[Comparison between immunofluorescence techniques and ELISA, using whole neutrophil extract and primary granules, for the detection of antineutrophil cytoplasma antibodies (ANCA)]. / Comparação entre as técnicas de imunofluorescência e ELISA com extrato total de neutrófilos e com grânulos primários para a detecção de anticorpos contra o citoplasma de neutrófilos (ANCA).

The detection of antineutrophil cytoplasmic antibodies is a very important tool for the diagnosis of systemic vasculitis. The specificity and sensitivity of these antibodies depends on the assay utilized for their detection. Therefore we have compared the immunofluorescence test (IF) with the ELISA using two different antigens: total neutrophil extract and isolated primary granules. Two patterns of fluorescence were detected by IF: the classic pattern was highly specific for Wegener's granulomatosis. In contrast the perinuclear staining correlated with renal vasculitis but was also observed in other diseases. However the IF test was unable to differentiate low-positive from atypical patterns. Such distinction could be achieved by ELISA. The use of ELISA with isolated primary granules is a good alternative for if since it has a good specificity, sensitivity and reproducibility, moreover it is a quantitative method.