Multilineage hematopoietic reconstitution without clonal selection in ADA-SCID patients treated with stem cell gene therapy.
Gene transfer into HSCs is an effective treatment for SCID, although potentially limited by the risk of insertional mutagenesis. We performed a genome-wide analysis of retroviral vector integrations in genetically corrected HSCs and their multilineage progeny before and up to 47 months after transplantation into 5 patients with adenosine deaminase-deficient SCID. Gene-dense regions, promoters, and transcriptionally active genes were preferred retroviral integrations sites (RISs) both in preinfusion transduced CD34(+) cells and in vivo after gene therapy. The occurrence of insertion sites proximal to protooncogenes or genes controlling cell growth and self renewal, including LMO2, was not associated with clonal selection or expansion in vivo. Clonal analysis of long-term repopulating cell progeny in vivo revealed highly polyclonal T cell populations and shared RISs among multiple lineages, demonstrating the engraftment of multipotent HSCs. These data have important implications for the biology of retroviral vectors, the dynamics of genetically modified HSCs, and the safety of gene therapy.
Aiuti
Alessandro
A
San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Milan, Italy. a.aiuti@hsr.it
Cassani
Barbara
B
Andolfi
Grazia
G
Mirolo
Massimiliano
M
Biasco
Luca
L
Recchia
Alessandra
A
Urbinati
Fabrizia
F
Valacca
Cristina
C
Scaramuzza
Samantha
S
Aker
Memet
M
Slavin
Shimon
S
Cazzola
Matteo
M
Sartori
Daniela
D
Ambrosi
Alessandro
A
Di Serio
Clelia
C
Roncarolo
Maria Grazia
MG
Mavilio
Fulvio
F
Bordignon
Claudio
C
D048868:Adaptor Proteins, Signal Transducing; D000243:Adenosine Deaminase / Q000235:genetics; D018952:Antigens, CD34; D002675:Child, Preschool; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D015316:Genetic Therapy; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D007223:Infant; D060588:LIM Domain Proteins; D008297:Male; D008667:Metalloproteins / Q000235:genetics; D039902:Multipotent Stem Cells / Q000378:metabolism; D016254:Mutagenesis, Insertional; D011518:Proto-Oncogene Proteins; D012190:Retroviridae; D012307:Risk Factors; D016511:Severe Combined Immunodeficiency / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D013601:T-Lymphocytes / Q000378:metabolism; D014182:Transplantation, Autologous; D016662:Virus Integration / Q000235:genetics*
D048868:Adaptor Proteins, Signal Transducing; D018952:Antigens, CD34; D004268:DNA-Binding Proteins; D060588:LIM Domain Proteins; C085117:LMO2 protein, human; D008667:Metalloproteins; D011518:Proto-Oncogene Proteins; D000243:Adenosine Deaminase