Immediate determination of ACPA and rheumatoid factor--a novel point of care test for detection of anti-MCV antibodies and rheumatoid factor using a lateral-flow immunoassay.
BACKGROUND
Autoantibodies against mutated and citrullinated vimentin (MCV) represent a novel diagnostic marker for rheumatoid arthritis (RA). Recently, an increased sensitivity for anti-MCV compared to autoantibodies against cyclic citrullinated peptides (anti-CCP2) was shown in cohorts of patients with early RA and established disease.The aim of this study was to develop and evaluate a point of care test (POCT) for detection of anti-MCV antibodies immediately at the first visit or at the bed side.


METHODS
A lateral-flow immunoassay was developed for simultaneous detection of anti-MCV antibodies and rheumatoid factor (RF-IgG) and evaluated in a prospective setting. Analyses were performed from whole blood samples of patients with seropositive RA (n=108), seronegative RA as well as other rheumatic disorders (n=122), and healthy blood donors (n=200) and compared to detection via ELISA.


RESULTS
Using the POCT, anti-MCV antibodies were detected in 54.6% and RF-IgG in 56.5% of patients with RA. Specificity was 99.1% for anti-MCV antibodies and 91.2% for RF-IgG. Compared to ELISA's results, POCT sensitivity was 69.3% for anti-MCV and 55.6% for RF-IgG, specificity was 99.7% and 97.2%, respectively.


CONCLUSIONS
This POCT for detection of anti-MCV antibodies and RF-IgG provides high specificity for the diagnosis of RA and is useful in clinical practice due to its simplicity and its reliable performance. This test can greatly improve a timely management of RA and may help in screening patients with suspected RA in non-specialized settings prompting early referrals.
Renger
Franziska
F
Department of Rheumatology and Clinical Immunology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany. franziska.renger@charite.de
Bang
Holger
H
Feist
Eugen
E
Fredenhagen
Gert
G
Natusch
Alexander
A
Backhaus
Marina
M
Burmester
Gerd-R
GR
Egerer
Karl
K
D000328:Adult; D000368:Aged; D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology; D019095:Point-of-Care Systems; D012217:Rheumatoid Factor / Q000097:blood*; D012680:Sensitivity and Specificity; D014746:Vimentin / Q000276:immunology*
D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D010456:Peptides, Cyclic; D014746:Vimentin; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor