ISSN 1866-8836
Клеточная терапия и трансплантация

PO-11. Comparative analysis of ex vivo and in vivo TCRαβ+ depletion in hematopoietic stem cell transplantation

Anna A. Vlasova1, Larisa V. Vakhonina1,2, Natalya G. Maisheva1,2, Dmitry E. Klevakin1, Andrey A. Igumenshchev1,2, Tatyana Yu. Verzhbitskaya1,2, Alexander I. Ponomarev1,2,3, Jean V. Permikin1,3, Grigory A. Tsaur1,2,3, Larisa G. Fechina1,2

1 Regional Children’s Clinical Hospital, Yekaterinburg, Russia
2 Institute of Medical Cellular Technologies, Yekaterinburg, Russia
3 Ural State Medical University, Yekaterinburg, Russia


Contact: Dr. Anna A. Vlasova, phone: +7(912) 654-97-62, e-mail: avlasova2507@gmail.com

doi 10.18620/ctt-1866-8836-2023-12-3-1-176

Summary

Hematopoietic stem cell transplantation is a widely used therapeutic option in the treatment strategy for various malignant and non-malignant hematological pathologies. Alloreactive donor and recipient T cells represent one of the most significant obstacles to the successful outcome of allogeneic HSCT. Recipients’ T-lymphocytes affect the engraftment and graft functioning and may provoke its non-engraftment and/or rejection. Donor T-lymphocytes can induce severe acute and chronic graft-versus-host disease (GvHD). The purpose of this work is a retrospective analysis of the results of HSCTs performed at the Center for Pediatric Oncology and Hematology (Yekaterinburg) in 2010-2023 years.

Results

Data from 118 cases of HSCT performed for 107 patients with malignant neoplasms were analyzed. All patients were divided into 2 groups: (1) ex vivo TCRαβ+/CD19+ depletion using Clinimac Plus (Miltenyi Biotec, Germany) (n=75), (2) in vivo depletion using post-transplant cyclophosphamide 50 mg/kg (PTCY) (n=43). The best survival was recorded in group (1), showing significant differences with group (2): the median survival time was reached at +12 days in group (1) and +18 days in group (2). The probability of CMV reactivation in the posttransplant period did not differ significantly in groups (1) and (2) and amounted to 0.467 and 0.466, respectively (p>0.05). At the same time, the probability of reactivation of HSV type 6 was 0.360 in group (1) versus 0.240 in group (2), however, no statistically significant differences were found (p=0.13). The probability of acute GvHD by day +100 did not differ significantly in patients of the two groups (1) and (2) and amounted to 0.294 and 0.419, respectively (p=0.77). The probability of developing severe acute GvHD (stages 3-4) also did not differ significantly between the groups: 0.067 and 0.093, respectively. The probability of developing chronic GvHD was 0.12 in group (1) and 0.26 in group (2), which had no statistical difference (p=0.11). The probability of relapse did not differ statistically in the two groups and amounted to 0.45 (1) and 0.56 (2), respectively (p=0.35). Event-free survival was 73.3% in group (1) and 67.4% in group (2). Overall survival was 0.61 in group (1) and 0.75 in group (2) (p=0.30).

Conclusion

Our results show that despite differences in engraftment rates, there were no significant differences in relapse rates and OS. Our data, as well as literature data, demonstrate a decreased risk of reactivation of viral infections in the post-transplant period in group (2), presumably due to the preservation of antiviral immunity and rapid immune reconstitution. This approach is preferred for a group of patients at have a high risk of viral infections. The choice of transplant tactics should be multifactorial and patient-oriented.

Keywords

Hematopoietic stem cell transplantation, TCRαβ+/CD19+ depletion, posttransplant cyclophosphamide.



Supplement 12-3
09/30/2023

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doi 10.18620/ctt-1866-8836-2023-12-3-1-176

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