Retroperitoneal Fibrosis in Chronic Kidney Disease / General Medicine

We report two cases of retroperitoneal fibrosis that emerged during a clinical course of moderate chronic kidney disease. In both cases, we observed an elevation in the serum CRP and IgG4 levels without an increase in the white blood cell count. The patients were treated with prednisolone. Their clinical conditions improved with a decrease in the serum IgG4 to total IgG ratio. The present cases suggest the importance of a differential diagnosis of retroperitoneal fibrosis in the medical care of chronic kidney disease patients, and we propose a useful biomarker for retroperitoneal fibrosis, which we suspect is associated with IgG4-related disease.