Increased natural killer T-like cells are a major source of pro-inflammatory cytokines and granzymes in lung transplant recipients

Contradictory Effect of Lymphocyte Therapy and Prednisolone Therapy on CD3+CD8+CD56+ Natural Killer T Population in Women with Recurrent Spontaneous Abortion

Background

Natural killer T (NKT) cells are influential immune cells in pregnancy failures, including recurrent spontaneous abortion (RSA). Different approaches are used for these disorders due to their effects on maternal immunomodulation.

Aims

In the present study, we compared the effects of two typical immunotherapies (lymphocyte immunotherapy [LIT] and low-dose prednisolone) on CD3+CD56+CD16+ and CD3+CD56+CD8+ cells as two distinct subsets of NKT cells in Women with RSA.

Settings and Design

This study was a comparative cohort study conducted from 2021 to 2022. One hundred and five women with RSA were distributed into three treatment groups randomly.

Materials and Methods

Fifty women in the group of low-dose prednisolone therapy, fifty women in the LIT group and five women without any treatment as the control group were included in the study. NK and NKT cell subsets were assessed using flow cytometry. Furthermore, the concentration of interferon-gamma (IFN-γ), transforming growth factor-beta (TGF-β) and interleukin-10 (IL-10) was measured quantitatively using the enzyme-linked immunosorbent assay technique.

Statistical Analysis Used

Normality and comparisons between study groups were performed by non-parametric unpaired Mann-Whitney, Kruskal-Wallis rank sum test, and one-way ANOVA.

Results

The percentage of CD56dim NK cells was increased after prednisolone therapy, while this population significantly decreased in the LIT group. In contrast to the LIT group, the administration of prednisolone increased CD3+CD8+CD56+ NKT cells (P < 0.0001), which is helpful for pregnancy. The effect of the investigated treatment approaches on the population of peripheral CD3+CD56+CD16+ NKT cells of women with RSA was not adequately significant. The same situation was also observed regarding the serum level of IFN-γ. However, a significant decrease in serum levels of IL-10 and TGF-β was observed after prednisolone therapy.

Conclusion

The lower capability of LIT in changing the population of NKT cells compared to prednisolone therapy may be due to its mechanism of action, which is related to the production of blocking antibodies. These treatment approaches had different effects on NKT cells, indicating that NKT cell population and function can be affected using LIT and prednisolone therapy distinctly. In addition, prednisolone therapy and LIT in women with normal serum levels of IFN-γ have no harmful effects in changing the production of this critical cytokine.

Cytokines in Lung Transplantation

Lung transplantation has developed significantly in recent years, but post-transplant care and patients' survival still need to be improved. Moreover, organ shortage urges novel modalities to improve the quality of unsuitable lungs. Cytokines, the chemical mediators of the immune system, might be used for diagnostic and therapeutic purposes in lung transplantation. Cytokine monitoring pre- and post-transplant could be applied to the prevention and early diagnosis of injurious inflammatory events including primary graft dysfunction, acute cellular rejection, bronchiolitis obliterans syndrome, restrictive allograft syndrome, and infections. In addition, preoperative cytokine removal, specific inhibition of proinflammatory cytokines, and enhancement of anti-inflammatory cytokines gene expression could be considered therapeutic options to improve lung allograft survival. Therefore, it is essential to describe the cytokines alteration during inflammatory events to gain a better insight into their role in developing the abovementioned complications. Herein, cytokine fluctuations in lung tissue, bronchoalveolar fluid, peripheral blood, and exhaled breath condensate in different phases of lung transplantation have been reviewed; besides, cytokine gene polymorphisms with clinical significance have been summarized.

Phenotypic characterization of NKT-like cells and evaluation of specifically related cytokines for the prediction of unexplained recurrent miscarriage

Problem

Immune system dysregulation is a major cause of unexplained recurrent miscarriage (URM). Women with URM need screening for their pregnancy microenvironment and immune regulators, to prevent spontaneous abortion.

Method of study

In this study we evaluated NKT-like cell subsets in peripheral venous blood of women with URM using flow cytometry. The expression levels of specifically related Th1 cytokines (IFN-γ and IL-2), Th2 cytokine (IL-4), and Th17 cytokines (IL-17), were measured using enzyme-linked immunosorbent assay.

Results

The percentage of CD16+CD56+NKT-like (Double Positive NKT-like; DPNKT-like) cell subset, and the levels of IL-2 and IFN-γ were significantly elevated in blood of non-pregnant and pregnant patients with URM compared with the healthy control groups, and these parameters were significantly increased after pregnancy in the same patients with URM. Based on the prevalence of the candidate immunological factors in patients with URM, the prognostic significance of the NKT-like cell subsets, IFN-γ and IL-2 profiles were evaluated as potential predictors of URM. A cut-off point of 2.55% for DPNKT-like cell subset in the blood and cut-off values of 39.5 and 20.5 pg/ml for the levels of IFN-γ and IL-2, respectively could be used for the prediction of the risk of spontaneous abortion. To the best of our knowledge, this is the first study that described the prognostic significance of the aforementioned immunological parameters before and after pregnancy, and highlighted the correlation of NKT-like cells and the candidate Th1 cytokines with pregnancy loss in women with URM.

Conclusions

DPNKT-like cells, IFN-γ and IL-2 patient profiles could be used as markers to predict the risk of miscarriage in patients with URM.

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Disturbance in the immune system's regulators is an essential factor for recurrent miscarriage.

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There is an urgent need for women who have suffered pregnancy loss to identify specific immune regulators that underline recurrent miscarriage, to prevent and control miscarriage.

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CD16+CD56+NKT-like cells, Interferon-γ and Interleukin-2 patient profile could be utilized as biomarkers to predict risk of miscarriage in women who have suffered spontaneous miscarriage.

Challenges in the use of highly effective modulator treatment for cystic fibrosis

The last decade has seen development of oral, small molecule therapies that address the basic cystic fibrosis transmembrane conductance regulator (CFTR) protein defect. Highly effective modulator treatment (HEMT) that is efficacious for a large majority of people living with cystic fibrosis (CF) promises to change the landscape of this chronic life-limiting disease. Some people living with CF have a CFTR genotype that renders them eligible for HEMT, but also have comorbidities that excluded them from the original Phase III clinical trials that led to US Food and Drug Administration approval. The purpose of this review is to address the use of HEMT in challenging situations, including initiation for those with advanced CF lung disease, and use after solid organ transplant, during pregnancy, and for individuals with CFTR-related disorders without a definitive diagnosis of CF.

Bronchiolitis obliterans syndrome is associated with increased senescent lymphocytes in the small airways

BACKGROUND

Immunosuppression therapy is ineffective at preventing bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways (SAs). Our previous reports show increased senescent CD28null T and natural killer T (NKT)-like cells in the peripheral blood of patients with BOS and increased cytotoxic, proinflammatory lymphocytes in the SAs. We hypothesized that the cytotoxic, proinflammatory lymphocytes in the SAs would be steroid-resistant senescent CD28null lymphocytes.

METHODS

Intracellular cytotoxic mediator granzyme B, interferon (IFN)-γ and tumor necrosis factor (TNF)-α proinflammatory cytokines, and CD28 were measured in the blood, bronchoalveolar lavage, large airway, and SA brushing T and NKT-like cells from 10 patients with BOS, 11 stable lung transplant recipients, and 10 healthy age-matched controls. SA brushings were cultured in the presence of ±1 µmol/liter prednisolone, ±5 mg/liter theophylline, and ±2.5 ng/ml cyclosporine A, and IFN-γ and TNF-α proinflammatory cytokines were assessed using flow cytometry.

RESULTS

Increased SA CD28null T and NKT-like cells were identified in patients with BOS compared with that in the controls and stable transplant recipients. Loss of CD28 was associated with increased T and NKT-like cells expressing granzyme B, IFN-γ, and TNF-α. Loss of CD28 expression by CD8+ T cells was significantly associated with forced expiratory volume in 1 sec (R = 0.655, p = 0.006) and with time after transplantation (R = -0.552, p = 0.041). Treatment with prednisolone + theophylline + cyclosporin A inhibited IFN-γ and TNF-α production by SA CD28null CD8+ T and NKT-like cells additively.

CONCLUSIONS

BOS is associated with the loss of CD28 in SA cytotoxic, proinflammatory senescent T and NKT-like lymphocytes. Treatment options that target the proinflammatory nature of these cells in the SAs may improve graft survival.

Adenosine A2A receptor agonist (regadenoson) in human lung transplantation

BACKGROUND

Currently, there are no clinically approved treatments for ischemia-reperfusion injury after lung transplantation. Pre-clinical animal models have demonstrated a promising efficacy of adenosine _2A receptor (A_2AR) agonists as a treatment option for reducing ischemia-reperfusion injury. The purpose of this human study, is to conduct a Phase I clinical trial for evaluating the safety of continuous infusion of an A_2AR agonist in lung transplant recipients.

METHODS

An adaptive, two-stage continual reassessment trial was designed to evaluate the safety of regadenoson (A_2AR agonist) in the setting of lung transplantation. Continuous infusion of regadenoson was administered to lung transplant recipients that was started at the time of skin incision. Adverse events and dose-limiting toxicities, as pre-determined by a study team and assessed by a clinical team and an independent safety monitor, were the primary end-points for safety in this trial.

RESULTS

Between January 2018 and March 2019, 14 recipients were enrolled in the trial. Of these, 10 received the maximum infused dose of 1.44 µg/kg/min for 12 hours. No dose-limiting toxicities were observed. The steady-state plasma regadenoson levels sampled before the reperfusion of the first lung were 0.98 ± 0.46 ng/ml. There were no mortalities within 30 days.

CONCLUSIONS

Regadenoson, an A_2AR agonist, can be safely infused in the setting of lung transplantation with no dose-limiting toxicities or drug-related mortality. Although not powered for the evaluation of secondary end-points, the results of this trial and the outcome of pre-clinical studies warrant further investigation with a Phase II randomized controlled trial.

SPECT imaging of lung ischemia-reperfusion injury using [99mTc]cFLFLF for molecular targeting of formyl peptide receptor 1

Primary graft dysfunction after lung transplantation, a consequence of ischemia-reperfusion injury (IRI), is a major cause of morbidity and mortality. IRI involves acute inflammation and innate immune cell activation, leading to rapid infiltration of neutrophils. Formyl peptide receptor 1 (FPR1) expressed by phagocytic leukocytes plays an important role in neutrophil function. The cell surface expression of FPR1 is rapidly and robustly upregulated on neutrophils in response to inflammatory stimuli. Thus, we hypothesized that use of [^99mTc]cFLFLF, a selective FPR1 peptide ligand, would permit in vivo neutrophil labeling and noninvasive imaging of IRI using single-photon emission computed tomography (SPECT). A murine model of left lung IRI was utilized. Lung function, neutrophil infiltration, and SPECT imaging were assessed after 1 h of ischemia and 2, 12, or 24 h of reperfusion. [^99mTc]cFLFLF was injected 2 h before SPECT. Signal intensity by SPECT and total probe uptake by gamma counts were 3.9- and 2.3-fold higher, respectively, in left lungs after ischemia and 2 h of reperfusion versus sham. These values significantly decreased with longer reperfusion times, correlating with resolution of IRI as shown by improved lung function and decreased neutrophil infiltration. SPECT results were confirmed using Cy7-cFLFLF-based fluorescence imaging of lungs. Immunofluorescence microscopy confirmed cFLFLF binding primarily to activated neutrophils. These results demonstrate that [^99mTc]cFLFLF SPECT enables noninvasive detection of lung IRI and permits monitoring of resolution of injury over time. Clinical application of [^99mTc]cFLFLF SPECT may permit diagnosis of lung IRI for timely intervention to improve outcomes after transplantation.

IL-17 production by NKG2D-expressing CD56+ T cells in type 2 diabetes

T cells expressing CD56 (identified as CD3+CD56+) play a potential role in activation or regulation of other immune cells by secreting various cytokines. We hypothesized that these cells expressing the natural group 2, member D (NKG2D) could produce high levels of interleukin (IL)-17 in type 2 diabetes (T2D). CD56 + T cells expressing NKG2D of T2D patients, particularly in poor glycemic control (PC) predominantly produced higher IL-17 compared to the NKG2D negative population. IL-17 production of CD56 + T cells with NKG2D + was positively correlated with the level of HbA1c (N = 22, R² = 0.120 and P =  0.044). Interestingly, CD56+ T cells with NKG2D^Hi of T2D patients had significantly higher IL-17 production than those of CD56 + T cells with NKG2D^Low (P =  0.027) and showed statistically significant with P-value < 0.001 compared to CD56 + T cells with NKG2D^Hi of non-diabetic individuals (ND). In summary, CD56 + T cells expressing NKG2D, especially in the NKG2D^Hi population may be involved in pathogenesis and severity of T2D via IL-17.

BOS is associated with decreased HDAC2 from steroid resistant lymphocytes in the small airways

Immunosuppression therapies including corticosteroids fail to prevent bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways, following lung transplantation. We reported increases in steroid-resistant proinflammatory lymphocytes and their loss of histone deacetylase 2 (HDAC2), an important mediator of steroid action, in the blood of stable lung transplant recipients. We noted similar increases in the steroid-resistant lymphocytes in both the blood and small airways in BOS compared with the large airways. We hypothesized that these small airway cells would also exhibit a loss of HDAC2, and that these changes could be reversed by treatment with theophylline (HDAC2 activator). Blood, bronchoalveolar lavage and large and small airway brushings were collected from lung transplant patients with BOS (n = 12) or stable lung function (n = 18) and healthy aged-matched controls (n = 13). Intracellular proinflammatory cytokines [interferon (IFN-γ) and tumour necrosis factor (TNF)-α and HDAC2 were measured in CD8⁺ T, natural killer (NK) T-like and NK cells from cultured small airway brushings ± 5 mg/l theophylline ± 1 µM prednisolone using flow cytometry. Increased small airway CD8 T, NK T-like and NK cells were identified in BOS versus stable transplant and controls. In BOS, these cells exhibited increased IFN-γ/TNF-α and a loss of HDAC2. HDAC2 expression by small airway CD8⁺ T cells correlated with forced expiratory volume in 1 s (FEV₁ ) (R = 0·880, P = 0·031). Theophylline and prednisolone synergistically up-regulated HDAC2 in CD8⁺ T cells. BOS is associated with loss of HDAC2 from steroid-resistant proinflammatory CD8⁺ T, NK T-like and NK cells in the small airways. Therapeutically increasing HDAC2 in these lymphocytes may reduce steroid resistance and improve graft survival.

Pannexin-1 channels on endothelial cells mediate vascular inflammation during lung ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury (IRI), which involves inflammation, vascular permeability, and edema, remains a major challenge after lung transplantation. Pannexin-1 (Panx1) channels modulate cellular ATP release during inflammation. This study tests the hypothesis that endothelial Panx1 is a key mediator of vascular inflammation and edema after I/R and that IRI can be blocked by Panx1 antagonism. A murine hilar ligation model of IRI was used whereby left lungs underwent 1 h of ischemia and 2 h of reperfusion. Treatment of wild-type mice with Panx1 inhibitors (carbenoxolone or probenecid) significantly attenuated I/R-induced pulmonary dysfunction, edema, cytokine production, and neutrophil infiltration versus vehicle-treated mice. In addition, VE-Cad-CreERT2+/Panx1fl/fl mice (tamoxifen-inducible deletion of Panx1 in vascular endothelium) treated with tamoxifen were significantly protected from IRI (reduced dysfunction, endothelial permeability, edema, proinflammatory cytokines, and neutrophil infiltration) versus vehicle-treated mice. Furthermore, extracellular ATP levels in bronchoalveolar lavage fluid is Panx1-mediated after I/R as it was markedly attenuated by Panx1 antagonism in wild-type mice and by endothelial-specific Panx1 deficiency. Panx1 gene expression in lungs after I/R was also significantly elevated compared with sham. In vitro experiments demonstrated that TNF-α and/or hypoxia-reoxygenation induced ATP release from lung microvascular endothelial cells, which was attenuated by Panx1 inhibitors. This study is the first, to our knowledge, to demonstrate that endothelial Panx1 plays a key role in mediating vascular permeability, inflammation, edema, leukocyte infiltration, and lung dysfunction after I/R. Pharmacological antagonism of Panx1 activity may be a novel therapeutic strategy to prevent IRI and primary graft dysfunction after lung transplantation.

Diminished Frequency of Menstrual and Peripheral Blood NKT-Like Cells in Patients With Unexplained Recurrent Spontaneous Abortion and Infertile Women

Systemic monitoring of immune system may not precisely outline the local immune status in the uterus. This survey is a continuation of our previous studies on potential usefulness of menstrual blood (MB) immunophenotyping as a tool for investigation of immunological disturbances in pregnancy-related disorders. Peripheral blood (PB) and MB from healthy fertile (n = 15), unexplained recurrent spontaneous abortion (URSA; n = 15), and unexplained infertile women (n = 8) were collected simultaneously in the second day of their menstrual cycle and frequency of natural killer T (NKT)-like cell subpopulations were assessed by flow cytometry. Menstrual blood of all experimental groups contained higher percentage of TCRαβ⁺, CD45RO⁺, and CD16^- NKT-like cells compared to corresponding PB. Frequency of MB NKT-like cells in unexplained infertile participants was lower than fertile and URSA groups. Compared to normal participants, patients with URSA had lower frequency of PB TCRαβ⁺ and higher CD16⁺, while in infertile woman frequencies of PB CD45RO⁺, CD45RO^-, CD16^-, IL17⁺, and MB CD45RO⁺ NKT-like cells were lower. Although, PB and MB seemingly have the same histological nature, our results showed that MB contained different composition of NKT-like subsets with different cytokine profiles and could be viewed as one potential biological sample for evaluation of patients with infertility and URSA.

BOS Is Associated With Increased Cytotoxic Proinflammatory CD8 T, NKT-Like, and NK Cells in the Small Airways

BACKGROUND

Immunosuppression therapy after lung transplantation fails to prevent bronchiolitis obliterans syndrome (BOS) in many patients, primarily a disease of the small airways. We have reported that BOS is associated with a lack of suppression of cytotoxic mediators, and proinflammatory cytokines, in peripheral blood T, NKT-like (particularly CD8+) and NK cells. We also showed a loss of glucocorticoid receptor (GCR) in proinflammatory lymphocytes after transplant. It is unknown whether these proinflammatory lymphocytes target the small and/or large airways in BOS.

METHODS

Blood, bronchoalveolar lavage, large proximal, and small distal airway brushings were collected from patients with BOS (n = 10), stable lung transplant patients (n = 18), and healthy aged-matched controls (n = 10). Intracellular cytotoxic mediators (perforin/granzyme B), proinflammatory cytokines (IFNγ/TNFα), and expression of GCR were determined in lymphocytes subsets from cultured blood using flow cytometry.

RESULTS

Increases in CD8 T cells, NKT-like cells, and NK cells were found in the small distal airways in BOS compared with stable patients and controls. An increase in perforin, granzyme B, IFNγ, TNFα, and a loss of GCR from these lymphocyte subsets was also found in BOS. GCR expression by CD8+ T cells from small airways correlated with FEV1 (R = 0.834, P = 0.039). Many of these changes significantly differed from those in the large airways.

CONCLUSIONS

BOS is associated with increased cytotoxic/proinflammatory CD8+ T, NKT-like, and NK cells in the small airways. Treatments that increase GCR in these lymphocyte subsets may improve graft survival.

Genetic Modification of the Lung Directed Toward Treatment of Human Disease

Genetic modification therapy is a promising therapeutic strategy for many diseases of the lung intractable to other treatments. Lung gene therapy has been the subject of numerous preclinical animal experiments and human clinical trials, for targets including genetic diseases such as cystic fibrosis and α1-antitrypsin deficiency, complex disorders such as asthma, allergy, and lung cancer, infections such as respiratory syncytial virus (RSV) and Pseudomonas, as well as pulmonary arterial hypertension, transplant rejection, and lung injury. A variety of viral and non-viral vectors have been employed to overcome the many physical barriers to gene transfer imposed by lung anatomy and natural defenses. Beyond the treatment of lung diseases, the lung has the potential to be used as a metabolic factory for generating proteins for delivery to the circulation for treatment of systemic diseases. Although much has been learned through a myriad of experiments about the development of genetic modification of the lung, more work is still needed to improve the delivery vehicles and to overcome challenges such as entry barriers, persistent expression, specific cell targeting, and circumventing host anti-vector responses.

Steroid Resistant CD8+CD28null NKT-Like Pro-inflammatory Cytotoxic Cells in Chronic Obstructive Pulmonary Disease

Corticosteroid resistance is a major barrier to effective treatment in chronic obstructive pulmonary disease (COPD), and failure to suppress systemic inflammation in these patients may result in increased comorbidity. Although much of the research to date has focused on the role of macrophages and neutrophils involved in inflammation in the airways in COPD, recent evidence suggests that CD8⁺ T cells may be central regulators of the inflammatory network in this disease. CD8⁺ cytotoxic pro-inflammatory T cells have been shown to be increased in the peripheral blood and airways in patients with COPD, whereas smokers that have not progressed to COPD only show an increase in the lungs. Although the mechanisms underlying steroid resistance in these lymphocytes is largely unknown, new research has identified a role for cytotoxic pro-inflammatory CD8⁺ T-cells and CD8⁺ natural killer T-like (NKT-like) cells. Increased numbers of these cells and their significant loss of the co-stimulatory molecule CD28 have been shown in COPD, consistent with findings in the elderly and in clinical conditions involving chronic activation of the immune system. In COPD, these senescent cells expressed increased levels of the cytotoxic mediators, perforin and granzyme b, and the pro-inflammatory cytokines, IFNγ and TNFα. They also demonstrated increased cytotoxicity toward lung epithelial cells and importantly were resistant to immunosuppression by corticosteroids compared with their CD28⁺ counterparts. Further research has shown these cells evade the immunosuppressive effects of steroids via multiple mechanisms. This mini review will focus on cytotoxic pro-inflammatory CD8⁺CD28^null NKT-like cells involved in COPD and novel approaches to reverse steroid resistance in these cells.

Histone deacetylase 2 is decreased in peripheral blood pro-inflammatory CD8+ T and NKT-like lymphocytes following lung transplant

BACKGROUND AND OBJECTIVE

Immunosuppression therapy following lung transplantation fails to prevent chronic rejection in many patients, which is associated with lack of suppression of cytotoxic mediators and pro-inflammatory cytokines in peripheral blood T and natural killer T (NKT)-like cells. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) upregulate/downregulate pro-inflammatory gene expression, respectively; however, differences in the activity of these enzymes following lung transplant are unknown. We hypothesized decreased HDAC2 expression and increased HAT expression in pro-inflammatory lymphocytes following lung transplant.

METHODS

Blood was collected from 18 stable lung transplant patients and 10 healthy age-matched controls. Intracellular pro-inflammatory cytokines and HAT/HDAC2 expression were determined in lymphocyte subsets following culture using flow cytometry.

RESULTS

A loss of HDAC2 in cluster of differentiation (CD) 8+ T and NKT-like cells in transplant patients compared with controls was noted (CD8+ T: 28 ± 10 (45 ± 10), CD8+NKT-like: 30 ± 13 (54 ± 16) (mean ± SD transplant) (control)). Loss of HDAC2 was associated with an increased percentage of CD8+ T and NKT-like cells expressing perforin, granzyme b, interferon gamma (IFN-γ) and TNF-α (no change in HAT expression in any lymphocyte subset). There was a negative correlation between loss of HDAC2 expression by CD8+ T cells with cumulative dose of prednisolone and time post-transplant. Treatment with 10 mg/L theophylline + 1 µmol/L prednisolone or 2.5 ng/mL cyclosporine A synergistically upregulated HDAC2 and inhibited IFN-γ and TNF-α production by CD8+ T and NKT-like lymphocytes.

CONCLUSION

HDAC2 is decreased in CD8+ T and NKT-like pro-inflammatory lymphocytes following lung transplant. Treatment options that increase HDAC2 may improve graft survival.

Blood cytotoxic/inflammatory mediators in non-eosinophilic asthma

BACKGROUND

Non-eosinophilic asthma (NEA) is a distinct, often corticosteroid-resistant inflammatory asthma phenotype. NK and NKT-like cells are effector lymphocytes that we have shown, like CD28null T cells, to be relatively resistant to steroids and major sources of pro-inflammatory/cytotoxic mediators. We hypothesized that these cells and mediators would be increased in peripheral blood in NEA.

METHODS

Adults with severe asthma and variable airflow obstruction, poorly controlled despite maintenance therapy with inhaled glucocorticosteroids and long-acting bronchodilators, were recruited. Blood was assessed in those with eosinophilic asthma (n = 12), NEA (n = 25) and healthy non-smoking controls (n = 30). We applied flow cytometry to measure T, CD28null, NK and NKT-like cells and their expression of granzyme B, perforin, and killer inhibitory/activating receptors CD94(Kp43), CD158b and CD107A. Intracellular pro-inflammatory cytokine production (IFN-γ and TNF-α) was assessed in 18 controls and 10 patients with asthma/group.

RESULTS

In NEA, there was increased expression of granzyme B by CD8+ T cells vs.

CONTROLS

There was increased expression of granzyme B and CD158 and decreased CD94 on NK cells, vs. healthy controls and those with eosinophilic asthma. IFN-γ production by NK cells and TNF-α production by NKT-like cells in NEA were significantly increased vs.

CONTROLS

In both eosinophilic and NEA phenotypes, there were significant increases in CD4+28null T cells (72% and 81% increases, respectively, vs. controls) and their expression of pro-inflammatory cytokines. Significant correlations were noted between blood CD4+28null T cells and neutrophil numbers in induced sputum, and between corticosteroid dose and blood NKT-like cells, and their production of granzyme B and TNF-α and NK IFN-γ.

CONCLUSION AND CLINICAL RELEVANCE

In poorly controlled asthma, altered expression of cytotoxic/pro-inflammatory mediators can be seen on a variety of lymphocyte subsets in the peripheral blood; these changes are most apparent in NEA. Whether this pattern of expression is a marker of treatment responsiveness and future risk of exacerbations remains to be determined.

Natural killer (NK) cell profiles in blood and tumour in women with large and locally advanced breast cancer (LLABC) and their contribution to a pathological complete response (PCR) in the tumour following neoadjuvant chemotherapy (NAC): differential restoration of blood profiles by NAC and surgery

Background

NK cells contribute to tumour surveillance, inhibition of growth and dissemination by cytotoxicity, secretion of cytokines and interaction with immune cells. Their precise role in human breast cancer is unclear and the effect of therapy poorly studied. The purpose of our study was to characterise NK cells in women with large (≥3 cm) and locally advanced (T3–4, N1–2, M0) breast cancers (LLABCs) undergoing neoadjuvant chemotherapy (NAC) and surgery, and to ascertain their possible contribution to a pathological complete response (pCR).

Methods

Women with LLABCs (n = 25) and healthy female donors [HFDs (n = 10)] were studied. Pathological responses in the breast were assessed using established criteria. Blood samples were collected pre and post NAC and surgery. Flow cytometry and labelled monoclonal antibodies established absolute numbers (AbNs) and percentages (%) of NK cells, and expressing granzyme B/perforin and NKG2D. In vitro NK cytotoxicity was assessed and NK cells and cytokines (IL-2, INF-γ, TGF-β) documented in tumours using immunohistochemical techniques. Data was analysed by SPSS.

Results

Women with LLABCs had significantly reduced AbNs (160.00 ± 40.00 cells/µl) but not % of NK cells, compared with HFDs (NK: 266.78 ± 55.00 cells/µl; p = 0.020). NAC enhanced the AbN (p = 0.001) and % (p = 0.006) of NK cells in patients with good pathological responses. Granzyme B⁺/perforin⁺ cells were significantly reduced (43.41 ± 4.00%), compared with HFDs (60.26 ± 7.00%; p = 0.003). NAC increased the % in good (p = 0.006) and poor (p = 0.005) pathological responders. Pretreatment NK cytotoxicity was significantly reduced in good (37.80 ± 8.05%) and poor (22.80 ± 7.97%) responders (p = 0.001) but remained unchanged following NAC. NK-NKG2D⁺ cells were unaltered and unaffected by NAC; NKG2D expression was increased in patients with a pCR (p = 0.001). Surgery following NAC was not beneficial, except in those with a pCR. Tumour-infiltrating NK cells were infrequent but increased peritumourally (p = 0.005) showing a significant correlation (p = 0.004) between CD56⁺ cells and grade of response. Tumour cytokines had no effect.

Conclusion

Women with LLABCs have inhibited blood innate immunity, variably reversed by NAC (especially with tumour pCRs), which returned to pretreatment levels following surgery. These and in situ tumour findings suggest a role for NK cells in NAC-induced breast pCR.

Future direction of immunosuppression in lung transplantation

PURPOSE OF REVIEW

Immunosuppression regimens have helped improve rejection episodes following lung transplantation, but long-term outcomes are still not comparable with cardiac, hepatic, or renal transplantation. This review summarizes the immunobiology that contributes to rejection events and future opportunities in outcomes on the basis of providing optimized delivery of the immunosuppression based on immune-monitoring techniques, taking into account individual patient pharmacokinetics and phenotypic variance.

RECENT FINDINGS

Drug toxicities, narrow therapeutic drug monitoring windows, and current immunoassays currently do not assist in detecting the global degree of immunosuppression. The currently available randomized control trials for induction therapy or maintenance therapies do not provide additional benefits compared with previously reported retrospective trials. To push beyond the current barriers, transplant teams are focusing on the role of pharmacokinetics, assessing phenotypic variable to potentially modify to quadruple therapy and using extracorporeal photopheresis.

SUMMARY

Conventional practice for the choices of immunosuppression is being evaluated on the basis of randomized control trials as opposed to retrospective studies or single-center trials. The future direction of immunosuppression will be continued by dynamic processes taking into consideration measures to improve tolerance, reducing treatment burden, and providing the best level of evidence while accounting for rejection, infections, renal function, and other comorbidities.

Cytokine crowdsourcing: multicellular production of TH17-associated cytokines

In the 2 decades since its discovery, IL-17A has become appreciated for mounting robust, protective responses against bacterial and fungal pathogens. When improperly regulated, however, IL-17A can play a profoundly pathogenic role in perpetuating inflammation and has been linked to a wide variety of debilitating diseases. IL-17A is often present in a composite milieu that includes cytokines produced by TH17 cells (i.e., IL-17F, IL-21, IL-22, and IL-26) or associated with other T cell lineages (e.g., IFN-γ). These combinatorial effects add mechanistic complexity and more importantly, contribute differentially to disease outcome. Whereas TH17 cells are among the best-understood cell types that secrete IL-17A, they are frequently neither the earliest nor dominant producers. Indeed, non-TH17 cell sources of IL-17A can dramatically alter the course and severity of inflammatory episodes. The dissection of the temporal regulation of TH17-associated cytokines and the resulting net signaling outcomes will be critical toward understanding the increasingly intricate role of IL-17A and TH17-associated cytokines in disease, informing our therapeutic decisions. Herein, we discuss important non-TH17 cell sources of IL-17A and other TH17-associated cytokines relevant to inflammatory events in mucosal tissues.

Lung cancer is associated with decreased expression of perforin, granzyme B and interferon (IFN)-γ by infiltrating lung tissue T cells, natural killer (NK) T-like and NK cells

There is a limited understanding how of lung cancer cells evade cytotoxic attack. Previously, we have shown reduced production of the cytotoxic mediator granzyme B by CD8(+) T cells in lung cancer tissue. We hypothesized that lung cancer would be further associated with decreased production of granzyme B, perforin and proinflammatory cytokines by other cytotoxic lymphocytes, natural killer (NK) T-like and NK cells, and that this would result from soluble mediators released by the cancer cells. Lung cancer and non-cancer tissue from five patients was identified by experienced pathologists. Tumour necrosis factor (TNF)-α, interferon (IFN)-γ, granzyme B and perforin were measured in CD4 and CD8(+) T, NK T-like cells and NK cells by flow cytometry. Correlation between cancer stage and granzyme B was analysed retrospectively for 21 patients. The effects of soluble factors released by lung cancer cells on production of cytotoxic mediators and cytokines was assessed, and the role of prostaglandin E2 (PGE)2 /COX investigated using indomethacin inhibition. There were significantly decreased percentages of T, NK T-like and NK cells expressing perforin, TNF-α and IFN-γ in cancer versus non-cancer tissue, and of CD8(+) T cells and CD8(+) NK T-like cells expressing granzyme B (e.g. NK T-like cells: non-cancer 30% ± 7 versus cancer 6% ± 2·5). Cancer cells released soluble factors that inhibited granzyme B, perforin and IFN-γ production that was partially associated with the PGE2 /COX2 pathway. Thus, lung cancer is associated with decreased expression of granzyme B, perforin and IFN-γ by infiltrating T cells, NK T-like and NK cells, possibly as a result of soluble factors produced by the cancer cells including PGE2 . This may be an important immune evasion mechanism.

Modulation of lymphocyte subpopulations by extracorporeal photopheresis in patients with acute graft-versus-host disease or graft rejection

Extracorporeal photopheresis (ECP) constitutes a promising treatment for patients with steroid-refractory acute graft-versus-host disease (aGvHD) after allogeneic stem cell transplantation and for patients with graft rejection after solid organ transplantation (SOT). There is an increasing body of evidence that modulation of lymphocyte subsets might play a crucial role in the mechanism of action in ECP. We therefore analyzed immunological effects concomitantly with clinical findings in patients under ECP therapy using multicolor flow cytometry. In a patient with steroid-refractory aGvHD and a patient with progressive bronchiolitis obliterans syndrome (BOS) after double-lung transplantation, clinical responses to ECP therapy were paralleled by an increase of CD4 + CD25hiFoxP3 + regulatory T cells and a decrease of T(EMRA) (CD3 + CD8+ CD45RA+ CD62L+ effector memory T) cells as well as of natural killer (NK)T cells. In summary, immunomonitoring of T cell subsets can elucidate the mechanism of action in ECP.

Loss of glucocorticoid receptor from pro-inflammatory T cells after lung transplant

BACKGROUND

Pro-inflammatory cytokines in T and natural killer T (NKT)-like cells increase with time post-transplant in otherwise stable patients, suggesting that some patients become relatively resistant to immunosuppressants such as glucocorticoids (GC). We hypothesized that GC receptor (GCR) would be down-regulated in peripheral blood pro-inflammatory T and NKT-like cells after lung transplantation and loss of GCR would correlate with time post-transplant.

METHODS

Blood was collected from 17 stable lung transplant patients and 17 healthy, aged-matched controls. Intracellular GCR expression and pro-inflammatory cytokines were determined using flow cytometry.

RESULTS

There was a loss of GCR in CD8(+) and CD8(-) T and NKT-like cells in transplant patients compared with control subjects (transplants 37 ± 9%, controls 47 ± 12%; GCR(+)CD8(+) and CD8(-) T cells: transplants 39 ± 13%, controls 58 ± 13%). Loss of GCR was associated with a greater percentage of T cells producing interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) but not NKT-like cells. There was a correlation between the percentage of GCR-negative T cells with months post-transplant (R = 0.519, p = 0.033) and dose of prednisolone (R = 0.775, p = 0.038).

CONCLUSIONS

Time post-transplant and prednisolone dose correlate with loss of GCR in pro-inflammatory T cells in stable transplant patients, suggesting the need for reassessment of the long-term use of steroids after lung transplant in view of their attendant significant side effects.

Oxidative stress-mediated iNKT-cell activation is involved in COPD pathogenesis

Chronic obstructive pulmonary disease (COPD) is a major clinical challenge mostly due to cigarette smoke (CS) exposure. Invariant natural killer T (iNKT) cells are potent immunoregulatory cells that have a crucial role in inflammation. In the current study, we investigate the role of iNKT cells in COPD pathogenesis. The frequency of activated NKT cells was found to be increased in peripheral blood of COPD patients relative to controls. In mice chronically exposed to CS, activated iNKT cells accumulated in the lungs and strongly contributed to the pathogenesis. The detrimental role of iNKT cells was confirmed in an acute model of oxidative stress, an effect that depended on interleukin (IL)-17. CS extracts directly activated mouse and human dendritic cells (DC) and airway epithelial cells (AECs) to trigger interferonγ and/or IL-17 production by iNKT cells, an effect ablated by the anti-oxidant N-acetylcystein. In mice, this treatment abrogates iNKT-cell accumulation in the lung and abolished the development of COPD. Together, activation of iNKT cells by oxidative stress in DC and AECs participates in the development of experimental COPD, a finding that might be exploited at a therapeutic level.

NADPH oxidase mediates synergistic effects of IL-17 and TNF-α on CXCL1 expression by epithelial cells after lung ischemia-reperfusion

Ischemia-reperfusion (I/R) injury leads to increased mortality and morbidity in lung transplant patients. Lung I/R injury involves inflammation contributed by innate immune responses. IL-17 and TNF-α, from iNKT cells and alveolar macrophages, respectively, contribute importantly to lung I/R injury. This study tests the hypothesis that IL-17 and TNF-α synergistically mediate CXCL1 (a potent neutrophil chemokine) production by alveolar type II epithelial (ATII) cells via an NADPH oxidase-dependent mechanism during lung I/R. Using a hilar clamp model, wild-type and p47(phox-/-) (NADPH oxidase-deficient) mice underwent left lung I/R, with or without recombinant IL-17 and/or TNF-α treatment. Wild-type mice undergoing I/R treated with combined IL-17 and TNF-α had significantly enhanced lung dysfunction, edema, CXCL1 production, and neutrophil infiltration compared with treatment with IL-17 or TNF-α alone. However, p47(phox-/-) mice had significantly less pulmonary dysfunction, CXCL1 production, and lung injury after I/R that was not enhanced by combined IL-17-TNF-α treatment. Moreover, in an acute in vitro hypoxia-reoxygenation model, murine ATII cells showed a multifold synergistic increase in CXCL1 expression after combined IL-17-TNF-α treatment compared with treatment with either cytokine alone, which was significantly attenuated by an NADPH oxidase inhibitor. Conditioned media transfer from hypoxia-reoxygenation-exposed iNKT cells and macrophages, major sources of IL-17 and TNF-α, respectively, to ATII cells significantly enhanced CXCL1 production, which was blocked by NADPH oxidase inhibitor. These results demonstrate that IL-17 and TNF-α synergistically mediate CXCL1 production by ATII cells after I/R, via an NADPH oxidase-dependent mechanism, to induce neutrophil infiltration and lung I/R injury.

Targeting peripheral blood pro-inflammatory CD28null T cells and natural killer T-like cells by inhibiting CD137 expression: possible relevance to treatment of bronchiolitis obliterans syndrome

BACKGROUND

We have shown that bronchiolitis obliterans syndrome (BOS) is associated with attenuated suppression of pro-inflammatory cytokines and granzyme B by steroid-resistant peripheral blood CD28nullCD137+ T cells and natural killer T (NKT)-like cells. We hypothesized that we could target these steroid-resistant lymphocytes by inhibiting costimulation through CD137.

METHODS

Isolated peripheral blood mononuclear cells from transplant patients with stable lung function, patients with BOS, and healthy controls were stimulated with anti-CD3 with and without blocking anti-CD137 and with and without 10(-6) mol/liter methylprednisolone (MP) (with and without stimulatory anti-CD137). Pro-inflammatory cytokine profiles and expression of the cytotoxic mediator, granzyme B, by CD28null T and NKT-like cells were determined using flow cytometry.

RESULTS

There was a significant decrease in the percentage of CD28null T and NKT-like cells producing interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and granzyme B in all individuals in the presence of anti-CD137 blocking antibody compared with anti-CD3 alone (eg, 30% decrease in CD8+CD28null TNF-α+ cells). Stimulatory anti-CD137 was associated with an increase in pro-inflammatory/cytotoxic cells. Treatment with anti-CD137 blocking with prednisolone further reduced IFN-γ, TNF-α, and granzyme B in these cells.

CONCLUSIONS

Blocking CD137 expression in CD28null T cells and NKT-like cells is associated with down-regulation of IFN-γ, TNF-α, and granzyme B. Targeting CD137 reduces pro-inflammatory/cytotoxic expression in steroid-resistant CD28null T and NKT-like cells and may have therapeutic implications for patients with BOS.

Receptor for advanced glycation end products (RAGE) on iNKT cells mediates lung ischemia-reperfusion injury

Activation of invariant natural killer T (iNKT) cells and signaling through receptor for advanced glycation end products (RAGE) are known to independently mediate lung ischemia-reperfusion (IR) injury. This study tests the hypothesis that activation of RAGE specifically on iNKT cells via alveolar macrophage-produced high mobility group box 1 (HMGB1) is critical for the initiation of lung IR injury. A murine in vivo hilar clamp model was utilized, which demonstrated that RAGE(-/-) mice were significantly protected from IR injury. Treatment of WT mice with soluble RAGE (a decoy receptor), or anti-HMGB1 antibody, attenuated lung IR injury and inflammation, whereas treatment with recombinant HMGB1 enhanced IR injury in WT mice but not RAGE(-/-) mice. Importantly, lung dysfunction, cytokine production and neutrophil infiltration were significantly attenuated after IR in Jα18(-/-) mice reconstituted with RAGE(-/-) iNKT cells (versus WT iNKT cells). In vitro studies demonstrated that, after hypoxia-reoxygenation, alveolar macrophage-derived HMGB1 augmented IL-17 production from iNKT cells in a RAGE-dependent manner. These results suggest that HMGB1-mediated RAGE activation on iNKT cells is critical for initiation of lung IR injury and that a crosstalk between macrophages and iNKT cells via the HMGB1/RAGE axis mediates IL-17 production by iNKT cells causing neutrophil infiltration and lung IR injury.

Enhanced cytotoxic function of natural killer and natural killer T-like cells associated with decreased CD94 (Kp43) in the chronic obstructive pulmonary disease airway

BACKGROUND AND OBJECTIVE

Natural killer (NK) and natural killer T (NKT)-like cells represent a small but important proportion of effector lymphocytes that we have previously shown to be major sources of pro-inflammatory cytokines and granzymes. We hypothesized that these cells would be increased in the airway in chronic obstructive pulmonary disease (COPD), accompanied by reduced expression of the inhibitory receptor CD94 (Kp43) and increased expression of cytotoxic mediators granzyme B and perforin.

METHODS

We measured NK and NKT-like cells and their expression of CD94 in the blood of COPD patients (n = 71; 30 current and 41 ex-smokers), smokers (16) and healthy controls (25), and bronchoalveolar lavage fluid (BALF) from a cohort of subjects (19 controls, 12 smokers, 33 COPD). Activation was assessed by measuring CD69 in blood and the cytotoxic potential of NK cells by measuring granzymes A and B, and using a cytotoxicity assay in blood and BALF.

RESULTS

In blood in COPD, there were no significant changes in the proportion of NK or NKT-like cells or expression of granzyme A or NK cytotoxic potential versus controls. There was, however, increased expression of granzyme B and decreased expression of CD94 by both cell types versus controls. The proportion of NK and NKT-like cells were increased in BALF in COPD, associated with increased NK cytotoxicity, increased expression of granzyme B and decreased expression of the inhibitory receptor CD94 by both cell types.

CONCLUSIONS

Treatment strategies that target NK and NKT-like cells, their cytotoxicity and production of inflammatory mediators in the airway may improve COPD morbidity.

Up-regulation of alternate co-stimulatory molecules on proinflammatory CD28null T cells in bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is associated with lack of immunosuppression of T cell proinflammatory cytokines and increased T cell granzyme B. Repeated antigen-driven proliferation down-regulates T cell CD28. We hypothesized that down-regulation of CD28 and up-regulation of alternate co-stimulatory molecules (CD134, CD137, CD152 and CD154) on T cells may be associated with BOS. Co-stimulatory molecules, granzyme B, perforin and intracellular cytokines were measured by flow cytometry on T cells from stable lung transplant patients (n = 38), patients with BOS (n = 20) and healthy controls (n = 10). There was a significant increase in the percentage of CD4/28(null) and CD8/28(null) T cells producing granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α in BOS compared with stable patients. Down-regulation of CD28 was associated with steroid resistance and up-regulation of CD134, CD137, CD152 and CD154 on CD4(+) T cells and CD137 and CD152 on CD8(+) T cells. There was a significant correlation between increased CD28(null) /CD137 T cells producing IFN-γ, TNF-α with BOS grade (r = 0·861, P < 0·001 for CD28(null) /CD137 IFN-γ/CD8) and time post-transplant (r = 0·698, P < 0·001 for CD28(null) /CD137 IFN-γ/CD8). BOS is associated with down-regulation of CD28 and up-regulation of alternate co-stimulatory molecules on steroid-resistant peripheral blood proinflammatory CD4(+) and CD8(+) T cells. Therapeutic targeting of alternate co-stimulatory molecules on peripheral blood CD28(null) T cells and monitoring response using these assays may help in the management of patients with BOS.

IL-17A in human respiratory diseases: innate or adaptive immunity? Clinical implications

Since the discovery of IL-17 in 1995 as a T-cell cytokine, inducing IL-6 and IL-8 production by fibroblasts, and the report of a separate T-cell lineage producing IL-17(A), called Th17 cells, in 2005, the role of IL-17 has been studied in several inflammatory diseases. By inducing IL-8 production and subsequent neutrophil attraction towards the site of inflammation, IL-17A can link adaptive and innate immune responses. More specifically, its role in respiratory diseases has intensively been investigated. We here review its role in human respiratory diseases and try to unravel the question whether IL-17A only provides a link between the adaptive and innate respiratory immunity or whether this cytokine might also be locally produced by innate immune cells. We furthermore briefly discuss the possibility to reduce local IL-17A production as a treatment option for respiratory diseases.

Natural killer T cell based Immunotherapy

Natural killer T (NKT) cells play an important immunoregulatory role and are thought to bridge the innate and adaptive immune responses. Following activation through cognate interactions with lipid antigen presented in the context of CD1d molecules, NKT cells rapidly produce a plethora of cytokines and can also mediate cytotoxicity. Due to their potent effector functions, extensive research has been performed to increase our understanding on how to effectively modulate these cells. In fact, NKT cell agonists have been used as vaccine adjuvants to enhance antigen specific T and B cell responses to infections and malignancy. In this review, we will focus on recent advances in NKT cell-based vaccination strategies. Given the role that NKT cells play in autoimmune disease, infectious diseases, cancer, transplant immunology and dermatology, it is important to understand how to effectively guide their effector functions in order to develop novel immunotherapeutic strategies.