Abstract:

Objective By dynamically monitoring the lymphocyte subsets of blood disease patients at 30，60 and 90 d after allogeneic hematopoietic stem cell transplantation（allo-HSCT），to investigate the correlation between lymphocyte subset changes and the occurrence of acute graft-versus-host disease（aGVHD） after allo-HSCT and the clinical significance of lymphocyte subset monitoring for aGVHD. Methods Totally，33 patients who underwent allo-HSCT at the First Medical Center of Chinese People's Liberation Army General Hospital from January 2019 to December 2021 were enrolled. According to whether the patients developed aGVHD，the patients were classified into aGVHD group（19 cases） and non-aGVHD group（14 cases）. Flow cytometry was used to determine lymphocyte subsets（CD3⁺，CD4⁺，CD8⁺，CD19⁺，CD16⁺CD56⁺） and regulatory T cells（CD4⁺CD25⁺FOXP3⁺） at 30，60 and 90 d after transplantation. The changes of lymphocyte subsets were characterized，and the difference in lymphocyte subsets between aGVHD and non-aGVHD groups was compared. Results The relative count of natural killer（NK） cells reached a high level at 30 d after transplantation and gradually decreased to normal levels at 60 d，while B cells remained at a low level for a long time. T cells were at a low level on the 30th day and returned to normal levels after 60 d. The levels of CD8⁺ were higher than those of CD4⁺ at each monitoring time point. For the relative counts of lymphocyte subsets，the levels of NK cells，total T，CD8⁺，CD8⁺CD28⁺ and CD8⁺CD28^- had statistical significance between each time point（P<0.05）. For the absolute counts，there was statistical significance among the 3 time points of CD3⁺，CD4⁺ and CD8⁺ （P<0.05），but there was no statistical significance between NK cells and B cell subsets. There was statistical significance in CD4⁺ on the 60th day between aGVHD and non-aGVHD patients（P<0.05）. There was statistical significance in regulatory T cells between the 2 groups on the 30th day（P<0.05），while the differences in other lymphoid subpopulations had no statistical significance（P>0.05）. Conclusions For patients undergoing hematopoietic stem cell transplantation（HSCT），regular determination of lymphocyte subsets is of importance for monitoring the process of immune reestablishment. Dynamic monitoring of regulatory T cells is helpful for timely diagnosis and prevention of aGVHD，thus further improving the survival rate of patients.

Key words: Lymphocyte subset, Regulatory T cell, Hematopoietic stem cell transplantation, Graft-versus-host disease