PT  - JOURNAL ARTICLE
AU  - J. Joseph Melenhorst
AU  - Gregory M. Chen
AU  - Meng Wang
AU  - David L. Porter
AU  - Peng Gao
AU  - Shovik Bandyopadhyay
AU  - Iulian Pruteanu-Malinici
AU  - Christopher L. Nobles
AU  - Sayantan Maji
AU  - Noelle V. Frey
AU  - Saar I. Gill
AU  - Lifeng Tian
AU  - Irina Kulikovskaya
AU  - Minnal Gupta
AU  - Megan M. Davis
AU  - Joseph A. Fraietta
AU  - Jennifer L. Brogdon
AU  - Regina M. Young
AU  - David E. Ambrose
AU  - Anne Chew
AU  - Bruce L. Levine
AU  - Donald L. Siegel
AU  - Cécile Alanio
AU  - E. John Wherry
AU  - Frederic D. Bushman
AU  - Simon F. Lacey
AU  - Kai Tan
AU  - Carl H. June
TI  - Decade-long remissions of leukemia sustained by the persistence of activated CD4<sup>+</sup> CAR T-cells
AID  - 10.1101/2021.05.07.443194
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.05.07.443194
4099  - http://biorxiv.org/content/early/2021/05/07/2021.05.07.443194.short
4100  - http://biorxiv.org/content/early/2021/05/07/2021.05.07.443194.full
AB  - The adoptive transfer of T lymphocytes reprogrammed to target tumor cells has demonstrated significant potential in various malignancies. However, little is known about the long-term potential and the clonal stability of the infused cells. Here, we studied the longest persisting CD19-redirected chimeric antigen receptor (CAR) T cells to date in two chronic lymphocytic leukemia (CLL) patients who achieved a complete remission in 2010. CAR T-cells were still detectable up to 10+ years post-infusion, with sustained remission in both patients. Surprisingly, a prominent, highly activated CD4+ population developed in both patients during the years post-infusion, dominating the CAR T-cell population at the late time points. This transition was reflected in the stabilization of the clonal make-up of CAR T-cells with a repertoire dominated by few clones. Single cell multi-omics profiling via Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-Seq) with TCR sequencing of CAR T-cells obtained 9.3 years post-infusion demonstrated that these long-persisting CD4+ CAR T-cells exhibited cytotoxic characteristics along with strong evidence of ongoing functional activation and proliferation. Our data provide novel insight into the CAR T-cell characteristics associated with long-term remission in leukemia.Competing Interest StatementJJM, DLP, JAF, SFL, CHJ hold patents related to CAR T-cell manufacturing and biomarker discovery. IPM and JN are employees of Novartis. The remaining authors declare that they have no competing interests.