Simple urine test could transform kidney care

In a finding set to change the way disease is monitored, Chandra Mohan, an international expert and pioneer in lupus research at the University of Houston, is reporting that urine samples can indicate lupus nephritis in a noninvasive manner, without the need for repeat and painful renal biopsies.

This would be transformative for the lives of 5 million people worldwide who have some form of systemic lupus erythematosus, or lupus, with 50% of those experiencing kidney disease including lupus nephritis.

Lupus is an autoimmune disease that occurs when the body attacks its own tissues and organs. Lupus nephritis is one of the most frequent and severe clinical manifestations of SLE, and the leading cause of death. Death directly attributable to kidney disease occurs in 5% to 25% of patients with lupus nephritis within five years of onset.

The urgent need for noninvasive biomarkers

“Renal biopsy is invasive and inconvenient and associated with potential complications such as bleeding and infection. The reading of a renal biopsy by pathologists is subjective with substantial inter-pathologist discordance,” reports Mohan, Hugh Roy and Lillie Cranz Cullen Endowed Professor of Biomedical Engineering, in the Journal of Clinical Investigation.

“Noninvasive biomarkers precisely predicting histological activity and chronicity are urgently needed,” said Mohan, Professor of Biomedical Engineering at UH.

To identify urinary protein biomarkers that could predict kidney damage, Mohan’s team used proteomics—a method that examines all the proteins in a sample to find those linked to disease—to analyze 1,317 urine samples collected at the time of biopsy from subjects with lupus nephritis.

“In this study, we found that 57 different proteins in urine were much higher in subjects whose kidneys showed more signs of active damage,” said Mohan. “Under the microscope we found these higher protein levels were linked to certain changes like swelling of blood vessel cells, areas of tissue death and clusters of damaged cells. Many of these proteins came from immune cells and showed that there was inflammation happening in the kidneys.”

Other proteins found were linked to long-term scarring in the kidneys.

“Overall, the results indicate that by measuring certain proteins in urine, doctors might be able to tell how active or long-lasting someone’s lupus-related kidney disease is, and they could check kidney health without having to do another biopsy,” said Mohan.