Ab1277 prevalence of the Different Anti-Carbamylated Protein Antibodies Isoforms in First-Degree Relatives of Patients With Rheumatoid Arthritis in a Latin Population

Abstract

BackgroundRheumatoid arthritis (RA) affects approximately 1.5% of the population worldwide and 0.5-3.3% of the Mexican population1. Anti-carbamylated proteins (anti-CarP) antibodies are identified in RA patients with a prevalence up to 44%2, early arthritis, first-degree relatives (FDR) of patients with RA with a prevalence of 18%, and healthy controls with a prevalence of 4.7%. There is no evidence regarding the prevalence of the three different isoforms of anti-CarP antibodies worldwide.ObjectivesEstablish the prevalence of the different isoforms of anti-CarP antibodies (IgA, IgM, IgG) in FDRs of patients with RA.MethodsIt is an observational descriptive cohort. Subjects underwent a complete physical examination, made by a certificated rheumatologist, which included clinical and serological measurements. The serological measurements included anti-citrullinated peptides antibodies (ACPA), RF, and anti-CarP detected by ELISA using carbamylated fetal calf serum, according to Shin J et al with some modifications. The cut-offs for the anti-CarP IgA isoform was >125 U/mL, for the IgG isoform was >90 U/mL, and for the IgM isoform was >300 U/mL. The FDRs were classified as: suspicious arthralgia for progression according to Van Steenvergen criteria; undifferentiated arthritis (UA) and RA according to ACR/EULAR 2010; and soft tissue rheumatic diseases.ResultsA total of 144 FDRs from 99 RA patients were enrolled. The demographic characteristics are shown in Table 1. The prevalence (Table 2) for anti-CarP was 2.8% for IgA, 4.2% for IgG, whereas IgM was not detected. The serologic association was for RF/ACPA 4.48%, RF/anti-CarP 2.7%, FR 64.5%, ACPA 1.3%, ACPA/anti-CarP 0.69%, anti-CarP 3.4%, and no RF/ACPA/anti-Carp was observed.The group of suspicious arthralgia for progression had to 2 subjects positive for IgG anti-CarP, the group of UA had 1 subject positive for IgA anti-CarP, albeit no anti-CarP for the RA group was present. Soft tissue rheumatic diseases group had 5 subjects positive for IgG anti-CarP, while the asymptomatic group had 2 subjects positive for IgA anti-CarP. Table 1 Population, n (%)144 (100%)Age (years), median (IQR)45.25 (18-76)Weight (kg), median (IQR)70 (42-117)Height (meters), median (IQR)1.61 (1.44-1.88)BMI, median (IQR)26.19 (16.7-47.3)Female, n (%)119 (82%)HAQ, median (IQR)0.29 (0-2.15)IQR: interquartile range, Kg: kilograms; BMI: body mass index, HAQ: Health Assesment QuestionareAbstract AB1277 Table 2POSITIVE, n (%)MIN/MAXMEDIANCRP, mg/dL19 (13%)0.0-2.270.36ESR, mm/H; mean (SD)37 (25.3%)1-7213.0 (11.95)Anti-CarP, U/mLIgA4 (2.8%)0.0-8182.0IgM0 (0.0%)0.0-565.45IgG6 (4.2%)0.0-1878.0Rheumatoid Factor, U/mLIgA31 (21.5%)1-2196.96IgM64 (44.4%)1-20515IgG14 (9.7%)1-1603.04ACPA-IgG, U/mL10 (7%)1-2001.21CRP: C Reactive Protein; ESR: erythrocyte Sedimentation Rato; anti-CarP: Anti-Carbamylated Protein; SD: Standard Deviation; ACPA: anti-Citrullinated Peptides Antibodies.ConclusionEven though we used the 3 isoforms of anti-CarP antibodies, the prevalence of these antibodies in our cohort showed less positi...

Comparison of oxidative stress, lipid peroxidation and inflammatory markers between rheumatoid arthritis and ankylosing spondylitis patients

“…After approval from the AMC ethics review board, the sample size was estimated using the World Health Organisation (WHO) calculator with prevalence 1.5%, confidence interval (CI) 95% and error 5%. 8,9 The sample was raised using non-probability purposive sampling technique. Those included were individuals of either gender aged between 25-70 years.…”