Expression Of NKp46 Research Articles

A High Percentage of DNAM-1+ and Low Percentage of Tactile+ NK Cells at Diagnosis Correlate with Complete Response and Survival in AML: A Sub-Analysis of the Ven-a-Qui Pethema Trial

Background: Natural killer (NK) immune status in Acute Myeloid Leukemia (AML) could influence therapeutic results and natural history of the disease. Objectives: In the phase I/II VEN-A-QUI (Clinical trials NCT04687761) clinical trial for unfit newly diagnosed AML patients (venetoclax+Quizartinib+azacytidine or low-dose cytarabine), it was planned a prospective study of NK populations and their influence in the main clinical outcomes. NK cells were analyzed at the diagnosis in a central laboratory. Material and methods: We analyzed NK cell subpopulations based in the expression of DNAM-1, TIGIT, TACTILE, CD8, PD-1, TIM-3, LAG-3, NKp44, NKp46, NKp30, CD16, CD85j,KIR2D, NKG2C, NKG2A, CD57, CD6, CD244, NKp80, Perforin, Granulolysin and Granzyme B. We compare composite Complete Remission (CRc) results of the Venetoclax/Quizatinib with Aza or Cytarabine vs. not achieving CRc using t Student. MaxStat statistics was used to test the significant limit of those populations with a significant difference (R-statistics version 4.2.2). Survival analysis comparing significant differences between patients in CRc was performed using LogRank test and Kaplan Maier. Cox survival analysis was performed to evaluate if the presence of this populations could be an independent factor against the European Leukemia Net classification of 2017 and p53. Data of molecular characteristics were obtained with an NGS panel of 40 genes. RESULTS: The trial included 76 ineligible patients for intensive chemotherapy (37 and 39 were in Aza and LDAC arms respectively). cCR was obtained in 39 patients (51.3%). ELN2017 risk was favorable in 8, intermediate in 15, and Adverse in 53. In 70 patients NK cell populations were analyzed (4 patients with very low percentage of NK cells, 2 with no sample at diagnosis were excluded from the study). There were significant differences between patients who achieve CRc and those who did not, according to DNAM-1 (74.4% vs 61.9, p=0.0018) and TACTILE (62% vs. 72%, p=0.02) expression on NK cells. The rest of antigens analyzed on NK cells were not significant. We found a cutoff of 62% of DNAM-1+ and less than 81% of TACTILE to differentiate populations in terms of survival using long-rank test. The number of DNAM-1 positive was 47 (60%) and TACTILE- was 55 (78%). The median OS of DNAM-1+ was better than DNAM-1− (18.4 vs 4.7 months, p=0.0001), and between TACTILE− vs TACTILE+ (17,36 vs. 4.6 months, p=0.005). Using an Cox model comparing karyotype, p53 and DNAM-1+ and TACTILE-, only DNAM-1+ was associated with better outcome (HR:0.33 (0.17-0.66) and TACTILE+ with worse (HR: 2.44 (1.20-4.99) in multivariate analysis. Conclusions: DNAM-1(CD226) positive and TACTILE (CD96) negative NK cell populations are associated to CR and better OS. These findings need to be confirmed in larger studies. Interestingly, DNAM-1 is an activating receptor and TACTILE is an inhibitory receptor for NK cells that share the same CD155 ligand but display opposite function.

Gut-microbiota prompt activation of natural killer cell on alcoholic liver disease

ABSTRACT The liver is rich in innate immune cells, such as natural killer (NK) cells, natural killer T cells, and Kupffer cells associated with the gut microbiome. These immune cells are dysfunctional owing to alcohol consumption. However, there is insufficient data on the association between immune cells and gut microbiome in alcoholic liver disease (ALD). Therefore, the purpose of this study was to evaluate the effects of probiotic strains on NK cells in ALD patients. In total, 125 human blood samples [control (n = 22), alcoholic hepatitis (n = 43), and alcoholic cirrhosis (n = 60]) were collected for flow cytometric analysis. C57BL/6J mice were divided into four groups (normal, EtOH-fed, and 2 EtOH+strain groups [Phocaeicola dorei and Lactobacillus helveticus]). Lymphocytes isolated from mouse livers were analyzed using flow cytometry. The frequency of NK cells increased in patients with alcoholic hepatitis and decreased in patients with alcoholic cirrhosis. The expression of NKp46, an NK cell-activating receptor, was decreased in patients with alcoholic hepatitis and increased in patients with alcoholic cirrhosis compared to that in the control group. The number of cytotoxic CD56dimCD16+ NK cells was significantly reduced in patients with alcoholic cirrhosis. We tested the effect of oral administration P. dorei and L. helveticus in EtOH-fed mice. P. dorei and L. helveticus improved liver inflammation and intestinal barrier damage caused by EtOH supply and increased NK cell activity. Therefore, these observations suggest that the gut microbiome may ameliorate ALD by regulating immune cells.

Natural Killer Repertoire Restoration in TB/HIV Co-Infected Individuals Experienced an Immune Reconstitution Syndrome (CAMELIA Trial, ANRS 12153).

IRIS is a common complication in HIV-infected patients treated for tuberculosis (TB) and cART. Our aim was to evaluate NK cell reconstitution in HIV-infected patients with TB-IRIS compared to those without IRIS. 147 HIV-infected patients with TB from the CAMELIA trial were enrolled. HIV+TB+ patients were followed for 32 weeks. The NK cell repertoire was assessed in whole blood at different time points. As CAMELIA has two arms (early and late cART initiation), we analysed them separately. At enrolment, individuals had low CD4 cell counts (27 cells/mm3) and high plasma viral loads (5.76 and 5.50 log/mL for IRIS and non-IRIS individuals, respectively). Thirty-seven people developed IRIS (in the early and late arms). In the early and late arms, we observed similar proportions of total NK and NK cell subsets in TB-IRIS and non-IRIS individuals during follow-up, except for the CD56dimCD16pos (both arms) and CD56dimCD16neg (late arm only) subsets, which were higher in TB-IRIS and non-IRIS individuals, respectively, after cART. Regarding the repertoire and markers of NK cells, significant differences (lower expression of NKp30, NKG2A (CD159a), NKG2D (CD314) were observed in TB-IRIS compared to non-IRIS individuals after the start of cART. In the late arm, some changes (increased expression of CD69, NKG2C, CD158i) were observed in TB-IRIS compared to non-IRIS individuals, but only before cART initiation (during TB treatment). KIR expression by NK cells (CD158a and CD158i) was similar in both groups. CD69 expression by NK cells decreased in all groups. Expression of the NCR repertoire (NKp30, NKp44, NKp46) has similar kinetics in TB-IRIS subjects compared to non-IRIS subjects regardless of the arm analysed. NK cell reconstitution appeared to be better in TB-IRIS subjects. Although NK cell reconstitution is impaired in HIV infection after cART, as previously reported, it does not appear to be affected by the development of IRIS in HIV and TB-infected individuals.

The Association of NKp46-Positive uNK Cells With a Higher Risk of Recurrent Miscarriage and IVF Failure

Background: Uterine natural killer (uNK) cells have a significant impact on pregnancy and related complications. Given the importance of receptors in the activity of uNK cells, the present study aimed to determine the number of uNK cells and NKp46 (one of the most important NK cell-activating receptors) expression in the endometrium of women with recurrent miscarriage (RM) or a history of in vitro fertilization (IVF) failure. Materials and Methods: This case-control study was performed on 48 participants, including 16 healthy controls, 27 cases with RM, and 5 cases with repeated implantation failure (RIF) during the mid-luteal phase according to a standardized diagnostic protocol. All participants were assessed using transvaginal ultrasound to determine embryo survival rate and confirm gestational age. Endometrial specimens were collected and subjected to immunohistochemistry (IHC) staining using an anti-human NKp46 antibody expressed by uNK cells. Results: A significantly higher number of cells positive for NKp46 was obtained among two groups of cases versus healthy subjects (patients: 1.46±0.78, controls: 0.82±62, P=0.006), and the number of CD56+cells was significantly higher in patients than in controls (patients: 18.14±7.14, controls: 11.71±6.17, P=0.003). Additionally, there was not a significant difference in the frequency ratio of NKp46+NK cell subset to CD56+uNK cells between the patients (P=0.59) and control healthy group. Conclusion: The increase in the number of uterine NK cells and their cytotoxic activity during implantation and early pregnancy, possibly resulting from an excessive expression of inflammatory cytokines, confirms a significant association between uNK cell activity and a higher risk of RM and RIF. Therefore, immunomodulatory treatments may benefit these patients.

Methionine enkephalin inhibited cervical cancer migration as well as invasion and activated CD11b+ NCR1+ NKs of tumor microenvironment

This study was to study the role of methionine enkephalin (menk) in cell invasion and migration as well as NK cells activation of tumor microenvironment in cervical cancer. The results showed that menk inhibited cervical cancer migration and invasion. In addition, we found menk affected epithelial to mesenchymal transition (EMT) related indicators, with increasing E-cadherin level, decreasing N-cadherin and vimentin level. Through in vivo mouse model, we found that menk IFNγ and NKP46 expression was upregulated in tumor tissues by menk compared with controls, while LAG3 expression was inhibited by menk, besides, there was an upregulation of CD11b+ NCR1+ NKs of tumor microenvironment in cervical cancer. Therefore, we concluded that menk inhibited cancer migration and invasion via affecting EMT related indicators and activated CD11b+ NCR1+ NKs of tumor microenvironment in cervical cancer, laying a theoretical foundation for the further clinical treatment of menk.

Intratumoral NKp46+ natural killer cells are spatially distanced from T and MHC-I+ cells with prognostic implications in soft tissue sarcoma.

Soft tissue sarcomas (STS) are rare, heterogenous malignancies with an unmet need for novel immunotherapies. Tumor infiltrating lymphocytes (TILs) have been linked with favorable outcomes in STS patients, though the contribution of natural killer (NK) cells and spatial relationships of TILs with MHC-I expressing cells lacks detailed characterization. Using archived and prospectively collected specimens, we evaluated intratumoral NK cells by immunohistochemistry (IHC), flow cytometry, and immunofluorescence (IF). We assessed spatial localization of NK and T cells by multiplex IF, analyzing the effects of MHC-I expression status on NK and T cell clustering. Both intratumoral NKp46 and CD56dim expression were associated with significantly improved overall survival (P=0.05), while higher infiltrates of CD56bright NK cells predicted a worse prognosis (P=0.05). The presence of intratumoral NK cells was inversely proportional to CD3+ T cells. Spatial analyses showed NK cells preferentially clustering close to other NK cells with sparse CD3+ T and CD8+ T cells in range (P<0.0001). Additionally, CD3+ T and CD8+ T cells showed significantly greater co-localization with MHC-I+ cells, compared to NK cells (P<0.0001). After neoadjuvant radiotherapy, there was greater CD8 clustering, while after neoadjuvant chemotherapy, there was overall lower TIL clustering. Intratumoral NK cells are prognostic in STS and localize closer to MHC-I- cells than T cells. Although both NK and T cells are associated with improved survival in STS, their differential distribution in the TME based on MHC-I expression status may serve as a biomarker for improved immunotherapy treatment selection.

NK cell phenotypic profile during active TB in people living with HIV-evolution during TB treatment and implications for bacterial clearance and disease severity

Natural killer (NK) cells, key effector cells of the innate immune system, play an important role in the clearance and control of Mycobacterium tuberculosis and HIV infections. Here, we utilized peripheral blood specimens from the Improving Retreatment Success CAPRISA 011 study to characterize NK cell phenotypes during active TB in individuals with or without HIV co-infection. We further assessed the effects of TB treatment on NK cell phenotype, and characterized the effects of NK cell phenotypes during active TB on mycobacterial clearance and TB disease severity measured by the presence of lung cavitation. TB/HIV co-infection led to the expansion of functionally impaired CD56neg NK cell subset. TB treatment completion resulted in restoration of total NK cells, NK cell subset redistribution and downregulation of several NK cell activating and inhibitory receptors. Higher percentage of peripheral CD56bright cells was associated with longer time to culture conversion, while higher expression of NKp46 on CD56dim NK cells was associated with lower odds of lung cavitation in the overall cohort and the TB/HIV co-infected participants. Together these results provide a detailed description of peripheral NK cells in TB and TB/HIV co-infection and yield insights into their role in TB disease pathology.

Dynamic changes of phenotype and function of natural killer cells in peripheral blood before and after thermal ablation of hepatitis B associated hepatocellular carcinoma and their correlation with tumor recurrence

BackgroundThermal therapy induces an immune response in patients with hepatocellular carcinoma (HCC), but the dynamic characteristics of the natural killer (NK) cell immune response post-thermal ablation remain unclear. We conducted a prospective longitudinal cohort study to observe the dynamic changes of phenotype and function of NK cells in peripheral blood before and after thermal ablation of hepatitis B-associated HCC and their correlation with tumor recurrence.MethodsFifty-six patients clinically and pathologically confirmed with hepatitis B-associated HCC were selected for thermal ablation. Peripheral blood was collected on day 0, day 7, and month 1. NK cell subsets, receptors, and killing function were detected by flow cytometry, and the LDH levels were examined. Overall recurrence and associated variables were estimated using Kaplan–Meier, log-rank, and Cox proportional-hazards analyses.ResultsThe frequency of CD3−CD56+ cells was increased on day 7 (P < 0.01) without significant differences between D0 and M1. NKG2D, NKp44, NKp30, CD159a, and CD158a expression was increased on M1 (all P < 0.05). The granzyme B and IFN-γ expression in NK cells were higher on M1 vs. D0 (P < 0.05). On day 7, the NK cell lysis activity of the target K562 cells was increased (P < 0.01) but decreased on M1 (P < 0.05). Survival analysis showed that CD158a expression and IFN-γ and perforin release on day 0 were associated with the risk of HCC recurrence. Cox regression analysis showed that the expression changes in CD56, NKp46, granzyme B, and perforin (D7-D0) induced by thermal ablation were associated with recurrence-free survival (RFS) of patients with HCC.ConclusionThermal ablation increased the frequency and function of CD3−CD56+ NK cells in the peripheral blood of patients with HCC. These cells tended to be more differentiated and activated. Notably, expression levels of NK cell receptors NKp46, perforin, and granzyme B were associated with RFS.

A Blinded Investigation: Accentuated NK Lymphocyte CD335 (NKp46) Expression Predicts Pregnancy Failures.

NKp46 is an NK cell receptor uniquely expressed by NK cells and a small subset of innate lymphoid cells. In our previous studies, we suggested a tight connection between the activity of NK cells and the expression of NKp46 and supported the clinical significance of NKp46 expression in NK cells in women with reproductive failures. In this study, we investigated the expression of NKp46 in NK cells in the peripheral blood of women in early pregnancy and analyzed its association with pregnancy loss. In a blinded study, we examined blood samples and analyzed the subsequent pregnancy outcomes from 98 early pregnant women (5th-7th week of gestation-w.g.) and 66 women in the 11th-13th week of pregnancy who served as controls. We studied the expression of NKp46 and the levels of anti-cardiolipin antibodies (aCL). The results of aCL were shared with the clinic, while the expression of NKp46 was blinded and not analyzed until the end of the study. A misbalance in the NKp46+NK cells subpopulations was associated with an unfavorable ongoing pregnancy. A decreased level of NKp46high cells (<14%) was strongly associated with miscarriage. A decreased level of the double-bright subpopulation (NKp46hightCD56++) also was a negative prognostic factor for the pregnancy course, but its increased level (>4%) was strongly associated with a successful pregnancy course. Our results showed that accentuated levels of NKp46+NK cells lead to a negative prognosis for early pregnancy courses in women.

Differential expression of immune receptors in pediatric Acute Lymphoblastic Leukemia (ALL)

Abstract Acute Lymphoblastic Leukemia (ALL) represents the most common pediatric cancer. Significant improvements in chemotherapy regimens caused a leap in the 5-year survival rates to surpass 90%. However, relapse significantly lowers the chances of survival to less than 50% in some cases due to resistance developed by malignant cells to chemotherapy. Natural Killer (NK) cells are a promising immunotherapy alternative for their ability to recognize and kill malignant cells directly through activation or inhibition signals or through cytokine release. We have previously identified 2B4 (SLAMF4), CS1 (SLAMF7) and LLT1 that can activate or inhibit NK cells upon the interaction with their ligands. In this study, the expression of 2B4, CS1, LLT1, NKp30 and NKp46 was determined in pediatric ALL and healthy subjects. Whole blood was collected from 42 pediatric ALL subjects before and after induction chemotherapy and the surface expression of receptors/ligand on T-cells, B-cells, monocytes, and NK-cells was compared with blood samples from 20 healthy subjects. The flow cytometry data showed a significant increase in CS1 and NKp46 expression on monocytes and LLT1 in T cells and monocytes of ALL subjects before treatment. A decrease of LLT1, 2B4, CS1 and NKp46 on T-cells of ALL subjects was also observed after treatment along with elevated expression of LLT1 on ALL subjects’ NK-cells before and after treatment. Furthermore, mRNA data showed altered expression of receptors in ALL subjects pre and post induction chemotherapy treatment. The results indicate that the differential expression of the receptors/ligand may play a role in the T cell and NK-cell mediated immune surveillance of pediatric ALL. Supported by funds from Cancer Research Foundation of North Texas and Team Connor Childhood Cancer Foundation

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

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

CARD11 dominant negative mutation leads to altered human Natural Killer cell homeostasis

Dominant negative mutations in CARD11 have been reported in patients with immune dysregulation, severe atopic features, and variable T cell alterations. Data on Natural killer (NK) cells from affected patients are lacking. We report on a 12-year-old boy with severe atopic dermatitis, food induced anaphylaxis and hypogammaglobulinemia harbouring a novel de novo heterozygous variant c.169G > A; p.Glu57Lys in CARD11. The dominant negative effect of this mutation was confirmed on both CD4+ and CD8+. CTLA4+Foxp3+CD4+ Tregs were severely reduced. Patient’s NK cells showed reduced expression of NKp46, NKG2D and CD69. Patient’s CD56bright NK cells showed in vitro impaired production of IFN-γ. Steady state pS6 levels on patient’s NK cells were increased and remained elevated upon IL2 + IL12 + IL18 overnight stimulation. Overall, the effect of CARD11 mutation on mTORC1 differs between T and NK cells. These findings may explain the increased susceptibility to viral infections and the reduced immune surveillance in affected patients.

Immature and activated phenotype of blood NK is associated with acute rejection in adult liver transplant.

Natural killer (NK) cells contribute to liver transplant (LTx) rejection. However, the blood-circulating NK cell dynamics of patients who experience acute rejection (AR) are unclear. Herein, we longitudinally profiled the total NK cells and their subsets, along with the expression of activating and inhibitory receptors in sequential peripheral blood mononuclear cells samples, spanning from pre-LTx to the first year post-LTx of 32 patients with AR and 30 patients under a steady immune status. Before transplantation, patients with AR (rejectors) contained a significantly higher proportion of the immature CD56brightCD16- subset and a lower cytolytic CD56dimCD16+ in the total blood-circulating NK cells than patients with steady immunity. Both subsets contained a high NKp30 positive population, and CD56dimCD16+ additionally exhibited a high NKp46 positive ratio. The NKp30 positive ratio in CD56dimCD16+ subset showed the most prominent AR predictive ability pre-LTx, and was an independent risk factor of LTx AR. After transplantation, the blood-circulating NK cells in rejectors maintained a higher CD56brightCD16- and lower CD56dimCD16+ composition than the controls throughout the first year post-LTx. Moreover, both subsets maintained a high NKp30 positive ratio, and CD56dimCD16+ retained a high NKp46 positive ratio. The blood-circulating NK-cell subset composition was consistent during AR, while the expressions of NKp30 and NKp46 were augmented. Collectively, a more immature CD56brightCD16- subset composition and an activated phenotype of high NKp30 expression were the general properties of blood-circulating NK cells in rejected LTx recipients, and the NKp30 positive ratio in CD56dimCD16+ NK subset pre-LTx possessed AR predictive potential.

Dl-THP recovered the decreased NKp44 expression level on CD56dim CD16+ natural killer cells partially in choriocarcinoma microenvironment

Natural killer cell-based immunotherapy has become a leading-edge tool against cancer, but still faces a variety of challenges, such as phenotype shift and dysfunction of NK cells in tumor microenvironment. Thus, finding potent agents that could inhibit the phenotype shift and incapacity of NK cells in the tumor microenvironment is essential for improving antitumor effects. dl-tetrahydropalmatine (dl-THP), one of the active alkaloids of Chinese herb Corydalis Rhizoma, has been proven to possess antitumor activity. However, whether dl-THP acts on NK cells to enhance antitumor activity remains unknown. In this study, we found that the proportion of blood CD56dimCD16+ NK cells was decreased while the proportion of CD56brightCD16- NK cells was increased when the cells were cultured in conditional medium (CM, medium from the human choriocarcinoma cell lines JEG-3). dl-THP could alter the varied proportion of CD56dimCD16+ NK cells and CD56brightCD16- NK cells in CM respectively. Importantly, the expression level of NKp44 on CD56dimCD16+ NK cells was dramatically reduced when the cells were cultured in CM, which could also be reversed by dl-THP. Furthermore, dl-THP increased the decreased NK-cell cytotoxicity when cells were cultured in CM. In summary, our study demonstrated that dl-THP could recover the decreased NKp44 expression level on CD56dimCD16+ NK cells and restore the cytotoxicity of NK cells in tumor microenvironment.

Differential Expression of LLT1, SLAM Receptors CS1 and 2B4 and NCR Receptors NKp46 and NKp30 in Pediatric Acute Lymphoblastic Leukemia (ALL).

Acute lymphoblastic leukemia (ALL) represents the most common pediatric cancer. Most patients (85%) develop B-cell ALL; however, T-cell ALL tends to be more aggressive. We have previously identified 2B4 (SLAMF4), CS1 (SLAMF7) and LLT1 (CLEC2D) that can activate or inhibit NK cells upon the interaction with their ligands. In this study, the expression of 2B4, CS1, LLT1, NKp30 and NKp46 was determined. The expression profiles of these immune receptors were analyzed in the peripheral blood mononuclear cells of B-ALL and T-ALL subjects by single-cell RNA sequencing data obtained from the St. Jude PeCan data portal that showed increased expression of LLT1 in B-ALL and T-ALL subjects. Whole blood was collected from 42 pediatric ALL subjects at diagnosis and post-induction chemotherapy and 20 healthy subjects, and expression was determined at the mRNA and cell surface protein level. A significant increase in cell surface LLT1 expression in T cells, monocytes and NK cells was observed. Increased expression of CS1 and NKp46 was observed on monocytes of ALL subjects at diagnosis. A decrease of LLT1, 2B4, CS1 and NKp46 on T cells of ALL subjects was also observed post-induction chemotherapy. Furthermore, mRNA data showed altered expression of receptors in ALL subjects pre- and post-induction chemotherapy treatment. The results indicate that the differential expression of the receptors/ligand may play a role in the T-cell- and NK-cell-mediated immune surveillance of pediatric ALL.

Alterations in the immune system persist after one year of convalescence in severe COVID-19 patients.

Severe COVID-19 originates a myriad of alterations in the immune system during active disease, especially in the T and NK cell compartments, but several studies in the last year have unveiled some alterations that persist in convalescence. Although most of the studies follow the participants for a short recovery time, studies following patients up to three or six months still find alterations. We aimed at evaluating changes in the NK, T and B cell compartments after severe COVID-19 in participants with a median recovery time of eleven months. Eighteen convalescent of severe COVID-19 (CSC), 14 convalescent of mild COVID-19 (CMC) and nine controls were recruited. NKG2A, NKG2C, NKG2D and the activating receptor NKp44 were evaluated in NKbright, NKdim and NKT subpopulations. In addition, CD3 and CD19 were measured and a basic biochemistry with IL-6 levels was obtained. CSC participants showed lower NKbright/NKdim ratio, higher NKp44 expression in NKbright subpopulations, higher levels of serum IL-6, lower levels of NKG2A+ T lymphocytes and a trend to a lower expression of CD19 in B lymphocytes compared to controls. CMC participants showed no significant alterations in the immune system compared to controls. These results are concordant with previous studies, which find alterations in CSC weeks or months after resolution of the symptoms, and point to the possibility of these alterations lasting one year or more after COVID-19 resolution.

The inhibitory NKR-P1B receptor regulates NK cell-mediated mammary tumor immunosurveillance in mice

ABSTRACT Natural killer (NK) cells are an important component of anti-cancer immunity, and their activity is regulated by an array of activating and inhibitory receptors. In mice, the inhibitory NKR-P1B receptor is expressed in NK cells and recognizes the C-type lectin-related protein-b (Clr-b) ligand. NKR-P1B:Clr-b interactions represent a ‘missing-self’ recognition system to monitor cellular levels of Clr-b on healthy and diseased cells. Here, we report an important role for NKR-P1B:Clr-b interactions in tumor immunosurveillance in MMTV-PyVT mice, which develop spontaneous mammary tumors. MMTV-PyVT mice on NKR-P1B-deficient genetic background developed mammary tumors earlier than on wild-type (WT) background. A greater proportion of tumor-infiltrating NK cells downregulate expression of the transcription factor Eomesodermin (EOMES) in NKR-P1B-deficient mice compared to WT mice. Tumor-infiltrating NK cells also downregulated CD49b expression but gain CD49a expression and exhibit effector functions, such as granzyme B upregulation and proliferation in mammary tumors. However, unlike the EOMES+ NK cells, the EOMES‒ NK cell subset is unable to respond to further in vitro stimulation and exhibits phenotypic alterations associated with immune dysfunction. These alterations included increased expression of PD-1, LAG-3, and TIGIT and decreased expression of NKp46, Ly49C/I, CD11b, and KLRG-1. Furthermore, tumor-infiltrating NKR-P1B-deficient NK cells exhibited an elevated dysfunctional immune phenotype compared to WT NK cells. These findings demonstrate that the NKR-P1B receptor plays an important role in mammary tumor surveillance by regulating anti-cancer immune responses and functional homeostasis in NK cells.

Identification of the CD16low CD56low CD38pos Natural Killer Cell as a Key Subset in Patients with Multiple Myeloma.

Natural killer (NK) cells are classified as innate immune cells which can directly recognize and kill tumor cells without antigen sensitization. NK cell-based adoptive immunotherapy for blood malignancies has attracted more attention in recent years. To analyze different NK cell subsets in the peripheral blood and bone marrow (BM) of patients with multiple myeloma (MM). Using flow cytometry we analyzed: (i) the distribution of distinct NK cell subpopulations (i.e. CD16low CD56low, CD16pos CD56high, CD16neg CD56high, CD16high CD56low, CD16neg CD56low, CD16low CD56low CD38pos) in the BM from MM patients at distinct disease stages. (ii) the expression of NKG2D, DNAM-1 and NKp30, and (iii) the expression of CD107a in CD16low CD56low CD38pos and CD16low CD56low CD38neg NK cells subsets. CD16low CD56low CD38pos was the dominant subset in BM from patients with MM at the CR stage with a decreased expression of NKp30. CD16low CD56low CD38pos subset showed a higher proportion of CD107a expression compared to CD16low CD56low CD38neg cells. In vitro experiments indicated that the CD16low CD56low CD38pos NK cell subset possesses more cytotoxicity than CD16low CD56low CD38neg NK cells. Our data suggest that CD16low CD56low CD38pos NK cells may reflect as an effector population with the potential therapeutic target in patients with MM. This group of cells may be useful for adoptive immunotherapy in MM in the future.

Co-expression of activating and inhibitory receptors on peritoneal fluid NK cells in women with endometriosis

The detailed mechanism underlying endometriosis development remains unclear; few reports have suggested the involvement of immune and genetic factors. This study aims to investigate the role of NK cells in endometriosis by analyzing the co-expression of activating (NKp46, NKG2C, and NKG2D) and inhibitory receptors (NKG2A and CD158a) on NK cells and their subsequent cytokine production in the peritoneal fluid (PF). Sixty-two patients were enrolled for this study from Hyogo Medical University between February 2018 and April 2022. Results showed that the proportions of CD56+/NKp46+, CD56dim/NKp46＋, NKG2C＋/NKp46＋, and NKG2D＋/NKp46＋ NK cells were significantly lower in the endometriosis group than those in the control group. Meanwhile, within the peritoneal endometriosis (n = 21) and deep infiltrating endometriosis (n = 11) groups, the co-expression of NKG2D＋/NKp46＋ and CD16＋/NKp46＋. Additionally, the abundance of IFN-γ-producing NK cells was significantly increased in the endometriosis group compared to controls, and a significant negative correlation was noted between NKp46 expression on NK cells and type 1 cytokine (IFN-γ and TNF-α) production. Taken together, the findings of this study indicate that NK cell cytotoxicity in endometriosis is reduced due to changes in NKp46 expression, as well as activating receptors co-expressed with NKp46. Consequently, NK cells do not eliminate endometrial cells in the abdominal cavity, resulting in the production of TNF-α and IFN-γ.

Bone Marrow Microenvironment Changes in Myelodysplastic Neoplasms and Its Relationship with Clonal Hematopoiesis and Disease Progression

Background: Immune dysregulation and somatic gene mutations are known prognostic factors in myelodysplastic neoplasms (MDS). During the evolution of the disease, a decrease in the immune surveillance is observed, with impaired cytotoxicity and a decrease in mature natural killer cells (NK), among other changes. Also, over expression of inflammatory cytokines, plays a role in the immune environment. The interaction between immune populations and the malignant clone is not entirely understood, especially in the bone marrow. The aims of this study were to characterize bone marrow (BM) immune populations, especially NK cells, and its correlation with the malignant clone. Methods: We prospectively collected 70 BM samples. Fifty MDS without RS or 5q deletion, 11 cytopenia of unknown significance (CUS) and 9 healthy donors (HD). The aims were to analyze NK cells, defined as (CD45+CD3-CD19-) and differentiating an immature population (CD56brigthCD16−NKG2A/CD94+KIR+/−) from a mature one (CD56dim CD16+NKG2A/CD94−KIR+). Their different receptors: activators (NKp46, NKp30, NKG2C, NKG2D, NKp44, DNAM) and inhibitors (TIGIT, NKG2A, Irp60, and PD1), as well as clonal cells expression of their ligands (HLA-ABC, MICA-B, CD155, PD-L1). Finally, KIR haplotype was analyzed, by NGS. Other populations included were myeloid-derived suppressor cells (MDSC), differentiating granulocytic (Gr-MDSC: CD11b+CD33+HLA-DR-CD15+CD14-) and monocytic (Mo-MDSC:CD11b+CD33+ HLA-DRlow/CD15+ CD14+). The analysis was performed, by flow cytometry, on BM fresh samples, following a membrane staining protocol with 10-colors/3 lasers. Molecular analysis was performed by NGS using the Oncomine Myeloid Research Assay included 40 genes. Finally, cytokines concentrations were stablished with the commercial kit ProcartaPlexTM Multiplex immunoassay. Results: A total of 70 subjects (median age of 77 years old and 45% female) were included (Figure 1). Although, total NK was similar among the three groups [MDS 0.17x109/L ICUS 0.07x109/L, HD 0.20x109/L, p= 0.1204], we observed differences between NK subpopulations. An increase of mature NK cells CD56dimCD16+ in CUS (76.16%) compared with MDS (11.58%) and HD (13.67%) [p= 0.0005] was observed. Regarding NK activating receptors, DNAM receptor was highly expressed on MDS (96.05%) and HD (90.98%), compared to CUS (67.79%) [p= 0.007], and the expression of KIR2DS4 was decreased in MDS (28.47%) compared to HD (79.4%) [p= 0.005], as well as NKp44 on MDS (0.19%) compared with HD (0.34%) [p= 0.03]. Interestingly, no expression of KIR2DS4 or NKp44 were observed on CUS. Regarding inhibitor receptors, Irp60 was increased on MDS (95.52%) compared to CUS (85.07%) and HD (80.2%) [p= 0.036] (Figure 2). Inhibitory KIR haplotype AA was observed on 13/47 MDS (27.56%). Finally, no differences were observed between Gr-MDSC [MDS 0.51%, ICUS 0.13%, HD 0.33%, p=0.35] or Mo-MDSC [MDS 1.03%, ICUS 0.25%, HD 0.7%, p=0.28] expression, among groups. Eighty-four percent (42/50) of MDS presented mutations at diagnosis, with a median number of 3. Interestingly, 63.6% (7/11) of CUS presented mutations, 2 DMT3A (VAF < 5%), 1 TET2 (VAF 40%), 1 IDH1 and 1 SF3B1 (VAF 33%), among others. Within subjects presenting mutations, we observed differences on the expression of NKG2A, showing an increase on those with ≥3 mutations (37.23%) vs <3 mutations (35.3%) [p=0.02]. Moreover, differences were found on KIR2DL1 [≥3 mutations 6.66% vs <3 mutations 15.61%, p=0.05]. On the 7 clonal cytopenia of unknown significance (CCUS), no differences were found on the expression of NK receptors compared to idiopathic cytopenia of unknown significance (ICUS). Cytokine analysis on BM of 39 MDS, showed increased levels of IL-10 in HR compared to LR [2 pg/ml vs. 1 pg/ml, p=0.04], including 16 (53%) subjects with very high concentrations (> 40 pg/ml). In addition, we analyzed NK cells of 14 MDS subjects who had a second BM sample, one year after diagnosis. We documented an increase in CD244 NK population [15.23% follow-up vs 3.61% diagnosis, p=0.05]. Conclusions: Our study suggests the presence of immunosuppressive profile of NK cells on MDS, with gain of expression of NKG2A and higher expression of IL10 on high risk MDS. Interestingly, 63.6% CUS subjects were CCUS and showed increase cytotoxic profile. The increase of CD244 expression, at one year control, may be related to an exhausted environment leading to immunosuppression and progression. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal