T-cell-mediated lysis of endothelial cells in acute coronary syndromes

Effects of drospirenone-ethinylestradiol and/or metformin on CD4(+)CD28(null) T lymphocytes frequency in women with hyperinsulinemia having polycystic ovary syndrome: a randomized clinical trial

OBJECTIVE

To evaluate the long-term effects of drospirenone (DRSP)/ethinylestradiol (EE) alone, metformin alone, and DRSP/EE-metformin on CD4(+)CD28(null) T lymphocytes frequency, a cardiovascular risk marker, in patients with hyperinsulinemic polycystic ovary syndrome (PCOS).

DESIGN

Randomized clinical trial.

INTERVENTIONS

Ninety three patients with hyperinsulinemic PCOS were age matched and body mass index matched and randomized to receive a 6 months daily treatment with DRSP (3 mg)/EE (0.03 mg), or metformin (1500 mg), or DRSP/EE combined with metformin.

MAIN OUTCOME MEASURES

CD4(+)CD28(null) T-cell frequencies.

RESULTS

The DRSP/EE and metformin groups did not show any significant change in the CD4(+)CD28(null) frequency compared to the baseline. Interestingly, a statistically significant decrease in CD4(+)CD28(null) frequency occurred after 6 months of DRSP/EE-metformin (median 3-1.5; P < .01). Of note, this statistically significant association was confirmed after adjusting for baseline values in DRSP/EE-metformin group by analysis of covariance (P < .05).

CONCLUSIONS

In women with hyperinsulinemic PCOS, combined therapy with DRSP/EE and metformin may reduce cardiovascular risk.

Characterization of CD4+CD28null T cells in patients with coronary artery disease and individuals with risk factors for atherosclerosis

Risk factors for atherosclerosis may contribute to chronic low-grade inflammation. A highly cytotoxic and inflammatory CD4(+) cell subset (CD4(+)CD28(null) cells) has been associated with inflammatory diseases, including acute coronary syndromes (ACS). The aim of this study was to quantify and characterize CD4(+)CD28(null) cells in individuals with risk factors for atherosclerosis and patients with coronary artery disease (CAD). In order to achieve this goal, peripheral blood mononuclear cells (PBMCs) from individuals with risk factors for atherosclerosis and patients with CAD were analyzed using flow cytometry to detect cytotoxic molecules and evaluate the expression of homing receptors and inflammatory cytokines in CD4(+) cell subsets. The cells were evaluated ex vivo and after stimulation in culture. We found no differences in the proportions of CD4(+)CD28(null) cells among the groups. Compared with the CD4(+)CD28(+) population, the ex vivo CD4(+)CD28(null) subset from all groups expressed higher levels of granzymes A and B, perforin, granulysin and interferon-γ (IFN-γ). Individuals with risk factors and patients with ACS showed the highest levels of cytotoxic molecules. After stimulation, tumor necrosis factor-α (TNF-α) expression in the CD4(+)CD28(null) subset from these groups increased more than in the other groups. Stimulation with LPS decreased the expression of cytotoxic molecules by CD4(+)CD28(null) cells in all groups. In conclusion, our results show that risk factors for atherosclerosis may alter the CD4(+)CD28(null) cells phenotype, increasing their cytotoxic potential. Our findings also suggest that CD4(+)CD28(null) cells may participate in the early phases of atherosclerosis.

T cell replicative senescence in human aging

The decline of the immune system appears to be an intractable consequence of aging, leading to increased susceptibility to infections, reduced effectiveness of vaccination and higher incidences of many diseases including osteoporosis and cancer in the elderly. These outcomes can be attributed, at least in part, to a phenomenon known as T cell replicative senescence, a terminal state characterized by dysregulated immune function, loss of the CD28 costimulatory molecule, shortened telomeres and elevated production of proinflammatory cytokines. Senescent CD8 T cells, which accumulate in the elderly, have been shown to frequently bear antigen specificity against cytomegalovirus (CMV), suggesting that this common and persistent infection may drive immune senescence and result in functional and phenotypic changes to the T cell repertoire. Senescent T cells have also been identified in patients with certain cancers, autoimmune diseases and chronic infections, such as HIV. This review discusses the in vivo and in vitro evidence for the contribution of CD8 T cell replicative senescence to a plethora of age-related pathologies and a few possible therapeutic avenues to delay or prevent this differentiative end-state in T cells. The age-associated remodeling of the immune system, through accumulation of senescent T cells has farreaching consequences on the individual and society alike, for the current healthcare system needs to meet the urgent demands of the increasing proportions of the elderly in the US and abroad.

Adaptive immunity, inflammation, and cardiovascular complications in type 1 and type 2 diabetes mellitus

Diabetes mellitus (DM) is a pandemics that affects more than 170 million people worldwide, associated with increased mortality and morbidity due to coronary artery disease (CAD). In type 1 (T1) DM, the main pathogenic mechanism seems to be the destruction of pancreatic β -cells mediated by autoreactive T-cells resulting in chronic insulitis, while in type 2 (T2) DM primary insulin resistance, rather than defective insulin production due to β -cell destruction, seems to be the triggering alteration. In our study, we investigated the role of systemic inflammation and T-cell subsets in T1- and T2DM and the possible mechanisms underlying the increased cardiovascular risk associated with these diseases.

T lymphocyte autoreactivity in inflammatory mechanisms regulating atherosclerosis

Atherosclerosis has been clearly demonstrated to be a chronic inflammatory disease of the arterial wall. Both cells of the innate and the acquired immune system, particularly monocytes and T lymphocytes, are implicated in the atherogenic process, producing different cytokines with pro- and anti-inflammatory effects. The majority of pathogenic T cells involved in atherosclerosis are of the Th1 profile, that has been correlated positively with coronary artery disease. Many studies conducted to evaluate the molecular factors responsible for the activation of T cells have demonstrated that the main antigenic targets in atherosclerosis are modified endogenous structures. These self-molecules activate autoimmune reactions mainly characterized by the production of Th1 cytokines, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper we will summarize the different T-cell subsets involved in atherosclerosis and the best characterized autoantigens involved in cardiovascular inflammation.

Vitamin D deficiency, CD4+CD28null cells and accelerated atherosclerosis in chronic kidney disease

AIM

Cardiovascular disease (CVD) is the leading cause of death among chronic kidney disease (CKD) patients. The role of vitamin D remains controversial in this process. We evaluated the relationship between 25-hydroxyvitamin D, abnormal T helper cells (CD4+CD28null cells), systemic inflammation and atherosclerosis in CKD patients.

METHODS

A total of 101 stage 4-5 non-dialysis CKD patients and 40 healthy controls were studied. Common carotid artery intima media thickness (CCA-IMT) was measured with an ultrasound system. 25(OH) vitamin D and highly sensitive C-reactive protein (hsCRP) were measured in serum by enzyme linked immunosorbent assay. The frequency of circulating CD4+CD28null cells was evaluated by flowcytometry.

RESULTS

CKD subjects exhibited higher CCA-IMT (0.71 ± 0.01 vs 0.56 ± 0.01 mm, P < 0.0001), hsCRP (90.7 ± 5.8 vs 50.1 ± 8.6 µg/mL, P < 0.0001), CD4+CD28null cell frequency (9.1 ± 0.9 vs 3.6 ± 0.5%, P < 0.0001) and lower 25(OH) vitamin D levels (17.9 ± 1.9 vs 26.9 ± 3.5 ng/mL, P < 0.0001). In CKD subjects, serum 25 (OH) vitamin D level showed a strong inverse correlation with CCA-IMT (r = -0.729, P < 0.0001) and correlated with CD4+CD28null cell frequency (r = -0.249, P = 0.01) and hsCRP (r = -0.2, P = 0.047). We also noted correlation of IMT with patient age (r = 0.291, P = 0.004) and CD4+CD28null cells (r = 0.34, P = 0.001). On multiple regression analysis, 25(OH) vitamin D level, diabetic status and CD4+CD28null cell frequency exhibited independent association with IMT in CKD subjects.

CONCLUSIONS

Vitamin D deficiency, inflammatory activation and higher frequency of CD4+CD28null T lymphocyte population correlate with preclinical atherosclerotic changes in CKD population. These findings suggest possible linkage between vitamin D metabolism and T cell modulation - abnormalities that may contribute to development of atherosclerosis in CKD.

CD4(+)CD28(null) T lymphocyte frequency, a new marker of cardiovascular risk: relationship with polycystic ovary syndrome phenotypes

OBJECTIVE

To study the frequency of CD4(+)CD28(null) T cells, which are aggressive T lymphocytes associated with recurrent coronary instability and type 2 diabetes mellitus, in different polycystic ovary syndrome (PCOS) phenotypes and in age- and body mass index-matched healthy women.

DESIGN

Retrospective cohort observational study.

SETTING

Unit of human reproductive pathophysiology, university hospital.

PATIENT(S)

A total of 167 PCOS patients and 102 control subjects.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

CD4(+)CD28(null) T cell frequency, high-sensitive C-reactive protein levels, and other glucose-metabolic parameters.

RESULT(S)

CD4(+)CD28(null) frequency was significantly higher in all PCOS groups than in control subjects. CD4(+)CD28(null) frequency was significantly higher in nonhyperandrogenic phenotype (5.7%, range 3.2-7.1) than in phenotypes with hyperandrogenism (H) + oligoamenorrhea (O) + polycystic ovary (PCO) (3.5%, range 1-5.8), H + O (3%, range 1.8-4.7), and H + PCO (2.63%, range 1.2-4.1). The relative risk of non-H phenotype for PCOS women in the highest quartile for CD4(+)CD28(null) frequency compared with PCOS women with the lowest quartile was 3.2 (95% confidence interval 1.9-5.8).

CONCLUSION(S)

Cardiovascular risk evaluation should be performed in all PCOS phenotypes. In particular, we demonstrated that the non-H phenotype has potentially increased cardiovascular risk in terms of CD4(+)CD28(null) frequency.

Prevalence of circulating CD4+CD28null T cells is associated with early atherosclerotic damage in patients with end-stage renal disease undergoing hemodialysis

CD4(+) T-cell subsets lacking surface CD28 in peripheral blood have been suggested to predispose people to atherosclerosis. To determine if CD4(+)CD28(null) T cells are involved in the immunopathological process of atherosclerotic damage in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD), we characterized peripheral-blood CD4(+)CD28(null) T cells from HD patients and investigated the association between these cells and early atherosclerotic damage. Four color flow cytometric analyses showed that HD patients had significantly higher percentages of CD4(+)CD28(null) T cells in circulating blood than healthy subjects (HS). Most HD patient-derived CD4(+)CD28(null) T cells expressed higher levels of CX3CR1 and produced more intracellular IFN-γ, perforin and granzyme B than their counterparts. Regression analyses demonstrated that the increased levels of CD4(+)CD28(null) T cells were positively correlated to serum levels of C-reactive protein, suggesting systemic inflammation and atherosclerosis. Furthermore, phenotypic and functional studies of CD4(+)CD28(null) T cells showed that these cells were closely correlated with impaired flow-mediated vasodilation and increased intima-media thickness in the carotid artery, which are markers of early atherosclerosis. These data suggested that CD4(+)CD28(null) T cells are important effector cells in HD patients, and that these cells may have a critical role in mediating early atherosclerotic damage.

Pathogenic features of CD4+CD28- T cells in immune disorders

Aging of the immune system contributes to the increased morbidity and mortality of the elderly population and may occur prematurely in patients with immune disorders. One of the main characteristics of immunosenescence is the expansion of CD4(+)CD28(-) T cells in the blood. These cells are effector memory T cells with cytotoxic capacity, and have been recently described to have pathogenic potential in a variety of immune disorders. Interestingly, CD4(+)CD28(-) T cells have now been found to infiltrate target tissues of patients with multiple sclerosis, rheumatoid arthritis, myopathies, acute coronary syndromes, and other immune-related diseases. In this review, we discuss potential factors and mechanisms that may induce the expansion of these cells, as well as their putative pathogenic mechanisms in immune disorders.

Immune aging and autoimmunity

Age is an important risk for autoimmunity, and many autoimmune diseases preferentially occur in the second half of adulthood when immune competence has declined and thymic T cell generation has ceased. Many tolerance checkpoints have to fail for an autoimmune disease to develop, and several of those are susceptible to the immune aging process. Homeostatic T cell proliferation which is mainly responsible for T cell replenishment during adulthood can lead to the selection of T cells with increased affinity to self- or neoantigens and enhanced growth and survival properties. These cells can acquire a memory-like phenotype, in particular under lymphopenic conditions. Accumulation of end-differentiated effector T cells, either specific for self-antigen or for latent viruses, have a low activation threshold due to the expression of signaling and regulatory molecules and generate an inflammatory environment with their ability to be cytotoxic and to produce excessive amounts of cytokines and thereby inducing or amplifying autoimmune responses.

Apoptotic effects of antilymphocyte globulins on human pro-inflammatory CD4+CD28- T-cells

Background

Pro-inflammatory, cytotoxic CD4⁺CD28⁻ T-cells with known defects in apoptosis have been investigated as markers of premature immuno-senescence in various immune-mediated diseases. In this study we evaluated the influence of polyclonal antilymphocyte globulins (ATG-Fresenius, ATG-F) on CD4⁺CD28⁻ T-cells in vivo and in vitro.

Principal Findings

Surface and intracellular three colour fluorescence activated cell sorting analyses of peripheral blood mononuclear cells from 16 consecutive transplant recipients and short-term cell lines were performed. In vivo, peripheral levels of CD3⁺CD4⁺CD28⁻ T-cells decreased from 3.7±7.1% before to 0±0% six hours after ATG-F application (P = 0.043) in 5 ATG-F treated but not in 11 control patients (2.9±2.9% vs. 3.9±3.0%). In vitro, ATG-F induced apoptosis even in CD4⁺CD28⁻ T-cells, which was 4.3-times higher than in CD4⁺CD28⁺ T-cells. ATG-F evoked apoptosis was partially reversed by the broad-spectrum caspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD-fmk) and prednisolon-21-hydrogensuccinate. ATG-F triggered CD25 expression and production of pro-inflammatory cytokines, and induced down-regulation of the type 1 chemokine receptors CXCR-3, CCR-5, CX3CR-1 and the central memory adhesion molecule CD62L predominately in CD4⁺CD28⁻ T-cells.

Conclusion

In summary, in vivo depletion of peripheral CD3⁺CD4⁺CD28⁻ T-cells by ATG-F in transplant recipients was paralleled in vitro by ATG-F induced apoptosis. CD25 expression and chemokine receptor down-regulation in CD4⁺CD28⁻ T-cells only partly explain the underlying mechanism.

The CD4+ T-cell subset lacking expression of the CD28 costimulatory molecule is expanded and shows a higher activation state in multiple sclerosis

Multiple sclerosis (MS) is a chronic debilitating disease, in which T-cells are considered to play a pivotal role. CD28 is the quintessential costimulatory molecule on T-cells and its expression declines progressively with repeated stimulations, leading to the generation of CD28(-) T-cells. Our aim was to examine whether CD4(+)CD28(-) T-cells were enriched in MS patients, and characterize the phenotype of this subset in MS patients and healthy controls (HC). All these changes could provide these CD4(+)CD28(-) T-cell characteristics that might be involved in the pathogenesis of MS, turning this T-cell subset into a potential target for future therapeutic strategies.

Dynamic immune cell accumulation during flow-induced atherogenesis in mouse carotid artery: an expanded flow cytometry method

OBJECTIVE

Inflammation plays a central role in atherosclerosis. However, the detailed changes in the composition and quantity of leukocytes in the arterial wall during atherogenesis are not fully understood in part because of the lack of suitable methods and animal models.

METHODS AND RESULTS

We developed a 10-fluorochrome, 13-parameter flow cytometry method to quantitate 7 major leukocyte subsets in a single digested arterial wall sample. Apolipoprotein E-deficient mice underwent left carotid artery (LCA) partial ligation and were fed a high-fat diet for 4 to 28 days. Monocyte/macrophages, dendritic cells, granulocytes, natural killer cells, and CD4 T cells significantly infiltrated the LCA as early as 4 days. Monocyte/macrophages and dendritic cells decreased between 7 and 14 days, whereas T-cell numbers remained steady. Leukocyte numbers peaked at 7 days, preceding atheroma formation at 14 days. B cells entered LCA by 14 days. Control right carotid and sham-ligated LCAs showed no significant infiltrates. Polymerase chain reaction and ELISA arrays showed that expression of proinflammatory cytokines and chemokines peaked at 7 and 14 days postligation, respectively.

CONCLUSION

This is the first quantitative description of leukocyte number and composition over the life span of murine atherosclerosis. These results show that disturbed flow induces rapid and dynamic leukocyte accumulation in the arterial wall during the initiation and progression of atherosclerosis.

CX(3)CR1 drives cytotoxic CD4(+)CD28(-) T cells into the brain of multiple sclerosis patients

Immunosenescence, or ageing of the immune system, contributes to the increased morbidity and mortality seen in the elderly population. Premature immunosenescence is shown to occur in a subgroup of patients with autoimmune diseases. One of the main characteristics of immunosenescence is the expansion of CD4(+)CD28(-) T cells in the blood. In this study, we investigate the potential contribution of these cells to disease processes in a subgroup of multiple sclerosis (MS) and rheumatoid arthritis (RA) patients. Characterization of CD4(+)CD28(-) T cells in patients and healthy controls reveals that they have an inflammation-seeking effector-memory T cell phenotype with cytotoxic properties, as they expel cytotoxic granules in response to a polyclonal stimulus or MS-related autoantigens. We identify CX(3)CR1, the fractalkine receptor, as a selective marker to discriminate CD4(+)CD28(-) T cells from their CD4(+)CD28(+) counterparts. CX(3)CR1 expression enables CD4(+)CD28(-) T cells to migrate towards a fractalkine gradient in vitro. In addition, we find increased levels of fractalkine in the cerebrospinal fluid and inflammatory lesions of MS patients. We demonstrate for the first time that CD4(+)CD28(-) T cells accumulate in MS lesions of a subgroup of patients. Moreover, we have indications that these cells are cytotoxic in the target tissue. Overall, our findings suggest that CD4(+)CD28(-) T cells migrate in response to a chemotactic gradient of fractalkine to sites of inflammation, where they contribute to the inflammatory processes in a subgroup of patients with MS and RA.

PSGL-1-expressing CD4 T cells induce endothelial cell apoptosis in perimenopausal women

AIM

Menopause and subsequent estrogen deficiency correlate with the development of atherosclerosis and cardiovascular diseases in women. However, the relationship between estrogen deficiency and development of atherosclerosis with inflammatory infiltrates is not fully understood. We sought to determine whether perimenopausal women (PMW) exhibited T cell dysfunction related to the expression of adhesion molecules and accelerated endothelial cell (EC) apoptosis.

METHODS

Fresh CD4 T cells were isolated from 48 PMW and 54 healthy control women with regular menstrual cycles (CW), and investigated cytotoxicity to ECs by apoptosis assay. The adhesion molecules on CD4 T cells were examined by flow cytometry. CD4 T cell rolling and adhesion on ECs were analyzed by adhesion assay under laminar flow.

RESULTS

CD4 T cells from PMW with low estradiol levels induced significant EC apoptosis (P = 0.0152). Furthermore, cytotoxic CD4 T cells from PMW strongly expressed P-selectin glycoprotein ligand-1 (PSGL-1) and integrin β2 (P < 0.0001 and P = 0.0285, respectively) but not L-selectin or integrin αM when compared to CD4 T cells from CW. Estradiol levels negatively correlated with only PSGL-1 expression (R = -0.781, P = 0.0002), and estradiol treatments inhibited both PSGL-1 expression (P = 0.0133) and T cell-induced EC apoptosis (P = 0.018). An estrogen receptor antagonist inhibited these effects of estradiol (P = 0.0355 and P = 0.0097, respectively). Moreover, PSGL-1 expression correlated with T cell adhesion to ECs under laminar flow conditions (R = 0.636, P = 0.0355) and with EC apoptosis (R = 0.614, P = 0.0196). PSGL-1 specific antibodies effectively suppressed T cell adhesion (P = 0.0057) and EC apoptosis (P = 0.001) indicating that CD4 T cell-mediated EC apoptosis depended on PSGL-1 adhesion in PMW.

CONCLUSIONS

PSGL-1-expressing cytotoxic CD4 T cells are abundant in PMW with low estradiol levels may contribute to T cell-mediated atherosclerotic development.

Differential expression of NK receptors CD94 and NKG2A by T cells in rheumatoid arthritis patients in remission compared to active disease

Objective

TNF inhibitors (TNFi) have revolutionised the treatment of rheumatoid arthritis (RA). Natural killer (NK) cells and Natural Killer Cell Receptor⁺ T (NKT) cells comprise important effector lymphocytes whose activity is tightly regulated through surface NK receptors (NKRs). Dysregulation of NKRs in patients with autoimmune diseases has been shown, however little is known regarding NKRs expression in patients with TNFi-induced remission and in those who maintain remission vs disease flare following TNFi withdrawal.

Methods

Patients with RA were recruited for this study, (i) RA patients in clinical remission following a minimum of one year of TNFi therapy (n = −15); (2) Active RA patients, not currently or ever receiving TNFi (n = 18); and healthy control volunteers (n = 15). Patients in remission were divided into two groups: those who were maintained on TNFi and those who withdrew from TNFi and maintained on DMARDS. All patients underwent full clinical assessment. Peripheral blood mononuclear cells were isolated and NKR (CD94, NKG2A, CD161, CD69, CD57, CD158a, CD158b) expression on T-(CD3⁺CD56⁻), NK-(CD3⁻CD56⁺) and NKT-(CD3⁺CD56⁺) cells was determined by flow cytometry.

Results

Following TNFi withdrawal, percentages and numbers of circulating T cells, NK cells or NKT cell populations were unchanged in patients in remission versus active RA or HCs. Expression of the NKRs CD161, CD57, CD94 and NKG2A was significantly increased on CD3⁺CD56-T cells from patients in remission compared to active RA (p<0.05). CD3⁺CD56-T cell expression of CD94 and NKG2A was significantly increased in patients who remained in remission compared with patients whose disease flared (p<0.05), with no differences observed for CD161 and CD57. CD3⁺CD56⁻ cell expression of NKG2A was inversely related to DAS28 (r = −0.612, p<0.005).

Conclusion

High CD94/NKG2A expression by T cells was demonstrated in remission patients following TNFi therapy compared to active RA, while low CD94/NKG2A were associated with disease flare following withdrawal of therapy.

Cellular immunity, low-density lipoprotein and atherosclerosis: break of tolerance in the artery wall

Atherosclerosis is a chronic inflammatory disease. Atherosclerotic plaques contain abundant immune cells that can dictate and effect inflammatory responses. Among them, T cells are present during all stages of the disease suggesting that they are essential in the initiation as well as the progression of plaque. Experimental as well as clinical research has demonstrated different T cell subsets, i.e. CD4+ Th1, Th2, Th17, and Treg as well as CD8+ and NKT cells in the plaque. Moreover, candidate antigens inducing T cell responses have been identified. Knowledge about the pathological role of these cells in atherogenesis may lead to development of new therapies. This review provides an overview of the research field of cellular immunity in atherosclerosis. It emphasises the events and findings involving antigen specific T cells, in particular low-density lipoprotein-specific T cells.

Epigenetics in systemic lupus erythematosus: leading the way for specific therapeutic agents

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder of an unclearly determined etiology. Past studies, both epidemiological and biological, have implicated epigenetic influences in disease etiology and pathogenesis. Epigenetics describes changes in gene expression not linked to alterations in the underlying genomic sequence, and is most often typified by three modifications: methylation of DNA, addition of various side chains to histone groups and transcriptional regulation via short ncRNA sequences. The purpose of this article is to review the most important advances that link epigenetic changes to lupus. The contribution of DNA methylation changes to lupus pathogenesis is discussed. These include the role of apoptotic DNA, ultraviolet radiation, endogenous retroviruses, dietary contributions and aging. Hypomethylation of specific genes overexpressed in lupus T cells such as ITGAL (CD11a), CD40LG (CD40L), TNFSF7 (CD70), KIR2DL4 and PRF1 (perforin), and CD5 in lupus B cells seem to play an important role. Moreover, histone modifications such as increased global H4 acetylation in monocytes are highly associated with SLE. NcRNAs, especially miR-21, miR-148a and miR-126, control other elements of epigenetic regulation; particularly, transcription of the maintenance DNA methylation enzyme DNMT1. Epigenetic contributions to SLE etiology have been well established, but much is still unknown. Epigenome-wide studies coupled with functional analysis of the epigenomic changes discovered will uncover novel pathways important in disease pathogenesis. Epigenetic therapies for SLE may be feasible in the future, particularly if they are designed to target specific regions within the genome.

Role of unusual CD4+ CD28- T cells in acute coronary syndrome

Acute coronary syndrome (ACS) is a group of clinical symptoms that results from complete or partial occlusive thrombus, which is caused by coronary an atherosclerotic plaque rupture or erosion. According to a recent study, CD4(+) CD28(-) T cells are found in atherosclerotic plaques and the peripheral circulation blood in patients with ACS, these cells play an important role in plaque ruptures. CD4(+) CD28(-) T cells are an unusual subset of helper cells, which expand and have harmful effects in ACS. In this review, we discuss the current issues on the generation of CD4(+) CD28(-) T cells and focus on their phenotypic and functional characteristics relevant to the development of cardiovascular events. Targeting the CD4(+) CD28(-) T cells subset in ACS could provide novel therapeutic means to prevent acute life-threatening coronary events.

Atherosclerosis in psoriatic arthritis

The atherosclerotic process is accelerated in several autoimmune rheumatic diseases. Effector cells of innate and adaptive immunity along with pro-inflammatory cytokines and other immune mediators are found in atherosclerotic lesions, where they play an important role in induction, progression and rupture of plaques. Psoriatic arthritis (PsA) is a chronic inflammatory disease, characterized by arthritis, enthesitis, dactilytis, osteitis, and axial involvement, along with skin manifestations. PsA is frequently associated with obesity, diabetes, dyslipidemia, hypertension, accelerated atherosclerosis and with increased cardiovascular morbidity and mortality. Disease-specific and traditional risk factors seem to account for the atherosclerotic burden in PsA patients. Some immunological factors which are involved in PsA can also contribute to atherosclerosis including C reactive protein (CRP), TNF-α, IFN-γ, IL-1, Il 6, IL23, and Th17.

Rosuvastatin, inflammation, C-reactive protein, JUPITER, and primary prevention of cardiovascular disease--a perspective

The major public health concern worldwide is coronary heart disease, with dyslipidemia as a major risk factor. Statin drugs are recommended by several guidelines for both primary and secondary prevention. Rosuvastatin has been widely accepted because of its efficacy, potency, and superior safety profile. Inflammation is involved in all phases of atherosclerosis, with the process beginning in early youth and advancing relentlessly for decades throughout life. C-reactive protein (CRP) is a well-studied, nonspecific marker of inflammation which may reflect general health risk. Considerable evidence suggests CRP is an independent predictor of future cardiovascular events, but direct involvement in atherosclerosis remains controversial. Rosuvastatin is a synthetic, hydrophilic statin with unique stereochemistry. A large proportion of patients achieve evidence-based lipid targets while using the drug, and it slows progression and induces regression of atherosclerotic coronary lesions. Rosuvastatin lowers CRP levels significantly. The Justification for Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial was designed after the observation that when both low density lipoprotein and CRP were reduced, patients fared better than when only LDL was lowered. Advocates and critics alike acknowledge that the benefits of rosuvastatin in JUPITER were real. After a review, the US Food and Drug Administration extended the indications for rosuvastatin to include asymptomatic JUPITER-eligible individuals with one additional risk factor. The American Heart Association and Centers of Disease Control and Prevention had previously recognized the use of CRP in persons with "intermediate risk" as defined by global risk scores. The Canadian Cardiovascular Society guidelines went further and recommended use of statins in persons with low LDL and high CRP levels at intermediate risk. The JUPITER study focused attention on ostensibly healthy individuals with "normal" lipid profiles and high CRP values who benefited from statin therapy. The backdrop to JUPITER during this period was an increasing awareness of a rising cardiovascular risk burden and imperfect methods of risk evaluation, so that a significant number of individuals were being denied beneficial therapies. Other concerns have been a high level of residual risk in those who are treated, poor patient adherence, a need to follow guidelines more closely, a dual global epidemic of obesity and diabetes, and a progressively deteriorating level of physical activity in the population. Calls for new and more effective means of reducing risk for coronary heart disease are intensifying. In view of compelling evidence supporting earlier and aggressive therapy in people with high risk burdens, JUPITER simply offers another choice for stratification and earlier risk reduction in primary prevention patients. When indicated, and in individuals unwilling or unable to change their diet and lifestyles sufficiently, the benefits of statins greatly exceed the risks. Two side effects of interest are myotoxicity and an increase in the incidence of diabetes.

Ischemia/reperfusion injury: The role of immune cells

Ischemia/reperfusion (I/R) injury is an inflammatory condition that is characterized by innate immunity and an adaptive immune response. This review is focused on the acute inflammatory response in I/R injury, and also the adaptive immunological mechanisms in chronic ischemic disease that lead to increased vulnerability during acute events, in relation to the cell types that have been shown to mediate innate immunity to an adaptive immune response in I/R, specifically myocardial infarction. Novel aspects are also highlighted in respect to the mechanisms within the cardiovascular system and cardiovascular risk factors that may be involved in the inflammatory response accompanying myocardial infarction. Experimental myocardial I/R has suggested that immune cells may mediate reperfusion injury. Specifically, monocytes, macrophages, T-cells, mast cells, platelets and endothelial cells are discussed with reference to the complement cascade, toll-like receptors, cytokines, oxidative stress, renin-angiotensin system, and in reference to the microvascular system in the signaling mechanisms of I/R. Finally, the findings of the data summarized in this review are most important for possible translation into clinical cardiology practice and possible avenues for drug development.

Immune aging and rheumatoid arthritis

Immunologic models of rheumatoid arthritis (RA) have to take into account that the disease occurs at an age when immunocompetence is declining and in a host whose immune system shows evidence of accelerated immune aging. By several immune aging biomarkers, the immune system in patients with RA is prematurely aged by more than 20 years. One major pathogenetic mechanism is a defect in telomere maintenance and DNA repair that causes accelerated cell death. These findings in RA are reminiscent of murine autoimmunity models, in which lymphopenia was identified as a major risk factor for autoimmunity. Progress in the understanding of how accelerated immune aging is pathogenetically involved in RA may allow development of new therapeutic approaches that go beyond the use of anti-inflammatory agents and eventually could open new avenues for preventive intervention.

Biomarkers in acute myocardial infarction

Myocardial infarction causes significant mortality and morbidity. Timely diagnosis allows clinicians to risk stratify their patients and select appropriate treatment. Biomarkers have been used to assist with timely diagnosis, while an increasing number of novel markers have been identified to predict outcome following an acute myocardial infarction or acute coronary syndrome. This may facilitate tailoring of appropriate therapy to high-risk patients. This review focuses on a variety of promising biomarkers which provide diagnostic and prognostic information. Heart-type Fatty Acid Binding Protein and copeptin in combination with cardiac troponin help diagnose myocardial infarction or acute coronary syndrome in the early hours following symptoms. An elevated N-Terminal Pro-B-type Natriuretic Peptide has been well validated to predict death and heart failure following a myocardial infarction. Similarly other biomarkers such as Mid-regional pro-Atrial Natriuretic Peptide, ST2, C-Terminal pro-endothelin 1, Mid-regional pro-Adrenomedullin and copeptin all provide incremental information in predicting death and heart failure. Growth differentiation factor-15 and high-sensitivity C-reactive protein predict death following an acute coronary syndrome. Pregnancy associated plasma protein A levels following chest pain predicts risk of myocardial infarction and revascularisation. Some biomarkers such as myeloperoxidase and high-sensitivity C-reactive protein in an apparently healthy population predicts risk of coronary disease and allows clinicians to initiate early preventative treatment. In addition to biomarkers, various well-validated scoring systems based on clinical characteristics are available to help clinicians predict mortality risk, such as the Thrombolysis In Myocardial Infarction score and Global Registry of Acute Coronary Events score. A multimarker approach incorporating biomarkers and clinical scores will increase the prognostic accuracy. However, it is important to note that only troponin has been used to direct therapeutic intervention and none of the new prognostic biomarkers have been tested and proven to alter outcome of therapeutic intervention. Novel biomarkers have improved prediction of outcome in acute myocardial infarction, but none have been demonstrated to alter the outcome of a particular therapy or management strategy. Randomised trials are urgently needed to address this translational gap before the use of novel biomarkers becomes common practice to facilitate tailored treatment following an acute coronary event.

Statins reduce endothelial cell apoptosis via inhibition of TRAIL expression on activated CD4 T cells in acute coronary syndrome

OBJECTIVE

Statins reduce cardiovascular-related morbidity and mortality, but their effects on inflammation in atherosclerosis are not fully understood. We investigated whether statins can modulate cytotoxic functions of CD4 T cells in acute coronary syndrome (ACS).

METHODS AND RESULTS

Fresh CD4 T cells were isolated from 55 patients with ACS without statin treatment on admission and from 34 age-matched controls. CD4 T cells collected from ACS patients induced endothelial cell apoptosis significantly more than control T cells. The TNF-related apoptosis-inducing ligand (TRAIL) receptor DR5 was strongly upregulated on endothelial cells, and TRAIL-specific antibodies effectively blocked CD4 T cell-mediated apoptosis, indicating that T cell-mediated endothelial death was dependent on the TRAIL pathway. Expression of both the activating antigen CD69 and TRAIL was enhanced on ACS T cells. In in-vitro assays rosuvastatin, fluvastatin, and pitavastatin directly blocked CD4 T cell-mediated endothelial cell apoptosis and reduced T cell-expression of CD69 and TRAIL through TCR-induced Extracellar signal-Regulated Kinases (ERK) activation.

CONCLUSIONS

Activated CD4 T cells expressing TRAIL are enriched in the blood of ACS patients and induce endothelial injury, which may contribute to the destabilization of the plaque. Early statin therapy may suppress T cell-mediated endothelial cell damage in atherosclerotic plaques and thus prevent cardiovascular events.

CD28 down-regulation on circulating CD4 T-cells is associated with poor prognoses of patients with idiopathic pulmonary fibrosis

Background

Although the etiology of idiopathic pulmonary fibrosis (IPF) remains perplexing, adaptive immune activation is evident among many afflicted patients. Repeated cycles of antigen-induced proliferation cause T-cells to lose surface expression of CD28, and we hypothesized this process might also occur in IPF.

Methodology/Principal Findings

Peripheral blood CD4 T-cells from 89 IPF patients were analyzed by flow cytometry and cytokine multiplex assays, and correlated with clinical events. In comparison to autologous CD4⁺CD28⁺cells, the unusual CD4⁺CD28^null lymphocytes seen in many IPF patients had discordant expressions of activation markers, more frequently produced cytotoxic mediators perforin (2.4±0.8% vs. 60.0±7.4%, p<0.0001) and granzyme B (4.5±2.8% vs.74.9±6.5%, p<0.0001), produced greater amounts of many pro-inflammatory cytokines, and less frequently expressed the regulatory T-cell marker FoxP3 (12.9±1.1% vs. 3.3±0.6% p<0.0001). Infiltration of CD4⁺CD28^null T-cells in IPF lungs was confirmed by confocal microscopy. Interval changes of CD28 expression among subjects who had replicate studies were correlated with conterminous changes of their forced vital capacities (r_s = 0.49, p = 0.012). Most importantly, one-year freedom from major adverse clinical events (either death or lung transplantation) was 56±6% among 78 IPF patients with CD4⁺CD28⁺/CD4_total≥82%, compared to 9±9% among those with more extensive CD28 down-regulation (CD4⁺CD28⁺/CD4_total<82%) (p = 0.0004). The odds ratio for major adverse events among those with the most extensive CD28 down-regulation was 13.0, with 95% confidence intervals 1.6-111.1.

Conclusions/Significance

Marked down-regulation of CD28 on circulating CD4 T-cells, a result of repeated antigen-driven proliferations, is associated with poor outcomes in IPF patients. The CD4⁺CD28^null cells of these patients have potentially enhanced pathogenic characteristics, including increased productions of cytotoxic mediators and pro-inflammatory cytokines. These findings show proliferative T-cell responses to antigen(s) resulting in CD28 down-regulation are associated with progression and manifestations of IPF, and suggest assays of circulating CD4 T-cells may identify patients at greatest risk for clinical deterioration.

Insufficient deactivation of the protein tyrosine kinase lck amplifies T-cell responsiveness in acute coronary syndrome

RATIONALE

In the vulnerable atherosclerotic plaque, T cells may destabilize the tissue structure through direct cell-injurious effector functions. T cells transmit environmental signals, such as recognition of antigen, into cellular responses through regulated phosphorylation of cytoplasmic proteins, with the Src family kinase Lck (lymphocyte-specific protein tyrosine kinase) in critical membrane-proximal position of the T-cell receptor (TCR) signaling cascade. The balance between protein phosphorylation and dephosphorylation defines the signal transduction threshold and determines appropriate T-cell responses.

OBJECTIVE

We have examined whether abnormal calibration of intracellular signaling pathways renders acute coronary syndrome (ACS) patients susceptible to disproportionate T-cell responses.

METHODS AND RESULTS

Intracellular signaling cascades were quantified in CD4 T cells from ACS patients and control individuals after stimulation with major histocompatibility complex class II-superantigen complexes. ACS T cells mobilized more intracellular calcium and accumulated higher levels of phosphotyrosine than control T cells. Proximal steps in TCR signaling, such as recruitment of ZAP-70 and clustering of TCR complexes in the immune synapse, were abnormally enhanced in ACS T cells. Acceleration of the signaling cascade derived from a proximal defect in ACS T cells, which failed to phosphorylate Lck at Tyr505, extending activation of the Src kinase. Abnormalities in TCR signaling did not correlate with systemic inflammation as measured by C-reactive protein.

CONCLUSIONS

An intrinsic abnormality in the signaling machinery of ACS T cells resulting in the accumulation of active Lck lowers the TCR threshold and renders lymphocytes hyperreactive and capable of unwanted immune responses.

Urinary CD4+ effector memory T cells reflect renal disease activity in antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

Numbers of circulating CD4+ effector memory T cells are proportionally increased in patients with proteinase 3 antineutrophil cytoplasmic antibody-associated vasculitis (AAV) whose disease is in remission and are decreased during active disease, which presumably reflects their migration toward sites of inflammation. Since renal infiltrating cells may appear in urine, we investigated the presence of CD4+ effector memory T cells in urinary sediment as a reflection of renal disease activity in AAV.

METHODS

CD4+ effector memory (CD45RO+CCR7-CD3+CD4+) T cells were quantitated in the urine and peripheral blood of patients with AAV with renal involvement (n = 33), patients with AAV without renal involvement (n = 18), patients with AAV whose disease was in remission (n = 29), and patients with active disease (n = 22), using 4-color flow cytometric analysis. Numbers and percentages of urine CD4+ effector memory T cells in 12 patients with AAV with active renal disease were obtained over several weeks of followup during remission induction.

RESULTS

A notable increase in urine CD4+ effector memory T cell numbers was observed in patients with active renal AAV compared with patients whose disease was in remission and patients with active disease without renal involvement. The increase in these cells in the urine of patients with active renal AAV was accompanied by a reciprocal decrease in these cells in peripheral blood. Results from followup analysis showed a clear reduction in urine CD4+ effector memory T cells following treatment. Moreover, a negative correlation was observed between percentages of circulating and urine CD4+ effector memory T cells, consistent with their migration toward sites of inflammation.

CONCLUSION

Our findings indicate that the presence of CD4+ effector memory T cells in urine reflects renal involvement in AAV. Flow cytometric analysis of these cells in urine may contribute to assessing renal disease activity in patients with AAV.

Stimulatory and inhibitory killer Ig-like receptor molecules are expressed and functional on lupus T cells

T cells from lupus patients have hypomethylated DNA and overexpress genes normally suppressed by DNA methylation that contribute to disease pathogenesis. We found that stimulatory and inhibitory killer cell Ig-like receptor (KIR) genes are aberrantly overexpressed on experimentally demethylated T cells. We therefore asked if lupus T cells also overexpress KIR, and if the proteins are functional. T cells from lupus patients were found to overexpress KIR genes, and expression was proportional to disease activity. Abs to the stimulatory molecule KIR2DL4 triggered IFN-gamma release by lupus T cells, and production was proportional to disease activity. Similarly, cross-linking the inhibitory molecule KIR3DL1 prevented the autoreactive macrophage killing that characterizes lupus T cells. These results indicate that aberrant T cell KIR expression may contribute to IFN overproduction and macrophage killing in human lupus, and they suggest that Abs to inhibitory KIR may be a treatment for this disease.

Periodontal disease and risk of atherosclerotic coronary heart disease

Atherosclerosis is an important component of coronary heart disease (CHD), which is the leading cause of death worldwide, including in Japan. Because atherosclerotic processes are typified by chronic inflammatory responses, which are similar to those elicited by chronic infection, the role of infection in promoting or accelerating atherosclerosis has received considerable focus. Increasing evidence supports the notion that periodontitis is associated with increased risk of atherosclerosis through dysfunction of endothelial cells induced by either periodontopathic bacteria or their products, or inflammatory mediators derived from infected periodontal tissue. Here we review whether periodontitis represents a risk factor for CHD or atherosclerosis, particularly in a Japanese population.

Accelerated atherosclerosis in inflammatory rheumatic diseases

Over recent years it has become clear that patients with inflammatory rheumatic diseases are at increased risk of developing atherosclerosis. The exact causes for this are probably related in part to a general adverse effect of inflammation on atherogenesis, and in part to immune mechanisms specific to individual rheumatic diseases. This review discusses proposed mechanisms of accelerated atherosclerosis, including abnormal lipid and lipoprotein profiles, oxidative stress, enhanced apoptosis, thrombophilia, immune complexes, and increased mononuclear cell infiltration of atherosclerotic lesions, and local generation of cytokines.

CD28(-) T cells: their role in the age-associated decline of immune function

The accumulation of CD28(-) T cells, particularly within the CD8 subset, is one of the most prominent changes during T-cell homeostasis and function associated with aging in humans. CD28, a major co-stimulatory receptor, is responsible for the optimal antigen-mediated T-cell activation, proliferation and survival of T cells. CD28(-) T cells exhibit reduced antigen receptor diversity, defective antigen-induced proliferation and a shorter replicative lifespan while showing enhanced cytotoxicity and regulatory functions. Gene expression analyses reveal profound changes of CD28(-) T cells in comparison to their CD28(+) counterparts and corroborate their functional differences. Here we review recent advances in our understanding of CD28(-) T cells and their role in the age-associated decline of immune function.