title: In vivo tracking of T cells in humans unveils decade-long survival and activity of genetically modified T memory stem cells.
abstract: A definitive understanding of survival and differentiation potential in humans of T cell subpopulations is of paramount importance for the development of effective T cell therapies. In particular, uncovering the dynamics in vivo in humans of the recently described T memory stem cells (TSCM) would be crucial for therapeutic approaches that aim at taking advantage of a stable cellular vehicle with precursor potential. We exploited data derived from two gene therapy clinical trials for an inherited immunodeficiency, using either retrovirally engineered hematopoietic stem cells or mature lymphocytes to trace individual T cell clones directly in vivo in humans. We compared healthy donors and bone marrow-transplanted patients, studied long-term in vivo T cell composition under different clinical conditions, and specifically examined TSCM contribution according to age, conditioning regimen, disease background, cell source, long-term reconstitution, and ex vivo gene correction processing. High-throughput sequencing of retroviral vector integration sites (ISs) allowed tracing the fate of more than 1700 individual T cell clones in gene therapy patients after infusion of gene-corrected hematopoietic stem cells or mature lymphocytes. We shed light on long-term in vivo clonal relationships among different T cell subtypes, and we unveiled that TSCM are able to persist and to preserve their precursor potential in humans for up to 12 years after infusion of gene-corrected lymphocytes. Overall, this work provides high-resolution tracking of T cell fate and activity and validates, in humans, the safe and functional decade-long survival of engineered TSCM, paving the way for their future application in clinical settings.
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy. luca.biasco@hsr.it a.aiuti@hsr.it.
authors: Luca
authors: L
authors: Biasco
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy. Vita-Salute San Raffaele University, Milan 20132, Italy.
authors: Serena
authors: S
authors: Scala
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Luca
authors: L
authors: Basso Ricci
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Francesca
authors: F
authors: Dionisio
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Cristina
authors: C
authors: Baricordi
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Andrea
authors: A
authors: Calabria
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Stefania
authors: S
authors: Giannelli
authors: IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Nicoletta
authors: N
authors: Cieri
authors: Pediatric Immunohematology and Stem Cell Programme, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Federica
authors: F
authors: Barzaghi
authors: Pediatric Immunohematology and Stem Cell Programme, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Roberta
authors: R
authors: Pajno
authors: King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia.
authors: Hamoud
authors: H
authors: Al-Mousa
authors: Department of Pediatrics, Ospedale Pediatrico Bambino Gesù and University of Rome "Tor Vergata," Rome 00165, Italy.
authors: Alessia
authors: A
authors: Scarselli
authors: Department of Pediatrics, Ospedale Pediatrico Bambino Gesù and University of Rome "Tor Vergata," Rome 00165, Italy.
authors: Caterina
authors: C
authors: Cancrini
authors: Vita-Salute San Raffaele University, Milan 20132, Italy.
authors: Claudio
authors: C
authors: Bordignon
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy. Vita-Salute San Raffaele University, Milan 20132, Italy.
authors: Maria Grazia
authors: MG
authors: Roncarolo
authors: San Raffaele Telethon Institute for Gene Therapy (TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Eugenio
authors: E
authors: Montini
authors: IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.
authors: Chiara
authors: C
authors: Bonini
authors: Department of Pediatrics, Ospedale Pediatrico Bambino Gesù and University of Rome "Tor Vergata," Rome 00165, Italy. TIGET, Pediatric Immunohematology and Stem Cell Programme, San Raffaele Scientific Institute, Milan 20132, Italy. luca.biasco@hsr.it a.aiuti@hsr.it.
authors: Alessandro
authors: A
authors: Aiuti
mesh_terms: D000328:Adult; D002470:Cell Survival; D058948:Cell Tracking; D002648:Child; D002999:Clone Cells; D005818:Genetic Engineering; D015316:Genetic Therapy; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007156:Immunologic Memory; D007376:Interleukin-2 / Q000494:pharmacology; D008137:Longitudinal Studies; D016131:Lymphocyte Subsets / Q000378:metabolism; D010641:Phenotype; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014019:Tissue Donors
chemical_list: D007376:Interleukin-2; D013755:Tetradecanoylphorbol Acetate