Study identifies initial cellular events in autoimmune kidney inflammation

When immunity works well, the body steers clear of infection and disease. However, when the immune system goes awry, healthy cells can often end up in the firing line. This can occur in autoimmune diseases like anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, a kidney disease in which ANCAs trigger destructive inflammation. However, there has been little information about the sequence of events associated with the early stages of disease.

Now, researchers from the University of Osaka have uncovered the first steps in the development of ANCA-associated glomerulonephritis. The researchers found that injured kidney cells send signals that attract immune cells, including neutrophils, which drive the spread of inflammation in the early stages. The findings were published this month in the Journal of Experimental Medicine.

Despite improvement in treatment options, current treatments for ANCA-associated glomerulonephritis carry risks ranging from side effects of prolonged use to treatment failure. Targeted treatments could offer better health outcomes for patients. However, to do so, researchers would need to clarify how the disease process starts to tackle the problems head on.

In ANCA-associated glomerulonephritis, the kidneys are frequently involved. This makes it an excellent candidate for studying the initial steps of the autoimmune disease process."

Masayuki Nishide, lead author

The researchers compared kidney samples from healthy donors and from patients with ANCA-associated glomerulonephritis who did not receive treatment. Using cutting-edge technology, they studied the sequence of events in disease progression while preserving cellular organization in the tissue samples.

"Our goal was to investigate how exactly the disease unfolds in the early stage so that we could attempt to stop it before significant damage is done," says senior author, Atsushi Kumanogoh. "We were surprised to see that despite the normal appearance of the tissue, we could still detect changes at the cellular level."

After finding that diseased organs displayed more damage compared to normal kidneys, the researchers aimed to replicate and treat the injury using a mouse model. The researchers found that excessive neutrophil activation is a key aspect of early disease, leading researchers to attempt to decrease neutrophil activation. In turn, researchers modified antibodies and tested whether they could minimize stimulation of Fcγ receptors, which are integral to the development of the inflammatory process.

The results were promising, and the modified antibodies successfully reduced kidney injury in the model. These findings point to a potential new therapeutic strategy aimed at stopping the disease at its earliest stage, before severe kidney damage develops. It is hoped that continued developments in this area can offer patients new hope for potentially safer treatments with fewer side effects.