Limited prognostic value of changes in antineutrophil cytoplasmic antibody titer in patients with Wegener's 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.