Background Antineutrophil cytoplasmic antibodies (ANCAs) have been suggested to occur in rheumatoid arthritis (RA), especially in patients with severe and longstanding disease. However in some studies no association was found between disease activity and ANCAs.
Objectives To determine the occurrence of ANCAs in patients with RA and compare the clinical and laboratory activity parameters between ANCAs positivity and negativity.
Methods Sera from 85 patients (mean age 50.5 years, 67 women and 18 men) with RA were included in study. Morning stiffness duration, pain intensity (Visual Analogue Scale), fatigue, tender and swollen joint counts (28 joints), systemic symptoms, patients and physicians general health assessment (Visual Analogue Scale), disease activity (DAS28), functional status (ACR) and disability (Health Assessment Questionnaire) were assessed of all patients.
Besides the routine laboratory activity parameters, ANCA testing was performed by standard indirect immunofluorescence. Antibody against the cytoplasmic antigens proteinase-3 (PR3) and myeloperoxidase (MPO) were measured by enzyme-linked immunosorbent assay.
Results ANCAs were found in 15 (17.6%) of patients with RA; 9 with atypical ANCA, 5 with perinuclear ANCA and 1 with cytoplasmic ANCA. Five of these 15 patients had vasculitis. None of the patients had Feltys syndrome, neutropenia or renal involvement. 4/5 patients with perinuclear ANCA and 1/9 patients with atypical ANCA had positive test result for MPO. None of the patients had PR3.
There were no significant differences in ANCA positivity with respect to the duration of disease (mean 8.7 years), age, gender, clinical and laboratory inflammatory parameters except for the duration of morning stiffness (p = 0.04) and antinuclear antibody positivity (p = 0.001).
Conclusion We observed that perinuclear ANCA pattern is specific for MPO but perinuclear and atypical ANCAs may not be associated with vasculitis in the presence of RA. Clinical significance of positive ANCAs was not justified with the findings of the study, as the number of patients with positive ANCA was few.
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