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Biomedical subjects

Jörg J Goronzy

Publications and source records attributed to Jörg J Goronzy.

At least 19 recordsLinked to original sources
PubMed2007

Aging and T-cell diversity.

Naïve and memory CD4 and CD8 T cells constitute a highly dynamic system with constant homeostatic and antigen-driven proliferation, influx, and loss of T cells. Thymic activity dwindles with age and essentially ceases in the later decades of life, severely constraining the generation of new T cells. Homeostatic control mechanisms are very effective at maintaining a large and diverse subset of naïve CD4 T cells through the 7th decade of life, but eventually and abruptly fail at about the age of 75 years. In contrast, the CD8 T cell compartment is more unstable, with progressive diminution of naïve T cells and increasing loss of diversity during mid adulthood. Vaccination strategies need to aim at developing a broad repertoire of memory T cells before the critical time period when the naïve CD4 T-cell repertoire collapses. Research efforts need to aim at understanding T-cell homeostatic control mechanisms to ultimately expand the time period of repertoire stability.

Adult↗
PubMed2006

Functional profile of activated dendritic cells in unstable atherosclerotic plaque.

BACKGROUND: Unstable atherosclerotic plaque typically contains an infiltrate of activated macrophages and activated T cells. This study established a functional profile of plaque-residing dendritic cells (DC) to examine whether they can function as Ag-presenting cells to facilitate in situ T-cell activation. METHODS: Carotid artery plaque tissues were collected from 19 asymptomatic and 38 symptomatic patients undergoing endarterectomy. Matched samples of normal coronary artery wall, stable nonruptured plaque, and eroded unstable plaque were harvested from patients with fatal myocardial infarction. Quantitative PCR and immunohistochemistry were used to analyze the tissues for markers of DC activation (CD83, CD86, CCL19,CCL21) and correlate them with T-cell activation (IFN-gamma,TNF-alpha). RESULTS: Carotid artery plaques from patients with ischemic symptoms compared to asymptomatic patients were characterized by the presence of high amount of T-cells (P<0.01) and tissue production of high levels of the T-cell cytokines IFN-gamma (P=0.001) and TNF-alpha (P=0.006). Plaque tissues from patients with ischemic complications contained elevated levels of CD83 (P<0.001), a marker of DC activation, and the DC chemokines CCL19 (P=0.001) and CCL21 (P<0.02). Unstable coronary artery plaques were similarly correlated compared to carotid plaques from symptomatic patients with the accumulation of T cells (P=0.001) and the production of T cell chemokines IFN-gamma (P=0.001) and TNF-alpha (P=0.002). Immunohistochemistry confirmed the presence of CD83(+) DC in the shoulder region of unstable plaques, where they produced the T cell-attracting chemokines CCL19 and CCL21. Mapping of activated DC demonstrated close contact between mature DC and T cells expressing the activation marker CD40 ligand (CD40L). CONCLUSION: Activated and fully mature DC are represented in the inflammatory infiltrate characteristic for unstable carotid and coronary atheroma. Such DC produce chemokines, and thus can regulate the cell traffic into the lesion. Through the expression of the costimulatory ligand CD86, plaque-residing DC can augment T-cell stimulation and provide optimal stimulation conditions for T lymphocytes, resembling the microenvironment in organized lymphoid tissues.

Atherosclerosis↗
PubMed2006

Treatment of chronic inflammatory diseases with biologic agents: opportunities and risks for the elderly.

The treatment armamentarium in rheumatic inflammatory diseases has drastically increased in the last years. Earlier uses of conventional disease-modifying antirheumatic drugs (DMARDs), along with the arrival of newer therapies including the so-called "biologic" agents, have provided better long-term outcomes for patients suffering from these illnesses. Biologic agents have shown efficacy for several diseases and failed in others. Due to a high prevalence of some of these diseases in the elderly population, this age group may also benefit, although treatment will have to be tailored to its special needs. In this mini review, we will discuss the use of these medications in rheumatic diseases with a significant prevalence in the elderly, their proven and potential uses, and the considerations that need to be taken into account when using them in this population.

Aged↗
PubMed2006

Pathogen-sensing plasmacytoid dendritic cells stimulate cytotoxic T-cell function in the atherosclerotic plaque through interferon-alpha.

BACKGROUND: Unstable atherosclerotic plaque is characterized by an infiltrate of inflammatory cells. Both macrophages and T cells have been implicated in mediating the tissue injury leading to plaque rupture; however, signals regulating their activation remain unidentified. Infectious episodes have been suspected to render plaques vulnerable to rupture. We therefore explored whether plasmacytoid dendritic cells (pDCs) that specialize in sensing bacterial and viral products can regulate effector functions of plaque-residing T cells and thus connect host infection and plaque instability. METHODS AND RESULTS: pDCs were identified in 53% of carotid atheromas (n=30) in which they localized to the shoulder region and produced the potent immunoregulatory cytokine interferon (INF)-alpha. IFN-alpha transcript concentrations in atheroma tissues correlated strongly with plaque instability (P<0.0001). Plaque-residing pDCs responded to pathogen-derived motifs, CpG-containing oligodeoxynucleotides binding to toll-like receptor 9, with enhanced IFN-alpha transcription (P=0.03) and secretion (P=0.007). IFN-alpha emerged as a potent regulator of T-cell function, even in the absence of antigen recognition. Specifically, IFN-alpha induced a 10-fold increase of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the surface of CD4 T cells (P<0.0001) and enabled them to effectively kill vascular smooth muscle cells (P=0.0003). CONCLUSIONS: pDCs in atherosclerotic plaque sense microbial motifs and amplify cytolytic T-cell functions, thus providing a link between host-infectious episodes and acute immune-mediated complications of atherosclerosis.

Aged↗
PubMed2006

T cell recognition and killing of vascular smooth muscle cells in acute coronary syndrome.

Loss of vascular smooth muscle cells (VSMCs) has been proposed to destabilize the atherosclerotic plaque and contribute to plaque rupture, superimposed thrombosis, and acute coronary syndromes (ACSs). We examined whether VSMCs are susceptible to T cell-induced apoptosis and found that CD4 T cells are highly effective in establishing cell-cell contact with VSMCs and triggering apoptotic death. Visualization of the T cell-VSMC contact zone on the single-cell level revealed that both patient-derived and control CD4 T cells reorganized their cell membrane to assemble an immunologic synapse with the VSMCs. Within 4 to 10 minutes, the membrane proximal signaling molecule ZAP-70 was recruited and phosphorylated. However, only patient-derived CD4 T cells sustained an intact immunologic synapse beyond 10 minutes and generated intracellular calcium signals. CD4 T cells that maintained a synaptic contact and appeared to be responsible for VSMC apoptosis accounted for approximately 20% of the circulating memory T cell population in ACS patients and were rare in the blood of age-matched controls. CD4 T cells from ACS patients were also hyperresponsive to T cell receptor-mediated stimulation when triggered by a superantigen and non-VSMC target cells. Lowered setting of the T cell activation threshold, attributable to excessive amplification of proximal CD3-mediated signals, may contribute to CD4 T cell-mediated killing of VSMCs and promote plaque instability.

Acute Disease↗
PubMed2006

Uncoupling of T-cell effector functions by inhibitory killer immunoglobulin-like receptors.

Killer immunoglobulin-like receptors (KIRs) are a family of regulatory cell-surface molecules expressed on natural killer (NK) cells and memory T-cell subsets. Their ability to prevent the formation of an activation platform and to inhibit NK cell activation is the basis of the missing self model of NK cell function. The benefits of KIR expression for T-cell biology are unclear. We studied how KIR2DL2 regulates T-cell function. Engagement of KIR2DL2 by the ligand human leukocyte antigen (HLA)-Cw3 did not affect conjugate formation between CD4(+)KIR2DL2(+) T cells and superantigen-pulsed target cells or the development of mature immune synapses with lipid rafts. KIR2DL2 and the corresponding HLA-C ligand were initially recruited to the peripheral supramolecular activation cluster (pSMAC). Consequently, KIR2DL2 engagement did not inhibit the phosphorylation of early signaling proteins and T-cell-receptor (TCR)-mediated cytotoxicity or granule exocytosis. After 15-30 minutes, KIR2DL2 moved to the central supramolecular activation cluster (cSMAC), colocalizing with CD3. TCR synapses dissociated, and phosphorylated phospholipase C (PLC)-gamma1, Vav1, and extracellular signal-regulated kinase 1/2 (ERK1/2) were reduced 90 minutes after stimulation. Gene array studies documented that the inhibition of late signaling events by KIR2DL2 affected transcriptional gene activation. We propose that KIRs on memory T cells operate to uncouple effector functions by modifying the transcriptional profile while leaving granule exocytosis unabated.

CD4-Positive T-Lymphocytes↗
PubMed2006

Simvastatin suppresses endotoxin-induced upregulation of toll-like receptors 4 and 2 in vivo.

In addition to lipid lowering effects, statins appear to have pleiotropic immunomodulatory properties. As they particularly affect monocyte functions, we tested the influence of statin treatment on the monocyte activating toll-like receptors (TLR) 4 and 2 in response to lipopolysaccharides (LPS) in vivo. In this double-blind, placebo-controlled study, 20 healthy, male subjects were randomized to receive either simvastatin (80 mg/day) or placebo for 4 days before intravenous LPS administration (20 IU/kg). Simvastatin did not influence the increase in TLR transcripts after LPS administration measured in mRNA isolated from whole blood by quantitative RT-PCR. In contrast, the parallel upregulation of TLR4 and TLR2 on the surface of monocytes determined by flow cytometry was attenuated by more than half after LPS challenge (P<0.02). Suppressed TLR4 and TLR2 expression was associated with diminished circulating concentrations of tumor necrosis factor-alpha and monocyte chemoattractant protein-1. In conclusion, high-dose simvastatin pretreatment blunted TLR4 and TLR2 expression on monocytes in a human endotoxemia model on a posttranscriptional level. This suppressive effect of statins on key receptors of the innate immunity which was associated with a reduction of effector cytokines reveals a potential mechanism for their beneficial effects in sepsis and cardiovascular disease.

Adult↗
PubMed2006

Telomeres, immune aging and autoimmunity.

Telomere length is important in constraining the replicative potential of cells; cellular systems that are dependent on cell replenishment for renewal or on cell proliferation for functionality are highly sensitive to telomeric erosion. Cell replication invariably leads to telomere loss, which, in some cellular systems, is partially compensated for by telomerase activity. In addition to this typical telomere loss, several mechanisms of sporadic telomere loss exist. Heterogeneity in age-dependent telomere loss can be a consequence of increased cellular turnover during a lifetime, accelerated telomeric DNA damage, or defects in telomere repair. The immune system is a prime example of a highly dynamic cellular system, for which telomere maintenance is pivotal. Immune competence is strictly dependent on rapid expansions of clonal T- and B-cell populations, and telomere loss may contribute to defective immune responses in the elderly. Equally interestingly, accelerated T-cell aging combined with telomeric shortening may predispose for autoimmune responses and thereby explain the increased susceptibility for chronic inflammatory diseases in the elderly.

Aging↗
PubMed2006

Interleukin 12 induces T-cell recruitment into the atherosclerotic plaque.

CD4 T cells, through the release of cytokines as well as direct effector functions, have been implicated in promoting inflammation of the atherosclerotic plaque. Plaque-infiltrating CD4 T cells include a specialized subset of (CD4+)CD28- T cells that express a unique profile of regulatory receptors and are responsive to novel microenvironmental cues. Here we report that (CD4+)CD28- T cells, either isolated from the plaque tissue or from the blood of patients with acute coronary syndrome (ACS), spontaneously express interleukin (IL)-12 receptors, even in the absence of antigenic stimulation. (CD4+)CD28- IL-12R+ cells responded to IL-12 stimulation with the upregulation of the chemokine receptor CCR5 and the C-type lectin receptor CD161, both implicated in regulating tissue homing of effector T cells. IL-12 treatment of (CD4+)CD28- T cells enhanced their chemotaxis and transendothelial migration toward the chemokine CCL5. In vivo relevance for the role of IL-12 in regulating the recruitment of (CD4+)CD28- T cells into the atheroma was examined in human atheroma-SCID mouse chimeras. Exposure of nonstimulated (CD4+)CD28- T cells to IL-12 was sufficient to amplify T-cell accumulation within the inflamed plaque, and coadministration of anti-CCR5 antibodies blocked T-cell recruitment into the plaque. Thus, (CD4+)CD28- T cells functionally resemble NK cells, which have proinflammatory activity even in the unprimed state and respond to any IL-12-inducing host infection with a shift in tissue trafficking and accrual in inflammatory lesions.

Aged↗
PubMed2006

TRAIL-expressing T cells induce apoptosis of vascular smooth muscle cells in the atherosclerotic plaque.

Acute coronary syndromes (ACS) are precipitated by a rupture of the atherosclerotic plaque, often at the site of T cell and macrophage infiltration. Here, we show that plaque-infiltrating CD4 T cells effectively kill vascular smooth muscle cells (VSMC). VSMCs sensitive to T cell-mediated killing express the death receptor DR5 (TNF-related apoptosis-inducing ligand [TRAIL] receptor 2), and anti-TRAIL and anti-DR5 antibodies block T cell-mediated apoptosis. CD4 T cells that express TRAIL upon stimulation are expanded in patients with ACS and more effectively induce VSMC apoptosis. Adoptive transfer of plaque-derived CD4 T cells into immunodeficient mice that are engrafted with human atherosclerotic plaque results in apoptosis of VSMCs, which was prevented by coadministration of anti-TRAIL antibody. These data identify that the death pathway is triggered by TRAIL-producing CD4 T cells as a direct mechanism of VSMC apoptosis, a process which may lead to plaque destabilization.

Adoptive Transfer↗
PubMed2006

Association of HLA-C3 and smoking with vasculitis in patients with rheumatoid arthritis.

OBJECTIVE: To compare HLA-C genotypes and smoking habits in patients with vasculitis or other severe extraarticular manifestations of rheumatoid arthritis (ExRA) with those in RA patients without extraarticular disease. METHODS: Patients were recruited from a large research database of patients with RA at the Mayo Clinic, from 2 Swedish cohorts of prevalent RA cases, and from a regional Swedish early RA cohort. Patients with severe ExRA (n = 159) and control patients with RA but no history of ExRA (non-ExRA controls) (n = 178) were matched for duration of RA and for clinical center. Data on smoking at RA onset, rheumatoid factor (RF) status, and antinuclear antibodies (ANAs) were extracted from the medical records. Polymerase chain reaction-based HLA-C genotyping was performed using a sequence-specific primer kit. RESULTS: The distribution of HLA-C alleles was significantly different between patients with RA-associated vasculitis and non-ExRA controls (P = 0.014). This was mainly due to a positive association of the HLA-C3 allele with vasculitis (allele frequency 0.411 in vasculitis patients versus 0.199 in non-ExRA controls; P < 0.001) and a decreased frequency of HLA-C7 (0.122 and 0.243, respectively; P = 0.018). The association between HLA-C3 and vasculitis was not due to linkage disequilibrium with HLA-DRB1. Smoking (P = 0.001), RF positivity (P < 0.0001), and presence of ANAs (P < 0.0001) were all associated with ExRA. HLA-C3 and smoking were both significant predictors of vasculitis in a multivariate model. CONCLUSION: Vasculitis in RA is associated with HLA-C3. Smoking is an independent predictor of vasculitis and other types of severe ExRA. Our results suggest that these variables are among the genetic and environmental factors that contribute significantly to the pathomechanisms of systemic RA.

Adult↗
PubMed2006

Treatment of giant cell arteritis using induction therapy with high-dose glucocorticoids: a double-blind, placebo-controlled, randomized prospective clinical trial.

OBJECTIVE: Glucocorticoid (GC) therapy for giant cell arteritis (GCA) is effective but requires prolonged administration, resulting in adverse side effects. The goal of the current study was to test the hypothesis that induction treatment with high-dose pulse intravenous (IV) methylprednisolone permits a shorter course of therapy. METHODS: Twenty-seven patients with biopsy-proven GCA were enrolled in a randomized, double-blind, placebo-controlled study to receive IV methylprednisolone (15 mg/kg of ideal body weight/day) or IV saline for 3 consecutive days. All patients were started on 40 mg/day prednisone and followed the same tapering schedule as long as disease activity was controlled. The numbers of patients with disease in remission after 36, 52, and 78 weeks of treatment and taking <or=5 mg/day prednisone were compared. Cumulative prednisone dose, number of relapses, and development of adverse GC effects were assessed. RESULTS: Ten of the 14 IV GC-treated patients, but only 2 of 13 control patients, were taking <or=5 mg/day prednisone at 36 weeks (P = 0.003). This difference was maintained; there was a higher number of sustained remissions after discontinuation of treatment in the IV GC-treated group and a lower median daily dose of prednisone at 78 weeks (P = 0.0004). The median cumulative dose of oral prednisone, excluding the IV GC dose, was 5,636 mg in the IV GC-treated group compared with 7,860 mg in the IV saline-treated group (P = 0.001). CONCLUSION: Initial treatment of GCA with IV GC pulses allowed for more rapid tapering of oral GCs and had long-term benefits, with a higher frequency of patients experiencing sustained remission of their disease after discontinuation of treatment.

Administration, Oral↗
PubMed2006

T-cell-targeted therapies in rheumatoid arthritis.

T cells regulate the disease process in rheumatoid arthritis (RA) on multiple levels and represent a logical choice for anti-inflammatory therapy. In the inflamed joint they promote neoangiogenesis and lymphoid organogenesis, and stimulate synoviocyte proliferation and development of bone-eroding osteoclasts. The design of T-cell-targeted therapies for RA needs to take into account the uniqueness of T-cell generation, turnover and differentiation in affected patients. Patients accumulate 'old' T cells that respond to alternate regulatory signals because of an accelerated immune aging process; any therapeutic interventions that increase the replicative stress of T cells should, therefore, be avoided. Instead, therapeutic approaches that raise the threshold for T-cell activation are more promising. As a rule, antigen-derived signals synergize with co-stimulatory signals to stimulate T cells; such co-stimulatory signals are now targeted in novel immunosuppressive therapies. An example is abatacept (soluble cytotoxic-T-lymphocyte-associated protein 4-immunoglobulin), which binds with high affinity to CD80/CD86 and effectively suppresses inflammatory activity in RA. The therapeutic benefits gained by disrupting T-cell co-stimulation indicate that the pathogenesis of RA is driven by a more generalized abnormality in T-cell activation thresholds rather than a highly selective action of arthritogenic antigens.

Arthritis, Rheumatoid↗
PubMed2006

Pathomechanisms in rheumatoid arthritis--time for a string theory?

RA is a quintessential autoimmune disease with a growing number of cells, mediators, and pathways implicated in this tissue-injurious inflammation. Now Kuhn and colleagues have provided convincing evidence that autoantibodies reacting with citrullinated proteins, known for their sensitivity and specificity as biomarkers in RA, enhance tissue damage in collagen-induced arthritis (see the related article beginning on page 961). This study adds yet another soldier to the growing army of autoaggressive mechanisms that underlie RA. With great success researchers have dismantled the pathogenic subunits of RA, adding gene to gene, molecule to molecule, and pathway to pathway in an ever more complex scheme of dysfunction. The complexity of the emerging disease model leaves us speechless. It seems that with this wealth of data available, we need to develop a new theory for this disease. We may want to seek guidance from our colleagues in physics and mathematics who have successfully integrated their knowledge of elementary particles and the complexity of their interacting forces by formulating the string theory.

Animals↗
PubMed2005

BLyS and APRIL in rheumatoid arthritis.

The cytokines B lymphocyte stimulator (BLyS) and a proliferation-inducing ligand (APRIL) enhance autoimmune disease by sustaining B cell activation. In RA, B cells contribute to the formation of 3 functionally distinct types of lymphoid microarchitectures in the inflamed synovium: ectopic GCs; T cell-B cell aggregates lacking GC reactions; and unorganized, diffuse infiltrates. We examined 72 tissues representing the 3 types of synovitis for BLyS and APRIL production and for expression of APRIL/BLyS receptors. Biologic effects of BLyS and APRIL were explored by treating human synovium-SCID mouse chimeras with the APRIL and BLyS decoy receptor transmembrane activator and CAML interactor:Fc (TACI:Fc). GC+ synovitis had the highest levels of APRIL, produced exclusively by CD83+ DCs. BLyS was present in similar levels in all tissue types and derived exclusively from CD68+ macrophages. In GC+ synovitis, treatment with TACI:Fc resulted in GC destruction and marked inhibition of IFN-gamma and Ig transcription. In contrast, inhibition of APRIL and BLyS in aggregate and diffuse synovitis left Ig levels unaffected and enhanced IFN-gamma production. These differential immunomodulatory effects correlated with the presence of TACI+ T cells in aggregate and diffuse synovitis and their absence in GC+ synovitis. We propose that BLyS and APRIL regulate B cell as well as T cell function and have pro- and antiinflammatory activities in RA.

Adult↗
PubMed2005

The impact of HLA-DRB1 genes on extra-articular disease manifestations in rheumatoid arthritis.

The objective of this study was to examine HLA-DRB1 and HLA-DQB1 genotypes in patients with severe extra-articular rheumatoid arthritis (ExRA) and to compare them with the genotypes of rheumatoid arthritis (RA) patients without extra-articular manifestations. Patients with severe ExRA were recruited from a large research database of patients with RA, from two cohorts of prevalent RA cases, and from a regional multicenter early RA cohort. Cases with ExRA manifestations (n = 159) were classified according to predefined criteria. Controls (n = 178) with RA but no ExRA were selected from the same sources. Cases and controls were matched for duration of RA and for clinical center. PCR based HLA-DRB1 and HLA-DQB1 genotyping was performed using the Biotest SSP kit, with additional sequencing in order to distinguish DRB1*04 subtypes. Associations between alleles and disease phenotypes were tested using multiple simulations of random distributions of alleles. There was no difference in global distribution of HLA-DRB1 and HLA-DQB1 alleles between patients with ExRA and controls. DRB1*0401 (P = 0.003) and 0401/0401 homozygosity (P = 0.002) were more frequent in Felty's syndrome than in controls. The presence of two HLA-DRB1*04 alleles encoding the shared epitope (SE) was associated with ExRA (overall odds ratio 1.79, 95% confidence interval 1.04-3.08) and with rheumatoid vasculitis (odds ratio 2.44, 95% confidence interval 1.22-4.89). In this large sample of patients with ExRA, Felty's syndrome was the only manifestation that was clearly associated with HLA-DRB1*0401. Other ExRA manifestations were not associated with individual alleles but with DRB1*04 SE double dose genotypes. This confirms that SE genes contribute to RA disease severity and ExRA. Other genetic and environmental factors may have a more specific impact on individual ExRA manifestations.

Arthritis, Rheumatoid↗