Maria Grazia Sabbadini

PTX3 in small‐vessel vasculitides: An independent indicator of disease activity produced at sites of inflammation

OBJECTIVE To verify whether the prototypical long pentraxin PTX3 represents an indicator of the activity of small-vessel vasculitis. METHODS Concentrations of PTX3, a pentraxin induced in endothelium by cytokines, were measured by enzyme-linked immunosorbent assay in the sera of 43 patients with Churg-Strauss syndrome, Wegeners granulomatosis, and microscopic polyangiitis. PTX3 was also measured in the sera of 28 patients with systemic lupus erythematosus (SLE), 22 with rheumatoid arthritis, and 16 with CREST syndrome (calcinosis, Raynauds phenomenon, esophageal dysmotility, sclerodactyly, telangiectasias). Serum concentrations of C-reactive protein (CRP) were measured by immunoturbidimetry. The cells involved in PTX3 production in vivo were identified in skin biopsy samples. RESULTS Patients with active vasculitis had significantly higher concentrations of PTX3 than did those with quiescent disease (P < 0.001). PTX3 levels in the latter group were similar to those in healthy controls. PTX3 levels were higher in patients with untreated vasculitis and lower in patients who underwent immunosuppressive treatments (P < 0.005). In contrast, patients with active SLE had negligible levels of the pentraxin. PTX3 levels did not correlate with CRP levels in vasculitis patients. Endothelial cells produced PTX3 in active skin lesions. CONCLUSION PTX3 represents a novel acute-phase reactant produced at sites of active vasculitis.

Cutting Edge: Dissociation Between Autoimmune Response and Clinical Disease After Vaccination with Dendritic Cells

Autoimmunity represents a caveat to the use of dendritic cells (DCs) as adjuvant for human vaccines. We derived DCs from normal BALB/c mice or from mice prone to autoimmunity (NZB × NZW) F1. We allowed DCs to phagocytose apoptotic thymocytes and vaccinated syngeneic animals. All mice developed anti-nuclear and anti-dsDNA Abs. Autoantibodies in normal mice were transient, without clinical or histological features of autoimmunity or tissue involvement. In contrast, autoimmunity was maintained in susceptible mice, which underwent renal failure and precociously died. The data suggest that DC vaccination consistently triggers autoimmune responses. However, clinical autoimmunity develops in susceptible subjects only.

Delayed clearance of apoptotic lymphoma cells allows cross-presentation of intracellular antigens by mature dendritic cells

Single cells are deleted from the midst of living tissue during normal turnover and embryogenesis. This event is not associated with inflammation or autoimmunity. Little is known of the clearance of apoptotic cells during dangerous situations, accompanied by extensive cell death and tissue damage: when macrophages are overwhelmed by apoptotic cells, other phagocytes, including immature dendritic cells (DCs), may become involved. DCs efficiently present antigens derived from the processing of internalized apoptotic bodies to class I‐ and class II‐restricted T cells. Antigen presentation results either in T cell activation or in their functional blockade. The outcome is influenced by pro‐inflammatory maturative signals: efficient T cell cross‐priming requires fully mature DCs. Here we discuss in vitro data suggesting that the number of apoptotic cells that die at a given time influences DC maturation and therefore their ability to uptake antigens from apoptotic cells and cross‐activate T lymphocytes. J. Leukoc. Biol. 66: 345–349; 1999.

Pentraxin-3 as a Marker of Disease Activity in Takayasu Arteritis

BACKGROUND Because pentraxin-3 (PTX3) is produced by immune and vascular cells in response to proinflammatory signals, it may be a useful biomarker for defining disease activity in patients with Takayasu arteritis. OBJECTIVE To compare PTX3 levels in patients who have Takayasu arteritis with those in healthy and infected controls, and to compare accuracy of PTX3 levels with that of C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR) for distinguishing active and inactive disease. DESIGN Cross-sectional, noninterventional study conducted between September 2005 and October 2008. SETTING Immunology and rheumatology clinic at a university hospital in Italy. PATIENTS 57 consecutive patients with Takayasu arteritis and known disease activity, 57 healthy blood donor controls, and 15 patients with acute infection. MEASUREMENTS Disease activity by clinical criteria; plasma PTX3 and CRP levels and ESR. RESULTS 27 patients had active Takayasu arteritis; 30 had inactive disease. Levels of PTX3 were higher in patients with active disease (median, >2.14 ng/mL [range, 0.57 to 48.18 ng/mL]) than in those with inactive disease (median, 0.63 ng/mL [range, 0.00 to 1.64 ng/mL]) and were higher than in healthy patients (median, 0.11 ng/mL [range, 0 to 1.20 ng/mL]) or those with acute infection (median, 0.26 ng/mL [range, 0 to 0.75 ng/mL]). A plasma PTX3 level greater than 1 ng/mL was more accurate than normal thresholds of CRP or ESR for distinguishing active from inactive disease. LIMITATION The study excluded patients with unknown or equivocal disease status. CONCLUSION Plasma levels of PTX3 could help distinguish active from inactive Takayasu arteritis but should not be adopted for clinical use until the findings are confirmed in a broader spectrum of patients whose disease activity is unknown or equivocal before testing.

Plasma and tissue expression of the long pentraxin 3 during normal pregnancy and preeclampsia

OBJECTIVE: Cell death normally occurs during pregnancy and is critical during its common complication, preeclampsia. The long pentraxin 3 (PTX3) gene is generated in tissues that cope with excessive or deregulated cell death and inhibits the cross-presentation of cell-associated antigens. We examined whether PTX3 is expressed during pregnancy and possibly involved in the development of preeclampsia. METHODS: Women with preeclampsia (n = 30), women with uncomplicated pregnancies (n = 66), age-matched healthy women (n = 50), women who developed acute bacterial infections (n = 20), and women with rheumatoid arthritis (n = 20) were studied. The concentrations of PTX3 were measured in the blood by a sandwich enzyme-linked immunosorbent assay (ELISA) and in placentas by immunohistochemistry. The concentrations of PTX3 and C-reactive protein in the various groups were compared by nonparametric tests (the Mann-Whitney U and the Kruskal-Wallis tests). The odds of developing preeclampsia were assessed using logistic regression. RESULTS: PTX3 was expressed in amniotic epithelium and chorionic mesoderm, trophoblast terminal villi, and perivascular stroma in placentas from pregnancies of uncomplicated subjects. Circulating levels steadily rose during normal gestation and peaked during labor. Serum levels of PTX3 were strikingly higher in preeclampsia compared with normal control pregnancies (5.08 ± 1.34 and 0.59 ± 0.07 ng/mL, respectively, P < .001). Sites of higher expression in the placentas from preeclamptic patients include infarcts and fibrinoid zones. CONCLUSION: Defects in the homeostatic response to cell death/remodeling events, revealed by enhanced levels of PTX3, could be implicated in preeclampsia. LEVEL OF EVIDENCE: II-2

The multifaceted clinical presentations and manifestations of Erdheim–Chester disease: comprehensive review of the literature and of 10 new cases

Objectives Erdheim–Chester disease (ECD) is a rare inflammatory disorder characterised by organ infiltration by non-Langerhans’ histiocytes. Although rare, ECD is clearly an overlooked diagnosis. No data specifically addressing the most frequent presentations of ECD at the time of onset in a large cohort of patients are currently available. Methods We reviewed all the published cases in the English literature of histologically-confirmed ECD. We excluded reports in which data regarding onset and diagnosis were not univocal, as well as repeated reports of the same case(s). We also included in the analysis 10 new unpublished patients from our cohort. We analysed the disease presentation with particular regard to the manifestations that induced patients to seek medical attention and their subsequent evolution. Results In the cumulative cohort of 259 cases, ECD predominantly presented with skeletal symptoms, diabetes insipidus, neurological and constitutional symptoms. Diabetes insipidus and constitutional symptoms, if not present at onset, seemed to only seldom develop. There were differences in ECD presentation and course among different age groups of patients. Conclusions Physicians should be aware of the extraordinarily heterogeneous clinical presentations and manifestations of ECD in order to include ECD in the differential diagnosis of several conditions.

Treatment of Refractory Takayasu Arteritis with Tocilizumab: 7 Italian Patients from a Single Referral Center

Objective. The aim of our study was to evaluate the safety and the efficacy of tocilizumab (TCZ) for refractory Takayasu arteritis (TA). Methods. We retrospectively assessed the outcome of blocking interleukin (IL)-6 with TCZ in 7 consecutive patients with refractory TA using a combination of clinical and imaging assessment. Results. During a median followup visit at 14 months, 4 patients taking TCZ [including 2 nonresponders to tumor necrosis factor (TNF) inhibitors] achieved clinical response, suggesting a nonredundant role for IL-6 in TA. Inflammatory markers normalized in all patients treated with TCZ. However, vascular progression occurred in 4 patients, suggesting the involvement of other inflammatory pathways and confirming the limitations of erythrocyte sedimentation rate and C-reactive protein for disease activity assessment while taking TCZ. Three patients experienced adverse events and 2 suspended TCZ. Conclusion. TCZ may be effective in a subset of patients with refractory TA, even in cases of unresponsiveness to TNF inhibitors. Inflammatory markers are not valid markers of TA activity on TCZ. Further studies are needed to confirm these preliminary observations.

Circulating platelets as a source of the damage-associated molecular pattern HMGB1 in patients with systemic sclerosis

The link between platelet activation and vascular injury in Systemic Sclerosis (SSc) is poorly characterized. Here we report that platelet activation results in i) the translocation from the cytoplasm to the surface of HMGB1, a prototypical DAMP signal associated with tissue regeneration and ii) the release of platelet derived microparticles (PDμP) expressing HMGB1. Decreased HMGB1 content (334.6 ± 21.2 vs 587.1 ± 11.1 AUF, P < 0.001) and HMGB1 translocation to the outer leaflet of the plasma membrane (17.8 ± 3.5 vs 4.5 ± 0.5%, P < 0.001) characterize circulating platelets of SSc patients (n = 29) when compared with age-matched healthy controls (HC, n = 20). Conversely, a significantly higher fraction of PDμP in the blood of SSc patients, but not of HC, consistently expose (HMGB1 (MFI 62.8 ± 3.95 vs 4.3 ± 0.7). Platelet HMGB1 depletion is significantly associated in SSc patients with degranulation and with expression of P-selectin and of tissue factor as well as with fibrinogen binding to their plasma membrane. These findings indicate that platelets represent a source of HMGB1, an ancestral signal of necrosis, in the vasculature of SSc patients, possible contributing to persistent microvascular injury and endothelial cell activation.

BRAFV600E-mutation is invariably present and associated to oncogene-induced senescence in Erdheim-Chester disease

Objectives Erdheim-Chester disease (ECD) is a rare form of histiocytosis characterised by uncontrolled chronic inflammation. The oncogenic BRAFV600E mutation has been reported in biopsies in 19 out of 37 patients with ECD from the largest published cohort, but never found in the patients’ peripheral blood. Also, the role of the mutation in the pathogenesis of the disease has not been elucidated yet. BRAFV600E has been associated with oncogene-induced senescence (OIS), a protective mechanism against oncogenic events, characterised by the induction of proinflammatory pathways. Methods We verified the BRAF status in biopsies and peripheral blood from 18 patients with ECD from our cohort and matched controls by means of immunohistochemistry and of an ultrasensitive assay, based on the combination of a locked nucleic acid PCR and pyrosequencing. Droplet digital PCR was used to confirm the findings. We also evaluated the presence of senescence markers in ECD histiocytes. Results BRAFV600E mutation was present in all the biopsy and peripheral blood samples from patients with ECD and in none of the controls. ECD histiocytes and a fraction of circulating monocytes from patients with ECD showed signs of a constitutive activation of the MAPK pathway. Moreover, BRAF-mutated histiocytes expressed markers of OIS. Conclusions The oncogenic BRAFV600E mutation is present in biopsies and in the peripheral blood from all patients with ECD who were evaluated and is associated with OIS. These findings have significant implications for the pathogenesis, diagnosis and treatment of ECD.

Efficacy of traditional and biologic agents in different clinical phenotypes of adult-onset Still's disease

OBJECTIVE To evaluate the efficacy of antiinflammatory agents, steroids, immunosuppressants, and biologic agents in patients with adult-onset Stills disease (AOSD) who have either chronic articular disease or nonchronic disease. METHODS Forty-five patients with AOSD were seen and followed up for at least 2 years at our institution, from 1991 to 2008. The majority of patients were treated with several therapeutic regimens; a total of 152 efficacy trials were administered. Data regarding the type of medication, the dosage used, and the outcome of these trials were collected and analyzed. RESULTS Our data showed that the efficacy of monotherapy with a nonsteroidal antiinflammatory drug was very low (16%) and confirmed good efficacy of steroid therapy (63%), particularly in patients without chronic articular disease (78%). Patients whose disease did not respond to steroid therapy at the time of disease onset were at risk of the subsequent development of chronic arthritis. Disease-modifying antirheumatic drug (DMARD) monotherapy was successful in controlling steroid-resistant or steroid-dependent disease in 60% of patients. Methotrexate and cyclosporine showed the best response rates. The combination of high-dose steroids and cyclosporine was administered to successfully control some acute life-threatening complications. Only 6 patients had disease that was both steroid resistant and DMARD resistant. Treatment with biologic agents eventually led to satisfactory control of disease manifestations in 5 (83%) of these 6 patients. CONCLUSION Steroids were less effective in patients with chronic articular disease than in those with nonchronic disease. The administration of DMARDs early after disease onset could be beneficial in patients with steroid-resistant disease who are at risk of the development of chronic articular disease. Biologic agents proved to be highly effective in both steroid-resistant and DMARD-resistant AOSD.