Post-transplantation monitoring and quantitation of microparticles in allogeneic hematopoietic cell transplantation

Abstract

Background: Allogeneic hematopoietic stem cell transplantation (allo-HCT) represents a curative treatment for various blood-related disorders, including hematological malignancies and genetic disorders. The success of this procedure hinges on the efficacy of the conditioning regimen and the graft's ability to engraft and function properly. Microparticles (MPs), small vesicles produced from stimulated, apoptotic, or activated cells, are involved in both physiological and pathological processes. However, the impact of MPs on allo-HCT remains poorly understood.

Objectives: This study aimed to investigate the presence of MPs from different cell types in grafts and patient plasma after allo-HCT, as well as their association with various parameters. We measured MPs from CD34+, CD56+, CD3+, CD19+, and CD33+ cells in grafts and patient plasma from day 0 to day 60 after transplantation.

Methods: 224 blood samples were collected from 19 consecutive allo -HCT recipients at 0, +4, +14,+30 and + 60 day as well as from their grafts. MPs isolated from the plasma and quantified by flow cytometry analysis.

Results: MP levels varied over time. Notably, CD34+ MP levels were linked to both early and late engraftment of neutrophils and platelets. Furthermore, grafts with high CD34+ and CD56+ MP levels in patient plasma on days 0 and + 4 were associated with late engraftment, whereas high CD33+ MP levels in both graft and patient plasma on day +4 were associated with early engraftment. Conditioning regimen affected CD19+ MP levels at day +14, and the number of CD34+, CD56+, and CD19+ MPs 30 days after transplantation was correlated with acute graft-versus-host disease.

Conclusion: These findings suggest that MPs derived from hematopoietic cells may play a significant role in the clinical course of patients following allo-HCT.

Keywords: Allogeneic transplantation; CD34+,CD56+,CD3+,CD19+ and CD33+ microparticles; CD34+,CD56+,CD3+,CD19+ and CD33 + cells; Microparticles; Neutrophil and platelet engraftment.