Frontiers in Immunology (Nov 2017)

Regulatory T Cells Suppress Inflammation and Blistering in Pemphigoid Diseases

  • Katja Bieber,
  • Shijie Sun,
  • Mareike Witte,
  • Anika Kasprick,
  • Foteini Beltsiou,
  • Martina Behnen,
  • Tamás Laskay,
  • Franziska S. Schulze,
  • Elena Pipi,
  • Niklas Reichhelm,
  • René Pagel,
  • Detlef Zillikens,
  • Enno Schmidt,
  • Enno Schmidt,
  • Tim Sparwasser,
  • Kathrin Kalies,
  • Ralf J. Ludwig,
  • Ralf J. Ludwig

DOI
https://doi.org/10.3389/fimmu.2017.01628
Journal volume & issue
Vol. 8

Abstract

Read online

Regulatory T cells (Tregs) are well known for their modulatory functions in adaptive immunity. Through regulation of T cell functions, Tregs have also been demonstrated to indirectly curb myeloid cell-driven inflammation. However, direct effects of Tregs on myeloid cell functions are insufficiently characterized, especially in the context of myeloid cell-mediated diseases, such as pemphigoid diseases (PDs). PDs are caused by autoantibodies targeting structural proteins of the skin. Autoantibody binding triggers myeloid cell activation through specific activation of Fc gamma receptors, leading to skin inflammation and subepidermal blistering. Here, we used mouse models to address the potential contribution of Tregs to PD pathogenesis in vivo. Depletion of Tregs induced excessive inflammation and blistering both clinically and histologically in two different PD mouse models. Of note, in the skin of Treg-depleted mice with PD, we detected increased expression of different cytokines, including Th2-specific IL-4, IL-10, and IL-13 as well as pro-inflammatory Th1 cytokine IFN-γ and the T cell chemoattractant CXCL-9. We next aimed to determine whether Tregs alter the migratory behavior of myeloid cells, dampen immune complex (IC)-induced myeloid cell activation, or both. In vitro experiments demonstrated that co-incubation of IC-activated myeloid cells with Tregs had no impact on the release of reactive oxygen species (ROS) but downregulated β2 integrin expression. Hence, Tregs mitigate PD by altering the migratory capabilities of myeloid cells rather than their release of ROS. Modulating cytokine expression by administering an excess of IL-10 or blocking IFN-γ may be used in clinical translation of these findings.

Keywords