The purpose of the clinical core is to provide pathologic data, clinical information and blood and tissue samples on ANCA glomerulonephritis (ANCA-GN) patients for three of the five proposed projects. The clinical core consists of five components that already exist and that have an ongoing establish and interconnected working relationship. The five components include 1) the UNC Nephropathology Laboratory, 2) the UNC Glomerulonephritis and Vasculitis 5) a statistician/epidemiologist. Working together, the components of this core have established the ability to public abstracts and manuscripts. The UNC Nephropathology Laboratory evaluates approximately 1,500 renal biopsy specimens per year with approximately 15% from the UNCS Glomerulonephritis have joined together with Drs. Ronald J. Falk and J. Charles Jeanette of UNC to form a research collaboration called the GDCN. The mainstay of the GDCN has been the maintenance an ANCA- GN patient registry. Clinical information is collected on over 250 patients diagnosed since 1986. Registry patients are followed from the onset of symptoms until death. Registry data has provided information for manuscripts on clinical presentation, disease associations, treatment response, environmental associations, and on prognostic markers for dialysis, death and disease relapses. The core will identify patients for participation in the Environmental Factors in ANCA-GN study (Project #5) and will maintain long-term follow-up of these patients to evaluate the role of environmental factors in disease progression. The registry provides a pool of patients for collecting blood samples. Samples can be collected at the UNC Glomerulonephritis and Vasculitis Clinic and from the GDCN practices for collecting blood samples. Samples can be collected at the UNC Glomerulonephritis and Vasculitis Clinic and from the GDCN practices. Blood samples will be needed on numerous patients during various stages of Vitro Analysis of ANCA- Induced Glomerular Inflammation (Project 3). In summary, the core will play a critical role in identifying patients and obtaining blood samples and clinical information at these various clinical stages of the disease. The core will also provide support for statistical analysis. The core has demonstrated the ability to work collaboratively and can meet the clinical research needs of the program project.