Nomenclature of Vasculitides: 2012 Revised International Chapel Hill Consensus Conference

Abstract

A nomenclature system provides names and definitions for diseases, and provides the framework for establishing classification criteria for groups of patients and diagnostic criteria for individual patients. The International Chapel Hill Consensus Conference Nomenclature of Vasculitides (CHCC) provides standardized names and definitions for different classes of vasculitis, but does not provide validated criteria for classifying cohorts of patients into these classes, or for diagnosing (classifying) an individual patient. The CHCC nomenclature and definitions are useful for communication among health care providers, understanding the medical literature, guiding development of classification and diagnostic criteria, and facilitating research on cohorts of patients with vasculitis. Names and definitions evolve more slowly than classification and diagnostic criteria because the latter must change as new diagnostic technologies and clinical laboratory testing are available. For example, the discovery of anti-neutrophil cytoplasmic autoantibodies (ANCA) added a new criterion for classifying vasculitis. The most robust ongoing effort to develop classification and diagnostic criteria for vasculitis is by the Diagnostic and Classification Criteria for Vasculitis (DCVAS) study group. Once data are collected from large vasculitis patient cohorts, identifying the most clinically and biologically relevant classes, and the most accurate and precise diagnostic criteria, may require the application of supervised and unsupervised machine learning algorithms. It will be interesting to see how machine generated vasculitis classes agree (or not) with the CHCC classes that were devised by mere mortals.