The Correlation Between S1PR5 Expression Change In NK Cells In Peripheral Blood Pre-and Post-allo-HSCT And Acute GVHD

Objective:To study sphingosine-1-phosphate receptor 5 (S1PR5) expression change in natual killer (NK) cells in peripheral blood (PB) pre-and post-allogeneic hematopoietic stem cell transplantation (allo-HSCT) and explore the relationship between S1PR5 level change and frequency of causing acute graft-versus-host disease (aGVHD).Methods:(1) Peripheral blood mononuclear cells (PBMC) were separated by density gradient centrifugation from 17 couples of donor before mobilization and recipient 1 month after allo-HSCT; (2) NK cells were collected and purified by miniMACS using negative selection strategy and purities of CD56+CD3- cells were detected by flow cytometry; (3) Total RNA in purified NK cells were extracted using QIAamp RNA Blood Mini Kits; (4) NK cell cDNA synthesis reactions were performed using Promega Reverse Transcription System; (5) S1PR5 mRNA expression levels of donors and recipients were detected by real-time PCR technology and the relationship between S1PR5 level change in NK cells and occurrence of aGVHD was observed.Results:(1) High-purified NK cells were obtained using miniMACS magnetic separation system from pre-mobilization healthy donors and recipients'peripheral blood. (2) 10 out of 17 patients presented decrease of S1PR5 mRNA level 1 month after transplant compared with corresponding donors while 7 recipients showed increase inversely. S1PR5 mRNA level variations in NK cells in PB pre-and post-allo-HSCT were obviously different among individuals and the difference was not statistically significant. (3) 7 out of 9 recipients who developed aGVHD showed 10% or more decrease of S1PR5 levels in NK cells in PB 1 month after transplantation than corresponding donors, compared with 1 out of 7 patients who did not presented aGVHD. Conclusions:S1PR5 expression change in NK cells in PB per- and post-allo-HSCT may influence aGVHD occurrence by altering NK cell distribution. This study contributed to further understanding of NK cell reconstitution after HSCT, discovering new mechanisms of causing aGVHD and offered novel strategies to aGVHD prevention and targeted therapy.