Human T cell generation is restored in CD3δ severe combined immunodeficiency through adenine base editing

Cell. 2023 Mar 30;186(7):1398-1416.e23. doi: 10.1016/j.cell.2023.02.027. Epub 2023 Mar 20.


CD3δ SCID is a devastating inborn error of immunity caused by mutations in CD3D, encoding the invariant CD3δ chain of the CD3/TCR complex necessary for normal thymopoiesis. We demonstrate an adenine base editing (ABE) strategy to restore CD3δ in autologous hematopoietic stem and progenitor cells (HSPCs). Delivery of mRNA encoding a laboratory-evolved ABE and guide RNA into a CD3δ SCID patient's HSPCs resulted in a 71.2% ± 7.85% (n = 3) correction of the pathogenic mutation. Edited HSPCs differentiated in artificial thymic organoids produced mature T cells exhibiting diverse TCR repertoires and TCR-dependent functions. Edited human HSPCs transplanted into immunodeficient mice showed 88% reversion of the CD3D defect in human CD34+ cells isolated from mouse bone marrow after 16 weeks, indicating correction of long-term repopulating HSCs. These findings demonstrate the preclinical efficacy of ABE in HSPCs for the treatment of CD3δ SCID, providing a foundation for the development of a one-time treatment for CD3δ SCID patients.

Keywords: CD3D severe combined immune deficiency; CITE-seq; artificial thymic organoid; base editing; hematopoietic stem and progenitor cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD3 Complex
  • Gene Editing
  • Humans
  • Mice
  • Mice, SCID
  • Receptors, Antigen, T-Cell / genetics
  • Severe Combined Immunodeficiency* / genetics
  • Severe Combined Immunodeficiency* / therapy
  • T-Lymphocytes*


  • CD3 Complex
  • Receptors, Antigen, T-Cell