title: Total lesion glycolysis as an IgG4-related disease activity marker.
abstract: OBJECTIVE
  2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) was reported to be useful for monitoring immunoglobulin G4-related disease (IgG4-RD); however, a quantitative FDG-PET/CT analysis such as total lesion glycolysis (TLG) has not yet been conducted. This study aimed to investigate whether TLG would correlate with serum markers in IgG4-RD, and the utility of TLG for disease monitoring.
  
  
  METHODS
  This retrospective study included 17 patients (12 men; median age, 62 years) who were followed up at Kyoto University Hospital and underwent FDG-PET/CT from April 2009 to November 2013. TLG was calculated for the involved lesions. Correlations between serum markers [IgG4, soluble IL-2 receptor (sIL-2R), lactate dehydrogenase (LDH), and C-reactive protein (CRP)] and TLG concomitant with FDG-PET/CT scans were investigated. Serial changes in TLG were assessed in patients who underwent follow-up FDG-PET/CT (n = 6).
  
  
  RESULTS
  The calculated median (IQL) TLG value was 154.8 (63.7-324.4). A significant correlation was found between the sIL-2R level and TLG (P = 0.001, rs = 0.763). In contrast, no correlations were found between the IgG4, LDH, or CRP levels and TLG. Increased or decreased TLG corresponded with clinical disease improvement or worsening.
  
  
  CONCLUSIONS
  TLG correlated significantly with the serum sIL-2R level and may be useful for disease monitoring in IgG4-RD.
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University , Kyoto , Japan.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Nakatsuka
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Handa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nobashi
authors.forename: Hajime
authors.initials: H
authors.lastname: Yoshihuji
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Tanizawa
authors.forename: Kohei
authors.initials: K
authors.lastname: Ikezoe
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sokai
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Hirai
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chin
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
authors.forename: Tsuneyo
authors.initials: T
authors.lastname: Mimori
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology; D006019:Glycolysis; D006801:Humans; D007154:Immune System Diseases / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism*; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000494:pharmacology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG-PET; IgG4-related disease; Soluble IL-2 receptor; Total lesion glycolysis