Serum soluble interleukin-2 receptor as a biomarker in immunoglobulin G4-related disease

Abstract

Objectives: Serum soluble interleukin-2 (IL-2) receptor (sIL-2R) might reflect disease activity in immunoglobulin G4-related disease (IgG4-RD). We aimed to elucidate the clinical significance of blood markers, including sIL-2R, in patients with IgG4-RD.

Methods: We enrolled 59 patients with IgG4-RD and investigated the association between blood markers (white blood cells, C-reactive protein, sIL-2R, IgG, IgG4, IgE, total hemolytic complement), and clinical indices.

Results: At baseline, serum sIL-2R (Rs = 0.532, p < .001) and IgG4 (Rs = 0.545, p < .001) levels showed significant correlation to the number of organs involved. During follow-up period (median, 70 months; range, 7–195 months), 40 patients were treated with corticosteroids. Receiver operating characteristic (ROC) analysis showed that baseline sIL-2R levels most accurately predicted patients requiring glucocorticoid treatment (area under the ROC curve, 0.807). Among the 46 patients who improved, sIL-2R and IgG4 levels decreased in 42 and 41 patients, respectively. Among them, serum sIL-2R levels decreased to a normal range in 42 patients (91%), whereas IgG4 levels normalized in 19 (41%).

Conclusion: The serum sIL-2R level is a potential biomarker for IgG4-RD that may reflect the number of involved organs and may predict patients requiring glucocorticoid treatment.

Keywords:

• Biomarker
• IgG4-related disease
• soluble IL-2 receptor

Acknowledgements

The authors thank Dr. Kiminobu Tanizawa (Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University) and Dr Kohei Ikezoe (Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University) for their contribution to clinical practice of the patients.

Conflict of interest

None.

Additional information

Funding

This study was supported by grants from the Practical Research Project for Rare/Intractable Diseases from Japan Agency for Medical Research and development, AMED (No. 16ek0109051h0003), the Research Committee to establish diagnostic criteria and development of treatment for systemic IgG4-related sclerosing disease, supported by the Research Program of Intractable Disease, the Ministry of Health, Labor, and Welfare of Japan (No. H26-Nanchi-Ippan-050), and the Japan Society for the Promotion of Science (No. 26461187). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.