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PubMed2004

A cardiac myosin-specific autoimmune response is induced by immunization with Trypanosoma cruzi proteins.

Trypanosoma cruzi is the protozoan parasite that causes Chagas' heart disease, a potentially fatal cardiomyopathy prevalent in Central and South America. Infection with T. cruzi induces cardiac myosin autoimmunity in susceptible humans and mice, and this autoimmunity has been suggested to contribute to cardiac inflammation. To address how T. cruzi induces cardiac myosin autoimmunity, we investigated whether immunity to T. cruzi antigens could induce cardiac myosin-specific autoimmunity in the absence of live parasites. We immunized A/J mice with a T. cruzi Brazil-derived protein extract emulsified in complete Freund's adjuvant and found that these mice developed cardiac myosin-specific delayed-type hypersensitivity (DTH) and autoantibodies in the absence of detectable cardiac damage. The induction of autoimmunity was specific since immunization with extracts of the related protozoan parasite Leishmania amazonensis did not induce myosin autoimmunity. The immunogenetic makeup of the host was important for this response, since C57BL/6 mice did not develop cardiac myosin DTH upon immunization with T. cruzi extract. Perhaps more interesting, mice immunized with cardiac myosin developed T. cruzi-specific DTH and antibodies. This DTH was also antigen specific, since immunization with skeletal myosin and myoglobin did not induce T. cruzi-specific immunity. These results suggest that immunization with cardiac myosin or T. cruzi antigen can induce specific, bidirectionally cross-reactive immune responses in the absence of detectable cardiac damage.

Animals↗

PubMed2002

Autoimmunity in human primary immunodeficiency diseases.

Human primary immunodeficiency diseases are experiments of nature characterized by an increased susceptibility to infection. In many cases, they are also associated with troublesome and sometimes life-threatening autoimmune complications. In the past few years, great strides have been made in understanding the molecular basis of primary immunodeficiencies, and this had led to more focused and successful treatment. This review has 3 aims: (1) to highlight the variety of autoimmune phenomena associated with human primary immunodeficiency diseases; (2) to explore how primary immunodeficiencies predispose patients to autoimmune phenomena triggered by opportunistic infections; and (3) to consider the rationale for the current treatment strategies for autoimmune phenomena, specifically in relation to primary immunodeficiency diseases. Reviewing recent advances in our understanding of the small subgroup of patients with defined causes for their autoimmunity may lead to the development of more effective treatment strategies for idiopathic human autoimmune diseases.

Autoimmune Diseases↗

PubMed2026

Divergent autoimmune genetic landscapes in diabetic and non-diabetic individuals.

BACKGROUND: Type 2 diabetes (T2D) and autoimmune diseases are complex disorders shaped by genetic, immunological, and environmental factors. However, differences in genetic susceptibility to autoimmune disorders between diabetic and non-diabetic individuals remain poorly understood, particularly within the Indian population. This study aimed to compare polygenic susceptibility to multiple autoimmune diseases between individuals with and without T2D from Gujarat, India. RESULTS: Polygenic risk scores were evaluated for eleven autoimmune diseases in 474 individuals, including 99 diabetics and 375 non-diabetics. Significant differences were observed for systemic lupus erythematosus and rheumatoid arthritis. Individuals with diabetes showed a higher genetic risk for systemic lupus erythematosus, whereas non-diabetic individuals exhibited a higher genetic risk for rheumatoid arthritis. Pathway enrichment analysis of disease-associated genetic variants revealed significant involvement of immune-related pathways, including antigen processing and presentation, T-helper cell differentiation, and immune responses to viral infections. CONCLUSIONS: The findings reveal disease-specific differences in genetic susceptibility to autoimmune disorders between diabetic and non-diabetic individuals. These results highlight the complex immunogenetic relationship between type 2 diabetes and autoimmune diseases and provide insight into shared and distinct immune pathways within an Indian population. Such information may support future efforts in risk stratification and precision medicine approaches for immune-related comorbidities in diabetes.

Humans↗

PubMed2026

Genome-wide etiology analysis of autoimmune hypothyroidism supports somatic mutations of at-risk DNA as the underlying cause.

Autoimmune hypothyroidism (AIHT) is the most common autoimmune disease. Through an unidentified mechanism, the immune system attacks the thyroid gland, destroys thyroid follicular cells, and causes hypothyroidism. A new theory poses that all DNA is continuously damaged and, as a result, is exposed to somatic mutations at a constant rate. Based on this theory, several assumptions related to epidemiology and DNA sequence can be made. These have been summarized as a method called genome-wide etiology analysis (GWEA) to facilitate the interpretation of GWAS results of autoimmune diseases. Here, GWEA is applied to AIHT. The results show that existing epidemiological and genomic data of AIHT adhere to the principles of GWEA. Therefore, AIHT appears to be the result of somatic mutations in people at risk for the disease. AIHT develops once sufficient mutations create a new "autoimmune pathway" driven by non-self-signal and supported by neopeptide formation and signal amplification. Given the random nature of somatic mutations throughout life, the new theory explains why some people with AIHT develop additional autoimmune diseases, why family members may develop a range of non-AIHT autoimmune diseases, why the age of onset cannot be predicted, and why AIHT is transferred to the following generations through dominant inheritance with delayed, incomplete penetrance.

Humans↗

PubMed2004

Profiles of gene expression in human autoimmune disease.

Human autoimmune diseases arise from complex interactions between genetic and environmental factors, result from immune attack upon target tissues, and affect 3-5% of the population. We compared gene expression profiles (>4000 genes) in the peripheral blood mononuclear cells of normal individuals after immunization to individuals with four different autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus, and multiple sclerosis). All autoimmune individuals, including unaffected first-degree relatives, share a common gene expression profile that is completely distinct from the immune profile. Therefore, this expression pattern is not simply a recapitulation of the immune response to nonself, is not a result of the disease process, and results, as least in part, from genetic factors. Surprisingly, these genes are clustered in chromosomal domains suggesting there is some genome-wide logic to this unique expression pattern. These data argue that that there is a constant pattern of gene expression in autoimmunity that is independent of the specific autoimmune disease and clinical parameters associated with any individual autoimmune disease.

Autoimmune Diseases↗

PubMed2003

Rational design of peptide vaccines for autoimmune disease: harnessing molecular recognition to fix a broken network.

Autoreactive T-cells and antibodies are found at low levels in normal individuals and are thought to be kept at bay by regulatory T-cells and a network of idiotypic and anti-idiotype-bearing antigen receptors on lymphocytes as well as idiotypic anti-idiotypic antibodies. Disruption of this network by genetic, environmental and unknown factors is thought to result in autoimmune diseases. An obvious, ideal and specific therapy for such disorders would be to harness this regulatory network to re-establish immunologic homeostasis. In practice, however, this is not an easy task as most autoimmune diseases involve polyclonal responses to self antigen. Thus, we are faced with the conundrum of not knowing which autoreactive idiotype-bearing antibody or antigen receptor(s) to target in order to restore or induce network regulatory function. The thesis of this review is that understanding a fundamental property governing peptide/protein shape can be used in part to circumvent the problems of self reactivity and polyclonality in autoimmune disorders. More specifically, an algorithm has been developed to design peptide vaccines with shapes that are thought to be complementary in contour to self epitopes which seem to be the focus of autoimmunity. In theory, such complementary shapes should be engendered in certain autoreactive antigen receptors--these complementary constructs consequently represent receptor mimetics. By targeting an immune response against such mimetics, one generates a polyclonal anti-idiotype response that matches the complexity of the autoimmune response itself. This article will describe the algorithm for vaccine design, summarize the in vitro and in vivo evidence for its efficacy and discuss possible therapeutic utility in human autoimmune diseases.

Algorithms↗

PubMed1993

Autoimmune responses as assessed by hypergammaglobulinemia and the presence of autoantibodies in patients with chronic hepatitis C.

We investigated autoimmunity, as assessed by hypergammaglobulinemia and the presence of autoantibodies including anti-nuclear antibodies (ANA) and anti-liver membrane antibodies (LMA), in 149 patients with chronic hepatitis C, 55 patients with chronic hepatitis B and 11 patients with autoimmune hepatitis. There was no significant difference in the incidence of these autoantibodies between chronic hepatitis C and chronic hepatitis B. Nine patients with chronic hepatitis C satisfied the serological criteria of autoimmune hepatitis (ANA positive and gammaglobulin or serum IgG greater than 2500 mg/dl), but none of the patients with chronic hepatitis B met the criteria. This suggests that autoimmunity is greater in chronic hepatitis C than in chronic hepatitis B. Of the 9 patients with chronic hepatitis C, all 4 patients tested for human leukocyte antigen (HLA) phenotype had HLA-DR4, which is known to be associated with autoimmune hepatitis in Japanese patients. We believe that hepatitis C virus (HCV) infection enhances the initiation and perpetuation of autoimmunity in susceptible individuals.

Adult↗

PubMed1996

Immune network and autoimmunity.

The concept of autoimmunity is regarded as the inability of the immune system to distinguish between self and non-self. This oversimplification of the concept is far from explaining the complex and perplexing mechanisms that are postulated to lead to its development. The transition from autoimmune state, in which no corresponding clinical manifestation exist, to an autoimmune disease, is further complicated by the evidence of multiple factors that participate in the evolution of the disease state. This article is written in a stepwise manner, initially reviewing the basic elements of the immune system, which are essential to understanding the fundamental processes underlying the occurrence of autoimmunity. Subsequently, a description of the factors involved in the etiopathogenesis and the presumed triggering events leading to the emergence of autoimmune diseases are described, with special emphasis on the important role of the idiotypic network, either in the maintenance of the normal immune response, or in the breakdown of self-tolerance eventuating in the autoimmune disease.

Animals↗

PubMed2026

Multilevel Exploration of Shared Genetic Architecture Between Primary Biliary Cholangitis and Four Autoimmune Diseases.

INTRODUCTION: Primary Biliary Cholangitis (PBC) frequently coexists with various autoimmune diseases, such as Multiple Sclerosis (MS), Psoriasis (PS), Rheumatoid Arthritis (RA), and Sjögren's Syndrome (SS). Understanding the genetic associations between these diseases is crucial for providing deeper insights into their shared pathogenic mechanisms and comorbidity patterns. METHODS: This study utilized genome-wide association study summary data of PBC and four autoimmune diseases (MS, PS, RA, and SS). A multi-stage analytical pipeline was employed to systematically investigate the genetic associations between the diseases. The analytical approach consisted of three stages: first, linkage disequilibrium score regression and high-definition likelihood methods were applied to estimate overall genetic correlations between the diseases; second, local genetic correlation analysis was conducted to pinpoint genetic signals in specific chromosomal regions; third, conditional/conjunctional false discovery rate (cond/conjFDR) algorithms were used to quantitatively assess genetic overlap and identify shared susceptibility loci. RESULTS: Genome-wide analysis revealed significant genetic associations between PBC and the four autoimmune diseases (MS, PS, RA, and SS). Regional analysis showed local genetic correlations across various chromosomal segments. cond/conjFDR analysis confirmed genetic intersections among the diseases and identified several critical genetic polymorphic loci that influence disease susceptibility. DISCUSSION: This study comprehensively delineates the shared genetic architecture underlying PBC and four autoimmune diseases through integrative analyses of multiple genome-wide approaches. The results highlight strong genetic correlations, particularly between PBC and MS, PS, RA, and SS, and identify key shared susceptibility genes, including CLEC16A, CD58, CD86, STAT4, IRF5, TYK2, and TNFAIP3, which collectively mediate immune dysregulation through autophagy, cytokine signaling, and NF-κB pathways. These findings not only extend current understanding of the molecular mechanisms driving autoimmune comorbidity but also provide potential genetic targets for future functional validation and therapeutic exploration. CONCLUSION: This study provides comprehensive genomic evidence for the genetic connections between PBC and the four autoimmune diseases (MS, PS, RA, and SS), offering valuable insights into the shared pathological mechanisms underlying their comorbidities.

Humans↗

PubMed2004

Natural anticoagulant proteins in the regulation of autoimmunity: potential role of protein S.

Autoimmunity results when the immune system fails to distinguish between self and non-self factors in the body. The cellular and biochemical mechanisms that underlie development of autoimmunity are only partly understood. One current theory is that autoimmunity can result when there is a failure to clear dying cells from a tissue before they undergo lysis of the plasma membrane. That is, cells that die by apoptosis are thought to be cleared from a tissue by neighboring phagocytic cells, such as macrophages, before the cells have lost their plasma membrane integrity. This rapid removal of early apoptotic cells is thought to prevent induction of an inflammatory response to intracellular macromolecules, thereby allowing for an immunologically silent removal of the dying cells. Hence, any factor or condition that inhibits phagocytosis of early apoptotic cells may trigger or promote an autoimmune response to intracellular components. Depletion of factors required for the efficient phagocytosis of dying cells would have a similar outcome. The recent discovery that the natural anticoagulant protein S is required for efficient uptake of apoptotic cells (Anderson, H.A., Maylock, C.A., Williams, J.A., Paweletz, C.P., Shu, H., and Shacter, E. (2003) Nature Immunology 4, 87-91) reveals a potential new linkage between autoimmunity and coagulation systems. This article will review the dual roles of protein S as an anticoagulant and in regulating phagocytosis of apoptotic cells, with emphasis on exposing a possible novel role in regulating autoimmunity.

Apoptosis↗

PubMed2004

Reactive oxygen species in the initiation of IL-4 driven autoimmunity as a potential therapeutic target.

Helper T-lymphocytes have been shown to differentiate into two mutually regulatory subsets. Cells primarily secreting interleukin-2 (IL-2) and interferon-gamma are known as Th1 cells and mediate classical cell-mediated immune responses such as delayed-type hypersensitivity. Cells secreting interleukin-4 (IL-4) are known as Th2 cells and promote humoral immune responses, in particular the production of IgE and IgG4 (human) or IgG1 (rodents). Over-activity of either cell type can result in tissue-damaging autoimmune disease. A number of human diseases including asthma and some kidney diseases are thought to be caused by a Th-2 type autoimmune response. Study of an animal model of Th2-driven autoimmunity (mercuric chloride-induced autoimmunity in Brown Norway rats) has yielded insights into a possible role for oxidant stress in the generation of Th-2 driven autoimmune responses. Mercuric chloride probably causes oxidant stress by the generation of free-radicals, activating NK-kappaB, a transcription factor for the IL-4 gene. Treatment with the antioxidants N-acetlcysteine and desferrioxamine has been shown to suppress vasculitis and IgE production in this model. These findings suggest a possible clinical role for antioxidants in the therapy of human autoimmune disease.

Adjuvants, Immunologic↗

PubMed2006

Spots, blots, peaks and chips: proteomic approaches in autoimmune diseases.

During the past five years, investigations employing a variety of proteomic technologies have yielded a wealth of information on a number of autoimmune disorders. Animal models of autoimmune disease have been examined and have provided clues that can be useful in elucidating molecular pathways and mechanisms that play a role in autoimmune disorders. Human sera and body fluids have been analyzed and have resulted in the identification of autoantibodies that can be used as diagnostic markers in specific autoimmune diseases, and proteomic fingerprints of tissues and body fluids have resulted in the identification of individual proteins or patterns of protein expression that are deregulated in autoimmune diseases. The information provided by these proteomic studies are of diagnostic and therapeutic potential. This review provides an overview of the approaches used in the proteomic analyses of autoimmune disease.

Animals↗

PubMed1989

AIDS and autoimmunity.

While much evidence appears to support the hypothesis of AIDS being an autoimmune disease, equally impressive facts negate the theory. At most, one can presently speak only of the "autoimmune features" of this very complex syndrome. AIDS most strikingly presents with various autoantibodies including those directed against both red and white blood cells. These antibodies appear to be - at least in part - responsible for some of the autoimmune features of the disease. Several clinical and serological similarities exist between AIDS and the "classic" autoimmune disease SLE. In fact, following the isolation of HIV, researchers once again began searching for a viral etiology of SLE. It appears that while autoimmune mechanisms may explain some of the clinical and serologic manifestations of the disease, not enough evidence exists as yet to decidedly point either for or against its classification as an autoimmune disease.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Autoimmune thyroid disease: immunological, pathological, and clinical aspects.

Autoimmune thyroiditis, most notably Hashimoto's thyroiditis, appears to be increasing in prevalence and is now more easily detected by sensitive laboratory tests and more invasive procedures such as fine needle aspiration. During the last decade, marked progress has been made in the understanding of these diseases. There is a greater awareness of the interaction between the humoral and cell-mediated arms of the immune system in autoimmune thyroiditis. Recent studies implicate a subpopulation of suppressor T lymphocytes which have an antigen-specific defect, resulting in their suboptimal interaction with the helper T lymphocytes and subsequent autoimmune manifestations. There is some evidence that thyroid epithelial cells which inappropriately express HLA-DR may enhance presentation of thyroid antigens to the immune system, possibly significant in the initiation or enhancement of the autoimmune response. The presence of various antithyroid autoantibodies allows the use of laboratory assays to confirm the clinical diagnosis and predict the results of treatment. There appears to be predisposing genetic factors in the development of autoimmune thyroiditis, with some geographical and racial differences. Environmental factors, most notably dietary intake of iodine, have also been implicated in the pathogenesis of Hashimoto's thyroiditis. Several animal models have been developed addressing such issues. Ongoing studies in the areas of postpartum thyroiditis and childhood thyroiditis are helpful in clarifying their relationship with Hashimoto's thyroiditis. Graves' disease and postpartum thyroiditis are being investigated as possible causes of postpartum depression. The association of Hashimoto's thyroiditis and carcinoma of the thyroid gland is still controversial, but its relationship with malignant lymphoma is now well accepted. Thus, although the pathogenesis of autoimmune thyroiditis remains elusive, there has been significant refinement of the clinical diagnosis, and immunological abnormalities of specific intrathyroidal lymphocytes have been identified. Hopefully, these new areas of knowledge will assist in the treatment of these diseases and in the prevention of the development of malignant lymphomas of the thyroid gland.

Animals↗

PubMed2006

Autoreactive T cells mediate NK cell degeneration in autoimmune disease.

Emerging evidence indicates that NK cells play an important and complex role in autoimmune disease. Humans with autoimmune diseases often have reduced NK cell numbers and compromised NK cell functions. Mechanisms underlying this NK cell degeneration and its biological significance are not known. In this study we show that, in an experimental model of human autoimmune myasthenia gravis induced by a self-Ag, the acetylcholine receptor, NK cells undergo proliferation during the initiation of autoimmunity, followed by significant degeneration associated with the establishment of the autoreactive T cell response. We show that NK cell degeneration was mediated by IL-21 derived from autoreactive CD4(+) T cells, and that acetylcholine receptor-immunized IL-21R-deficient mice, with competent NK cells, developed exacerbated autoimmunity. Thus, NK cell degeneration may serve as a means evolved by the immune system to control excessive autoimmunity.

Animals↗

PubMed2006

Induction of autoimmunity by expansion of autoreactive CD4+CD62Llow cells in vivo.

The prerequisites of peripheral activation of self-specific CD4(+) T cells that determine the development of autoimmunity are incompletely understood. SJL mice immunized with myelin proteolipid protein (PLP) 139-151 developed experimental autoimmune encephalomyelitis (EAE) when pertussis toxin (PT) was injected at the time of immunization but not when injected 6 days later, indicating that PT-induced alterations of the peripheral immune response lead to the development of autoimmunity. Further analysis using IA(s)/PLP(139-151) tetramers revealed that PT did not change effector T cell activation or regulatory T cell numbers but enhanced IFN-gamma production by self-specific CD4(+) T cells. In addition, PT promoted the generation of CD4(+)CD62L(low) effector T cells in vivo. Upon adoptive transfer, these cells were more potent than CD4(+)CD62L(high) cells in inducing autoimmunity in recipient mice. The generation of this population was paralleled by higher expression of the costimulatory molecules CD80, CD86, and B7-DC, but not B7-RP, PD-1, and B7-H1 on CD11c(+)CD4(+) dendritic cells whereas CD11c(+)CD8alpha(+) dendritic cells were not altered. Collectively, these data demonstrate the induction of autoimmunity by specific in vivo expansion of CD4(+)CD62L(low) cells and indicate that CD4(+)CD62L(low) effector T cells and CD11c(+)CD4(+) dendritic cells may be attractive targets for immune interventions to treat autoimmune diseases.

Adjuvants, Immunologic↗

PubMed2005

Heat shock proteins in autoimmune diseases.

Heat shock proteins (hsp's) are among the most conserved proteins in evolution. They have been identified as important pathogen-related antigens as well as autoantigens suitable for construction of novel vaccines. The high evolutionary homology of hsp's has raised the question about the safety of such vaccines. Experimental and clinical observations have confirmed that hsp proteins are involved in the regulation of some autoimmune disease such as autoimmune arthritis, type 1 diabetes mellitus, atherosclerosis, multiple sclerosis, and other autoimmune reactions. It has been shown in experimental animals that some hsp proteins (especially hsp60, hsp70, and hsp10) can either induce or prevent autoimmune reactions depending on the circumstances. This article discusses the involvement of hsp proteins in the etiology of autoimmune diseases and it presents promising experimental data on the effects of immunization with hsp proteins in the prevention and therapy of autoimmune diseases.

Animals↗

PubMed1975

Thyrogastric autoimmune disease. Studies on the cell-mediated immune system and histocompatibility antigens.

Cell-mediated immune responses were studied in autoimmune diseases of thyrogastric type, Hashimoto's thyroiditis and autoimmune pernicious anaemia-type gastritis. Specific cell-mediated immunity was investigated by the leucocyte migration inhibition procedure, and general cell-mediated immunity (T-cell performance) was studied by standard in vivo and in vitro tests. In thyrogastric autoimmune diseases inhibition of migration of leucocytes was induced by thyroglobulin and gastric parietal cell microsomes; under conditions of presumably low cellular sensitization, stimulation of migration was observed. There was no depression of general cell-mediated immunity, in contrast to what occurs in systemic lupus erythematosus and related autoimmune diseases. A weak association of autoimmune gastritis with HL-A3 and HL-A7 (P LESS THAN 0.05) lost significance when an appropriate correction was applied; this weakness with HL-A clearly does not explain the strong genetic component in thyroid and gastric autoimmunity.

Anemia, Pernicious↗