Vasculitis

Diagnostics for ANCA associated vasculitis (AAV) are primarily based upon immunofluorescence (IFA). Standard for IFA is a BIOCHIP of ethanol and formaldehyde fixed human granulocytes. However, special EUROIMMUN BIOCHIPs (e.g. HEp2 cells) also play a significant role in increasing the diagnostic certainty. Our technique integrates conventional cell culture substrates with defined single antigens on one test field. This makes it easy to interpret different immunofluorescence patterns and thus increases the diagnostic value.

On immunofluorescence, two types of ANCA are recognized:

• Cytoplasmic type (cANCA) which is directed against proteinase 3 (PR3)
• And perineural type (pANCA) which is indicative of a spectrum of diseases.

The main target antigens for pANCA are myeloperoxidases (found in the cytoplasmic granules of myelocytes). However, granulocyte elastase, lactoferrin, cathapsin and lyzozyme etc. also act as potential target antigens.

All diagnostics for anti-PR3 and anti-MPOs should be confirmed with monospecific test such as ELISA/ChLIA. Moreover, most of the times, the antibodies are not detected on ELISA. Hence, sensitivity and specificity of the tests shoulder over parallel performance of both IFA and ELISA.