USEFUL OF ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES, ANTIPROTEINASE-3 ANDANTIMYELOPEROXIDASE IN MANAGEMENT OF SMALL VESSEL VASCULITIS

BACKGROUND: Analysis of usefulness of antineutrophil cytoplasmic antib odies (AN-CA) as a marker of clinical activity in small vessel vasculi tis. PATIENTS AND METHODS: 33 patients, 10 patients with Wegener's gra nulomatosis (WC;) and 23 with microscopic polyangiitis (MPA) and rapid ly progressive glomerulonephritis type III (RPGN III) The clinic and s erologic followup was accomplished every 3 months during an average of 19 (SD,24) months (range 3-52 months). The serologic follow-up includ ed the determination of ANCA by indirect immunofluorescence (IR) and E LISA, 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 E LISA. The seroconversion of ANCA from positive to negative was produce d in 30/33 patients (90%). Twenty-six out of these 30 patients (87%) a chieved the seroconversion within the first 6 months, During the follo w up 4 patients had a major relapse, all with positive ANCA. In 2 pati ents, one of each group, seroconversion from negative to positive was not associated with clinical relapse of vasculitis, CONCLUSION: ANCA s hould be used in conjunction with other indices of disease activity in patients with small vessel vasculitis.