Removal of innate immune barriers allows efficient transduction of quiescent human hematopoietic stem cells.

Quiescent human hematopoietic stem cells (HSC) are ideal targets for gene therapy applications due to their preserved stemness and repopulation capacities; however, they have not been exploited extensively because of their resistance to genetic manipulation. We report here the development of a lentiviral transduction protocol that overcomes this resistance in long-term repopulating quiescent HSC, allowing their efficient genetic manipulation. Mechanistically, lentiviral vector transduction of quiescent HSC was found to be restricted at the level of vector entry and by limited pyrimidine pools. These restrictions were overcome by the combined addition of cyclosporin H (CsH) and deoxynucleosides (dNs) during lentiviral vector transduction. Clinically relevant transduction levels were paired with higher polyclonal engraftment of long-term repopulating HSC as compared with standard ex vivo cultured controls. These findings identify the cell-intrinsic barriers that restrict the transduction of quiescent HSC and provide a means to overcome them, paving the way for the genetic engineering of unstimulated HSC.

Interferon-inducible phospholipids govern IFITM3-dependent endosomal antiviral immunity.

The interferon-induced transmembrane proteins (IFITM) are implicated in several biological processes, including antiviral defense, but their modes of action remain debated. Here, taking advantage of pseudotyped viral entry assays and replicating viruses, we uncover the requirement of host co-factors for endosomal antiviral inhibition through high-throughput proteomics and lipidomics in cellular models of IFITM restriction. Unlike plasma membrane (PM)-localized IFITM restriction that targets infectious SARS-CoV2 and other PM-fusing viral envelopes, inhibition of endosomal viral entry depends on lysines within the conserved IFITM intracellular loop. These residues recruit Phosphatidylinositol 3,4,5-trisphosphate (PIP3) that we show here to be required for endosomal IFITM activity. We identify PIP3 as an interferon-inducible phospholipid that acts as a rheostat for endosomal antiviral immunity. PIP3 levels correlated with the potency of endosomal IFITM restriction and exogenous PIP3 enhanced inhibition of endocytic viruses, including the recent SARS-CoV2 Omicron variant. Together, our results identify PIP3 as a critical regulator of endosomal IFITM restriction linking it to the Pi3K/Akt/mTORC pathway and elucidate cell-compartment-specific antiviral mechanisms with potential relevance for the development of broadly acting antiviral strategies.

D-mannose suppresses macrophage IL-1ß production.

D-mannose is a monosaccharide approximately a hundred times less abundant than glucose in human blood. Previous studies demonstrated that supraphysiological levels of D-mannose inhibit tumour growth and stimulate regulatory T cell differentiation. It is not known whether D-mannose metabolism affects the function of non-proliferative cells, such as inflammatory macrophages. Here, we show that D-mannose suppresses LPS-induced macrophage activation by impairing IL-1ß production. In vivo, mannose administration improves survival in a mouse model of LPS-induced endotoxemia as well as decreases progression in a mouse model of DSS-induced colitis. Phosphomannose isomerase controls response of LPS-activated macrophages to D-mannose, which impairs glucose metabolism by raising intracellular mannose-6-phosphate levels. Such alterations result in the suppression of succinate-mediated HIF-1α activation, imposing a consequent reduction of LPS-induced Il1b expression. Disclosing an unrecognized metabolic hijack of macrophage activation, our study points towards safe D-mannose utilization as an effective intervention against inflammatory conditions.

Laboratory-Scale Lentiviral Vector Production and Purification for Enhanced Ex Vivo and In Vivo Genetic Engineering.

Lentiviral vectors (LVs) are increasingly employed in gene and cell therapy. Standard laboratory production of LVs is not easily scalable, and research-grade LVs often contain contaminants that can interfere with downstream applications. Moreover, purified LV production pipelines have been developed mainly for costly, large-scale, clinical-grade settings. Therefore, a standardized and cost-effective process is still needed to obtain efficient, reproducible, and properly executed experimental studies and preclinical development of ex vivo and in vivo gene therapies, as high infectivity and limited adverse reactions are important factors potentially influencing experimental outcomes also in preclinical settings. We describe here an optimized laboratory-scale workflow whereby an LV-containing supernatant is purified and concentrated by sequential chromatographic steps, obtaining biologically active LVs with an infectious titer and specific activity in the order of 109 transducing unit (TU)/mL and 5 × 104 TU/ng of HIV Gag p24, respectively. The purification workflow removes >99% of the starting plasmid, DNA, and protein impurities, resulting in higher gene transfer and editing efficiency in severe combined immunodeficiency (SCID)-repopulating hematopoietic stem and progenitor cells (HSPCs) ex vivo, as well as reduced activation of inflammatory responses ex vivo and in vivo as compared to TU-matched, laboratory-grade vectors. Our results highlight the value of accessible purified LV production for experimental studies and preclinical testing.

Assessing the Impact of Cyclosporin A on Lentiviral Transduction and Preservation of Human Hematopoietic Stem Cells in Clinically Relevant Ex Vivo Gene Therapy Settings.

Improving hematopoietic stem and progenitor cell (HSPC) permissiveness to lentiviral vector (LV) transduction without compromising their biological properties remains critical for broad-range implementation of gene therapy as a treatment option for several inherited diseases. This study demonstrates that the use of one-hit ex vivo LV transduction protocols based on either cyclosporin A (CsA) or rapamycin enable as efficient gene transfer as the current two-hit clinical standard into bone marrow-derived CD34+ cells while better preserving their engraftment capacity in vivo. CsA was additive with another enhancer of transduction, prostaglandin E2, suggesting that tailored enhancer combinations may be applied to overcome multiple blocks to transduction simultaneously in HSPC. Interestingly, besides enhancing LV transduction, CsA also significantly reduced HSPC proliferation, preserving the quiescent G0 fraction and the more primitive multipotent progenitors, thereby yielding the highest engraftment levels in vivo. Importantly, no alterations in the vector integration profiles could be detected between CsA and control transduced HSPC. Overall, the present findings contribute to the development of more efficient and sustainable LV gene therapy protocols, underscoring the benefits of scaling down required vector doses, as well as shortening the HSPC ex vivo culture time.

Cyclosporine H Overcomes Innate Immune Restrictions to Improve Lentiviral Transduction and Gene Editing In Human Hematopoietic Stem Cells.

Innate immune factors may restrict hematopoietic stem cell (HSC) genetic engineering and contribute to broad individual variability in gene therapy outcomes. Here, we show that HSCs harbor an early, constitutively active innate immune block to lentiviral transduction that can be efficiently overcome by cyclosporine H (CsH). CsH potently enhances gene transfer and editing in human long-term repopulating HSCs by inhibiting interferon-induced transmembrane protein 3 (IFITM3), which potently restricts VSV glycoprotein-mediated vector entry. Importantly, individual variability in endogenous IFITM3 levels correlated with permissiveness of HSCs to lentiviral transduction, suggesting that CsH treatment will be useful for improving ex vivo gene therapy and standardizing HSC transduction across patients. Overall, our work unravels the involvement of innate pathogen recognition molecules in immune blocks to gene correction in primary human HSCs and highlights how these roadblocks can be overcome to develop innovative cell and gene therapies.

Lentiviral vectors escape innate sensing but trigger p53 in human hematopoietic stem and progenitor cells.

Clinical application of lentiviral vector (LV)-based hematopoietic stem and progenitor cells (HSPC) gene therapy is rapidly becoming a reality. Nevertheless, LV-mediated signaling and its potential functional consequences on HSPC biology remain poorly understood. We unravel here a remarkably limited impact of LV on the HSPC transcriptional landscape. LV escaped innate immune sensing that instead led to robust IFN responses upon transduction with a gamma-retroviral vector. However, reverse-transcribed LV DNA did trigger p53 signaling, activated also by non-integrating Adeno-associated vector, ultimately leading to lower cell recovery ex vivo and engraftment in vivo These effects were more pronounced in the short-term repopulating cells while long-term HSC frequencies remained unaffected. Blocking LV-induced signaling partially rescued both apoptosis and engraftment, highlighting a novel strategy to further dampen the impact of ex vivo gene transfer on HSPC. Overall, our results shed light on viral vector sensing in HSPC and provide critical insight for the development of more stealth gene therapy strategies.

Pentraxin 3 plasma levels at graft-versus-host disease onset predict disease severity and response to therapy in children given haematopoietic stem cell transplantation.

Acute Graft-versus-Host Disease (GvHD) remains a major complication of allogeneic haematopoietic stem cell transplantation, with a significant proportion of patients failing to respond to first-line systemic corticosteroids. Reliable biomarkers predicting disease severity and response to treatment are warranted to improve its management. Thus, we sought to determine whether pentraxin 3 (PTX3), an acute-phase protein produced locally at the site of inflammation, could represent a novel acute GvHD biomarker. Using a murine model of the disease, we found increased PTX3 plasma levels after irradiation and at GvHD onset. Similarly, plasma PTX3 was enhanced in 115 pediatric patients on day of transplantation, likely due to conditioning, and at GvHD onset in patients experiencing clinical symptoms of the disease. PTX3 was also found increased in skin and colon biopsies from patients with active disease. Furthermore, PTX3 plasma levels at GvHD onset were predictive of disease outcome since they resulted significantly higher in both severe and therapy-unresponsive patients. Multiple injections of rhPTX3 in the murine model of GvHD did not influence the disease course. Taken together, our results indicate that PTX3 constitutes a biomarker of GvHD severity and therapy response useful to tailor treatment intensity according to early risk-stratification of GvHD patients.

Pentraxin-3 in chronic heart failure: the CORONA and GISSI-HF trials.

AIMS: Pentraxin-3 (PTX3) is a component of the humoral arm of innate immunity which can regulate inflammatory processes. Since the role of inflammation in the progression of chronic heart failure (HF) is debated, we investigated the prognostic value of PTX3 and the effect of a statin in two large populations of patients with HF. METHODS AND RESULTS: Plasma levels of PTX3 were measured at randomization and after 3 months in 1457 patients enrolled in the Controlled Rosuvastatin Multinational Trial in HF (CORONA) and 1233 patients enrolled in the GISSI-Heart Failure trial (GISSI-HF). The relationships between baseline PTX3 levels or their changes over time and mortality were evaluated with multivariable Cox proportional hazard models including clinical factors, high sensitivity C-reactive protein (hsCRP), and N-terminal pro brain natriuretic peptide (NT-proBNP). PTX3 concentration [median (Q1-Q3) = 5.34 (3.55-7.64) ng/mL, n = 2690] was higher in females, in older patients, and those with lower body mass index. Baseline elevated PTX3 was associated with a higher risk of all-cause mortality [759 events, hazard ratio (HR) for 1 SD increase 1.20, 95% confidence interval (CI) 1.12-1.30, P < 0.0001], cardiovascular mortality (587 events, HR 1.27, 95% CI 1.17-1.38, P < 0.0001), or hospitalization for worsening HF (720 events, HR 1.21, 95% CI 1.12-1.30, P < 0.0001), and marginally improved discrimination. Three-month changes in PTX3 were associated with fatal events after adjustment for hsCRP or NT-proBNP. Rosuvastatin lowered hsCRP levels but significantly raised PTX3. CONCLUSION: In two independent clinical trials that enrolled patients with chronic HF, PTX3 was consistently associated with outcomes. The opposite effects of a statin on hsCRP and PTX3 call for further investigation. TRIAL REGISTRATION: NCT00336336 (GISSI-HF), NCT00206310 (CORONA).

Pentraxin-3 as a marker of advanced atherosclerosis results from the Bruneck, ARMY and ARFY Studies.

OBJECTIVE: Pentraxins like C-reactive protein are key components of the innate immune system. Recently, pentraxin-3 (PTX3) has been proposed to be a specific marker of vascular inflammation, yet its association with atherosclerosis is still unclear. METHODS AND RESULTS: PTX3 serum levels were measured in three independent studies of 132 young men (ARMY Study), 205 young women (ARFY Study) and 562 individuals 55 to 94 years old (Bruneck Study). In contrast to C-reactive protein, PTX3 showed little relationships with classic vascular risk factors and pro-inflammatory conditions. In the population based Bruneck Study, PTX3 level was independently associated with prevalent cardiovascular diseases (multivariable odds ratio [95%CI] 3.09 [1.65-5.79]; P<0.001). Moreover, PTX3 level correlated with the severity of carotid and femoral atherosclerosis and was highest in individuals with multiple vascular territories affected. In contrast, there was no association with elevated intima-media thickness, a precursor lesion of atherosclerosis, in any of the three populations investigated. CONCLUSIONS: Level of PTX3 is independently associated with atherosclerosis and manifest cardiovascular disease but not early vessel pathology. Unlike C-reactive protein, PTX3 is not a component of the classic acute phase response (systemic inflammation) but appears to be more specific for vascular inflammation.

Pentraxin-3 predicts functional recovery and 1-year major adverse cardiovascular events after rehabilitation of cardiac surgery patients.

BACKGROUND: Inflammatory and vascular markers have proved to be predictors of outcome in myocardial infarction and heart failure. We evaluated several circulating markers of cardiac stress, inflammation, and endothelial function to investigate their ability to predict short-term functional recovery and long-term clinical outcome in heart surgery patients undergoing inpatient rehabilitation. METHODS: This prospective, multicenter study enrolled 223 patients after heart surgery, included in a 3-week program of standardized and supervised physical training. The association between biomarkers (pentraxin-3 [PTX3], brain natriuretic peptide, high-sensitivity cardiac troponin-T [hs-cTnT] and C-reactive protein [hsCRP], creatine kinase, myoglobin, and urinary albumin excretion [UACR]) and exercise capacity (6-minute walk test, 6MWT) or 1-year incidence of major adverse cardiovascular events (MACE) was tested in models that included biohumoral markers, and clinical and instrumental variables. RESULTS: The patients (69.5% men, mean age of 67 ± 11 years) were enrolled after valvular surgery (52.7%) and 58.6% after coronary artery bypass grafting (CABG). Exercise capacity improved during rehabilitation (6MWT distance from 279 ± 95 to 386 ± 91 m; P < .0001); concentrations of most biomarkers decreased (hsCRP: 79% [P < .0001]; hs-cTnT: 57% [P < .0001]; UACR: 36% [P = .05]). Among the tested markers, PTX3 showed the closest association with 6MWT distance (P = .01) and was the only predictor of MACE, also in the subgroup of CABG patients (OR [95% CI] = 1.14 [1.03-1.27]; P = .015). CONCLUSION: PTX3, a marker of vascular inflammation and cardiovascular damage, is a predictor of short-term functional recovery and 1-year MACE in patients undergoing rehabilitation after cardiac surgery, regardless of clinical and instrumental parameters.

Selective up-regulation of the soluble pattern-recognition receptor pentraxin 3 and of vascular endothelial growth factor in giant cell arteritis: relevance for recent optic nerve ischemia.

OBJECTIVE: To assess local expression and plasma levels of pentraxin 3 (PTX3) in patients with giant cell arteritis (GCA). METHODS: Plasma and serum samples were obtained from 75 patients with GCA (20 of whom had experienced optic nerve ischemia in the previous 3 weeks and 24 of whom had experienced symptom onset in the previous 6 months and had no history of optic nerve ischemia) and 63 controls (35 age-matched healthy subjects, 15 patients with rheumatoid arthritis, and 13 patients with chronic stable angina). In 9 patients in whom GCA was recently diagnosed, circulating levels of interleukin-1ß (IL-1ß), IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12p70, CCL2/monocyte chemotactic protein 1, CCL3/macrophage inflammatory protein 1α (MIP-1α), CCL4/MIP-1ß, CCL11/eotaxin, CXCL9/monokine induced by interferon-γ, CXCL10/interferon-γ-inducible 10-kd protein, tumor necrosis factor α (TNFα), interferon-γ, vascular endothelial growth factor (VEGF), granulocyte-macrophage colony-stimulating factor, and FasL were measured via a multiplexed cytometric assay. PTX3 and VEGF concentrations were assessed by enzyme-linked immunosorbent assay. PTX3 and CD68 expression were determined by immunohistochemistry and immunofluorescence on temporal artery samples. RESULTS: GCA patients with very recent optic nerve ischemia had significantly higher PTX3 and VEGF levels compared to other GCA patients and controls. GCA patients with a disease duration of <6 months had significantly higher PTX3 levels compared to other GCA patients and controls. Immunohistochemistry revealed selective PTX3 expression in the wall of inflamed arteries. CONCLUSION: Our findings indicate that local expression of PTX3 is a feature of vascular inflammation in GCA; elevated circulating levels of PTX3 identify patients with very recent optic nerve ischemia or a recent diagnosis. Optic nerve ischemia is also associated with increased circulating VEGF levels.

Plasma pentraxin-3 as a marker of bioincompatibility in hemodialysis patients.

INTRODUCTION: Hemodialysis (HD)-induced inflammation has a pathogenetic role in patients with end-stage renal disease (ESRD). The aim of the present study was to assess whether pentraxin-3 (PTX3) could be a reliable biomarker of HD-induced inflammation and of membrane biocompatibility. METHODS: We prospectively enrolled 31 HD patients. Blood samples for determining PTX3, C-reactive protein (CRP), leukocytes and neutrophils were drawn from the arterial needle, before dialysis after the long dialysis-free interval (time 0), at the end of the index session (time 1) and before the next dialysis session (time 2). In 22 of 31 patients, 30 minutes after start of dialysis, PTX3 and CRP plasma levels were measured in blood collected from both the arterial and venous lines (time A - time V) of the dialyzer. In 7 of 22 patients intracellular PTX3 levels in neutrophils were measured at the end of session. RESULTS: PTX3 venous levels were significantly increased at the end of the index session compared with baseline and in blood samples drawn from the venous line compared with the arterial line of the dialyzer. At time 1, a reduction of intracellular PTX3 in neutrophils was noticed. In contrast, CRP plasma levels were stable during the HD session. CONCLUSIONS: Our findings suggest that PTX3, which is rapidly produced by several cell types and released by neutrophils upon stimulation, could be a biomarker of HD-induced inflammation and of blood-membrane bioincompatibility.

A mouse model for spatial and temporal expression of HGF in the heart.

In order to study the effects of Hepatocyte Growth Factor (HGF) in the heart, two transgenic mice were developed, one carrying a bidirectional HGF-TetO-GFP responder construct and the other carrying a α-MHC-tTA transactivator construct. Crosses were carried out between heterozygotes, so that litters contained bitransgenic α-MHC-tTA/HGF-TetO-GFP+, thus expressing HGF and GFP exclusively in the heart and only in the absence of Doxycycline. Our data show that the expression of HGF was indeed restricted to the heart and that the expression was limited to the timeframe of the absence of Doxycycline. Surprisingly the expression was variable even between bitransgenic littermates. In the setting of a model of ischemia-reperfusion, the expression of HGF ameliorates cardiac functionality, enhances proliferation and diminishes the scarred area, proving that this is a good model to study the beneficial influences and functional roles of HGF in the heart.

Plasma levels of pentraxin-3, an acute phase protein, are increased during sickle cell painful crisis.

The painful crisis accounts for the majority of sickle cell disease (SCD) related hospital admissions. The prototypic long pentraxin 3 (PTX3), an acute phase protein, is elevated in patients with inflammatory and ischemic states. As the sickle cell painful crisis is associated with both inflammation and tissue ischemia, we questioned whether plasma PTX3 levels are increased during and associated with painful crisis severity. Furthermore, since PTX3 up-regulates endothelial expression of tissue factor we studied PTX levels in relation to markers of endothelial and coagulation activation. Plasma levels of PTX3, ultra-sensitive C-reactive protein (US-CRP), prothrombin fragment 1+2, thrombin-antithrombin (TAT) complexes, von Willebrand Factor antigen and soluble vascular adhesion molecule-1 were determined in 105 asymptomatic sickle cell patients, 33 patients during painful crisis and 30 race matched healthy controls. Plasma PTX3 levels were comparable between patients in asymptomatic state and healthy controls, but significantly higher during painful crisis (P<0.01). US-CRP levels were higher in asymptomatic patients compared to controls (P<0.0001) and increased further during painful crisis (P<0.0001). PTX3 levels at presentation with painful crisis correlated significantly with the duration of subsequent hospital admission (r(s) = 0.43; P = 0.013), whereas US-CRP levels did not. PTX3 levels did not correlate with markers of hypercoagulability. The increase of PTX3 levels during painful crisis and their relation to the duration of subsequent hospital stay suggest that PTX3 might serve both as a diagnostic and severity marker of the painful sickle cell crisis.

Inflammation and thrombosis in essential thrombocythemia and polycythemia vera: different role of C-reactive protein and pentraxin 3.

We tested the hypothesis that levels of pentraxin high sensitivity C-reactive protein and pentraxin 3 might be correlated with cardiovascular complications in patients with essential thrombocythemia and polycythemia vera. High sensitivity C-reactive protein and pentraxin 3 were measured in 244 consecutive essential thrombocythemia and polycythemia vera patients in whom, after a median follow up of 5.3 years (range 0-24), 68 cardiovascular events were diagnosed. The highest C-reactive protein tertile was compared with the lowest (>3 vs. <1 mg/L) and correlated with age (P=0.001), phenotype (polycythemia vera vs. essential thrombocythemia, P=0.006), cardiovascular risk factors (P=0.012) and JAK2V617F allele burden greater than 50% (P=0.003). Major thrombosis rate was higher in the highest C-reactive protein tertile (P=0.01) and lower at the highest pentraxin 3 levels (P=0.045). These associations remained significant in multivariate analyses and indicate that blood levels of high sensitivity C-reactive protein and petraxin 3 independently and in opposite ways modulate the intrinsic risk of cardiovascular events in patients with myeloproliferative disorders.

Predicting atrial fibrillation recurrence with circulating inflammatory markers in patients in sinus rhythm at high risk for atrial fibrillation: data from the GISSI atrial fibrillation trial.

BACKGROUND: Inflammation may play a significant role in the pathogenesis of atrial fibrillation (AF). OBJECTIVES: To examine the roles of three systemic inflammatory markers in predicting recurrent AF. METHODS: The association between the plasma concentrations of high-sensitivity C reactive protein (hsCRP), interleukin-6 (IL-6) and pentraxin-3 (PTX3) with echocardiographic parameters and with the time to first recurrence of AF was tested in 382 patients with a history of AF but in sinus rhythm at randomisation, enrolled in the GISSI-AF biohumoral study. RESULTS: Baseline PTX3 was related to left atrial, but not to left ventricular chamber volume. During one year of follow-up, 204 patients (53.1%) had a recurrent AF. There were no significant differences in baseline median [Q1-Q3] plasma concentrations of IL-6, hsCRP and PTX3 among patients with (2.11 [1.47-3.74] pg/ml, 3.30 [1.40-6.80] mg/l and 4.66 [3.27-6.97] ng/ml, respectively) or without recurrent AF (2.09 [1.37-2.90] pg/ml, p=0.182; 3.00 [1.10-6.20] mg/l, p=0.333; 5.09 [3.22-7.98] ng/ml, p=0.637). At 6 and 12 months follow-up, AF patients had significantly higher concentrations of IL-6 and PTX3 than those in sinus rhythm, and those with most recent episodes of AF had higher hsCRP. Baseline levels of IL-6, hsCRP or PTX3 were not significantly associated with a higher risk of recurrence of AF. CONCLUSION: In patients with a history of AF, but without significant left ventricular dysfunction or heart failure, inflammatory biomarkers may be raised but are, at best, weak predictors of the risk for first recurrence of AF.

Increased levels of serum pentraxin 3, a novel cardiovascular biomarker, in patients with inflammatory rheumatic disease.

OBJECTIVE: Pentraxin 3 (PTX3), a key component of innate immunity, is a strong marker of disease severity in coronary artery disease (CAD). The aim of this study was to compare levels of serum PTX3 in CAD patients with and without inflammatory rheumatic disease (IRD) and in healthy controls. METHODS: We examined 69 patients with IRD (CAD/IRD group) and 53 patients without IRD (CAD/non-IRD) referred to coronary artery bypass grafting, and 30 healthy controls. RESULTS: The mean +/- SD serum PTX3 level in the CAD/IRD group was 1.96 +/- 0.98 ng/ml; this was statistically significantly higher than that of the CAD/non-IRD (1.41 +/- 0.74 ng/ml) and healthy control (1.21 +/- 0.59 ng/ml) groups. In contrast to most other IRDs, serum PTX3 levels were relatively low in patients with systemic lupus erythematosus (SLE) and other systemic connective tissue diseases. In sex- and age-adjusted analysis, IRD, acute coronary syndromes, and low alcohol intake were associated with higher serum PTX3 levels. CONCLUSION: CAD patients with IRD had higher mean serum PTX3 levels than patients without IRD and healthy controls. In addition, acute coronary syndromes and low alcohol intake independently predicted higher serum PTX3 levels. Higher serum PTX3 levels in IRD may be related to the higher cardiovascular risk of IRD patients. Circulating PTX3 could likely be used as a biomarker for severity of cardiovascular disease in IRDs; its importance, however, might be limited in SLE and related disorders.

Regulation of leukocyte recruitment by the long pentraxin PTX3.

Pentraxins are a superfamily of conserved proteins involved in the acute-phase response and innate immunity. Pentraxin 3 (PTX3), a prototypical member of the long pentraxin subfamily, is a key component of the humoral arm of innate immunity that is essential for resistance to certain pathogens. A regulatory role for pentraxins in inflammation has long been recognized, but the underlying mechanisms remain unclear. Here we report that PTX3 bound P-selectin and attenuated neutrophil recruitment at sites of inflammation. PTX3 released from activated leukocytes functioned locally to dampen neutrophil recruitment and regulate inflammation. Antibodies have glycosylation-dependent regulatory effect on inflammation. Therefore, PTX3, which is an essential component of humoral innate immunity, and immunoglobulins share functional outputs, including complement activation, opsonization and, as shown here, glycosylation-dependent regulation of inflammation.

Persisting high levels of plasma pentraxin 3 over the first days after severe sepsis and septic shock onset are associated with mortality.

PURPOSE: Pentraxin 3 (PTX3) is an inflammatory mediator produced by neutrophils, macrophages, myeloid dendritic and endothelial cells. During sepsis a massive inflammatory activation and coagulation/fibrinolysis dysfunction occur. PTX3, as a mediator of inflammation, may represent an early marker of severity and outcome in sepsis. METHODS: This study is based on a prospective trial regarding the impact of glycemic control on coagulation in sepsis. Ninety patients admitted to three general intensive care units were enrolled when severe sepsis or septic shock was diagnosed. At enrollment, we recorded sepsis signs, disease severity, coagulation activation [prothrombin fragments 1 + 2 (F(1+2))] and fibrinolysis inhibition [plasminogen activator inhibitor-1 (PAI-1)]. We measured plasma PTX3 levels at enrollment, everyday until day 7, then at days 9, 11, 13, 18, 23 and 28. Mortality was recorded at day 90. RESULTS: Although not different on day 1, PTX3 remained significantly higher in non-survivors than in survivors over the first 5 days (p = 0.002 by general linear model). On day 1, PTX3 levels were higher in septic shock than in severely septic patients (p = 0.029). Day 1 PTX3 was significantly correlated with platelet count (p < 0.001), SAPS II score (p = 0.006) and SOFA score (p < 0.001). Day 1 PTX3 was correlated with F(1+2) concentration and with PAI-1 activity and concentration (p < 0.05 for all). CONCLUSIONS: Persisting high levels of circulating PTX3 over the first days from sepsis onset may be associated with mortality. PTX3 correlates with severity of sepsis and with sepsis-associated coagulation/fibrinolysis dysfunction.