A high-throughput assay of NK cell activity in whole blood and its clinical application

Use of a platform with lens-free shadow imaging technology to monitor natural killer cell activity

Natural killer (NK) cells are a crucial component of the innate immune system. This study introduces Cellytics NK, a novel platform for rapid and precise measurement of NK cell activity. This platform combines an NK-specific activation stimulator cocktail (ASC) and lens-free shadow imaging technology (LSIT), using optoelectronic components. LSIT captures digital hologram images of resting and ASC-activated NK cells, while an algorithm evaluates cell size and cytoplasmic complexity using shadow parameters. The combined shadow parameter derived from the peak-to-peak distance and width standard deviation rapidly distinguishes active NK cells from inactive NK cells at the single-cell level within 30 s. Here, the feasibility of the system was demonstrated by assessing NK cells from healthy donors and immunocompromised cancer patients, demonstrating a significant difference in the innate immunity index (I3). Cancer patients showed a lower I3 value (161%) than healthy donors (326%). I3 was strongly correlated with NK cell activity measured using various markers such as interferon-gamma, tumor necrosis factor-alpha, perforin, granzyme B, and CD107a. This technology holds promise for advancing immune functional assays, offering rapid and accurate on-site analysis of NK cells, a crucial innate immune cell, with its compact and cost-effective optoelectronic setup, especially in the post-COVID-19 era.

Interferon-Gamma Secretion Is Significantly Decreased in Stage III Breast Cancer Patients

Even though some studies have shown possible clinical relationship between molecular subtypes and tumor infiltrating natural killer (NK) cells around tumors, there are few studies showing the clinical relevance of peripheral NK cell activity at diagnosis in female patients with invasive breast cancer. A total of 396 female invasive breast cancer patients who received curative surgical treatment from March 2017 to July 2021 were retrospectively analyzed. NK cell activation-induced interferon-gamma (IFN-γ) secretion measured by enzyme-linked immunosorbent assay was used to measure the activity of peripheral NK cells. Statistical analyses were performed to determine clinical relationships with major clinicopathologic parameters. Quadripartite NK cell activity measured by induced interferon-gamma showed significant relevance with staging and body mass index, and some of the inflammatory serological markers, namely N/L (neutrophil/lymphocyte), P/N (platelet/neutrophil), and P/L (platelet/lymphocyte), showed significantly different NK activity in each interval by univariate analysis. A binary subgroup analysis, setting the IFN-γ secretion cut-off at 100 pg/mL, showed that stage III was significantly increased and axillary lymph node metastasis positivity was increased in the group of IFN-γ < 100 pg/mL, and IFN-γ secretion decreased with an increasing N stage, increased BMI (body mass index), and decreased production of IFN-γ. Following this, the same binary analysis, but with the IFN-γ secretion cut-off at 250 pg/mL, also showed that secretion in stage III was increased in those concentrations with <250 pg/mL, axillary lymph node positivity appeared to be correlated, and BMI ≥ 30 increased in prevalence. Additional ANOVA post hoc tests (Bonferroni) were performed on some serological markers that tended to be somewhat inconsistent. By subgroup analysis with Bonferroni adjustment between the IFN-γ secretion and TNM stage, no significant difference in IFN-γ secretion could be identified at stages I, II, and IV, but at stage III, the IFN-γ secretion < 100 pg/mL was significantly higher than 250 ≤ IFN-γ secretion < 500 pg/mL or IFN-γ secretion ≥ 500 pg/mL. According to this study, stage III was significantly associated with the lowest IFN-γ secretion. Compared to a higher level of IFN-γ secretion, a lower level of IFN-γ secretion seemed to be associated with increased body mass index. Unlike when IFN-γ secretion was analyzed in quartiles, as the IFN-γ secretion fell below 100 pg/mL, the correlation between axillary lymph node positivity and increased N stage, increased BMI, and increased N/L and P/L, which are suggested poor prognostic factors, became more pronounced. We think a peripheral IFN-γ secretion test might be convenient and useful tool for pretreatment risk assessment and selecting probable candidates for further treatment such as immunotherapy in some curable but high-risk invasive breast cancer patients, compared to other costly assaying of tissue NK cell activity at diagnosis.

Integrative Magneto-Microfluidic Separation of Immune Cells Facilitates Clinical Functional Assays

Accurately analyzing the functional activities of natural killer (NK) cells in clinical diagnosis remains challenging due to their coupling with other immune effectors. To address this, an integrated immune cell separator is required, which necessitates a streamlined sample preparation workflow including immunological cell isolation, removal of excess red blood cells (RBCs), and buffer exchange for downstream analysis. Here, a self-powered integrated magneto-microfluidic cell separation (SMS) chip is presented, which outputs high-purity target immune cells by simply inputting whole blood. The SMS chip intensifies the magnetic field gradient using an iron sphere-filled inlet reservoir for high-performance immuno-magnetic cell selection and separates target cells size-selectively using a microfluidic lattice for RBC removal and buffer exchange. In addition, the chip incorporates self-powered microfluidic pumping through a degassed polydimethylsiloxane chip, enabling the rapid isolation of NK cells at the place of blood collection within 40 min. This chip is used to isolate NK cells from whole blood samples of hepatocellular cancer patients and healthy volunteers and examined their functional activities to identify potential abnormalities in NK cell function. The SMS chip is simple to use, rapid to sort, and requires small blood volumes, thus facilitating the use of immune cell subtypes for cell-based diagnosis.

Low Muscle and High Fat Percentages Are Associated with Low Natural Killer Cell Activity: A Cross-Sectional Study

This study aimed to investigate whether body fat and muscle percentages are associated with natural killer cell activity (NKA). This was a cross-sectional study, conducted on 8058 subjects in a medical center in Korea. The association between the muscle and fat percentage tertiles and a low NKA, defined as an interferon-gamma level lower than 500 pg/mL, was assessed. In both men and women, the muscle mass and muscle percentage were significantly low in participants with a low NKA, whereas the fat percentage, white blood cell count, and C-reactive protein (CRP) level were significantly high in those with a low NKA. Compared with the lowest muscle percentage tertile as a reference, the fully adjusted odd ratios (ORs) (95% confidence intervals (CIs)) for a low NKA were significantly lower in T2 (OR: 0.69; 95% CI: 0.55-0.86) and T3 (OR: 0.74; 95% CI: 0.57-0.95) of men, and T3 (OR: 0.76; 95% CI: 0.59-0.99) of women. Compared with the lowest fat percentage tertile as a reference, the fully adjusted OR was significantly higher in T3 of men (OR: 1.31; 95% CI: 1.01-1.69). A high muscle percentage was significantly inversely associated with a low NKA in men and women, whereas a high fat percentage was significantly associated with a low NKA in men.

Relationship between Serum Cortisol, Dehydroepiandrosterone Sulfate (DHEAS) Levels, and Natural Killer Cell Activity: A Cross-Sectional Study

The adrenal steroid hormones, cortisol and dehydroepiandrosterone sulfate (DHEAS), are associated with the immune system in opposite actions. This study aimed to investigate the relationship between cortisol and DHEAS serum concentrations, their ratio (CDR), and natural killer cell activity (NKA). This cross-sectional study included 2275 subjects without current infection or inflammation in the final analyses. NKA was estimated by measuring the amount of interferon-gamma (IFN-γ) released by activated natural killer cells; low NKA was defined as IFN-γ level < 500 pg/mL. Cortisol, DHEAS levels, and CDRs were categorized by quartiles in men, premenopausal women, and postmenopausal women. Compared with the lowest quartile as reference, the adjusted odd ratios (ORs) and 95% confidence intervals (CIs) for low NKA of the highest cortisol and CDR group were 1.66 (1.09-2.51) and 1.68 (1.11-2.55) in men, 1.58 (1.07-2.33) and 2.33 (1.58-3.46) in premenopausal women, and 2.23 (1.28-3.87) and 1.85 (1.07-3.21) in postmenopausal women. Only in premenopausal women, the highest DHEAS group showed significantly lower risk of low NKA (OR: 0.51, 95% CI: 0.35-0.76). HPA axis activation indicated as high cortisol level, CDR was significantly associated with low NKA, while high DHEAS levels were inversely associated with low NKA in premenopausal women.

NK cell activity and methylated HOXA9 ctDNA as prognostic biomarkers in patients with non-small cell lung cancer treated with PD-1/PD-L1 inhibitors

BACKGROUND

PD-1/PD-L1 inhibitors have improved survival for patients with non-small cell lung cancer (NSCLC). We evaluated natural killer cell activity (NKA) and methylated HOXA9 circulating tumor DNA (ctDNA) as prognostic biomarkers in NSCLC patients treated with PD-1/PD-L1 inhibitors.

METHODS

Plasma was prospectively collected from 71 NSCLC patients before treatment with PD-1/PD-L1 inhibitors and before cycles 2-4. We used the NK Vue^® assay to measure the level of interferon gamma (IFNγ) as a surrogate for NKA. Methylated HOXA9 was measured by droplet digital PCR.

RESULTS

A score combining NKA and ctDNA status measured after one treatment cycle had a strong prognostic impact. Group 1 had IFNγ < 250 pg/ml and detectable ctDNA (n = 27), group 2 consisted of patients with either low levels of IFNγ and undetectable ctDNA or high levels of IFNγ and detectable ctDNA (n = 29), group 3 had IFNγ ≥250 pg/ml and undetectable ctDNA (n = 15). Median OS was 221 days (95% CI 121-539 days), 419 days (95% CI 235-650 days), and 1158 days (95% CI 250 days-not reached), respectively (P = 0.002). Group 1 had a poor prognosis with a hazard ratio of 5.560 (95% CI 2.359-13.101, n = 71, P < 0.001) adjusting for PD-L1 status, histology, and performance status.

CONCLUSIONS

Combining NKA and ctDNA status after one cycle of treatment was prognostic in patients with NSCLC treated with PD-1/PD-L1 inhibitors.

Effect of surgical pleth index-guided remifentanil administration on perioperative outcomes in elderly patients: a prospective randomized controlled trial

BACKGROUND

During general anesthesia, the surgical pleth index (SPI) monitors nociception. The evidence of SPI in the elderly remains scarce. We aimed to investigate whether there is a difference in perioperative outcomes following intraoperative opioid administration according to the surgical pleth index (SPI) value versus hemodynamic parameters (heart rate or blood pressure) in elderly patients.

METHODS

Patients aged 65-90 years who underwent laparoscopic colorectal cancer surgery under sevoflurane/remifentanil anesthesia were randomized to receive remifentanil guided by SPI (SPI group) or conventional clinical judgment based on hemodynamic parameters (conventional group). The primary endpoint was intraoperative remifentanil consumption. Secondary endpoints were intraoperative hemodynamic instability, pain score, fentanyl consumption and delirium in the post-anesthesia care unit (PACU), and perioperative changes in interleukin-6 and natural killer (NK) cell activity.

RESULTS

Seventy-five patients (38, SPI; 37, conventional) were included in the study. The SPI group consumed significantly more remifentanil intraoperatively than the conventional group (mean ± SD, 0.13 ± 0.05 vs. 0.06 ± 0.04 μg/kg/min, P < 0.001). Intraoperative hypertension and tachycardia were more common in the conventional group than in the SPI group. Pain score in the PACU (P = 0.013) and the incidence of delirium in the PACU were significantly lower in the SPI group than the conventional group (5.2% vs. 24.3%, P = 0.02). There was no significant difference in NK cell activity and interleukin-6 level.

CONCLUSIONS

In the elderly patients, SPI-guided analgesia provided appropriate analgesia with sufficient intraoperative remifentanil consumption, lower incidence of hypertension/ tachycardia events, and a lower incidence of delirium in the PACU than the conventional analgesia. However, SPI-guided analgesia may not prevent perioperative immune system deterioration.

TRIAL REGISTRATION

The randomized controlled trial was retrospectively registered in the UMIN Clinical Trials Registry (trial number: UMIN000048351; date of registration: 12/07/2022).

Gross Total Resection Promotes Subsequent Recovery and Further Enhancement of Impaired Natural Killer Cell Activity in Glioblastoma Patients

Highlights

Natural killer cell activity is dramatically impaired in patients with glioblastoma.

Surgical resection of glioblastoma promotes redistribution of NK cell subsets and increases NK cell activity 30 days after surgery.

Gross total resection rather than subtotal resection significantly recovers and further increases the impaired NK cell activity in patients with glioblastoma.

Abstract

Glioblastoma is the most common primary malignant brain tumor, and median survival is relatively short despite aggressive standard treatment. Natural killer (NK) cell dysfunction is strongly associated with tumor recurrence and metastasis but is unclear in glioblastoma. NK activity (NKA) represents NK cell-secreted interferon-γ (IFN-γ), which modulates immunity and inhibits cancer progression. This study aimed to analyze NKA in glioblastoma patients to obtain a clearer overview of immunity surveillance. From 2020 to 2021, a total of 20 patients and six healthy controls were recruited. Peripheral blood samples were collected preoperatively and on postoperative days (POD) 3 and 30. Then, NKA was measured using the NK VUE kit. Although NKA decreased on POD3, it recovered and further significantly enhanced on POD30, with a nearly five-fold increase compared to baseline (p = 0.004). Furthermore, the percentage of CD56^brightCD16⁻ NK cells decreased significantly on POD3 (p = 0.022) and further recovered on PO30. Subgroup analysis of extent surgical resection further revealed that the recovery of impaired NKA was attributable to gross total resection (GTR) rather than subtotal resection (STR). In conclusion, NKA is significantly impaired in glioblastoma, and GTR has demonstrated superior benefit in improving the suppressed NKA and increased CD56^brightCD16⁻ NK subset in glioblastoma patients, which may be associated with subsequent patients’ prognosis. Therefore, the goal of performing GTR for glioblastoma should be achieved when possible since it appears to increase NKA cell immunity.

A Case-Control Study on the Changes in Natural Killer Cell Activity following Administration of Polyvalent Mechanical Bacterial Lysate in Korean Adults with Recurrent Respiratory Tract Infection

Polyvalent mechanical bacterial lysate (PMBL) is used for the treatment and prevention of recurrent respiratory tract infections. Although PMBL is an immunostimulant, it remains unknown whether treatment with PMBL influences natural killer cell activity (NKA). Hence, this case-control study compared the changes in IFN-γ levels (surrogate index for NKA) following PMBL treatment or time passing between the PMBL-treated group and controls. The treatment group included adults who had a PMBL prescription for three months against recurrent respiratory tract infection from an outpatient clinic, while the control group had healthy adults visiting the health promotion center for periodic health check-ups. The control group (N = 506) showed no change in IFN-γ levels, while the treatment group (N = 301) showed a significant increase in mean from 462.8 to 749.3 pg/mL after PMBL treatment. In the subgroup with IFN-γ <500 pg/mL, IFN-γ levels significantly increased in both groups. However, the change in the treatment group (287 ± 822 pg/mL) was greater than that in the control group (58 ± 809 pg/mL), and the interaction between the visit and case/control was significant (p = 0.030) in a generalized estimating equation model. In conclusion, NKA increased in the subjects with recurrent respiratory tract infections with PMBL treatment.

Impact of High-Intensity Circuit Resistance Exercise on Physical Fitness, Inflammation, and Immune Cells in Female Breast Cancer Survivors: A Randomized Control Trial

Questions remain about whether resistance exercise has a positive effect on immune and inflammatory cells. The purpose of this study was to evaluate the effect of 12 weeks of high-intensity circuit resistance exercise (HCRE) on inflammation and immune cells, and physical fitness, of female breast cancer survivors (FBCSs). Thirty FBCSs were randomly assigned to the HCRE (n = 15) and control (n = 15) groups. HRCE was administered for 50 min a day, 2–3 times a week, for 12 weeks. The control group only performed activities of daily living during the study period. Baseline and post-intervention measures included body composition, muscular strength, muscular endurance, flexibility, reaction time, balance, inflammation, and immune cell measurements. The results showed that HCRE improved body mass index, body fat, muscle mass, grip strength, back muscle strength, sit-up, whole-body reaction, standing on one leg with eyes closed, Y-balance test, and NKCA in FBCSs. The improvement of physical strength and immune cells of FBCSs was achieved using the 12-week HRCE program. Future studies must analyze various exercise intensities and types, and should be conducted on other cancer survivors. In addition, strategies should be developed to allow FBCSs to participate in resistance training.

Clinical Effects of Using A Massage Chair on Stress Measures In Adults: A Pilot Randomized Controlled Trial

OBJECTIVE

Since the clinical benefits of a massage chair have not been fully elucidated, we aimed to assess the effects of the long-term use of a massage chair on stress measures in older adults.

DESIGN

Randomized controlled trial SETTING: Community. Interventions In total, 80 adults aged 50-75 years were randomly assigned to the intervention group (n=41) and control group (n=39). The intervention group used the massage chair twice a day for 6 months. The control group was educated about lifestyle modification.

MAIN OUTCOME MEASURES

The primary outcome was the change in serum cortisol levels in the morning (8 a.m.) and afternoon (1 p.m.), and the secondary outcomes included changes in levels of dehydroepiandrosterone-sulfate (DHEA-S), serotonin, insulin-like growth factor, erythrocyte sedimentation rate, high sensitivity C-reactive protein, and natural killer cell activity, and results from a questionnaire on mood, cognition, and quality of life.

RESULTS

The use of the massage chair was associated with a decreasing trend in serum cortisol levels at 1 p.m. (-2.68 ug/dL, p = 0.059). Serum DHEA-S levels significantly decreased with the intervention (-9.66 ug/dL, p = 0.003). In addition, the perceived rate of depression and health status considerably improved following the intervention.

CONCLUSIONS

Chronic stress in adults could be effectively managed using a massage chair.

Cross-Sectional and Time-Dependent Analyses on Inflammatory Markers Following Natural Killer Cell Activity

The function of natural killer (NK) cells in inflammation has not been explored enough in large-scale population studies. The cross-sectional and time-dependent relationship between NK cell activity (NKA) and inflammatory markers was examined. Methods: A total of 7031 subjects were involved in the cross-sectional analyses. Non-linear relationship between NKA and inflammatory indices was analyzed using generalized additive models. The time-dependent changes were analyzed in 1005 subjects with repeated measurement in 3–6 months. The changes in inflammatory markers were analyzed based on the changes in NKA. Results: As NKA reduces to a very low level, the white blood cell (WBC) and neutrophil counts increase sharply, and the lymphocyte count exhibits a slow decline. With increasing NKA larger than about 500 pg/mL, WBC and neutrophil-lymphocyte ratio (NLR) reduces in a mild slope. Among the subjects with repeated measurements, the follow-up NKA was increased with advancing baseline NKA levels. The subjects with a reduction in NKA indicated increment in WBC count, neutrophil count, and NLR, and decrease in lymphocyte count. Conclusions: Very low levels of NKA suggest a high inflammatory immune response. The changes in NKA may interact with the balance between neutrophils and lymphocytes.

Bispecific Antibody Designed for Targeted NK Cell Activation and Functional Assessment for Biomedical Applications

Natural killer (NK) cells serve as key innate effectors and their activity has been considered a prognostic biomarker in diverse human diseases. Currently, NK cell functional assays have several problems primarily related to adequate preparation, labeling, or treatment of target cells, which are cumbersome and often hamper consistent sensitivity for NK cells. Here, bispecific antibodies (BsAb's) targeting NKG2D and 2B4 receptors, whose combination mounts selective cytotoxicity and IFN-γ production of NK cells, are developed as acellular, consistent, and easy-to-use strategies for assessing NK cell functions. These NK cell activator BsAb's (NKABs) are constructed in symmetric dual bivalent formats with different interdomain spacings [immunoglobulin G (IgG)-single-chain variable fragment (scFv) and dual-variable domain (DVD)-Ig] and kappa constant (Cκ)-scFv format linking two scFv's with a Cκ domain. These NKABs are specific and superior to a combination of monospecific antibodies for NK cell activation. NKAB elicits both direct cytotoxicity and IFN-γ production via integration of NKG2D and 2B4 signals. Moreover, stimulation with NKAB IgG-scFv and Cκ-scFv reveals defective NK cell functions in X-linked lymphoproliferative disease involving 2B4 dysfunction in NK cells and multiple myeloma in peripheral blood mononuclear cells and whole blood, respectively. Hence, this work provides a proof of concept that NKAB facilitates the reliable and comprehensive measurement of NK cell function in clinical settings for diagnostic and prognostic purposes.

Effect of Conventional Chemotherapies on Natural Killer Cell Activity

Background:

The effects of chemotherapeutics agents are considered to influence the immune system and cells due to their myelosuppressive and immunosuppressive functions. Natural killer cells are one of the important components of the innate immune system and have a critical role against tumor cells and infections.

Objective:

The study was aimed to demonstrate whether conventional chemotherapies had an effect on Natural Killer (NK) cell activity.

Methods:

Forty-nine adjuvant and 19 first-time metastatic chemotherapy-naïve cancer patients were recruited into the study. Blood samples at pre-chemotherapy and post-chemotherapy, at 1st and 4th cycles, were obtained for NK cell activity.

Results:

We found no difference between baseline and post-chemotherapy NK cell activity levels. In addition, we found no difference between pre-chemotherapy and post-chemotherapy NK cell activity in both adjuvant and metastatic cancer patients separately.

Conclusion:

Conventional chemotherapy seems to have no effect on NK cell activity levels in cancer patients in both metastatic and adjuvant settings.

Vitamin D and Exercise Are Major Determinants of Natural Killer Cell Activity, Which Is Age- and Gender-Specific

Background

The coronavirus-19 disease (COVID-19) pandemic reminds us of the importance of immune function, even in immunologically normal individuals. Multiple lifestyle factors are known to influence the immune function.

Objective

The aim was to investigate the association between NK cell activity (NKA) and multiple factors including vitamin D, physical exercise, age, and gender.

Methods

This was a cross-sectional association study using health check-up and NKA data of 2,095 subjects collected from 2016 to 2018 in a health check-up center in the Republic of Korea. NKA was measured using the interferon-γ (IFN-γ) stimulation method. The association of NKA with 25-(OH)-vitamin D (25(OH)D) and other factors was investigated by multiple logistic regression analysis.

Results

The average age of subjects was 48.8 ± 11.6 years (52.9% of subjects were female). Among 2,095 subjects, 1,427 had normal NKA (NKA ≥ 500 pg IFN-γ/mL), while 506 had low NKA (100 ≤ NKA < 500 pg/mL), and 162 subjects had very low NKA (NKA < 100 pg/mL). Compared to men with low 25(OH)D serum level (< 20 ng/mL), vitamin D replete men (30–39.9 ng/mL) had significantly lower risk of very low NKA (OR: 0.358; 95% CI: 0.138, 0.929; P = 0.035). In women, both low exercise (OR: 0.529; 95% CI: 0.299, 0.939; P = 0.030) and medium to high exercise (OR: 0.522; 95% CI: 0.277, 0.981; P = 0.043) decreased the risk compared to lack of physical exercise. Interestingly, in men and women older than 60 years, physical exercise significantly decreased the risk. Older-age was associated with increased risk of very low NKA in men, but not in women.

Conclusion

Physical exercise and vitamin D were associated with NKA in a gender- and age-dependent manner. Age was a major risk factor of very low NKA in men but not in women.

Interferon-γ: teammate or opponent in the tumour microenvironment?

Cancer immunotherapy offers substantive benefit to patients with various tumour types, in some cases leading to complete tumour clearance. However, many patients do not respond to immunotherapy, galvanizing the field to define the mechanisms of pre-existing and acquired resistance. Interferon-γ (IFNγ) is a cytokine that has both protumour and antitumour activities, suggesting that it may serve as a nexus for responsiveness to immunotherapy. Many cancer immunotherapies and chemotherapies induce IFNγ production by various cell types, including activated T cells and natural killer cells. Patients resistant to these therapies commonly have molecular aberrations in the IFNγ signalling pathway or express resistance molecules driven by IFNγ. Given that all nucleated cells can respond to IFNγ, the functional consequences of IFNγ production need to be carefully dissected on a cell-by-cell basis. Here, we review the cells that produce IFNγ and the different effects of IFNγ in the tumour microenvironment, highlighting the pleiotropic nature of this multifunctional and abundant cytokine.

Multifunctional Microparticles with Stimulation and Sensing Capabilities for Facile NK Cell Activity Assay

Natural killer (NK) cells are a subset of innate lymphoid cells playing an important role in immune surveillance and early defense against infection and cancer. They recognize and directly kill infected or transformed cells. At the same time, they produce various cytokines and chemokines to regulate other immune cells. NK cell activity can be a useful marker for health screenings because impaired NK cell functions may indicate a more susceptible environment for infection or tumor development. Currently, most NK cell activity assays are focused on measuring either cytokine secretion, in particular, interferon γ (IFN-γ), or cytotoxicity against target cells such as K562, thus only providing partial information on NK cell activity. In order to develop a comprehensive test for measuring NK cell function, cytotoxicity and cytokine secretion ability should be measured simultaneously. In addition, current NK cell assays are performed by stimulating NK cells with cocktails of cytokines, antibody-coated beads, or live target cells. In this study, we developed multifunctional microparticles for NK cell activity assay (MNAs) that allow simultaneous stimulation and sensing various NK cell activities, including cytokine secretion and cytotoxicity. The surfaces of MNAs are decorated with multiple functional biomolecules, including antibodies that stimulate NK cells by engaging NK cell activating receptors, antibodies that can capture cytokines secreted by NK cells, and a peptide sensor that reacts with granzyme B, a key molecule released by NK cells for cytotoxicity. The performances of MNAs are assessed using flow cytometry and live cell imaging. NK cell activity is measured by simply mixing MNAs with NK cells and performing flow cytometry, and the results are comparable to those measured by standard NK cell activity assays.

Peripheral natural killer cell activity is associated with poor clinical outcomes in pancreatic ductal adenocarcinoma

BACKGROUND AND AIM

We aimed to measure the natural killer (NK) cell activity and pro-inflammatory cytokine levels in the peripheral blood of pancreatic cancer patients and investigate the correlation of NK cell activity and cytokines with cancer status and clinical outcomes.

METHODS

We prospectively enrolled patients who were pathologically diagnosed with pancreatic ductal adenocarcinoma (PDAC) between 2016 and 2017 at a tertiary hospital in Seoul, South Korea. As a control group, healthy participants were enrolled by mobile application recruitment.

RESULTS

A total of 203 patients were enrolled for this study (PDAC, n = 102; healthy participants, n = 101). The peripheral blood NK cell activity of PDAC patients was significantly lower than that of healthy participants (median level, 95 pg/mL vs 2000 pg/mL, P < 0.001), and decreased NK cell activity was correlated to poor clinical outcome in terms of response to chemotherapy, tumor progression, and survival. The pro-inflammatory cytokine interleukin-6 had a strong negative correlation with NK cell activity.

CONCLUSIONS

In pancreatic cancer patients, NK cell activity decreased as cancer progressed, and decreased NK cell activity was associated with poor clinical outcomes.

Blood natural killer cells during treatment in recurrent ovarian cancer

OBJECTIVE

Recent research indicated favorable prognostic impact of intratumoral natural killer (NK) cells in ovarian carcinoma (OC). The role of NK cells during chemotherapy in OC is unknown. We investigated impact of NK cells in OC patients treated with palliative chemotherapy.

METHODS

Participants receiving palliative chemotherapy for recurrent OC (N = 72) had prospectively blood samples at baseline and before cycle 2. NK cell counts were quantified by flow cytometry. NK cell activity was measured by the NK Vue^® assay, estimating interferon-gamma production. Overall survival (OS) was the primary endpoint. Cutoffs were predefined, NK numbers (≥184 × 10⁶ cells/L vs. <184 × 10⁶ cells/L) and NK activity (<200 pg/mL vs. ≥200 pg/mL).

RESULTS

Median OS in patients with low vs. high NK cell count at baseline was 7.1 months vs. 15.6 months (p = .028), respectively, and before cycle 2 was 5.7 vs. 17.3 months, p < .001, respectively. The difference in restricted mean survival (ΔRMST) was 5.7 months (95% CI: 3.3-8.0) at cycle 2 vs. 2.5 months (95% CI: -0.6 to 5.6) at baseline, showing a significant difference with no overlap of confidence intervals. In multivariate analyses, low NK cell count remained significant with a hazard ratio (HR)=2.83, 95% CI: 1.53-5.22, p = .001 (baseline) and HR = 3.34, 95% CI: 1.67-6.71, p = .001 (before cycle 2). Patients with both low NK count and NK activity at baseline (N = 20) had median OS 6.5 months vs. 11.5 months in patients with either high activity, high count or both (p = .007). In parallel, patients with both low NK activity and count at cycle 2 (N = 18) had a median survival of 4.0 months vs. 15.4 months (p < .001).

CONCLUSIONS

A low blood NK cell count in recurrent metastatic ovarian cancer during chemotherapy is associated with unfavorable prognostic impact. Early increase in survival difference based on NK cell status suggests an association between NK cell count and treatment benefit.

Assessment of NK Cell Activity Based on NK Cell-Specific Receptor Synergy in Peripheral Blood Mononuclear Cells and Whole Blood

Natural killer (NK) cells are cytotoxic innate lymphocytes endowed with a unique ability to kill a broad spectrum of cancer and virus-infected cells. Given their key contribution to diverse diseases, the measurement of NK cell activity (NKA) has been used to estimate disease prognosis or the effect of therapeutic treatment. Currently, NKA assays are primarily based on cumbersome procedures related to careful labeling and handling of target cells and/or NK cells, and they require a rapid isolation of peripheral blood mononuclear cells (PBMCs) which often necessitates a large amount of blood. Here, we developed an ELISA-based whole blood (WB) NKA assay involving engineered target cells (P815-ULBP1+CD48) providing defined and synergistic stimulation for NK cells via NKG2D and 2B4. WB collected from healthy donors (HDs) and patients with multiple myeloma (MM) was stimulated with P815-ULBP1+CD48 cells combined with IL-2. Thereafter, it utilized the serum concentrations of granzyme B and IFN-γ originating in NK cells as independent and complementary indicators of NKA. This WB NKA assay demonstrated that MM patients exhibit a significantly lower NKA than HDs following stimulation with P815-ULBP1+CD48 cells and had a good correlation with the commonly used flow cytometry-based PBMC NKA assay. Moreover, the use of P815-ULBP1+CD48 cells in relation to assessing the levels of NKG2D and 2B4 receptors on NK cells facilitated the mechanistic study and led to the identification of TGF-β1 as a potential mediator of compromised NKA in MM. Thus, our proposed WB NKA assay facilitates the reliable measurement of NKA and holds promise for further development as both a clinical and research tool.

A Flow Cytometry-Based Whole Blood Natural Killer Cell Cytotoxicity Assay Using Overnight Cytokine Activation

Background: Measurement of natural killer (NK) cell function has important clinical utility in several diseases. Although the flow cytometry (FC)-based 4-h NK cytotoxicity assay using peripheral blood mononuclear cells (PBMCs) in the clinical laboratory has been used for this purpose, this assay requires large amounts of blood and a rapid PBMC isolation step. Here, we developed an FC-based overnight NK cytotoxicity assay using whole blood (WB), and applied it to patients with liver diseases.

Methods: Peripheral blood of healthy volunteers (n = 28) and patients with liver diseases, including hepatocellular carcinoma (n = 19) and liver cirrhosis (n = 7), was analyzed for complete blood count, absolute NK cell count, and NK cell activity (NKA). NKA was evaluated in three assay types: an FC-based overnight WB NK cytotoxicity assay using carboxyfluorescein diacetate succinimidyl ester-labeled K562 cells in the presence of various cytokine combinations [including interleukin (IL)-2, IL-18, and IL-21], an FC-based 4-h PBMC NK cytotoxicity assay, and an FC-based CD107a degranulation assay using WB and PBMCs.

Results: Optimal cytokine combinations for NK cell activation in WB were determined (IL-2/IL-18, IL-2/IL-21, and IL-2/IL-18/IL-21). A good correlation was observed between WB and PBMC NK cytotoxicity assays; absolute NK cell counts were better correlated with the WB NK cytotoxicity assay than with the PBMC NK cytotoxicity assay. This WB NK cytotoxicity assay showed that patients with liver diseases had significantly lower NK cytotoxicity than healthy volunteers, under stimulation with various cytokines (p < 0.001).

Conclusion: The proposed FC-based overnight WB NK cytotoxicity assay correlates well with the conventional 4-h PBMC NK cytotoxicity assay, demonstrating future potential as a supportive assay for clinical laboratory research and observational studies.

Effects of Queso Blanco cheese containing Bifidobacterium longum KACC 91563 on fecal microbiota, metabolite and serum cytokine in healthy beagle dogs

The study describes the effects of administration of Queso Blanco cheese containing Bifidobacterium longum on the fecal microbiota, metabolite and serum cytokine in healthy beagle dogs. Twelve healthy beagle dogs were randomly divided in three groups of four dogs each:a control group, not fed with any cheese, and groups fed with Queso Blanco cheese with B. longum KACC 91563 (QCB) or without B. longum (QC) for 8 weeks. Fecal microbiota was analyzed using a culture-based method and 16s rRNA gene sequencing. Serum cytokine levels, activation of natural killer cells, and proliferation of peripheral blood mononuclear cells were determined. SPME-GC-MS method was used to determine the concentrations of short chain fatty acids and indole in dog feces. Administration of QCB for 4 weeks significantly increased the Bifidobacterium. QCB supplementation for 8 weeks reduceds Enterobacteriaceae and Clostridium perfringens (p < 0.05). The abundance of Fusobacterium, Blautia and Collinesella in QCB group were reduced as compared with the control group. Serum TNF-α and IL-6 levels at 8 weeks significantly increased in QCB group as compared with QC group. There was no change in the concentrations of total short chain fatty acids by B. longum at 0 and 4 weeks. At week 8, the acetic acid, propionic acid and butyric acid of the QCB and QC groups were significantly decreased compared to the control group. In conclusion, our results demonstrate that administration of QCB had positive effects on fecal microbiota and immune response in beagle dogs. We suggest that Queso Blanco cheese containing B. longum KACC 91563 could be used as a functional food for companion animals.

Impact of Smoking on Human Natural Killer Cell Activity: A Large Cohort Study

Some studies have reported a decrease in the natural killer (NK) cell activity in smokers. However, large-scale data on the relationship between NK cell activity and smoking are unavailable. A cross-sectional study was performed on 12,249 asymptomatic examinees who underwent an NK cell activity test, between January 2016 and May 2017. The test quantitated the amount of interferon-γ secreted into the plasma by NK cells, using a patented stimulatory cytokine. The mean age of the study population was 39.1 years, and the proportions of “never”, “former”, and “current” smokers were 65.5%, 20.9%, and 13.6%, respectively. Current smokers (1,422 pg/mL) had a lower median level of NK cell activity than never smokers (1,504 pg/mL, P = 0.039) and former smokers (1,791 pg/mL, P < 0.001). Among current smokers, NK cell activity decreased with increase in the number of cigarettes smoked among current smokers (median, 1,537, 1,429, and 1,175 pg/mL at <10, 10-19, and ≥ 20 pack-years, respectively; P < 0.001). Additionally, it decreased linearly with increasing quartiles of cotinine levels (median, 1,707, 1,636, 1,348, and 1,292 pg/mL at cotinine levels < 292, 292-879, 880-1,509, and ≥ 1,510 ng/mL, respectively; r = –0.122, P < 0.001). NK cell activity was lower in current smokers. It also decreased with an increase in the number of cigarettes smoked, and it was negatively correlated with cotinine levels among current smokers. Our findings indicate a clear relationship between smoking and decreased NK cell activity.

Solid and liquid state characterization of tetrahydrocurcumin using XRPD, FT-IR, DSC, TGA, LC-MS, GC-MS, and NMR and its biological activities

Tetrahydrocurcumin (THC) is one of the major metabolites of curcumin (CUR), an ancient bioactive natural polyphenolic compound. This research article describes both the solid and liquid state characterization of THC using advanced spectroscopic and thermo-analytical techniques. Anti-inflammatory, anti-oxidant, and neuroprotective activities of THC were investigated using in vitro cell lines. Liquid chromatography-mass spectrometry analysis revealed that our sample comprised 95.15% THC, 0.51% tetrahydrodemethoxycurcumin (THDC), 3.40% hexahydrocurcumin, and 0.94% octahydrocurcumin. Gas chromatography-mass spectrometry analysis indicated the presence of 96.68% THC and 3.32% THDC. THC in solution existed as keto-enol tautomers in three different forms at different retention time, but the enol form was found to be dominant, which was also supported by nuclear magnetic resonance analysis. THC was thermally stable up to 335.55 °C. THC exhibited more suppression of cytokines (TNF-α, IL-1β, and MIP-1α) than CUR in a concentration-dependent manner in mouse splenocytes, while NK-cell and phagocytosis activity was increased in macrophages. THC showed a significant reduction of free radicals (LPO) along with improved antioxidant enzymes (SOD and catalase) and increased free radical scavenging activity against ABTS⁺ radicals in HepG2 cells. THC displayed higher protection capability than CUR from oxidative stress and neuronal damage by improving cell viability against H₂O₂ induced HepG2 cells and MPP⁺ induced SH-SY5Y cells, respectively, in a concentration-dependent manner. Thus, a variation of the biological activities of THC might rely on its keto-enol form and the presence of other THC analogs as impurities. The present study could be advantageous for further research on THC for better understanding its physicochemical properties and biological variation.

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Solid and liquid state characterization of THC using advanced analytical techniques.

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THC existed in 3 different forms viz. one keto form, two enol forms in solution.

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THC was found to be thermally more stable than curcumin.

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THC exhibited significant suppression of proinflammatory cytokines, increased NK cells and phagocytosis activities.

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THC showed higher total anti-oxidant activity and neuroprotective activity than curcumin.

Natural Killer Cell Function Tests by Flowcytometry-Based Cytotoxicity and IFN-γ Production for the Diagnosis of Adult Hemophagocytic Lymphohistiocytosis

Although natural killer (NK) cell function is a hallmark of hemophagocytic lymphohistiocytosis (HLH), there is no standard method or data on its diagnostic value in adults. Thus, we performed a single-center retrospective study of 119 adult patients with suspected HLH. NK cell function was determined using both flowcytometry-based NK-cytotoxicity test (NK-cytotoxicity) and NK cell activity test for interferon-gamma (NKA-IFNγ). NK cell phenotype and serum cytokine levels were also tested. Fifty (42.0%) HLH patients showed significantly reduced NK cell function compared to 69 non-HLH patients by both NK-cytotoxicity and NKA-IFNγ (p < 0.001 and p = 0.020, respectively). Agreement between NK-cytotoxicity and NKA-IFNγ was 88.0% in HLH patients and 58.0% in non-HLH patients. NK-cytotoxicity and NKA-IFNγ assays predicted HLH with sensitivities of 96.0% and 92.0%, respectively. The combination of NKA-IFNγ and ferritin (>10,000 µg/L) was helpful for ruling out HLH, with a specificity of 94.2%. Decreased NK-cytotoxicity was associated with increased soluble IL-2 receptor levels and decreased CD56dim NK cells. Decreased NKA-IFNγ was associated with decreased serum cytokine levels. We suggest that both NK-cytotoxicity and NKA-IFNγ could be used for diagnosis of HLH. Further studies are needed to validate the diagnostic and prognostic value of NK cell function tests.

Natural Killer Cell Therapy: A New Treatment Paradigm for Solid Tumors

In treatments of solid tumors, adoptive transfer of ex vivo expanded natural killer (NK) cells has dawned as a new paradigm. Compared with cytotoxic T lymphocytes, NK cells take a unique position targeting tumor cells that evade the host immune surveillance by down-regulating self-antigen presentation. Recent findings highlighted that NK cells can even target cancer stem cells. The efficacy of allogeneic NK cells has been widely investigated in the treatment of hematologic malignancies. In solid tumors, both autologous and allogeneic NK cells have demonstrated potential efficacy. In allogeneic NK cell therapy, the mismatch between the killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) can be harnessed to increase the antitumor activity. However, the allogeneic NK cells cause more adverse events and can be rejected by the host immune system after repeated injections. In this regard, the autologous NK cell therapy is safer. This article reviews the published results of clinical trials and discusses strategies to enhance the efficacy of the NK cell therapy. The difference in immunophenotype of the ex vivo expanded NK cells resulted from different culture methods may affect the final efficacy. Furthermore, currently available standard anticancer therapy, molecularly targeted agents, and checkpoint inhibitors may directly or indirectly enhance the efficacy of NK cell therapy. A recent study discovered that NK cell specific genetic defects are closely associated with the tumor immune microenvironment that determines clinical outcomes. This finding warrants future investigations to find the implication of NK cell specific genetic defects in cancer development and treatment, and NK cell deficiency syndrome should be revisited to enhance our understanding. Overall, it is clear that NK cell therapy is safe and promises a new paradigm for the treatment of solid tumors.

Psychological intervention and its immune effect in cancer patients: A meta-analysis

OBJECTIVE

To determine whether psychological intervention (PI) changes the levels of immune indicators in cancer patients.

METHODS

We conducted a systematic search published up to July 2018, followed by a manual search. Randomized controlled trials were included. Two reviewers independently screened and extracted data, which were analyzed using Review manager 5.3.

RESULTS

Twenty-nine studies were included including four kinds of PI. Only stress management didn't result in immune changes; only cognitive behavior therapy affect NK cell activity. PI did not change immune indicators on cancer patients who completed therapy. Compared to patients not receiving PI, those received PI had significantly higher NK cell count and activity in whole blood; and serum levels of IL-2, IL-4, IFN-γ, lgA, and lgG. However, the differences in the serum levels of IL-6, IL-10, TNF-α, and IgM were not significant (P > .05), and the changes recorded for the CD3, CD4, and CD8 cell count, and CD4/CD8 ratios were inconsistent.

CONCLUSIONS

Although there are considerable evidences of PI's immune effect, but its magnitude was moderate. Therefore, it may be premature to conclude whether PI affects immunity of cancer patients. Further research is warranted, with special focus on the PI types and treatment methods.

Relationship between natural killer cell activity and glucose control in patients with type 2 diabetes and prediabetes

AIMS/INTRODUCTION

Natural killer (NK) cells are cytotoxic lymphocytes critical to human immunity. Previous studies showed correlations between NK cell function and blood glucose concentrations. The purpose of the present study was to assess the NK cell activity and various metabolic parameters in people with type 2 diabetes, prediabetes and normal glucose tolerance.

MATERIALS AND METHODS

A total of 49 participants were enrolled in the study. Anthropometric and biochemical parameters including age, sex, body mass index, smoking status, blood pressure, fasting plasma glucose, C-peptide, insulin, glycated hemoglobin, total cholesterol, triglyceride, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol were assessed. The 75 g oral glucose tolerance test was carried out for 2-h postload glucose level. Homeostatic model assessment was calculated for insulin resistance and β-cell function. NK cell activity was measured by detecting the circulating interferon-gamma level secreted from NK cells.

RESULTS

NK cell activity was lower in patients with type 2 diabetes (768.01 ± 650.35) compared with those with prediabetes (2,396.08 ± 653.76, P < 0.001) and normal glucose tolerance (2,435.31 ± 633.22, P < 0.001). In patients with type 2 diabetes, there was a significant inverse linear relationship between NK cell activity and fasting plasma glucose, glycated hemoglobin, and 2-h postload glucose level (all P < 0.001). Multiple regression analysis showed glycated hemoglobin to be an independent predictor of NK cell activity in patients with type 2 diabetes.

CONCLUSIONS

Compared with individuals with normal glucose tolerance or prediabetes, type 2 diabetes patients have a reduced NK cell activity, and it is significantly related to glucose control.

Correlation Between Natural Killer Cell Activity and Treatment Effect in Patients with Disseminated Cancer

INTRODUCTION

The aim of the present study was to analyze the possible correlation between Natural Killer (NK) cell activity as measured by the NK Vue assay and treatment efficacy in patients with disseminated cancer.

MATERIALS AND METHODS

The study included four trials encompassing palliative treatment, i.e. one trial on prostate- and ovarian cancer, respectively, and two trials on colorectal cancer. The current results are based on 93 patients with mature data on treatment effect. Blood samples were collected at baseline and prior to each treatment cycle into NK Vue. Following 24 hours of stimulation the level of interferon-gamma (IFNγ) in the plasma was measured as a surrogate for NK cell activity.

RESULTS

The relationship between NK cell activity and treatment response was similar across tumor types and treatment. The IFNγ either remained at or dropped to an abnormal level (<200 pg/mL) during treatment in group 1 (n = 35). In group 2 (n = 30) the level remained within a normal range (>200 pg/mL), while in group 3 (n = 28) it increased from an abnormal to a normal level. The response rate was 14%, 47%, and 82%, respectively, P < .001. The median progression free survival was 2.6 months (95% confidence interval (CI) 2.1-3.9), 10.0 months (95% CI 6.5-11.1), and 8.3 months (95% CI 6.5-8.7), respectively, P < .001 (log-rank).

CONCLUSION

Patients lacking the ability to mount an immune response during the first 2 months of treatment have a poor prognosis, and their clinical benefit of the treatment is questionable.

Clinical utility of a novel natural killer cell activity assay for diagnosing non-small cell lung cancer: a prospective pilot study

Purpose

Although decreased natural killer cell activity (NKA) has been observed in many solid cancers, clinical implication of NKA has been scarcely investigated in lung cancer. The objective of this study was to evaluate the potential of using NKA to support diagnosis of non-small cell lung cancer (NSCLC).

Materials and methods

We prospectively evaluated and compared peripheral blood NKA using a novel interferon-gamma releasing assay in healthy population (n=40), patients with benign lung disease (n=40), and those with NSCLC (n=71). We explored the correlation between NKA and clinical parameters and assessed diagnostic performance of NKA for NSCLC using receiver operating characteristic curve analysis.

Results

Median NKA values in healthy population, patients with benign lung disease, and those with NSCLC were 1,364.2, 1,438.2, and 406.3 pg/mL, respectively. NKA in NSCLC patients was significantly lower than that in the other two control groups (both P<0.001). At a cutoff value of NKA at 391.0 pg/mL, the area under the curve was 0.762 (95% CI: 0.685–0.838, P<0.001), with a sensitivity of 52.3%, a specificity of 91.0%, a positive predictive value of 85.3%, and a negative predictive value of 65.4% for the diagnosis of NSCLC. Multivariate analysis demonstrated that diagnosis of NSCLC is the only clinical parameter that was significantly associated with NKA (P<0.001).

Conclusion

This pilot study showed that patients with low NKA were more likely to have lung cancer. Further studies are warranted in order to establish the clinical utility of NKA test for diagnosing lung cancer.

GenESysV: a fast, intuitive and scalable genome exploration open source tool for variants generated from high-throughput sequencing projects

Background

High throughput sequencing technologies have been increasingly used in basic genetic research as well as in clinical applications. More and more variants underlying Mendelian and complex diseases are being discovered and documented using these technologies. However, identifying and obtaining a short list of candidate disease-causing variants remains challenging for most of the users after variant calling, especially for people without computational skills.

Results

We developed GenESysV (Genome Exploration System for Variants) as a scalable, intuitive and user-friendly open source tool. It can be used in any high throughput sequencing or genotyping project for storing, managing, prioritizing and efficient retrieval of variants of interest. GenESysV is designed for use by researchers from a wide range of disciplines and computational skills, including wet-lab scientists, clinicians, and bioinformaticians.

Conclusions

GenESysV is the first tool to be able to handle genomic variant dataset ranging in size from a few to thousands of samples and still maintain fast data importation and good query performance. It has a very intuitive graphical user interface and can also be used in studies where secured data access is an important concern. We believe this tool will benefit the human disease research community to speed up discoveries for genetic variants underlying human genetic disorders.

Electronic supplementary material

The online version of this article (10.1186/s12859-019-2636-5) contains supplementary material, which is available to authorized users.

Identification of Primary Natural Killer Cell Modulators by Chemical Library Screening with a Luciferase-Based Functional Assay

Natural killer (NK) cells are essential players of the innate immune response that secrete cytolytic factors and cytokines such as IFN-γ when contacting virus-infected or tumor cells. They represent prime targets in immunotherapy as defects in NK cell functions are hallmarks of many pathological conditions, such as cancer and chronic infections. The functional screening of chemical libraries or biologics would greatly help identify new modulators of NK cell activity, but commonly used methods such as flow cytometry are not easily scalable to high-throughput settings. Here we describe an efficient assay to measure the natural cytotoxicity of primary NK cells where the bioluminescent enzyme NanoLuc is constitutively expressed in the cytoplasm of target cells and is released in co-culture supernatants when lysis occurs. We fully characterized this assay using either purified NK cells or total peripheral blood mononuclear cells (PBMCs), including some patient samples, as effector cells. A pilot screen was also performed on a library of 782 metabolites, xenobiotics, and common drugs, which identified dextrometorphan and diphenhydramine as novel NK cell inhibitors. Finally, this assay was further improved by developing a dual-reporter cell line to simultaneously measure NK cell cytotoxicity and IFN-γ secretion in a single well, extending the potential of this system.

Association of neutrophil-to-lymphocyte ratio and natural killer cell activity revealed by measurement of interferon-gamma levels in a healthy population

BACKGROUND

While a method of assaying natural killer (NK) cell activity by measuring the amount of interferon (IFN)-γ released from NK cells has been proposed, no data are available about the factors that influence IFN-γ levels related to NK cell activity. NLR has recently been reported to be a predictor of several diseases. In the present study, we investigated the pre-analytical variables for NK cell activity using measurements of IFN-γ and the relationship between NLR and NK cell activity.

METHODS

The NK cell activity was assessed with the measurement of IFN-γ after stimulation with an NK cell-specific stimulant (NK Vue^™ , ATgen, Sungnam, Korea). One hundred and six adult volunteers were recruited and analysis of their complete blood count data and serum C-reactive protein was done. Blood sample from 59 of the participants was also used for analysis of lymphocyte subpopulations.

RESULT

Natural killer cell activity varied widely (range, 44.2-1775.6 pg/mL). NK cell activity was higher in females than in males (P = 0.014). NK cell activity decreased with increasing NLR (P = 0.004, r = -0.32) but NK cell activity showed no significant association with NK cell count or other lymphocyte subpopulations. NK cell activity levels according to CRP quartile were significantly different (P = 0.025).

CONCLUSION

We have observed that NK cell activity when assessed by IFN-γ level measurement was negatively correlating with NLR. This result can be helpful in interpreting or predicting NK cell activity in the clinical environment.

Physical Inactivity and Unhealthy Metabolic Status Are Associated with Decreased Natural Killer Cell Activity

PURPOSE

Several studies have reported relationships among physical activity, healthy metabolic status, and increased natural killer (NK) cell activity. However, large-scale data thereon are lacking. Thus, the present study aimed to assess NK cell activity according to physical activity and metabolic status.

MATERIALS AND METHODS

A cross-sectional study was performed on 12014 asymptomatic examinees. Using a patented stimulatory cytokine, NK cell activity was quantitated by the amount of interferon-γ secreted into the plasma by NK cells. Physical activity levels were assessed using the validated Korean version of the International Physical Activity Questionnaire Short Form.

RESULTS

The physically inactive group showed lower NK cell activity than the minimally active group (median, 1461 vs. 1592 pg/mL, p<0.001) and health-enhancing physically active group (median, 1461 vs. 1712 pg/mL, p=0.001). Compared to women with a body mass index (BMI) of 18.5-27.5 kg/m², those with a BMI <18.5 kg/m² had significantly lower NK cell activity (1356 vs. 1024 g/mL, p<0.001), and those with a BMI ≥27.5 kg/m² tended to have lower NK cell activity (1356 vs. 1119 g/mL, p=0.070). Subjects with high hemoglobin A1c levels and low high-density lipoprotein cholesterol levels, as well as men with high blood pressure and women with high triglyceride levels, exhibited lower NK cell activity. Moreover, physical inactivity and metabolic abnormalities were independently associated with low NK cell activity, even after adjusting for confounders.

CONCLUSION

Physical inactivity and metabolic abnormalities are associated with reduced NK cell activity. Immune systems may become altered depending on physical activity and metabolic status.

Association between natural killer cell activity and the risk of colorectal neoplasia

BACKGROUND AND AIM

Low activity of natural killer (NK) cells is known to be associated with higher risk of cancer, especially with poor prognosis and the presence of colorectal cancer (CRC). We investigated whether NK cells activity differs between subjects with and without colorectal neoplasia (CRN).

METHODS

A cross-sectional study was performed on 1818 asymptomatic examinees aged ≥ 30 years who underwent NK cell activity test (which quantitates the amount of interferon-γ secreted into the plasma by NK cells) and a colonoscopy as part of a health checkup.

RESULTS

The mean age of the study population was 41.4 years. The proportion of overall CRN and advanced CRN was 13.5% (n = 246) and 0.7% (n = 13), respectively. Only one subject was diagnosed with CRC. The median level of NK cell activity was lower in subjects with CRN than in those without CRN (1205 vs 1515 pg/mL, P = 0.009). It was also lower in subjects with non-advanced CRN than in those without CRN (1221 vs 1515 pg/mL; P = 0.036). Moreover, it was lower in subjects with advanced CRN than in those with non-advanced CRN (480 vs 1221 pg/mL; P = 0.028). Subjects with low levels of NK cell activity (< 250 pg/mL) had a higher prevalence of overall CRN (19.0% vs 12.9%, P = 0.024) and advanced CRN (3.4% vs 0.4%, P = 0.001) than those who demonstrated higher level (≥ 250 pg/mL).

CONCLUSIONS

Natural killer cell activity seemed to decrease along with CRC progression toward the later stages in the adenoma-carcinoma sequence. Its activity may be depressed in relation to progression of neoplasia, even at precancerous stage.

Reduced NK cell IFN-γ secretion and psychological stress are independently associated with herpes zoster

The pathogenesis of herpes zoster is closely linked to reduced varicella-zoster virus-specific cell-mediated immunity. However, little is known about the interplay between natural killer cells and psychological stress in the pathogenesis of herpes zoster. This study aimed to investigate possible associations among natural killer cells, T cells and psychological stress in herpes zoster. Interferon-gamma secretion from natural killer cell, psychological stress events, stress cognition scale scores and cytomegalovirus-specific cell-mediated immunity were compared between 44 patients with herpes zoster and 44 age- and gender-matched control subjects. A significantly lower median level of interferon-gamma secreted by natural killer cells was observed in patients with a recent diagnosis of herpes zoster than in control subjects (582.7 pg/ml vs. 1783 pg/ml; P = 0.004), whereas cytomegalovirus-specific cell-mediated immunity was not associated with herpes zoster. Psychological stress events and high stress cognition scale scores were significantly associated in patients with herpes zoster (P<0.001 and P = 0.037, respectively). However, reduced interferon-gamma secretion from natural killer cell and psychological stress were not associated. In conclusion, patients with a recent diagnosis of herpes zoster display reduced interferon-gamma secretion from natural killer cells and frequent previous psychological stress events compared with controls. However, reduced natural killer cell activity is not an immunological mediator between psychological stress and herpes zoster.

Association Between Natural Killer Cell Activity and Colorectal Cancer in High-Risk Subjects Undergoing Colonoscopy

BACKGROUND & AIMS

Low activity of natural killer (NK) cells has been associated with increased risk of cancer and has been reported in patients with colorectal cancer (CRC). Activity of NK cells can be measured in a small volume of whole blood by a commercially available test. We investigated whether this test could be used to identify patients with CRC, using findings from colonoscopy as a reference standard.

METHODS

We performed an open-label, prospective, cross-sectional study of 872 high-risk subjects (more than 40 years old) screened for CRC by colonoscopy at a university hospital in Montreal, Canada from October 2014 through January 2016. Blood samples were collected on the day of colonoscopy, prior to the procedure. The test involves stimulation of whole blood with cytokine that induces NK cells to secrete interferon gamma (IFNG), which is quantified by an ELISA. Tissue samples were taken from lesions during the colonoscopy and analyzed histologically; subjects were classified as having no evidence of disease, adenomatous polyps of less than 10 mm, of 10 mm or more, or CRC. We used the non-parametric Mann-Whitney test to compare NK cell activity between subjects with no evidence of CRC and subjects found to have CRC. Receiver operating characteristic curve analysis was used to assess the ability of the test to identify individuals with CRC. The primary objective was to determine the difference in NK cell activity between subjects with vs without CRC. The secondary objective was the test performance, based on receiver operating characteristic analysis, and cut-off value that most accurately identified individuals with CRC.

RESULTS

We found a significant difference in NK cell activity between the 23 subjects with CRC (based on pathology analysis) and the 849 subjects without CRC: subjects found to have CRC by colonoscopy had a median level of 86.0 pg IFNG/mL (inter-quartile range, 43.3-151.0 pg IFNG/mL), whereas subjects without CRC had a median level of 298.1 pg IFNG/mL (inter-quartile range, 100.4-920.2 pg IFNG/mL) (P = .0002). The cut-off value that most accurately identified subjects with CRC was 181 pg/mL. The NK cell activity test identified subjects with CRC with 87.0% sensitivity, 60.8% specificity, a positive predictive value of 5.7%, and a negative predictive value of 99.4%. The odds ratio for detection of CRC in subjects with low NK cell activity vs subjects with higher NK cell activity was 10.3 (95% CI, 3.03-34.9).

CONCLUSIONS

Using colonoscopy as the reference standard, a test for NK cell activity in whole blood samples identified patients with CRC with 87.0% sensitivity and a negative predictive value of 99.4%. Subjects with low NK cell activity had a 10-fold higher risk of CRC compared with subjects with high NK cell activity. This test might be used in clinical practice to assess patients for risk of CRC. Clinicaltrials.gov number: NCT02291198.

Immunomodulatory potential of nanocurcumin-based formulation

Vitamins, minerals, and nanocurcumin play a substantial role in various nutraceutical/pharmaceutical formulations that are widely used in therapeutics, cosmetics, and dietary supplements. The current study aimed to investigate the comparative in vitro immunomodulatory effect of a novel nanocurcumin-based formulation with curcumin in LPS-induced cytokine expression, NK cells' activity, and phagocytosis. The proinflammatory cytokines (TNF-α, IL-1β, and MIP-1α) and NK cells' activity were measured in cell supernatants using ELISA assay; however, phagocytosis activity was performed using colorimetric analysis. The chemical characterization of novel nanocurcumin-based formulation using LC-MS (R _t 19.02 min) and mass spectra analysis (m/z 369.04) confirmed the presence of the curcumin in highest peak concentration. MTT assay in three tested cell-lines showed that the formulation was found non-toxic at all the tested concentrations. The expression of TNF-α, IL-1β, and MIP-1α in splenocytes was significantly (p ≤ 0.001) inhibited. Besides, the NK cells' activity and phagocytosis (macrophage) were increased significantly (p ≤ 0.001). Overall, the promising results of this study indicated the significant immunomodulatory effect of nanocurcumin-based formulation compared to the curcumin, which could be used against various inflammatory disorders such as allergy, asthma, autoimmune diseases, coeliac disease, inflammatory bowel disease, etc.

Natural killer cell activity for IFN-gamma production as a supportive diagnostic marker for gastric cancer

BACKGROUND/AIM

Decreased Natural killer cell activity (NKA) for interferon-gamma production (NKA-IFNγ) has been reported in cancer patients. The aim of this study was to determine the diagnostic performance of NKA-IFNγ for gastric cancer (GC).

RESULTS

NKA-IFNγ levels were decreased in 261 GC patients with all stages of tumor compared to those in 48 healthy donors (P < 0.001), and lower levels of NKA-IFNγ were associated with higher GC stages. NKA-IFNγ levels were also associated with clinicopathological parameters including tumor size, depth of invasion, and lymph node metastasis. NKA-INFγ assay had better diagnostic value (AUC = 0.822) compared to serum CEA (0.624) or CA19-9 assay (0.566) (P < 0.001). Using different cut-off levels, serum CEA and CA19-9 showed sensitivities of 6.1-14.2% and 4.2-28.0%, respectively, which were much lower than that of NKA-IFNγ (55.6-66.7%).

METHODS

This study included 261 patients with newly diagnosed GC and 48 healthy donors. NKA for IFNγ was determined by enzyme immunoassay after incubation of whole blood, and diagnostic performance was evaluated.

CONCLUSIONS

NK cell activities for IFNγ production could be used as a supportive non-invasive tumor marker for GC diagnosis.

Correlation Between Natural Killer Cell Activity and Systemic Inflammatory Markers for Heterogeneous Cancer Patients Treated With Wheel Balance Cancer Therapy

Background and Objective: Natural killer (NK) cells are known to have an effect on the prevention of tumorigenesis for the initial cancer, as well as the metastatic cancer. For the past several years, the relationship between cancer and inflammation has been actively studied in preclinical and clinical settings, but there are no reports on alterations in and correlation for NK cell activity (NKA) and systemic inflammatory markers. Accordingly, this study aimed to measure correlation between NKA and the levels of other systemic inflammatory markers in patients with gastric, breast, and pancreatic cancer who received Wheel Balance Cancer Therapy (WBCT). Methods: Forty-two electronic charts of patients with gastric, breast, and pancreatic cancer treated with WBCT from February 1, 2015 to September 30, 2015, were reviewed retrospectively. These charts were statistically analyzed, looking for alterations of and correlation for NKA and the expressions of systemic inflammatory markers. Results: Patients with a NKA of under 300 pg/mL at admission showed significantly higher erythrocyte sedimentation rate (ESR) and neutrophil-to-lymphocyte ratio (NLR) values and decreasing NLR values due to WBCT than patients with an NKA greater than 300 pg/mL. As a result of the correlation analysis between NKA and the levels of the systemic inflammatory markers, NKA showed significant negative correlation with NLR, ESR, and fibrinogen values. Conclusions: Negative correlation was identified between NKA and NLR, NKA and ESR, and NKA and fibrinogen in patients with heterogeneous cancer patients.

Establishing the reference intervals of NK cell functions in healthy adults

Natural killer (NK) cells play a key role in host defense against microbial pathogens. Establishing the reference intervals (RIs) of NK cell functions would be valuable in assessing the immune status of hosts. We evaluated the NK cell activity in healthy adults. We further established and validated the RIs of representative NK cell functions. Flow cytometry was used to evaluate the cytokine production and CD107a degranulation of NK cells. Levels of soluble IFN-γ in the culture supernatants were evaluated by ELISA. Our results demonstrated that the intracellular IFN-γ production of NK cells was positively correlated with CD107a expression and soluble IFN-γ levels. There were no significant differences in NK cell functions between different age and gender groups. The mean values and RIs of representative NK cell functions are as following: IFN-γ(+) NK cells (%): 28.09 (11.3-51.95); CD107a(+) NK cells (%): 17.90 (9.852-27.56); soluble IFN-γ (pg/ml): 330.4 (41.38-717.8). In addition, the intracellular IFN-γ production and degranulation activity of NK cells in patients with colorectal cancer were significantly lower than that in healthy adults. Our study has established the RIs of NK cell functions in healthy adults, which might be used for monitoring the immune status of the hosts.

A High-Throughput Assay for Screening of Natural Products that Enhanced Tumoricidal Activity of NK Cells

BACKGROUND

Recently, immunotherapy has shown a lot of promise in cancer treatment and different immune cell types are involved in this endeavor. Among different immune cell populations, NK cells are also an important component in unleashing the therapeutic activity of immune cells. Therefore, in order to enhance the tumoricidal activity of NK cells, identification of new small-molecule natural products is important. Despite the availability of different screening methods for identification of natural products, a simple, economic and high-throughput method is lacking. Hence, in this study, we have developed a high-throughput assay for screening and indentifying natural products that can enhance NK cell-mediated killing of cancer cells.

RESULTS

We expanded human NK cell population from human peripheral blood mononuclear cells (PBMCs) by culturing these PBMCs with membrane-bound IL-21 and CD137L engineered K562 cells. Next, expanded NK cells were co-cultured with non-small cell lung cancer (NSCLC) cells with or without natural products and after 24 h of co-culturing, harvested supernatants were analyzed for IFN-γ secretions by ELISA method. We screened 502 natural products and identified that 28 candidates has the potential to induce IFN-γ secretion by NK cells to varying degrees. Among the 28 natural product candidates, we further confirmed and analyzed the potential of one molecule, andrographolide. It actually increased IFN-γ secretion by NK cells and enhanced NK cell-mediated killing of NSCLC cells.

CONCLUSIONS

Our results demonstrated that this IFN-γ based high-throughput assay for screening of natural products for NK cell tumoricidal activity is a simple, economic and reliable method.