[Usefulness of anti-neutrophil cytoplasmic antibodies, anti-proteinase 3 and anti-myeloperoxidase in management of small vessel vasculitis].

BACKGROUND

Analysis of usefulness of antineutrophil cytoplasmic antibodies (AN-CA) as a marker of clinical activity in small vessel vasculitis.

PATIENTS AND METHODS

33 patients, 10 patients with Wegener's granulomatosis (WG) and 23 with microscopic polyangiitis (MPA) and rapidly progressive glomerulonephritis type III (RPGN III). The clinic and serologic follow-up was accomplished every 3 months during an average of 19 (SD, 24) months (range 3-52 months. The serologic follow-up included the determination of ANCA by indirect immunofluorescence (IFI) and ELISA, as well as the serum level of C reactive protein (RCP).

RESULTS

At the time of diagnosis all patients were ANCA positive by IFI and ELISA. The seroconversion of ANCA from positive to negative was produced in 30/33 patients (90%). Twenty-six out of these 30 patients (87%) achieved the seroconversion within the first 6 months. During the follow-up 4 patients had a major relapse, all with positive ANCA. In 2 patients, one of each group, seroconversion from negative to positive was not associated with clinical relapse of vasculitis.

CONCLUSION

ANCA should be used in conjunction with other indices of disease activity in patients with small vessel vasculitis.