumatoid arthritis, plasma BLyS protein levels are normal in JIA despite elevated blood leukocyte BLyS mRNA levels. The absence of correlation between either of the BLyS parameters and disease activity in JIA calls for circumspection prior to assigning BLyS as a candidate therapeutic target in this disorder.
authors.affiliation: Childrens Hospital Los Angeles, Los Angeles, CA 90033, USA. sandy-hong@uiowa.edu
authors.forename: Sandy D
authors.initials: SD
authors.lastname: Hong
authors.forename: Andreas
authors.initials: A
authors.lastname: Reiff
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Yang
authors.forename: Thi-Sau
authors.initials: TS
authors.lastname: Migone
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Ward
authors.forename: Katherine
authors.initials: K
authors.lastname: Marzan
authors.forename: Bracha
authors.initials: B
authors.lastname: Shaham
authors.forename: Wee Choo
authors.initials: WC
authors.lastname: Phei
authors.forename: Judith
authors.initials: J
authors.lastname: Garza
authors.forename: Bram
authors.initials: B
authors.lastname: Bernstein
authors.forename: William
authors.initials: W
authors.lastname: Stohl
mesh_terms: D000293:Adolescent; D001171:Arthritis, Juvenile / Q000097:blood*; D053264:B-Cell Activating Factor / Q000097:blood*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D012333:RNA, Messenger / Q000097:blood; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D053264:B-Cell Activating Factor; D012333:RNA, Messenger