CD28null T-cells Research Articles

Consideration of T-Cell Profile in the Examination of Statin Efficacy in Inflammatory Diseases, Neurodegeneration, and Neurocognitive Performance.

Statins are a cornerstone in the medical management of cardiovascular disease, yet their efficacy varies greatly between individuals. In this commentary, we outline the evidence for the role of CD4+CD28null T-cell expansion as a critical moderator of the effects of statins in preventing cardiovascular events via the reduction of pathological inflammation. Given this relationship, we argue that T-cell profiles should be considered as a patient characteristic in clinical and preclinical studies examining statin efficacy in other age- and inflammation-related pathologies. We discuss the implications this may have for studies of statin use in numerous disease processes-notably, dementia and neurocognitive dysfunction-and the potential for T-cell profiles to be used as a prognosticator for statin efficacy in rheumatoid arthritis, Alzheimer's disease, and multiple sclerosis.

#1186 Novel T-cell subsets as early non-invasive biomarkers of vascular damage in chronic kidney disease progression

Abstract Background and Aims The exploration of early biomarkers for diagnosing vascular alterations in CKD-MBD holds significant clinical potential. Previous evidence has demonstrated profound alterations in immune cell populations linked to vascular homeostasis in CKD dialysis patients. This study aimed to evaluate the utility of immune cell populations as early and progressive biomarkers for non-dialysis CKD patients, examining their correlation with vascular damage. Method A total of 43 non-dialysis CKD patients and 38 sex- and age-matched controls were included in the study. Patients were categorized into four groups based on their estimated glomerular filtration rate (eGFR): CKD-2/3a, CKD-3b, CKD-4, and CKD-5. The assessment of left carotid adventitial neovascularization and intima-media thickness (cIMT) was conducted using ultrasensitive ultrasonography without contrast, specifically employing Superb Microvascular Image (SMI) technology. Pulse wave velocity (PWV) was measured to determine aortic stiffness, utilizing the Complior Analyzer. Immunosescencent T-cells (CD4+CD28null), angiogenic T-cells (Tang) (CD3+CD31+CD184+) and their subsets (CD4+Tang, CD8+Tang and CD28nullTang) were quantified by flow cytometry in Peripheral Blood Mononuclear Cells. Results No significant differences in age and body mass index were observed between the control group and the four CKD stages. Notably, the values of estimated glomerular filtration rate (eGFR) exhibited a significant and progressive decrease, as indicated in the Table 1. Biochemical parameters related to CKD-MBD are also detailed in the same table. The carotid intima-media thickness (cIMT) was found to be significantly higher in CKD-5 compared to CKD 2-3a (CKD 2-3a = 0.66 ± 0.14 mm, CKD-5 = 0.80 ± 0.12 mm, p = 0.03). In patients at stage 4 of CKD, there was an increased number of adventitial vasa vasorum (control = 0.53 ± 1.33, CKD-4 = 1.67 ± 2.04, p = 0.0009) and a greater area of adventitial neovascularization in the carotid artery compared to the control group (control = 0.51 ± 1.31%, CKD-4 = 2.67 ± 2.27%, p = 0.0003). PWV was significantly higher in CKD-5 (control = 10.81 ± 2.01 m/s, CKD-5 = 12.91 ± 3.70 m/s, p = 0.045). Additionally, a significant correlation was observed between PWV and both the number of adventitial vasa vasorum at the carotid artery (r = 0.24, p = 0.028) and the area of adventitial neovascularization (r = 0.34, p = 0.002). CD4+CD28null T-cells were increased in CKD patients compared to control group (control = 24.99[5.52], CKD = 27.35[8.58], p = 0.004). Although no differences were found in total levels of Tang in CKD patients (control = 1.64 ± 0.89, CKD= 1.5 ± 1.02, p = 0.757), a strong negative correlation was observed across CKD stages (trend analysis for stages: r = −0.361, p = 0.017). Moreover, CKD patients had altered CD8+ and CD4+ Tang frequencies (CD4+Tang: control = 39.52[18.46], CKD = 33.60[12.84], p = 0.054; CD8+Tang: control = 40.03[14.38], CKD = 48.25[13.16], p = 0.012) and Tang CD28null were increased in CKD patients (control = 44.14[11.99], CKD = 48.62[12.08], p = 0.004). Finally, Tang frequency was significantly correlated with the number of adventitial vasa vasorum (r = 0.368, p = 0.032), area of adventitial neovascularization (r = −0.401, p = 0.019), PWV (r = −0.341, p = 0.048) and cIMT (r = −0.364, p = 0.034). Conclusion Carotid adventitial neovascularization, cIMT and PWV demonstrated an increase in advanced CKD stages, implying that they may possess limited clinical utility as early markers of vascular damage in the initial stages of CKD. Immunosenescence and vascular damage traits were found across the CKD spectrum. Altered Tang frequency may be considered a progressive biomarker of impaired vascular homeostasis in CKD.

CMV Infection Is Directly Related to the Inflammatory Status in Chronic Heart Failure Patients.

High levels of inflammation play an important role in chronic heart failure (CHF). Patients with CHF have elevated levels of pro-inflammatory cytokines circulating systemically, mainly TNF and IL-6. However, there are almost no studies that relate these levels to the functional status of patients in CHF, much less to their CMV serostatus. In this study, patients with CHF (n=40; age=54.9 ± 6.3; New York Heart Association functional classification (NYHA, I-III) and healthy controls (n=40; age=53.5 ± 7.1) were analyzed. The serum concentrations of nine pro- and anti-inflammatory cytokines were measured by Luminex® xMap Technology and the basal level of mRNA expression of some immune molecules was quantified by TaqMan™ Array in CD4+ T-lymphocytes. The concentration of these cytokines in culture supernatants in response to anti-CD3 and LPS was also measured. The percentage of CD28null T-cells was determined, as well as the antibody titer against CMV. We found a higher concentration of all cytokines studied in CHF serum compared to healthy controls, as well as a direct correlation between functional status in CHF patients and levels of inflammatory cytokines. Moreover, the highest cytokine concentrations were found in patients with higher concentrations of lymphocytes lacking CD28 molecule. The cytokine production was much higher in CMV+ patients, and the production of these cytokines was found mainly in the T-lymphocytes of CMV+ patients in response to anti-CD3. Anti-CMV antibody levels were positively correlated with cytokine levels. The baseline expression of specific mRNA of the main molecules involved in the Th1 response, as well as molecules related to the CD4+CD28 null subset was higher in CMV+ patients. The cytokine concentrations are higher in CHF CMV+ patients and these concentrations are related to the production of antibodies against CMV. These high levels of cytokines are also associated with the more differentiated CD28null lymphocyte populations. All this, together with the dynamics of the pathology itself, makes CMV+ patients present a worse functional status and possibly a worse evolution of the pathology.

Expansion of CD10neg neutrophils and CD14+HLA-DRneg/low monocytes driving proinflammatory responses in patients with acute myocardial infarction.

Immature neutrophils and HLA-DRneg/low monocytes expand in cancer, autoimmune diseases and viral infections, but their appearance and immunoregulatory effects on T-cells after acute myocardial infarction (AMI) remain underexplored. We found an expansion of circulating immature CD16+CD66b+CD10neg neutrophils and CD14+HLA-DRneg/low monocytes in AMI patients, correlating with cardiac damage, function and levels of immune-inflammation markers. Immature CD10neg neutrophils expressed high amounts of MMP-9 and S100A9, and displayed resistance to apoptosis. Moreover, we found that increased frequency of CD10neg neutrophils and elevated circulating IFN-γ levels were linked, mainly in patients with expanded CD4+CD28null T-cells. Notably, the expansion of circulating CD4+CD28null T-cells was associated with cytomegalovirus (CMV) seropositivity. Using bioinformatic tools, we identified a tight relationship among the peripheral expansion of immature CD10neg neutrophils, CMV IgG titers, and circulating levels of IFN-γ and IL-12 in patients with AMI. At a mechanistic level, CD10neg neutrophils enhanced IFN-γ production by CD4+ T-cells through a contact-independent mechanism involving IL-12. In vitro experiments also highlighted that HLA-DRneg/low monocytes do not suppress T-cell proliferation but secrete high levels of pro-inflammatory cytokines after differentiation to macrophages and IFN-γ stimulation. Lastly, using a mouse model of AMI, we showed that immature neutrophils (CD11bposLy6GposCD101neg cells) are recruited to the injured myocardium and migrate to mediastinal lymph nodes shortly after reperfusion. In conclusion, immunoregulatory functions of CD10neg neutrophils play a dynamic role in mechanisms linking myeloid cell compartment dysregulation, Th1-type immune responses and inflammation after AMI.

Cytomegalovirus infection is associated with an increase in aortic stiffness in older men which may be mediated in part by CD4 memory T-cells.

Human Cytomegalovirus (CMV) infection is associated with atherosclerosis, higher cardiovascular disease (CVD) risk, and an increase in memory T-cells (Tmem). T-cells have also been implicated in CVD, independently of CMV infection. To better understand the CMV-associated CVD risk, we examined the association between CMV (IgG) serostatus and central aortic (carotid-to-femoral) pulse wave velocity (cfPWV), an early, independent predictor of CVD. We also investigated if such an association might be reflected by the distribution of Tmem and/or other T-cell subsets.Methods: Healthy older volunteers (60-93 years) underwent routine clinical and laboratory evaluation, including assessment of cfPWV in eligible participants. Flow-cytometry was used to assess proportions of memory T-cells, CD28null T-cells, and CMV-specific T-cells. The following associations were examined; CMV serostatus/cfPWV, CMV serostatus/proportion of Tmem, proportion of Tmem/cfPWV, CD28null T-cells/cfPWV, and CMV-specific T-cells/cfPWV. Linear regression models were used to adjust for age, sex, socioeconomic status, smoking, waist-to-hip ratio, cholesterol, and blood pressure as required.Results: Statistically significant positive associations were found (P-values for the fully adjusted models are given); CMV serostatus/cfPWV in men (P ≤ 0.01) but not in women, CMV serostatus/proportions of CD4 Tmem in men (P ≤ 0.05) but not in women; proportions of CD4 Tmem/cfPWV among CMV seropositive (CMV+) people (P ≤ 0.05) but not CMV seronegative (CMV-) people.Conclusion: CMV infection increases the CVD risk of older men by increasing cfPWV. This may be mediated in part by increased proportions of CD4 Tmem, higher numbers of which are found in CMV+ older people and more so among men than women. Given the high prevalence of CMV worldwide, our findings point to a significant global health issue. Novel strategies to mitigate the increased CVD risk associated with CMV may be required.

Adaptive Immune Responses in Human Atherosclerosis.

Atherosclerosis is a chronic inflammatory disease that is initiated by the deposition and accumulation of low-density lipoproteins in the artery wall. In this review, we will discuss the role of T- and B-cells in human plaques at different stages of atherosclerosis and the utility of profiling circulating immune cells to monitor atherosclerosis progression. Evidence supports a proatherogenic role for intraplaque T helper type 1 (Th1) cells, CD4+CD28null T-cells, and natural killer T-cells, whereas Th2 cells and regulatory T-cells (Treg) have an atheroprotective role. Several studies indicate that intraplaque T-cells are activated upon recognition of endogenous antigens including heat shock protein 60 and oxidized low-density lipoprotein, but antigens derived from pathogens can also trigger T-cell proliferation and cytokine production. Future studies are needed to assess whether circulating cellular biomarkers can improve identification of vulnerable lesions so that effective intervention can be implemented before clinical manifestations are apparent.

Atherosclerosis in rheumatoid arthritis: associations between anti-cytomegalovirus IgG antibodies, CD4+CD28null T-cells, CD8+CD28null T-cells and intima-media thickness

Patients with rheumatoid arthritis (RA) have an accelerated progression of atherosclerosis. The aims of this study were to study the associations between subsets of T-cells, subclinical atherosclerosis assessed by intima-media thickness (IMT) and serological status for CMV in patients with RA. Patients with new-onset RA (n=79), aged ≤60 years at diagnosis, were included in a prospective study of atherosclerosis. Controls matched for age and sex were also included (n=44). Ultrasound measurement of IMT in the common carotid artery was undertaken at inclusion (T0), after 1.5 years (T1.5) and after 11 years (T11). At T11, flow-cytometry analysis was undertaken to investigate subsets of T-cells. Serological analysis for CMV was undertaken from samples collected at T0. At T0, 66% of the patients and controls were CMV immunoglobulin G-positive. CMV-IgG positive patients had a significantly more rapid increase in IMT at T1.5, compared with controls and CMV-IgG negative patients. CMV-IgG positive patients had a significantly higher percentage of T-cells lacking CD28 (both CD4+CD28null and CD8+CD28null T-cells) than CMV-IgG negative patients. Increased levels of CD4+CD28null and CD8+CD28null T-cells were significantly associated with IMT at T11, adjusted for systolic blood pressure. CX3CR1 was expressed in CD4+ and CD8+ CD28null T-cells, but CX3CR1 per se was not associated with increased IMT. Presence of CMV IgG-antibodies in patients with RA is associated with altered T-cell-populations and an increased burden of atherosclerosis. A possible protective effect of antiviral treatment in CMV-positive patients with new-onset RA should be considered.

Interleukin-7 and interleukin-15 drive CD4+CD28null T lymphocyte expansion and function in patients with acute coronary syndrome.

AimsInflammation has important roles in atherosclerosis. CD4+CD28null (CD28null) T cells are a specialized T lymphocyte subset that produce inflammatory cytokines and cytotoxic molecules. CD28null T cells expand preferentially in patients with acute coronary syndrome (ACS) rather than stable angina and are barely detectable in healthy subjects. Importantly, ACS patients with CD28null T-cell expansion have increased risk for recurrent acute coronary events and poor prognosis, compared to ACS patients in whom this cell subset does not expand. The mechanisms regulating CD28null T-cell expansion in ACS remain elusive. We therefore investigated the role of cytokines in CD28null T-cell expansion in ACS.Methods and resultsHigh-purity sorted CD4+ T cells from ACS patients were treated with a panel of cytokines (TNF-α, IL-1β, IL-6, IL-7, and IL-15), and effects on the number, phenotype, and function of CD28null T cells were analysed and compared to the control counterpart CD28+ T-cell subset. IL-7- and IL-15-induced expansion of CD28null T cells from ACS patients, while inflammatory cytokines TNF-α, IL-1β, and IL-6 did not. The mechanisms underlying CD28null T-cell expansion by IL-7/IL-15 were preferential activation and proliferation of CD28null T cells compared to control CD28+ T cells. Additionally, IL-7/IL-15 markedly augmented CD28null T-cell cytotoxic function and interferon-γ production. Further mechanistic analyses revealed differences in baseline expression of component chains of IL-7/IL-15 receptors (CD127 and CD122) and increased baseline STAT5 phosphorylation in CD28null T cells from ACS patients compared to the control CD28+ T-cell subset. Notably, we demonstrate that CD28null T-cell expansion was significantly inhibited by Tofacitinib, a selective JAK1/JAK3 inhibitor that blocks IL-7/IL-15 signalling.ConclusionOur novel data show that IL-7 and IL-15 drive the expansion and function of CD28null T cells from ACS patients suggesting that IL-7/IL-15 blockade may prevent expansion of these cells and improve patient outcomes.

Effect of statins on atherosclerosis in chronic kidney disease patients guided by CD4+CD28nullT cells over duration of six months

Abstract Objectives Chronic kidney disease and atherosclerosis are considered to be inflammatory process in which T cells and cytokines participate. This study determines the effect of statin therapy as an anti-inflammatory agent on the level of CD4+CD28null T lymphocyte population, and subsequently on atherosclerosis in patients with chronic renal disease. Methods We recruited 90 chronic kidney disease patients. The patients were divided into three groups according to carotid intimal medial thickness (CIMT) as an indicator of atherosclerosis. Two groups (group A in whom CIMT above 0.95 mm and B in whom CIMT below 0.95 mm) were given statin (atorvastatin 20mg) while the third group (group C in whom CIMT below 0.95 mm) continue only on the conservative treatment for CKD patients. CD4+CD28null T cells was measured in the three groups at the beginning of the study and after 6 months of statin therapy. Results CD4+CD28null T cells was decreased in statin groups (group A and B) when compared to no-statin group (group C) at the end of the study. Multivariable regression analysis for the effect of statin therapy showed that statin can independently increase the percentage of decrease both CD4+CD28null cells at the end of our study (p-value <0.0001). Conclusion Our study demonstrates that statins reduce CD4+CD28null T cells in CKD patients especially with atherosclerosis suggesting that statins may help in altering the inflammatory process that lead to atherosclerosis.

Low Levels of CD4+CD28null T Cells at Baseline Are Associated With First-Time Coronary Events in a Prospective Population-Based Case-Control Cohort.

CD4+CD28null T cells have been shown to be associated with recurrent coronary events and suggested as potential biomarker and therapeutic target. It is unknown whether CD4+CD28null T cells associate with first-time cardiovascular events. We examined CD4+CD28null T cells in a prospective population-based cohort and in patients with advanced atherosclerosis. Approach and Results: CD4+CD28null T cells were quantified in 272 individuals experiencing a first-time coronary event during up to 17 years of follow-up and 272 age- and sex-matched controls in a case-control study, nested within the population-based Malmö Diet and Cancer study. The highest tertile of CD4+CD28null T cells was associated with a lower incidence of first-time coronary events compared with the lowest tertile (odds ratio, 0.48 [95% CI, 0.29-0.79], P=0.004) when adjusting for Framingham risk factors. This association remained significant for events recorded after >9 years of follow-up, when most coronary events occurred, but not during the first 9 years of follow-up, despite similar odds ratio. Additionally, we analyzed CD4+CD28null T cells in 201 patients with advanced atherosclerosis undergoing carotid endarterectomy. The adjusted hazard ratio for cardiovascular events in patients with advanced atherosclerosis was 2.11 (95% CI, 1.10-4.05, P=0.024), comparing the highest with the lowest CD4+CD28null T-cell tertile. Our findings reveal complex associations between CD4+CD28null T cells and cardiovascular disease. Although we confirm the reported positive associations with an adverse prognosis in patients with already established disease, the opposite associations with first-time coronary events in the population-based cohort may limit the clinical use of CD4+CD28null T cells.

Expanded peripheral CD4+CD28null T cells and its association with atherosclerotic changes in patients with end stage renal disease on hemodialysis

End-stage renal disease (ESRD) patients, including those on hemodialysis, possess a high risk for cardiovascular diseases, as the first leading cause of death among them. Traditional risk factors do not utterly elucidate this. Throughout the last two decades, CD4+CD28null T cells; an unusual subset of T lymphocytes, was detected high with excess cardiovascular (CV) mortality. We aimed to investigate the circulating CD4+CD28null T cells frequency in ESRD patients on hemodialysis and to evaluate their relationship with atherosclerotic changes. High-resolution carotid ultrasonography was done to assess the common carotid artery intima media thickness in a number of ESRD patients, accordingly patients were selected and subdivided into two groups; 30 with atherosclerosis (mean [SD] age, 51.6 [6.3] years) and 30 without (mean [SD] age, 48.9 [5.5] years). Another 30 healthy individuals (mean [SD] age, 48.5 [6.8] years) were enrolled. Analysis of CD4+CD28null T-cells frequency by flow-cytometry was performed in all studied subjects. CD4+CD28null T cell percentage was significantly higher in ESRD patients, (mean [SD], 7.3 [2.7] %) compared to healthy individuals (mean [SD], 3.0 [0.8] %), (p < 0.001). Additionally, the expansion of these unusual T lymphocytes was significantly higher in ESRD patients with atherosclerotic changes (mean [SD], 9.47 [0.75] %) compared to those without atherosclerosis (mean [SD], 5.22 [2.14] %), (p < 0.001). In conclusion circulating CD4+CD28null T lymphocyte population showed expansion in ESRD patients, and of interest in correlation to preclinical atherosclerotic changes.

Senescent T Cells Predict the Development of Hyperglycemia in Humans.

Senescent T cells have been implicated in chronic inflammatory and cardiovascular diseases. In this study, we explored the relationship between senescent T cells and glycemic status in a cohort of 805 participants by investigating the frequency of CD57+ or CD28null senescent T cells in peripheral blood. Participants with normal glucose tolerance (NGT) with follow-up data (N = 149) were included to determine whether hyperglycemia (prediabetes or type 2 diabetes) developed during follow-up (mean 2.3 years). CD8+CD57+ and CD8+CD28null T-cell frequencies were significantly higher in prediabetes and type 2 diabetes compared with NGT. Increased CD57+ or CD28null cells in the CD8+ T-cell subset were independently associated with hyperglycemia. Furthermore, among participants with baseline NGT, the frequency of CD8+CD57+ T cells was an independent predictor of hyperglycemia development. Immunofluorescent analyses confirmed that CD8+CD57+ T-cell infiltration was increased in visceral adipose tissue of patients with prediabetes or type 2 diabetes compared with those with NGT. Our data suggest that increased frequency of senescent CD8+ T cells in the peripheral blood is associated with development of hyperglycemia.

Correlation between CD4+CD28null T lymphocytes, regulatory T cells and plaque rupture: An Optical Coherence Tomography study in Acute Coronary Syndromes

BackgroundA sizeable proportion of patients with Acute Coronary Syndromes (ACS) shows a unique adaptive immune system profile, associated to a worse outcome, characterized by higher CD4+CD28null T-cells, lower regulatory T-cells (Treg) and increased CD4+CD28null/Treg ratio. We sought to investigate the correlation between CD4+CD28null T-cells, Treg, CD4+CD28null/Treg ratio and plaque phenotype as assessed by Optical Coherence Tomography (OCT). MethodsPeripheral blood mononuclear cells (PBMC) were collected from 30 Non-ST Elevation Myocardial Infarction (NSTEMI) patients, sub-grouped according to OCT analysis of culprit lesions into two cohorts: Ruptured Fibrous Cap (NSTEMI-RFC, n = 12) and Intact Fibrous Cap (NSTEMI-IFC, n = 18). Stable Angina patients (SA, n = 18) were used as controls. We examined the frequency of CD4+CD28null and Treg (defined as CD4+CD25highCD127lowFoxp3+ T-cells) by flow-cytometry. ResultsCD4+CD28null frequency (median, range) was significantly higher in NSTEMI-RFC patients (17.3%, 12.5–33.8) as compared with NSTEMI-IFC (3.8%, 0.3–14.1) and SA (3%, 0.6–17.7) (P < 0.001 for all comparisons). We also found a higher CD4+CD28null/Treg ratio in NSTEMI-RFC patients (6.6%, 3.7–13.9) than in NSTEMI-IFC (1.6%, 0.3–5.2) and SA (1.2%, 0.3–8.7) (P < 0.001 for all comparisons). Finally, there was an inverse correlation between CD4+CD28null/Treg ratio and cap-thickness (R = −0.44; P = 0.002). ConclusionPatients with NSTEMI presenting with RFC as culprit lesion at OCT evaluation have a specific perturbation of adaptive immunity, mostly involving CD4+CD28null T- cells and Tregs, as compared with patients with IFC and SA. This specific imbalance of T-cells might play a key role in fibrous cap thinning, predisposing atherosclerotic plaque to rupture.

The host cellular immune response to cytomegalovirus targets the endothelium and is associated with increased arterial stiffness in ANCA-associated vasculitis

BackgroundCardiovascular disease is a leading cause of death in ANCA-associated vasculitis (AAV). An expansion of CD4+CD28null T cells is seen mainly in cytomegalovirus (CMV)-seropositive individuals and has been linked to increased cardiovascular disease risk in other conditions. The aims of this study were to phenotype CD4+CD28null T cells in AAV with respect to their pro-inflammatory capacity and ability to target and damage the endothelium and to investigate their relationship to arterial stiffness, a marker of cardiovascular mortality.MethodsCD4+CD28null T cells were phenotyped in 53 CMV-seropositive AAV patients in stable remission and 30 age-matched CMV-seropositive healthy volunteers by flow cytometry following stimulation with CMV lysate. The expression of endothelial homing markers and cytotoxic molecules was evaluated in unstimulated CD4+CD28null T cells. Arterial stiffness was measured by carotid-to-femoral pulse wave velocity (PWV) in patients with AAV.ResultsCD4+CD28null T cells were CMV-specific and expressed a T helper 1 (Th1) phenotype with high levels of interferon-gamma (IFN-γ) and tumour necrosis factor-alpha (TNF-α) secretion. They also co-expressed the endothelial homing markers CX3CR1, CD49d and CD11b and cytotoxic molecules perforin and granzyme B. CD4+CD28null T cells were phenotypically similar in patients with AAV and healthy volunteers but their proportion was almost twice as high in patients with AAV (11.3% [3.7–19.7] versus 6.7 [2.4–8.8]; P = 0.022). The size of the CD4+CD28null T-cell subset was independently linked to increased PWV in AAV (0.66 m/s increase per 10% increase in CD4+CD28null cells, 95% confidence interval 0.13–1.19; P = 0.016).ConclusionThe host cellular immune response to CMV leads to the expansion of cytotoxic CD4+CD28null T cells that express endothelial homing markers and are independently linked to increased arterial stiffness, a marker of cardiovascular mortality. Suppression of CMV in AAV may be of therapeutic value in reducing the risk of cardiovascular disease.

CD28null pro-atherogenic CD4 T-cells explain the link between CMV infection and an increased risk of cardiovascular death.

An increased risk of cardiovascular death in Cytomegalovirus (CMV)-infected individuals remains unexplained, although it might partly result from the fact that CMV infection is closely associated with the accumulation of CD28null T-cells, in particular CD28null CD4 T-cells. These cells can directly damage endothelium and precipitate cardiovascular events. However, the current paradigm holds that the accumulation of CD28null T-cells is a normal consequence of aging, whereas the link between these T-cell populations and CMV infection is explained by the increased prevalence of this infection in older people. Resolving whether CMV infection or aging triggers CD28null T-cell expansions is of critical importance because, unlike aging, CMV infection can be treated.Methods: We used multi-color flow-cytometry, antigen-specific activation assays, and HLA-typing to dissect the contributions of CMV infection and aging to the accumulation of CD28null CD4 and CD8 T-cells in CMV+ and CMV- individuals aged 19 to 94 years. Linear/logistic regression was used to test the effect of sex, age, CMV infection, and HLA-type on CD28null T-cell frequencies.Results: The median frequencies of CD28null CD4 T-cells and CD28null CD8 T-cells were >12-fold (p=0.000) but only approximately 2-fold higher (p=0.000), respectively, in CMV+ (n=136) compared with CMV- individuals (n=106). The effect of CMV infection on these T-cell subsets was confirmed by linear regression. Unexpectedly, aging contributed only marginally to an increase in CD28null T-cell frequencies, and only in CMV+ individuals. Interestingly, the presence of HLA-DRB1*0301 led to an approximately 9-fold reduction of the risk of having CD28null CD4 T-cell expansions (OR=0.108, p=0.003). Over 75% of CMV-reactive CD4 T-cells were CD28null.Conclusion: CMV infection and HLA type are major risk factors for CD28null CD4 T-cell-associated cardiovascular pathology. Increased numbers of CD28null CD8 T-cells are also associated with CMV infection, but to a lesser extent. Aging, however, makes only a negligible contribution to the expansion of these T-cell subsets, and only in the presence of CMV infection. Our results open up new avenues for risk assessment, prevention, and treatment.

Expression of CD4+ CD28null T lymphocytes in children and adolescents with type 1 diabetes mellitus: Relation to microvascular complications, aortic elastic properties, and carotid intima media thickness.

Cardiovascular risk in type 1 diabetes mellitus (T1DM) is associated with endothelial dysfunction, inflammation, and altered immunity. CD4+ CD28null T-cells are a subset of long-lived cytotoxic CD4+ T-lymphocytes with proatherogenic and plaque-destabilizing properties. We hypothesized that the frequency of CD4+ CD28null T-cells may be altered in T1DM and related to vascular complications. To assess the percentage of CD4+ CD28null T-lymphocytes in children and adolescents with T1DM and their relation to vascular structure and glycemic control. Totally 100 patients with T1DM were divided into 2 groups according to the presence of microvascular complications and compared with 50 healthy controls. CD4+ CD28null T-lymphocytes were analyzed using flow cytometry. Aortic elastic properties and carotid intima media thickness (CIMT) were assessed. Aortic stiffness index and CIMT were significantly higher among patients compared with healthy controls while aortic strain and distensibility were decreased. The percentage of CD4+ CD28null T-cells was significantly higher in patients with and without microvascular complications compared with controls. High frequency of CD4+ CD28null T-cells was found among patients with microalbuminuria or peripheral neuropathy. Patients with CD4+ CD28null T-cells ≥10% had higher HbA1c, urinary albumin creatinine ratio, aortic stiffness, and CIMT. CD4+ CD28null T-cells were positively correlated to HbA1c, aortic stiffness index, and CIMT. Changes in aortic elastic properties and increased CIMT among young patients with T1DM may enable the recognition of preclinical cardiac impairment. The correlation between CD4+ CD28null T-cells and assessed parameters of vascular structure highlights the role of altered immune response in the occurrence of diabetic vascular complications.

Valaciclovir to prevent Cytomegalovirus mediated adverse modulation of the immune system in ANCA-associated vasculitis (CANVAS): study protocol for a randomised controlled trial.

BackgroundThe ANCA-associated vasculitides (AAV) are systemic autoimmune inflammatory disorders characterised by necrotising inflammation affecting small to medium-sized blood vessels. Despite improvements in survival, infection and cardiovascular disease remain leading causes of morbidity and mortality.Considerable evidence suggests that CD4 + CD28null T-cell expansions, predominantly seen in Cytomegalovirus (CMV) seropositive individuals, are associated with systemic dysregulation of immune function leading to a heightened risk of infection and cardiovascular disease. In patients with AAV, CD4 + CD28null expansions are driven by CMV and are associated with an increased risk of infection and mortality.The aim of this study is to explore in detail the ways in which CMV modulates the immune system and to determine whether treatment with valaciclovir blocks subclinical CMV reactivation in CMV seropositive AAV patients and ameliorates the CMV-induced adverse effects on the immune system.Methods/designCANVAS is a single-centre prospective open-label randomised controlled proof-of-concept trial of 50 adult CMV seropositive patients with stable AAV. Participants will be randomly allocated to receive valaciclovir orally (2 g QDS or reduced according to renal function) or no additional treatment for 6 months with an additional 6-month follow-up period. The primary outcome is the proportion of patients with CMV reactivation, as assessed by measurable viral load on quantitative blood and urine CMV polymerase chain reaction. The secondary outcomes are safety, change in the proportion of CD4+ CMV-specific T-cell population (defined as CD4 + CD28null cells) and change in soluble markers of inflammation from baseline to 6 months. Further tertiary and exploratory outcomes include persistence of the effect of valaciclovir on the proportion of CD4 + CD28null cells at 6 months post completion of treatment, change in the immune phenotype of CD4+ T cells and change in blood pressure and arterial stiffness parameters from baseline to 6 months.DiscussionThe results of this study will enable larger studies to be conducted to determine whether by controlling subclinical CMV reactivation, we can improve clinical endpoints such as infection and cardiovascular disease. The potential impact of this study is not limited to AAV, as CD4 + CD28null cells have been linked to adverse outcomes in other inflammatory conditions and in the context of an ageing immune system.Trial registrationClinicalTrials.gov Identifier NCT01633476 (registered 29 June 2012).Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-016-1482-2) contains supplementary material, which is available to authorized users.

Loss of CD28 on Peripheral T Cells Decreases the Risk for Early Acute Rejection after Kidney Transplantation.

BackgroundEnd-stage renal disease patients have a dysfunctional, prematurely aged peripheral T-cell system. Here we hypothesized that the degree of premature T-cell ageing before kidney transplantation predicts the risk for early acute allograft rejection (EAR).Methods222 living donor kidney transplant recipients were prospectively analyzed. EAR was defined as biopsy proven acute allograft rejection within 3 months after kidney transplantation. The differentiation status of circulating T cells, the relative telomere length and the number of CD31+ naive T cells were determined as T-cell ageing parameters.ResultsOf the 222 patients analyzed, 30 (14%) developed an EAR. The donor age and the historical panel reactive antibody score were significantly higher (p = 0.024 and p = 0.039 respectively) and the number of related donor kidney transplantation was significantly lower (p = 0.018) in the EAR group. EAR-patients showed lower CD4+CD28null T-cell numbers (p<0.01) and the same trend was observed for CD8+CD28null T-cell numbers (p = 0.08). No differences regarding the other ageing parameters were found. A multivariate Cox regression analysis showed that higher CD4+CD28null T-cell numbers was associated with a lower risk for EAR (HR: 0.65, p = 0.028). In vitro, a significant lower percentage of alloreactive T cells was observed within CD28null T cells (p<0.001).ConclusionImmunological ageing-related expansion of highly differentiated CD28null T cells is associated with a lower risk for EAR.

Down-Regulation of Surface CD28 under Belatacept Treatment: An Escape Mechanism for Antigen-Reactive T-Cells.

BackgroundThe co-stimulatory inhibitor of the CD28-CD80/86-pathway, belatacept, allows calcineurin-inhibitor-free immunosuppression in kidney transplantation. However, aggressive T-cell mediated allogeneic responses have been observed in belatacept-treated patients, which could be explained by effector-memory T-cells that lack membrane expression of CD28, i.e. CD28-negative (CD28NULL) T-cells. CD28-positive (CD28POS) T-cells that down regulate their surface CD28 after allogeneic stimulation could also pose a threat against the renal graft. The aim of this study was to investigate this potential escape mechanism for CD28POS T-cells under belatacept treatment.Materials & MethodsPBMCs, isolated T-cell memory subsets and isolated CD28POS T-cells were obtained from end-stage renal disease (ESRD) patients and co-cultured with allo-antigen in the presence of belatacept to mimic allogeneic reactions in kidney-transplant patients under belatacept treatment. As a control, IgG was used in the absence of belatacept.ResultsDespite high in vitro belatacept concentrations, a residual T-cell growth of ±30% was observed compared to the IgG control after allogeneic stimulation. Of the alloreactive T-cells, the majority expressed an effector-memory phenotype. This predominance for effector-memory T-cells within the proliferated cells was even larger when a higher dose of belatacept was added. Contrary to isolated naïve and central-memory T cells, isolated effector-memory T cells could not be inhibited by belatacept in differentiation or allogeneic IFNγ production. The proportion of CD28-positive T cells was lower within the proliferated T cell population, but was still substantial. A fair number of the isolated initially CD28POS T-cells differentiated into CD28NULL T-cells, which made them not targetable by belatacept. These induced CD28NULL T-cells were not anergic as they produced high amounts of IFNγ upon allogeneic stimulation. The majority of the proliferated isolated originally CD28POS T-cells, however, still expressed CD28 and also expressed IFNγ.ConclusionThis study provides evidence that, apart from CD28NULL T-cells, also CD28POS, mostly effector-memory T-cells can mediate allogeneic responses despite belatacept treatment.

Association of Killer Cell Immunoglobulin- Like Receptor Genes in Iranian Patients with Rheumatoid Arthritis.

ObjectivesRheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by persistent synovitis, ultimately leading to cartilage and bone degeneration. Natural Killer cells and CD28 null T-cells are suspected as role players in RA pathogenesis. These cells are similar in feature and function, as they both exert their cytotoxic effect via Killer Cell Immunoglobulin- Like Receptors (KIR) on their surface. KIR genes have either an inhibitory or activating effect depending on their intracytoplasmic structure. Herein we genotyped 16 KIR genes, 3 pseudo genes and 6 HLA class І genes as their corresponding ligands in RA patients and control subjects.MethodsIn this case-control study, KIR and HLA genes were genotyped in 400 RA patients and 372 matched healthy controls using sequence-specific primers (SSP-PCR). Differences in the frequency of genes and haplotypes were determined by χ² test.Results KIR2DL2, 2DL5a, 2DL5b and activating KIR: KIR2DS5 and 3DS1 were all protective against RA. KIR2DL5 removal from a full Inhibitory KIR haplotype converted the mild protection (OR = 0.56) to a powerful predisposition to RA (OR = 16.47). Inhibitory haplotype No. 7 comprising KIR2DL5 in the absence of KIR2DL1 and KIR2DL3 confers a 14-fold protective effect against RA.ConclusionIndividuals carrying the inhibitory KIR haplotype No. 6 have a high potential risk for developing RA.