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. 2016 Sep 1;11(9):e0162101.
doi: 10.1371/journal.pone.0162101. eCollection 2016.

Regulatory CD4+ T-Cell Subsets and Anti-Citrullinated Protein Antibody Repertoire: Potential Biomarkers for Arthritis Development in Seropositive Arthralgia Patients?

Affiliations

Regulatory CD4+ T-Cell Subsets and Anti-Citrullinated Protein Antibody Repertoire: Potential Biomarkers for Arthritis Development in Seropositive Arthralgia Patients?

Koen M J Janssen et al. PLoS One. .

Abstract

Objective: Seropositive arthralgia patients (SAP) are at high risk of developing rheumatoid arthritis (RA). This prospective study aimed to determine whether altered peripheral regulatory T-cells (Tregs) and defined subsets, besides a broadened anti-citrullinated protein antibody (ACPA) response, may qualify as biomarkers for RA development in SAP.

Methods: Thirty-four consecutive SAP were prospectively assessed every 6 months for minimally 2 years. At inclusion, peripheral Treg (CD4+CD25+FoxP3+) numbers and subsets, defined as CD45RA+FoxP3low naive Tregs (Fr I), CD45RA-FoxP3high activated Tregs (Fr II) and CD45RA-FoxP3low non-Tregs (Fr III), were compared to age- and sex-matched healthy controls (HC, n = 16) and treatment-naive RA patients (n = 12). SAP that developed RA were compared to non-switchers and analyzed for Treg numbers and Treg subsets at inclusion. Also, Treg numbers and subsets were compared in switched SAP before and at diagnosis. To assess the ACPA repertoire, IgG and IgA reactivity was measured against citrullinated peptides from fibrinogen, α-enolase and vimentin.

Results: Treg numbers were similar between HC, SAP and RA patients. Although the bonafide Treg subsets Fr I and Fr II were comparable between groups, Fr III was increased in SAP compared to HC (p = 0.01). Fourteen (41%) SAP developed RA during follow-up. Their Treg numbers and subsets were comparable to non-switched SAP. At RA diagnosis, Treg numbers in switched SAP were similar to 6 months before. Switched SAP displayed a more diverse IgG ACPA repertoire compared to non-switched SAP (p = 0.046) and showed more IgA reactivity than non-switched SAP reaching significance for Fib1 only (p = 0.047).

Conclusion: Numbers of Total Treg and bonafide Treg subsets are not indicative for RA development in SAP, opposed to the ACPA repertoire.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Analysis of Treg subpopulations in healthy controls (HC), seropositive arthralgia patients (SAP) at inclusion and treatment-naive rheumatoid arthritis patients (RA).
(A) Three representative FACS analyses of CD25+FoxP3+ cells gated on CD4+ T-cells in HC, SAP and RA. (B) Percentages and absolute numbers of CD4+CD25+FOXP3+ cells negative for CD127 among CD4+ T-cells in HC, SAP and RA. (C) Three representative FACS analyses of Treg subpopulations gated on CD4+ T-cells in HC, SAP and RA. (D) Percentages and absolute numbers of naive Tregs (Fr I), activated Tregs (Fr II) and non-suppressive Tregs (Fr III) in HC, SAP and RA. Mann Whitney U test was used to compare groups. Horizontal bars indicate the median.
Fig 2
Fig 2. Treg subsets in SAP who switched or did not switch to RA.
(A) Percentages and absolute numbers of CD4+CD25+FoxP3+ T-cells and (B) Treg subpopulations in non-switched vs switched SAP at inclusion. (C) Percentages and absolute numbers of CD4+CD25+FoxP3+ T-cells and (D) Treg subpopulations in switched SAP at the time of RA diagnosis and 6 months before. Mann Whitney U test was used to compare groups and paired t-test was used to compare paired samples. No significant differences were observed. Horizontal bars indicate the median.
Fig 3
Fig 3. Reactivity against citrullinated peptides from fibrinogen (Fib1, Fib2), α-enolase (Eno1) and vimentin (Vim1) in SAP sera at inclusion.
(A) IgG seropositivity (B) IgA seropositivity. Reactivity is shown as percentage within the group of patients that switched or did not switch to RA. Fisher’s exact test was used to compare groups.

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References

    1. Klareskog L, Ronnelid J, Lundberg K, Padyukov L, Alfredsson L. Immunity to citrullinated proteins in rheumatoid arthritis. Annu Rev Immunol. 2008;26: 651–675. 10.1146/annurev.immunol.26.021607.090244 - DOI - PubMed
    1. Willemze A, Trouw LA, Toes RE, Huizinga TW. The influence of ACPA status and characteristics on the course of RA. Nat Rev Rheumatol. 2012;8: 144–152. 10.1038/nrrheum.2011.204 - DOI - PubMed
    1. Nielen MM, van Schaardenburg D, Reesink HW, van de Stadt RJ, van der Horst-Bruinsma IE, de Koning MH, et al. Specific autoantibodies precede the symptoms of rheumatoid arthritis: a study of serial measurements in blood donors. Arthritis Rheum. 2004;50: 380–386. - PubMed
    1. Shi J, van de Stadt LA, Levarht EW, Huizinga TW, Hamann D, van Schaardenburg D, et al. Anti-carbamylated protein (anti-CarP) antibodies precede the onset of rheumatoid arthritis. Ann Rheum Dis. 2014;73: 780–783. 10.1136/annrheumdis-2013-204154 - DOI - PubMed
    1. Kokkonen H, Soderstrom I, Rocklov J, Hallmans G, Lejon K, Rantapaa Dahlqvist S. Up-regulation of cytokines and chemokines predates the onset of rheumatoid arthritis. Arthritis Rheum. 2010;62: 383–391. 10.1002/art.27186 - DOI - PubMed