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Spontaneous autoimmunity in 129 and C57BL/6 mice-implications for autoimmunity described in gene-targeted mice.

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder in which complex genetic factors play an important role. Several strains of gene-targeted mice have been reported to develop SLE, implicating the null genes in the causation of disease. However, hybrid strains between 129 and C57BL/6 mice, widely used in the generation of gene-targeted mice, develop spontaneous autoimmunity. Furthermore, the genetic background markedly influences the autoimmune phenotype of SLE in gene-targeted mice. This suggests an important role in the expression of autoimmunity of as-yet-uncharacterised background genes originating from these parental mouse strains. Using genome-wide linkage analysis, we identified several susceptibility loci, derived from 129 and C57BL/6 mice, mapped in the lupus-prone hybrid (129 x C57BL/6) model. By creating a C57BL/6 congenic strain carrying a 129-derived Chromosome 1 segment, we found that this 129 interval was sufficient to mediate the loss of tolerance to nuclear antigens, which had previously been attributed to a disrupted gene. These results demonstrate important epistatic modifiers of autoimmunity in 129 and C57BL/6 mouse strains, widely used in gene targeting. These background gene influences may account for some, or even all, of the autoimmune traits described in some gene-targeted models of SLE.

Animals↗

Autoantibodies to insulin do appear in non-diabetic patients with autoimmune disorders: comparison with anti-immunoglobulin antibodies and other autoimmune phenomena.

Insulin- and anti-immunoglobulin-antibodies have been recently reported in pre-diabetic subjects: the former has been proposed as a predictive marker of Type I diabetes in non-diabetic-subjects. To evaluate the diabetes-related specificity of these antibodies, the presence of insulin autoantibodies, using a recently developed and highly sensitive competitive radioimmune assay, and of anti-immunoglobulin antibodies together with that of immune complexes and of other autoantibodies has been investigated in patients with organ- or non-organ-specific autoimmune diseases. One hundred and eleven serum samples were assayed from patients with Graves' disease, primary hypothyroidism, chronic autoimmune thyroiditis, Addison's disease, chronic autoimmune hepatitis, pernicious anemia, lupus erythematosus, and rheumatoid arthritis, together with 45 serum samples from normal subjects. From patients with autoimmune diseases, 32.4% of all sera revealed values of insulin autoantibodies above the limit of positivity (p less than 0.001); anti-immunoglobulin antibodies were present in 4.1% of patients (NS); immune complexes were found in 19.5% (NS) of all patients, but in 38% of patients with Graves' disease and chronic hepatitis (p less than 0.02). There was a trend for multiple autoantibody positivity to be associated with high levels of insulin autoantibodies (p less than 0.05). Thus, whereas contrary to expectation anti-immunoglobulin antibodies are not associated with non-diabetes-related autoimmune diseases, increased humoral immunoresponsiveness to endogenous insulin appears to be related to autoimmunity in general rather than restricted to Type I diabetes.

Adult↗

[Autoimmune mechanisms in endocrinology--the polyglandular autoimmune endocrine syndrome].

Autoimmune endocrinopathies belong to so-called organ specific autoimmune diseases. These diseases combine very often and from the polyglandular autoimmune endocrine syndrome (PAES), where autoantibodies either destroy or stimulate individual endocrine glands or hormone receptors in target tissues. Thus a wide range of combinations of hypofunctional or hyperfunctional clinical syndromes develops. PAES is a good natural model of endocrine polyautoaggressiveness. In its development the following aetiopathogenetic factors participate: 1. Hereditary familial disposition, expressed e.g. by certain inherited HHS genes (e.g. A1, B8, DR 3, 4). 2. Aberrant expression of these DR genes on endocrine organs due to bacterial or viral infections, pregnancy, stimulation of the thyroid gland by TSH or immunoglobulins (TSIg). 3. Antigenic mimicri and the presentation of autoantigens to immunocompetent cells. 4. Impaired immunoregulation--antigen specific insufficiency of suppressor T lymphocytes. 5. Local and general amplification reaction to an autoimmune process. 6. The development and autoreproduction of organ specific autoimmune endocrine disease and its development into the final stage of endocrine disease where autoantibodies may disappear. The diagnosis of PAES in clinical practice is difficult. Common immunological tests are not very conclusive. To assess a polyglandular affection we found useful the multiaxial synchronous test where stimulation of several hypothalamic releasing hormones combined with a hypoglycaemic stimulus is used. Autoimmune lymphocytic hypophysitis is part of PAES. In clinical practice this syndrome is therefore frequently incorrectly diagnosed and then incorrectly treated.

Autoimmune Diseases↗

D-penicillamine-induced autoimmunity in Brown-Norway rats. Similarities with HgCl2-induced autoimmunity.

D-penicillamine (DP) has been previously shown to induce an autoimmune disease in Brown-Norway (BN) rats, characterized by a dermatitis, by the production of antinuclear antibodies, by the formation fo circulating immune complexes, and by linear IgG deposits along the glomerular basement membrane. These manifestations are quite similar to those observed in mercuric chloride (HgCl2)-induced autoimmunity. The mechanism of the latter disease has been recently partly elucidated. The aim of this study was to compare DP and HgCl2-induced autoimmunity in BN rats and to compare the mechanisms involved in both situations. A transient increase in the number of spleen cells, affecting B cells and CD4+ T cells, and an increase in serum IgE concentration, previously reported in HgCl2-induced autoimmunity, were observed during DP treatment. Autoreactive anti-class II T cells able to proliferate not only in the presence of autologous B cells but also in the presence of syngeneic normal B cells were found in DP-treated BN rats. Spontaneous regulation occurred, associated with the disappearance of autoreactive T cells. Suppressor CD8+ T cells were not involved in this phenomenon. Mechanisms involved in both the induction and the regulation of DP-induced autoimmunity seem to be quite similar to those reported in HgCl2-induced autoimmunity.

Animals↗

Lymphokines in autoimmunity--roles of interferons in systemic lupus erythematosus and other autoimmune disorders.

All healthy subjects have the capacity to produce autoantibodies markedly similar to those seen in autoimmune disease. This capacity may be activated by viruses, through the release of IFN or other mechanisms. Autoimmune disease can be induced or enhanced by interferons in mice and in humans. Circulating IFNs are very frequent in patients with autoimmune diseases and may participate in the mediation of several clinical and immunologic manifestations. IFN-induced aberrant HLA-DR expression is common on epithelial cells of target organs of many autoimmune diseases; it may present autoantigen to T-cells and initiate a cycle of self-perpetuating autoimmunity. Interaction of IFN with other lymphokines (TNF, interleukin 1, etc.) may contribute to disease development. Further understanding of the role of lymphokines in autoimmunity may provide the basis for specific therapy in the future.

Animals↗

Organ-specific autoimmune disease induced in mice by elimination of T cell subsets. V. Neonatal administration of cyclosporin A causes autoimmune disease.

Cyclosporin A (CsA), a potent immunosuppressive drug, caused organ-specific autoimmune disease, such as gastritis with anti-parietal cell autoantibodies or oophoritis with anti-oocyte autoantibodies, in BALB/c mice when the drug was administered daily for 1 wk to newborns. Administration to adult mice did not. CsA abrogated the production of L3T4+ T cells and Lyt-2+ T cells in the thymus. Consequently, these T cells were substantially depleted from the peripheral lymphoid organs, especially when the drug was administered from the day of birth. Autoimmune disease was prevented when CsA-treated newborn mice were inoculated with splenic T cells from normal syngeneic mice. However, removal of the thymus immediately after neonatal CsA treatment produced autoimmune disease with a higher incidence and in a wider spectrum of organs, i.e., thyroiditis, sialoadenitis of the salivary gland, gastritis, insulitis of the endocrine pancreas, adrenalitis, oophoritis, or orchitis. Each autoimmune disease was accompanied by the development of circulating autoantibodies specific for the corresponding organ Ag. Immunopathology of these autoimmune diseases was quite similar to that of human organ-specific autoimmune diseases.

Animals↗

[Autoimmune haemopoietic disturbances simultaneous with autoimmune thyroid diseases].

Out of 362 patients with diagnosis of autoimmune haemopathy treated in eight-year period at the Hematology centre, concomitant autoimmune thyreoideopathy was confirmed in 22 (5.52%). The most frequent was simultaneous manifestation of pernicious anemia and autoimmune thyreoiditis-Phenomenon was less frequently observed in patients with immune thrombocytopenic purpura and Graves disease. In the subgroup of patients with autoimmune hemolytic anemia, there was no evidence of simultaneous autoimmune thyreoideopathy. General opinion is that etiopathogenesis of these immunological disorders does not include unique mechanism of humoral and cellular immune response; more probable, it is the question of normal immune response regulation impairment, based on the paerticular genetic predisposition.

Anemia, Hemolytic, Autoimmune↗

[Association of Basedow's disease and autoimmune thrombopenic purpura. No effect of hyperthyroidism on antiplatelet autoimmunity].

The association between Graves' disease and autoimmune thrombocytopenic purpura is rare and yet more frequent than would be expected from a mere coincidence. The existence of an immunological disorder common to Graves' disease and autoimmune thrombocytopenic purpura and/or a direct responsibility of hyperthyroidism in the genesis of immunological disturbances resulting in autoimmune thrombocytopenic purpura are hypotheses put forward to try and explain why these two pathologies are associated. We report two cases in which the antiplatelet autoimmunity developed independently of the thyroid functional disorder, making it unlikely that hyperthyroidism played a direct role in the occurrence of the immunological disorders responsible for the autoimmune thrombocytopenic purpura. The physiopathology responsible for the Graves' disease-autoimmune thrombocytopenic purpura association remains imperfectly known. The existence of an immunological pathogenetic mechanism underlying both diseases seems to be likely; it probably acts through an antigenic determinant that is common to thyroid cells and platelets.

Adult↗

Hyperproinsulinemia segregates young adult patients with newly diagnosed autoimmune (type 1) and non-autoimmune (type 2) diabetes.

OBJECTIVE: To investigate whether measurements of proinsulin and/or intermediate proinsulin degradation products could be used to differentiate between autoimmune (type 1) and non-autoimmune (type 2) diabetes in young adults. MATERIAL AND METHODS: Total proinsulin, intact proinsulin and 32,33 split proinsulin concentrations were measured in 25 patients aged 15-34 years with type 1 diabetes, as defined by the presence of at least two positive islet autoantibodies, and in 23 antibody-negative patients of similar age with type 2 diabetes, at the time of clinical onset of diabetes and at 3-4 months thereafter. Comparisons were made with data from 25 healthy subjects matched for gender and age. RESULTS: Plasma levels of total proinsulin, intact proinsulin and 32,33 split proinsulin were significantly increased 2-3-fold in the patients with newly diagnosed type 2 diabetes as compared with the controls, both in absolute terms (p<0.0001) and when related to circulating insulin (p<0.01-0.0002). In contrast, absolute proinsulin and 32,33 split proinsulin concentrations were significantly lower in patients with onset of type 1 diabetes than in controls. When proinsulin and split proinsulin release were related to plasma insulin, however, similar ratios were found in the type 1 diabetes patients and in controls. Using the 90th percentile for total proinsulin in the control group as the cut-off, the sensitivity and specificity for differentiation between autoimmune and non-autoimmune diabetes were 87% and 92%, respectively. At 3-4 months after clinical onset of diabetes, proinsulin secretion was still 2-3 times higher in type 2 than in type 1 diabetes patients (p<0.001). CONCLUSIONS: Young adult patients with newly diagnosed type 2 diabetes display disproportionate hyperproinsulinemia, whereas proinsulin secretion appears to be normal in patients with clinical onset of type 1 diabetes. Evaluation of proinsulin and 32,33 split proinsulin concentrations may be useful as a diagnostic tool in differentiating between autoimmune and non-autoimmune diabetes in young adults, particularly in those lacking islet autoantibodies at diagnosis.

Adolescent↗

Isolated autoimmune response: definition, analysis of the prevalence in an outpatient rheumatology clinic, relationship to pre-clinical autoimmune disease and infections by hepatotropic viruses.

OBJECTIVE: To define the clinical significance of non-organ specific autoantibody positivity in patients in whom routine clinical and laboratory examinations did not detect any disease that might have caused the serological finding. METHODS: Out of 1,120 patients consecutively admitted to an outpatient rheumatology clinic, 28 were referred for the evaluation of an autoantibody positivity unrelated to the clinical status. These patients and 28 sex- and age-matched controls underwent a specific work-up with the aim of detecting any underlying infection or autoimmune disease. RESULTS: Eight of the 28 patients (28.5%) were found to be affected by a previously undetected disease: 3 chronic hepatitis C, 3 Sjögren's syndrome, and 2 autoimmune thyroiditis. The remaining 20 did not show any autoimmune or hepatic disease, although 4 of them showed active infection by HBV (n = 1) or HGV (n = 3) and 15 had had a previous infection by hepatotropic viruses (HBV, CMV or EBV). After a follow-up lasting 6-54 months, none of the last 20 patients developed any autoimmune or chronic hepatic disease. CONCLUSIONS: A diagnostic work-up is necessary in patients presenting with unexpected autoantibody positivity in order to detect an underlying pre-clinical autoimmune disease and/or unexpected hepatic infection. Patients in whom such a work-up fails to point out any condition should be further followed in order to make an early diagnosis of autoimmune disease.

Adolescent↗

Phospholipid specificity of autoimmune and drug induced lupus anticoagulants; association of phosphatidylethanolamine reactivity with thrombosis in autoimmune disease.

OBJECTIVE: To assess the phospholipid specificity of lupus anticoagulants (LAC) in autoimmune and drug induced LAC positive patients, and to determine their relevance with the clinical feature thrombosis. METHODS: Thirty-five plasma samples with LAC were tested. Of these, 22 samples were from patients with autoimmune disease: 12 had systemic lupus erythematosus (SLE) and 10 primary antiphospholipid syndrome (APS). These were compared with 13 patients with drug induced LAC. Antiphospholipid (aPL) activity was tested by inhibition of LAC activity in a modified coagulation assay using the phospholipids: egg phosphatidylethanolamine (PE), 20% phosphatidylserine/80% phosphatidylcholine (PS/PC), and 15% PS/65%PC/20%PE mixture. Anticardiolipin antibodies (aCL) were measured in all samples by ELISA. RESULTS: In the autoimmune group, 95% were positive for reactivity to PE, 68% for PS/PC, 68% for PS/PC/PE, and 77% aCL. Of the drug induced group, 69% were positive for reactivity to PE, but only 23% for PS/PC, 46% PS/PC/PE, and 23% aCL positive. In the autoimmune patient group, 64% had thrombotic episodes, all of which had anti-PE activity, and 64% had associated anti-PS activity. No drug induced patient had episodes of thrombosis. CONCLUSION: Autoimmune induced LAC may contain a broader range of phospholipid specificities than those from drug induced patients. These data thus identify another potential reason why patients with drug induced LAC appear to be at less risk of developing APS than those with autoimmune LAC.

Antibody Specificity↗

Use of intravenous gamma globulin for the treatment of autoimmune neutropenia of childhood and autoimmune hemolytic anemia.

Intravenous gamma globulin (IVIG) was used to treat autoimmune neutropenia of childhood and autoimmune hemolytic anemia, two autoimmune disorders not previously treated with this modality. Six children younger than two years of age, who presented with severe infections and persistent absolute neutrophil counts (300/mm3), were treated with 1 g of gamma globulin per kilo body weight until counts reached more than 1,000/mm3. The average response occurred with a dose of 3.0 g/kg within five to seven days and lasted an average of 14 days before counts decreased to baseline levels. Four patients with autoimmune hemolytic anemia were also treated with IVIG, 1 g/kg for five to seven days (average dose of 5 g/kg), for severe Coombs'-positive hemolytic anemia. Response of the hemolytic anemia to IVIG was excellent in one patient and good in two patients. No response occurred in the fourth patient. Response was slower in these patients than in patients treated for immune thrombocytopenic purpura (ITP). The average total amount of gamma globulin required for a response is markedly different: 1 g/kg for ITP, 3.0 g/kg for autoimmune neutropenia, and 5 g/kg for hemolytic anemia. Possible mechanisms of action include blockade of reticuloendothelial system Fc receptors, suppression of autoantibody production, and/or interference in the binding of autoantibodies to target cells.

Agranulocytosis↗

Autoimmune polyendocrinopathy syndrome type 1 (APS1) and AIRE gene: new views on molecular basis of autoimmunity.

Autoimmune polyendocrinopathy syndrome type 1 (APS1) is a monogenic autoimmune syndrome, which is caused by defect in AIRE gene on chromosome 21. Several autoimmune diseases occur in APS1 patients, often starting in first two decades of life. A gene defective in APS1, autoimmune regulator (AIRE), encodes nuclear protein involved in transcriptional processes. Recent findings in animal models indicate a critical role for AIRE in regulation of self-antigen expression in thymus. Identification of the AIRE gene, detailed characterization of molecular pathogenesis of human APS1 as well as analyses of mouse models carrying targeted interruption of Aire gene have provided new views on our understanding of molecular background of autoimmunity.

Animals↗

Autoimmune thyroid disease: new models of cell death in autoimmunity.

Autoimmunity to thyroid antigens leads to two distinct pathogenic processes with opposing clinical outcomes: hypothyroidism in Hashimoto's thyroiditis and hyperthyroidism in Graves' disease. The high frequency of these diseases and easy accessibility of the thyroid gland has allowed the identification of key pathogenic mechanisms in organ-specific autoimmune diseases. In early investigations, antibody- and T-cell-mediated death mechanisms were proposed as being responsible for autoimmune thyrocyte depletion. Later, studies on apoptosis have provided new insights into autoimmune target destruction, indicating the involvement of death receptors and cytokine-regulated apoptotic pathways in the pathogenesis of thyroid autoimmunity.

Apoptosis↗

Virus-induced autoimmunity: potential role of viruses in initiation, perpetuation, and progression of T-cell-mediated autoimmune disease.

Virus infections have been implicated in the initiation of multiple human autoimmune diseases. This article focuses on reviewing the role of viruses in initiation, progression, and perpetuation of autoimmune diseases. Various mechanisms by which virus infections can induce autoimmune responses including molecular mimicry, epitope spreading, direct bystander activation, and release of cryptic epitopes are discussed. Evidence implicating virus infections in the pathogenesis of various human autoimmune diseases is reviewed. Last, the characteristics of animal models that have been developed for the study of the potential role of viruses in the initiation and progression of autoimmune disease are reviewed.

Adult↗

Autoimmune hyperlipidemia in a child with autoimmune hepatitis.

The first reported case of a girl with a combination of autoimmune hyperlipidemia and autoimmune hepatitis is described. She presented at the age of 9 years with fever, headaches, and abnormal lipid profile. Months later, she had clinical manifestations, biochemical findings, and the histologic picture of autoimmune hepatitis. Subsequently, she also showed signs and symptoms of systemic lupus erythematosus. All of her clinical manifestations and biochemical abnormalities dramatically improved with immunosuppression. The overlapping syndrome of systemic lupus erythematosus, autoimmune hepatitis, and autoimmune hyperlipidemia is discussed.

Adolescent↗

Causal effect of three autoimmune diseases on brain functional networks and cerebrospinal fluid metabolites to underlie the pathogenesis of autoimmune psychosis: a two-sample mendelian randomization analysis.

BACKGROUND: Autoimmune diseases such as Systemic Lupus Erythematosus (SLE), Sj&#xf6;gren's Syndrome (SS), and Hashimoto's Thyroiditis (HT) frequently exhibit neuropsychiatric manifestations, including cognitive impairment, depression, anxiety, and so on, yet the exact pathogenesis underlying this association remain incompletely understood. Dysfunction of brain resting-state functional networks and cerebrospinal fluid (CSF) metabolite disturbances have been widely reported in psychiatric disorders. However, the application of resting-state functional magnetic resonance imaging (rsfMRI) and CSF metabolomics in the diagnosis and monitoring of autoimmune psychosis is still limited. METHODS: A two-sample Mendelian randomization (MR) analysis was performed to investigate the causal relationships between three autoimmune diseases (SLE, SS, and HT, n&#x2009;=&#x2009;14,267 to 402,090 individuals) and 191 rsfMRI phenotypes (n&#x2009;=&#x2009;47,276 individuals), as well as 338 CSF metabolites. The genome-wide association study (GWAS) of three autoimmune diseases was used as the exposure, whereas rsfMRI phenotypes and 338 CSF metabolites were treated as the outcome. Inverse variance weighted (IVW) with P value&#x2009;<&#x2009;0.05 was regarded as the primary approach for calculating causal estimates. Additionally, the false discovery rate (FDR)-adjusted P value (PFDR)&#x2009;<&#x2009;0.05 was utilized to account for multiple testing. MR Egger method, weighted median method, simple mode method and weighted mode method were used for sensitive analysis. RESULTS: Our analyses identified 5 causal relationships between SLE and the 191 rsfMRI phenotypes, 48 between SS and the 191 rsfMRI phenotypes, and 4 between HT and the 191 rsfMRI phenotypes. Additionally, we found 8 causal relationships between HT and CSF metabolites. Furthermore, all three diseases were significantly associated with the temporal lobe and triple networks (default mode network (DMN), salience network (SN), and central executive network (CEN)), which are the core brain regions and functional networks for cognition. Following FDR correction, 6 causal relationships between SS and the 191 rsfMRI phenotypes were further validated. CONCLUSIONS: Our study pinpoints important brain functional networks and CSF metabolites potentially implicated in the pathogenesis of psychiatric disorders associated with autoimmune diseases and highlights critical brain regions for the development of novel therapeutics.

Humans↗

Autoimmune and non-autoimmune thyroid diseases have different patterns of cellular HLA class II expression.

CONTEXT: Surface HLA-DR antigen is usually only expressed by antigen-presenting cells (APC). In autoimmune thyroid disease, follicle cells function as APC, thus expressing HLA-DR. However, non-autoimmune thyroid diseases may also express surface class II antigens. OBJECTIVE: To evaluate the presence and pattern of HLA class II expression in autoimmune and non-autoimmune thyroid disorders. DESIGN: Retrospective: histopathological and immunohistochemical analysis. LOCATION: Referral center, university hospital. SAMPLE: Ten histologically normal thyroids, 11 Graves' disease, 7 Hashimoto's thyroiditis, 10 atoxic multinodular goiter and 3 toxic adenomas were analyzed by immunohistochemistry, using a monoclonal antibody anti-HLA-DR. MAIN MEASUREMENTS: The presence of these antigens in thyroid follicular cells and their relation to inflammatory infiltrate was evaluated. The pattern of HLA-DR expression in thyroid follicular cells was analyzed: membrane, cytoplasmic or both. RESULTS: Although HLA-DR antigens were sparsely present in one of the 8 normal thyroids, in 6 of the 9 atoxic multinodular goiter and in 2 of the 3 toxic adenomas a net positivity could be seen in large areas. In all 5 Hashimoto's thyroiditis and in 7 of the 10 Graves' disease cases. This expression occurred in follicle cells either in contact with inflammatory cells or not. In non-autoimmune thyroid disease, HLA-DR positivity was essentially cytoplasmic, whereas in Graves' disease and Hashimoto thyroiditis it was mainly in cell membranes. CONCLUSIONS: It is suggested that the HLA class II expression on the surface of follicle cells could be related to auto-antigen presentation to the immune system by these cells, leading to inflammation.

Antibodies, Monoclonal↗