Role of interleukin-32 in the mechanism of chronic inflammation in IgG4-related disease and as a predictive biomarker for drug-free remission

Abstract

Objectives: In immunoglobulin (Ig) G4-related disease (IgG4-RD), the mechanism of chronic inflammation and predictive factors for drug-free remission is still unclear. To examine the issues, we focused on tuberculosis, a chronic infection, and on the role of interleukin (IL)-32.

Methods: We examined the positive rate of QuantiFERON TB-2G (QFT-2G) in 126 patients with IgG4-RD, and compared with the rate in the general population. Furthermore, specimens of submandibular glands from the maintenance treatment group and drug-free group of IgG4-RD and specimens of small salivary glands from primary Sjögren’s syndrome (SS) were stained with anti-IL-32 antibody and anti-protease-activated receptor 2 antibody, and the number of positive cells was compared between these groups.

Results: The positive rate of QFT-2G was 19.8% in IgG4-RD patients, which is higher than in the general population. The expression of IL-32 and PAR2 in the submandibular glands of the maintenance treatment group of IgG4-RD was significantly greater than that of the drug-free remission group and SS patients.

Conclusions: This study indicates the possibility that IL-32 is associated with chronic inflammation and that it can be a predictive factor for drug-free remission in IgG4-RD.

Keywords::

• Chronic inflammation
• Germinal center
• IgG4-related disease
• Interleukin-32
• Tuberculosis

Conflict of interest

This work was supported by Minako Shiokawa Young Investor’s Award for Collagen Disease Research, Japan Rheumatism Foundation and the Research on Measures for Intractable Diseases Project matching fund subsidy from the Ministry of Health, Labour, and Welfare, Japan. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.