Circulating CD56dim natural killer cells and CD56+ T cells that produce interferon‐γ or interleukin‐10 are expanded in asymptomatic,E antigen‐negative patients with persistent hepatitis B virus infection

Infection with hepatitis B virus (HBV) can result in spontaneous resolution or chronic infection, which can remain asymptomatic or can progress to cirrhosis and/or hepatocellular carcinoma. The host immune response is thought to be a major determinant of the outcome of HBV infection and virus‐specific cytotoxic T lymphocytes (CTL) can mediate immunity against the virus and cause liver pathology. Antigen‐nonspecific innate lymphocytes may also contribute to HBV infection and liver disease, therefore, we examined the frequencies, phenotypes, cytolytic activities and cytokine profiles of circulating natural killer (NK) cells, CD1d‐restricted invariant natural killer T (iNKT) cells and CD56⁺ T cells in 102 asymptomatic HBV‐infected patients and compared them with those in 66 uninfected control subjects. NK cells expressing low levels of CD56 (CD56^dim) and CD56⁺ T cells were significantly expanded in the circulation of HBV‐infected patients compared with control subjects. CD1d expression and iNKT cell frequencies were similar in both groups. Despite these expansions, we did not detect augmented natural or cytokine‐induced cytotoxicity in the HBV‐infected subjects. All lymphocyte populations studied produced interferon‐γ (IFN‐γ) significantly more frequently when taken from HBV‐infected patients compared with when taken from healthy controls. Additionally, NK cells from the patients more frequently produced interleukin‐10. As our HBV‐infected cohort consisted of asymptomatic patients with low viral loads, we propose that CD56^dim NK cells and CD56⁺ T cells control HBV infection by noncytolytic mechanisms.     

Natural killer cells in highly exposed hepatitis C‐seronegative injecting drug users

Injecting drug use remains the major risk factor for hepatitis C (HCV) transmission. A minority of long‐term injecting drug users remain seronegative and aviraemic, despite prolonged exposure to HCV – termed highly exposed seronegative subjects. Natural killer (NK) cells have been implicated in this apparent protection. A longitudinal nested, three group case–control series of subjects was selected from a prospective cohort of seronegative injecting drug users who became incident cases (n = 11), remained seronegative (n = 11) or reported transient high‐risk behaviour and remained uninfected (n = 11). The groups were matched by age, sex and initial risk behaviour characteristics. Stored peripheral blood mononuclear cells were assayed in multicolour flow cytometry to enumerate natural killer cell subpopulations and to assess functional activity using Toll‐like receptor ligands before measurement of activation, cytokine production and natural cytotoxicity receptor expression. Principal components were derived to describe the detailed phenotypic characteristics of the major NK subpopulations (based on CD56 and CD16 co‐expression), before logistic regression analysis to identify associations with exposed, seronegative individuals. The CD56^dimCD16⁺ (P = 0.05, OR 6.92) and CD56^dimCD16^? (P = 0.05, OR 6.07) principal components differed between exposed, seronegative individuals and pre‐infection samples of the other two groups. These included CD56^dimCD16⁺ and CD56^dimCD16^? subsets with CD56^dimCD16⁺ IFN‐γ and TNF‐α on unstimulated cells, and CD56^dimCD16^? CD69⁺, CD107a⁺, IFN‐γ and TNF‐α following TLR stimulation. The cytotoxic CD56^dim NK subset thus distinguished highly exposed, seronegative subjects, suggesting NK cytotoxicity may contribute to protection from HCV acquisition. Further investigation of the determinants of this association and prospective assessment of protection against HCV infection are warranted.     

Differential IFN‐γ production by adult and neonatal blood CD56+ natural killer (NK) and NK‐like‐T cells in response to Trypanosoma cruzi and IL‐15

Early interferon‐gamma (IFN‐γ) release by innate cells is critical to direct type 1 immune response able to control intracellular pathogens like Trypanosoma cruzi. Although CD56^bright natural killer (NK) cells are reported to be potent early IFN‐γ producers, other CD56⁺ cells like CD56^dim NK cells and NK‐like T cells have recently been shown to also release IFN‐γ. We have here studied the contribution of each CD56⁺ lymphocyte populations in early IFN‐γ production in both adults and neonates. On this purpose, we analysed the kinetics of IFN‐γ production by RT‐PCR, ELISA and flow cytometry from 2 h onwards after T. cruzi and IL‐15 stimulation and sought for the responding CD56⁺ cells. CD56^bright and CD56^dimCD16^? NK cells were the more potent IFN‐γ early producers in response to IL‐15 and parasites in adults and neonates. In both age groups, the majority of IFN‐γ producing cells were NK cells. However, on the contrary to neonates, CD3⁺CD56⁺ NK‐like T cells and CD3⁺CD56^? ‘classical’ T cells also contributed to early IFN‐γ production in adults. Altogether, our results support that whereas NK cells responded almost similarly in neonates and adults, cord blood innate CD56⁺ and CD56^? T cells displayed major quantitative and qualitative defects that could contribute to the well‐known neonatal immune immaturity.     

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.     

Invariant natural killer T cells in chronic obstructive pulmonary disease

Background and objective: Invariant natural killer T (iNKT) cells may play an important role in regulating the innate and acquired immune systems in chronic obstructive pulmonary disease (COPD). However, there is little information regarding the potential role of iNKT cells in the pathogenesis of COPD. To investigate whether iNKT cells have an important role in COPD, the frequency of iNKT cells in peripheral blood of patients with COPD was analysed. Methods: This was a comparative study of 28 patients with COPD and 19 age‐matched healthy control subjects. Blood iNKT cells were stained with 6B11 mAb, anti‐T cell receptor Vα24 mAb, anti‐T cell receptor Vβ11 mAb or α‐galactosylceramide‐loaded CD1d‐tetramer, and analysed by flow cytometry. Results: The frequency of CD4⁺ 6B11⁺ iNKT, CD4⁺ Vα24⁺ iNKT, CD4⁺ Vβ11⁺ iNKT and CD3⁺ 6B11⁺ iNKT cells was significantly lower in peripheral blood of patients with COPD than in that of healthy control subjects. The frequency of CD4⁺ 6B11⁺ iNKT cells was significantly lower in patients with exacerbations of COPD compared with those with stable COPD. Conclusions: The frequency of iNKT was decreased in peripheral blood of patients with COPD. These results strongly suggest that iNKT cells may play an important role in the pathogenesis of COPD.     

High-dimensional mass cytometry analysis of NK cell alterations in AML identifies a subgroup with adverse clinical outcome

Natural killer (NK) cells are major antileukemic immune effectors. Leukemic blasts have a negative impact on NK cell function and promote the emergence of phenotypically and functionally impaired NK cells. In the current work, we highlight an accumulation of CD56⁻CD16⁺ unconventional NK cells in acute myeloid leukemia (AML), an aberrant subset initially described as being elevated in patients chronically infected with HIV-1. Deep phenotyping of NK cells was performed using peripheral blood from patients with newly diagnosed AML (n = 48, HEMATOBIO cohort, {"type":"clinical-trial","attrs":{"text":"NCT02320656","term_id":"NCT02320656"}}NCT02320656) and healthy subjects (n = 18) by mass cytometry. We showed evidence of a moderate to drastic accumulation of CD56⁻CD16⁺ unconventional NK cells in 27% of patients. These NK cells displayed decreased expression of NKG2A as well as the triggering receptors NKp30 and NKp46, in line with previous observations in HIV-infected patients. High-dimensional characterization of these NK cells highlighted a decreased expression of three additional major triggering receptors required for NK cell activation, NKG2D, DNAM-1, and CD96. A high proportion of CD56⁻CD16⁺ NK cells at diagnosis was associated with an adverse clinical outcome and decreased overall survival (HR = 0.13; P = 0.0002) and event-free survival (HR = 0.33; P = 0.018) and retained statistical significance in multivariate analysis. Pseudotime analysis of the NK cell compartment highlighted a disruption of the maturation process, with a bifurcation from conventional NK cells toward CD56⁻CD16⁺ NK cells. Overall, our data suggest that the accumulation of CD56⁻CD16⁺ NK cells may be the consequence of immune escape from innate immunity during AML progression.

Natural killer (NK) cells are critical cytotoxic effectors involved in leukemic blast recognition, tumor cell clearance, and maintenance of long-term remission (1). NK cells directly kill target cells without prior sensitization, enabling lysis of cells stressed by viral infections or tumor transformation. NK cells are divided into different functional subsets according to CD56 and CD16 expression (2–4). CD56^bright NK cells are the most immature NK cells found in peripheral blood. This subset is less cytotoxic than mature NK cells and secretes high amounts of chemokines and cytokines such as IFNγ and TNFα. These cytokines have a major effect on the infected or tumor target cells and play a critical role in orchestration of the adaptive immune response through dendritic cell activation. CD56^dimCD16⁺ NK cells, which account for the majority of circulating human NK cells, are the most cytotoxic NK cells. NK cell activation is finely tuned by integration of signals from inhibitory and triggering receptors, in particular, those of NKp30, NKp46 and NKp44, DNAM-1, and NKG2D (5). Upon target recognition, CD56^dimCD16⁺ NK cells release perforin and granzyme granules and mediate antibody-dependent cellular cytotoxicity through CD16 (FcɣRIII) to clear transformed cells.NK cells are a major component of the antileukemic immune response, and NK cell alterations have been associated with adverse clinical outcomes in acute myeloid leukemia (AML) (6–9). Therefore, it is crucial to better characterize AML-induced NK cell alterations in order to optimize NK cell–targeted therapies. During AML progression, NK cell functions are deeply altered, with decreased expression of NK cell–triggering receptors and reduced cytotoxic functions as well as impaired NK cell maturation (6, 9–13). Cancer-induced NK cell impairment occurs through various mechanisms of immune escape, including shedding and release of ligands for NK cell–triggering receptors; release of immunosuppressive soluble factors such as TGFβ, adenosine, PGE2, or L-kynurenine; and interference with NK cell development, among others (14).Interestingly, these mechanisms of immune evasion are also seen to some extent in chronic viral infections, notably HIV (2). In patients with HIV, NK cell functional anergy is mediated by the release of inflammatory cytokines and TGFβ, the presence of MHC^low target cells, and the shedding of ligands for NK cell–triggering receptors (2). As a consequence, some phenotypical alterations described in cancer patients are also induced by chronic HIV infections, with decreased expression of major triggering receptors such as NKp30, NKp46, and NKp44 (15, 16); decreased expression of CD16 (17); and increased expression of inhibitory receptors such as T cell immunoreceptor with Ig and ITIM domains (TIGIT) (18) all observed. In addition, patients with HIV display an accumulation of CD56⁻CD16⁺ unconventional NK cells, a highly dysfunctional NK cell subset (19, 20). Mechanisms leading to the loss of CD56 are still poorly described, and the origin of this subset of CD56⁻ NK cells is still unknown. To date, two hypotheses have been considered: CD56⁻ NK cells could be terminally differentiated cells arising from a mixed population of mature NK cells with altered characteristics or could expand from a pool of immature precursor NK cells (21). Expansion of CD56⁻CD16⁺ NK cells is mainly observed in viral noncontrollers (19, 20). Indeed, CD56 is an important adhesion molecule involved in NK cell development, motility, and pathogen recognition (22–27). CD56 is also required for the formation of the immunological synapse between NK cells and target cells, lytic functions, and cytokine production (26, 28). As a consequence, CD56⁻CD16⁺ NK cells display lower degranulation capacities and decreased expression of triggering receptors, perforin, and granzyme B, dramatically reducing their cytotoxic potential, notably against tumor target cells (2, 19, 20, 29, 30). In line with this loss of the cytotoxic functions against tumor cells, patients with concomitant Burkitt lymphoma and Epstein-Barr virus infection display a dramatic increase of CD56⁻CD16⁺ NK cells (30), which could represent an important hallmark of escape to NK cell immunosurveillance in virus-driven hematological malignancies.To our knowledge, this population has not been characterized in the context of nonvirally induced hematological malignancies. In the present work, we investigated the presence of this population of unconventional NK cells in patients with AML, its phenotypical characteristics, and the consequences of its accumulation on disease control. Finally, we explored NK cell developmental trajectories leading to the emergence of this phenotype.     

Sustained response to interferon-α plus ribavirin therapy for chronic hepatitis C is closely associated with increased dynamism of intrahepatic natural killer and natural killer T cells

Aim:  Previous studies have revealed that functional impairment of innate immune cells, including natural killer (NK) and natural killer T (NKT) cells, might be associated with the persistence of hepatitis C virus (HCV) infection. However, the involvement of innate immune cells, which predominate in the liver, in therapeutic HCV clearance is still unclear.
Methods:  To clarify the role of intrahepatic innate immune cells in the clinical outcome of patients with chronic hepatitis C (CHC) treated with interferon-α plus ribavirin (IFN/RBV), we prospectively investigated the status of NK and NKT cells in paired liver biopsy and peripheral blood (PB) samples obtained from 21 CHC patients before and immediately after IFN/RBV treatment by flow cytometry. Normal liver and PB samples were obtained from 10 healthy donors for living donor liver transplantation.
Results:  Before treatment, intrahepatic NK and NKT cells constituted a significantly lower proportion in CHC patients than in healthy individuals ( P  < 0.05). After IFN/RBV treatment, the proportions and absolute numbers of CD3^-CD161⁺ NK and CD3⁺CD56⁺ NKT cells in the liver, but not in PB, were significantly increased in sustained responders (SR) as compared with poor responders ( P  < 0.05). The proportion of CD3⁺CD161⁺ NKT cells was also increased in the liver of SR after the treatment. Moreover, there was a striking increase of activated CD152⁺ cells among CD3⁺CD56⁺ NKT cells in the liver of SR ( P  = 0.041).
Conclusion:  These findings demonstrate that sustained response to IFN/RBV treatment for patients with CHC is closely associated with increased dynamism of NK and NKT cells in the liver.     

Impaired regulation of natural killer cells in immunoglobulin synthesis by peripheral blood mononuclear cells from patients with ulcerative colitis

Immunoglobulin (Ig) synthesis, natural killer (NK) cell activity, and lymphokine production by peripheral blood mononuclear cells (PBMC) were studied in 34 patients with ulcerative colitis (UC). Levels of Ig produced by PBMC were significantly higher in patients with active UC as compared to controls. However, there were no significant differences in Ig-synthesis between patients with inactive UC and controls. NK cell activity was significantly decreased in patients with active UC as compared to controls, and a significant negative correlation was observed between the level of IgA and NK cell activity in patients with UC. Reconstitution experiments demonstrated that CD56⁺ cells from controls suppressed the levels of IgA, when added to the culture containing a constant number of B cells and CD4⁺ cells. In contrast, CD56⁺ cells from patients with active UC completely lacked the capacity to suppress IgA production. In addition, the activities of interleukin-2 and interferon-γ were significantly decreased in patients with active UC. The present study suggests that immunoregulatory abnormality of NK cells exists in patients with UC and impaired NK cell activity may be related to increased Ig-synthesis observed in these patients.     

Thymic stromal cells support differentiation of natural killer cells from CD34+ bone marrow cells in vitro

Abstract: Natural killer (NK) cells are CD3^? CD56⁺ lymphocytes characterized by exhibiting non-MHC restricted cytotoxicity. A developmental relationship between NK cells and T lymphocytes has been proposed, and, moreover, the thymus has been shown to contain NK cell precursors. In this study we utilized an in vitro assay, devised to study T-lymphocyte development from bone marrow progenitors, to investigate the ability of thymic stromal cells to support generation of NK cells from CD34⁺ bone marrow cells. CD34⁺ cells purified from healthy adults were seeded on adherent thymic stromal cells. The cells emerging after culture were phenotypically characterized by flow cytometry. We show that lymphocytes expressing the phenotypical characteristics of NK cells were generated from CD34⁺ bone marrow cells, and that these cells represented 1% of the cells recovered from the cultures. Furthermore, this was accomplished without supplement of exogenous interleukin 2 which is required for NK cell differentiation in bone marrow cultures.     

Natural killer or natural killer/T cell lineage large granular lymphocytosis associated with dasatinib therapy for Philadelphia chromosome positive leukemia

Dasatinib, a dual tyrosine kinase inhibitor, is known to modulate or suppress T-cell activation and proliferation. We report a series of 8 patients who developed chronic peripheral lymphocytosis, identified as natural killer cells or natural killer/T-cells based on their large granular lymphocyte morphologies and CD16⁺, CD56⁺, CD3⁻ or CD3⁺ immunophenotypic profiles, out of 18 patients receiving dasatinib therapy. All cases that developed large granular lymphocyte lymphocytosis achieved optimal molecular response (8/8 in large granular lymphocyte⁺ patients vs. 3/10 in large granular lymphocyte⁻ patients, p=0.002). A ⁵¹Cr release assay demonstrated that natural killer cell cytotoxicity has been enhanced in a case of large granular lymphocyte lymphocytosis compared to normal healthy donors, and that natural killer cell cytotoxicity in dasatinib-responders was superior to that in non-responders. In summary, the present study suggests that natural killer or natural killer/T cell lineage large granular lymphocyte lymphocytosis develops in association with dasatinib therapy and that large granular lymphocyte might have a therapeutic effect on Ph⁺ leukemic cells.     

A potential immunopathogenic role for reduced IL-35 expression in allergic asthma

Objective: Allergic asthma is a chronic airway inflammation resulting from an imbalance of T helper (Th) cell responses to allergens. Interleukin (IL)-35 has been shown to have potent immunoregulatory properties. Whether IL-35 participates in the immunopathogenesis of allergic asthma patients is still unknown. Methods: CD4⁺ T cells and CD4⁺CD25^? T cells were obtained from peripheral blood mononuclear cells (PBMCs) using magnetic separation. The concentration of IL-35 in plasma was measured by enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of the IL-35 subunits, EBI3 and IL-12p35, were detected by quantitative real-time PCR (qPCR). The proliferative responses of CFSE-labeled CD4⁺CD25^? T cells in the presence or absence of rhIL-35 were evaluated by flow cytometry. Cytokine production of activated CD4⁺CD25^? T cells was examined by flow cytometry and ELISA. Results: IL-35 protein and mRNA levels were decreased in allergic asthmatics. The frequencies of CD4⁺CD25⁺Foxp3⁺ Tregs and CD4⁺IL-12p35⁺ T cells in allergic asthma patients were lower than in healthy controls. Moreover, the addition of rhIL-35 suppressed CFSE⁺CD4⁺CD25^? T cell proliferation in vitro in a dose-dependent manner, and the suppression induced by rhIL-35 was associated with decreases in IL-4 but not IFN-γ and IL-17 production of activated CD4⁺CD25^? T cells. The increased level of Th1/Th2 was observed in allergic asthmatics in the presence of rhIL-35. Conclusions: Our data suggest that IL-35 can effectively suppress the proliferation and IL-4 production of activated CD4⁺CD25^? T cells in allergic asthma, and that IL-35 may be a new immunotherapy for asthma patients.     

Phenotypic analysis of nylon-wool-adherent suppressor cells that inhibit the effector process of tumor cell lysis by lymphokine-activated killer cells in patients with advanced gastric carcinoma

The causes of down-regulation of cytotoxic immune responses in cancer patients have not been fully evaluated. We previously demonstrated that T-cell-growth-factor-activated peripheral blood lymphocytes (PBL) with the surface phenotype CD8⁺ CD11b^–, from patients with widespread metastasis of gastric carcinoma, inhibited the effector process of lymphokine-activated-killer(LAK)-cell-mediated cytolysis. In this study, we examined suppressor cell activity in freshly prepared PBL from 18 patients with advanced gastric carcinoma, and 10 normal healthy individuals. The suppressor cell activity was assayed by recording whether or not PBL inhibited directly the effector process of LAK cell cytotoxicity. Most of the PBL suspensions from cancer patients showed that they contained a population of cells that can directly inhibit the effector phase of tumor cell lysis of the cytotoxic cells. To analyze further the PBL responsible for the suppression, the cells were passed over a nylon-wool column. Nylon-wool-adherent cells significantly augmented the suppression, while the cells passing through abrogated the suppressive effect. Most nylon-wool-adherent cells from 10 normal healthy controls did not inhibit the cytotoxic reaction. To determine further the suppressor-effector population in nylon-wool-adherent cells, negative-selection studies using CD8-, CD4- or CD11b-coated magnetic beads, and positive-selection studies using CD8- or CD4-coated magnetic beads were performed. Finally the results suggest that the suppressor-effector cells comprise at least two different surface phenotypes: CD8⁺ T and CD8^–CD11b⁺ cells. The possible role of CD4⁺ T cells and HLA-DR⁺ LeuM3⁺ macrophages as suppressor cells was ruled out in nylon-wood-adherent cells. CD8⁺ T and possibly CD8^–CD11b⁺ cells apparently suppressed the efferent limb of the antitumor immunity. The selective immune suppression mediated by these cells may partly be concerned with escape mechanisms of gastric carcinoma from the host immune surveillance system.Abbreviations TCGF T cell growth factor - PBL peripheral blood leucocytes - LAK lymphokine-activated killer - NK natural killer - CTL cytotoxic T lymphocytes     

The effects of stereotactic body radiotherapy on peripheral natural killer and CD3~+CD56~+ NKT-like cells in patients with hepatocellular carcinoma

Background: Both natural killer(NK) and CD3~+CD56~+ natural killer T(NKT)-like cells play critical roles in the antitumor response. This study aimed to explore the effects of stereotactic body radiotherapy(SBRT) on peripheral NK and NKT-like cells in patients with hepatocellular carcinoma(HCC), and to identify possible surface markers on these cells that correlate with the prognosis. Methods: Twenty-five HCC patients were prospectively enrolled in our study, and 10 healthy individuals were served as healthy controls. Flow cytometry was used to determine the counts and the percentages of peripheral NK and NKT-like cells, cells with certain receptors, and cells with intracellular interferon-γand TNF-α secretion at different time points, including time points of prior to SBRT, at post-SBRT, and 3-month and 6-month after treatment. The Kaplan-Meier method with the log-rank test was applied for survival analysis. Results: The peripheral NKT-like cells was increased at post-SBRT. Meanwhile, elevated levels of inhibitory receptors and reduced levels of activating receptors of NK cells were also observed in NK cells at post-SBRT, but the levels was not significantly different at 3-month and 6-month as compared with the baseline levels. Lower percentage of NKp30~+ NK cells before SBRT and higher percentage of CD158b + NK cells after SBRT were associated with poor progression-free survival. In addition, higher percentage of CD3~+CD56~+ NKT-like cells was associated with a higher overall survival rate in HCC patients. Conclusions: SBRT has an apparent effect on both peripheral NK and CD3~+ CD56~+ NKT-like cells. Lower percentage of NKp30 + NK cells before SBRT and higher percentage of CD158b + NK cells after SBRT are correlated with poor patients' PFS. Higher percentage of CD3~+ CD56~+ NKT-like cells is associated with higher OS in HCC patients.     

FEV1/FEV6 is effective as a surrogate for FEV1/FVC in the diagnosis of chronic obstructive pulmonary disease

Background and objectiveChronic Obstructive Pulmonary Disease (COPD) causes substantial morbidity and mortality across the globe. Diagnosis of COPD requires post-bronchodilator FEV1/FVC <0.70 as per GOLD Guidelines. FVC maneuver requires a minimum of 6 seconds of forceful expiration with no flow for 1 second for an accepted effort, which lacks any fixed cut-off point. This leads to discomfort, especially in advanced COPD and old aged population. We conducted this study to find the utility of FEV1/FEV6 as a surrogate for FEV1/FVC, the correlation between the two ratios, and the fixed cut-off value of FEV1/FEV6 for COPD diagnosis.MethodsThis was a prospective, cross-sectional study approved by the institutional ethics committee conducted from January 2017 to November 2018. Consented patients above 18 years suspected of COPD underwent Spirometry as per ATS guidelines. FEV1, FEV6, FEV1/FEV6 and FEV1/FVC ratios were recorded from the best acceptable maneuver.ResultsOut of 560 screened patients, 122 diagnosed as COPD. The correlation coefficient between the post-bronchodilator FEV1/FVC ratio and FEV1/FEV6 ratio was 0.972 (p < 0.01). The relationship between the post-bronchodilator FEV1/FVC ratio and FEV1/FEV6 ratio (linear regression analysis) was found out as: FEV1/FVC = ?1.845 + 1.009(FEV1/FEV6). Using this formula, the post-bronchodilator FEV1/FEV6 value of 71.845 was obtained corresponding to the post-bronchodilator FEV1/FVC value of 70.00.ConclusionWe found a positive correlation coefficient (r = 0.972, p < 0.001) between the FEV1/FEV6 and FEV1/FVC ratios and the cut off value of 71.845 (p < 0.01) for the post-bronchodilator FEV1/FEV6 ratio for the diagnosis of COPD. Thus FEV1/FEV6 should be used as a surrogate for FEV1/FVC for the diagnosis of COPD.     

Increased CD4+CD16+ and CD4+CD56+ T cell subsets in Behçet's disease

Behçet's disease is a systemic vasculitis of unknown etiology. Various immune abnormalities have previously been shown in Behçet's disease. We investigated T lymphocyte subsets associated with cytotoxic activity and natural killer (NK) cells by flow cytometry in 37 patients with Behçet's disease, 38 healthy controls, and 17 diseased control patients. Compared to the healthy controls, CD4⁺CD16⁺ and CD4⁺CD56⁺ subsets were found to be higher in the Behçet's disease group as well as in the disease control group (CD4⁺CD16⁺: BD=5?±?3, DC=14?±?14, HC= 3?±?2, P=0.001; CD4⁺CD56⁺: BD=11?±?5, DC= 18?±?17, HC=8?±?6, P=0.01). CD8⁺CD16⁺ and CD8⁺CD56⁺ T cell subsets were at normal levels in Behçet's disease but found to be elevated in disease controls. Similarly, NK cells (CD16⁺CD56⁺) were high only in the disease control group. Significant increases in CD4⁺CD16⁺ and CD4⁺CD56⁺ cell subsets in Behçet's patients and disease controls suggest that T cell activation patterns of these subsets in Behçet's disease are similar to those in other inflammatory disorders.     

CD56+ NK lymphomas:clinicopathological features and prognosis

The surface molecule CD56 marks a category of malignant lymphoma of putative natural killer (NK) cell origin. We conducted a retrospective analysis of 24 cases of CD56⁺ NK lymphoma/leukaemia to define the clinicopathologic and prognostic features of this specific group of lymphomas. 56 cases of nasal lymphomas and 204 cases with an initial diagnosis of peripheral T-cell lymphoma were retrospectively analysed. To specifically examine lymphomas of putative NK origin, only those that were negative for surface expression of CD3 but positive for CD56 were analysed. 24 cases were identified. The initial predominant sites of involvement were nasal (n =18), palate (n = 1), nodal (n = 1) and multi-organ (n =4). Clinically, in patients with disease localized to one anatomical site (n = 20), most had symptoms confined to the nose, with a high percentage in early stage (I: 91%; IV: 9%). The marrow was not involved in any of these cases. However, patients with multi-organ involvement at presentation (n = 4) behaved differently. All presented acutely with pancytopenia, hepatosplenomegaly, and marrow infiltration with haemophagocytosis. A leukaemic phase was observed in one case. Anthracycline containing combination chemotherapy resulted in complete remission in 75% of patients with localized disease, but only in 25% with multi-organ involvement. The median survival of patients with localized disease was 12 months, compared with 2 months in the multi-organ group (P =0.06); the disease-free survival was significantly better in the former (P <0.01). The overall median survival of all patients was still poor at 11 months. We conclude that CD56⁺ NK lymphomas could be divided into two main patterns of disease presentations: localized (predominantly nasal), and multi-organ involvement. Each has different clinicopathologic and prognostic features. Conventional chemotherapy appeared ineffective for the majority of patients, and innovative treatment modalities are needed to improve outcome.     

iNKT cells are increased in children with severe therapy-resistant asthma

Background

Invariant natural killer T (iNKT) cells play complex functions in the immune system, releasing both Th1 and Th2 cytokines. The role of iNKT cells in human asthma is still controversial and never described in severe therapy-resistant asthma in children. The objective of this work was to analyse iNKT frequency in peripheral blood of children with severe therapy-resistant asthma (STRA), compared to children with milder asthma and healthy controls.

The Impact of Heart Failure on the Classification of COPD Severity

BackgroundPulmonary restriction—a reduction of lung volumes—is common in heart failure (HF), rendering severity grading of chronic obstructive pulmonary disease (COPD) potentially problematic in subjects with both diseases. We compared pulmonary function in patients with either HF or COPD, or the combination to assess whether grading of COPD using the Global Initiative of Chronic Obstructive Lung Disease classification is hampered in the presence of HF.Methods and ResultsIn 2 cohorts involving 591 patients with established HF and 405 with a primary care diagnosis of COPD, the presence of HF and COPD was assessed according to guidelines. HF severity was staged according to the NYHA classification system into Classes I–IV. COPD was diagnosed if the ratio of post-bronchodilator forced expiratory volume in 1 second and forced vital capacity (FEV1/FVC) was <0.70, and categorized in GOLD stages I–IV according to post-bronchodilator–predicted FEV1 levels (FEV1% ≥80%; 50–79%; 30–49%; <30%). In total, 557 patients with HF only, 108 with HF+COPD, and 194 with COPD only were studied. Patients, who had neither HF nor COPD according to definition, or HF with reversible obstruction in post-bronchodilator pulmonary function tests were excluded from this analysis (n = 137). Compared with COPD only, patients with HF plus COPD had higher levels of post-bronchodilator FEV1/FVC (median [quartiles] 0.57 [0.47–0.64] vs 0.62 [0.55–0.66] and lower total lung capacity % (115 [104–126]% vs 105 [95–117]%, P < .001) P < .001), but comparable levels of post-bronchodilator FEV1% (70 [56–84]% vs 68 [54–80]%, P = .22) and thus similar distributions of GOLD stages I–IV in both groups (24/56/19/4% vs 31/50/19/1%, P = .57). In patients with HF only, 25% exhibited pre-bronchodilator FEV1% levels of <80% (FEV1% 94 [80–108]%), despite a pre-bronchodilator FEV/FVC ratio ≥0.7 in this group. The reduction of FEV1 in patients with HF only was associated with HF severity.ConclusionsIn stable HF, FEV1 may be significantly reduced even in the absence of “real” airflow obstruction. In this situation, diagnosing COPD according to GOLD criteria (based on FEV1/FVC) still seems feasible, because both FEV1 and FVC are usually decreased to an equal extent in HF. However, classifying COPD based on FEV1 levels may overrate obstruction severity in patients with combined disease (HF plus COPD), and thus may lead to unjustified use of bronchodilators.     

Human acute myeloid leukemia CD34+CD38? stem cells are susceptible to allorecognition and lysis by single KIR-expressing natural killer cells

The concept of tumor immunosurveillance has raised prospects for natural killer cell-based immunotherapy of human cancer. The cure of acute myeloid leukemia may depend on eradication of leukemic stem cells, the self-renewing component of leukemia. Whether natural killer cells can recognize and lyse leukemic stem cells is not known. To develop strategies that effectively target acute myeloid leukemia-leukemic stem cells, we investigated anti-leukemic effects of human alloreactive single KIR⁺ natural killer cells. Natural killer effectors with KIR specificity mismatched with respect to HLA class I allotype of target cells effectively recognized acute myeloid leukemia-leukemic stem cells defined phenotypically as CD34⁺CD38⁻, while healthy bone marrow-derived CD34⁺CD38⁻ hematopoietic stem cells were spared, as demonstrated by cytotoxicity and hematopoietic colony-forming assays. The HDAC inhibitor valproic acid increased the activating NKG2D ligand-dependent lysis of acute myeloid leukemia-CD34⁺CD38⁻ leukemic stem cells. These results show that alloreactive natural killer cells have the potential to detect and target leukemic stem cells, and thus to improve the treatment outcome in acute myeloid leukemia.