Determination of anti-cyclic citrullinated peptide antibodies in the sera of patients with juvenile idiopathic arthritis.

OBJECTIVE: Anti-cyclic citrullinated peptide (anti-CCP) antibodies have been found in sera of 76% of patients with rheumatoid arthritis (RA), mainly in rheumatoid factor (RF) positive patients, with a specificity of 96%. We evaluated the presence of anti-CCP antibodies in patients with juvenile idiopathic arthritis (JIA) and assessed the possibility of synthetic citrullinated peptides as antigenic determinants in JIA. METHODS: The presence of anti-CCP antibodies was determined using 3 synthetic citrullinated peptide variants and 2 commercial kits (Inova Diagnostics and Axis-Shield Diagnostics) optimized for detecting JIA-specific antibodies in serum by an ELISA based assay. We evaluated 66 patients with JIA (16 RF positive polyarthritis, 18 RF negative polyarthritis, 19 oligoarthritis, and 13 systemic arthritis). We also tested 9 adult RA patients, 34 patients with systemic lupus erythematosus (SLE), and 25 healthy persons as controls. RESULTS: Significant concentrations of anti-CCP antibodies were detected in the majority of RF positive JIA patients with polyarthritis. Using the 2 synthetic linear peptides, 12/16 (75%) were positive; 9/12 (75%) were positive with the Inova kit and 9/10 (90%) were positive with the Axis-Shield kit. However, utilizing the synthetic linear peptides, significant concentrations of anti-CCP antibodies were detected in 51/66 (77%) JIA patients, including 15/18 (83%) RF negative polyarthritis, 16/19 (84%) oligoarthritis, and 8/13 (62%) systemic arthritis patients. No healthy control showed elevated antibody levels. In contrast, 4/9 (44%) patients with adult RA and 2/6 (33%) with SLE had elevated anti-CCP levels. The synthetic cyclic variant cfc-1-cyc yielded significant anti-CCP levels for 13/14 (93%) patients with RF negative polyarthritis, 6/10 (60%) with oligoarthritis, and 3/7 (43%) with systemic arthritis, and 8/9 (88%) RF positive patients. No healthy control had increased anti-CCP levels. However, 4/9 (44%) adult RA and 9/34 (26%) SLE patients were found to have elevated anti-CCP levels. Using the Inova and Axis-Shield kits, much smaller percentages were found in the RF negative patients, with only 4/16 (25%) in the oligoarthritis and RF negative polyarthritis patients with the Inova kits and 0/25 (0%) by the Axis-Shield kits. The Inova kit revealed elevated anti-CCP antibodies in 5/9 (56%) adult RA patients and in 8/34 (24%) SLE patients. No healthy control had elevated anti-CCP antibodies. However, the Axis-Shield kits did not detect anti-CCP antibodies in adult RA (0/9) or SLE (0/34) patients. Moreover, 0/25 (0%) healthy individuals exhibited anti-CCP levels. The presence of anti-CCP antibodies correlated more frequently with the presence of RF. CONCLUSION: This study confirms the presence of anti-CCP antibodies in patients with JIA, especially those with RF positive polyarthritis, by all ELISA based methods. Use of synthetic peptides also revealed anti-CCP antibodies in a percentage of RF negative patients with polyarthritis, oligoarthritis, and systemic arthritis; there was a loss in specificity, but an increase in sensitivity. These results suggest that antibodies to these antigenic peptides may be markers for JIA, and indicate a possible role of citrulline-containing epitopes in the pathogenesis of JIA.

The decreasing prevalence of uveitis associated with juvenile rheumatoid arthritis: do NSAIDs play a role?

We studied the prevalence and characteristics of chronic uveitis in a population of children diagnosed with juvenile rheumatoid arthritis (JRA). Uveitis is one of the most important, potentially debilitating extra-articular manifestations of JRA and has been observed in as many as 20% of cases. The medical records of 230 patients diagnosed with JRA and treated at a tertiary care hospital ophthalmology clinic between 1992 and 2000 were retrospectively reviewed. Seventeen patients (7.4%) were found to have clinical features of uveitis. There was a preponderance of female patients (16/17) and pauciarticular disease (13/17). Only 12 of 17 were ANA positive. Six had uveitis at diagnosis. Patients who were receiving naproxen had less incidence of uveitis compared with those receiving other nonsteroidal antiinflammatory drugs. Despite a relatively low prevalence of uveitis, complications occurred in about 24% (4/17) of the patients, even with adequate treatment and close monitoring. The prevalence of uveitis in JRA seems to be decreasing and may be secondary to the increased use of naproxen. However, routine ophthalmologic screening should be continued in patients with JRA to avoid potential complications of chronic uveitis.

Cardiopulmonary exercise testing with pulmonary artery catheterization detects early pulmonary vasculature changes in patients with connective tissue diseases.

Pulmonary hypertension is a well-recognized complication of connective tissue diseases (CTD), with clinical symptoms typically limited to those with relatively advanced disease. The objective of this study was to identify patients with early pulmonary vasculature changes using cardiopulmonary exercise testing with pulmonary artery catheterization. Four patients with CTD and normal Doppler echocardiogram results identified as high risk for pulmonary hypertension on the basis of disease process underwent cardiopulmonary exercise testing with pulmonary artery catheterization. All patients had normal mean pulmonary artery pressures at rest (<25 mmHg), but exhibited an abnormal rise in mean pulmonary artery pressure with exercise. Cardiopulmonary exercise testing should be considered in patients at high risk for pulmonary hypertension to identify those individuals who may benefit from early therapeutic intervention.