Novel round cells in urine sediment and their clinical implications.

Background Voided urine contains a variety of cells from the kidney and urinary tract and urinalysis provides us various information by investigating cellular components. We investigated urine sediment from renal impaired patients. Results We found ‘round cell’ to be distinct from known cells in sediment and is close to proximal convoluted tubule-derived cells based on morphology and molecular marker expression (GGT1 but not podocalyxin). Also it was positive for undifferentiated cell markers, including PAX2, WT1, OSR1, and SIX2. They were observed in end-stage renal failure patients and the number of cells was correlated with the severity of chronic kidney disease. A prospective analysis revealed that patients who had more round cells were more likely to require hemodialysis within a year. Conclusion Round cells are a novel marker that can be used to predict the need for hemodialysis.