CD4+ FoxP3+ T regulatory cell subsets in myasthenia gravis patients

•A lower production of Treg can be observed in thymoma tissue.•Immunsuppression and thymectomy lead to changes in the distribution of Treg subpopulations in MG patients.•MG patients are characterized by a lower frequency of highly immunsuppressive CD45RA+ FoxP3low Treg.

Although myasthenia gravis (MG) is a classic autoantibody-mediated disease, T cells are centrally involved in its pathogenesis. In recent years a number of studies have analyzed the role of CD4+ FoxP3+ regulatory T cells (Treg) in the disease with contradictory results. Here, the generation of Treg was significantly reduced in thymoma as compared to thymic hyperplasia and normal thymus tissue (p = 0.0002). In the peripheral blood, Treg subsets classified according to CD49d, HELIOS and CD45RA expression changed after thymectomy and in the long-term course of immunosuppression. Compared to healthy volunteers the frequency of CD45RA+ FoxP3low Treg was reduced in MG patients in general (p = 0.037) and in particular in patients without immunosuppression (p = 0.036). In our study, thymectomy and immunosuppressive treatment were associated with changes in Treg subpopulations. The reduced frequency of CD45RA+ FoxP3low Treg we observed in MG patients might play a role in MG pathogenesis.