Genetic Predispositions and their Impact on Autoimmune Disease Pathogenesis

Cidlowski Giorgetti^*
*Correspondence: Cidlowski Giorgetti, Department of Neuroimmunology, Campus Bio-Medico University, 00128 Rome, Italy, Email:

Introduction

Autoimmune diseases (AIDs) are a complex group of disorders where the bodyâ??s immune system mistakenly targets and attacks its own tissues, leading to inflammation, damage and a variety of clinical manifestations. Examples of autoimmune diseases include rheumatoid arthritis, lupus, multiple sclerosis, type 1 diabetes and inflammatory bowel diseases, among others. The development of these diseases is influenced by both genetic and environmental factors, with genetics playing a key role in the susceptibility to and pathogenesis of autoimmune conditions. Among the most important features of autoimmune diseases are the formation of autoantibodiesâ??antibodies that target and bind to self-antigens. These autoantibodies can serve as biomarkers for diagnosing autoimmune diseases and their presence often correlates with disease activity and progression. The origins of autoantibody formation are multifaceted, involving not just genetic predispositions but also environmental triggers and immune dysregulation [1].

The development of autoimmune diseases is influenced by a complex interplay of multiple genetic factors, with significant evidence suggesting a heritable component. Twin studies, family-based studies and genome-wide association studies (GWAS) have all shown that autoimmune diseases tend to run in families, suggesting a genetic predisposition. For instance, identical twins have a much higher concordance rate for autoimmune diseases compared to fraternal twins, supporting the notion of genetic susceptibility. However, autoimmune diseases are rarely caused by a single gene mutation. Instead, they result from the interaction of multiple genetic variants, each contributing a small effect to disease susceptibility. The heritability of autoimmune diseases is often high, but the exact number of genetic variants involved and their specific roles in disease initiation remain an area of active research [2].

Description

Epigenetic modifications, which refer to changes in gene expression that do not involve alterations in the DNA sequence itself, are also believed to play a significant role in autoimmune disease development. Environmental factors such as infections, smoking, diet and exposure to certain chemicals can trigger epigenetic changes that either activate or silence specific genes involved in immune regulation. These environmental triggers can interact with an individualâ??s genetic predisposition to increase the risk of developing autoimmune diseases. For example, infections with certain viruses, such as Epstein-Barr virus (EBV), have been linked to an increased risk of autoimmune diseases like multiple sclerosis and systemic lupus erythematosus. The molecular mimicry theory suggests that the immune system may mistakenly target self-antigens that resemble pathogen-derived antigens, contributing to autoimmunity. Furthermore, the hygiene hypothesis proposes that a lack of early childhood exposure to infections and microbes can result in an overactive immune response, increasing susceptibility to autoimmune diseases [3].

Autoantibodies are antibodies produced by the immune system that target the bodyâ??s own tissues or cells. The formation of autoantibodies is a hallmark feature of many autoimmune diseases. While the exact mechanisms of autoantibody generation remain incompletely understood, genetic factors play a central role in their formation. In autoimmune diseases, the immune system typically produces autoantibodies that target specific cellular components, such as proteins, nucleic acids, or phospholipids. These autoantibodies can be detected in the blood and are often used as diagnostic markers for autoimmune diseases. One of the most well-known autoantibodies is Rheumatoid Factor (RF), which targets the Fc portion of immunoglobulin G (IgG). Additionally, anti-citrullinated protein antibodies (ACPAs) are commonly found in patients with rheumatoid arthritis and are highly specific for the disease. The genetic predisposition to developing these autoantibodies is closely linked to HLA-DRB1 alleles. In SLE, the production of autoantibodies is a defining feature. Common autoantibodies include antinuclear antibodies (ANAs), anti-dsDNA and anti-Smith (Sm) antibodies, which target various nuclear components. Genetic risk factors such as variations in the IRF5, STAT4 and other immune-related genes contribute to the dysregulation of immune responses and the development of these autoantibodies [4].

Autoantibody formation involves a breakdown of immune tolerance, which normally prevents the immune system from attacking self-antigens. The processes by which this tolerance is disrupted are still the subject of much research, but several key mechanisms are thought to contribute to autoantibody generation. During immune development in the thymus (for T cells) and bone marrow (for B cells), autoreactive lymphocytes are normally eliminated or rendered inactive in a process called central tolerance. Genetic mutations or environmental factors that disrupt this process can result in the survival of autoreactive cells, which may then produce autoantibodies. Failure of Peripheral Tolerance: Even if autoreactive lymphocytes escape central tolerance, the immune system employs additional mechanisms to prevent their activation in peripheral tissues. These mechanisms include regulatory T cells (Tregs) and inhibitory receptors on B and T cells. Genetic defects that impair peripheral tolerance can lead to the activation of autoreactive B cells and the production of autoantibodies. Epitope Spreading: In some autoimmune diseases, initial autoantibodies may target a specific self-antigen, but over time, the immune response can spread to other self-antigens, leading to the formation of multiple autoantibodies. This phenomenon, known as epitope spreading, is thought to contribute to the chronicity and progression of autoimmune diseases [5].

Conclusion

Autoimmune diseases are multifactorial disorders with a complex genetic architecture. Genetic susceptibility plays a pivotal role in the development of autoimmune diseases, with key genes involved in immune regulation contributing to both disease susceptibility and autoantibody formation. The HLA region, immune checkpoint genes such as CTLA-4 and cytokine signaling genes like STAT4 and IRF5 are just a few of the many genetic loci that influence autoimmune disease risk. Autoantibodies, the hallmark of autoimmune diseases, are the result of immune dysregulation, which can be triggered by a combination of genetic, epigenetic and environmental factors. These autoantibodies not only serve as diagnostic tools but also play a key role in the pathogenesis of many autoimmune conditions. Understanding the genetic and molecular mechanisms behind autoantibody formation is critical for the development of targeted therapies that can modulate immune responses and treat autoimmune diseases more effectively.

Acknowledgement

None.

Conflict of Interest

None.

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