Chronic Activation Of Immune System Research Articles

A Rare STXBP2 Mutation in Severe COVID-19 and Secondary Cytokine Storm Syndrome.

Background: Primary (familial) hemophagocytic lymphohistiocytosis (pHLH) is a potentially lethal syndrome of infancy, caused by genetic defects in natural killer (NK) cell and CD8 T cell cytotoxicity, leading to hyperinflammation, elevated cytokine levels, and a disorganized immune response resulting in multi-organ system failure and frequently death. Secondary HLH (sHLH) can be triggered in the setting of malignances, diseases of chronic immune system activation, or by infectious etiologies. While pHLH is usually a result of homozygous gene mutations, monoallelic hypomorphic and dominant-negative mutations in pHLH genes have been implicated in sHLH. Coronavirus disease 2019 (COVID-19) has been an omnipresent viral infection since its arrival, and severe cases can present with cytokine storm and have clinical features and laboratory findings consistent with sHLH. Herein, we report an adolescent with severe COVID-19, decreased NK cell function, and features of sHLH. Her genetic evaluation identified a monoallelic missense mutation in the pHLH gene STXBP2, and NK cell assays of her blood showed decreased cytolysis and degranulation ex vivo. Methods: Patient data was extracted through an electronic medical record review. Using a lentiviral approach, the patient’s STXBP2 mutation and wild-type (WT) STXBP2 were separately transduced into the NK-92 human NK cell line. The WT and mutant STXBP2 transduced NK-92 cells were stimulated with NK-sensitive K562 erythroleukemia target cells in vitro, and NK cell degranulation and cytolysis were measured via CD107a expression and Live/Dead near-IR dye, respectively. Results: Compared to WT STXBP2, the patient’s STXBP2 mutation caused significantly decreased NK cell cytolysis and associated degranulation in vitro. Conclusion: These findings add weight to the hypothesis that some severe cases of COVID-19 may be accompanied by sHLH and hyperinflammation, especially in the setting of heterozygous pHLH genetic mutations. This has implications both diagnostically and therapeutically for severe COVID-19.

Small Molecule TREX1 Inhibitors as Novel Immunotherapies

Mutations in the 3′ ‐> 5′ exonuclease TREX1 are associated with a spectrum of autoimmune phenotypes in humans and mice. In those affected, pathology is driven by persisting DNA which would normally be degraded by functional TREX1 enzyme. This undegraded DNA stimulates the nucleic acid sensing pathway, cGAS‐ STING, whose subsequent signaling generates a type‐I interferon response. This type‐I interferon response ultimately results in the chronic immune system activation typical of those affected. TREX1 and the cGAS‐ STING pathway have also been implicated in the tumor microenvironment, where TREX1 is believed to degrade tumor‐derived DNA destined to trigger cGAS‐STING signaling. If this tumor‐derived DNA is not degraded, the stimulated cGAS‐STING pathway promotes IFN‐dependent antitumor immunity. Consequently, small molecule stimulators of the cGAS‐STING pathway have shown promise as immunotherapies in animal models. Similarly, mice devoid of TREX1 exonuclease activity exhibit T‐cell dependent resistance to tumor growth. Collectively, these findings indicate that stimulation of the cGAS‐STING pathway activates the immune system, and that TREX1 inactivation represents a novel strategy for this purpose. Furthermore, they demonstrate the immunotherapy potential of such approaches. Thus, we hypothesize that small molecule inhibitors of TREX1 will activate the cGAS‐STING pathway. Studies described here identify small molecule inhibitors of TREX1, determine their mechanism of inhibition, and directly test the hypothesis that they can activate the cGAS‐STING pathway in murine cells. Findings from these studies will generate new structural insights into how TREX1 exonuclease activity may be affected, and have already identified several candidate chemotypes for development into novel immunotherapies.Support or Funding InformationThis work was supported by the NIH, NIAID, NIGMS, Lupus Research Alliance, Wake Forest Innovations, and a Sandy Lee Cowgill Memorial Scholarship.D18N mice display T‐cell dependent tumor resistance.5×106 H31ml tumor cells were injected subcutaneously into WT and D18N mice, and tumor volume and survival tracked daily. Data in ‘B’ are separate study from ‘A’. For each study, eight to 16 mice were examined in two to four independent experiments. (A) D18N mice have decreased tumor growth in a mouse tumor model. (B) D18N model tumor‐resistance is T‐cell dependent. WT and D18N were treated with αCD8, αCD4, or isotype‐control antibodies. Arrows indicate D18N mice without treatment, or with CD8+ / CD4+ T‐cell depletion.Figure 1

Methanol extracts of Basella alba leaves alleviate stress in rats

ObjectiveStress is becoming an unavoidable threat in recent times, there has been increasing interest by researchers in the use of naturally occurring biologically active compounds with medicinal value to cure body ailments. The present work was carried out to investigate the effect of methanol extract of Basella alba leaves on stress in Wistar rats (Rattus norvegicus). MethodsA total of 35 male rats were used in this study. They were grouped into seven groups of five rats each. Group 1 (normal control) was received 10 mL/kg normal saline. Group 2 contained restraint stress rats only. Group 3 contained forced swim stress rats only. Group 4 and 5 were treated with 60 mg/kg of B. alba extract (BAE) thereafter subjected to restraint and forced swim stresses respectively. Group 6 and 7 were treated with 120 mg/kg of BAE thereafter subjected to restraint and forced swim stresses respectively. Stress procedures were carried out at the end of first and third weeks. ResultsIn the stressed rats, there were significant increases (P < 0.05) in fasting blood glucose and white blood cell count while there were significant decreases in superoxide dismutase activity and glutathione concentration when compared to group 1. There were significant decreases (P < 0.05) in blood glucose and white blood cell count and significant increases in superoxide dismutase and glutathione concentrations in BAE treated rats when compared to group 2 and 3. Some of the significant differences were either dose or duration dependent. ConclusionIn conclusion, results from this research suggest that BAE alleviates hyperglycaemia, chronic activation of immune system and generation of free radicals due to stress in Wistar rats.

Impact of Immune System Activation and Vascular Impairment on Male and Female Sexual Dysfunction.

Male and female sexual dysfunction (SD) is considered a multifactorial condition. Numerous studies have shown the involvement of inflammatory processes in this pathological condition. Sexual intercourse requires healthy and functioning vessels to supply the pelvic region in both males and females, generating penile erection and clitoral and vaginal lubrication, respectively. Cardiovascular diseases and associated risk factors may contribute negatively to pelvic blood flow, possibly through immune system activation. The study aimed to address the correlation between vascular inflammation driven by immune system activation and SD in males and females. A literature review was performed to identify articles addressing male and female SD and vascular inflammation. Key words included "male and female sexual dysfunction," "vascular inflammation," "iliac and pudendal arteries dysfunction," "genitourinary tract," and "blood flow." Management of systemic and local inflammation may be a useful alternative to improve SD and reduce the risk of cardiovascular diseases in the future. Increased levels of cytokines and chemokines have been detected in humans and animals with hypertension, obesity, and diabetic conditions. Chronic activation of the innate immune system, especially by pathogen- or damage-associated molecular patterns, and metabolic-related disorders may act as triggers further contributing to an increased inflammatory condition. Due to the reduced size of vessels, SD and retinal vascular impairments have been shown to be predictive factors for cardiovascular diseases. Therefore, considering that blood flow to the genitalia is essential for sexual function, endothelial dysfunction and vascular remodeling, secondary to chronic immune system activation, may be implicated in male and female vasculogenic SD. Several conditions appear to play a role in SD. In the present review, we have identified a role for the immune system in generating vascular and tissue impairments contributing to erectile dysfunction and female SD. Calmasini FB, Klee N, Webb RC, etal. Impact of Immune System Activation and Vascular Impairment on Male and Female Sexual Dysfunction. Sex Med Rev 2019;7:604-613.

Traumagenics: At the intersect of childhood trauma, immunity and psychosis

Early childhood trauma, including physical, sexual or emotional abuse, neglect, harm or threat of harm, is associated with adulthood dysregulation of the immune system. Trauma can induce chronic immune system activation. Associations between a chronic pro-inflammatory state and schizophrenia are an enduring finding of psychiatry, with elevated cytokine concentrations correlated with psychotic symptom severity. Most importantly, persons with schizophrenia and a history of childhood trauma demonstrate increased cytokine levels. Specific types of childhood trauma can also differentially impact the expression of unique immune markers. This study tested the hypotheses that levels of adverse childhood experiences (ACEs) would be associated with levels of peripheral immune activity assessed by IL6, IFNG, CXCL10, IRF1, STAT1 and TLR4 mRNA expression, and that there would be an association between ACEs and psychosis along a continuum from non-clinical controls (NCC) to psychotic disorders such as schizophrenia. These hypotheses were tested in 20 schizophrenia, 20 NCC. We found correlations between ACEs scores and immune markers, specifically IL6. We also found a positive association between ACEs and positive symptoms. Childhood trauma, through its effects on IL6, may be a risk factor for schizophrenia.

The Central Role of Biometals Maintains Oxidative Balance in the Context of Metabolic and Neurodegenerative Disorders.

Traditionally, oxidative stress as a biological aspect is defined as an imbalance between the free radical generation and antioxidant capacity of living systems. The intracellular imbalance of ions, disturbance in membrane dynamics, hypoxic conditions, and dysregulation of gene expression are all molecular pathogenic mechanisms closely associated with oxidative stress and underpin systemic changes in the body. These also include aspects such as chronic immune system activation, the impairment of cellular structure renewal, and alterations in the character of the endocrine secretion of diverse tissues. All of these mentioned features are crucial for the correct function of the various tissue types in the body. In the present review, we summarize current knowledge about the common roots of metabolic and neurodegenerative disorders induced by oxidative stress. We discuss these common roots with regard to the way that (1) the respective metal ions are involved in the maintenance of oxidative balance and (2) the metabolic and signaling disturbances of the most important biometals, such as Mg2+, Zn2+, Se2+, Fe2+, or Cu2+, can be considered as the central connection point between the pathogenesis of both types of disorders and oxidative stress.

Intervention with VG1177, a MHC Class II Invariant Peptide Chain (CLIP) Antagonist, Restores Afferent Arteriolar Autoregulatory Behavior during Chronic 14 Day Lipopolysaccharide Treatment

Lipopolysaccharide (LPS) is a cell wall component of gram‐negative bacteria that is a known ligand for toll‐like receptor 4, which, in turn, activates the innate immune system. MHC Class II‐associated invariant peptide (CLIP) is critically linked to antigen processing, presentation, and adaptive immune system activation. Chronic immune system activation and inflammation are linked to blunted afferent arteriolar autoregulatory behavior and kidney injury. Previous work established that afferent arteriolar autoregulatory behavior is impaired following 7 days of LPS treatment by osmotic minipump, while simultaneous co‐treatment with VG1177 preserved autoregulatory capability. Accordingly, we postulated that competitive CLIP antagonist (VG177) treatment could rescue autoregulatory behavior impaired by chronic low‐dose LPS exposure. Osmotic minipumps were implanted (day 0) for infusion of LPS (0.01mg/kg/day) or saline (0.9% NaCl) for 14 days and then kidneys were harvested for juxtamedullary nephron studies. Three groups (n=6/group) were studied: saline, LPS, and LPS + VG1177. LPS + VG1177 group received LPS infusion from day 0 through day 14 and then daily VG1177 treatment (3mg/kg/day; i.p.) was added on LPS‐infusion days 7–14. Systolic blood pressures were similar in all three on day 14 (124 ± 1 mmHg, 124 ± 2 mmHg, and 125 ± 2 mmHg, respectively). Afferent arteriole autoregulatory behavior was assessed in these groups by increasing perfusion pressure from 65 to 170 mmHg in 15 mmHg increments. Starting diameters were similar across all three groups (15.1 ± 1.2 μm; 14.5 ± 1.1 μm and 14.7 ± 1.6 μm, respectively). When perfusion pressure was increased from 65 to 170 mmHg, arteriolar diameter in the saline group decreased by 25 ± 1% (P&lt;0.05; n=6), exhibiting normal pressure‐induced autoregulatory vasoconstriction. Afferent arteriolar diameters in LPS treated kidneys decreased by just 4.5 ± 2% over the same pressure range, indicating significant (P&lt;0.05 vs. saline) loss of autoregulatory behavior. In the LPS + VG1177 intervention group, afferent arteriolar diameter decreased by 15.2 ± 1% (P&lt;0.05 vs. LPS) over the same pressure range, signifying partial restoration of afferent arteriolar autoregulatory behavior. Plasma endotoxin was measured on day 14 by Pierce LAL chromogenic endotoxin quantitation kit in the saline, LPS, and LPS + VG1177 groups. Plasma endotoxin concentration in the saline group averaged 5.5 ± 0.6 EU/mL compared to 67.7 ± 10.4 EU/mL; (P&lt;0.05; n=6) in the 14 day LPS alone group. In 14 day LPS + 7 days of VG1177 intervention, plasma endotoxin concentration was significantly lower (29.8 ± 3.5 EU/mL; P&lt;0.05; n=6) compared with LPS alone. Collectively, these data support the hypothesis that CLIP antagonism with VG1177 restores afferent arteriolar autoregulatory behavior during chronic 14 day low dose LPS treatment and may reduce the plasma endotoxin load. CLIP antagonism may open novel therapeutic targets for inflammatory kidney disease.Support or Funding InformationThis study was funded by a Pre‐doctoral Fellowship from the AHA Greater Southeast Affiliate: 14PRE20460061 and NIH: DK44628, HL098135.

(303) Sex differences in the impact of the suboptimal American diet in rats: effects on behavior, physiology and recovery

Obesity is a major concern in today’s society. Obesity contributes to poor health outcomes and, we have shown, prolonged recovery from injury. Here we fed male and female rats our Suboptimal American Diet (SAD, 49% kcal from carbohydrates, 35.6% from fat, 15.4% from protein) over the course of 20 weeks. Mechanical and thermal sensitivity did not change over the course of the diet exposure. However, locomotor activity, blood glucose levels and percent body fat were elevated in the SAD-exposed groups, whereas bone mineral density was decreased. At 20 weeks of exposure, Complete Friend’s Adjuvant (CFA) was administered and sensitivity measured. Male SAD-fed animals took longer to recover, but not SAD-fed females. Following resolution of CFA-induced hypersensitivity, blood was analyzed. SAD-fed males showed higher levels of leptin and the pro-inflammatory cytokines TNFa, IL-1b and IL-6 when compared to male controls. In contrast, female SAD-fed animals showed elevated triglycerides and the following cytokines and chemokines: IL-10, IL-13, IL-4, CXCL1, TNFa, IFN-g and IL-6. The prevalence of T-cell mediated cytokines (IL-13, IL-4) found in female SAD-fed circulation, suggests different physiological processes at play. Finally, microglial activation in spinal cords of SAD-fed animals was elevated threefold (when compared to controls) in the absence of pain. Therefore, these data suggest that a poor-quality diet results in significant changes in behavior and physiology that may be due to chronic immune system activation. Furthermore, the physiological changes resulting from an American diet may differentially affect males and females. Currently we are investigating immune system activation in the brain to further characterize these diet-induced alterations.

Mood, food, and cognition

Food is not only necessary as a metabolic fuel for the body, it becomes more and more evident that there exists an association between food and brain functions like mood and cognition. Tryptophan represents a key element for brain functioning, because of its role as a precursor for production of neurotransmitter serotonin (5-hydroxytryptamine). In clinical conditions, which involve chronic immune system activation or under cytokine therapy, lower tryptophan levels because of high catabolism of tryptophan as indicated by the kynurenine to tryptophan ratio are common and often associate with depressive mood. Studies in the in vitro model of mitogen-stimulated peripheral blood mononuclear cells revealed that several phytocompounds, mainly antioxidants like polyphenols and vitamins, can interfere with inflammatory signaling cascades including tryptophan breakdown. If extrapolated to the in vivo situation, such compounds could increase blood and brain tryptophan availability for serotonin production. Although there is some in vivo evidence for the effect of such compounds, outcomes are hardly predictable and most likely depend on the individual's immunological state. Not only a diet rich in tryptophan but also a diet rich in antioxidants can have a positive impact on mood and cognition. This could be of special relevance for individuals who present with low grade inflammation conditions.

Abstract P056: MHC CLass II-associated Invariant Peptide (CLIP) Antagonism During Chronic Lipopolysaccharide Treatment Preserves Afferent Arteriolar Autoregulatory Behavior

Lipopolysaccharide (LPS) is a cell wall component of gram-negative bacteria that can activate toll-like receptor 4, which in turn, activates the innate immune system. Chronic immune system activation is linked to blunted afferent arteriolar autoregulatory behavior and kidney injury. MHC Class II-associated invariant peptide (CLIP) provides a critical step in antigen processing, presentation, and adaptive immune system activation. Accordingly, we postulated that treatment with a competitive CLIP antagonist (CAP) during chronic low-dose LPS exposure would preserve afferent arteriolar autoregulatory behavior. Rats were implanted with osmotic minipumps (day 0) for infusion of LPS (0.01mg/kg/day) or saline (0.9% NaCl; 0.5μl/hr) for 8 days and then the kidneys were harvested for juxtamedullary nephron studies. Four groups (n=6/group) were studied: Control, LPS, LPS + CAP and Sham + CAP. Both LPS + CAP and Sham + CAP groups were treated with CAP (3mg/kg/day; i.p.) on days 1-7. Autoregulatory behavior was assessed in these groups by increasing perfusion pressure in 15 mmHg increments from 65 to 170 mmHg. Starting baseline diameters were similar across the control (15.2 ± 1.2 μm), LPS (14.1 ± 1.0 μm), LPS + CAP (15.1 ± 1.0), and Sham + CAP (15.7 ± 0.6) groups. When perfusion pressure was increased from 65 to 170 mmHg, control and sham + CAP afferent arteriolar diameter decreased significantly by 26 ± 4% and 25 ± 2% (P&lt;0.05), respectively. In contrast, afferent diameters from LPS treated kidneys decreased by just 5 ± 2% over the same pressure range indicating impaired afferent arteriolar autoregulatory behavior. In LPS + CAP treated kidneys, afferent arteriolar diameter decreased by 17 ± 2% (P&lt;0.05) over the same pressure range signifying preservation of autoregulatory behavior. These data support the hypothesis that CLIP antagonism during chronic low dose LPS treatment preserves afferent arteriolar autoregulatory behavior. Inhibiting CLIP may open novel therapeutic targets for inflammatory kidney disease.

Abstract P054: Inhibition of Endosomal MyD88-dependent Signaling with Chloroquine Improves Endothelial Function and Lowers Blood Pressure in Spontaneously Hypertensive Rats

Uncontrolled inflammation and chronic immune system activation are common in hypertension. However, the exact mechanisms by which they occur are not well understood. Innate immune system recognition and response to damage-associated molecular patterns (DAMPs) is becoming an increasingly accepted mechanism. Mitochondrial DNA (mtDNA) is a DAMP that is recognized by Toll-like receptor (TLR)9 and is elevated in the circulation of spontaneously hypertensive rats (SHR). Therefore, we sought to determine the contribution of TLR9 in hypertension. We hypothesized that TLR9 inhibition with lysosomotropic agent chloroquine would improve endothelial function and lower blood pressure in SHR. We treated adult SHR and control Wistar-Kyoto rats (12 weeks old), as well as a group of young SHR (5 weeks old) with chloroquine (40 mg/kg/day, i.p.) for 21 days. Chloroquine lowered adult SHR blood pressure (Veh: 201±2 vs. CQ: 182±5 mmHg, p&lt;0.05) and inhibited cyclooxygenase-dependent contraction to acetylcholine (ACh) in isolated mesenteric resistance arteries (MRA) from adult SHR [%NE (ACh 1 μmol/L), Veh: -31±8 vs. CQ: 70±10, p&lt;0.05]. Chloroquine also inhibited co-localization of not only TLR9, but also TLR7 and TLR8 (MyD88-dependent endolysosomotropic TLRs) with MyD88 in adult SHR MRA, as well as expression of MyD88 in young SHR MRA. Finally, we observed that prophylactic treatment with chloroquine, during the critical pre-hypertensive stage, ameliorated the development of high blood pressure (Veh: 190±4 vs. CQ: 174±5 mmHg, p&lt;0.05) and components of the adaptive immune system (decreased aortic-derived CD45+ leukocytes, circulating CD3+ T lymphocytes, and expression of CD44 on circulating and aortic-derived CD3+ T lymphocytes) upon maturation to adulthood in SHR. In conclusion, endosomal MyD88-dependent signaling from TLR7, 8, and 9 contribute to high blood pressure, endothelial dysfunction, and recruitment of the adaptive immune system in SHR. These findings support the involvement of the innate immune system in the pathogenesis and maintenance of hypertension.

Abstract 069: Intrarenal Arteries Sense Mitochondrial N-formyl Peptides via Formyl Peptide Receptor in Wistar and Spontaneously Hypertensive Rats (shr)

It is well established that chronic immune system activation contributes to hypertension and kidney injury. Mitochondria carry hallmarks of their bacterial ancestry and thus have emerged as a significant source of inflammatogenic damage-associated molecular patterns (DAMPs). One of these hallmarks is that it still uses an N-formyl-methionyl-tRNA as an initiator of protein synthesis. Recently, we have observed that mitochondrial DAMPs are elevated in the circulation of SHR, and that mitochondrial N-formyl peptides (F-MIT) infusion in rats induces systemic inflammation and vascular dysfunction via formyl peptide receptor (FPR) activation. However, we do not know if FPR plays a role in kidney injury and hypertension. We hypothesized that F-MIT activate FPR and lead to intrarenal dysfunction in 12 week old male Wistar and SHR (n=4-8). Wistar rats were treated with F-MIT (0.02 mg/kg) or non-formylated peptide (control) for 6 h and intrarenal arteries (diameter &gt;100 μm) were isolated. To exclude systemic effects of F-MIT, intrarenal arteries were also isolated from control rats and treated ex vivo with 100 nM F-MIT or non-formylated peptide. F-MIT treatment in vivo increased intrarenal arteries FPR protein expression (2.3-fold vs. control) and decreased β-arrestin 2 (protein that internalizes FPR upon activation) and phosphorylation of endothelial nitric oxide synthase (4-fold vs. control). These results were reproduced in isolated arteries incubated with F-MIT or control for 6 h ex vivo. Similarly, in intrarenal arteries from untreated SHR, we found that FPR protein expression was higher (1.5-fold vs. Wistar Kyoto, WKY) and β-arrestin 2 protein expression was decreased (2-fold vs. WKY). Interestingly, although treatment with hydrochlorothiazide (10-55 mg/kg/day) and reserpine (0.6-4.5 mg/kg/day) for 7 weeks attenuated the increase in blood pressure in SHR, anti-hypertensive therapy did not change FPR and β-arrestin 2 protein expression. Additionally, it was observed that the co-localization of FPR and β-arrestin 2 was decreased in intrarenal arteries from SHR. Overall, these data suggest that intrarenal arteries sense F-MIT. Also, FPR activation parameters following F-MIT treatment of normotensive rats are similar to those observed in SHR.

Chronic Immune Activation is the Cause of AIDS: Implication of Treatment in the Developing World

Overwhelming number of evidence suggests that chronic immune system activation and dysregulation is responsible for progression into AIDS. Levels of activation markers on CD8+ and CD4+ T cells and other markers of activated immune response correlate with progression to AIDS. The uncontrolled inflammatory response has been associated with damage of lymphoid organs and the gastrointestinal mucosa; thus, further affecting T cell homeostasis and causing bacterial translocation, respectively. Immune system activation persists even after viral loads have been suppressed with antiretroviral therapy, which has been associated with increased morbidity and mortality of patients. On the other hand, natural primate hosts of SIV display very little immune activation and do not progress to AIDS. Several studies have been performed with immune suppressors and modifiers on HIV patients with varying degrees of success. The immune modifier that showed the most promise of being globally accessible and affordable HIV treatment is a probiotic. Probiotic treatment studies demonstrated safety and efficacy in maintaining T cell homeostasis of HIV-infected individuals. The probiotic also has the potential of being genetically manipulated to increase its effectiveness. An effective probiotic treatment for HIV infections has the potential of being grown locally in resource limited regions and by the users themselves; therefore, reducing cost of HIV treatment and prolonging the health of HIV-infected individuals.

Role of Helicobacter pylori infection in autoimmune systemic rheumatic diseases.

The relationship between infection and autoimmunity has been increasingly defined over the last 20 years. The systemic rheumatic diseases are characterized by dysregulation of the immune system resulting in a loss of tolerance to self-antigen. The exact etiology for the majority of these diseases is unknown; however, a complex combination of host and environmental factors are believed to play a pivotal role. Helicobacter pylori (H. pylori) is one of the most widely studied infectious agents proposed as agents triggering autoimmune response. The persistent presence of H. pylori in the gastric mucosa results in chronic immune system activation with ongoing cytokine signaling, infiltration of gastric mucosa by neutrophils, macrophages, lymphocytes, as well as production of antibodies and effector T-cells. Various mechanisms have been proposed in an attempt to explain the extra-intestinal manifestations of H. pylori infections. These include: molecular mimicry, endothelial cell damage, superantigens and microchimerism. I performed a systematic literature review using the keywords "rheumatoid arthritis", "Sjögren's syndrome", "systemic sclerosis", "systemic lupus erythematosus", "Helicobacter pylori" and "pathogenesis". A systematic literature search was carried out in MEDLINE; EMBASE; Cochrane Library and ACR/EULAR meeting abstracts. In systemic rheumatic diseases H. pylori infection prevalence alone should not be expected to provide sufficient evidence for or against a pathologic role in the disease. In this article I review studies examining the potential involvement of H. pylori infection in autoimmune systemic rheumatic diseases. Further studies of the immunological response to H. pylori and its role in the pathogenesis of systemic rheumatic diseases are warranted.

Physical activity as antioxidant and palliative beneficial option in human immunodeficiency virus infection

Human immunodeficiency virus (HIV) infection is characterized by chronic activation of immune system as a consequence of persistent circulating virus. Evidences for in vivo oxidative stress, as an imbalance between oxidant and antioxidant status, were reported to arise during infection evolution. The high active antiretroviral therapy (HAART) has impact on the decline of mortality and morbidity associated to HIV infection but clinical and basic evidences of toxicity are still reported. With increased longevity HAART is prolonged and due to resistance against antiretroviral therapy (ART) new aspects are developed in order to manage HIV infection. In this context, effective non-pharmacological measures, such as regular physical activity have been used. Updates on research confirm that physical activity could mitigate the deleterious oxidative damage by stimulating resistance to oxidative challenge. This paper briefly reviews the wide pathophysiological pathways related to HIV infection, oxidative stress and immune dysfunction and then discusses in detail the benefits of training schedule for infected HIV infected individuals. This constitutes a complementary strategy promoting beneficial pleiotropic effects.

A systematic literature review examining soluble and cellular biomarkers in HIV patients receiving antiretroviral therapy

The use of antiretroviral therapies (ART) for treatment of human immunodeficiency virus type 1 (HIV‐1) has led to more favorable prognoses for infected individuals, including reduced HIV viral load, improved CD4 + T‐cell recovery, and slower disease progression. However, ART‐treated HIV+patients may have increased risk of adverse outcomes associated with chronic inflammation and immune activation. Molecules associated with chronic immune system activation and inflammatory cytokine production may be useful biomarkers of HIV pathogenesis and/or ART outcomes. We systematically identified MEDLINE‐indexed articles published in the past decade investigating the association of several soluble (IL‐6, CRP, MCP‐1, IP‐10, D‐dimer, soluble CD14, and LPS) and cellular (CD28, CD38, HLA‐DR, PD‐1, caspase‐3, IFNγ and IL‐2 ELISpots) biomarkers with clinical outcomes in ART‐treated HIV positive (HIV+) patients. Seventy publications were included, consisting mainly of observational studies of soluble biomarkers. One quartile elevations in baseline IL‐6, CRP, and D‐dimer were associated with increased risk of disease progression or death (ORs 1.8–2.4; p≤0.01) and all‐cause mortality (ORs 4.1–5.3; p≤0.0001); these elevations were also associated with increased rates of IRIS (ORs 1.59–2.07; p≤0.001). Additionally, IL‐6, CRP, and D‐dimer levels were higher in patients who experienced a cardiovascular event than in controls (p≤0.001). The association between soluble biomarkers and quantitative assessments of HIV viral load has not been studied as thoroughly. However, several studies found an association between D‐dimer and viral load. Research is lacking regarding the relationship between CD4 count and soluble biomarkers. Most studies evaluating cellular biomarkers examined their association with HIV viral load and CD4 count, but did not examine clinical outcomes. The most commonly studied cellular biomarkers were the T cell activation markers CD38 and HLA‐DR. Studies suggest that CD4 and CD8 activation were increased in patients with higher HIV viral load, and that CD8 activation was higher in patients with low CD4 counts. In our review, we found that several soluble biomarkers were related to the risk of adverse clinical outcomes in ART‐treated HIV+patients. More data, particularly regarding cell‐associated biomarkers, is required to characterize their association with outcomes of interest, to describe causality, and to document their prognostic importance.

Abstract 253: Sustained Activation of Toll-like Receptor 9 Increases Phenylephrine-Induced Contractions in Rat Mesenteric Resistance Arteries

Activation of Toll-like receptor 9 (TLR9) via bacterial or mitochondrial DNA induces systemic inflammation and is associated with heart failure and preeclampsia. TLR9 is expressed in the vasculature; however, whether activation of TLR9 affects vascular function is unknown. We hypothesized that sustained activation of TLR9 would increase rat mesenteric artery contractility. To test this hypothesis, female rats (16 weeks old) were injected intraperitoneally with a TLR9 agonist (ODN 2395, 0.1 μg/rat/day) or vehicle (saline) on 3 consecutive days and contractile responses to a thromboxane A 2 analog (U46619, 10 -9 -10 -5 M), potassium chloride (KCl, 10-80 mM), and phenylephrine (PE, 10 -9 -3x10 -5 M), in the presence and absence of a nitric oxide synthase inhibitor (LNNA, 10 -4 M) were measured in aortic and mesenteric rings from ODN- and vehicle-treated rats using a myograph. PE-induced contractions were increased in mesenteric but not in aortas from ODN-treated animals compared to vehicle group [E max (% max KCl), ODN-treated: 167±10 vs. Vehicle-treated: 113±13, (Fig. 1A)] and the magnitude of this difference remained unaltered following NOS inhibition (Fig. 1B). ODN 2395 treatment had no effect on vascular responses to U46619 or KCl in either mesenteric or aortic rings. In summary, in vivo TLR9 activation increases vascular contractility and this effect is vascular bed- and agonist-specific. We propose that chronic immune system activation due to multiple bacterial infections or accumulation of mitochondrial DNA increases vascular contractility via TLR9 signaling pathways leading to vascular dysfunction and contributing to the development of vascular disease.

Premature senescence of circulating T cells in HCV-chronically infected patients (105.41)

Abstract Persistent HCV infection is characterized by chronic immune system activation and inflammatory cytokine production. Thus, HCV infection may result in features characteristic of premature aging of immune cells (immune senescence), driven by chronic antigen exposure and immune system activation. To determine if untreated HCV infection is associated with premature aging of naïve and memory CD4+ and CD8+ T cells, peripheral blood mononuclear cells (PBMCs) from 24 individuals chronically infected with HCV and 13 healthy blood donors were stained with fluorochrome-conjugated antibodies, and then subjected to multiple-color flow cytometric analysis. We found that chronic HCV infection was associated with a decreased CD28 median florescence intensity on both CD4+ (CD3+/CD4+/CD45RA+CD27+CD28+) and CD8+ (CD3+/CD8+/CD45RA+CD27+CD28+) T cells. An increased proportion of intermediate- and late-differentiated CD4+ and CD8+ T cells was also observed in PBMCs from HCV chronically-infected individuals. In addition, higher levels of activated monocytes (CD14+/CD16+ or CD14+/CD69+) were detected in HCV chronically-infected individuals than that in healthy blood donors. Conclusions: The overall change during chronic HCV infection is associated with a shift in the T-cell population toward an aged confirmation. Our data suggest that HCV-infected individuals experience similar immunologic changes as the individuals infected with HIV-1.

Study of biomaterial-induced macrophage activation, cell-mediated immune response and molecular oxidative damage in patients with dermal bioimplants

Several soft-tissue dermal fillers have been reported to provoke immunogenicity and may cause adverse reactions despite claims regarding their safety. This study aimed to assess biomaterial-induced macrophage activation, cell-mediated immune response and oxidative stress in 169 patients with dermal bioimplants. To this end, we analysed plasma concentrations of myeloperoxidase (MPO), the chitinase-like proteins chitotriosidase and YKL-40 and molecular oxidative damage. The present study shows, for the first time, that the components of innate immunity: chitotriosidase and YKL-40, are significantly higher in patients with certain bioimplants and these markers of monocyte/macrophage activation rose progressively as adverse reactions (AR) evolved. Plasma MPO levels increased 4-fold in filler users with AR and 3-fold in those without. Analysis by filler type showed subjects injected with calcium hydroxylapatite, methacrylate, acrylamides and silicone to have values significantly above those of non-filler subjects for at least two plasma biomarkers, probably because the afore-mentioned biomaterials are permanent and prone to trigger AR in the long term. By contrast, hyaluronic acid alone elicited little immune response. Plasma concentrations of markers of oxidative damage to lipids and proteins were found to be significantly higher in users of four of the nine dermal fillers studied. These diffusible products of molecular peroxidation would stem from the reaction catalysed by MPO that generates potent oxidants, leading to cell oxidative damage which, in turn, may exert deleterious effects on the organism. Overall, the results of this study on the effects of a range of dermal fillers point to chronic activation of the immune response mediated by macrophages and PMNs. The increases in plasma of MPO, chitotriosidase and YKL-40 proteins and products of macromolecular peroxidation suggests that these molecules could serve as blood-based biochemical markers and alert to the risk of chronic immune system activation and development of adverse events that may arise from the use of certain bioimplants.

Biomarkers of immune dysfunction in HIV

HIV infection is characterized by chronic immune system activation and inflammatory cytokine production. This review will highlight recent developments using plasma and cellular biomarkers of immune system activation and dysfunction to predict mortality and opportunistic disease in HIV-infected individuals. HIV infection results in features characteristic of early aging of the immune system or 'immune senescence', driven by chronic antigen exposure and immune system activation. Microbial translocation of gut bacterial components is associated with chronic immune activation and possibly systemic inflammation. Antiretroviral therapy may not fully normalize this condition. Baseline elevations of certain biomarkers of inflammation or coagulopathy, notably interleukin-6 (IL-6), C-reactive protein (CRP), and D-dimer, have been associated with mortality or opportunistic disease, after adjustment for appropriate variables, in several large randomized clinical trials. It is not known if elevated IL-6 or CRP causes this morbidity and mortality or if they are simply surrogate markers of a global inflammatory state. Several inflammatory biomarkers appear to add to our ability to predict mortality or opportunistic disease in HIV-infected individuals. Before biomarkers will be useful, it will be necessary to identify interventions that moderate biomarker levels, and then determine if this moderation attenuates disease outcomes.