Relationship between anti-neutrophil cytoplasmic antibody determined with conventional binding and the capture assay, and long-term clinical course in vasculitis

• Objectives. To evaluate the relationship between anti-neutrophil cytoplasmic antibody (ANCA) measured with two different methods and long-term clinical course in vasculitis. Design. Retrospective determination of ANCA with two different assays for detection of PR3-ANCA, conventional direct binding ELISA and capture ELISA using monoclonal antibodies against PR3. The 245 ANCA determinations were performed from frozen blood samples collected three to four times a year in each patient. Setting. Department of Nephrology at a Swedish University Hospital. Subjects. A total of 10 ANCA-positive patients with vasculitis caused by Wegener's granulomatosis (WG) or microscopic polyarteritis (MPA) and a very long follow-up time (mean 9 years, range 5-15.5 years). Results. The total number of episodes with active vasculitis was 29 and all of them (100%) were detected by the capture technique whilst the conventional technique detected 23 (79%). The mean number of episodes with active disease requiring treatment with steroids and cytotoxic drugs was three per patient (range 1-6). At the time of clinical relapse of the vasculitis disease. the ANCA titre using the capture technique was either increasing or showed a very high value in all cases. The pattern of capture ANCA response could be subdivided into three categories: a close (four patients), an intermediate (three patients), and no (three patients) relationship between capture ANCA level and long-term clinical course. Conclusion. Detection of PR3-ANCA by the capture ELISA showed a higher sensitivity than that obtained by the direct ELISA in diagnosing relapse during follow-up of patients with vasculitis. The specificity of the capture ANCA was, however, low. as high levels occurred in patients without clinical disease activity.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Urologi och njurmedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Urology and Nephrology (hsv//eng)

Nyckelord

renal disease

proteinase 3

anti-neutrophil cytoplasmic antibody

microscopic polyarteritis

Wegener's granulomatosis

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)