Are antineutrophil cytoplasmic antibodies a marker predictive of relapse in Wegener's granulomatosis? A prospective study.

Objectives: To investigate the predictive value of testing for antineutrophil cytoplasmic antibodies (ANCA) in 55 patients with systemic Wegener's granulomatosis (WG) included in a randomized, prospective trial comparing corticosteroids and oral or pulse cyclophosphamide.

Methods: All 55 patients received corticosteroids. A cyclophosphamide pulse of 0.7 g/m2 was given at the time of diagnosis. After the first pulse, the patients were assigned at random to receive either pulse or oral cyclophosphamide (2 mg/kg/day), independently of ANCA results. ANCA were sought using an immunofluorescence assay and an attempt was made to correlate them with relapse of WG. ANCA were monitored throughout the study.

Results: At the time of diagnosis, ANCA were detected in 48 (87%) patients, with a cytoplasmic labelling pattern in 44 and a perinuclear pattern in four. ANCA follow-up was available for 50 patients. ANCA disappeared in 34 patients and persisted in nine. For 79% of the patients, the clinical course improved with the disappearance of ANCA and deteriorated with their persistence or increased titre. Among the patients who were initially ANCA-positive, 23 relapses occurred. Relapses were more frequent when ANCA remained positive or reappeared [13/19 ANCA-positive patients vs 3/29 ANCA-negative patients (P<0.01)]. Nine relapses (39%) occurred in patients with persistent ANCA, and ANCA reappearance preceded relapse in eight (35%). The mean time between inclusion and relapse did not differ between the patients who became ANCA-negative and those who were persistently ANCA-positive (14.6+/-13.2 vs 14.4+/-8.2 months). The mean time to ANCA disappearance was similar for the patients who relapsed and those who did not. Corticosteroids and pulse or oral cyclophosphamide did not significantly modify the time to ANCA disappearance. Throughout the study, seven patients were ANCA-negative.

Conclusion: Although ANCA positivity was associated with relapse, discordance between cytoplasmic ANCA and disease activity was not unusual. In the absence of clinical manifestations, ANCA titres alone can serve as a warning signal but not indicate whether to adjust or initiate treatment.