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. Total mRNA profils of KIR+ and KIR- NK cells after h-HSCT

研究目的：本研究旨在探究自然杀伤（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）活化与未发生活化的患者中，经荧光激活细胞分选（Fluorescence Activated Cell Sorting, FACS）得到的杀伤细胞免疫球蛋白样受体（Killer Immunoglobulin-like Receptor, KIR）阳性（CD158b1b2j）与KIR阴性NK细胞的基因表达谱。
研究结果：流式细胞术检测数据证实，在h-HSCT患者发生HCMV活化后，KIR阳性NK细胞出现扩增富集，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阳性与KIR阴性NK细胞的基因表达谱，本研究发现存在细胞因子受体表达失衡、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，上述特征均符合适应性NK细胞的典型属性。通过对比发生HCMV活化与未活化患者体内KIR阳性NK细胞的分子特征谱，本研究观察到活化组中干扰素γ（Interferon Gamma, IFNG）基因以及信号受体活性、主要组织相容性复合体（Major Histocompatibility Complex, MHC）II类抗原呈递相关基因的表达上调，进一步支持了活化h-HSCT患者体内的KIR阳性NK细胞可在再次刺激下产生干扰素γ并介导特异性免疫应答的假说。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，活化h-HSCT患者体内的KIR阳性NK细胞可能存在效应功能受损的情况。本研究同时对h-HSCT术后的KIR阳性与KIR阴性NK细胞的全mRNA表达谱进行了分析。