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Biomedical subjects

Y Shoenfeld

Publications and source records attributed to Y Shoenfeld.

At least 199 records · Page 11Linked to original sources
PubMed2000

Mycoplasma-pneumoniae-induced thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is a fatal disease characterized by widespread platelet aggregation, hemolytic anemia and fever with renal and neurological involvement. Different factors have been associated with the development of TTP, e.g. infections, pregnancy, chemotherapy, drug therapy and bone marrow transplantation. Recent data imply that all these different causes may induce the disease by decreasing the activity of the plasma von Willebrand factor-cleaving protease resulting in unusually large von Willebrand factor multimers that later on initiate the cascade of TTP. In this communication, we present a unique association between infection with Mycoplasma pneumoniae and TTP. We believe that the emergence of antibodies that cross-react with Mycoplasma and the protease might elucidate in this case the pathogenesis of TTP.

Adult↗
PubMed2000

Dermatomyositis and polymyositis associated with the antiphospholipid syndrome-a novel overlap syndrome.

OBJECTIVE: As APS (antiphospholipid syndrome) can be either primary or secondary to a wide range of other conditions (such as autoimmune diseases, malignancies, infectious diseases, and drug-induced conditions) the aim of this study was to describe a novel overlap syndrome of APS. METHODS: All patients diagnosed with either PM (polymytosis) or DM (dermatomytosis) who were treated in the Rheumatology Unit, Sheba Medical Center, were followed-up in the past 8 years for the appearance of a clinical manifestation of the APS, and conversely, patients with APS treated by us were clinically assessed for the presence of signs and symptoms of PM and DM. Both conditions were diagnosed according to accepted diagnostic criteria. RESULTS: Three patients were found to have both APS and PM/DM. A patient with PM had transverse myelopathy, a patient with DM had pulmonary embolism, and a patient with PM had recurrent abortions, stroke, livedo reticularis and mitral regurgitation. Both patients with PM had also SLE (systemic lupus erythematosis). CONCLUSIONS: APS can be associated with a wide range of diseases. Future data would reveal which therapy is the best for the association of PM/DM with APS, and determine the pathogenesis and prognosis in patients with this association.

Adult↗
PubMed2000

Autoimmunity in atherosclerosis: lessons from experimental models.

The modern view of atherosclerosis is of a chronic inflammatory disorder. In accord with this paradigm, the process of uninhibited influx of fat to the vessel wall results from an 'adequate' response to various forms of injury (i.e. turbulence, infections, modified lipoproteins). This idea has been further extended by several groups, to assume that the atherosclerotic lesion can be the target of an autoimmune mediated attack. According to this hypothesis, the site of initiation of the plaque should bear/express the target autoantigen, whereas concomitantly a respective immune response is generated in the periphery. The examples illuminating this notion are beta2GPI as a target autoantigen, HSP60/65 an oxidized-LDL. Herein we present evidence to support the involvement of autoimmune mechanisms in atherogenesis based on the experience from experimental models and human studies.

Animals↗
PubMed2000

Central nervous system involvement in systemic lupus erythematosus: cerebral imaging and serological profile in patients with and without overt neuropsychiatric manifestations.

The aim of this study was to evaluate morphological and functional abnormalities by cerebral imaging in a series of systemic lupus erythematosus (SLE) patients with and without overt central nervous system (CNS) manifestations, and to detect possible relationships with clinical parameters and a large panel of autoantibodies, including those reactive against neurotypic and gliotypic antigens. 68 patients with SLE were investigated in a cross-sectional study which included clinical evaluation of symptoms, cerebral magnetic resonance imaging (MRI) and brain single photon emission tomography (SPECT) analysis, electroencephalography (EEG), and serological tests for antibodies directed against nuclear, cytoplasmic neuronal and glial cell-related antigens. The results of this study showed: (1) a significant positive association of (a) anti-glial fibrillary acidic protein (GFAP) serum antibodies with neuropsychiatric (NP) manifestations and (b) anti-serin proteinase 3 (anti-PR3/c-ANCA) serum antibodies with pathological cerebral SPECT; (2) the presence of significantly higher values of (a) SLICC organ damage index in patients with abnormal MRI and (b) SLAM activity index in patients with abnormal SPECT; and (3) the association of (a) abnormal MRI with nonactive NP manifestations and (b) combined abnormality of brain SPECT and MRI with the occurrence of overall overt NP manifestations and with those of the organic/major type. Neuropsychiatric manifestations, namely those of the organic/major type, appeared to be significantly associated to the presence of a serum antibody against GFAP, a gliotypic antigen. There was also evidence of an association between SPECT abnormality and the presence of anti-PR3 (c-ANCA). Furthermore, brain imaging by MRI and SPECT applied to SLE patients appears to express CNS involvement significantly related to specific categories of NP manifestations. The abnormalities detected by the two tests seem to be preferentially associated with different activity phases of the NP disorder or of the lupus disease.

Adolescent↗
PubMed2000

Peptide immunotherapy in autoimmune diseases.

Peptide-mediated immunotherapy has been studied in a number of experimental models of autoimmune diseases and has also been tested in human patients to a certain extent. Copolymer 1 is a synthetic amino acid copolymer that has been demonstrated to suppress experimental autoimmune encephalomyelitis (a model for multiple sclerosis) when administered parenterally. Some study results indicate that mucosal tolerance induced by appropriate recombinant peptide fragments of human AChR is effective in suppressing experimental autoimmune myasthenia gravis and might be considered as a therapeutic modality for patients with MG. A peptide of the heat-shock protein 60 molecule, designated peptide p277, was shown to be a target of T cells in autoimmune diabetes in NOD mice, and intraperitoneal injections of glutamic acid decarboxylase (GAD) peptide 524-543 delayed the onset of diabetes and significantly reduced its incidence. Experimental evidence has revealed that CDR-based peptides may be potential candidates for the therapy of systemic lupus erythematosus. The use of synthetic peptides that focus on neutralization of pathogenic anti-beta 2GPI antibodies represents a possible new therapeutic approach to antiphospholipid syndrome. Studies in both acute and chronic-relapsing experimental autoimmune uveoretinitis have indicated that oral administration of S-Ag, S-Ag-derived peptides, inter-photoreceptor retinoid binding protein or HLA-derived peptides before immunization can protect animals from the disease.

Journal Article↗
PubMed2000

Detection of antibodies to gangliosides and glycolipids in various intravenous immunoglobulin (IVIg) preparations.

The aim of this study was to examine the presence of antibodies to GM1 and sulfatide in various IVIg preparations. Five brands of commercially available human IVIg (Sandoglobulin, Isiven, Cytogam, Omrigam and Cutter) were examined and compared. Serial dilutions of each of the above preparations were prepared at a working range of 0.009 to 25.0 mg/ml IVIg, and screened by a standard 96-well microplate EIA for autoantibodies to the ganglioside GM1 and to the glycolipid sulfatide. The various IVIg preparations (Omrigam, Cytogam, Sandoglobulin, Isiven), except for Cutter IVIg, contained low to medium titers of the autoantibodies tested. Omrigam and Cytogam IVIg contained low titer of antibodies to GM1, and medium-titer of antibodies to sulfatide, whereas Sandoglobulin and Isiven contained only low-titer of autoantibodies to sulfatide. The presence of natural autoantibodies to myelin in human sera may explain the presence of the tested antibodies within IVIg preparations. Measurements of antibodies to ganglioside and glycolipid in sera of Guillain-Barré patients immediately following IVIg, would probably not reveal antibody decrease. Alternatively, long-term (several weeks) follow-up of titers might result in their modification due to inhibition of antibodies production by IVIg.

Autoantibodies↗
PubMed2000

Immunomodulation of experimental autoimmune diseases via oral tolerance.

The concept of oral tolerance refers to a form of peripheral tolerance in which mature lymphocytes in the peripheral lymphoid tissues are rendered nonfunctional or hyporesponsive by prior oral administration of an antigen. The primary mechanisms mediating oral tolerance include deletion, anergy of antigen-specific T cells and active cellular suppression, the primary determining factor being the dose of fed antigen. Low doses favor active suppression, whereas high doses favor deletion and anergy. Active cellular suppression is mediated by the induction of regulatory T cells in the gut-associated lymphoid tissue, which migrate to the systemic immune system. One of the primary mechanisms of active cellular suppression is via secretion of suppressive cytokines such as TGF-beta, IL-4, and IL-10 following antigen-specific triggering. TGF-beta is produced both by CD4+ and CD8+ GALT-derived T cells and is an important mediator of the active suppression component of oral tolerance. CD4+ cells that primarily produce TGF-beta appear to be a unique T-cell subset and termed Th3 cells. Oral tolerance was successfully studied in a variety of experimental models for autoimmune diseases, among them experimental autoimmune encephalomyelitis, experimental arthritis, experimental anti-phospholipid syndrome, experimental autoimmune uveoretinitis, experimental insulin dependent diabetes mellitus (IDDM), and experimental autoimmune myasthenia gravis. The results obtained in experimental animal models have led to the conduction of several clinical trials of oral tolerance in patients with multiple sclerosis, rheumatoid arthritis, uveitis, and IDDM. Conflicting results were obtained, and although some improvement has been noted in some of the patients, broad ranging clinical improvement has not yet been observed. A more accurate choice of antigens, as well as more precise dosing and timing of antigen-administration might lead to better results in the future.

Animals↗
PubMed2000

How to outfox mother nature--autoimmunity: moving from shadows to sunshine.

The morbidity and disability associated with autoimmune diseases represent a significant health problem. One in 31 people have one form or another of an autoimmune disease. Despite the avalanche of molecular data, immunogenetic definitions and improvements in serologic diagnosis, we are still far from discovering the etiologies of these diseases. For some autoimmune diseases, there may be a very long latency period between disease onset and clinical presentation. Existing therapies tend to be only partially successful and often accompanied by a variety of serious side effects. However, even in the absence of a complete understanding of the underlying genetic, environmental and coincidental factors that confer susceptibility to autoimmune diseases, we believe that it is possible to devise successful therapies by interfering with one or more of the pathways of destruction characteristic of a specific autoimmune disease. We have prepared a futuristic look at the treatment of autoimmune disease by extrapolation of current research directions as well as thoughts on new methods of delivery of recombinant monoclonal antibodies. We predict that we will "cure" autoimmune pathology long before we understand the etiology. In the case of inflammatory bowel disease, as a model, and taking advantage of what is known on animal studies, we illustrate the progress that has been made in elucidating these pathways of destruction and speculate about possible therapeutic approaches.

Animals↗
PubMed2000

Anti-beta 2-glycoprotein I antibodies and anti-endothelial cell antibodies induce tissue factor in endothelial cells.

Anti-beta 2-glycoprotein I antibodies bind to endothelial cells through beta 2-GPI. The antibodies are present in patients with systemic lupus erythematosus and antiphospholipid syndrome and are associated with the pathogenesis of the disease. Anti-endothelial cell antibodies that react with constitutive antigens on ECs are present in patients with vasculiditis and other diseases. Both types of antibodies can activate ECs. Frequent findings in APLS and vasculitis are fibrin deposits and thromboembolic phenomena. These indicate that the coagulation system is activated. However, the mechanism of activation is not clear. ECs generate tissue factor upon stimulation with various substances. In the present study we report that monoclonal anti-beta 2-GPI antibodies and AECAs, derived from a patient with primary APLS and a patient with Takayasu's arteritis, respectively, induce a potent tissue factor in ECs. The production of TF activity, TF antigen and TF mRNA is dose and time dependent. The TF activity was induced also by F(ab)2 but not by Fc fragments and was abolished completely by pre-incubation with ant-TF antibodies. The TF that is induced in ECs by AECAs with and without beta 2-GPI specificity may activate the coagulation and thereby play a major role in the pathogenesis of fibrin deposition and thrombus formation in diseases that are associated with the presence of these antibodies.

Antibodies↗