[Problems and progress of autologous hematopoietic stem cell transplantation in multiple myeloma]

Fate of hematopoietic stem cells determined by Notch1 signaling (Review)

Regulation of the fate of hematopoietic stem cells (HSCs), including silencing, self-renewal or differentiation into blood line cells, is crucial to maintain the homeostasis of the human blood system and prevent leukemia. Notch1, a key receptor in the Notch signaling pathway, plays an important regulatory role in these properties of HSCs, particularly in the maintenance of the stemness of HSCs. In recent decades, the ubiquitination modification of Notch1 has been gradually revealed, and also demonstrated to affect the proliferation and differentiation of HSCs. Therefore, a detailed elucidation of Notch1 and its ubiquitination modification may help to improve understanding of the maintenance of HSC properties and the pathogenesis of leukemia. In addition, it may aid in identifying potential therapeutic targets for specific leukemias and provide potential prognostic indicators for HSC transplantation (HSCT). In the present review, the association between Notch1 and HSCs and the link between the ubiquitination modification of Notch1 and HSCs were described. In addition, the association between abnormal HSCs mediated by Notch1 or ubiquitinated Notch1and T-cell acute lymphoblastic leukemia (T-ALL) was also examined, which provides a promising direction for clinical application.

[Comparison of single infusion of anti-BCMA versus combined infusion of anti-CD19 chimeric antigen receptor T cells for immune reconstruction in relapsed/refractory multiple myeloma]

Objective: We observed and compared the differences in immune reconstruction between single-infusion anti-B-cell maturation antigen (BCMA) , chimeric antigen receptor T cells (CAR-T) , and combined infusion of anti-CD19 CAR-T cells in the treatment of recurrent/refractory multiple myeloma (RRMM) . Methods: Sixty-one patients with RRMM who underwent CAR-T cell therapy in our hospital from June 2017 to December 2020 were selected. Among them, 26 patients received anti-BCMA target, and 35 patients received anti-BCMA combined with anti-CD19 target. Using flow cytometry, we determined T cell subsets (CD3(+), CD4(+), CD8(+), CD4(+)/CD8(+)) , B cells (CD19(+)) , and NK cells (CD16(+) CD56(+)) at different time points before and after CAR-T treatment, and detected immunoglobulin IgG, IgA and IgM levels by immunoturbidimetry. We compared the reconstruction rules of lymphocyte subsets and immunoglobulins in the two groups. Results: CD8(+) T lymphocytes recovered most rapidly after the infusion of CAR-T cells, returning to pre-infusion levels at 3 months and 1 month after infusion, respectively[BCMA: 695 (357, 1264) /μl vs 424 (280, 646) /μl; BCMA+CD19: 546 (279, 1672) /μl vs 314 (214, 466) /μl]. NK cells returned to normal levels at 3 months after infusion in both groups[BCMA: 171 (120, 244) /μl, BCMA+CD19: 153 (101, 218) /μl (Normal reference range 150-1100/μl) ]; however, the NK cells were not maintained at stable levels in the BCMA CAR-T cells group. The recovery of CD4(+) T lymphocytes in both groups was slow and remained persistently low within 12 months after infusion, and no recovery was observed in most patients. The reversal of the ratio of CD4(+)/CD8(+) lasted for more than a year. The levels of CD19(+) B cells in both groups returned to baseline 3 months after infusion[BCMA: 62 (10, 72) /μl vs 57 (24, 78) /μl; BCMA+CD19: 40 (4, 94) /μl vs 29 (14, 46) /μl]. IgG returned to the pre-infusion level 12 months after infusion in the group with anti-BCMA cells alone, but not in the group with combined infusion of CD19 CAR T cells[7.82 (6.03, 9.64) g/L vs 6.92 (4.62, 12.76) g/L]. IgA returned to pre-infusion levels at 9 and 12 months after infusion, respectively[BCMA: 0.46 (0.07, 0.51) g/L vs 0.22 (0.12, 4.01) g/L; BCMA+CD19: 0.46 (0.22, 0.98) g/L vs 0.27 (0.10, 0.53) g/L]. IgM in both groups returned to pre-infusion levels 6 months after infusion[BCMA: 0.43 (0.06, 0.60) g/L vs 0.20 (0.13, 0.37) g/L; BCMA+CD19: 0.53 (0.10, 0.80) g/L vs 0.16 (0.11, 0.28) g/L]. There was no significant difference in the indexes of lymphocyte subpopulation reconstruction and immunoglobulin recovery between the two groups at each time point. Conclusion: This study showed that in patients with RRMM treated with CAR-T cells, the appropriate target antigen can be selected without considering the difference of immune reconstruction between anti-BCMA CAR-T and combined anti-CD19 CAR-T therapy.