Proteinase 3 -ANCA

Antineutrophil cytoplasmic antibodies (ANCA) are a class of autoantibodies with varied specificities against particular proteins in the cytoplasmic granules of neutrophils and the lysosomes of monocytes. Indirect immunofluorescence microscopy and enzyme immunoassay have defined two types of ANCA patterns one causing cytoplasmic staining (C-ANCA) the other perinuclear staining (P-ANCA) [346]. Greater than 95% of C-ANCA antibiodies are anti-proteinase 3 antibodies (PR3-ANCA) and greater than 95% of P-ANCA antibiodies are anti-myeloperoxidase antibodies (MPO-ANCA) [347]. 

ANCA-4. Slot MC,Tervaert JW, Boomsma MM, Stegman CA Positive classic antineutrophil cytoplasmic antibody (C-ANCA) titer at stitch to azathioprine therapy assoiated with repapse I proteinase 3-related vasculitis. Arthritis Rheum 51 269-273. 

Note that Wegener s granulomatosis limited to the upper respiratory tract has a lower frequency of ANCA (approximately 70%) compared to systemic disease, and Churg-Strauss syndrome with systemic vasculitis and glomerulonephritis has a higher frequency of ANCA than Churg-Strauss syndrome without glomerulonephritis. Abbreviations. ANCA, antineutrophil cytoplasmic autoantibodies MPO, myeloperoxidase PR3, proteinase 3. 

Schreiber A, Luft FC, Kettritz R. Membrane proteinase 3 expression and ANCA-induced neutrophil activation. Kidney Int 2004 65(6) 2172-2183. 

Although CSS belongs to the pulmonary ANCA-associated vascuUtides, which also include Wegener granulomatosis and microscopic polyangiitis, ANCA are present in only about 40% of patients and consist in 80% to 90% of cases of perinuclear ANCA (P-ANCA) with a specificity for myeloperoxidase on ELISA (88,90,100,101). Cytoplasmic ANCA with proteinase 3 specificity on ELISA are very rare in CSS, as opposed to Wegener granulomatosis. 

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