Autoantibodies in Systemic Vasculitis

Systemic vasculitis is a heterogeneous group of disorders characterized by inflammation andnecrosis in the vessel wall. The diagnosis of a systemic vasculitis is challenging, because patients usually present a broad spectrum of manifestations that vary according to the predominant size of vessels affected, organs and systems involved, and the extent of the inflammatory process (1). In systemic vasculitis, disease manifestations usually cluster into clinical phenotypes and definite diagnosis rely on confirmation by tissue biopsy, angiography, or by serologic tests. However, when a systemic vasculitis is under investigation, it is of paramount importance to keep in mind vasculitis mimics (e.g., genetic vascular disorders and atheroembolic diseases) and secondary causes (i.e., infections, malignancy, connective tissue disorders, or drugs) (2). The main serologic tests for the diagnosis of primary systemic vasculitides are antineutrophil cytoplasmic antibodies (ANCA), cryoglobulins, anti-glomerular basement membrane (anti-GBM) antibodies, and anti-C1q antibodies (3). Although, several other autoantibodies have been investigated in systemic vasculitis, the clinical usefulness of these antibodies still needs further investigation (1, 2) (Table 1). Herein, themain autoantibodies and their clinical associations in systemic vasculitis are reviewed.