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Biomedical subjects

P L Meroni

Publications and source records attributed to P L Meroni.

At least 109 records · Page 6Linked to original sources
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

Post-partum dilated cardiomyopathy in anti-phospholipid positive woman.

Recurrent fetal loss and pregnancy complications, especially severe early-onset preeclampsia, are frequently associated with anti-phospholipid antibodies. We report a case of post-partum cardiac involvement leading to dilated cardiomyopathy in a woman with a persistent positivity for anti-cardiolipin and anti-nuclear antibodies. Her clinical and obstetric record reported two previous fetal losses but no other signs characteristic of the anti-phospholipid syndrome or diagnostic for a systemic lupus erythematosus. Post-partum cardiomyopathy might be another cardiac presentation of the anti-phospholipid syndrome, in addition to the well known valvular involvement. In patients with persistent positivities for anti-phospholipid antibodies, a prompt identification of such a complication in the post-partum period should be taken into account by physicians. Adequate cardiologic treatment associated with antiaggregant and steroid therapy might be useful to prevent further complications in these patients.

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↗
PubMed1996

Fusidic acid and insulin-dependent diabetes mellitus.

Insulin-dependent diabetes mellitus (IDDM) is a major cause of morbidity and mortality from long-standing complications. The autoimmune nature of IDDM has encouraged use of immunosuppressive and antiinflammatory strategies to better preserve residual pancreatic beta-cell function at the time of diagnosis. Fusidic acid and its sodium salt, fusidin, is a relatively atoxic antibiotic used mainly in the treatment of staphylococcal infections. Recently, fusidin has been demonstrated to possess immunosuppressive functions in vitro and in vivo, and the drug has shown promise in preventing the disease in animal models of IDDM and in a preliminary trial in IDDM patients.

Animals↗
PubMed1995

Characterization of biologically active antineutrophil cytoplasmic antibodies induced in mice. Pathogenetic role in experimental vasculitis.

OBJECTIVE: To investigate the pathogenetic role of antineutrophil cytoplasmic antibodies (ANCA) in Wegener's granulomatosis (WG). METHODS: BALB/c mice were immunized with human IgG ANCA from a patient with WG. Control mice were immunized with normal human IgG. Levels of mouse ANCA and other autoantibodies were determined. Mouse ANCA were tested for their ability to induce adhesion and respiratory burst of neutrophils. The mouse lungs and kidneys were examined for the development of vasculitis. RESULTS: Mice immunized with human ANCA developed anti-human ANCA and anti-anti-human ANCA (mouse ANCA), while the controls did not develop these antibodies. Mouse ANCA were capable of inducing adhesion of neutrophils to fibronectin and activating the respiratory burst in neutrophils. Moreover, the mice that were immunized with human ANCA developed perivascular mononuclear cell infiltrates in the lungs, suggesting vasculitis. CONCLUSION: The results suggest a pathogenic role of ANCA in WG, and may imply that activation of neutrophils is the initiating event in the development of vasculitis in WG.

Animals↗
PubMed1995

In vitro production of type 1 and type 2 cytokines by peripheral blood mononuclear cells from high-risk HIV-negative intravenous drug users.

OBJECTIVE: To study type 1 and type 2 cytokine patterns in HIV-negative high-risk intravenous drug users (IVDU). DESIGN: We investigated interleukin (IL)-2, interferon (IFN)-gamma, IL-4, IL-6 and IL-10 production by phytohaemagglutinin (PHA)-stimulated and unstimulated peripheral blood mononuclear cell (PBMC) cultures from HIV-negative high-risk IVDU, HIV-negative controls and HIV-positive subjects. METHODS: Cytokine production was measured in supernatants using enzyme-linked immunosorbent assay (ELISA) in 10 HIV-negative high-risk IVDU, 25 HIV-negative controls, and 12 HIV-positive IVDU. We also determined spontaneous in vitro immunoglobulin (Ig) G and IgM production. RESULTS: HIV-negative high-risk IVDU showed increased IFN-gamma and decreased IL-4, IL-10 and IL-2, although the latter was not significant compared with HIV-negative controls. Further, HIV-negative high-risk IVDU had reduced IgG production and impaired IgM-IgG switch. CONCLUSIONS: The reduced IL-2 and IL-4 production suggest an impaired CD4+ T-cell function in HIV-negative high-risk IVDU. The increased IFN-gamma production along with the decreased type 2 cytokine profile is consistent with the hypothesis that protective immunity against HIV may reside in type 1 responses and cell-mediated immunity.

Adolescent↗
PubMed1995

Immunization with anti-neutrophil cytoplasmic antibody (ANCA) induces the production of mouse ANCA and perivascular lymphocyte infiltration.

Wegener's granulomatosis (WG) is a granulomatous necrotizing vasculitis associated with the presence of ANCA, predominantly directed against proteinase 3 (PR3). The titres of ANCA correlate with disease activity and titre increases may precede disease exacerbations. Previously, we have shown that it is possible to induce autoimmune disease (systemic lupus erythematosus (SLE) and anti-phospholipid syndrome) in naive mice following active immunization with human autoantibodies, namely anti-DNA and anti-cardiolipin, respectively. The mice developed first anti-autoantibodies and, after about 4 months anti-anti-autoantibodies (Ab3), simulating auto-antibodies (Ab1) in their binding activities, and their presence was associated with the development of disease manifestations, characteristic of the human disease. So far, there is no good animal model for WG. In the current study we have immunized mice with human ANCA with the aim of inducing experimental WG. In two separate studies 30 mice were immunized in their footpads with autoantigen-purified IgG fraction (ANCA) from the sera of two patients with untreated WG, emulsified in Freund's complete adjuvant, followed 3 weeks later by ANCA injection in PBS. In the first experiment mice immunized with ANCA developed sterile microabscesses in the lungs after 8 months, and died after 8-15 months. In the second experiment, mice immunized with ANCA developed after 4 months mouse ANCA, with specificity both to PR3 and to myeloperoxidase, as well as anti-endothelial autoantibodies (AECA), as shown by radioimmunoprecipitation. Pathologically, the immunized mice developed proteinuria but not haematuria, and histological sections of the lungs demonstrated mononuclear perivascular infiltration, while diffuse granular deposition of immunoglobulins was noted in the kidneys. Our results point to a pathogenic role of ANCA in WG, and confirm the importance of the idiotypic network in the etiopathogenesis of autoimmune conditions.

Animals↗
PubMed1995

Placental thrombosis and fetal loss after passive transfer of mouse lupus monoclonal or human polyclonal anti-cardiolipin antibodies in pregnant naive BALB/c mice.

In the present study we evaluated the effect of passive transfer of a mouse monoclonal (CAM) or a human polyclonal anti-cardiolipin IgG on pregnancy outcome in BALB/c mice. The mice were immunized through the tail vein immediately after mating with 10 micrograms of monoclonal or polyclonal anti-cardiolipin antibodies. Two other groups of mice were given a mouse irrelevant monoclonal antibody or normal human polyclonal IgG respectively, at the same dose. In mice immunized with monoclonal or polyclonal anti-cardiolipin antibody we observed a significant increase in the number of fetal resorptions and a significant reduction of the mean weights of the embryos and the placentas. In mice immunized with CAM we also found a significant decrease in the number of healthy pups, while mice infused with human aCL antibody expressed a significant reduction in the fecundity rate. The histological examination showed widespread thrombosis and necrosis in the placentas derived from the mice immunized with the anti-cardiolipin antibodies. The model supports a possible direct pathogenetic effect of anti-phospholipid antibodies in recurrent fetal loss and points out that thrombotic events at placental level can be instrumental in the pathogenesis of the obstetric complications.

Animals↗
PubMed1995

Autoantibody profile of primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a chronic progressive liver disease of unknown etiology. It has been suggested that genetic and immunological factors are important in its pathogenesis. The present study examined the prevalence of 23 different autoantibodies in 25 PSC sera, by ELISA, in order to better define the autoimmune profile of PSC. The results indicate that 88% of PSC patients produced at least 1 autoantibody, and 36% had reactivity to multiple autoantibodies. Moreover, 35% of the PSC patients produced anti-endothelial-cell antibodies (AECA) and 75% of the sera contained perinuclear antineutrophil cytoplasmic antibodies (pANCA), detected by indirect immunofluorescence. The prominent ANCA autoantibody was anti-cathepsin-G, demonstrated in 35% of the patients. The multiplicity of the autoantibody profile, revealed in the present study, points to the autoimmune characteristics of PSC. In addition, the association of ANCA and of AECA in PSC may suggest a pathogenic role for these antibodies in PSC.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1995

Autoimmunity and thyroid function in patients with chronic active hepatitis treated with recombinant interferon alpha-2a.

The occurrence of thyroid abnormalities and the appearance of organ- and non-organ-specific autoantibodies during long-term recombinant interferon alpha-2a (IFN-alpha) therapy were studied in 86 and 51 consecutive outpatients with hepatitis C and B virus-related chronic active hepatitis (CAH-HCV and CAH-HBV), respectively. Most patients had longstanding community-acquired hepatitis. At baseline, 9.3% of CAH-HCV and 3.9% of CAH-HBV patients showed clinical and/or biochemical signs of thyroid dysfunction. The remaining patients were euthyroid, although anti-thyroid autoantibodies were found in 33/78 (42.3%) of CAH-HCV and in 5/49 (10.2%) of CAH-HBV patients. During IFN-alpha treatment, increased anti-thyroid autoantibody levels were seen in 40% of CAH-HCV initially negative patients, while they became detectable in no more than 10% of CAH-HBV patients. Interferon-alpha-induced hypo- or hyperthyroidism was recorded in 12 of 35 CAH-HCV patients treated for 12 months (34.3%). Only one CAH-HBV patient developed hyperthyroidism. High titers of anti-nuclear autoantibodies (ANA) were recorded at enrollment in 5/36 (13.8%) of CAH-HCV and in 3/16 (18.7%) of CAH-HBV patients. Only one CAH-HCV patient displayed anti-parietal cell antibodies (PCA). After IFN-alpha treatment, ANA were found in 10/28 (35.7%) and PCA in 2/28 (7.1%) of CAH-HCV patients, while an additional CAH-HBV patient developed PCA, but not ANA. However, no signs of systemic autoimmune disease were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effects of sodium fusidate in animal models of insulin-dependent diabetes mellitus and septic shock.

We have evaluated the effects of the novel immunosuppressant sodium fusidate (fusidin) in the non-obese diabetic (NOD) mouse and in D-galactosamine (D-Gal)-presensitized BALB/c mice challenged with the bacterial superantigen, Staphylococcus aureus enterotoxin B (SEB) or with the endotoxin, Escherichia coli lipopolysaccharide (LPS). The NOD mouse model has clinical and histoimmunological features similar to those of human insulin-dependent diabetes mellitus (IDDM). The SEB- and LPS-treated BALB/c mouse models exhibit pathogenic similarities with human septic shock conditions. In the NOD mouse, fusidin suppressed the spontaneous development of insulitis (mean inhibition 73%) and hyperglycaemia (IDDM incidence 25% versus 0%) when administered at 40 mg/kg five times weekly for 8 consecutive weeks from the fourth week of age; concurrently treated animals exhibited reduced percentages of splenic T lymphocytes. This anti-diabetogenic effect was confirmed in the accelerated model of diabetes induced in the NOD mouse with cyclophosphamide (CY) (IDDM incidence 55% versus 21-6% using dosages of fusidin from 40 to 80 mg/kg five times weekly); protection from IDDM development was achieved even when the drug (80 mg/kg/day) was first administered 7 days after CY challenge. In contrast, fusidin did not reverse hyperglycaemia when administered to CY-treated animals within 3 days of IDDM development. In the two models of septic shock, prophylactic treatment with fusidin, 80 mg/kg given three times for 2 days prior to D-Gal/SEB or D-Gal/LPS challenge, drastically reduced the lethality compared with D-Gal/buffer-treated mice. This effect may depend on the inhibitory action of fusidin on the secretion of cytokines such as interferon-gamma and tumour necrosis factor-alpha, the serum levels of which were greatly diminished in the fusidin-treated mice (mean inhibition 50-90%). These results demonstrate that fusidin may have a role in the treatment of cell-mediated autoimmune diseases and cytokine-mediated infectious diseases in humans.

Animals↗
PubMed1995

Aspirin modulates interleukin-3 production: additional explanation for the preventive effects of aspirin in antiphospholipid antibody syndrome.

OBJECTIVE: The granulocyte macrophage colony stimulating factors (GMCSF) and interleukin-3 (IL-3) are defined as positive signals for pregnancy, since they support the process of trophoblast invasion and expansion and induce placental growth and development. Aspirin and IL-3 were shown to be effective in preventing the manifestations of experimental antiphospholipid antibody syndrome (APS). Aspirin inhibits the activity of the enzyme cyclooxygenase in macrophages, which leads to a shift in the arachidonic acid metabolism toward the lipoxygenase pathway, and results in overproduction of leukotrienes. Our data indicated that leukotrienes are capable of stimulating IL-3 production in vitro. Our aim was to examine whether aspirin may exert its beneficial effect in APS not only by its ability to prevent thromboxane A2 production and prostaglandin I2 (PGI2) formation, but also by stimulating IL-3 production. METHODS: Splenocytes and macrophages from naive mice were cultured in vitro with low dose aspirin. Nordihydroguaiaretic acid (NDGA), an inhibitor of 5-lipoxygenase, was added to mixed cultures of splenocytes and macrophages containing low dose aspirin. IL-3 production was observed. RESULTS: When splenocytes and macrophages were cultured in vitro with low dose aspirin (10 micrograms/ml), a marked stimulation of IL-3 production was noted. When NDGA was added to mixed cultures of splenocytes and macrophages containing low dose aspirin, it decreased the IL-3 production. Higher dose of aspirin did not affect the cytokine production. When splenocytes were incubated without the addition of exogenous macrophages, no stimulation of IL-3 production was noted. However, when purified leukotriene B4 or leukotriene C4 was added, there was an increase of 71 and 261%, respectively, in the stimulation of IL-3 production (p < 0/01). These results were supported by in vivo studies, in which a higher serum IL-3 level was detected in mice fed low dose aspirin, compared to the control group and to mice fed a higher dose of aspirin. CONCLUSION: Aspirin acts as a potent stimulator of IL-3 through its ability to raise leukotriene production, which induces production of IL-3 both in vitro and in vivo.

Animals↗
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-endorphin content in HIV-infected HuT78 cell line and in peripheral lymphocytes from HIV-positive subjects.

We investigated beta-endorphin (BE) content in an HIV-infected cell line and in peripheral blood mononuclear cells (PBM) from HIV-positive subjects. HIV infection increased BE content in HuT78 cell line compared to uninfected cells. Accordingly, BE content was greater in HIV-positive subjects than in healthy controls, both in fresh PBM and in mitogen-stimulated or unstimulated cultured cells. Further, in PHA-stimulated cultures, BE increase was correlated with disease progression. Opioids are known to decrease immune responsiveness in vivo, and it may be that the increased BE concentrations contribute to HIV-associated immune deficiency. In HIV-positive subjects, but not in healthy controls, intracellular BE concentration was positively correlated with PHA-induced PBM proliferation. The latter data suggest an alternative explanation: that the increased BE content represents a paradoxical response of the host in an attempt to balance virus-induced immunodepression. Thus, BE may be important in fine-tuning of the immune response with its up- and downregulation dependent upon differences in immune status.

Adult↗