Determining Disease Activity Biomarkers in Individuals With Polyarteritis Nodosa

PAN, also known as systemic necrotic vasculitis, was the first recognized form of primary systemic vasculitis. PAN causes the inflammation of small- to medium-sized blood vessels, especially those supplying the nerves, skin, kidneys, gastrointestinal tract, heart, eye, and genitals. Unlike another form of vasculitis called microscopic polyangiitis, PAN does not usually cause glomerulonephritis, a type of kidney disease, or vasculitis in the very smallest blood vessels (arterioles, capillaries, and venules). There are no radiographic or serologic tests that can reliably measure disease activity in PAN. Currently, clinicians must rely on patients' symptoms, signs, laboratory tests, and imaging to guide treatment decisions, but such data are rarely consistently reliable in determining PAN disease activity. This study will use new scientific methods to discover new biomarkers that can be used to monitor disease activity in PAN patients. These biomarkers may be used to help direct clinical care for PAN patients and assist in future drug development. Study visits will occur monthly for the first year, then every 3 months thereafter for the remainder of the study. Blood and urine collection will occur at every visit. A physical exam and medical and medication history will occur every 3 months; also, participants will be asked to complete several questionnaires to assess disease activity, health status, and tobacco, alcohol, and drug use. Participants may have additional study visits if a disease flare or disease-related complications occur during the study.