Scandinavian journal of rheumatology
-
Scand. J. Rheumatol. · Jul 2019
IgG4-related disease in patients with newly diagnosed idiopathic retroperitoneal fibrosis: a population-based Danish study.
Objectives: IgG4-related disease (IgG4-RD) may present as 'idiopathic' retroperitoneal fibrosis (IRPF). We aimed to determine the occurrence of IgG4-retroperitoneal fibrosis (IgG4-RPF) in a nationwide study on patients with newly diagnosed IRPF, and to compare histopathological, imaging, and clinical features in the IgG4-RPF and non-IgG4-RPF subsets. Method: The National Danish Pathology Register was searched for biopsy codes relating to retroperitoneal tissue from 1 January 2004 to 31 December 2013. ⋯ There was a positive correlation between tissue IgG4-positive plasma cells and eosinophil cell count in patients with IgG4-RPF (rho = 0.50, p = 0.043). Conclusion: Forty-five per cent of this nationwide study population with newly diagnosed IRPF could be reclassified with IgG4-RPF. The association between high numbers of IgG4-bearing plasma cells and histopathological features of IgG4-RPF supports IgG4-bearing plasma cells with a perturbed distribution between IgG4 and total IgG being implicated in the pathogenesis of IgG4-RPF.