A comparison of the frequency of antibodies to cyclic citrullinated peptides using a third generation anti-CCP assay (CCP3) in systemic sclerosis, primary biliary cirrhosis and rheumatoid arthritis.
The objective was to investigate the frequency of anti-cyclic citrullinated peptides (CCP) antibodies in systemic sclerosis (SSc) and primary biliary cirrhosis (PBC), utilizing a new "third generation" anti-CCP ELISA (anti-CCP3) kit and a conventional anti-CCP2 assay. Patients with PBC, SSc, RA, and normal controls were included in the study. Serum samples were screened for autoantibodies by indirect immunofluorescence (IIF), antibodies to CCP by a second- and third-generation ELISA, antibodies to "scleroderma" antigens (CENP B, Scl-70, PM/Scl and fibrillarin-Scl-34) by a line immunoassay (LIA), and IgM RF by ELISA. The frequency of anti-CCP2 antibodies in SSc and PBC samples was 14.8% (11/74) and 6.2% (5/80), respectively, and the frequency of anti-CCP3 antibodies in SSc was 13.5% (10/74) and in PBC was 3.7% (3/80). By comparison, in the RA group the frequency of anti-CCP3 and anti-CCP2 antibodies was 79.1% (38/48) and 77% (37/48), respectively. Anti-CCP3 ELISA had a sensitivity, specificity, and positive and negative likelihood ratios (LR) of 79% (95% confidence interval [CI] = 64-89%), 93% (95% CI = 88-96%), 11.8 (95% CI = 6.8-20.3), and 0.22 (95% CI = 0.12-0.38), respectively. By comparison, the anti-CCP2 assay had a sensitivity, specificity, and positive and negative LRs of 77% (95% CI = 62-87), 90% (95% CI = 85-94), 8.3 (95% CI = 5.2-13.2), and 0.25 (95% CI = 0.15-0.42), respectively. In patients with SSc, there was an association of anti-CCP2 antibodies with the presence of arthritis, but there was no association of anti-CCP2 or anti-CCP3 with anti-CENP B, anti-Scl 70, or RF. This study confirmed the high specificity and sensitivity of both anti-CCP assays for the diagnosis of RA. The presence of anti-CCP antibodies in SSc was only correlated with the presence of arthritis.
Santiago
Mittermayer
M
Servico de Reumatologia do Hospital do Santa Izabel, Escola Bahiana de Medicina e Saude Publica, Salvador, Brazil.
Baron
Murray
M
Miyachi
Kiyomitsu
K
Fritzler
Marvin J
MJ
Abu-Hakima
M
M
Leclercq
S
S
Bell
M
M
Hudson
M
M
Mathieu
J-P
JP
Taillefer
S
S
Jones
N
N
Docherty
P
P
Khraishi
M
M
Markland
J
J
Pope
J
J
Robinson
D
D
Smith
D
D
Sutton
E
E
D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000175:diagnosis / Q000276:immunology*
D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide