Total RNA sequencing of KIR+ and KIR- NK cells from patients experiencing or not a Cytomegalovirus reactivation after haploidentical hematopoietic stem cell transplantation

AIM: To investigate the adaptive properties of NK cells, by comparing the expression profiles of FACS-sorted KIR+ (CD158b1b2j) and KIR- NK cells from patients experiencing or not a Cytomegalovirus (HCMV) reactivation after haploidentical hematopoietic stem cell transplantation (h-HSCT).RESULTS: Our flow cytometry data demonstrate that KIR+ NK cells are expanded in h-HSCT patients upon HCMV reactivation, thus suggesting that these cells could be important in controlling the viral infection and could be endowed with adaptive features.By comparing the expression profiles of KIR+ and KIR- NK cells from reacivated patients, we demonstrated a cytokine receptor unbalance, a prevalence of pathways associated to mitochondrial respiration and consequent ATP synthesis, a downregulation of genes involved in epigenetic reprogramming, all properties attributable adaptive NK cells.By comparing the molecular fingerprint of KIR+ NK cells between patients experiencing a HCMV reactivation and not reactivated patients, we observed in reactivated group an upregulation of INFG expression and in genes involved in Signaling receptor activity and MHC class II antigen presentation , thus strengthens the hypothesis that our KIR+ NK cells in reactevated h-HSCT patients are able to produce IFN-γ driving specific responses upon re-stimulation. However, the enrichment in PD-1 signaling, let us speculate that KIR+ NK cells from reactivated h-HSCT patients have impaired effector-functions.

研究目的：本研究旨在探讨自然杀伤（Natural Killer, NK）细胞的适应性特性，通过对比单倍体相合造血干细胞移植（haploidentical hematopoietic stem cell transplantation, h-HSCT）后发生巨细胞病毒（Cytomegalovirus, HCMV）活化与未发生活化患者的经荧光激活细胞分选（Fluorescence-activated cell sorting, FACS）纯化的杀伤细胞免疫球蛋白样受体（Killer cell immunoglobulin-like receptor, KIR）阳性（KIR+，CD158b1b2j）与KIR- NK细胞的表达谱。
研究结果：本研究的流式细胞术数据显示，巨细胞病毒活化后，单倍体相合造血干细胞移植患者体内的KIR+ NK细胞发生扩增，提示此类细胞在控制病毒感染中发挥关键作用，并可能具备适应性免疫特性。通过对比活化患者体内KIR+与KIR- NK细胞的表达谱，本研究证实存在细胞因子受体失衡、线粒体呼吸及后续ATP合成相关通路占优、表观遗传重编程相关基因表达下调等特征，上述特性均符合适应性NK细胞的典型表现。通过对比巨细胞病毒活化与未活化患者体内KIR+ NK细胞的分子特征谱，本研究发现活化组中IFNG基因及参与信号受体活性、MHC II类抗原呈递的基因表达上调，进一步支持了以下假说：巨细胞病毒活化的单倍体相合造血干细胞移植患者体内的KIR+ NK细胞可产生干扰素-γ（Interferon-gamma, IFN-γ），在再次刺激后触发特异性免疫应答。然而，程序性死亡受体1（Programmed cell death protein 1, PD-1）信号通路的富集提示，此类患者体内的KIR+ NK细胞可能存在效应功能受损的情况。