title: A pilot study of the use of 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography to assess the distribution of activated lymphocytes in patients with systemic lupus erythematosus.
abstract: OBJECTIVE
  The 2-[(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) technique provides information on uptake and metabolism of glucose in various tissues. Compared with resting cells, activated lymphocytes take up radioactively labeled glucose analog at a higher rate, which makes it possible to identify lymphoid organs with higher concentrations of activated lymphocytes. This study was undertaken to compare the pattern of PET images and quantitative FDG uptake in lymphoid organs of patients with active systemic lupus erythematosus (SLE) versus patients with inactive SLE and to correlate these findings with peripheral blood lymphocyte phenotypes.
  
  
  METHODS
  Ten patients with active SLE and 9 patients with inactive SLE were studied. FDG-PET images were obtained from the inguinal region to above the ear, starting at 60 minutes after injection of FDG. Standardized uptake values using lean body mass were determined over areas of interest.
  
  
  RESULTS
  Both patients with active lupus and those with inactive lupus had increased FDG uptake in lymph nodes when compared with healthy volunteers, and there was no statistically significant difference between the 2 groups of lupus patients. Thymic uptake was demonstrated in 5 of 10 patients with active lupus compared with 0 of 9 patients with inactive disease. Three of the 5 patients with active SLE who were over 29 years of age had thymic uptake. Of the activation markers tested, only the CD3/CD71 population of cells was significantly different between the patient groups, with an increased percentage in the active disease group (P = 0.0247).
  
  
  CONCLUSIONS
  Increased FDG uptake in lymph nodes of both patients with active SLE and patients with inactive SLE suggests that metabolic, and probably immunologic, activity is enhanced not only in active, but also in clinically quiescent, disease. The increased thymic uptake observed only in patients with active disease suggests that the thymus plays an important role during periods of disease activity.
authors.affiliation: National Institute of Arthritis and Musculoskeletal Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Miroslawa
authors.initials: M
authors.lastname: Nowak
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Carrasquillo
authors.forename: Cheryl H
authors.initials: CH
authors.lastname: Yarboro
authors.forename: Steven L
authors.initials: SL
authors.lastname: Bacharach
authors.forename: Millie
authors.initials: M
authors.lastname: Whatley
authors.forename: Xavier
authors.initials: X
authors.lastname: Valencia
authors.forename: Kazuki
authors.initials: K
authors.lastname: Takada
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Brust
authors.forename: Gabor G
authors.initials: GG
authors.lastname: Illei
mesh_terms: D000328:Adult; D015415:Biomarkers; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000000981:diagnostic imaging* / Q000276:immunology*; D008214:Lymphocytes / Q000000981:diagnostic imaging* / Q000276:immunology; D008221:Lymphoid Tissue / Q000000981:diagnostic imaging / Q000276:immunology; D008875:Middle Aged; D010865:Pilot Projects; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D015415:Biomarkers; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18