title: Large-scale analysis of tumor necrosis factor α levels in systemic lupus erythematosus.
abstract: OBJECTIVE
  Systemic lupus erythematosus (SLE) disease manifestations are highly variable among patients, and the prevalence of individual clinical features differs significantly by ancestry. Serum tumor necrosis factor α (TNFα) levels are elevated in some SLE patients and may play a role in disease pathogenesis. The aim of this study was to look for associations between serum TNFα levels, clinical manifestations of SLE, autoantibodies, and serum interferon-α (IFNα) levels in a large multiancestral SLE cohort.
  
  
  METHODS
  We studied serum TNFα levels in 653 SLE patients (214 African Americans, 298 European Americans, and 141 Hispanic Americans). TNFα was measured using an enzyme-linked immunosorbent assay, and IFNα was measured with a functional reporter cell assay. Stratified and multivariate analyses were used to detect associations in each ancestral background separately, with meta-analysis when appropriate.
  
  
  RESULTS
  Serum TNFα levels were significantly higher in SLE patients than in non-autoimmune disease controls (P < 5.0 × 10(-3)  for each ancestral background). High serum TNFα levels were positively correlated with high serum IFNα levels when tested in the same sample across all ancestral backgrounds (odds ratio range 1.76-1.86, P = 4.8 × 10(-3)  by Fisher's combined probability test). While serum TNFα levels alone did not differ significantly among SLE patients of different ancestral backgrounds, the proportion of patients with concurrently high levels of TNFα and IFNα was highest in African Americans and lowest in European Americans (P = 5.0 × 10(-3) ). Serum TNFα levels were not associated with autoantibodies, clinical criteria for the diagnosis of SLE, or age at the time of sampling.
  
  
  CONCLUSIONS
  Serum TNFα levels are high in many SLE patients, and we observed a positive correlation between serum TNFα and IFNα levels. These data support a role for TNFα in the pathogenesis of SLE across all ancestral backgrounds and suggest important cytokine subgroups within the disease.
authors.affiliation: University of Chicago, Chicago, Illinois.
authors.forename: Corinna E
authors.initials: CE
authors.lastname: Weckerle
authors.forename: Dorothy
authors.initials: D
authors.lastname: Mangale
authors.forename: Beverly S
authors.initials: BS
authors.lastname: Franek
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Kelly
authors.forename: Marissa
authors.initials: M
authors.lastname: Kumabe
authors.forename: Judith A
authors.initials: JA
authors.lastname: James
authors.forename: Kathy L
authors.initials: KL
authors.lastname: Moser
authors.forename: John B
authors.initials: JB
authors.lastname: Harley
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Niewold
mesh_terms: D000328:Adult; D001741:Black or African American; D001323:Autoantibodies / Q000097:blood; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D016898:Interferon-alpha / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000208:ethnology / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*; D044465:White People
chemical_list: D001323:Autoantibodies; D016898:Interferon-alpha; D014409:Tumor Necrosis Factor-alpha