Diagnostic value of anti-human citrullinated fibrinogen ELISA and comparison with four other anti-citrullinated protein assays.
We studied the diagnostic performance of the anti-human citrullinated fibrinogen antibody (AhFibA) ELISA for rheumatoid arthritis (RA) in a consecutive cohort (population 1) and evaluated the agreement between the AhFibA ELISA and four other assays for anti-citrullinated protein/peptide antibodies (ACPAs) as well as rheumatoid factor in patients with longstanding RA (population 2). Population 1 consisted of 1024 patients with rheumatic symptoms; serum samples from these patients were sent to our laboratory for ACPA testing within the context of a diagnostic investigation for RA. Ninety-two of these patients were classified as having RA according to the American College of Rheumatology criteria and 463 were classified as non-RA patients. Population 2 consisted of 180 patients with longstanding RA and was used to assess agreement and correlations between five ACPA assays: anti-cyclic citrullinated peptide (CCP)1 and anti-CCP2 antibodies were detected using a commercially available ELISA, AhFibA using ELISA, and anti-PepA and anti-PepB antibodies using line immunoassay. Applying previously proposed cut-offs for AhFibA, we obtained a sensitivity of 60.9% and a specificity of 98.7% in population 1. Receiver operating characteristic curve analysis could not detect a significant difference in diagnostic performance between the AhFibA ELISA and anti-CCP2 assay. Performing a hierarchical nearest neighborhood cluster analysis of the five different ACPA assays in population 2, we identified two clusters: a cluster of anti-pepA, anti-pepB and anti-CCP1, and a cluster of AhFibA and anti-CCP2. In conclusion, we found that AhFibA and anti-CCP2 antibodies had similar diagnostic performance. However, disagreement between ACPA tests may occur.
Vander Cruyssen
Bert
B
Department of Rheumatology, Ghent University Hospital, Ghent, Belgium. Bert.VanderCruyssen@Ugent.be
Cantaert
Tineke
T
Nogueira
Leonor
L
Clavel
Cyril
C
De Rycke
Leen
L
Dendoven
Amélie
A
Sebag
Mireille
M
Deforce
Dieter
D
Vincent
Christian
C
Elewaut
Dirk
D
Serre
Guy
G
De Keyser
Filip
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood*; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis*; D002648:Child; D002956:Citrulline / Q000276:immunology*; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D005260:Female; D005340:Fibrinogen / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology; D020033:Protein Isoforms / Q000276:immunology; D012216:Rheumatic Diseases / Q000097:blood / Q000175:diagnosis; D012217:Rheumatoid Factor / Q000097:blood
D000906:Antibodies; D010456:Peptides, Cyclic; D020033:Protein Isoforms; C487763:cyclic citrullinated peptide; D002956:Citrulline; D005340:Fibrinogen; D012217:Rheumatoid Factor