Natural Killer Cell Subsets Research Articles

Decreased exercise-induced natural killer cell redistribution in multiple sclerosis

BackgroundExercise may have beneficial effects in MS, remaining controversial its possible disease-modifying effects and which mechanisms might be involved. We evaluated whether exercise-induced lymphocyte redistribution differ in MS patients as compared to controls. MethodsExercise was assessed in 12 relapsing-remitting MS patients and 11 controls in a cycle ergometer, obtaining blood samples before exercise, at maximal exercise capacity (T1), and after resting (T2). Peripheral lymphocytes were evaluated by flow cytometry, assessing chemokine receptor expression to study cell trafficking properties. ResultsLymphocyte subsets in all cases increased after exercise and decreased at resting. However, total natural killer (NK) cells in patients as compared to controls had a lower exercise-induced redeployment at T1 (696 ± 581 cells/µL vs.1502 ± 641 cells/µL, p < 0.01). Evaluating NK cell subsets, CD56bright NK cells numbers decreased in peripheral blood in MS patients after resting (T2), contrasting with values remaining above baseline in healthy controls. NK cells mobilized after exercise at T1 in controls, as compared to patients, had a higher CX3CR1 expression (1402 ± 564/µL vs. 615 ± 548 cell//µL, p < 0.01). ConclusionExercise-induced redeployment of NK cells may be reduced in MS patients, as well as their migration capabilities, pointing to potential immunological mechanisms to be enhanced by exercise training programs.

Early recovery of natural killer cells post T-cell depleted allogeneic stem cell transplantation using alemtuzumab “in the bag”

BackgroundAllogeneic stem cell transplantation (SCT) is a critical therapy for haematological malignancy but may lead to acute and chronic graft versus host disease (GvHD). T-cell depletion with alemtuzumab, either in vivo or ex vivo, reduces the incidence of GvHD but is a risk factor for disease relapse and poor immune reconstitution. Natural killer (NK) cells are the first lymphocytes to recover. Classical NK cells make up >90% of the normal circulating population and can directly kill neoplastic or virally infected cells while the regulatory subset makes up <10%, secretes cytokines and is not cytotoxic. The recovery and balance of these subsets post SCT remains controversial, with most studies analysing patients who received unmanipulated grafts and in vivo immunosuppression. ObjectiveThe aim was to assess the early recovery of NK cells in 18 consecutive patients receiving ex vivo T-cell depleted SCT and to compare the results to 25 individuals receiving haploidentical non-T cell depleted grafts. MethodsAll patients received myeloablative conditioning. After stem cell collection, the stem cells of the T cell depleted group were treated “in the bag” with alemtuzumab (CAMPATH 1H) at a concentration of 1mg/108 mononuclear cells and thereafter immediately infused. For those receiving non-T cell depleted grafts, GvHD prophylaxis was with post infusion therapeutic doses of cyclophosphamide. Blood samples were collected at days 21, 28 and 90. Complete blood counts were performed on an automated analyser while lymphocyte and NK subsets were examined using multiparameter flowcytometry. NK cells were defined as lymphocytes which were CD3-/CD56+. The classical subset was recognised as CD56dim/CD16+ while the regulatory population as CD56bright/CD16-. The results for both transplant types were compared at all time points using SPSS v8 statistical software. ResultsThe recovery of lymphocytes was slow in both groups. Those receiving non-T cell depleted grafts had significantly higher T cell counts at day 21 and 28 when compared to the T cell depleted group (P < 0.05). In contrast, NK cells in the ex vivo T-cell depleted patients recovered rapidly and by day 21 was no different to normal (p > 0.05), while the non-T cell depleted group had significantly decreased numbers (p < 0.001), only recovering at day 90. Both groups had abnormal NK cell subset ratios with significantly elevated percentages of regulatory cells (p < 0.05). However, significant differences were observed between the two groups with those receiving T cell depleted grafts having lower percentages of regulatory cells as well as higher numbers of classical NK cells at day 21 and 28 (p < 0.01). ConclusionThis study of ex vivo T-cell depleted SCT's demonstrates that NK cells recover quicker when compared to those receiving unfractionated grafts. These results may have implications for GvHD and the GvL effect which warrants further study.

Natural Killer Cell Subsets in Tumor Draining Lymph Nodes of Patients with Bladder Cancer and Their Clinical Implications.

Natural killer (NK) cells are crucial innate components in anti-tumor immunity. However, the clinical impacts and their phenotypes in bladder cancer (BC) remain unclear. To assess the clinical significance of NK cell subsets in tumor-draining lymph nodes of patients with BC. In a cross-sectional study, pelvic lymph nodes were obtained from 49 untreated patients with BC. Mononuclear cells were isolated and immunophenotyped using CD3, CD56, CD16, CD27, and CD11b markers. NK cells were then classified based on their expression patterns of CD56/CD16 (conventional) and CD27/CD11b (new). On average, NK cells constituted 2.99±1.44% of the total lymphocytes in the draining lymph node of patients with BC. The CD56dim and regulatory NK subsets (CD27+CD11b+/-) were the predominant old and new NK, respectively. The NK cells significantly increased in patients with at least one involved node (LN+) compared with those with free nodes (LN-; p=0.022). Conversely, CD56dimCD16- subset significantly decreased in higher stages (p=0.032) and in tumors with muscle invasion (p=0.038). Significant variations were also observed in different T-stages (p<0.05). Regarding new classification, the frequency of CD11b+ regulatory NK cells was significantly lower in node-positive patients (p=0.025). These findings emphasize the dynamic nature of NK cell subsets in bladder cancer and their potential relevance in disease progression and management, suggesting potential implications for therapeutic strategies targeting these specific subsets.

Camrelizumab, chemotherapy and apatinib in the neoadjuvant treatment of resectable oesophageal squamous cell carcinoma: a single-arm phase 2 trial

In resectable oesophageal squamous cell carcinoma (ESCC), the efficacy of camrelizumab combined with chemotherapy and apatinib followed by minimally invasive oesophagectomy is not clear. We aimed to fill this knowledge gap. This investigator-initiated, single-arm, prospective, phase 2 trial was performed at the Second Affiliated Hospital of Zhejiang University, China. Patients (aged 18-75 years) who were histologically or cytologically diagnosed with ESCC were deemed suitable to participate in this trial. Patients received 2-3 cycles of neoadjuvant therapy with camrelizumab, nedaplatin, albumin paclitaxel, and apatinib; each cycle was repeated every 14 days. Surgery occurred 4-6 weeks after the last neoadjuvant treatment cycle. The primary outcome was the pathological complete response (PCR) rate of the tumour and lymph nodes. The changes in the peripheral blood immunoprofile among patients without PCR (ie, non-PCR [NPCR]) and with PCR were assessed by mass cytometry. This study was registered with ClinicalTrials.gov, NCT04666090. 42 patients were enrolled between November 23, 2020 and December 31, 2022. The disease control rate was 100.0% (95% CI, 91.6-100%), and the objective response rate was 83.3% (95% CI, 68.6-93.0%). Six (14.3%) patients experienced grade 3 adverse events. The most common were white blood cell count decrease (31.0%), alopecia (81.0%), asthenia (38.1%), and reactive cutaneous capillary endothelial proliferation (35.7%). 41 patients received minimally invasive oesophagectomy; all 41patients achieved R0 resection, and 18 (43.9%, 95% CI, 28.5-60.3%) patients achieved PCR. The median follow-up was 23 months and the 2-year survival rate was 85.9%. T-cell subsets in both the PCR and NPCR groups exhibited consistency in response to neoadjuvant therapy. In contrast, some of natural killer (NK) cells (NK-C03, NK-C11), B cells (B-C06) and monocytes (M-C05), exhibited significant differences between the PCR and NPCR groups before neoadjuvant therapy. M-C06 had a significant difference in the PCR group and NPCR group after neoadjuvant therapy. NK-C12 and B-C15 showed significant differences both before and after neoadjuvant therapy. The application of camrelizumab, chemotherapy and apatinib in the neoadjuvant setting for locally advanced ESCC has shown promising antitumour activity and an acceptable safety profile in this single-arm study. In the neoadjuvant setting, NK cell, B cell, and monocyte subsets exhibited greater predictive power for immunotherapy responsiveness than T-cell subsets. Longer follow-up to assess survival outcomes and a phase 3 randomised trial are needed to further evaluate the proposed treatment. The China Anti-Cancer Association and the "Leading Goose" Research and Development Project of Zhejiang Province.

Natural killer cell subsets and their functional molecules in peripheral blood of the patients with breast cancer.

Natural killer (NK) cells, CD3- lymphocytes, are critical players in cancer immune surveillance. This study aimed to assess two types of CD3- NK cell classifications (subsets), that is, convectional subsets (based on CD56 and CD16 expression) and new subsets (based on CD56, CD27, and CD11b expression), and their functional molecules in the peripheral blood of patients with breast cancer (BC) in comparison with healthy donors (HDs). Thirty untreated females with BC and 20 age-matched healthy women were enrolled. Peripheral blood samples were collected and directly incubated with fluorochrome-conjugated antibodies against CD3, CD56, CD16, CD27, CD11b, CD96, NKG2C, NKG2D, NKp44, CXCR3, perforin, and granzyme B. Red blood cells were then lysed using lysing solution, and the stained cells were acquired on four-color flow cytometer. Our results indicated 15% of lymphocytes in peripheral blood of patients with BC and HDs had NK cells phenotype. However, the frequency of total NK cells (CD3-CD56+), and NK subsets (based on conventional and new classifications) was not significantly different between patients and HDs. We observed mean fluorescent intensity (MFI) of CXCR3 in total NK cells (p = .02) and the conventional cytotoxic (CD3-CD56dim CD16+) NK cells (p = .03) were significantly elevated in the patients with BC compared to HDs. Despite this, the MFI of granzyme B expression in conventional regulatory (CD3-CD56brightCD16- /+) NK cells and CD3-CD56-CD16+ NK cells (p = .03 and p = .004, respectively) in the patients was lower than healthy subjects. The higher expression of chemokine receptor CXCR3 on total NK cells in patients with BC may be associated with increased chemotaxis-related NK cell infiltration. However, lower expression of granzyme B in conventional regulatory NK cells and CD3-CD56-CD16+ NK cells in the patients compared to HDs suggests reduced cytotoxic activity of the NK cells in BC. These results might demonstrate accumulating NK subsets with a dysfunctional phenotype in the peripheral blood of patients with BC.

FcαRI (CD89) is upregulated on subsets of mucosal and circulating NK cells and regulates IgA-class specific signaling and functions

Immunoglobulin A (IgA) is the predominant mucosal antibody class with both anti- and pro-inflammatory roles [1–3]. However, the specific role of the IgA receptor CD89, expressed by a subset of natural killer (NK) cells, is poorly explored. We found that CD89 protein expression on circulating NK cells is infrequent in humans and rhesus macaques, but transcriptomic analysis showed ubiquitous CD89 expression, suggesting an inducible phenotype. Interestingly, CD89+ NK cells were more frequent in cord blood and mucosae, indicating a putative IgA-mediated NK cell function in the mucosae and infant immune system. CD89+ NK cells signaled through upregulated CD3ζ, SYK, ZAP70, and SLAMF1, but also showed high expression of inhibitory receptors such as KLRG1 and reduced activating NKp46 and NKp30. CD89-based activation or ADCC with monomeric IgA1 reduced NK cell functions, while ADCC with combinations of IgG and IgA2 was enhanced compared to IgG alone. These data suggest that functional CD89+ NK cells survey mucosal sites, but CD89 likely serves as regulatory receptor which can be further modulated depending on IgA and IgG subclass. Although the full functional niche of CD89+ NK cells remains unexplored, these intriguing data suggest the CD89 axis could represent a novel immunotherapeutic target in the mucosae or early life.

Single-cell transcriptomics reveals comprehensive microenvironment and highlights the dysfuntional state of NK cells in endometrioid carcinoma.

Endometrioid endometrial cancer (EEC) is one of the most common gynecologic malignancies. The interaction between cancer cells and the cells in the tumor microenvironment (TME) plays a crucial role in determining disease progression and response to treatment. To better understand the diversity in the TME of ECC, we conducted a comprehensive analysis using single-cell RNA sequencing across 21 samples, including 16 ECC and 5 adjacent normal tissues. We primarily focused on tumor-infiltrating natural killer (NK) cells and their cell-cell interactions with other immune cell types. We identified a CD56dim_DNAJB1 NK cells subset, which had low cytotoxic capability and high stress levels, suggesting a dysfunctional state. This subset showed strong interactions with tumor-associated macrophages through several ligand-receptor pairs. Additionally, we observed that tumor-infiltrating LAMP3+ dendritic cells may inhibit CD8+ T cells or attract regulatory T cells to the tumor area. These dendritic cells also had impaired activation effects on NK cells within the TME. Our study provides valuable insights into the role of NK cells in cancer immunity and highlights the potential of targeting specific NK cell subsets for therapeutic purposes.

Abstract 1190: NK cell subsets as potential correlates of antitumor immunity in HPV+ cancers

Abstract High-risk type human papillomaviruses (HPV) are associated with genital and oral cancers, and the incidence of head and neck squamous cell cancers is fast increasing in the USA and worldwide. Survival rates for patients with locally advanced disease are poor and variable after standard of care (SOC) chemoradiation treatment (CRT). Identifying the antitumor host immune mediators important for treatment response and designing strategies to promote them are essential for improving clinical outcome. Antitumor immunity comprises of adaptive and innate immune effectors. The immediate innate immune response by natural killer (NK) cells is a critical component for antitumor efficacy. The effector function of NK cells is modulated by various receptors via a wide array of activation or inhibitory signals. Among these receptors is HLA-DR, a recognized activation marker on CD8 T and NK cells. Literature studies refer to HLA-DR+ NK cells as pre-mNK. Preclinical data demonstrated therapeutic vaccine mediated induction of pre-mNK equivalent to contribute to tumor-free long-term survival. In our studies with clinical samples from HPV+ cancer patients, we’ve observed a dysfunctional phenotype of circulating pre-mNK when compared to healthy donors, demonstrated by flow cytometry methods. The correlates for dysfunction include increased PD-1 expression, a known inhibitory receptor, and reduced CD16, an NK receptor for Antibody Dependent Cellular Cytotoxicity (ADCC). Further, we observed circulating pre-mNK cells in HPV+ head and neck patients gain functionality post-treatment, as shown by significant increases in granzyme B and CD16, both known contributors for NK cytotoxicity. In cervical cancer patients, we had the opportunity to analyze the tumor microenvironment (TME). Interestingly, we found a significant increased frequency of cytotoxic pre-mNK cells, shown by granzyme B, in the TME that was not present in circulation. Overall, pre-mNK represent a uniquely activated immune subset for antiviral and antitumor immunity. Citation Format: Madison O'Hara, Jagannadha Sastry. NK cell subsets as potential correlates of antitumor immunity in HPV+ cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1190.

The central role of natural killer cells in mediating acute myocarditis after mRNA COVID-19 vaccination

Vaccine-related acute myocarditis is recognized as a rare and specific vaccine complication following mRNA-based COVID-19 vaccinations. The precise mechanisms remain unclear. We hypothesized that natural killer (NK) cells play a central role in its pathogenesis. Samples from 60 adolescents with vaccine-related myocarditis were analyzed, including pro-inflammatory cytokines, cardiac troponin T, genotyping, and immunophenotyping of the corresponding activation subsets of NK cells, monocytes, and Tcells. Results were compared with samples from 10 vaccinated individuals without myocarditis and 10 healthy controls. Phenotypically, high levels of serum cytokines pivotal for NK cells, including interleukin-1β (IL-1β), interferon α2 (IFN-α2), IL-12, and IFN-γ, were observed in post-vaccination patients with myocarditis, who also had high percentage of CD57+ NK cells in blood, which in turn correlated positively with elevated levels of cardiac troponin T. Abundance of the CD57+ NK subset was particularly prominent in malesand in those after the second dose of vaccination. Genotypically, killer cell immunoglobulin-like receptor (KIR) KIR2DL5B(-)/KIR2DS3(+)/KIR2DS5(-)/KIR2DS4del(+) was a risk haplotype, in addition to single-nucleotide polymorphisms related to the NK cell-specific expression quantitative trait loci DNAM-1 and FuT11, which also correlated with cardiac troponin T levels in post-vaccination patients with myocarditis. Collectively, these data suggest that NK cell activation by mRNA COVID-19 vaccine contributed to the pathogenesis of acute myocarditis in genetically and epidemiologically vulnerable subjects. This work was funded by the Hong Kong Collaborative Research Fund (CRF) 2020/21 and the CRF Coronavirus and Novel Infectious Diseases Research Exercises (reference no. C7149-20G).

Abstract 5786: Epstein-Barr virus nuclear antigen 1 (EBNA1)-targeting probes stimulate interferon-β production by nasopharyngeal carcinoma (NPC) cells to enhance the natural killer cell-mediated cytotoxicity against NPC

Abstract Introduction: The prevailing histologic subtype of nasopharyngeal carcinoma (NPC) in the endemic regions is non-keratinizing carcinoma which shows almost consistent association with latent infection by Epstein-Barr virus (EBV). Previously our group developed a series of Epstein-Barr virus nuclear antigen 1 (EBNA1)-targeting probes, which can disrupt the EBV latency maintained by EBNA1, and such lytic induction could alert the immune cells. Methods: Natural killer (NK) cells of the innate immunity play a significant role in controlling EBV infection. In this study, we investigated whether our EBNA1 probes (ZRL5P4 &amp; L2P4) could activate NK cells to eliminate NPC. Results: Studies of clinical specimens indicated that tumor infiltration of the cytotoxic NK cell subset is a favorable prognostic marker for NPC patients. Furthermore, the cytotoxicity of circulating NK cells derived from NPC patients is equally well the cells from healthy individuals. If those patients’ NK cells can be attracted to infiltrate into the tumors, the tumor burden should be relieved. Indeed, the NPC xenograft with the ZRL5P4 treatment showed heavy mouse NK cell infiltration and tumor size reduction. The essential role of those mouse NK cells was demonstrated. Next, we showed that ZRL5P4 could induce the production of a soluble factor by NPC cells to stimulate the NK cell cytotoxicity. Such NK cell activity was verified in a metastasis NPC model. Mechanistically, the EBNA1 probe treatment could induce the expression of EBV early lytic gene Rta and EBNA1 itself. Both Rta and EBNA1 are known transcription factors to drive the expression of LMP1, the NF-κB signaling was then activated, which turned on the production of the well-known NK cell activation cytokine IFN-β. Conclusion: Taken together, our results demonstrated that our EBNA1 probes can mobilize NK cells to the tumor sites and activate their anti-tumor activity via the EBV reactivation and stimulation of IFN-β production. Citation Format: Luo Chen, Xiao Han Liu, Hei Tung Yuen, William C. Cho, Ka-Leung Wong, Hong Lok Lung. Epstein-Barr virus nuclear antigen 1 (EBNA1)-targeting probes stimulate interferon-β production by nasopharyngeal carcinoma (NPC) cells to enhance the natural killer cell-mediated cytotoxicity against NPC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5786.

Ozanimod-mediated remission in experimental autoimmune encephalomyelitis is associated with enhanced activity of CNS CD27low/- NK cell subset.

Ozanimod (RPC1063) is an immunomodulator that has been recently approved by the FDA (2020) for the treatment of relapsing-remitting multiple sclerosis (RRMS). It is a selective agonist of the sphingosine-1-phophate receptors 1 and 5, expressed on naïve and central memory T and B cells, as well as natural killer (NK) cells, and is involved in lymphocyte trafficking. Oral administration of ozanimod was reported to result in rapid and reversible reduction in circulating lymphocytes in multiple sclerosis (MS) patients, however, only minimal effect on NK cells was observed. In this study, we sought to investigate the effect of ozanimod on NK cells and assess whether they play any role in ozanimod-induced remission in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. Active EAE induction was done in C57BL/6 female mice, followed by daily oral treatment with ozanimod (0.6mg/kg) starting at disease onset (score 1). Flow cytometry of blood and CNS was performed 24 hours after the last oral dose of ozanimod treatment in diseased mice. Histological analysis of lumbar spinal cord was performed for evaluating the level of inflammation and demyelination. Depletion of peripheral NK cells was done using anti-NK1.1 mouse antibody (mAb) at day 5 post-EAE induction. Ozanimod was effective in reducing the clinical severity of EAE and reducing the percentage of autoreactive CD4+ and CD8+ T cells along with significant inhibition of lymphocyte infiltration into the spinal cord, accompanied by reversed demyelination. Furthermore, ozanimod treatment resulted in a significant increase in the frequency of total NK cells in the blood and CNS along with upregulation of the activating receptor NKG2D on CD27low/- NK cell subset in the CNS. The effectiveness of ozanimod treatment in inhibiting the progression of the disease was reduced when NK cells were depleted using anti-NK1.1 mAb. The current study demonstrated that ozanimod treatment significantly improved clinical symptoms in EAE mice. Ozanimod and anti-NK1.1 mAb appear to function in opposition to one another. Collectively, our data suggest that ozanimod-mediated remission is associated with an increased percentage of total NK cells and CD27low/- NK cells expressing the activating receptor, NKG2D in the CNS.

Distinct disease-modifying therapies are associated with different blood immune cell profiles in people with relapsing-remitting multiple sclerosis

Disease modifying therapies (DMTs) used for treating people with relapsing-remitting multiple sclerosis (pwRRMS) target the immune system by different mechanisms of action. However, there is a lack of a comprehensive assessment of their effects on the immune system in comparison to treatment-naïve pwRRMS. Herein, we evaluated the numbers of circulating B cells, CD4+ and CD8+ T cells, regulatory T cells (Tregs), natural killer (NK) cells and NKT cells, and their subsets, in pwRRMS who were treatment-naïve or treated with different DMTs. Compared to treatment-naïve pwRRMS, common and divergent effects on immune system cells were observed on pwRRMS treated with different DMTs, with no consistent pattern across all therapies in any of the cell populations analysed. PwRRMS treated with fingolimod, dimethyl fumarate (DMF), or alemtuzumab have reduced numbers of CD4+ and CD8+ T cells, as well as Treg subsets, with fingolimod causing the most pronounced decrease in T cell subsets. In contrast, teriflunomide and interferon (IFN) β have minimal impact on T cells, and natalizumab marginally increases the number of memory T cells in the blood. The effect of DMTs on the B cell, NKT and NK cell subsets is highly variable with alemtuzumab inducing a strong increase in the number of the most immature NK cells and its subsets.This study comprehensively evaluates the magnitude of the effect of different DMTs on blood immune cells providing a better understanding of therapy outcome. Furthermore, the lack of a discernible pattern in the effects of DMTs on blood immune cells suggests that multiple immune cells can independently modulate the disease.

Sofosbuvir (+) daclatasvir (+) ribavirin in Egyptian patients with hepatitis C virus: Therapeutic outcomes and the prognostic role of natural killer cells

BackgroundOne of the prominent causes of chronic liver disease worldwide is the hepatitis C virus (HCV). HCV believed that innate immunity contributes to a sustained virological response (SVR) to the treatment of Sofosbuvir (SOF) (+) Daclatasvir (DCV) (+) Ribavirin (RBV). This study aimed to evaluate the impact of SOF (+) DCV (+) RBV therapy and persistent HCV infection on the subset of natural killer cells (NK) in HCV genotype four patients from Egypt. Materials and MethodsOne hundred and ten patients with persistent HCV infections requiring SOF (+) DCV (+) RBV therapy were grouped, and a flow cytometry (FCM) study of the NK cell subset in peripheral blood was performed. The assessment was performed before and after three and/or six months of the cessation of viral suppression therapy when a patient had a long-term viral response (SVR). One hundred and ten volunteers from the National Liver Institute’s (NLI) blood bank were selected as controls. ResultsPatients with chronic HCV infection before therapy had considerably lower CD16+ and CD3− CD56+ cells than controls. Their levels increase during SOF (+) DCV (+) RBV therapy. In patients with SVR during treatment, CD16+ and CD3– CD56+ cells increased significantly compared to those who did not get SVR. Furthermore, CD56+ cells were significantly higher in patients with persistent infection before treatment than controls but diminished with the response to treatment. Conclusion: NK cell activation following SOF (+) DCV (+) RBV therapy and polarization to cytotoxicity occurred early in HCV antiviral therapy and was elevated in the respondents. Our data illustrated that establishing an inhibitory cytotoxic NK profile is related to therapeutic outcomes.

Soluble MICA in endometriosis pathophysiology: Impairs NK cell degranulation and effector functions.

Endometriosis exhibits several immune dysfunctions, including deficient natural killer (NK) cell cytotoxicity. MICA (MHC class I chain-related molecule A) is induced by biological stress and soluble MICA (sMICA) negatively modulates the expression of the activating receptor, NKG2D, reducing NK cells activities. We investigated the involvement of soluble MICA in NK cell-deficient activity in endometriosis. sMICA levels (serum and peritoneal fluid-PF) were evaluated by ELISA. Circulating NK cell subsets quantification and its NKG2D receptor expression, NK cell cytotoxicity and CD107a, IFN-γ and IL-10 expressions by NK cells stimulated with K562 cells were determined by flow cytometry. We found higher sMICA levels (serum and PF) in endometriosis, especially in advanced and deep endometriosis. Endometriosis presented lower percentages of CD56dim CD16+ cytotoxic cells and impaired NK cell responses upon stimulation, resulting in lower CD107a and IFN-γ expressions, and deficient NK cell cytotoxicity. NK cell stimulation in the MICA-blocked condition (mimicking the effect of sMICA) showed decreased cytotoxicity in initial endometriosis stages and the emergence of a negative correlation between CD107a expression and sMICA levels. We suggest that soluble MICA is a potential player in endometriosis pathophysiology with involvement in disease progression and severity, contributing to NK cell impaired IFN-γ response and degranulation. NK cell compartment exhibits multiple perturbations, including quantitative deficiency and impaired cytotoxicity, contributing to inadequate elimination of ectopic endometrial tissue.

Immunometabolic features of natural killer cells are associated with infection outcomes in critical illness.

Immunosuppression increases the risk of nosocomial infection in patients with chronic critical illness. This exploratory study aimed to determine the immunometabolic signature associated with nosocomial infection during chronic critical illness. We prospectively recruited patients who were admitted to the respiratory care center and who had received mechanical ventilator support for more than 10 days in the intensive care unit. The study subjects were followed for the occurrence of nosocomial infection until 6 weeks after admission, hospital discharge, or death. The cytokine levels in the plasma samples were measured. Single-cell immunometabolic regulome profiling by mass cytometry, which analyzed 16 metabolic regulators in 21 immune subsets, was performed to identify immunometabolic features associated with the risk of nosocomial infection. During the study period, 37 patients were enrolled, and 16 patients (43.2%) developed nosocomial infection. Unsupervised immunologic clustering using multidimensional scaling and logistic regression analyses revealed that expression of nuclear respiratory factor 1 (NRF1) and carnitine palmitoyltransferase 1a (CPT1a), key regulators of mitochondrial biogenesis and fatty acid transport, respectively, in natural killer (NK) cells was significantly associated with nosocomial infection. Downregulated NRF1 and upregulated CPT1a were found in all subsets of NK cells from patients who developed a nosocomial infection. The risk of nosocomial infection is significantly correlated with the predictive score developed by selecting NK cell-specific features using an elastic net algorithm. Findings were further examined in an independent cohort of COVID-19-infected patients, and the results confirm that COVID-19-related mortality is significantly associated with mitochondria biogenesis and fatty acid oxidation pathways in NK cells. In conclusion, this study uncovers that NK cell-specific immunometabolic features are significantly associated with the occurrence and fatal outcomes of infection in critically ill population, and provides mechanistic insights into NK cell-specific immunity against microbial invasion in critical illness.

Distinctive CD56dim NK subset profiles and increased NKG2D expression in blood NK cells of Parkinson’s disease patients

Mounting data suggest an important role for the immune system in Parkinson’s disease (PD). Previous evidence of increased natural killer (NK) cell populations in PD suggests a potential role of NK cells in the pathogenesis of the disease. Previous studies have analyzed NK cell populations using aggregation by variable expression of CD56 and CD16. It remains unknown what differences may exist between NK cell subpopulations when stratified using more nuanced classification. Here, we profile NK cell subpopulations and elucidate the expressions of activating, NKG2D, inhibitory, NKG2A, and homing, CX3CR1, receptors on NK cell subpopulations in PD and healthy controls (HC). We analyzed cryopreserved PMBC samples using a 10-color flow cytometry panel to evaluate NK cell subpopulations in 31 individuals with sporadic PD and 27 HC participants. Here we identified significant differences in the CD56dim NK subset that changes with disease severity in PD. Furthermore, the expressions of NKG2D in all three NK cell subsets were significantly elevated in PD patients compared to HC. Notably, NKG2A expression in the CD56bright NK subset increased in PD patients with longer disease duration but there were no changes in CX3CR1. In summary, our data suggests that changes in NK cells may be influenced by the clinical severity and duration of PD.

The Macrophage Landscape Across the Lifespan of a Human Cardiac Allograft.

Much of our knowledge of organ rejection after transplantation is derived from rodent models. We used single-nucleus RNA sequencing to investigate the inflammatory myocardial microenvironment in human pediatric cardiac allografts at different stages after transplantation. We distinguished donor- from recipient-derived cells using naturally occurring genetic variants embedded in single-nucleus RNA sequencing data. Donor-derived tissue resident macrophages, which accompany the allograft into the recipient, are lost over time after transplantation. In contrast, monocyte-derived macrophages from the recipient populate the heart within days after transplantation and form 2 macrophage populations: recipient MP1 and recipient MP2. Recipient MP2s have cell signatures similar to donor-derived resident macrophages; however, they lack signatures of pro-reparative phagocytic activity typical of donor-derived resident macrophages and instead express profibrotic genes. In contrast, recipient MP1s express genes consistent with hallmarks of cellular rejection. Our data suggest that recipient MP1s activate a subset of natural killer cells, turning them into a cytotoxic cell population through feed-forward signaling between recipient MP1s and natural killer cells. Our findings reveal an imbalance of donor-derived and recipient-derived macrophages in the pediatric cardiac allograft that contributes to allograft failure.

Integrated Analysis of Single-Cell and Bulk RNA Sequencing Data Reveals Memory-like NK Cell Subset Associated with Mycobacterium tuberculosis Latency.

Natural killer (NK) cells are innate-like lymphocytes that belong to the family of type-1 innate lymphoid cells and rapidly respond to virus-infected and tumor cells. In this study, we have combined scRNA-seq data and bulk RNA-seq data to define the phenotypic and molecular characteristics of peripheral blood NK cells. While the role of NK cells in immune surveillance against virus infections and tumors has been well established, their contribution to protective responses to other intracellular microorganisms, such as Mycobacterium tuberculosis (Mtb), is still poorly understood. In this study, we have combined scRNA-seq data and bulk RNA-seq data to illuminate the molecular characteristics of circulating NK cells in patients with active tuberculosis (TB) disease and subjects with latent Mtb infection (LTBI) and compared these characteristics with those of healthy donors (HDs) and patients with non-TB other pulmonary infectious diseases (ODs). We show here that the NK cell cluster was significantly increased in LTBI subjects, as compared to patients with active TB or other non-TB pulmonary diseases and HD, and this was mostly attributable to the expansion of an NK cell population expressing KLRC2, CD52, CCL5 and HLA-DRB1, which most likely corresponds to memory-like NK2.1 cells. These data were validated by flow cytometry analysis in a small cohort of samples, showing that LTBI subjects have a significant expansion of NK cells characterized by the prevalence of memory-like CD52+ NKG2C+ NK cells. Altogether, our results provide some new information on the role of NK cells in protective immune responses to Mtb.

Aberrant NK cell profile in gestational diabetes mellitus with fetal growth restriction.

Gestational diabetes mellitus (GDM) is a gestational disorder characterized by hyperglycemia, that can lead to dysfunction of diverse cells in the body, especially the immune cells. It has been reported that immune cells, specifically natural killer (NK) cells, play a crucial role in normal pregnancy. However, it remains unknown how hyperglycemia affects NK cell dysfunction thus participates in the development of GDM. In this experiment, GDM mice were induced by an intraperitoneal injection of streptozotocin (STZ) after pregnancy and it has been found that the intrauterine growth restriction occurred in mice with STZ-induced GDM, accompanied by the changed proportion and function of NK cells. The percentage of cytotoxic CD27-CD11b+ NK cells was significantly increased, while the proportion of nourished CD27-CD11b- NK cells was significantly reduced in the decidua of GDM mice. Likewise, the same trend appeared in the peripheral blood NK cell subsets of GDM patients. What's more, after intrauterine reinfusion of NK cells to GDM mice, the fetal growth restriction was alleviated and the proportion of NK cells was restored. Our findings provide a theoretical and experimental basis for further exploring the pathogenesis of GDM.

The effects of aging, sex, and tumor burden on the peripheral blood immune cell profile and absolute counts.

Background: To better assess the peripheral immune status and aid in the early diagnosis and prognosis of tumors, we compared the proportion and absolute counting of peripheral immune cell subsets in healthy individuals and tumor patients of varying ages, taking into account the impact of sex and tumor metastasis. Methods: We used peripheral blood mononuclear cell (PBMC) samples from 520 patients with various tumor types and 109 healthy volunteers. The absolute numbers of lymphocytes and monocytes were identified by an automated blood analyzer, and multi-parameter flow cytometry was used to examine the subsets of natural killer (NK) cells (CD3-CD16+CD56+), T cells (CD3+CD4+/CD8+), and mononuclear cells (CD14+) in PBMC. Results: The percentage of T cells (CD3+) in peripheral blood mononuclear cells (PBMC) was 55.83% VS 45.54% (P<0.0001) between healthy volunteers and tumor patients, showing a significant downward trend. Meanwhile, the percentages of monocytes (CD14+) and NK cells (CD3-CD16+CD56+) showed a significant upward trend. Single factor or multifactor analysis yielded identical findings on the proportion of PBMC between healthy individuals and patients with different malignancies, considering the three confounding variables of age, sex, and tumor metastasis. Conclusion: The proportion and absolute counting of acquired immune T cells, innate immune NK cells, and monocytes in PBMCs all exhibit substantial changes between cancer patients and healthy individuals, and the differences are influenced by age, sex, and tumor progression.