title: Serum levels of tumour necrosis factor family members a proliferation-inducing ligand (APRIL) and B lymphocyte stimulator (BLyS) are inversely correlated in systemic lupus erythematosus.
abstract: OBJECTIVE
  To determine whether serum levels of a proliferation-inducing ligand (APRIL) are altered in patients with systemic lupus erythematosus (SLE), and correlate with disease parameters.
  
  
  METHODS
  Clinical and biological parameters were analysed for 43 patients that fulfilled American College of Rheumatology (ACR) criteria for SLE classification and were positive for anti-double-stranded DNA (dsDNA) antibodies at least once in their medical records. Tests included measurement of serum levels of the tumour necrosis factor (TNF) family members APRIL and B lymphocyte stimulator (BLyS; a cytokine shown to promote SLE disease).
  
  
  RESULTS
  Median APRIL levels were elevated in patients with SLE compared to patients with osteoarthritis and healthy controls, but did not correlate with the SLE Disease Activity Index (SLEDAI). APRIL serum levels showed an inverse correlation with BLyS serum levels (r = -0.339; p = 0.03). For patients with SLE with positive anti-dsDNA titres (>40 arbitrary units (AU)/ml) at inclusion (n = 25), circulating APRIL was inversely correlated with BLyS levels (r = -0.465; p = 0.022) and anti-dsDNA antibody titres (r = -0.411; p = 0.046). In a follow-up study at their second visit, 27 patients showed an inverse correlation of APRIL serum levels with BLyS (r = -0.398; p = 0.03) as well as with anti-dsDNA (r = -0.408; p = 0.03) titres and SLEDAI (r = -0.408; p = 0.01).
  
  
  CONCLUSIONS
  The inverse correlation observed between APRIL and BLyS suggests that APRIL acts as a protective factor. APRIL and BLyS may thus have opposite roles in SLE, which must be considered when defining therapeutic applications of these cytokines.
authors.affiliation: Service d'Immuno-Rhumatologie Université Montpellier, France. j-morel@chu-montpellier.fr
authors.forename: J
authors.initials: J
authors.lastname: Morel
authors.forename: C
authors.initials: C
authors.lastname: Roubille
authors.forename: L
authors.initials: L
authors.lastname: Planelles
authors.forename: C
authors.initials: C
authors.lastname: Rocha
authors.forename: L
authors.initials: L
authors.lastname: Fernandez
authors.forename: C
authors.initials: C
authors.lastname: Lukas
authors.forename: M
authors.initials: M
authors.lastname: Hahne
authors.forename: B
authors.initials: B
authors.lastname: Combe
mesh_terms: D000208:Acute Disease; D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood; D001323:Autoantibodies / Q000097:blood; D053264:B-Cell Activating Factor / Q000097:blood*; D016022:Case-Control Studies; D004247:DNA / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13 / Q000097:blood*; D055815:Young Adult
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D053264:B-Cell Activating Factor; C114631:TNFSF13 protein, human; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13; D004247:DNA