Total lesion glycolysis as an IgG4-related disease activity marker

Abstract

Objectives. 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.

Keywords:

• FDG-PET
• IgG4-related disease
• Soluble IL-2 receptor
• Total lesion glycolysis

Acknowledgments

We thank Drs. Y. Imura, M. Hashimoto, R. Nakashima, N. Yukawa, T. Nojima, D. Kawabata, T. Usui, K. Ohmura, and T. Fujii (Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University) for their contributions to clinical practice.

Conflict of interest

The authors declare no conflict of interests. This study was supported by grants from the respiratory failure research group and the IgG4-related disease research group of the Ministry of Health, Labour and Welfare, Japan. The funding source did not have any role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.

Supplementary material available online

Supplementary Figures 1, 2 and Table 1.