ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODIES (ANCA)

CLINICAL UTILITY:

Wegener's granulomatosis is a form of small vessel vasculitis. Its major pathologic features are necrotizing granulomatous lesions, which most often affect the upper and lower airways, vasculitis, necrotizing glomerulonephritis and pulmonary capillaritis. The mortality of WG is mainly related to the occurrence of rapidly progressive kidney disease and severe lung hemorrhage. A rapid diagnosis is desirable, so that treatment with immunosupression can be initiated. It is also important to continue follow up on WG patients because of the tendency of the disease to relapse. The cytoplasmic pattern (C-ANCA) is detected in the majority of patients with active Wegener's granulomatosis (>90%) and is rarely found in other diseases. The pattern is usually produced by antibodies to proteinase-3 (PR3). The perinuclear pattern (P-ANCA) is observed in Wegener's granulomatosis and in idiopathic necrotizing and crescentic glomerulonephritis as well as in microscopic polyangiitis (also known as microscoping periarteritis) with glomerulonephritis. P-ANCA patterns have also been associated with a variety of other conditions. The pattern is commonly produced by antibodies to myeloperoxidase (MPO), but is also associated with other antibodies. C-ANCA and P-ANCA titers appear to be indicative of the disease severity and activity in some patients with Wegener's granulomatosis or microscopic polyangiitis. The clinical significance of the atypical staining patterns is uncertain. The patterns are produced by a variety of antibodies and have been found in a several different conditions including inflammatory bowel disease, autoimmune rheumatic diseases, and vasculitis.

METHOD DESCRIPTION:

Anti-Neutrophil Cytoplasmic Antibodies (ANCA) are detected in the laboratory by the indirect immunofluorescence technique.

REFERENCE RANGE:

Perinuclear (P-ANCA) - perinuclear staining of ethanol fixed neutrophils. (Cytoplasmic granules seen on formalin fixed neutrophils.) Cytoplasmic (C-ANCA) - fine granular cytoplasmic staining with pattern with central accentuation on ethanol fixed neutrophils. (Cytoplasmic granules seen on formalin fixed neutrophils.) Atypical patterns - Atypical perinuclear or cytoplasmic staining patterns may be observed on ethanol fixed neutrophils. (Typically minimal staining is seen on formalin fixed neutrophils).

SPECIMEN REQUIREMENTS:

1.0 ml of serum is required (0.5 ml minimum). Refrigerate or freeze.