Objective: To evaluate the clinical significance of antineutrophil cytoplasmic antibodies (ANCA) in patients with rheumatoid arthritis (RA), and especially in those with clinically suspected or histologically proven nephropathy.
Methods: A total of 246 RA patients with (n = 149) and without (n = 97) histologically proven (n = 99) or clinically suspected (n = 50) nephropathy were studied for the presence of ANCA by immunofluorescence and enzyme immunoassay.
Results: Perinuclear ANCA (pANCA) were found in 52 (21%) of the 246 patients. Patients with clinically suspected or histologically proven nephropathy were significantly more frequently positive for pANCA (30% versus 7%; P < 0.00005) and had significantly higher mean (+/- SD) pANCA log titers (103 +/- 5.6 versus 27 +/- 3.0; P = 0.0011) than patients without clinically evident renal disease. Positivity for pANCA was associated with clinical and laboratory findings indicating severe basic disease and increased inflammatory activity. Irrespective of this association, pANCA acted as a significant and independent predictor of RA-associated nephropathy.
Conclusion: Perinuclear ANCA in RA indicate severe disease with increased inflammatory activity. There is an especially strong and independent association between pANCA and RA-associated nephropathy.