Anti-carbamylated protein antibodies in unaffected first-degree relatives of rheumatoid arthritis patients: lack of correlation with anti-cyclic citrullinated protein antibodies and rheumatoid factor

Author information

CER8240
2015 Vol.33, N°6
PI 0824, PF 0830
Full Papers

Free to view
(click on article PDF icon to read the article)

PMID: 26411477 [PubMed]

Received: 24/12/2014
Accepted : 28/05/2015
In Press: 28/09/2015
Published: 15/12/2015

Abstract

OBJECTIVES:
To investigate the prevalence of anti-carbamylated protein antibodies (anti-CarP) in the healthy first-degree relatives (HFDRs) of patients with rheumatoid arthritis (RA).
METHODS:
We enrolled 141 HFDRs of 63 patients with RA diagnosed accordingly to the 2010 ACR/EULAR criteria. Fifty-six normal healthy subjects (NHS), sex- and age-matched, served as controls. Anti-CarP IgG, anti-cyclic citrullinated peptide antibody (anti-CCP) IgG and rheumatoid factors (RF) isotypes (IgG, IgA, IgM) were assessed by solid-phase ELISA.
RESULTS:
Anti-CarP were detectable in 13 HFDRs (9.2%), anti-CCP in 9 (6.3%), IgG-RF in 10 (7%), IgA-RF in 17 (12%), and IgM-RF in 13 (9.2%) HFDRs. Twenty-nine (46%) RA patients were positive for anti-CarP, 31 (49.2%) for anti-CCP, and 34 (53.9%) for RF. One NHS (1.7%) resulted positive for anti-CarP, none for anti-CCP and RF. Anti-CarP showed significantly higher serum levels in RA and HFDRs than in NHS (p<0.0001 and p=0.0012, respectively). A significant correlation between anti-CCP and RF were found among RA patients (p=0.0002), whereas no correlations were reported between autoantibodies tested in the HFDRs.
CONCLUSIONS:
Anti-CarP can be found in the sera of HFDRs of RA patients and their prevalence is significantly higher than in NHS. No correlation of anti-CarP with anti-CCP and RF antibodies in RA HFDRs was found.