Anti-CCP antibodies measured at disease onset help identify seronegative rheumatoid arthritis and predict radiological and functional outcome.

OBJECTIVE: Anti-cyclic citrullinated peptide (anti-CCP) antibodies have been identified as highly specific for rheumatoid arthritis (RA). Studies suggest an association with radiographic outcome. The aims of this study were to assess the diagnostic and prognostic utility of the second-generation anti-CCP(2) test in a large cohort of early RA patients compared with connective tissue disease (CTD) controls. METHODS: One hundred and eighty-two patients with RA and 121 patients with CTD were recruited. All RA patients had less than 24 months of symptoms and had CRP, rheumatoid factor (RF), HLA typing (SE) and anti-CCP(2) antibodies measured at baseline. Function was assessed using the Health Assessment Questionnaire (HAQ) and X-rays performed at 0, 12 and 24 months. RESULTS: The anti-CCP(2) antibody test demonstrated a specificity of 91% and sensitivity of 81% for RA when compared with controls. In RF-negative patients, specificity was 92% and sensitivity 60%. Baseline demographics of the RA cohort showed mean age 57 yr, mean symptom duration 7 months, 63% RF-positive patients, 72% SE-positive, 81% CCP-positive and 21% erosive. The only predictor of change in Larsen score from 0 to 24 months in the cohort was the presence of the shared epitope (P<0.05) and in the RF-negative subgroup it was CCP(2) antibody titre >100 (P<0.05). Baseline HAQ was the only significant predictor of HAQ at 24 months, but in the RF-negative subgroup CCP(2) antibody titre >100 predicted a poor functional response at 24 months (P<0.05). CONCLUSIONS: This study confirms the diagnostic utility of anti-CCP(2) antibodies in early RA, particularly in seronegative patients, in whom anti-CCP(2) positivity also conferred prognostic utility for radiographic and functional outcomes.

Serum MMP-3 and MMP-1 and progression of joint damage in early rheumatoid arthritis.

OBJECTIVE: Expression and activation of matrix metalloproteinases such as MMP-3 (stromelysin-1) and MMP-1 (collagenase-1) are increased in patients with rheumatoid arthritis (RA). Previous negative reports of their value as predictors of joint damage may be due to the lack of a large longitudinal study of early RA patients. This study evaluated their use in assessing early untreated patients with RA and predicting subsequent joint damage. METHODS: Ninety-eight patients with early untreated RA of less than 12 months duration and 20 normal controls had baseline serum samples tested with a double-antibody enzyme-linked immunosorbent assay for each of MMP-1 and MMP-3. The subsequent changes in Larsen score (DeltaLarsen) and Health Assessment Questionnaire (DeltaHAQ) over the first 12 months were recorded. RESULTS: Baseline serum levels of MMP-3 and MMP-1 correlated significantly with baseline C-reactive protein (CRP) (r=0.42 and 0.49, P<0.001), DeltaHAQ (r=0.32 and 0.30, P<0.01) and DeltaLarsen (r=0.23 and 0.32, P<0.05) respectively. Analysis of the group of patients with a normal CRP at presentation (n=21) showed correlation of the baseline MMP-3 and MMP-1 with the presence of erosive disease during the first 12 months (r=0.52 and 0.65 respectively, P<0.05). Logistic regression analysis, in the patients who were non-erosive at presentation, showed that the strongest correlation with progression in Larsen score was the baseline MMP-3 level (r=0.30, P=0.01). CONCLUSIONS: Baseline serum MMP-1 and MMP-3 levels correlate with disease activity and predict functional and radiographic outcome in early untreated RA. They may have a particular value in predicting the progression of erosive disease in patients who are not erosive at presentation.