Clinical features of IgG4-related retroperitoneal fibrosis among 407 patients with IgG4-related disease: a retrospective study.

Objectives IgG4-related disease (IgG4-RD) is recently recognized as a fibro-inflammatory condition featured by tumefactive lesions in multiple organs, and the retroperitoneum is one of the common involved sites. We undertook this study to compare detailed demographic, clinical and laboratory characteristics of IgG4-RD patients with retroperitoneum lesion (IgG4-RD RPF+) and retroperitoneum free IgG4-RD (IgG4-RD RPF-) in a large cohort. Methods We carried out a retrospective review of the medical records of 407 cases of IgG4-RD diagnosed at Peking University People's Hospital between March 2009 and May 2019. Results Among 407 patients, 58 had retroperitoneum affected. As compared with IgG4-RD RPF- patients, IgG4-RD RPF+ patients showed older age at disease onset and diagnosis. IgG4-RD RPF+ group involved more male patients. In terms of organ involvement, IgG4-RD RPF+ group was more frequently presented with kidney involvement, while salivary gland, lacrimal gland and pancreas were more prominent in the IgG4-RD RPF- group. In addition, the CRP, ESR level and creatinine level were significantly higher in IgG4-RD RPF+ patients, and hypocomplementemia were more common in this group. Conclusion We have revealed demographic, clinical and laboratory differences between IgG4-RD RPF+ and RPF- patients, which indicated potential differences in pathogenesis and important implications for the diagnosis and management of these two phenotypes.