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Biomedical subjects

A Tincani

Publications and source records attributed to A Tincani.

At least 55 records · Page 3Linked to original sources
PubMed2001

Statins prevent endothelial cell activation induced by antiphospholipid (anti-beta2-glycoprotein I) antibodies: effect on the proadhesive and proinflammatory phenotype.

OBJECTIVE: To investigate the ability of statins, the inhibitors of the hydroxymethylglutaryl-coenzyme A reductase enzyme, to affect endothelial cell activation induced by anti-beta2-glycoprotein I (anti-beta2GPI) antibodies in vitro. METHODS: Human umbilical vein endothelial cell (HUVEC) activation was evaluated as U937 monocyte adhesion, E-selectin, and intercellular adhesion molecule I (ICAM-1) expression by cell enzyme-linked immunosorbent assay and as interleukin-6 (IL-6) messenger RNA (mRNA) expression by RNA protection assay. E-selectin-specific nuclear factor kappaB (NF-kappaB) DNA-binding activity was evaluated by the gel-shift assay. HUVECs were activated by polyclonal affinity-purified IgG, human monoclonal IgM anti-beta2GPI antibodies, human recombinant IL-1beta, tumor necrosis factor alpha, or lipopolysaccharide (LPS). RESULTS: Fluvastatin reduced, in a concentration-dependent manner (1-10 microM), the adhesion of U937 to HUVECs and the expression of E-selectin and ICAM-1 induced by anti-beta2GPI antibodies as well as by cytokines or LPS. Another lipophilic statin, simvastatin, displayed similar effects but to a lesser extent than fluvastatin. The inhibition of E-selectin expression exerted by fluvastatin was related to the impairment of NF-kappaB binding to DNA. Moreover, the drug attenuated the expression of IL-6 mRNA in HUVEC exposed to anti-beta2GPI antibodies or cytokines. Incubation of HUVECs with mevalonate (100 microM), concomitantly with fluvastatin, greatly prevented the inhibitory effect of statin. CONCLUSION: Endothelial activation mediated by anti-beta2GPI antibody can be inhibited by statins. Because of the suggested role of endothelial cell activation in the pathogenesis of antiphospholipid syndrome (APS), our data provide, for the first time, a rationale for using statins as an additional therapeutic tool in APS.

Antibodies, Antiphospholipid↗
PubMed2001

Antiphospholipid antibodies and the endothelium.

The interaction between aPL (particularly anti-beta 2GPI antibodies) and endothelium does represent a potential pathogenetic mechanism for the thrombotic manifestations of the syndrome. The autoantibody-mediated EC activation probably plays a role in sustaining the appearance of a proadhesive, proinflammatory, and procoagulant phenotype. The heterogeneity of the APS clinical manifestations is likely linked to the varied effects that aPL can induce on ECs and to the different functions that ECs display depending on the anatomic localization.

Antibodies, Antiphospholipid↗
PubMed2001

Anti-C1q antibodies may help in diagnosing a renal flare in lupus nephritis.

It is still uncertain which, if any, immunologic parameters may help diagnose a renal flare of lupus nephritis. Anti-C1q antibody (Ab) titers have been elevated in patients with lupus with renal involvement, but little information is available on whether the titers are different in quiescent and active phases of lupus nephritis. In this study, we compared anti-C1q Ab titers with other serological test results in 48 patients with biopsy-proven lupus nephritis to assess which parameter could offer the best reliability for differentiating between quiescent and active phases of lupus nephritis. Serum C3 and C4 levels, as well as anti-double-stranded DNA, antiendothelial cell, anti-C1q, and antiphospholipid Ab titers, were evaluated in patients with quiescent renal disease (38 samples) and those with clinical evidence of renal activity (23 samples). Only anti-C1q Ab titers correlated with active renal disease in both univariate (P < 0.0001) and multivariate analysis (P < 0.0001), with a sensitivity of 87% and a specificity of 92%. In six patients, immunologic parameters were measured serially. In all patients, the high anti-C1q Ab titers returned to normal values after treatment-induced remission. The other serological parameters did not show a significant association with renal disease activity. In patients with biopsy-proven lupus nephritis, anti-C1q Ab titers appear to be strongly related to renal disease activity. Their measurement may be useful for confirming the diagnosis of renal flares of lupus nephritis.

Adult↗
PubMed2001

Anticardiolipin antibody assay: a methodological analysis for a better consensus in routine determinations--a cooperative project of the European Antiphospholipid Forum.

Despite the widely recognized practical importance of anticardiolipin (aCL) ELISA, the reliability of this test has been recently discussed. In order to investigate this area on European scale, we sent to 30 experienced centers a questionnaire focusing on the diagnostic procedures applied to patients with antiphospholipid syndrome (APS) and on the detailed protocols used to perform aCL. Anticardiolipin ELISA was found to be the most frequently performed test in patients with suspected APS, but significant difference was shown among the various protocols. The cross-laboratory multiple examination of ten serum samples evaluated independently by the 24 centers pointed out the difficulty in getting comparable results. Therefore a "consensus" protocol was derived from the aCL methods giving the best performance. The materials and reagents necessary to perform the "consensus" method, including, as putative standards, one IgG and one IgM monoclonal antibody (HCAL and EY2C9) were distributed to 19 Centers. The results of one IgG and one IgM aCL high positive sera measured in serial dilutions were compared. A progressive decrease in the variability of the values obtained for a given sample appeared evident when all the laboratories used the same standard, in their own in-house ELISA and even more in the "consensus" ELISA. Our data show that aCL ELISA standardization is necessary in order to obtain comparable results in different laboratories.

Adult↗
PubMed2001

Anti-beta2 glycoprotein I antibodies cause inflammation and recruit dendritic cells in platelet clearance.

Scavenger phagocytes are mostly responsible for the in vivo clearance of activated or senescent platelets. In contrast to other particulate substrates, the phagocytosis of platelets does not incite proinflammatory responses in vivo. This study assessed the contribution of macrophages and dendritic cells (DCs) to the clearance of activated platelets. Furthermore, we verified whether antibodies against the beta2 Glycoprotein I (beta2GPI), which bind to activated platelets, influence the phenomenon. DCs did not per se intemalise activated platelets. In contrast, macrophages efficiently phagocytosed platelets. In agreement with the uneventful nature of the clearance of platelets in vivo, phagocytosing macrophages did not release IL-1beta, TNF-alpha, or IL-10, beta2GPI bound to activated platelets and was required for their recognition by anti-beta2GPI antibodies. DCs internalised platelets opsonised by anti-beta2GPI antibodies. The phagocytosis of opsonised platelets determined the release of TNF-alpha and IL-1beta by DCs and macrophages. Phagocytosing macrophages, but not DCs, secreted the antiinflammatory cytokine IL-10. We conclude that anti-beta2GPI antibodies cause inflammation during platelet clearance and shuttle platelet antigens to antigen presenting DCs.

Antibodies↗
PubMed2000

Antiphospholipid antibodies affect trophoblast gonadotropin secretion and invasiveness by binding directly and through adhered beta2-glycoprotein I.

OBJECTIVE: To investigate the in vitro ability of antiphospholipid antibodies (aPL) to bind human trophoblast cells and to affect gonadotropin secretion and invasiveness. METHODS: Antiphospholipid antibody IgG from women with recurrent miscarriages, beta2-glycoprotein I (beta2GPI)-independent IgG aPL human monoclonal antibody (mAb) (519), and IgM anti-beta2GPI human mAb (TMIG2) were investigated for their binding to trophoblasts cultured for various amounts of time, their ability to affect invasiveness of Matrigel-coated filters, and their release of human chorionic gonadotropin (hCG). RESULTS: Polyclonal IgG aPL, as well as mAb 519 and TMIG2, bound to trophoblasts, the highest binding being found when cells displayed the greatest amount of syncytium formation. TM1G2 binding was found to be betaGPI dependent. Both polyclonal and monoclonal aPL, but not the controls, significantly reduced hCG release and Matrigel invasiveness. CONCLUSION: These findings suggest that aPL recognition of both anionic PL and adhered beta2GPI on trophoblast cell structures might represent a potential pathogenetic mechanism for defective placentation in women with the antiphospholipid syndrome.

Anions↗
PubMed2000

Anti-beta2 glycoprotein I antibodies prevent the De-activation of platelets and sustain their phagocytic clearance.

Exposure to phosphatidylserine (PS) tags dying and senescent cells for removal and identifies activated platelets. In this study we followed the fate of PS-exposing platelets in the presence of antibodies purified from Systemic Lupus Erythematosus (SLE) and primary Anti-phospholipid Syndrome (APS) patients' sera by beta2GPI affinity chromatography. Thrombin-activated platelets exposed PS and associated to beta2GPI. Both events were required for recognition by antibodies. Human monocyte-derived macrophages phagocytosed activated platelets only. Each macrophage internalized an average of 3.16+/-0.2 platelets after 60 min at 37 degrees C. Phagocytosis did not increase after longer incubations (4.65+/-0.26 platelets internalized by each macrophage after 300 min). Recognition of platelets by anti-beta2GPI antibodies significantly increased phagocytosis (P< 0.01). Upon withdrawal of thrombin, platelets downregulated PS (PS exposure t(1/2): 242 min) and the ability to be recognized by macrophages. Purified beta2GPI bound to PS-exposing platelets (association t(1/2): 250 min). Phosphatidyl serine exposure and beta2GPI association had virtually identical kinetics. Antibody binding prolonged the exposure of the beta2GPI/PS complex (t(1/2): >1200 min). The ability to phagocytose opsonized platelets was accordingly sustained (5.3+/-0.2 opsonized platelets were internalized by each macrophage after 60 min and 9.4+/-0.3 after 300 min). Anti-beta2GPI antibodies therefore poise activated platelets in a PS-exposing status, preventing the recycling of their function and favoring their phagocytic clearance.

Antibodies↗
PubMed2000

HLA class II alleles associations of anticardiolipin and anti-beta2GPI antibodies in a large series of European patients with systemic lupus erythematosus.

The objective of this study was to determine the HLA class II associations of the anticardiolipin (aCL) and anti-beta2GPI (abeta2GPI) antibodies in a large series of European patients with systemic lupus erythematosus (SLE). A cohort of 577 European SLE patients was enrolled. aCL and abeta2GPI were measured by ELISA methods. Molecular typing of HLA-DRB1, DRB3, DRB4, DRB5, DQA1 and DQB1 loci was performed by the polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP) method. aCL of IgG, IgM and IgA isotypes were detected in 22.8%, 14% and 13.9% of patients, respectively. IgG and IgM abeta2GPI were detected in 20% of patients. aCL showed positive association with HLA DRB1*04, DRB1*0402, DRB1*0403, DRB1*07, DRB3*0301, DQA1*0201, DQA1*0301, DQB1*0302, and negative association with DQA1*0501, DRB3*0202. abeta2GPI showed positive association with DRB1*0402, DRB1*0403, DQB1*0302. DRB1*0402 carried the highest relative risk for the presence of both aCL (RR=8. 1) and abeta2GPI (RR=4.6). Our results confirm the already described associations of aCL with HLA DR4 and DR7, but also demonstrate that, among the alleles at the DRB1*04 locus, the *0402 was most represented both in aCL and in abeta2GPI positive patients. In addition, HLA class II associations of abeta2GPI are for the first time extensively examined in a large cohort of European SLE patients.

Adolescent↗
PubMed2000

Anti-ganglioside antibodies in a large cohort of European patients with systemic lupus erythematosus: clinical, serological, and HLA class II gene associations. European Concerted Action on the Immunogenetics of SLE.

OBJECTIVE: To assay anti-ganglioside antibodies (aGM1) in sera of a large cohort of European patients with systemic lupus erythematosus (SLE) to define the prevalence of these autoantibodies in SLE; to evaluate the association of aGM1 with clinical manifestations and other autoantibodies found in SLE; and to search for aGM1 association with HLA class II alleles. METHODS: Four hundred forty-eight patients with SLE were consecutively enrolled in 8 centers from 6 European countries. All sera were tested for antinuclear antibodies by immunofluorescence on HEp-2 cells as substrate, anti-dsDNA, aGM1, aCL, abeta2-glycoprotein I (abeta2-GPI) antibodies by ELISA, and antineutrophil cytoplasmic antibodies (ANCA) by immunofluorescence and by ELISA. Genomic typing for HLA class II loci was performed by polymerase chain reaction-sequence specific oligonucleotide probe method. Clinical assessment was done at the time of enrolment. RESULTS: We found 41.9% of patients with clinical signs of neuropsychiatric involvement; 15.5% of patients were positive for aGM1, 8% of the IgG isotype and 8.6% of the IgM isotype; aGM1-IgG were associated with neuropsychiatric manifestations (NPM) (RR = 3.7), with migraine (RR = 2.4), with OBS (RR = 7.3), and with peripheral neuropathy (RR = 8.5). aGM1-IgM were associated with NPM (RR = 4) and with depression (RR = 3.4). Furthermore, the genetic study showed that aGM1-IgG were associated with HLA-DQB1*0404 (RR = 7.2) while aGM1-IgM were associated with HLA-DQB1*0605 (RR = 33.3). No associations were found between aGM1 and anti-dsDNA, aCL, abeta2GP1, or ANCA. CONCLUSION: Our results show aGM1 can be found in patients with SLE. aGM1 may play a pathogenetic role for some NPM in this condition.

Adolescent↗
PubMed1999

Dendritic cell presentation of antigens from apoptotic cells in a proinflammatory context: role of opsonizing anti-beta2-glycoprotein I antibodies.

OBJECTIVE: To verify whether opsonization of apoptotic cells skews the outcome of apoptotic cell antigen presentation by dendritic cells (DCs). METHODS: RMA cells, which were engineered with a mutant ovalbumin (OVA) protein and were devoid of the leader secretory sequence (OVA-RMA), underwent ultraviolet irradiation to induce apoptosis. Binding of anti-beta2-glycoprotein I antibodies (anti-beta2GPI) and phagocytosis of apoptotic cells were assessed by flow cytometry and confocal microscopy. Presentation of processing antigens and major histocompatibility complex (MHC) class II-restricted or MHC class I-restricted antigens was assessed using OVA-specific T cell hybridomas. RESULTS: Anti-beta2GPI facilitated presentation of epitopes from internalized apoptotic cells to MHC class II-restricted, but not to class I-restricted, T lymphocytes. DCs challenged with supernatants of apoptotic cells did not activate OVA-specific T cells, making it unlikely that anti-beta2GPI complexed with antigen released from dying cells plays a role in antigen presentation. DCs challenged with low numbers of anti-beta2GPI-opsonized apoptotic cells secreted interleukin-1beta (IL-1beta), tumor necrosis factor alpha, and IL-10 in an autocrine/paracrine manner. CONCLUSION: Opsonization influences the outcome of the disposal of low numbers of apoptotic cells by DCs. This implies that soluble factors bound to apoptotic cells modulate their immunogenicity.

Antibodies↗
PubMed1999

Anti-endothelial cell IgG fractions from systemic lupus erythematosus patients bind to human endothelial cells and induce a pro-adhesive and a pro-inflammatory phenotype in vitro.

Affinity purified immunoglobulin G (IgG) fractions from systemic lupus erythematosus (SLE) patients positive for anti-endothelial cell antibodies (AECA) bind human umbilical vein endothelial cell (HUVEC) monolayers. In vitro incubation of serial protein concentrations of SLE AECA IgG induces a dose-dependent endothelial activation: i) increase of functional adhesion of the monocytic cell line U937; ii) upregulation of E-Selectin, ICAM-1, VCAM-1 expression evaluated by a cell solid-phase enzyme linked immunoassay; and iii) increased secretion of interleukin (IL)-6 in the culture supernatants. Control experiments carried out with HUVEC monolayers incubated with IgG fractions from normal healthy controls or from AECA negative SLE sera do not affect at all endothelial adhesion molecule expression or pro-inflammatory cytokine secretion. The AECA IgG effects are not related to both anti-phospholipid or anti-DNA activities. Taken together the findings suggest that these autoantibodies might be important in recruiting and in activating mononuclear leukocytes responsible for vessel wall infiltration and raise the possibility that AECA might display a pathogenic role in SLE vessel damage.

Adult↗
PubMed1999

Central nervous system involvement in systemic lupus erythematosus patients without overt neuropsychiatric manifestations.

OBJECTIVE: To verify whether features of CNS involvement can be detected in SLE patients without overt neuropsychiatric manifestations. METHODS: 114 SLE patients who had never received a diagnosis of neuropsychiatric lupus (never-NPSLE) were studied and compared to 65 SLE patients with known neuropsychiatric involvement (NPSLE). The study relied on evaluation of neurocognitive functions by means of a battery of neuropsychological tests, on psychiatric and neuropsychological assessments and on neuroimaging studies (computed tomography, magnetic resonance, single photon emission computed tomography (SPECT)). RESULTS: Clinical features, including disease duration/activity and pharmacological therapy, of never-NPSLE and NPSLE patients were similar. Short-term and long-term memory, visuo-spatial and verbal information processing were similarly compromised in never-NPSLE and in NPSLE patients; only attention was significantly more compromised in NPSLE patients. Psychiatric morbidity was higher than expected in never-NPSLE patients, although less than in the control neuropsychiatric group. Ischemic lesions, multiple small high intensity lesions and cortical atrophy, detected by CT and MR scans, as well as abnormal SPECT were also frequently detected in never-NPSLE patients. Interestingly, left parietal and occipital area hypoperfusion by SPECT was significantly more frequent in the patients with impaired visuo-spatial intelligence and short-term memory. CONCLUSIONS: Most abnormalities detected by available diagnostic tools and characteristics of neuropsychiatric SLE are also present in non-symptomatic patients. They may derive from an unexpected widespread involvement of the CNS and are not per se sufficient, in the absence of clinical manifestations, for a diagnosis of neuropsychiatric SLE.

Adult↗
PubMed1999

Anticardiolipin and anti-beta2GPI antibodies in a large series of European patients with systemic lupus erythematosus. Prevalence and clinical associations. European Concerted Action on the Immunogenetics of SLE.

OBJECTIVE: To test the prevalences and the clinical associations of anticardiolipin (aCL) and anti-beta2GPI (abeta2GPI) antibodies in a large series of European patients with systemic lupus erythematosus (SLE). METHODS: 574 SLE patients from 7 European countries were tested for aCL and abeta2GPI by ELISA methods. RESULTS: aCL of IgG, IgM, and IgA isotypes were detected in 22.8%, 14%, and 13.9% of the patients, respectively. IgG and IgM abeta2GPI were detected in 20% of the patients. The presence of aCL was highly associated with the presence of abeta2GPI. Medium-high titer IgG aCL and abeta2GPI were associated with thrombosis, with similar sensitivity, specificity, and positive predictive value. When present at medium-high titer, IgG aCL were associated with thrombocytopenia, IgM aCL with hemolytic anemia, and cerebrovascular accidents. IgA aCL with livedo reticularis and Raynaud's phenomenon. CONCLUSIONS: aCL, when present at medium-high titer, are as important as abeta2GPI, as a risk factor for thrombosis. Medium-high titer aCL, but not abeta2GPI, are associated with other clinical features of the antiphospholipid syndrome.

Adolescent↗
PubMed1998

Oral tolerance to low dose beta 2-glycoprotein I: immunomodulation of experimental antiphospholipid syndrome.

Oral tolerance was induced in BALB/c mice by feeding low dose beta2-glycoprotein I (beta2GPI). The beta2GPI-fed mice did not develop serologic and clinical markers of experimental antiphospholipid syndrome (APS) upon immunization with the autoantigen. The treated group was characterized by low titers of serum anti-beta2GPI and anticardiolipin Abs in the serum, lack of fetal resorptions, low incidence of thrombocytopenia, and normal aPTT (activated partial thromboplastin time) values. Beta2GPI given orally before priming with beta2GPI resulted in complete prevention of experimental APS development; beta2GPI given at an early stage of the disease reduced clinical manifestations. However, administration of beta2GPI 70 days postimmunization had a less significant effect on disease expression. Tolerized mice exhibited a diminished T lymphocyte proliferation response to beta2GPI in comparison with beta2GPI-immunized mice fed with OVA. When nontolerant beta2GPI-primed T lymphocytes were mixed with T lymphocytes derived from tolerized mice, a significant inhibition of proliferation upon exposure to beta2GPI was observed. The induction of suppression was beta2GPI specific and driven, as well as TGF-beta mediated. The beta2GPI-specific response of T lymphocytes from the beta2GPI-fed mice was reversed by anti-TGF-beta Abs. The tolerance was adoptively transferred by CD8+ T cells from the tolerized mice into naive mice. Those CD8+ cells were MHC class I restricted, found to secrete TGF-beta, and had no cytolytic activity. Oral administration of beta2GPI suppressed priming of CTLs in the recipient mice. In sum, beta2GPI-induced oral tolerance has an immunomodulatory effect in experimental APS, demonstrating the importance of beta2GPI in the pathogenesis of the disease.

Administration, Oral↗
PubMed1998

Human beta 2-glycoprotein I binds to endothelial cells through a cluster of lysine residues that are critical for anionic phospholipid binding and offers epitopes for anti-beta 2-glycoprotein I antibodies.

Beta 2-Glycoprotein I (beta 2GPI) is a phospholipid-binding protein recognized by serum autoantibodies from the anti-phospholipid syndrome both in cardiolipin- and beta 2GPI-coated plates. We found that: 1) recombinant wild-type beta 2GPI bound to HUVEC and was recognized by both human monoclonal IgM and affinity-purified polyclonal IgG anti-beta 2GPI anti-phospholipid syndrome Abs; and 2) a single amino acid change from Lys286 to Glu significantly reduced endothelial adhesion. Double and triple mutants (from Lys284,287 to Glu284,287, from Lys286,287 to Glu286,287, and from Lys284,286,287 to Glu284,286,287) completely abolished endothelial binding. A synthetic peptide (P1) spanning the sequence Glu274-Cys288 of the beta 2GPI fifth domain still displayed endothelial adhesion. Another peptide (P8), identical with P1 except that Cys281 and Cys288 were substituted with serine residues, did not bind to HUVEC. Anti-beta 2GPI Abs, once bound to P1 adhered to HUVEC, induced E-selectin expression and up-regulated IL-6 secretion. Control experiments conducted with irrelevant Abs as well as with the P8 peptide did not show any endothelial Ab binding nor E-selectin and IL-6 modulation. Our results suggest that: 1) beta 2GPI binds to endothelial cells through its fifth domain; 2) the major phospholipid-binding site that mediates the binding to anionic phospholipids is also involved in endothelial binding; 3) HUVEC provide a suitable surface for beta 2GPI binding comparable to that displayed by anionic phospholipids dried on microtiter wells; and 4) the formation of the complex between beta 2GPI and the specific Abs leads to endothelial activation in vitro.

Amino Acid Sequence↗