RT Journal Article
SR Electronic
T1 Prevalence of Anti-Peptidylarginine Deiminase Type 4 Antibodies in Rheumatoid Arthritis and Unaffected First-degree Relatives in Indigenous North American Populations
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 1523
OP 1528
DO 10.3899/jrheum.130293
VO 40
IS 9
A1 Elizabeth D. Ferucci
A1 Erika Darrah
A1 Irene Smolik
A1 Tammy L. Choromanski
A1 David B. Robinson
A1 Marianna M. Newkirk
A1 Marvin J. Fritzler
A1 Antony Rosen
A1 Hani S. El-Gabalawy
YR 2013
UL http://www.jrheum.org/content/40/9/1523.abstract
AB Objective. To determine whether anti-peptidylarginine deiminase type 4 (PAD4) antibodies were present in first-degree relatives (FDR) of patients with rheumatoid arthritis (RA) in 2 indigenous North American populations with high prevalence of RA. Methods. Participants were recruited from 2 indigenous populations in Canada and the United States, including patients with RA (probands), their unaffected FDR, and healthy unrelated controls. Sera were tested for the presence of anti-PAD4 antibodies, anticyclic citrullinated peptide (anti-CCP) antibodies, and rheumatoid factor (RF). HLA-DRB1 subtyping was performed and participants were classified according to number of shared-epitope alleles present. Results. Antibodies to PAD4 were detected in 24 of 82 (29.3%) probands; 2 of 147 (1.4%) relatives; and no controls (p < 0.0001). Anti-CCP was present in 39/144 (27.1%) of the relatives, and there was no overlap between positivity for anti-CCP and PAD4 in the relatives. In RA patients, anti-PAD4 antibodies were associated with disease duration (p = 0.0082) and anti-CCP antibodies (p = 0.008), but not smoking or shared-epitope alleles. Conclusion. Despite a significant prevalence of anti-CCP in FDR, anti-PAD4 antibodies were almost exclusively found in established RA. The prevalence of anti-PAD4 antibodies in RA is similar to the prevalence described in other populations and these autoantibodies are associated with disease duration and anti-CCP in RA.