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Biomedical subjects

N Del Papa

Publications and source records attributed to N Del Papa.

At least 37 records · Page 2Linked to original sources
PubMed1996

Anti-endothelial cell IgG antibodies from patients with Wegener's granulomatosis bind to human endothelial cells in vitro and induce adhesion molecule expression and cytokine secretion.

OBJECTIVE: To elucidate the role of anti-endothelial cell antibodies (AECA) in vascular inflammation in patients with Wegener's granulomatosis (WG). METHODS: IgG fractions from 3 AECA-positive WG patients, IgG from 3 AECA-negative WG patients, and IgG from healthy donors were tested for their ability to: a) bind to endothelial cells and to display complement-dependent or antibody-dependent cellular cytotoxicity, b) modulate cell membrane expression of adhesion molecules, as evaluated by cytofluorometry and by immunoenzymatic assay, and c) induce the secretion of interleukin-1 beta (IL-1 beta), IL-6, IL-8, and monocyte chemotactic protein 1 (MCP-1). RESULTS: We found that AECA IgG from WG patients do not display any significant cytotoxicity but are able to up-regulate the expression of E-selectin, intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 and to induce the secretion of IL-1 beta, IL-6, IL-8, and MCP-1. CONCLUSION: AECA in patients with WG could play a potential pathogenetic role by activating endothelial cells, and thus facilitating leukocyte recruitment and adhesion to endothelial surfaces, rather than by displaying a cytotoxic activity.

Autoantibodies↗
PubMed1996

Antiphospholipid and antiendothelial antibodies.

A lot of attention has recently been paid to antiphospholipid and antiendothelial cell antibodies as serological markers for systemic autoimmune diseases. Antiphospholipid antibodies appear to display a prognostic value for recurrent thrombosis and fetal loss both in a subset of systemic lupus erythematosus and in patients with the primary antiphospholipid syndrome. The range of diagnostic tests for the antiphospholipid syndrome is now becoming larger with the inclusion of assays suitable for identifying antibodies against phospholipids other than cardiolipin and especially against phospholipid-binding proteins. Antiendothelial cell antibodies have been suggested as serological markers for immune-mediated vascular damage. In vitro and in vivo experimental models as well as epidemiological studies seem to support this. However, the assays for their detection still lack standardization.

Animals↗
PubMed1996

In vitro type-1 and type-2 cytokine production in systemic lupus erythematosus: lack of relationship with clinical disease activity.

OBJECTIVE: To investigate the relationship between disease activity and in vitro cytokine, soluble(s)CD23 and polyclonal and anti-DNA antibody production by PBMC from patients with active systemic lupus erythematosus (SLE). METHODS: Cytokines, sCD23 and immunoglobulins were estimated by ELISA in unstimulated and polyclonal mitogen-stimulated culture supernatants. RESULTS: PHA-induced IL-2 and IFN-gamma production were decreased, whereas spontaneous and PHA-induced IL-6 and IL-10 production were increased in cultures of SLE lymphocytes. Conversely, spontaneous and PHA-stimulated IL-4 and sCD23 production was comparable between patients and controls. Finally, we found an increase in in vitro spontaneous polyclonal and anti-DNA IgG secretion. CONCLUSIONS: We demonstrated an expanded type-2 cytokine profile with no correlation with parameters of disease activity.

Adult↗
PubMed1996

Modulation of endothelial cell function by antiphospholipid antibodies.

beta 2-glycoprotein I (beta 2-GP-I) the plasma cofactor for anti-phospholipid antibodies adheres on the endothelial surfaces and can be recognized by anti-beta 2-GP-I antibodies naturally occurring in patients with the anti-phospholipid syndrome. As for the cofactor binding to cardiolipin- or gamma irradiated-plates, the endothelial binding is mediated by the so-called phospholipid binding site, a cationic structure able to react with anionic molecules. Endothelial monolayers appear to represent a substrate able to bind beta 2-GP-I and to present it in a suitable manner in order to allow the binding of anti-beta 2-GP-I beta 2 antibodies. The complex between beta 2-GP-I and the respective antibodies induce an endothelial cell activation as demonstrated by the up-regulation of adhesion molecule expression, the secretion of proinflammatory cytokines and the modulation of arachidonic acid metabolism. Taken together these findings strongly sustain a pivotal role for beta 2-GP-I in allowing antibody deposition on the endothelium and in affecting endothelial cell functions potentially responsible for a procoagulant state.

Antibodies, Antiphospholipid↗
PubMed1995

Anti-beta 2-glycoprotein I antibodies: a marker of antiphospholipid syndrome?

Anticardiolipin (aCL) and anti-beta 2-glycoprotein I(anti beta 2GPI) antibodies have been shown in animal models as not cross-reacting antibody populations. This observation prompted us to prove if anti-beta 2GPI exist in human sera by using a reliable method and then to investigate if these are independent from aCl antibodies. We have developed a new ELISA for the detection of anti-beta 2GPI antibodies employing the coating of the protein in carbonate buffer to irradiated microtitre plates and the filtration of serum samples, that makes irrelevant the binding to the uncoated wells. IgG F(ab)2 fragments from IgG positive sera were shown bind beta 2GPI, providing that the binding was a specific antibody binding, mediated by the antigen binding site of the antibody molecule: moreover the antibodies were not able to differentiate native and delipidated beta 2GPI coated plates, making a possible role of a phospholipid contaminant unlikely. On the other hand, the phosphorus content of native as well as delipitated beta 2GPI was undetectable. IgG, but not IgM, anti-beta 2GPI antibodies were classically inhibited by the addition of soluble beta 2GPI, while cardiolipin liposomes appear to modify the reaction in a completely different way, possibly by the described interaction between cardiolipin and beta 2GPI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Characterization of the endothelial surface proteins recognized by anti-endothelial antibodies in primary and secondary autoimmune vasculitis.

The antigenic structures recognized by anti-endothelial cell antibodies (AECA) in sera from 10 Wegener's granulomatosis (WG) and 12 systemic lupus erythematosus (SLE) patients with signs of vasculitis were characterized by immunoprecipitation of selectively radiolabeled surface membrane proteins from human umbilical vein endothelial cells. Electrophoretic analysis of the immunoprecipitated proteins revealed reactivities against endothelial antigens ranging in size from 200 to 25 kDa. AECA antigens were not cell specific, since the same sera also reacted, at least in part, with radiolabeled human fibroblast surface proteins. The majority of WG patients displayed a constant precipitation pattern of five proteins (180, 155, 125, 68, and 25 kDa). On the contrary, AECA from SLE sera reacted with a more heterogeneous series of endothelial proteins. A group of four proteins, however, was also found in the majority of SLE sera: 200, 180, 155, and 25 kDa. In addition, some endothelial antigens were immunoprecipitated only by WG (125 kDa) or by SLE sera (200 kDa), suggesting a different endothelial reactivity in different vasculitic processes. The reaction did not involve intracellular proteins as demonstrated by the lack of reactivity of SLE sera negative for AECA but positive for anti-cytoplasmic or anti-nuclear antibodies. These data confirming that AECA recognize surface endothelial determinants further support a potential pathogenetic role for these antibodies in autoimmune vasculitis.

Antibodies↗
PubMed1994

Beta 2 glycoprotein I and placental anticoagulant protein I in placentae from patients with antiphospholipid syndrome.

OBJECTIVE: To investigate the immunohistological distribution of beta 2-glycoprotein I (beta 2 GPI) and placental anticoagulant protein I (PAP-I) in normal and pathological placentae of patients with antiphospholipid (aPL) antibody associated recurrent fetal loss. These proteins are 2 natural anticoagulants able to interfere with aPL antibody binding. METHODS: Placentae from 4 patients with primary antiphospholipid antibody syndrome (pAPS), from 2 patients with aPL negative systemic lupus erythematosus (SLE) and from 7 healthy women were studied. Cryostatic placental sections were tested by indirect immunofluorescence using polyclonal anti-PAP-I and anti-beta 2GPI antisera as well as purified IgG and anti-beta 2GPI monoclonal antibody. The same tissue sections were also tested by direct immunofluorescence with FITC-F(ab)2 goat antihuman IgG. RESULTS: We found that (a) the placental distribution of PAP-I was comparable in normal and pathological specimens; (b) on the contrary, increased beta 2GPI deposition was present on the trophoblast surfaces of placentae obtained from patients with persistent raised titers of aPL antibodies. Comparable IgG deposition on villi surface was also found in aPL positive but not in control placentae. CONCLUSION: Our data are consistent with the hypothesis that high titer aPL binds to a beta 2GPI phospholipid complex in placentae of women with recurrent fetal loss but that a quantitative deficiency of PAP-I does not play a pathogenetic role in aPL associated fetal loss.

Adult↗
PubMed1992

Enrichment of IgG anti-DNA-producing lymphoblastoid cell lines by antigen-coated immunomagnetic beads.

In this paper we describe the establishment of four anti-DNA-producing lymphoblastoid cell lines (LCL) by Epstein-Barr virus (EBV) infection of peripheral blood B-cells from a patient with systemic lupus erythematosus. The LCL showed a heterogeneous cell composition: the frequencies of cells in active proliferation, cells secreting IgG or IgM, and cells effectively producing IgG or IgM anti-DNA were estimated by limiting dilution analysis. The cells producing anti-DNA antibodies were a small fraction of the whole cell population constituting the LCL. In order to enrich the fraction of cells producing the desired antibody we performed a positive selection by DNA-coated immunomagnetic beads. Results show that in two out of three IgG anti-DNA-secreting LCL the frequency of DNA-producing cells increased after incubation with DNA-coated beads. At variance, IgM anti-DNA-secreting cells were completely lost after immunomagnetic separation. This approach could represent a further tool to obtain better fusion partners to construct stable hybrids secreting human monoclonal antibodies. The advantages of the presented technique would be: (a) removing of the fraction of low-affinity IgM-producing cells, which is often prevalent in EBV-induced LCL; and (b) the enrichment of IgG anti-DNA producing cells, which better represent the antibodies involved in the pathogenesis of the disease.

Adult↗
PubMed1992

In vitro and ex vivo effect of tiaprofenic acid on human peripheral blood mononuclear cells.

The effect of the non-steroidal anti-inflammatory drug (NSAID) tiaprofenic acid on different human immune parameters was investigated in vitro or following in vivo administration in healthy adult volunteers. Results from the in vitro study demonstrated an increased mitogen-induced blastogenesis and interleukin 2 (IL-2) production together with a reduced polyclonal immunoglobulin (Ig) secretion in the presence of the drug. Results from the ex vivo study showed that treatment with tiaprofenic acid had no significant effects on the immune parameters investigated, i.e. unstimulated and mitogen-induced proliferation and IL-2 production, spontaneous and stimulated Ig synthesis, lymphocyte subpopulations, serum Ig and complement levels.

Adult↗
PubMed1990

In vitro modulation of human endothelial cell growth by Kaposi's sarcoma sera.

Sera from patients affected either by the classic/Mediterranean form (5 patients) and human immune deficiency virus (HIV)-associated (12 patients) form of Kaposi's sarcoma (KS) were compared in supporting endothelial cell in-vitro proliferation. Healthy blood donors (15) and a group of 7 HIV-positive drug addicts with no dermatological involvement were used as control groups. Endothelial cell growth was assessed by means of a [3H]thymidine incorporation and by an optical density direct cell-counting assay. Our results indicate that, at the highest concentrations, sera obtained from patients affected by KS with no sign of HIV infection induced significantly higher levels of endothelial cell proliferation when compared with HIV-associated KS and with normal controls. This growth-promoting activity was apparently cell selective, being present in endothelial cell but not in fibroblast cultures.

Cell Count↗
PubMedDate not supplied

[Anti-chromatin antibodies in juvenile rheumatoid arthritis].

OBJECTIVE: to evaluate the prevalence and clinical significance of anti-chromatin antibodies (Abs) in juvenile rheumatoid arthritis (JRA). METHODS: IgG anti-chromatin Abs were detected by an enzyme-linked immunosorbent assay (ELISA), in sera of 94 children with JRA (10 children with systemic, 38 with polyarticular and 46 with oligoarticular disease onset). As control group, 33 age- and-sex-matched healthy children (HC) were also examined. RESULTS: Abs to chromatin were detected in 24/94 (25.5%) of children suffering from JRA. Particularly, the higher prevalence of anti-chromatin Abs has been found in children with oligoarticular (30,4%) and polyarticular (23.7%) onset JRA. In these groups Abs titers were significantly higher compared to systemic JRA and HC (p=0.003). Anti-chromatin Abs were observed more frequently in patients with oligoarticular disease and chronic uveitis (21.7%). Furthermore, higher levels of anti-chromatin Abs has been found in all the patients treated with anti-TNF-alpha therapy (p< 0.0001). CONCLUSIONS: our results confirm previous data about the prevalence of anti-chromatin Abs in JRA. These Abs were significantly higher in the group of patients with oligoarticular onset with past or present history of ocular involvement and in the group with polyarticular JRA treated with biologic therapy. A long-term follow-up study could be useful to evaluate the potential utility of these autoantibodies.

Arthritis, Rheumatoid↗
PubMedDate not supplied

[Endothelial progenitor cells in systemic sclerosis: their possible role in angiogenesis].

BACKGROUND: Recently, several studies have demonstrated the presence of circulating endothelial progenitors (CEPs) responsible for angiogenesis. Notably, these cells are able to migrate to ischemic tissues and differentiate in situ in mature endothelial cells. Aim of this study was to assess the presence of CEPs in the peripheral blood of patients with Sistemic Sclerosis (SSc) and evaluate their significance as an attempt of re-vascularization MATERIAL AND METHODS: Samples of peripheral blood from 40 healthy subjects and 56 patients with SSc were studied. Five-parameter, 3-color flow cytometry was performed with a FACScan. CEPs were defined as CD45 negative, CD34 and CD133 positive. In addition, plasma levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were detected by commercial ELISA (R&D Systems). RESULTS: Levels of CEPs (CD133+/CD34+/CD45-) were significantly higher in patients with SSc in comparison to HC (P = 0.01). No correlation was found between CEPs and any clinical parameter of disease neither activity score. CEPs were significantly higher in the group of patients with early disease, while their number decreased in the late phases of disease. Plasma levels of VEGF, but not bFGF, were significantly higher in SSc in comparison to HC (P<0.001) but no correlation was found between VEGF concentrations and CEP number. CONCLUSIONS: The presence of CEPs in patients with SSc suggest that sclerodermic hypoxic tissues could induce the mobilization of bone-marrow derived cells in an attempt to provided new vessels, in the early phase of the disease, at least.

Adult↗
PubMedDate not supplied

[Raised levels of circulating endothelial cells in systemic sclerosis].

OBJECTIVE: Circulating endothelial cells (CECs) have been described in different conditions with vascular injury. Vascular abnormalities play a key role in the pathogenesis of Systemic Sclerosis (SSc). The aim of our study was to look for the presence of CECs in SSc patients and to evaluate their clinical significance. METHODS: We studied 52 SSc patients and 40 healthy controls (HC). Five-parameter, 3-color flow cytometry was performed with a FACScan. CECs were defined as CD45 negative, CD31 and P1H12 positive, and activated CECs as CD45 negative and P1H12, CD62, or CD106 positive. RESULTS: Total and activated CEC counts were significantly higher in SSc patients when compared with HC and positively correlated with disease activity score. We found a significant association between CECs and disease activity; as regard with organ involvement, CEC number correlate with the severity of pulmonary hypertension. CONCLUSIONS: Raised counts of CECs may represent direct evidence of active vascular disease in SSc as regard as visceral involvement, the association between CECs and pulmonary hypertension suggest a relevant role for CECs as a marker of prominent endothelial involvement.

Adult↗