Abstract: Anti-neutrophil cytoplasrnic autoantibodies (ANCA) were first described in patients with necrotizing glomerulonephritis. The original observation passed virtually unnoticed until an association was found between ANCA and active Wegener's granulomatosis. Since then, tremendous progress has been made in elucidating the association between ANCA subtypes and clinicopathologic syndromes, and in considering potential pathogenic role of ANCA in vascular inflammation. The gold standard method for ANCA detection rests with indirect immunofluorescence (IIF) microscopy. ...