Researchers at Trinity College Dublin (TCD) have developed a test which has the potential to improve the care of people living with kidney vasculitis.

One of the leading causes of kidney failure is a group of diseases called glomerulonephritis. One of these conditions - ANCA vasculitis - occurs in 100 new people in Ireland each year. Currently, an estimated 1,000 people in Ireland are living with vasculitis.  

However, detecting active kidney vasculitis is difficult. A definitive diagnosis requires a kidney biopsy, therefore, non-invasive biomarkers of active kidney inflammation are needed for early detection of active disease.

If left untreated, this disease can lead to irreversible scarring and kidney failure requiring dialysis or transplantation. Up to 50% of people with kidney vasculitis develop kidney failure over time.

The TCD team, working with researchers from the ADAPT SFI Centre and Queen’s University Canada, have identified a protein (urine soluble CD163), which is detected in urine when kidney vasculitis is active.

The discovery of this new biomarker has the potential to improve the personalisation of patient care, allowing more accurate and earlier diagnoses of kidney injury. This could lead to reduced rates of progressive kidney failure, which would benefit patients, but also reduce healthcare costs.

With ANCA vasculitis and other inflammatory kidney diseases, easily accessible, non-invasive tests for active kidney disease are urgently needed. Clinical translation of possible diagnostic tests requires rigorous clinical assessment and the use of a clinical grade test.

Collaborating with industry, the researchers have developed an accurate diagnostic grade urine test, which is starting to be used globally. This diagnostic urine test was assessed in people with active kidney vasculitis, healthy people and people with other forms of kidney disease.

This information was used to define an accurate reference range and then patients were prospectively studied throughout Ireland. The researchers have shown that urine soluble CD163 displays high precision in diagnosing active renal inflammation, findings that have the potential to transform the care of patients living with the disease.

The test is accurate, non-invasive, cost-effective, requires minimal sample processing and is remarkably stable over time. This means that urine soluble CD163 can be measured using existing equipment in clinical hospital laboratories worldwide. Furthermore, it is not affected by a urine sample being left for a period at room temperature or by transfer to a centre of expertise for measurement.

Clinical studies from the team have shown its high level of accuracy in identifying kidney vasculitis disease activity. As a result, urine soluble CD163 is ready for translation and use in the clinical care of people with suspected kidney vasculitis.

“We have shown that urine soluble CD163 has the potential to transform the care of patients living with kidney vasculitis by developing a clinical grade assay which is highly accurate in diagnosing kidney vasculitis flares. This is highly significant and will improve the care of people living with vasculitis,” explained the study’s lead author, Dr Sarah Moran, of Queen’s University, Canada.

According to senior author, Dr Mark Little of TCD, the clinical use of urine soluble CD163 measurement “has already helped us to avoid the need for invasive kidney biopsy in patients with vasculitis”.

“Such translation of a technology, from basic immunology observations in the Trinity Translational Medicine Institute, into a clinical test that is now being used across the world, is a rare event. It would not have been possible without broad multidisciplinary input from TTMI, clinical collaborators around Ireland, data science expertise from the ADAPT SFI Centre, the Irish vasculitis patient population, the research funders and industry collaborators,” Dr Little added.

Details of these findings have been published in the Journal of the American Society of Nephrology.