Salivary gland involvement disparities in clinical characteristics of IgG4-related disease: a retrospective study of 428 patients

Objectives. IgG4-related disease (IgG4-RD) has recently been recognized as a fibro-inflammatory condition featuring tumefactive lesions in multiple organs, and the salivary gland is one of the most commonly involved sites. We undertook this study to compare detailed demographic, clinical and laboratory characteristics of IgG4-RD patients with salivary gland lesions (IgG4-RD SG+) and salivary-gland-free IgG4-RD (IgG4-RD SG-) in a large cohort. Methods. We carried out a retrospective review of the medical records of 428 cases of IgG4-RD diagnosed at Peking University People's Hospital between March 2006 and May 2018. Results. Among 428 patients, 249 had salivary glands that were affected. IgG4-RD SG+ patients showed younger age at disease onset and diagnosis, and a longer interval between symptom onset and diagnosis. The IgG4-RD SG+ group involved more female patients, and allergic diseases were more common in this group. In terms of organ involvement, the IgG4-RD SG+ group were more frequently presented with lacrimal gland involvement, while lymph node, retroperitoneal fibrosis, pancreas, biliary system, kidney and aorta were more prominent in the IgG4-RD SG- group. In addition, the serum IgG4 level, IgG4/IgG ratio and IgE level were significantly higher in IgG4-RD SG+ patients. Patients with eosinophilia were more common in the IgG4-RD SG+ group, while elevated ESR, CRP and positive ANA were more common in the IgG4-RD SG- group. Conclusion. We have revealed demographic, clinical and laboratory differences between IgG4-RD SG+ and SG- patients, which indicated potential differences in pathogenesis and important implications for the diagnosis and management of these two phenotypes.