Prognosis of Wegener's granulomatosis limited to the respiratory tract: Significance of c-ANCA

Purpose: Cytoplasmic staining anti-neutrophil cytoplasmic antibodies (c-ANCA) are a specific marker for Wegener's granulomatosis (WG). The sensitivThis study was designed to determine whether the presence or absence of c-ANCA is a prognostic indicator in the latter group of patients. Methods: Patients with biopsy proven WG limited to the respiratory tract who had an ANCA-test performed at initial presentation and for whom at least 5 years of follow-up data were available were included. Patients with signs of systemic vasculitis were excluded. C-ANCA negative patients who were on treatment at the time of their first c-ANCA test were also excluded, because the negative test result might have been a result of the therapy. The clinical course of the patients during the 5 years of follow-up was evaluated by review of the clinical records and questionnaires to patients and their local physicians. Differences between groups were analyzed by Fisher's exact test. Results: 1 of 6 patients in the c-ANCA negative group (17%) developed generalized disease (renal involvement) after 4.5 years, accompanied by the appearance of c-ANCA. 5 of 16 patients in the c-ANCA positive group (31%) developed renal involvement. This difference between the groups was not statistically significant (p=0.63). One patient in the c-ANCA positive group died of the disease. No clear relation was detected between initial organ involvement, initial therapy and subsequent progression to generalized disease. 2 of 6 c-ANCA negative patients (33%) required immunosuppressive therapy (1 because of sulfa allergy, 1 when he developed renal disease). In contrast, 15 of 16 c-ANCA positive patients (94%) required immunosuppressive therapy for control of disease activity during the observation period (p=0.009). Conclusions: The overall prognosis of WG limited to the respiratory tract is good. Progression to generalized disease does not occur in the absence of c-ANCA. The initial absence of c-ANCA does not exclude the possibility of later seroconversion and progression to generalized disease. C-ANCA negative WG limited to the respiratory tract appears to have a more benign clinical course and can be successfully treated with trimethoprim-sulfamethoxazole alone. Clinical Implications: The absence of c-ANCA appears to be a good prognostic indicator in WG limited to the respiratory tract.