CD56bright NK Cells Research Articles

Identification of Immune-Linked Hub Genes and Diagnostic Model Construction in Schizophrenia.

Schizophrenia (SCZ) is a prevalent, severe, and persistent mental disorder with an unknown etiology. Growing evidence indicates that immunological dysfunction is vital in the development of SCZ. Our study aims to uncover potential immune-linked hub genes and immune infiltration characteristics of SCZ, as well as to develop a diagnostic model based on immune-linked central genes. GSE38484 and GSE54913 chip expression data for patients with SCZ and healthy controls were retrieved. Weighted gene co-expression network analysis (WGCNA) was performed to identify major module genes and critical immune-linked genes. Functional enrichment analysis was conducted to elucidate the involvement of key genes in the immunological response to SCZ, along with the examination of their protein interactions. Moreover, 202 peripheral blood samples were examined using the single-sample gene set enrichment analysis (ssGSEA) method to detect distinct immune cell types. Hub immune-linked genes in SCZ were identified using the minimal absolute contraction and selection operator analysis. Receptor profiles of central immune-linked genes were analyzed to distinguish the two groups. Finally, the association between immune-linked hub genes and various types of immune cells was assessed. Our findings revealed ten immune cell types and nine key genes involved in SCZ, including effector memory CD4+ T cells, activated CD8+ T cells, mast cells, naive CD8+ T cells, PBMC, type 17 helper cells (Th17), central memory CD8+ T cells, CD56 bright NK cells, memory B cells, and regulatory T cells. Diagnostic models constructed using LASSO regression exhibited an average area under the curve (AUC) of 0.866. Our results indicate immunological dysfunction as a factor in the development of SCZ. ASGR2, ADRM1, AHANK, S100A8, FUCA1, AKNA, GATA3, AHCYL2, and PTRH2 are the key regulatory genes of immune cells, highlighting their potential as novel therapeutic targets for SCZ.

T-BET and EOMES sustain mature human NK cell identity and antitumor function.

Since the T-box transcription factors (TFs) T-BET and EOMES are necessary for initiation of NK cell development, their ongoing requirement for mature NK cell homeostasis, function, and molecular programming remains unclear. To address this, T-BET and EOMES were deleted in unexpanded primary human NK cells using CRISPR/Cas9. Deleting these TFs compromised in vivo antitumor response of human NK cells. Mechanistically, T-BET and EOMES were required for normal NK cell proliferation and persistence in vivo. NK cells lacking T-BET and EOMES also exhibited defective responses to cytokine stimulation. Single-cell RNA-Seq revealed a specific T-box transcriptional program in human NK cells, which was rapidly lost following T-BET and EOMES deletion. Further, T-BET- and EOMES-deleted CD56bright NK cells acquired an innate lymphoid cell precursor-like (ILCP-like) profile with increased expression of the ILC-3-associated TFs RORC and AHR, revealing a role for T-box TFs in maintaining mature NK cell phenotypes and an unexpected role of suppressing alternative ILC lineages. Our study reveals the critical importance of sustained EOMES and T-BET expression to orchestrate mature NK cell function and identity.

Modification of peripheric Treg and CD56brightNK levels in RIF women after egg donation, treated with GM-CSF or placebo

Recurrent implantation failure (RIF) is defined as when implantation repeatedly failed to reach a stage recognizable by pelvic ultrasound in IVF cycle and it may be due to several causes. The GM-CSF is a cytokine promoting leukocyte growth and trophoblast development: we tested it to treat these patients in a pilot-controlled trial evaluating the modification of peripheric Treg and CD56brightNK levels after the treatment with this cytokine and in control patients affected by RIF after egg donation cycles. This study was performed on 24 RIF women after egg donation cycles. Single good quality blastocyst transfer was performed in the cycle object of this study. Patients were randomly assigned to two groups: 12 women treated with subcutaneous GM-CSF 0.3 mg/kg/daily from the day before embryo transfer to the β-hCG day, and 12 women treated with subcutaneous saline solution infusion as control. All patients were tested for Treg and CD56brightNK cell levels in blood circulation before and after treatment using flow-cytometry with specific antibodies. The two groups of patients were similar for epidemiologic characteristics, the ongoing pregnancy rate in the GM-CSF group was 83.3% whereas in the control group was 25.0% (P = 0.0123). In the study group there was a significative increase of Treg cells (P < 0.001) with respect to the levels before treatment and to control group. Instead, the levels of CD56brightNK did not show any significative variation. Our study showed that the treatment with GM-CSF increases the Treg cells in the peripheric blood.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Background: Cancer is a recognized condition of secondary immunosuppression. Lymphoma patients often show a decrease in absolute lymphocyte counts and in peripheral blood gamma-globulin levels. However, less is known about how NK cells are altered in lymphoma patients. The aim of this study was to evaluate the patterns of circulating NK cell dysfunction in lymphoma patients. Methods: We performed a cross-sectional study of patients with a recent diagnosis of nodal lymphoproliferative disorder. Patients with active anticancer treatment or steroid use were excluded. Peripheral blood samples in EDTA were analyzed by multicolor flow cytometry. A custom panel of 30 markers was applied to all samples to test for major subpopulations, maturation, and functional markers. Results were compared to healthy controls. Clinical data were obtained from the electronic database. This study was approved by the institutional IRB and Clinical Ethics Committee. Results: A total of 30 patients were examined between October 2021 and November 2022. The median age was 62 years (range 15–88) and 45.7% were female (16). Patients had the following subtypes: large B-cell lymphoma (LBCL; 9), follicular lymphoma (FL; 9), Hodgkin lymphoma (HL; 5), mantle cell lymphoma (MCL; 4), marginal zone lymphoma (MZL; 2), Waldenström macroglobulinemia (WM; 1). Most patients had advanced stage disease (20). Compared to healthy controls (n = 10), lymphoma patients showed a significant decrease in absolute NK cell counts (ANKC, 319.7 vs. 131.1 cells/mm3; p < 0.0001). MCL patients had the lowest ANKC (68.8) and Hodgkin patients the highest (165.6). Advanced stage disease correlated with lower ANKC compared to localized disease (99.85 vs. 148.9; p = ns). The pattern of maturation was altered in lymphoma patients compared to controls (p = 0.0092). Patients had a higher proportion of immature CD56-bright NK cells (4.97% vs. 2.88%) and lower levels of CD16 expression in the mature CD56-dim subpopulation (68.12% vs. 85.94%). Lymphoma patients also showed dysfunctional expression of receptors and activation markers (Figure). There was a significant increase in the levels of FAS-L, IFNg, CD49b, CD57, CD96, and CD107a, while the levels of TIGIT and NKG2D were significantly decreased. Differences in the expression of immune checkpoints (PD-1, LAG-3, TIM-3), as well as additional activating, inhibitory, and chemokine receptors were not significant. 22 of 30 patients (73.3%) achieved a complete response. All patients with ANKC above 135 cells/mm3 at diagnosis achieved sustained complete remission. The research was funded by: Fondecyt 11200805 Clínica Alemana de Santiago ID1025 Keyword: diagnostic and prognostic biomarkers No conflicts of interests pertinent to the abstract.

Tumor infiltrating natural killer cells in soft tissue sarcoma are predominantly CD56 dim: Implications for outcomes

Abstract Natural killer (NK) cells have been shown to be important mediators of anti-tumor responses, including in soft tissue sarcomas (STS). NK cells show significant heterogeneity, depending on maturation, tissue residency, and inflammatory environment. As previous studies have suggested that tumor-infiltrating NK cells (TiNKs) acquire a less cytotoxic CD56 brighttissue resident phenotype, we sought to compare blood versus tumor NK cell phenotype in STS and evaluate any association with survival. Blood and tumor from 27 STS patients undergoing surgery from 2018–2022 were collected prospectively for flow cytometry and retrospectively analyzed. 52% were female, the mean age was 59, and 74% were AJCC stage 3. Increasing absolute number of NK cells in the blood correlated with longer survival (P&amp;lt;0.005, r=0.6). As expected, CD56 dimNK cells predominated in the blood (91.5±5.8% of CD3-CD56+ lymphocytes compared to 80.1±13% in tumor, P&amp;lt;0.005). In contrast, CD56 brightcells were enriched in tumor representing 18.5±13% compared to 8.4±5.8% in blood (P&amp;lt;0.005). Although CD56 brightNK cells were approximately 2.4±3-fold higher in tumor compared to blood, CD56 dimNK cells still represented the majority of TiNKs. Higher proportions of both overall NK cells and CD56 dimNK cells in STS tumors were associated with better metastasis-free survival on Kaplan-Meier analysis (P&amp;lt;0.05). CD56 dimTiNKs had higher NKp46 expression than CD56 brights. In conclusion, both blood and intra-tumoral NK cells appear prognostic in STS. Although the proportion of CD56 brightTiNKs in STS is higher than blood the majority of TiNKs are CD56 dimconsistent with a cytotoxic phenotype. Better characterization of NK subsets in STS is likely to have translational significance.

Bioinformatic analyzes and validation of cystathionine gamma-lyase as a prognostic biomarker and related to immune infiltrates in hepatocellular carcinoma

BackgroundThe role of cystathionine γ-lyase (CTH) in the prognosis and immune invasion of hepatocellular carcinoma (HCC) remains poorly understood. MethodsIn this study, the clinical data of patients with HCC were analyzed, and the expression level of CTH was compared between HCC and normal tissues using the R package and various databases. ResultsWe found that CTH expression was significantly decreased in HCC compared with normal tissues, and its expression was associated with various clinicopathological factors, including tumor stage, gender, tumor status, residual tumor, histologic stage, race, alpha-fetoprotein (AFP), albumin, drinking, and smoking. Our results suggest that CTH might be a protective factor for the survival of patients with HCC. Further functional analysis revealed that high CTH expression was enriched in the Reactome signaling by interleukins and the Reactome neutrophil degranulation. Moreover, CTH expression was closely correlated with a variety of immune cells, including a negative correlation with the CD56 (bright) NK cells and follicular helper T cell (TFH), while a positive correlation with Th17 cells and central memory T cell (Tcm). High expression of CTH in immune cells predicted a better prognosis of HCC. Our findings further indicated Pyridoxal phosphate, l-cysteine, Carboxymethylthio-3-(3-chlorophenyl)-1,2,4-oxadiazol, 2-[(3-Hydroxy-2-Methyl-5-Phosphonooxymethyl-Pyridin-4-Ylmethyl)-Imino]-5-phosphono-pent-3-enoic acid and L-2-amino-3-butynoic acid as potential target candidate medications for HCC treatment based on CTH. ConclusionOur study suggests that CTH can serve as a biomarker to predict the prognosis and immune infiltration of HCC.

Differential sensitivity to replication stress of human NK cells

Abstract Natural killer cells are critical components of the innate immune system that kill virally infected or malignant cells. Though rare, natural killer cell deficiency (NKD) occurs when NK cell development and function are impaired and individuals with NKD are susceptible to severe and recurrent viral infections. Several gene deficiencies have been described to result in NKD, including variants in MCM4, GINS1, MCM10and GINS4, which are components of the CMG helicase. The helicase unwinds DNA during replication and is found in any actively proliferating cell. NK cells are more strongly impacted by mutational deficiencies in helicase proteins than other lymphocytes, though the mechanisms underlying this are not completely understood. NK cells from individuals with NKD as a result of helicase deficiency have increased DNA damage, cell cycle arrest, and replication stress. Here, we induced replication stress during NK or T cell specific activation by chemical methods, using aphidicolin, and genetic methods like siRNA targeting helicase proteins. We found that the CD56 brightsubset of NK cells accumulates more DNA damage and replication stress during activation than CD56 dimNK cells or activated T cells. The drug aphidicolin increases apoptosis of CD56 brightNK cells through caspase activation while simultaneously decreasing intracellular perforin expression, a protein important for killing of target cells. This effect is modeled by siRNA mediated knockdown of CMG proteins, thus linking decreased protein expression to replication stress and impaired NK cell function. These findings lend important insight into the mechanisms by which helicase deficiencies selectively affect human NK cell function and cause NK cell deficiency. NIH R01A137275

GATA2-TGF-b1 axis regulates human NK cell development

Abstract Natural killer (NK) cells, a subset of innate lymphocytes, produce proinflammatory cytokines and mediate anti-tumor cytotoxicity. GATA2 is a master transcription factor that is essential for the development of erythroid, myeloid, B, and NK cells. Patients with GATA2 haploinsufficiency lack CD56 brightNK cells (immature), with or without a reduction in the number of CD56 dimNK cells (mature). However, how GATA2 functions to establish and maintain genetic networks during the development and function of human NK cells is unknown. Here, we identify a novel GATA2-TGF-b1 axis that regulates NK cell development. We performed single-cell RNA-seq with NK cells from three GATA2 T354Mpatients and found significantly reduced expression of immediate early genes, which indicated that they are functionally-defective. We discovered a reduction in TGF-b1 transcripts and defective expression of TGF-b1 target genes in NK cells from GATA2 T354Mpatients. Using a reporter assay, we determined that GATA2 occupy to TGFB1 promoter, and this association was decreased in GATA2 T354MNK cells. ATAC-seq of GATA2 T354MNK cells indicates significantly altered chromatin accessibility. GATA2 CUT&amp;Tag-seq validated that it occupies the TGFB1 promoter region, which correlated with activation of the TGFB1 locus in human NK cells. In summary, we define a mechanism by which GATA2 controls TGF-b1 production in human NK cells and thereby regulating their development. These findings provide vital clues for developmental and functional defects of NK cells in GATA2 T354Mpatients. ASH Graduate Hematology Award (D.W.); GIRT Award from MCW-C4I (D.W.); NIH R01 AI102893 and NCI R01 CA179363 (S.M.); HRHM Program of MACC Fund (S.M.), Nicholas Family Foundation (S.M.); Gardetto Family (S.M.); MCW-Cancer Center-Large Seed Grant (S.M. and M.S.T.); MACC Fund (S.M.); Ann’s Hope Mela- noma Foundation (S.M.); and Advancing Healthier Wisconsin (S.M.)

Elevated exosome-transferrable lncRNA EPB41L4A-AS1 in CD56bright NK cells is responsible for the impaired NK function in neuroblastoma patients by suppressing cell glycolysis

NK cells are one of key immune components in neuroblastoma (NB) surveillance and eradication. Glucose metabolism as a major source of fuel for NK activation is exquisitely regulated. Our data revealed a diminished NK activation and a disproportionally augmented CD56bright subset in NB. Further study showed that NK cells in NB presented with an arrested glycolysis accompanied by an elevated expression of the long noncoding RNA (lncRNA) EPB41L4A-AS1, a known crucial participant in glycolysis regulation, in the CD56bright NK subset. The inhibitory function of lncRNA EPB41L4A-AS1 was recapitulated. Interestingly, our study demonstrated that exosomal lncRNA EPB41L4A-AS1 was transferrable from CD56bright NK to CD56dim NK and was able to quench the glycolysis of target NK. Our data demonstrated that an arrested glycolysis in patient NK cells was associated with an elevated lncRNA in CD56bright NK subset and a cross-talk between heterogeneous NK subsets was achieved by transferring metabolic inhibitory lncRNA through exosomes.

Abstract 2127: TERT C228T and KDM6A alterations are potential predictive biomarkers in non-muscle-invasive bladder cancer treated with intravesical Bacillus Calmette-Guérin instillation

Abstract Introduction: Bacillus Calmette-Guérin (BCG) is the standard of care for high-risk non-muscle-invasive bladder cancer (NMIBC) following transurethral resection. However, patients often have heterogeneous responses. Even among those who initially respond well to BCG, 10-20% relapse. Identification of reliable biomarkers predicting the efficacy of BCG remains an unmet need. En bloc resection is a novel technique representing a substantial advancement in the surgical management of NMIBC. We sought to investigate genomic and tumor microenvironmental (TME) profiles in NMIBC and explore potential predictive markers for BCG treatment following en-block resection. Methods: A total of 40 patients with high-risk NMIBC (cTis-T1N0M0) were retrospectively enrolled who underwent en bloc resection followed by BCG instillation. Surgical samples were subjected to NGS sequencing using a 520-gene panel (Burning Rock Biotech, Guangzhou) and multiplex immunofluorescence (mIF) assay. Results: The cohort had a median age of 63 years, and 80% were male. After a median follow-up of 21.8 months, 19/40 patients relapsed with a one-year relapse-free survival (RFS) rate of 57.5%. All tumors were microsatellite stable and showed a median TMB of 7.98muts/Mb. Genomic profiling revealed a high prevalence of alterations in TERT (55%), KDM6A (32.5%), KMT2D (32.5%), FGFR3(30%), PIK3CA (30%), TP53(27.5%), KMT2C (25%), and ARID1A (20%). TME analysis showed higher proportions of M1 macrophages and CD56 dim NK cells in the tumoral compartment and more intense infiltration of CD8+ T cells, exhausted CD8+T, CD56 bright NK cells, and M2 macrophages in the stromal compartment. Multivariate analysis identified TERT C228T mutation (HR=3.28 [95%CI:1.225-8.79], p=0.0181) and alteration in KDM6A (HR=2.94 [95%CI:1.040-8.29], p=0.042) as two independent factors associated with inferior RFS. Patients with concomitant TERT C228T and KDM6A alteration had the shortest RFS (median RFS:5.83months) compared with those who were free of (median RFS: NR) or harbored either one of the two alterations (median RFS:9.13months) (p=0.0022). We also found that tumoral infiltration of CD8+T cells was positively associated with RFS (HR=0.29 [95%CI:0.097-0.885], p=0.0208). Conclusion: The study comprehensively depicted the genomic and TME profiles in NMIBC and identified potential predictive biomarkers for BCG treatment. Our findings may facilitate the stratification of patients and better guide the clinical decision-making on the management of NMIBC. Citation Format: Qi-Dong Xia, Yao-Bing Chen, Jian-Xuan Sun, Chen-Qian Liu, Jin-Zhou Xu, Zhi-Peng Yao, Ye An, Meng-Yao Xu, Si-Han Zhang, Xing-Yu Zhong, Na Zeng, Si-Yang Ma, Hao-Dong He, Heng-Long Hu, Jia Hu, Yi Lu, Lin Shao, Si-Qi Li, Zheng Liu, Shao-Gang Wang. TERT C228T and KDM6A alterations are potential predictive biomarkers in non-muscle-invasive bladder cancer treated with intravesical Bacillus Calmette-Guérin instillation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2127.

Effect of mTOR Inhibition with Sirolimus on Natural Killer Cell Reconstitution in Allogeneic Stem Cell Transplantation

Sirolimus is an inhibitor of the mammalian target of rapamycin (mTOR) and is emerging as a promising component of graft-versus-host disease (GVHD) prophylaxis regimens in the context of allogeneic hematopoietic stem cell transplantation (HSCT). Multiple studies have explored the clinical benefits of adding sirolimus to GVHD prophylaxis, however detailed immunological studies have not yet been carried out in this context. Mechanistically, mTOR is at the center of metabolic regulation in T- and NK cells and is critical for their differentiation to mature effector cells. Therefore, close evaluation of the inhibition of mTOR in the context of immune reconstitution post HSCT is warranted. To study the effect of sirolimus on the immune reconstitution using a biobank of longitudinal samples from patients receiving either tacrolimus/sirolimus (TAC/SIR) compared to cyclosporin A/methotrexate (CSA/MTX) as conventional GVHD prophylaxis. Healthy donor controls, donor graft material, and samples from 28 patients (14 TAC/SIR, 14 CSA/MTX) at 3-4 weeks and 34-39 weeks post HSCT were collected. Multi-color flow cytometry was used to carry out a broad immune cell mapping with a particular focus on NK cells. NK cell proliferation was evaluated over a 6-day in vitro homeostatic proliferation protocol. Furthermore, in vitro NK cell responses to cytokine stimulation or tumor cells were evaluated. Systems-level assessment of the immune repertoire revealed a deep and prolonged suppression (week 34-39 after HSCT) of the naïve CD4 T cell compartment with a relative sparing of regulatory T cells and an enrichment of CD69+Ki-67+HLA-DR+ CD8 T cells, independent of the type of GVHD prophylaxis. Early after transplantation (week 3-4), while patients were still on TAC/SIR or CSA/MTX, we found a relative increase in less differentiated CD56bright NK cells and NKG2A+CD57-KIR- CD56dim NK cells and a distinct loss of CD16 and DNAM-1 expression. Both regimens led to suppressed proliferative responses ex vivo and functional impairment with preferential loss of cytokine responsiveness and IFN-γ production. Patients that received TAC/SIR as GVHD prophylaxis showed delayed NK cell reconstitution with lower overall NK cell counts, fewer CD56brights and NKG2A+ CD56dim NK cells. Treatment with Sirolimus containing regimens generated similar immune cell profiles as conventional prophylaxis. However, the NK cell compartment seemed to be composed of slightly more mature NK cells. These effects were also present after GVHD prophylaxis end, suggesting that mTOR-inhibition with sirolimus leaves a lasting imprint on homeostatic proliferation and NK cell reconstitution following HSCT.

Immature natural killer cells promote progression of triple-negative breast cancer.

Natural killer (NK) cells are cytotoxic lymphocytes that accumulate within the tumor microenvironment and are generally considered to be antitumorigenic. Using single-cell RNA sequencing and functional analysis of multiple triple-negative breast cancer (TNBC) and basal tumor samples, we observed a unique subcluster of Socs3highCD11b-CD27- immature NK cells that were present only in TNBC samples. These tumor-infiltrating NK cells expressed a reduced cytotoxic granzyme signature and, in mice, were responsible for activating cancer stem cells through Wnt signaling. NK cell-mediated activation of these cancer stem cells subsequently enhanced tumor progression in mice, whereas depletion of NK cells or Wnt ligand secretion from NK cells by LGK-974 decreased tumor progression. In addition, NK cell depletion or inhibition of their function improved anti-programmed cell death ligand 1 (PD-L1) antibody or chemotherapy response in mice with TNBC. Furthermore, tumor samples from patients with TNBC and non-TNBC revealed that increased numbers of CD56bright NK cells were present in TNBC tumors and were correlated to poor overall survival in patients with TNBC. Together, our findings identify a population of protumorigenic NK cells that may be exploited for both diagnostic and therapeutic strategies to improve outcomes for patients with TNBC.

S2-2 - Decidual CXCR4+ CD56bright NK cells as a novel NK subset in maternal–fetal immune tolerance to alleviate early pregnancy failure

S2-2 - Decidual CXCR4+ CD56bright NK cells as a novel NK subset in maternal–fetal immune tolerance to alleviate early pregnancy failure

Bone marrow‐derived mesenchymal stem cells inhibit NK cell function via Tim‐3/galectin‐9 in multiple myeloma patients

Bone marrow‐derived mesenchymal stem cells inhibit NK cell function via Tim‐3/galectin‐9 in multiple myeloma patients

The co-inhibitory receptor TIGIT regulates NK cell function and is upregulated in human intrahepatic CD56bright NK cells.

The crosstalk between NK cells and their surrounding environment is enabled through activating and inhibitory receptors, which tightly control NK cell activity. The co-inhibitory receptor TIGIT decreases NK cell cytotoxicity and is involved in NK cell exhaustion, but has also been associated with liver regeneration, highlighting that the contribution of human intrahepatic CD56bright NK cells in regulating tissue homeostasis remains incompletely understood. A targeted single-cell mRNA analysis revealed distinct transcriptional differences between matched human peripheral blood and intrahepatic CD56bright NK cells. Multiparameter flow cytometry identified a cluster of intrahepatic NK cells with overlapping high expression of CD56, CD69, CXCR6, TIGIT and CD96. Intrahepatic CD56bright NK cells also expressed significantly higher protein surface levels of TIGIT, and significantly lower levels of DNAM-1 compared to matched peripheral blood CD56bright NK cells. TIGIT+ CD56bright NK cells showed diminished degranulation and TNF-α production following stimulation. Co-incubation of peripheral blood CD56bright NK cells with human hepatoma cells or primary human hepatocyte organoids resulted in migration of NK cells into hepatocyte organoids and upregulation of TIGIT and downregulation of DNAM-1 expression, in line with the phenotype of intrahepatic CD56bright NK cells. Intrahepatic CD56bright NK cells represent a transcriptionally, phenotypically, and functionally distinct population of NK cells that expresses higher levels of TIGIT and lower levels of DNAM-1 than matched peripheral blood CD56bright NK cells. Increased expression of inhibitory receptors by NK cells within the liver environment can contribute to tissue homeostasis and reduction of liver inflammation.

P034 A common IL2RA polymorphism alters natural killer cell immunophenotype and function in Crohn’s disease, with implications for IL-2 based therapy

Abstract Background The single nucleotide polymorphism (SNP) rs61839660 lies within the IL2RA (CD25) intronic enhancer and has been identified as a causal variant in Crohn’s disease (CD), with a heterozygote frequency of 16.8% in a European population. CD25 is the high-affinity receptor for IL-2, and is constitutively expressed on regulatory T cells (Tregs). Low-dose IL-2 (LD-IL2) is under investigation in IBD, under the premise that it will expand a group of tolerising Tregs. However, finding a therapeutic dose which activates Tregs without activating effector T cells (Teffs) has proved challenging and activation of CD56dim NK cells has been linked to adverse events in trial subjects. We have demonstrated that the rs61839660 risk (T) allele carriers exhibit higher CD4+ T cell CD25 expression, enhanced pSTAT5 activation on stimulation with IL-2, and greater Teff release of pro-inflammatory cytokines. We sought to understand the impact of the risk allele on NK cell immunophenotype and function. Methods We recruited CD patients homozygous major allele (CC), or heterozygous (CT) at the rs61839660 locus. We extracted peripheral blood mononuclear cells and flow-sorted CD56dim (cytotoxic) and CD56bright (regulatory) NK subsets. Cells were stimulated with IL-2, then stained for intracellular pSTAT5. To assess cytotoxicity, NK cells were rested in media either with or without IL-2, before plating with CFSE-labelled K562 target cells. The proportion of K562 cells positive for dead cell marker was assessed for each condition. Results There was no difference in CD phenotype or severity between groups, in terms of age at diagnosis, sex distribution, presence of perianal disease or the proportion requiring surgery. CD25 expression was significantly enhanced on CD56Bright NK cells in CT subjects compared to CC subjects (1b). Enhanced CD25 expression was also seen in CD56Dim NK cells, though this did not reach statistical significance (1a). The concentration of IL-2 required to activate 50% intracellular STAT5 was lower in CT subjects’ CD56Bright NK cells compared to those from CC subjects (21.5IU/ml vs. 132.4IU/ml, p=0.039). The cytotoxicity of CT subjects’ CD56dim NK cells was significantly enhanced following exposure to IL-2, compared to CC subjects (1c). Conclusion Our findings suggest that risk (T) allele carriers have enhanced responsiveness to IL-2 signalling in NK cells, mediated by increased expression of CD25. We hypothesise that these subjects would be at greater risk of adverse events on exposure to LD-IL2, through enhanced CD56Dim NK cytotoxicity. Our results suggest that screening of subjects entering trials of IL-2-based therapy for the rs61839660 risk variant should be considered, as the threshold for adverse events in these subjects may be lower.

DOP29 Single cell analysis of Crohn’s disease fistula; comparison of different locations

Abstract Background A common complication of Crohn’s disease(CD) are perianal fistulae, highly impacting the quality of life in these patients. The pathogenesis of these fistulas is incompletely understood. Treatment is often given based on knowledge of disease processes in the inflamed intestine itself, but whether the immune activity in the fistula tract is similar remains unknown. Full characterization of the intestinal mucosa versus the fistula tract itself may reveal immunological differences between the two, and generate leads for both development of new interventional options as well as allow better stratification of patients. Methods Matched biopsies were obtained from the rectal mucosa, the internal opening of the fistula and the tract itself. A total of 30 patients were included (20 CD; 10 non-IBD patients). Tissues were processed to cell suspensions and selected for live CD66b- cells. Single cell RNASeq analysis was performed using 10x Chromium. In total, 111.955 immune cells were annotated and used for analysis. Results T cells comprised the largest cluster of immune cells, which was subclustered into 19 clusters. Both the internal opening and the fistula tracts contained elevated proportions of effector memory and cycling T cells. Conversely, the rectum contained more central and tissue resident memory cells. T cells expressing IL-22, which were previously described in fistula were detected in considerable number in the rectum and internal opening, but were scarce in the fistula tract itself. These cells were clearly distinct from the IL17A producing subset, and IL17F expressing cells and mainly found in the fistula tracts. Only the tract contained a clear subset of CXCL13 expressing T cells, suggesting follicular helper T cells. Presence of these cells was strongly correlated to the presence of lymphoid inducer cells as well as IgG producing B cells rather than the IgA subset found in the rectum. Clusters of myeloid cells were largely derived from the fistula tracts. Subclustering into 10 clusters indicated a shift from anti-inflammatory to pro-inflammatory macrophages in the tracts compared to the rectal mucosa. Finally, a striking difference in NK cells subsets was observed, with significantly more CD56bright NK cells present in the rectal samples while the internal opening and the tracts were comparable. Conclusion Cellular composition and activity of the immune cell compartment differs considerably between the rectum, the internal opening of the fistula and the tract. Subsequently, therapy targeted at processes involved in mucosal inflammation may not actually target the fistula itself, which may explain the low success rate in fistula resolution. Careful analysis of the fistula may help to identify targets useful in the treatment.

Human pegivirus-1 replication influences NK cell reconstitution after allogeneic haematopoietic stem cell transplantation.

Human pegivirus-1 (HPgV-1) is a so-called commensal virus for which no known associated organ disease has been found to date. Yet, it affects immune-reconstitution as previously studied in the HIV population, in whom active co-infection with HPgV-1 can modulate T and NK cell activation and differentiation leading to a protective effect against the evolution of the disease. Little is known on the effect of HPgV-1 on immune-reconstitution in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients, a patient population in which we and others have previously reported high prevalence of HPgV-1 replication. The aim of this study was to compare the immune reconstitution after allo-HSCT among HPgV-1-viremic and HPgV-1-non-viremic patients. Within a cohort study of 40 allo-HSCT patients, 20 allo-HSCT recipients positive in plasma sample for HPgV-1 by rRT-PCR during the first year (1, 3, 6, 12 months) after transplantation were matched with 20 allo-HSCT recipients negative for HPgV-1. T and NK cell reconstitution was monitored by flow cytometry in peripheral blood samples from allo-HSCT recipients at the same time points. We observed no significant difference in the absolute number and subsets proportions of CD4 and CD8 T cells between patient groups at any analysed timepoint. We observed a significantly higher absolute number of NK cells at 3 months among HPgV-1-viremic patients. Immunophenotypic analysis showed a significantly higher proportion of CD56bright NK cells mirrored by a reduced percentage of CD56dim NK cells in HPgV-1-positive patients during the first 6 months after allo-HSCT. At 6 months post-allo-HSCT, NK cell phenotype significantly differed depending on HPgV-1, HPgV-1-viremic patients displaying NK cells with lower CD16 and CD57 expression compared with HPgV-1-negative patients. In accordance with their less differentiated phenotype, we detected a significantly reduced expression of granzyme B in NK cells in HPgV-1-viremic patients at 6 months. Our study shows that HPgV-1-viremic allo-HSCT recipients displayed an impaired NK cell, but not T cell, immune-reconstitution compared with HPgV-1-non-viremic patients, revealing for the first time a potential association between replication of the non-pathogenic HPgV-1 virus and immunomodulation after allo-HSCT.

Regulatory NK cells in autoimmune disease.

NK cells are defined as the major components of the immunological network which exerts defense against tumors and viral infections as well as regulation of innate and adaptive immunity, shaped through interaction with other cells like T cells. According to the surface markers, NK cells can be divided into CD56dim NK and CD56bright NK subsets. CD56bright NK cells usually are known as regulatory NK cells. Once the immune system loses its self-tolerance, autoimmune diseases develop. NK cells and their subsets can be altered during autoimmune diseases, indicative of their prominent regulatory roles and even pathological and protective functions in autoimmune disorders. In this regard, activation of CD56bright NK cells can suppress activated autologous CD4+ T cells and subsequently prevent the initiation of autoimmunity. In this review article, we summarize the roles of regulatory NK cells in autoimmune disease occurrence which needs more research to uncover their exact related mechanism. It seems that targeting NK cells can be a promising therapeutic platform against autoimmune diseases.

KLRF1, a novel marker of CD56bright NK cells, predicts improved survival for patients with locally advanced bladder cancer.

Bladder tumor-infiltrating CD56bright NK cells are more tumor cytotoxic than their CD56dim counterparts. Identification of NK cell subsets is labor-intensive and has limited utility in the clinical setting. Here, we sought to identify a surrogate marker of bladder CD56bright NK cells and to test its prognostic significance. CD56bright and CD56dim NK cells were characterized with the multiparametric flow (n=20) and mass cytometry (n=21) in human bladder tumors. Transcriptome data from bladder tumors (n=351) profiled by The Cancer Genome Atlas (TCGA) were analyzed. The expression levels of individual markers in intratumoral CD56bright and CD56dim NK cells were visualized in tSNE plots. Expressions of activation markers were also compared between Killer Cell Lectin-Like Receptor Subfamily F Member 1 (KLRF1)+ and KLRF1- NK cells. Intratumoral CD56bright NK cells displayed a more activated phenotype compared to the CD56dim subset. Multiple intratumoral cell types expressed CD56, including bladder tumor cells and nonspecific intratumoral CD56 expression was associated with worse patient survival. Thus, an alternative to CD56 as a marker of CD56bright NK cells was sought. The activation receptor KLRF1 was significantly increased on CD56bright but not on CD56dim NK cells. Intratumoral KLRF1+ NK cells were more activated and expressed higher levels of activation molecules compared with KLRF1- NK cells, analogous to the distinct effector function of NK cells across CD56 expression. High intratumoral KLRF1 was associated with improved recurrence-free survival (hazard ratio [HR] 0.53, p=0.01), cancer-specific survival (HR 0.47, p=0.02), and overall survival (HR 0.54, p=0.02) on multivariable analyses that adjusted for clinical and pathologic variables. KLRF1 is a promising prognostic marker in bladder cancer and may guide treatment decisions upon validation.