Gene expression profiling of effector and regulatory T-cells from peripheral blood of rheumatoid arthritis (RA) patients and healthy volunteers.

Objective: Conflicting evidence exists regarding the suppressive capacity of Tregs from the peripheral blood (PB) of patients with rheumatoid arthritis (RA). Our aim was to determine whether Tregs are intrinsically defective in RA using a wide range of read-out assays. Methods: CD3+CD4+CD25+CD127low Tregs from CD45RO+ and CD45RA+ compartments of PB from patients with RA and healthy controls (HC) were analysed for phenotype, cytokine expression profile (ex vivo and after in vitro stimulation), suppression of effector T-cell proliferation and cytokine production, suppression of monocyte-derived cytokine/chemokine production, and gene expression profiling. Results: No differences were observed between patients with RA and HC regarding Treg frequency, ex vivo phenotype (CD4, CD25, CD127, CD39, CD161) or pro-inflammatory cytokine profile (IL-17, IFN-gamma, TNF-alpha). FOXP3 expression was increased in Tregs from RA blood. The ability of Tregs to suppress T-cell proliferation or cytokine (IFN-gamma, TNF-alpha) production upon co-culture with autologous CD45RO+ effector T-cells and monocytes was not significantly different between patients with RA and HC. CD45RO+ Tregs from RA blood showed a slightly impaired ability to suppress production of some cytokines/chemokines by autologous LPS-activated monocytes (IL-1-beta, IL-1Ra, IL-7, CCL3, CCL4), but this was not true for all patients and other cytokines/chemokines (TNF-alpha, IL-6, IL-8, IL-12, IL-15, CCL5) were suppressed in the majority of patients similarly to HC. Finally, gene expression profiling of CD45RA+ or CD45RO+ Tregs from PB revealed no statistically significant differences between patients with RA and HC. Conclusions: Our findings suggest that Tregs isolated from PB of patients with RA are not intrinsically defective.

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Walter GJ, Fleskens V, Frederiksen KS, Rajasekhar M, Menon B, Gerwien JG, Evans HG, Taams LS