A new study of a rare disease – called IgA vasculitis nephritis – helps identify which patients are more likely to experience a decline in kidney function over time, indicating children are at higher risk than adults. The results, published in the
Clinical Journal of the American Society of Nephrology, also suggest health-care professionals monitor certain subgroups of patients, and especially children, longer due to fluctuations in kidney function.
IgA nephropathy is an autoimmune condition that causes inflammation in the kidneys. However, sometimes this inflammation also affects other parts of the body, such as the skin, joints or gastrointestinal tract, in which case the condition is called IgA vasculitis nephritis. With either condition, a kidney tissue sample (biopsy) is taken and analyzed in a lab to confirm a diagnosis and anticipate how the person’s disease may evolve over time.
Dr. Sean Barbour, who is a researcher with the University of British Columbia’s Division of Nephrology, a leading expert in IgA nephropathy, and Medical Lead, BC Renal Glomerulonephritis (GN) Registry, sought to better understand the differences between these two conditions, especially when analyzing kidney biopsies. Through an international collaboration, Barbour and his colleagues recruited patients from more than 10 other countries. In total, they analyzed kidney biopsies from 262 children and 99 adults with IgA vasculitis nephritis, categorizing people based on the features of their samples and their disease progression.
The results reveal which patients are at high risk of experiencing more aggressive disease. Whereas one group of patients tended to have stable disease, another group – predominantly involving children – tended to see a short-term improvement in kidney function before experiencing a bigger decline.
“I think what this means is that anyone in the group at risk of long-term kidney decline, which includes children, need to be followed for many years before we can be confident that their kidney function isn’t declining,” says Barbour. “It also means that maybe our current treatment isn’t adequate – we may need to consider more sustained periods of treatment, to prevent kidney function decline down the road.”
Importantly, the researchers confirmed that a scoring system used to analyze kidney biopsies of people with IgA nephropathy (called MEST-C) could be applied to those with IgA vasculitis nephritis, to better predict their disease trajectory over time.
Also, they found some features of the scoring system traditionally thought to be associated with more aggressive disease (e.g., the presence of crescent-shaped lesions in biopsy samples) were not as significant predictors of aggressive disease as previously thought.
These various insights should help doctors provide individual patients with more accurate estimates of their disease progression moving forward, enabling them to plan for better treatment over time.
