AAV often damages the kidneys (AAGN), leading to kidney failure in about one quarter of patients, even with our best treatments. Poor understanding of the causes of the different kinds of kidney damage seen in AAGN has kept us from finding better treatments. Our study uses cutting edge genetic technologies to better understand the root causes of the kidney damage we see in AAGN. We have previously looked at genetic expression of kidney tissue in AAGN which provided evidence that immune cells play an important role. In this project, we will look at proteins from the urine of patients with AAGN to see which proteins are associated with inflammation occurring in the kidney and the risk of end stage kidney disease (Aim 1). This is an important first step to finding proteins that can predict kidney disease relapse. We will also look at the kidney’s immune cells from adults and children in more detail and see which ones are associated with the different kinds of tissue changes we see occurring in the kidney (Aim 2). This work will lead to better and more individualized treatments for patients with AAGN.