Janssen, ErinMorbach, HennerUllas, SumanaBannock, Jason M.Massad, ChristopherMenard, LaurenceBarlan, Isil2024-02-232024-02-2320140091-67491097-6825https://doi.org/10.1016/j.jaci.2014.07.042https://hdl.handle.net/20.500.12452/12074Background: Dedicator of cytokinesis 8 (DOCK8) deficiency is typified by recurrent infections, increased serum IgE levels, eosinophilia, and a high incidence of allergic and autoimmune manifestations. Objective: We sought to determine the role of DOCK8 in the establishment and maintenance of human B-cell tolerance. Methods: Autoantibodies were measured in the plasma of DOCK8-deficient patients. The antibody-coding genes from new emigrant/transitional and mature naive B cells were cloned and assessed for their ability to bind self-antigens. RegulatoryT(Treg) cells in the blood were analyzed by means of flow cytometry, and their function was tested by examining their capacity to inhibit the proliferation of CD4(+)CD25(-) effector T cells. Results: DOCK8-deficient patients had increased levels of autoantibodies in their plasma. We determined that central B-cell tolerance did not require DOCK8, as evidenced by the normally low frequency of polyreactive new emigrant/transitional B cells in DOCK8-deficient patients. In contrast, autoreactive B cells were enriched in the mature naive B-cell compartment, revealing a defective peripheral B-cell tolerance checkpoint. In addition, we found that Treg cells were decreased and exhibited impaired suppressive activity in DOCK8-deficient patients. Conclusions: Our data support a critical role for DOCK8 in Treg cell homeostasis and function and the enforcement of peripheral B-cell tolerance.eninfo:eu-repo/semantics/openAccessDedicator Of Cytokinesis 8AutoimmunityB-Cell ToleranceRegulatory T CellsArticle134613651374252182842-s2.0-84908440532Q1WOS:000346075400019Q110.1016/j.jaci.2014.07.042