title: Decreased levels of interleukin-12p40 in the serum of patients with Whipple's disease.
abstract: BACKGROUND
  An impaired production of interleukin (IL)-12 and T cell interferon-gamma (IFN-gamma) of in vitro stimulated monocytes has been discussed as a pathogenic factor in Whipple's disease (WD). It is unclear whether this defect of cellular immunity is translated to the humoral immune system and to serum correlates.
  
  
  METHODS
  We analyzed the serum of 40 patients with Whipple's disease in various degrees of disease activity by sandwich enzyme-linked immunosorbent assay for differences in cytokine and cell adhesion molecule concentrations compared with age- and sex-matched controls.
  
  
  RESULTS
  We observed a highly significant reduction of IL-12p40 levels (patients, 0.18+/-0.05 ng/ml (mean+/-SEM); controls, 3.19+/-0.39 ng/ml; p<0.01) in all stages of disease activity, whereas the concentration of IL-12p70 was comparable with controls. Furthermore, we observed a slight decrease in tumour necrosis factor alpha (TNF-alpha) concentrations in the serum of patients (patients, 6.36+/-0.90 pg/ml; controls, 10.5+/-1.23 pg/ml; p<0,05). The levels of other cytokines such as IFN-gamma, IL-2, IL-13 and transforming growth factor beta, as well as soluble cell adhesion molecules lymphocyte function-associated antigen 3 and intercellular adhesion molecule 1, were not significantly different compared with controls. Levels of immunoglobulin G2 (IgG2) measured in the serum of WD patients were below normal in 24 of 29 patients and were even below the 95% confidence interval in 10 patients.
  
  
  CONCLUSIONS
  Our data demonstrate a persistent defect of the cellular immune response with decreased serum concentrations of IL-12p40 and TNF-alpha and decreased IgG2 levels in a large group of WD patients. These data support as in vivo finding the results obtained in previous investigations with stimulated monocytes/lymphocytes. The isolated decrease in IL-12p40 may hint at possible defects in the IL-12/IFN-gamma promoter system.
authors.affiliation: Department of Dermatology, The University of the Saarland, 66421, Homburg/Saar, Germany. haakal@uniklinik-saarland.de
authors.forename: A
authors.initials: A
authors.lastname: Kalt
authors.forename: T
authors.initials: T
authors.lastname: Schneider
authors.forename: S
authors.initials: S
authors.lastname: Ring
authors.forename: J
authors.initials: J
authors.lastname: Hoffmann
authors.forename: M
authors.initials: M
authors.lastname: Zeitz
authors.forename: A
authors.initials: A
authors.lastname: Stallmach
authors.forename: D H
authors.initials: DH
authors.lastname: Persing
authors.forename: T
authors.initials: T
authors.lastname: Marth
mesh_terms: D015415:Biomarkers / Q000097:blood; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D018664:Interleukin-12 / Q000097:blood; D053762:Interleukin-12 Subunit p40 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D008061:Whipple Disease / Q000097:blood*
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D053762:Interleukin-12 Subunit p40; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12