Specimen Information

Type

Gold, SST

Volume

1.0 ml

Transport Info

Refrigerated

Fasting Required?

False

Clinical Significance

Diagnosis and follow-up of Wegener’s Granulomatosis (WG)
Evaluation of patients suspected of having systemic vasculitis, especially patients with renal disease or unexplained multi-organ disease possibly due to vasculitis
Three types of Anti-Neutrophil Cytoplasmic Antibody (ANCA) patterns are detectable using standard immunofluorescent methodology. The classic ANCA pattern appears as a diffuse granular cytoplasmic fluorescence and is specific for antibodies vs. serine protease 3 (PR-3). This pattern, characteristic of Wegener’s granulomatosis and to a lesser extent microscopic polyarteritis, has been designated c-ANCA. A second ANCA pattern has been described that appears as perinuclear neutrophilic stain and has been designated pANCA. The p-ANCA pattern is specific for other neutrophilic enzymes, including myeloperoxidase (MPO), elastase, and lactoferrin. The most common target antigen associated with pANCA is myeloperoxidase. pANCA is seen in association with a more organ-limited vasculitis, in particular pauci-immune necrotizing glomerulonephritis. pANCA is typically not seen in systemic vasculitis. A third type of ANCA pattern, called Atypical ANCA (a-ANCA), occurs when the initially positive p-ANCA cannot be confirmed on formalin-fixed slides and the ANA is negative. This has been described in ulcerative colitis and ascending cholangitis.In patients with active generalized Wegener’s granulomatosis (WG), the frequency of positive cANCA results (sensitivity) is approximately 85-90%. A negative test of c-ANCA does not completely rule out WG. In addition, positive c-ANCA results and antibodies to PR-3 can also be seen in polyarteritis nodosa. In patients with documented WG, rising titers of c-ANCA suggest relapse and falling titers suggest response to therapy. In patients with active renal disease, a positive p-ANCA result suggests the presence of antibodies to MPO and pauci-immune necrotizing glomerulonephritis. However, positive p-ANCA results are not specific for anti-MPO antibodies. Positive ANCA results (p-ANCA and, rarely, c-ANCA) may occur in patients with diseases other than WG or vasculitis, including Goodpasture’s syndrome, lupus erythematosus, rheumatoid arthritis, and Sjogren’s Syndrome.