Therapeutic gene editing of T cells to correct CTLA-4 insufficiency

Abstract

Heterozygous mutations inCTLA-4result in an inborn error of immunity with an autoimmune and frequently severe clinical phenotype. Autologous T cell gene therapy may offer a cure without the immunological complications of allogeneic hematopoietic stem cell transplantation. Here, we designed a homology-directed repair (HDR) gene editing strategy that inserts theCTLA-4cDNA into the first intron of theCTLA-4genomic locus in primary human T cells. This resulted in regulated expression of CTLA-4 in CD4+T cells, and functional studies demonstrated CD80 and CD86 transendocytosis. Gene editing of T cells isolated from three patients with CTLA-4 insufficiency also restored CTLA-4 protein expression and rescued transendocytosis of CD80 and CD86 in vitro. Last, gene-corrected T cells fromCTLA-4−/−mice engrafted and prevented lymphoproliferation in an in vivo murine model of CTLA-4 insufficiency. These results demonstrate the feasibility of a therapeutic approach using T cell gene therapy for CTLA-4 insufficiency.