Abundance of the long pentraxin PTX3 at sites of leukocytoclastic lesions in patients with small-vessel vasculitis

The pentraxin family in autoimmune disease

The pentraxins represent a family of multifunctional proteins composed of long and short pentamers. The latter includes serum amyloid P component (SAP) and C-reactive protein (CRP) whereas the former includes neuronal PTX1 and PTX2 (NPTX1 and NPTX2, respectively), PTX3 and PTX4. These serve as a bridge between adaptive immunity and innate immunity and a link between inflammation and immunity. Similarities and differences between long and short pentamers are examined and their roles in autoimmune disease are discussed. Increased CRP and PTX3 could indicate the activity of rheumatoid arthritis, systemic lupus erythematosus or other autoimmune diseases. Mechanistically, CRP and PTX3 may predict target organ injury, regulate bone metabolic immunity and maintain homeostasis as well as participate in vascular endothelial remodeling. Interestingly, PTX3 is pleiotropic, being involved in inflammation and tissue repair. Given the therapeutic potential of PTX3 and CRP, targeting these factors to exert a beneficial effect is the focus of research efforts. Unfortunately, studies on NPTX1, NPTX2, PTX4 and SAP are scarce and more research is clearly needed to elaborate their potential roles in autoimmune disease.

Serum pentraxin 3 in systemic lupus erythematosus: A potential indicator of cutaneous disease activity

BACKGROUND

Although skin manifestations are common in systemic lupus erythematosus (SLE), there is still a lack of a diagnostic marker for cutaneous involvement. Pentraxin3 (PTX3) has been studied in SLE patients; however, it has not been investigated in relation to cutaneous manifestations.

OBJECTIVE

To assess the serum PTX3 level in SLE patients, and to investigate its relationship with disease activity as well as with variable skin manifestations.

PATIENTS AND METHODS

Thirty-four patients with SLE (17 patients with skin manifestations and 17 without) and 30 healthy subjects were included in the study. Patients were evaluated clinically for systemic and skin manifestations of SLE. Systemic Lupus Erythematosus Disease Activity Index (SLEDAI-2k) and Cutaneous Lupus Erythematosus Activity and Severity Index (CLASI) scores were calculated. Serum level of PTX3 was measured in patients and controls using ELISA.

RESULTS

Higher serum PTX3 level was found in SLE patients compared to controls (p < 0.001). Patients with skin manifestations showed higher SLEDAI-2k scores and had higher PTX3 level compared to those without skin manifestations (p = 0.015 and p < 0.001, respectively). PTX3 showed higher levels in association with malar rash (p < 0.001), mucosal ulcers (p < 0.001), alopecia (p < 0.001), and purpuric eruption (p = 0.002). Moreover, PTX3 level positively correlated with CLASI scores (p < 0.001).

CONCLUSION

Our results reinforce the important role of Pentraxin3 in SLE patients with skin manifestations, and it may be considered an interesting biomarker for the pattern and extent of cutaneous involvement in SLE.

The crossroad between autoimmune disorder, tissue remodeling and cancer of the thyroid: The long pentraxin 3 (PTX3)

Thyroid is at the crossroads of immune dysregulation, tissue remodeling and oncogenesis. Autoimmune disorders, nodular disease and cancer of the thyroid affect a large amount of general population, mainly women. We wondered if there could be a common factor behind three processes (immune dysregulation, tissue remodeling and oncogenesis) that frequently affect, sometimes coexisting, the thyroid gland. The long pentraxin 3 (PTX3) is an essential component of the humoral arm of the innate immune system acting as soluble pattern recognition molecule. The protein is found expressed in a variety of cell types during tissue injury and stress. In addition, PTX3 is produced by neutrophils during maturation in the bone-marrow and is stored in lactoferrin-granules. PTX3 is a regulator of the complement cascade and orchestrates tissue remodeling and repair. Preclinical data and studies in human tumors indicate that PTX3 can act both as an extrinsic oncosuppressor by modulating complement-dependent tumor-promoting inflammation, or as a tumor-promoter molecule, regulating cell invasion and proliferation and epithelial to mesenchymal transition, thus suggesting that this molecule may have different functions on carcinogenesis. The involvement of PTX3 in the regulation of immune responses, tissue remodeling and oncosuppressive processes led us to explore its potential role in the development of thyroid disorders. In this review, we aimed to highlight what is known, at the state of the art, regarding the connection between the long pentraxin 3 and the main thyroid diseases i.e., nodular thyroid disease, thyroid cancer and autoimmune thyroid disorders.

IgG anti-Pentraxin 3 antibodies are a novel biomarker of ANCA-associated vasculitis and better identify patients with eosinophilic granulomatosis with polyangiitis

OBJECTIVE

To investigate prevalence of anti-Pentraxin 3 (PTX3) antibodies in sera of anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients.

METHODS

Anti-PTX3 and PTX3 levels were analysed by enzyme-linked immunosorbent assays in sera from unselected patients with AAV and compared with patients with systemic lupus erythematosus (SLE, n = 130), other connective tissue diseases (CTDs, n = 97) and matched healthy controls (n = 97). Optical density (OD) cut-off for positive anti-PTX3 antibodies was determined by ROC curve analysis and set as 0.234. Indirect immunofluorescence (IIF) on fixed human granulocytes was used to analyze the fluorescence pattern of anti-PTX3 antibodies. Liquid-phase inhibition tests were conducted to assess potential interferences.

RESULTS

We included 101 AAV patients (females 58%, median age 60[51-69] years) affected either with granulomatosis with polyangiitis (GPA, n = 51), microscopic polyangiitis (MPA, n = 12) or eosinophilic granulomatosis with polyangiitis (EGPA, n = 38). Anti-PTX3 antibodies were detected in 29.7% AAV patients, being significantly higher than in healthy controls (p < 0.001) and CTDs (p = 0.030) but lower than in SLE (p = 0.004). Anti-PTX3 antibody prevalence was 44.7% in EGPA, 25% in MPA and 19% in GPA (p = 0.034). Among ANCA negative patients, 35.7% displayed positive anti-PTX3 antibodies. Anti-PTX3 were associated with a lower prevalence of systemic (p = 0.002), ear-nose-throat (p = 0.006) and renal manifestations (p = 0.016). Anti-PTX3 antibodies were characterized by a specific IIF pattern on fixed granulocytes. PTX3 serum levels resulted lower in AAV than healthy controls (p < 0.001). PTX3 inhibited anti-PTX3 binding in a dose-dependent manner.

CONCLUSIONS

Anti-PTX3 autoantibodies appear a promising novel biomarker of AAV, especially EGPA.

Pentraxin 3 levels and correlation with disease severity in patients with acute rheumatic fever

Objectives

This study aims to investigate serum pentraxin 3 (PTX3) levels during acute episode of acute rheumatic fever (ARF) and their relationship with disease severity.

Patients and methods

The prospective study was conducted between January 2015 and December 2018 and included 52 ARF patients (22 girls, 30 boys, mean age 10.7±2.1 years; range, 5 to 16 years) experiencing an acute episode and 22 healthy children (13 girls, 9 boys, mean age 10.3±3.8 years; range, 5 to 16 years). ARF patients were classified into three groups based on the clinical course: isolated arthritis (n=17), mild carditis (n=19), and moderate/severe carditis (n=16). Blood samples were collected from all patients before treatment and from the healthy children in the control group to measure PTX3 levels. PTX3 was measured using sandwich enzyme-linked immunosorbent assay method.

Results

Plasma PTX3 levels were significantly higher in ARF group compared to the control group (4.7±5.2 and 1.2±1.7 ng/mL, p<0.001). Subgroup analysis of serum PTX3 levels in ARF patients with isolated arthritis, mild carditis, and moderate/severe carditis (3.2±3.1 ng/mL, 4.3±5 ng/mL, and 6.7±6.6 ng/mL, respectively) showed that serum PTX3 was significantly higher in the moderate/severe carditis group compared to the other groups (p<0.05). Analysis of echocardiographic data showed that serum PTX3 was positively correlated with left ventricular end-diastolic diameter, left atrial diameters, and mitral A velocity and negatively correlated with E/A ratio (p<0.05; r=0.231, 0.402, 0.562, -0.586, respectively).

Conclusion

High PTX3 level during an acute episode of ARF may help predict the clinical course and the severity of accompanying carditis. However, prospective studies with larger sample sizes are needed.

Empagliflozin Inhibits IL-1β-Mediated Inflammatory Response in Human Proximal Tubular Cells

SGLT2 inhibitor-related nephroprotection is—at least partially—mediated by anti-inflammatory drug effects, as previously demonstrated in diabetic animal and human studies, as well as hyperglycemic cell culture models. We recently presented first evidence for anti-inflammatory potential of empagliflozin (Empa) under normoglycemic conditions in human proximal tubular cells (HPTC) by demonstrating Empa-mediated inhibition of IL-1β-induced MCP-1/CCL2 and ET-1 expression on the mRNA and protein level. We now add corroborating evidence on a genome-wide level by demonstrating that Empa attenuates the expression of several inflammatory response genes in IL-1β-induced (10 ng/mL) normoglycemic HPTCs. Using microarray-hybridization analysis, 19 inflammatory response genes out of >30.000 human genes presented a consistent expression pattern, that is, inhibition of IL-1β (10 ng/mL)-stimulated gene expression by Empa (500 nM), in both HK-2 and RPTEC/TERT1 cells. Pathway enrichment analysis demonstrated statistically significant clustering of annotated pathways (enrichment score 3.64). Our transcriptomic approach reveals novel genes such as CXCL8/IL8, LOX, NOV, PTX3, and SGK1 that might be causally involved in glycemia-independent nephroprotection by SGLT2i.

Macrophage expression and prognostic significance of the long pentraxin PTX3 in COVID-19

Long pentraxin 3 (PTX3) is an essential component of humoral innate immunity, involved in resistance to selected pathogens and in the regulation of inflammation^1-3. The present study was designed to assess the presence and significance of PTX3 in Coronavirus Disease 2019 (COVID-19)^4-7. RNA-sequencing analysis of peripheral blood mononuclear cells, single-cell bioinformatics analysis and immunohistochemistry of lung autopsy samples revealed that myelomonocytic cells and endothelial cells express high levels of PTX3 in patients with COVID-19. Increased plasma concentrations of PTX3 were detected in 96 patients with COVID-19. PTX3 emerged as a strong independent predictor of 28-d mortality in multivariable analysis, better than conventional markers of inflammation, in hospitalized patients with COVID-19. The prognostic significance of PTX3 abundance for mortality was confirmed in a second independent cohort (54 patients). Thus, circulating and lung myelomonocytic cells and endothelial cells are a major source of PTX3, and PTX3 plasma concentration can serve as an independent strong prognostic indicator of short-term mortality in COVID-19.

Pentraxin 3 in Cardiovascular Disease

The long pentraxin PTX3 is a member of the pentraxin family produced locally by stromal and myeloid cells in response to proinflammatory signals and microbial moieties. The prototype of the pentraxin family is C reactive protein (CRP), a widely-used biomarker in human pathologies with an inflammatory or infectious origin. Data so far describe PTX3 as a multifunctional protein acting as a functional ancestor of antibodies and playing a regulatory role in inflammation. Cardiovascular disease (CVD) is a leading cause of mortality worldwide, and inflammation is crucial in promoting it. Data from animal models indicate that PTX3 can have cardioprotective and atheroprotective roles regulating inflammation. PTX3 has been investigated in several clinical settings as possible biomarker of CVD. Data collected so far indicate that PTX3 plasma levels rise rapidly in acute myocardial infarction, heart failure and cardiac arrest, reflecting the extent of tissue damage and predicting the risk of mortality.

The long pentraxin PTX3: A prototypical sensor of tissue injury and a regulator of homeostasis

Tissue damage frequently occurs. The immune system senses it and enforces homeostatic responses that lead to regeneration and repair. The synthesis of acute phase molecules is emerging as a crucial event in this program. The prototypic long pentraxin PTX3 orchestrates the recruitment of leukocytes, stabilizes the provisional matrix in order to facilitate leukocyte and stem progenitor cells trafficking, promotes swift and safe clearance of dying cells and of autoantigens, limiting autoimmunity and protecting the vasculature. These non-redundant actions of PTX3 are necessary for the resolution of inflammation. Recent studies have highlighted the mechanisms by which PTX3 adapts the functions of innate immune cells, orchestrates tissue repair and contributes to select the appropriate acquired immune response in various tissues. Conversely, PTX3 continues to be produced in diseases where the inflammatory response does not resolve. It is therefore a valuable biomarker for more precise and personalized stratification of patients, often independently predicting clinical evolution and outcome. There is strong promise for novel therapies based on understanding the mechanisms with which PTX3 plays its homeostatic role, especially in regulating leukocyte migration and the resolution of inflammatory processes.

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.

Update on the role of Pentraxin 3 in atherosclerosis and cardiovascular diseases

Pentraxin 3 (PTX3) is an acute-phase protein that was recently demonstrated to play pleiotropic activities in cardiovascular (CV) diseases. Tumor necrosis factor and interleukins up-regulates PTX3 transcription in different cell types (i.e. endothelial cells, phagocytes, smooth muscle cells, fibroblasts and glial cells) involved in atherogenesis. By interacting with numerous ligands, PTX3 acts as a modulatory molecule of complement system, inflammatory response, angiogenesis, and vascular/tissue remodeling. Experimental data point to a beneficial role of PTX3 in atherosclerotic plaque development and vulnerability. Animal studies indicated a protective role of PTX3 signaling in ischemic/reperfusion injury and failing heart. Clinical studies have so far provided contrasting results, highlighting a debated role of PTX3 as an active mediator of endothelial dysfunction, atherosclerotic plaque vulnerability and worse outcome after ischemic events. Therefore, substantial evidence suggests a dual role of PTX3 as modulator or amplifiers of the innate immune response. The final result of PTX3 activation might be determined by a fine tuning of time, space and environmental signals. The aim of this review is to provide an overview of biological properties of PTX3 in CV diseases and to discuss the ability of PTX3 to act as a crossroad between pro- and anti-inflammatory pathways.

Is vascular endothelial growth factor a useful biomarker in giant cell arteritis?

Objectives

To assess the performance of circulating vascular endothelial growth factor (VEGF) levels as a tool for diagnosing giant cell arteritis (GCA) in a cohort of patients referred for assessment of suspected GCA.

Methods

We selected 298 patients recruited to the multicentre study Temporal Artery Biopsy versus Ultrasound in diagnosis of suspected GCA (TABUL). In a random subset of 26 biopsy-proven GCA cases and 26 controls, serum from weeks 0, 2 and 26 was analysed for VEGF concentration using ELISA. VEGF concentration at week 0 was used to generate a receiver-operating characteristic curve and thereby identify a cut-off for an abnormal result which was used to analyse the full patient cohort. Sections of paraffin-embedded temporal artery were stained by immunohistochemistry for VEGF.

Results

The mean (95% CI) VEGF concentration at week 0 was 873 pg/mL (631 to 1110) in 26 patients versus 476 pg/mL (328 to 625) in 26 controls (p=0.017). This difference was not observed at any other time point. The optimal cut-off of 713 pg/mL was applied to the whole patient cohort (n=298), yielding sensitivity of 32% and specificity of 85%. This was not improved by combination with any clinical parameters. When patients with biopsy-proven GCA were compared with controls, sensitivity was 58% and specificity remained 85%. Sections of biopsy from biopsy-positive GCA showed intense staining in the adventitia which was not seen in controls.

Conclusions

Serum VEGF concentration predicts biopsy positivity but is not useful for differentiating clinical cases of GCA from controls. Further studies into VEGF as a prognostic marker and therapeutic target are warranted.

Trial registration number

NCT00974883; Post-results.

Pentraxin-3 levels are associated with vasculitis and disease activity in childhood-onset systemic lupus erythematosus

Objectives Childhood-onset systemic lupus erythematosus (cSLE) is a multisystemic autoimmune disease characterized by inflammatory organ damage by means of vasculitis. Pentraxin-3 (PTX3) is expressed locally at the sites of inflammatory processes, predominantly from endothelial cells. In adult studies, PTX3 has shown to be an indicator of active vasculitis both in large-vessel and small-vessel vasculitides, as well as in SLE. Moreover, in SLE it has found to be correlated with disease activity, and with some of the clinical manifestations and laboratory parameters. We aimed to ascertain if PTX3 might be a significant mediator in cSLE and if it might indicate active vasculitis during the course of the disease. Methods Serum PTX3 levels were measured in 76 patients with cSLE and 41 healthy subjects. We have investigated its relation with disease activity, damage, clinical features, laboratory parameters and medications. Results Serum levels of PTX3 were found to be increased in cSLE compared to healthy controls (mean ± SD; 10.6 ± 8.2 ng/mL vs 2.7 ± 1.3 ng/mL, p < 0.001). PTX3 concentrations were also in correlation with SLEDAI-2K ( r = 0.57, p < 0.001). When viewed from the clinical perspective, serum PTX3 levels were significantly higher only in patients with active vasculitis ( p < 0.001), Raynaud phenomenon ( p = 0.006) and mucocutaneous manifestations ( p < 0.001). However, an association between PTX3 and age, age at disease onset, disease duration, complement levels, PedSDI score (pediatric version of the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index), ESR, CRP, procalcitonin levels, anti-ds DNA antibody, anticardiolipin antibodies was not detected. Conclusions Patients with cSLE have increased levels of serum PTX3 compared to healthy controls. Thus, serum PTX-3 level might be a significant mediator in cSLE. Apart from these, the results support that PTX3 reflects active cutaneous vasculitis in cSLE and correlates with disease activity.

Leukocytoclastic Vasculitis with Systemic Involvement Associated with Ciprofloxacin Therapy: Case Report and Review of the Literature

A 71-year-old woman presented with constitutional signs and lower extremity palpable purpura after being prescribed a four-day course of 500 mg of ciprofloxacin two times daily for a gastrointestinal infection. She was admitted for inpatient treatment. During the third hospital day, she presented with an episode of abundant hematemesis while her skin lesions remained unchanged. Upper endoscopy revealed multiple lesions consistent with vasculitis and histological examination of the skin biopsy disclosed a leukocytoclastic vasculitis. The patient was successfully treated with prednisone following ciprofloxacin discontinuation. Complete resolution of the lesions on drug withdrawal strongly suggested drug toxicity, which was further supported by a score of 8 in the Naranjo Adverse Drug Reaction Probability Scale. Awareness that the development of skin and gastrointestinal lesions following administration of ciprofloxacin may be a manifestation of ciprofloxacin-induced vasculitis can help early detection, treatment, and lead to an overall good prognosis.

Role of PTX3 in corneal epithelial innate immunity against Aspergillus fumigatus infection

Pentraxin3 (PTX3), a member of long pentraxin family, plays a non-redundant role in human humoral innate immunity. However, whether PTX3 is expressed by corneal epithelial cells and its role during corneal fungi infection has not yet been investigated. To identify the presence of PTX3 in cornea, the possible mechanisms involved in its expression, and also the effects on corneal anti-fungi innate immune response, clinic human corneal tissues and cultured human corneal epithelial cells (HCECs) were resorted. PTX3 mRNA and protein were detected in corneal samples and cultured HCECs, which was significantly up-regulated after exposing to Aspergillus fumigatus (A. fumigatus). Pretreated with specific inhibitors, only Syk contributed to the regulation of PTX3 expression in Dectin-1/Syk signal axis. Furthermore, among the MAPK members (p38 MAPK, ERK1/2 and JNK), only ERK1/2 and JNK were responsible for A. fumigatus induced PTX3 production. Blocking of endogenous PTX3 by siRNA down-regulated the production of IL-1β at both mRNA and protein levels. Meanwhile, blocking of PTX3 also inhibited the phosphorylation of ERK1/2 and JNK, but not p38 MAPK. These findings demonstrate that PTX3 is expressed in human corneal epithelial cells and Syk, ERK1/2, JNK signaling pathways play an important role in the regulation of PTX3 induction. PTX3 plays a proinflammatory role in corneal epithelial anti-fungi immune response by affecting the production of IL-1β and activation of some proinflammatory signaling pathways (ERK1/2 and JNK).

Low serum fibroblast growth factor 2 levels not accompanied by increased serum pentraxin 3 levels in patients with systemic sclerosis

There are scarce clinical data regarding serum pentraxin 3 (PTX3) and fibroblast growth factor 2 (FGF2) in patients with systemic sclerosis (SSc). Study was conducted to evaluate serum levels in our SSc cohort. Serum PTX3 and FGF2 concentrations were compared among SSc, disease control (systemic lupus erythematosus (SLE)), and healthy control groups. We also examined the association of serum levels of PTX3 and FGF2 with disease manifestations. Serum PTX3 levels were similarly distributed among SSc (n = 93) and healthy groups (n = 66) (p = 1.00) while PTX3 levels were higher in SLE controls (n = 86) compared to both SSc and healthy groups. PTX3 levels were higher in limited SSc cases compared to diffuse cases (p = 0.016). Median PTX3 levels in SSc cases with lung involvement were lower compared to cases with no lung involvement (p = 0.006). Patients with SSc had significantly lower serum levels of FGF2 compared to SLE and healthy groups. Serum FGF2 concentration was undetectable in 61.3% of cases with SSc while 30.2% of SLE and only 4.5% of healthy cases had undetectable FGF2 levels (p < 0.01). Diffuse and limited SSc cases, as well as cases with and without lung involvement, had similar rates of undetectable serum FGF2 levels (p = 0.15 and p = 0.59, respectively). FGF2 levels were mostly undetectably low in patients with SSc, and serum PTX3 was lower in diffuse SSc and in cases with lung involvement compared to limited SSc and cases with no lung involvement, respectively, in our cohort.

Serum pentraxin 3 levels are negatively associated with carotid intima media thickness in non-obese rheumatoid arthritis patients

BACKGROUND

Pentraxin-3 (PTX3) is a long pentraxin that is supposed to participate in the inflammatory process and in atherosclerosis.

AIM

To study PTX3 serum levels in rheumatoid arthritis (RA) patients to know if its serum levels may reflect disease activity and/or subclinical atherosclerosis.

METHODS

PTX3 and carotid intima media thickness (IMT) were studied in 85 RA patients (83.5% females, median age of 59years old, median disease duration of 13years) along with its demographic, clinical, serological and lipid profile. For comparison PTX3 was measured in 85 healthy volunteers.

RESULTS

PTX3 levels in RA patients were similar to controls (p=0.21) and did not correlate with inflammatory activity measured by ESR (p=0.39) CRP (p=0.18) and DAS28 (p=0.67). Serum PTX3 levels were higher in nonobese RA patients than in obese (BMI vs PTX3 with rho=-0.27; 95%IC=-0.46 to -0.06; p=0.009). In non-obese patients, PTX3 correlated negatively with carotid IMT (rho=-0.40; 95%IC=-0.66 to -0.06; p=0.01) but not in the obese ones (p=0.26). In the obese RA patients there was a negative correlation between PTX3 levels and LDL/HDL ratio (Rho=-0.29; 95%IC=-0.53-0.01; p=0.03).

CONCLUSIONS

PTX3 levels do not reflect inflammatory process in RA. However, it exerts a protective role in the process of atherogenesis in non-obese RA patients.

Detection of Anti-Pentraxin-3 Autoantibodies in ANCA-Associated Vasculitis

OBJECTIVES

Pentraxin 3 (PTX3), in common with myeloperoxidase and proteinase 3, is stored in human neutrophil granules and is expressed on apoptotic neutrophil surface. We therefore investigated the presence of anti-PTX3 autoantibodies (aAbs) in the sera of antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients.

METHODS

Presence of anti-PTX3 autoantibodies was analysed by a specific enzyme-linked immunosorbent assay in sera from 150 patients with microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA), and in sera of 227 healthy subjects (HS), 40 systemic sclerosis (SSc) patients, and 25 giant cell arteritis patients (GCA). Using indirect immunofluorescence on fixed human neutrophils, we also analyzed the staining pattern associated with the presence of anti-PTX3 aAbs.

RESULTS

Anti-PTX3 aAbs were detected in 56 of 150 (37.3%) of the AAV patients (versus 12 of 227 (5.3%) of HS, p<0.001) and, interestingly, in 7 of 14 MPO and PR3 ANCA negative AAV patients. Moreover, by indirect immunofluorescence on fixed neutrophils, anti-PTX3 aAbs gave rise to a specific cytoplasmic fluorescence pattern distinct from the classical cytoplasmic (c-ANCA), perinuclear (p-ANCA), and atypical (a-ANCA) pattern. Anti-PTX3 aAbs levels were higher in patients with active AAV as compared to patients with inactive disease.

CONCLUSION

Our work suggests that PTX3 is as a novel ANCA antigen. Anti-PTX3 aAbs appear thus as a promising novel biomarker in the diagnosis of AAV, including in patients without detectable MPO and PR3 ANCA.

Pentraxin 3 Is Closely Associated With Tubulointerstitial Injury in Lupus Nephritis: A Large Multicenter Cross-Sectional Study

Lupus nephritis always elicits immune inflammatory tissue damages in kidney. Pentraxin 3 (PTX3), mainly produced at inflammatory sites, is known to be involved in the regulation of the innate immunity system. The aim of this study was to investigate the serum and urine levels of PTX3, and the expression of PTX3 in renal tissues in lupus nephritis patients from a large Chinese cohort.The study used cross-sectional survey and 288 active lupus nephritis patients, including discovery cohort and validation cohort, 115 systemic lupus erythematosus (SLE) patients without clinical renal involvement and 46 healthy controls were enrolled. Serum and urine PTX3 were screened by enzyme-linked immunosorbent assay (ELISA). The renal deposition of PTX3 was detected by immunohistochemistry and immunofluorescence.The average level of serum PTX3 in the discovery cohort of lupus nephritis was significantly higher than that in nonrenal involvement SLE group and normal controls (P < 0.001, P < 0.001, respectively), which was confirmed by the validation cohort. Serum PTX3 levels of 15 lupus nephritis patients in remission decreased significantly compared with that in active phase. Serum PTX3 levels were significantly higher in patients with hematuria (P = 0.014), leucocyturia (P = 0.002), acute renal failure (P = 0.001), and nephrotic syndrome (P = 0.036). There were significant correlations between serum PTX3 levels and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, serum creatinine value, renal pathological activity indices, and serum complement 3 (C3) in active lupus nephritis patients. The urinary PTX3 levels were significantly higher in active lupus nephritis patients compared with patients in remission and normal controls (P = 0.011, P = 0.008, respectively). There were significant associations between urinary PTX3 levels and multiple indices of tubulointerstitial lesions, including urinary KIM-1 (r = 0.368, P = 0.016), neutrophil gelatinase-associated lipocalin (NGAL) (r = 0.320, P = 0.039), microalbumin (r = 0.621, P = 0.003), transferring (r = 0.451, P = 0.040) levels and renal pathological indices scores, especially interstitial inflammation (r = 0.349, P = 0.025) in active lupus nephritis patients. A significant correlation was found between serum and urine PTX3 levels (r = 0.431, P = 0.006). PTX3 staining was mainly observed in tubulointerstitial areas of patients with lupus nephritis, and immunofluorescence study showed that PTX3 could colocalize with fibroblast in interstitium.Circulating and local PTX3 levels were significantly increased in patients with active lupus nephritis and might be a biomarker for the disease progression, especially of tubulointerstitial injury.

Serum levels of alpha-1 acid glycoprotein and pentraxin 3 in patients with Behçet's disease and relationship with disease activity

BACKGROUND

To evaluate the relationship between disease activity and levels of alpha 1-acid glycoprotein and pentraxin 3 in patients with Behçet's disease (BD).

METHODS

Forty-eight patients with BD and 29 age- and gender-matched healthy control subjects were included in the study. Serum pentraxin 3 levels were measured using enzyme-linked immunosorbent assay (ng/ml), and alpha 1-acid glycoprotein levels were measured using nephelometry (mg/dl). Disease activity was assessed using the BD Current Activity Form (BDCAF).

RESULTS

Serum alpha-1 acid glycoprotein levels were significantly higher in patients with BD compared to the control group (P = 0.048). There were no significant differences between two groups in terms of levels of pentraxin 3 (P = 0.697). According to Pearson's analysis, alpha 1-acid levels are significantly positively correlated with erythrocyte sedimentation rate, C-reactive protein, and skin lesions and arthritis of BDCAF scores. Pentraxin 3 levels did not correlate with erythrocyte sedimentation rate, C-reactive protein, or any domains of BDCAF scores.

CONCLUSION

The results of the present study demonstrate that serum levels of alpha-1 acid glycoprotein were significantly higher in patients with BD relative to the control group. Alpha-1 acid glycoprotein is greatly associated with skin lesions and arthritis in patients with BD. We did not find high serum levels of PTX3 in patients with BD compared to healthy controls, and pentraxin 3 is not associated with disease activity in BD.

Could serum pentraxin 3 levels and IgM deposition in skin biopsies predict subsequent renal involvement in children with Henoch-Schönlein purpura?

BACKGROUND

The aim of this study was to evaluate the potential of serum pentraxin 3 (PTX3) values as an early predictor of subsequent renal involvement in patients with Henoch-Schönlein purpura (HSP) with no abnormalities on urinary examination and in renal function tests at disease onset.

METHODS

This was a prospective cohort study which included 60 pediatric patients with HSP (age range 3-15 years) who were diagnosed between February 2011 and October 2012 and 60 age- and sex-matched healthy controls. The patients were followed up for at least 18 months. Clinical findings were recorded for all patients at first examination, and blood samples for routine laboratory parameters and PTX3 value as well as skin biopsy specimens were obtained from each subject.

RESULTS

Of the 60 patients with HSP, 29 (48.3 %) developed subsequent renal involvement, of whom four underwent kidney biopsy. The mean serum PTX3 level of patients with subsequent renal involvement was significantly higher than those of patients without renal involvement and of the controls (2.20 ± 1.30 vs. 1.36 ± 0.85 and 1.03 ± 0.7 ng/ml, respectively; p = 0.004). Immunofluorescence evaluation of skin biopsy revealed that in addition to immunoglobulin A (IgA) deposition, the IgM deposition was significantly associated with subsequent renal involvement (p = 0.008).

CONCLUSIONS

A high PTX3 level and IgM staining in skin biopsies from HSP patients may be harbingers of subsequent renal involvement.

Elevated Expression of Pentraxin 3 in Anti-neutrophil Cytoplasmic Antibody-associated Glomerulonephritis with Normal Serum C-reactive Protein

A 20-year-old woman was admitted to our hospital with an elevated serum creatinine level of 1.61 mg/dL and a normal C-reactive protein level of less than 0.1 mg/dL. Her myeloperoxidase anti-neutrophil cytoplasmic antibody (ANCA) titer was slightly increased at 9.2 U/mL; a kidney biopsy revealed that 23 of 32 glomeruli had crescents. The expression of pentraxin 3 was detected in her kidney and her plasma pentraxin 3 level was elevated at 63.53 ng/mL. Plasma pentraxin 3 levels may be an activity marker for ANCA-associated glomerulonephritis, particularly when serum C-reactive protein levels are within the normal limits.

Systemic pentraxin-3 levels reflect vascular enhancement and progression in Takayasu arteritis

Introduction

Progression of arterial involvement is often observed in patients with Takayasu arteritis (TA) thought to be in remission. This reflects the failure of currently used biomarkers and activity criteria to detect smouldering inflammation occurring within arterial wall. Pentraxin-3 (PTX3) is a soluble pattern recognition receptor produced at sites of inflammation and could reveal systemic as well as localized inflammatory processes. We verified whether the blood concentrations of PTX3 and of C-reactive protein (CRP) in patients with Takayasu arteritis (TA) might reflect vascular wall involvement, as assessed by signal enhancement after contrast media administration, and the progression of arterial involvement.

Methods

A cross-sectional single-centre study was carried out on 42 patients with TA that comprised assessment of PTX3, of CRP and erythrocyte sedimentation velocity (ESR). In total, 20 healthy controls and 20 patients with Systemic Lupus Erythematous (SLE) served as controls. Vascular imaging was carried out by magnetic resonance angiography, doppler ultrasonography and computed tomography angiography.

Results

Patients with TA and SLE had higher plasmatic PTX3 and CRP concentrations than healthy controls (P = 0.009 and 0.017, respectively). PTX3 levels did not correlate with those of CRP. Patients with active systemic TA had significantly higher concentrations of CRP but similar levels of PTX3 than patients with quiescent disease. In contrast, patients with vascular inflammation detectable at imaging had higher PTX3 concentrations (P = 0.016) than those in which vessel inflammation was not evident, while CRP levels were similar. The concentration of PTX3 but not that of CRP was significantly higher in TA patients with worsening arterial lesions that were not receiving antagonists of tumor necrosis factor-α or interleukin-6.

Conclusions

Arterial inflammation and progression of vascular involvement influence plasma PTX3 levels in TA, while levels of CRP accurately reflect the burden of systemic inflammation. These results support the contention that PTX3 reflects different aspects of inflammation than CRP and might represent a biomarker of actual arteritis in TA.

Intravascular immunity as a key to systemic vasculitis: a work in progress, gaining momentum

Vascular inflammation contributes to the defence against invading microbes and to the repair of injured tissues. In most cases it resolves before becoming apparent. Vasculitis comprises heterogeneous clinical entities that are characterized by the persistence of vascular inflammation after it has served its homeostatic function. Most underlying mechanisms have so far remained elusive. Intravascular immunity refers to the surveillance of the vasculature by leucocytes that sense microbial or sterile threats to vessel integrity and initiate protective responses that entail most events that determine the clinical manifestations of vasculitis, such as end-organ ischaemia, neutrophil extracellular traps generation and thrombosis, leucocyte extravasation and degranulation. Understanding how the resolution of vascular inflammation goes awry in patients with systemic vasculitis will facilitate the identification of novel pharmacological targets and bring us a step closer in each patient to the selection of more effective and less toxic treatments.

Pentraxin 3 as a novel early biomarker for the prediction of Henoch-Schönlein purpura nephritis in children

We investigated the potential role of pentraxin 3 (PTX3) in Henoch-Schönlein purpura (HSP), a common multisystemic vasculitis affecting children, as a predictor of Henoch-Schönlein purpura nephritis (HSPN). A total of 108 cases consisting of 34 children with HSP, 37 children with HSPN, and 37 healthy control children were enrolled in this prospective study from March 2010 to February 2013. Blood and urine samples were collected to measure plasma PTX3, C-reactive protein (CRP), serum creatinine, blood urea nitrogen (BUN), urine microalbumin (MALB), and β2-microglobulin (β2-MG). Median plasma PTX3 concentrations were significantly higher in children with HSPN and HSP than in control subjects before treatment (6.99, 4.18-9.78 ng/ml; 3.19, 1.13-4.27 ng/ml; 1.24, 0.87-2.08 ng/ml, respectively; all p < 0.05). Median plasma PTX3 concentrations were also significantly higher in children with HSPN than in children with HSP before treatment (6.99, 4.18-9.78 vs. 3.19, 1.13-4.27 ng/ml; p < 0.05). After treatment, median plasma PTX3 concentrations significantly decreased in children with HSP (from 3.19, 1.13-4.27 to 1.08, 0.65-2.19 ng/ml; p < 0.05) and HSPN (from 6.99, 4.18-9.78 to 1.29, 1.01-2.26 ng/ml; p < 0.05). Plasma PTX3 concentration was positively correlated with CRP (rho = 0.532, p = 0.001), MALB (rho = 0.606, p < 0.001), β2-MG (rho = 0.490, p = 0.002), and 24-h urinary protein quantity (rho = 0.650, p < 0.001) in children with HSPN. Considering vasculitis, we found that PTX3 could be used as a more efficient potential predictor of HSPN than CRP as indicated by the area under the receiver operating characteristic (ROC) curve (AUCROC) of PTX3 (AUCROC = 0.837; p < 0.001) and CRP (AUCROC = 0.514; p = 0.845). The threshold PTX3 concentration with optimal sensitivity and specificity was 4.30 ng/ml (sensitivity 73.0 %, specificity 79.6 %).

CONCLUSION

PTX3 seems to have an important role in multisystemic vasculitis of HSP, may be involved in the development of HSPN, and used as an early biomarker to predict HSPN.

Making Necrotizing Vasculitis Simple

Background:

Cutaneous necrotizing vasculitides (CNV) represent a heterogeneous group of inflammatory diseases affecting the skin blood vessels, characterized histologically by transmural inflammation of the blood vessel wall with fibrinoid necrosis and clinically characterized by palpable purpura, leading to ulceration. These syndromes represent a spectrum of disease from limited cutaneous small vessel vasculitis to rapidly progressive systemic vasculitis. Moreover, a number of diseases can mimic vasculitis in the skin, thereby presenting diagnostic difficulties for physicians.

Objective:

We present an update of CNV and vasculopathies based on recent literature and clinical experience. We provide a dermatologic approach to the patient presenting with purpura and ischemic skin necrosis focusing on the subtle features that may help physicians discern between primary and secondary causes and the differences between vasculitis and vasculopathy.

Elevated circulating levels and tissue expression of pentraxin 3 in uremia: a reflection of endothelial dysfunction

Elevated systemic pentraxin 3 (PTX3) levels appear to be a powerful marker of inflammatory status and a superior outcome predictor in patients with chronic kidney disease (CKD). As previous data imply that PTX3 is involved in vascular pathology and that adipose tissue mass may influence circulating PTX3 levels, we aimed to study the importance of adipose tissue expression of PTX3 in the uremic milieu and its relation to endothelial dysfunction parameters. Plasma PTX3 and abdominal subcutaneous adipose tissue (SAT) PTX3 mRNA levels were quantified in 56 stage 5 CKD patients (median age 57 [range 25-75] years, 30 males) and 40 age and gender matched controls (median age 58 [range 20-79] years, 27 males). Associations between PTX3 measures and an extensive panel of clinical parameters, including surrogate markers of endothelial function, were assessed. Functional ex vivo studies on endothelial status and immunohistochemical staining for PTX3 were conducted in resistance subcutaneous arteries isolated from SAT. SAT PTX3 mRNA expression correlated with plasma PTX3 concentrations (rho = 0.54, p = 0.0001) and was increased (3.7 [0.4-70.3] vs. 1.2 [0.2-49.3] RQ, p = 0.02) in CKD patients with cardiovascular disease (CVD), but was not significantly different between patients and controls. The association to CVD was lost after adjustments. SAT PTX3 mRNA levels were independently correlated to asymmetric dimethylarginine and basal resistance artery tone developed after inhibition with nitric oxide synthase and cyclooxygenase (rho = -0.58, p = 0.002). Apparent positive PTX3 immunoreactivity was observed in both patient and control arteries. In conclusion, fat PTX3 mRNA levels are associated with measures of endothelial cell function in patients with CKD. PTX3 may be involved in adipose tissue-orchestrated mechanisms that are restricted to the uremic milieu and modify inflammation and vascular complications in CKD patients.

Pentraxin 3, a novel cardiovascular biomarker, is expressed in aortic specimens of patients with coronary artery disease with and without rheumatoid arthritis

BACKGROUND

The aims were to evaluate the presence and extent of pentraxin 3 depositions in specimens from the outer layers of the aorta and from the internal thoracic artery of patients with coronary artery disease with and without rheumatoid arthritis and to search for relationships between pentraxin 3 and vascular inflammation.

METHODS

Using histochemistry and immunohistochemistry, we examined biopsies from the aortic adventitia and from the internal thoracic artery (both with adjacent perivascular tissue), removed during coronary artery bypass grafting in 19 rheumatoid arthritis and 20 non-rheumatoid-arthritis patients, for presence/extent of pentraxin 3 depositions, inflammatory cell infiltrates, and fibrosis.

RESULTS

In the aorta, pentraxin 3 deposition occurred in all specimens, mostly at sites with inflammatory cell infiltrates or fibrosis, and their extent was related to the extent of inflammatory cell infiltrates (rho=0.43, 95% confidence interval: 0.13-0.66, P=.007). The extent of pentraxin 3 and inflammatory cell infiltrates in the aorta was similar in rheumatoid arthritis and non-rheumatoid-arthritis patients, but rheumatoid arthritis patients had more fibrosis and a lower proportion of T-cells in inflammatory cell infiltrates. In the internal thoracic artery, pentraxin 3 occurred only in 36% patients, and inflammatory cell infiltrates and fibrosis occurred in none.

CONCLUSIONS

Pentraxin 3 depositions in the outer aortic layers are common and are related to the local inflammation. On the other hand, they occur less frequently in the internal thoracic artery, i.e., a vessel highly resistant to atherosclerosis. Rheumatoid arthritis patients had more pronounced fibrosis in the aortic specimens and a different leukocytic response than non-rheumatoid-arthritis patients. In theory, pentraxin 3 might modulate the inflammatory process involved in the pathogenesis of cardiovascular disease and represent a target for new therapies.

Blood monocyte chemotactic protein-1 (MCP-1) and adapted disease activity Score28-MCP-1: favorable indicators for rheumatoid arthritis activity

OBJECTIVE

We assessed blood pentraxin 3 (PTX3) and macrophage chemotactic factor-1 (MCP-1) levels as indicators of disease activity in rheumatoid arthritis (RA) patients, because data on disease activity score 28 (DAS28)-erythrocyte sedimentation rate (ESR) and DAS28-C-reactive protein (CRP) are still imperfect.

METHODS

In 111 patients with RA, we examined longitudinal and cross-sectional correlations of blood PTX3, MCP-1, CRP, and ESR levels with measures of clinical arthritic activity, namely, swollen joint count (SJC), tender joint count (TJC), visual analog scale for general health (GH), DAS28, and adapted DAS28-MCP-1.

RESULTS

Blood MCP-1, but not PTX3, was significantly correlated with SJC, TJC, DAS28, and DAS28-CRP. DAS28-MCP-1 was strongly correlated with DAS28 (r  = 0.984, P<0.001) and DAS28-CRP (r  = 0.971, P<0.001), and modestly correlated with CRP (r  = 0.350, P<0.001), and ESR (r  = 0.386, P<0.001). Similarly, the duration of arthritic symptoms, but not sex, was significantly correlated with variables of arthritic activity. In particular, DAS28-MCP-1 significantly correlated with DAS28 during a 6-month period (r  = 0.944, P<0.001; r  = 0.951, P<0.001; r  = 0.862, P<0.001; and r  = 0.865, P<0.001 for month 0, 1, 3, and 6, respectively).

CONCLUSION

Blood MCP-1 and adapted DAS28-MCP-1, but not blood PTX3, may be useful in monitoring RA activity.

Endothelial pentraxin 3 contributes to murine ischemic acute kidney injury

Toll-like receptor 4 (TLR4), a receptor for damage-associated molecular pattern molecules and also the lipopolysaccharide receptor, is required for early endothelial activation leading to maximal inflammation and injury during murine ischemic acute kidney injury. DNA microarray analysis of ischemic kidneys from TLR4-sufficient and -deficient mice showed that pentraxin 3 (PTX3) was upregulated only on the former while transgenic knockout of PTX3 ameliorated acute kidney injury. PTX3 was expressed predominantly on peritubular endothelia of the outer medulla of the kidney in control mice. Acute kidney injury increased PTX3 protein in the kidney and the plasma where it may be a biomarker of the injury. Stimulation by hydrogen peroxide, or the TLR4 ligands recombinant human high-mobility group protein B1 or lipopolysaccharide, induced PTX3 expression in the Mile Sven 1 endothelial cell line and in primary renal endothelial cells, suggesting that endothelial PTX3 was induced by pathways involving TLR4 and reactive oxygen species. This increase was inhibited by conditional endothelial knockout of myeloid differentiation primary response gene 88, a mediator of a TLR4 intracellular signaling pathway. Compared to wild-type mice, PTX3 knockout mice had decreased endothelial expression of cell adhesion molecules at 4 h of reperfusion, possibly contributing to a decreased early maladaptive inflammation in the kidneys of knockout mice. At 24 h of reperfusion, PTX3 knockout increased expression of endothelial adhesion molecules when regulatory and reparative leukocytes enter the kidney. Thus, endothelial PTX3 plays a pivotal role in the pathogenesis of ischemic acute kidney injury.

Different distribution of pentraxin 3 and C-reactive protein in coronary atherosclerotic plaques

AIM

To understand the differences between histopathological characteristics related to PTX3 (pentraxin 3) and CRP (C-reactive protein) in coronary atherosclerotic plaques.

METHODS AND RESULTS

To assess the localization of PTX3 and CRP in coronary plaque, immunohistochemistry was performed using 157 coronary artery specimens from 45 autopsied cases. Overall, immunoreactivity to CRP was more intense than that to PTX3 in lipid rich plaque; however, PTX3 was notably abundant in areas of intraplaque hemorrhage, in which CRP was quite sparse. On quantitative analysis, complicated plaques showed more immunopositive area of PTX3 than fibroatheroma, but with CRP, this trend disappeared. In addition, we examined the phenotype of macrophages in PTX3- and CRP-rich areas using CD163 staining (M2 macrophages). Consequently, these areas were differently characterized by the accumulation of macrophages with high and low magnitude of CD163 positivity, respectively. Next, we immunohistochemically investigated relationships among PTX3, CRP, histological components and clinical presentation in 73 coronary atherectomy specimens obtained from 35 and 38 patients with unstable (UAP) and stable angina pectoris (SAP), respectively. Both PTX3 and CRP were more intense in culprit plaques from patients with UAP than with SAP, and they significantly correlated with CD68 (pan macrophage)-positive areas; however, there was no correlation between PTX3 and CRP.

CONCLUSION

Although PTX3 and CRP were more enhanced in unstable than in stable coronary plaques, their distribution distinctly differed, suggesting that they play distinct biological roles in unstable plaques.

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-1β (IL-1β), 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-1β, 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.

Pentraxin 3(PTX 3): an endogenous modulator of the inflammatory response

Inflammatory or anti-inflammatory? That is the question as far as the acute-phase response and its mediators, the pentraxins, are concerned. Only some ten years ago, the classical or short pentraxin C-reactive protein and the newly discovered long pentraxin PTX3 were considered to exert most of the detrimental effects of acute inflammation, whether microbial or sterile in origin. However, accumulating evidence suggests an at least dichotomous, context-dependent outcome attributable to the pentraxins, if not a straightforward anti-inflammatory nature of the acute-phase response. This paper is focused on the inherent effects of pentraxin 3 in inflammatory responses, mainly in coronary artery disease and in Aspergillus fumigatus infection. Both are examples of inflammatory reactions in which PTX3 is substantially involved; the former sterile, the latter infectious in origin. Apart from different inducing noxae, similarities in the pathogenesis of the two are striking. All the same, the introductory question still persists: is the ultimate impact of PTX3 in these conditions inflammatory or anti-inflammatory, paradoxical as the latter might appear? We try to provide an answer such as it emerges in the light of recent findings.

Long pentraxin 3 (PTX3) in the light of its structure, mechanism of action and clinical implications

Pentraxins are a group of evolutionarily conserved ancient proteins. Depending on their structure, pentraxins are divided into short and long pentraxin families. Pentraxin 3 (PTX3) is the prototype of the long pentraxin group. PTX3 synthesis is stimulated by a variety of molecules involved in the inflammatory process. The inflammatory mediator is typically produced at inflammatory sites; however, it can also be released at the sites remote from the original inflammatory insult. Although mainly expressed by vascular endothelium and smooth muscle cells, PTX3 is also synthesized by myeloid dendritic cells, mononuclear macrophages/phagocytes, vascular endothelial and smooth muscle cells, fibroblasts, adipocytes, cumulus oophorus cells mesangial cells, synovial cells and chondrocytes. PTX3 binds to several ligands including complement component C1q, factor H, ficolin-1 (M-ficolin), mannose-binding lectin, fibroblast growth factor 2, P-selectin, matrix protein TSG6 and Klebsiella pneumoniae; it is also known to play a role in humoral innate immunity as well as in degenerated and apoptotic cells clearance. PTX3 acts as a modulator of inflammatory processes, modifies angiogenesis and atherosclerotic lesion development, and participates in extracellular matrix formation. Due to the fact of PTX3 being primarily produced and released by vascular wall cells, it might be used as a sensitive and independent inflammatory marker.

The long pentraxin PTX3: a modulator of the immunoinflammatory response in atherosclerosis and cardiovascular diseases

Innate and adaptive immune responses participate in atherosclerosis. Pentraxins, an essential component of the humoral arm of innate immunity, are a superfamily of acute phase proteins highly conserved during evolution and can be classified as short pentraxins such as C-reactive protein (CRP) and long pentraxins such as PTX3. The latter has an unrelated, long N-terminal domain coupled to the C-terminal pentraxin domain and differs from CRP in gene organization, cellular source, and recognized ligands. PTX3 in humans, like CRP, is a marker of atherosclerosis and correlates with the risk of developing vascular events. Although CRP sequence and regulation have not been conserved during evolution between mouse and man, the conservation of sequence, gene organization, and regulation of PTX3 in evolution enables one to address the question regarding its pathophysiologic roles in genetically modified mice. Deficiency of PTX3 is associated with increased heart damage with a greater no-reflow area and increased inflammatory response in a model of acute myocardial infarction (MI) caused by coronary artery ligation. More recently, deficiency of PTX3 on an apolipoprotein E knockout background was associated with increased atherosclerosis, macrophage accumulation within the plaque, and a more pronounced inflammatory profile in the vascular wall. Although these observations point to a cardiovascular protective effect of PTX3, they also suggest the possibility that the increased levels of PTX3 in subjects with cardiovascular disease (CVD) may reflect a protective physiologic response that correlates with the severity of the disease. In summary, data that are accumulating suggest that the increase of pentraxins in atherosclerosis could not be regarded as a harmful response but rather a further attempt to protection of our body.

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.

Pentraxin 3 in amniotic fluid: a novel association with intra-amniotic infection and inflammation

OBJECTIVE

Pentraxin 3 (PTX3) is a soluble pattern recognition receptor (PRR) that has an important role in immunoregulation and vascular integrity. The aim of this study was to determine if PTX3 is present in amniotic fluid (AF) and whether its concentration changes with gestational age (GA), in the presence of preterm or term labor, and in cases of intra-amniotic infection/inflammation (IAI) associated with spontaneous preterm labor (PTL) or preterm prelabor rupture of membranes (PROM).

STUDY DESIGN

This cross-sectional study included the following groups: 1) mid-trimester (n=45); 2) uncomplicated pregnancies at term with (n=48) and without (n=40) spontaneous labor; 3) women with PTL and intact membranes who: a) delivered at term (n=44); b) delivered preterm without IAI (n=40); or c) delivered preterm with IAI (n=62); 4) women with preterm PROM with (n=63) and without (n=36) IAI. PTX3 concentration in AF was determined by ELISA. Non-parametric statistics were used for analyses.

RESULTS

1) Among women with PTL and intact membranes, the median AF PTX3 concentration was significantly higher in women with IAI than in those without IAI (7.95 ng/mL vs. 0.38 ng/mL; P<0.001) and than in those who delivered at term (0.55 ng/mL; P<0.001); 2) women with preterm PROM and IAI had a higher median AF PTX3 concentration than those without IAI (9.12 ng/mL vs. 0.76 ng/mL; P<0.001); 3) the median AF PTX3 concentration did not change with GA (mid-trimester: 0.79 ng/mL vs. term not in labor: 0.58 ng/mL; P=0.09); and 4) labor at term was not associated with a significant change of AF PTX 3 concentration (in labor: 0.54 ng/mL vs. not in labor: 0.58 ng/mL, P=0.9).

CONCLUSIONS

PTX3 is a physiologic constituent of the AF, and its median concentration is elevated in the presence of IAI, suggesting that PTX3 may play a role in the innate immune response against IAI.

Pentraxin 3 and complement cascade activation in the failure of arteriovenous fistula

OBJECTIVE

Pentraxin-3 (PTX3) has been suggested to play a role in the development of vascular pathology. Stenosis of arteriovenous fistula (AVF) leading to its failure is the major cause of morbidity in hemodialysis patients. To date, little is known on the pathogenesis of AVF stenosis. The aim of the present study was to investigate the potential role of PTX3 in this setting.

METHODS AND RESULTS

A sample of venous wall was collected at the time of AVF formation in 44 patients with end stage renal disease. Ten patients developed AVF stenosis and from these patients a second portion of the venous wall was obtained during surgical revision of the AVF. Confocal laser scanning microscopy demonstrated that PTX3 immunostaining, hardly detectable in native AVF, was significantly increased in failed AVF, showing a specific co-localization with endothelial cell markers. Circulating mononuclear cells isolated at the time of AVF revision presented a significantly higher PTX3 mRNA expression than those collected during AVF creation. Interestingly, a significant deposition of C5b-9 on endothelial cells, co-localizing with PTX3, was observed in stenotic AVF.

CONCLUSION

The present study demonstrates for the first time a close association between PTX3 deposition and complement activation at the endothelial cell level in failed AVF and suggests a role for PTX3 in modulating innate immunity in the pathogenesis of AVF stenosis.

Translational mini-review series on immunology of vascular disease: mechanisms of vascular inflammation and remodelling in systemic vasculitis

Vessel walls are the primary inflammatory sites in systemic vasculitides. In most cases the initiating event is unknown, and a self-sustaining circuit attracts and activates inflammatory leucocytes in the wall of vessels of various size and anatomical characteristics. Recent studies have revealed homeostatic roles of vascular inflammation and have identified the action of humoral innate immunity, in particular injury-associated signals and acute phase proteins, on the activation of circulating leucocytes, platelets and endothelial cells. These advances have provided clues to the molecular mechanisms underlying the vicious circle that maintains and amplifies vessel and tissue injury.

Increased Serum Pentraxin 3 in Patients with Systemic Sclerosis

Objective.

To determine serum concentrations of pentraxin 3 (PTX3) and its clinical associations in patients with systemic sclerosis (SSc).

Methods.

Serum PTX3 levels from 45 patients with diffuse cutaneous SSc (dSSc), 46 with limited cutaneous SSc (lSSc), and 20 healthy controls were examined by ELISA. PTX3 expression in the sclerotic skin from SSc patients was evaluated immunohistochemically. Normal and SSc fibroblasts were cultured and PTX3 levels in the culture medium were also examined by ELISA.

Results.

Serum PTX3 levels were elevated in patients with SSc relative to controls. PTX3 levels in dSSc patients were significantly higher than in controls and lSSc patients. PTX3 expression in the sclerotic skin from SSc patients was more intense relative to normal skin. Elevation of serum PTX3 levels was associated with more frequent presence of pulmonary fibrosis, cardiac disease, and pitting scar/ulcer and increased serum immunoglobulin levels and erythrocyte sedimentation rates. PTX3 levels correlated positively with modified Rodnan total skin thickness score, and negatively with percentage vital capacity and percentage DLCO in patients with SSc. PTX3 levels also correlated positively with serum levels of 8-isoprostane, a marker of oxidative stress, and hyaluronan, recently identified as an endogenous ligand for Toll-like receptors. PTX3 production from cultured SSc fibroblasts was increased by stimulation with hyaluronan.

Conclusion

These results suggest that elevated serum PTX3 levels are associated with the disease severity of SSc.

The long pentraxin 3 and its role in autoimmunity

OBJECTIVES

To review the physiological and physiopathological roles of pentraxin 3 (PTX3), focusing on autoimmunity and vascular pathology.

METHODS

A systematic literature review using the keywords "pentraxin 3," "innate immunity," "apoptosis," "autoimmunity," and "endothelial dysfunction" from 1990 to 2007 was performed. All relevant articles and pertinent secondary references in English were reviewed.

RESULTS

PTX3 has a large number of multiple functions in different contexts. PTX3 plays an important role in innate immunity, inflammation, vascular integrity, fertility, pregnancy, and also in the central nervous system. In innate immunity, its normal function is to increase the immune response to selected pathogens while also exerting control over potential autoimmune reactions. It maintains a tightly homeostatic equilibrium in the local immune microenvironment by avoiding an exaggerated immune response and controlling peripheral tolerance to self-antigens. In contrast, in some autoimmune diseases, PTX3 appears to be involved in the development of autoimmune phenomena. A possible explanation for these apparent paradoxical functions may be related to the highly polymorphic PTX3 gene.

CONCLUSION

PTX3 is physiologically a protective molecule. However, in several autoimmune diseases PTX3 appears to facilitate the development of autoimmunity. The PTX3 gene could influence the development of autoimmune reactions and vascular involvement in human pathology.

Pentraxins, humoral innate immunity and tissue injury

Tissue damage elicits an inflammatory response, which comprises the rapid synthesis of acute phase molecules. The early local response shapes the resolution of inflammation. Pentraxins are evolutionary conserved soluble pattern recognition receptors, produced in the liver (e.g. C-reactive protein) or at sites of inflammation (the long pentraxin PTX3). Pentraxins behave as flexible adaptors of innate cell functions, complement activation and clearance of cell and matrix debris, regulating tissue hyperplasia and scarring and limiting the risk of autoimmunity associated to unscheduled cell death in vivo.

Role of the soluble pattern recognition receptor PTX3 in vascular biology

Pentraxins act as soluble pattern recognition receptors with a wide range of functions in various pathophysiological conditions. The long-pentraxin PTX3 shares the C-terminal pentraxin-domain with short-pentraxins C-reactive protein and serum amyloid P component and possesses an unique N-terminal domain. These structural features suggest that PTX3 may have both overlapping and distinct biological/ligand recognition properties when compared to short-pentraxins. PTX3 serves as a mechanism of amplification of inflammation and innate immunity. Indeed, vessel wall elements produce high amounts of PTX3 during inflammation and the levels of circulating PTX3 increase in several pathological conditions affecting the cardiovascular system. PTX3 exists as a free or extracellular matrix-associated molecule and it binds the complement fraction C1q. PTX3 binds also apoptotic cells and selected pathogens, playing a role in innate immunity processes. In endothelial cells and macrophages, PTX3 upregulates tissue factor expression, suggesting its action as a regulator of endothelium during thrombogenesis and ischaemic vascular disease. Finally, PTX3 binds the angiogenic fibroblast growth factor-2, thus inhibiting its biological activity. Taken together, these properties point to a role for PTX3 during vascular damage, angiogenesis, atherosclerosis, and restenosis.

Pentraxins in innate immunity: from C-reactive protein to the long pentraxin PTX3

Pentraxins are a family of multimeric pattern-recognition proteins highly conserved in evolution. Based on the primary structure of the subunit, the pentraxins are divided into two groups: short pentraxins and long pentraxins. C-reactive protein and serum amyloid P-component are classic short pentraxins produced in the liver, whereas the prototype of the long pentraxin family is PTX3. Innate immunity cells and vascular cells produce PTX3 in response to proinflammatory signals and Toll-like receptor engagement. PTX3 interacts with several ligands, including growth factors, extracellular matrix components, and selected pathogens, playing a role in complement activation, facilitating pathogen recognition, and acting as a predecessor of antibodies. In addition, PTX3 is essential in female fertility acting on the assembly of the cumulus oophorus extracellular matrix. Thus, PTX3 is a multifunctional soluble pattern recognition receptor acting as a nonredundant component of the humoral arm of innate immunity and involved in tuning inflammation, in matrix deposition and female fertility. Evidence suggests that PTX3 is a useful new serological marker, rapidly reflecting tissue inflammation and damage under diverse clinical conditions.

Granulomatose de Wegener

Wegener's granulomatosis is described by the Chapel Hill nomenclature (1994) as a systemic necrotizing vasculitis affecting small to medium-sized vessels. Cytoplasm-labeling antineutrophil cytoplasmic autoantibodies (cANCA) directed against proteinase 3 (PR3) are detected in the sera of approximately 90% of patients. Reported incidence varies from 2 to 12 cases/million inhabitants/year and prevalence from 24 to 157 cases/million inhabitants, depending on the series. While still rare, incidence seems to have increased slightly over the past few decades. Most new cases involve adults aged 45-60 years. Many of the immune mechanisms involved in its pathogenesis have been identified. These involve cANCA as well as neutrophils, various lymphocyte subtypes, activation molecules, and cytokines. Genetic and environmental factors have been observed in some cases. However, the precise causes of the disease and of the initial immune process leading to cANCA production remain unknown. The most characteristic clinical manifestations are involvement of the upper and lower respiratory tracts and glomerulonephritis. Diffuse/systemic forms may be clinically distinguished from localized/limited forms: the former are mainly associated with vasculitis, and the latter with granulomatous inflammation. Diagnosis relies largely on the combination of characteristic clinical symptoms and cANCA anti-PR3, but histological confirmation should always be obtained when biopsy of affected organs is feasible and safe. Kidney biopsy is particularly useful in cases with renal manifestations, because it also provides some prognostic information. Current recommendations for treatment of systemic forms call first for an induction phase that combines corticosteroids and intravenous cyclophosphamide; the first three pulses are given every 2 weeks and then every 3 weeks until remission is achieved, followed by a maintenance phase with a less toxic immunosuppressant. The optimal duration of this regimen has not yet been determined, but it must certainly not be less than 18 months. Continuation of cotrimoxazole for two additional years is advised once immunosuppressants have been withdrawn. Remission is obtained in more than 85% of the cases to date, but the high relapse rate remains a matter of concern: approximately half of all patients will relapse within the five years following diagnosis. Promising new therapeutic agents, including rituximab, anti-TNF-alpha, and abatacept, are currently under evaluation and may substantially modify management of this disease in the years to come. Today, however, they are reserved for refractory cases.