ANCA-positive and ANCA-negative granulomatosis with polyangiitis

Aim

To compare the clinical manifestations and outcomes of ANCA-positive and ANCA-negative granulomatosis with polyangiitis (GPA)

Material and methods

One hundred twelve GPA patients were enrolled in a retrospective study. Anti-neutrophil cytoplasmic antibodies (ANCA) were determined by antigen-specific ELISA. Fifty nine patients tested positive for ANCA against proteinase-3 (PR3), 17 patients for ANCA against myeloperoxidase (MPO), and 4 patients for both types of autoantibodies, where as ANCA were not detected in 32patients. Median duration of follow-up was 75.5 [45;124] months. We calculated the Birmingham Vasculitis Activity Score (BVAS) at diagnosis and the Vasculitis Damage Index (VDI) at the end of follow-up.

Results

Patients with ANCA-positive and ANCA-negative GPA were similar in age and gender. Localized GPA in ANCA-negative patients occurred more frequently than in ANCA-positive patients (59.4% and 11.3%, respectively;p<0.00001). Orbital pseudotumor was the most common manifestation of the localized GPA in ANCA-negative patients. ANCA-positive patients compared with ANCA-negative patients presented more frequently with respiratorytract disease (97.5% vs. 68.0%), pulmonary involvement (77.2% vs. 31.3%), and kidney disease (67.5% vs. 15.6%, allp⩽0.00001). Rapidly progressive glomerulonephritis and diffuse alveolar hemorrhage occurred almost exclusively in ANCA-positive patients (p<0.01), partly explaining a higherrate of cyclophosphamide administration for remission infuction in this group of patients (87.5%, p<0.0001). The frequency of constitutional symptoms, arthritis, skin and nervoussystem disease was similar in ANCA-positive and ANCA-negative patients. Median BVAS at diagnosis and VDI at the end of follow-up were significantly higher in ANCA-positive patients than in ANCA-negative patients (p<0.00001). Therelapse rate withing one year after achievement of remission was similar in two groups of patients. The difference in survival between ANCA-positive and ANCA-negative patients did not reach statistical significance.

Conclusion

ANCA-negative GPA is associated with the localized form of disease and a lower frequency of lung and kidney involvement, where as the relapse rates were similar in ANCA-positive and ANCA-negative patients.

Key words

ANCA-associated vasculitis, granulomatosis with polyangiitis, ANCA