All biological samples will be processed and analyzed in Vancouver at the Child and Family Research Institute and at the University of British Columbia. Detailed data will be collected in electronic format and include demographic variables, socioeconomic status, detailed clinical history & physical findings, anthropometric measures, and measures of disease activity. All data for systemic vasculitis patients will be directly entered at each site into a secure, online, web-based data entry system called REDCap which is managed through the data management centre at the University of British Columbia in Vancouver. All CNS vasculitis data will be entered into the Brainworks database which is managed by the data management team at the Hospital for Sick Kids in Toronto.