Artikel
Proportions of regulatory T cells (Treg) and suppressive Treg function in patients with psoriasis arthritis (PsA) or spondyloarthritis (SpA) after switching to anti-IL-17 treatment
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Veröffentlicht: | 9. September 2020 |
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Introduction: A dysbalance between IL-17-producing helper T (Th17) cells and regulatory T cells (Treg) has been proposed for T cell-mediated autoimmune arthritis. Blockers of IL-17 are successfully used for psoriatic arthritis (PsA) and spondyloarthritis (SpA). However, so far reconstitution of Treg functions has not been investigated in detail in patients with autoimmune arthritis eligible for switching to anti-IL-17 treatment. The project aims to investigate the reconstitution and maintenance of regulatory T cell (Treg) function after inhibition of IL-17 in a longitudinal manner.
Methods: Therefore, Treg derived from PsA and SpA patients and from healthy controls were phenotypically characterized by flow cytometry at two distinct time points after switching to Th17 inhibition. In vitro Treg function was determined by analysis of suppressive activity on proliferation of autologous effector T cells using suppression assays.
Results: Preliminary results suggested PsA and SpA to be Th17-mediated autoimmune disorders, as proportions of T cells with Th17 phenotype (CD4+CCR6+IL17+) were increased in PsA (mean 1.2% of CD4+) and SpA (1.1%) compared to controls (0.4%). Proportions of CD25brightFoxP3+ Treg were lower in PsA (mean 0.4% of CD4+) compared to controls (1.2%) and similar in SpA (1.0%). Regarding functionality of Treg, less suppression of autologous effector T cells co-cultured with CD25+ Treg was found in PsA compared to controls (22.2% vs. 28.3% reduction of proliferative activity) before switching to anti-IL-17 treatment, whereas CD25- helper T cells did not contribute to the suppression of effectors in PsA and only minimally in controls. About three months after switching to anti-IL-17 treatment, proportions of Th17 decreased (mean 0.3% of CD4+) in all patients. Proportions of Treg increased to 1.8% in PsA similar to proportions found in controls.
Conclusion: The preliminary results indicate a reduction of Th17 cells during anti-IL-17 treatment and an increase of peripheral Treg particularly in PsA patients. Longitudinal results regarding the reconstitution and maintenance of Treg function in those patients have to be awaited.
Disclosures: Nothing to declare