LIMITED PROGNOSTIC VALUE OF CHANGES IN ANTINEUTROPHIL CYTOPLASMIC ANTIBODY TITER IN PATIENTS WITH WEGENER GRANULOMATOSIS

Objective. To assess the correlation and prognostic value of antineutrophil cytoplasmic antibody (cANCA) titers with disease activity in patients with Wegener's granulomatosis (WG). Methods. One hundred six patients with WG had serum ANCA determinations; 72 had serial titers obtained routinely at 1-3-month intervals. One hundred twelve subjects (19 of whom were healthy donors) served as controls. All serum samples were tested for cANCA by an indirect immunofluorescence technique. A prospective analysis of disease activity and cANCA values was performed. Disease activity was assessed according to clinical, laboratory, radiographic, and histopathologic findings. Results. Positivity for cANCA was a sensitive (88%) marker of active WG. However, changes in serial titers, temporally correlated with a change in disease status in only 64% of patients. Furthermore, an increase in the cANCA titer preceded clinical exacerbation of disease in only 24% of patients who had been in remission or had low-grade, smoldering disease. Conclusion. A rise in cANCA titer alone should not be considered adequate evidence of an impending clinical exacerbation, and therefore does not justify initiating or increasing immunosuppressive therapy.