The number of elevated cytokines and chemokines in preclinical seropositive rheumatoid arthritis predicts time to diagnosis in an age-dependent manner.
OBJECTIVE
To evaluate levels of biomarkers in preclinical rheumatoid arthritis (RA) and to use elevated biomarkers to develop a model for the prediction of time to future diagnosis of seropositive RA.


METHODS
Stored samples obtained from 73 military cases with seropositive RA prior to RA diagnosis and from controls (mean 2.9 samples per case; samples collected a mean of 6.6 years prior to diagnosis) were tested for rheumatoid factor (RF) isotypes, anti-cyclic citrullinated peptide (anti-CCP) antibodies, 14 cytokines and chemokines (by bead-based assay), and C-reactive protein (CRP).


RESULTS
Preclinical positivity for anti-CCP and/or ≥2 RF isotypes was >96% specific for future RA. In preclinical RA, levels of the following were positive in a significantly greater proportion of RA cases versus controls: interleukin-1α (IL-1α), IL-1β, IL-6, IL-10, IL-12p40, IL-12p70, IL-15, fibroblast growth factor 2, flt-3 ligand, tumor necrosis factor α, interferon-γ-inducible 10-kd protein, granulocyte-macrophage colony-stimulating factor, and CRP. Also, increasing numbers of elevated cytokines/chemokines were present in cases nearer to the time of diagnosis. RA patients who were ≥40 years old at diagnosis had a higher proportion of samples positive for cytokines/chemokines 5-10 years prior to diagnosis than did patients who were <40 years old at diagnosis (P < 0.01). In regression modeling using only case samples positive for autoantibodies highly specific for future RA, increasing numbers of cytokines/chemokines were predictive of decreased time to diagnosis, and the predicted time to diagnosis based on cytokines/chemokines was longer in older compared with younger cases.


CONCLUSIONS
Levels of autoantibodies, cytokines/chemokines, and CRP are elevated in the preclinical period of RA development. In preclinical autoantibody-positive cases, the number of elevated cytokines/chemokines is predictive of the time of diagnosis of future RA in an age-dependent manner.
Deane
Kevin D
KD
Division of Rheumatology, University of Colorado School of Medicine, Aurora, CO 80045, USA. Kevin.Deane@UCDenver.edu
O'Donnell
Colin I
CI
Hueber
Wolfgang
W
Majka
Darcy S
DS
Lazar
Ann A
AA
Derber
Lezlie A
LA
Gilliland
William R
WR
Edison
Jess D
JD
Norris
Jill M
JM
Robinson
William H
WH
Holers
V Michael
VM
D000328:Adult; D000367:Age Factors; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D018925:Chemokines / Q000097:blood*; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012217:Rheumatoid Factor / Q000097:blood; D018709:Statistics, Nonparametric; D013997:Time Factors
D001323:Autoantibodies; D015415:Biomarkers; D018925:Chemokines; D016207:Cytokines; D012217:Rheumatoid Factor