Learning Objectives
By the end of this section, you will be able to:
- Define autoimmune disease and identify common pathophysiology of autoimmune disease
- Recognize common autoimmune disorders
The immune system is a network of cells, tissues, and organs that function to protect its host from viruses, bacteria, and other malignancies. To do this work, the immune system must be able to distinguish between “self” and “nonself”—that is, between the body’s own, healthy components and threats to its health. With autoimmunity, the immune system fails at this fundamental task; it mistakenly targets and attacks the body’s own healthy tissues, organs, and cells. The exact cause of this immune malfunction is unknown. It is likely to have a genetic predisposition. Autoimmunity can affect any part of the body and weaken its ability to function; it can even be life-threatening (U.S. Department of Health and Human Services, 2022).
Pathophysiology of Autoimmune Disease
There are several types of autoimmune disorders. While the exact cause of any type is unknown, all such disorders stem from the same fundamental error: the immune system misidentifies the body’s own tissues as “foreign” rather than as its “self.” Scientists have learned that many autoimmune disorders are characterized by irregular B- and T-cell reactivity to the normal components of the host. Recall that T-helper cells stimulate B cells to produce autoantibodies, and cytotoxic T cells kill or damage potential threats. Mutations of B and T cells may interrupt their normal abilities to recognize foreign antigens and lead to autoimmune disorders.
The autoantibodies, a critical diagnostic finding for autoimmune disease, form immune complexes that deposit within tissues and activate the complement system, which produces inflammation. When there is a pathogen to fight, this response is helpful. But when it is turned on the body, it damages healthy tissue. In some autoimmune conditions, the complexes start in a particular organ because the response has been triggered by a mix-up involving damaged or compromised pieces of genetic material (the acids that make up DNA and RNA). Autoantibodies may also bind to molecules in the blood, which can trigger an immune response via the complement system (Pisetsky, 2023).
According to the American Autoimmune Related Diseases Association, 50 million Americans have one or more autoimmune diseases (2019). This translates to one in five Americans being diagnosed with an autoimmune disorder. Of those affected, 75 percent are women.
Link to Learning
The American Autoimmune Related Diseases Association has a flier that provides facts about autoimmune disorders, including statistics, types, and potential causes and treatments.
Common Autoimmune Disorders
There are more than 100 autoimmune disorders, affecting a wide variety of body parts and systems. While there are important distinctions to be made among them, the nurse will find that they share some commonalities in presentation, diagnosis, and treatment. The signs and symptoms of autoimmune disease can be widespread as well as specific to the organ system(s) being targeted. Nonetheless, nurses will often note general signs and symptoms of inflammation, and assessments for these manifestations, including a physical exam, blood tests, and imaging, are common elements of the diagnostic process. Nursing interventions that are intended to help manage inflammation and its consequences, which may include counseling patients about taking preventive steps to avoid flare-ups as well as providing patient education and ongoing support, will be common.
Many autoimmune diseases have complex disease processes that are discussed in greater detail in other chapters. Table 29.4 describes the pathogenesis of common autoimmune disorders of the endocrine, hematologic, cardiac, gastrointestinal, integumentary, and musculoskeletal systems.
| Disorder | Pathogenesis |
|---|---|
| Endocrine System | |
| Type 1 diabetes mellitus | In patients with this disorder, the body’s immune system destroys the insulin-producing islet cells in the pancreas. Because the body depends on insulin to move sugar from the bloodstream into cells, patients can develop life-threatening hyperglycemia (Shimura & Kobayashi, 2004). |
| Graves disease | Thyroid-stimulating hormone signals the thyroid to make thyroid hormone as the body needs it. With Graves disease, autoantibodies are activated that stimulate thyroid hormone synthesis and secretion as well as thyroid growth, resulting in a goiter (Shimura & Kobayashi, 2004). |
| Hashimoto disease | This disorder causes antithyroid antibodies to form and attack thyroid tissue, causing fibrosis. This is thought to be due to the infiltration of lymphocytes and cytokines (Mincer & Jialal, 2022). |
| Hematologic and Cardiac System | |
| Idiopathic thrombocytopenic purpura | With this disorder, the macrophages of the immune system attack and destroy platelets, which the body needs to control clotting. The resulting deficiency can lead to easy bruising and internal bleeding (Olsson et al., 2013). |
| Autoimmune hemolytic anemia | This disorder causes anti-erythrocyte autoantibodies to destroy erythrocytes at a rate faster than the bone marrow can produce new red blood cells (Barcellini, 2015). |
| Rheumatic heart disease | Streptococci bacteria can cause rheumatic fever. Rheumatic heart disease results from valvular damage caused by an abnormal immune response to Streptococcus pyogenes infection (Dass & Kanmanthareddy, 2023). |
| Gastrointestinal System | |
| Inflammatory bowel disease (Crohn disease and ulcerative colitis) | Inflammatory bowel disease is driven by the T-cell response. The dysfunctions of the immune pathways leading to Crohn disease are considered to be driven by T-helper-1 cells (cell-mediated immune cells) (Zhang & Li, 2014). |
| Celiac disease | Gluten is a protein found mainly in wheat flour. With this disorder, gluten-derived peptides initiate an altered immune response. The CD4 T lymphocytes trigger a chain of altered immune reactions that lead to chronic inflammation of the small intestine (Parzanese et al., 2017). |
| Irritable bowel syndrome | Changes in mucosal immunocytes, mast cells, and microbiota are thought to be due to infections such as gastritis or to psychological stress. These changes can lead to inflammation characterized by increased production of cytokines, altered population of circulating cells, and mucosal infiltration of immune cells (Saha, 2014). |
| Integumentary System | |
| Psoriasis | The inflammation characteristic of this skin disorder is due to disturbances in the immune response that lead to uncontrolled keratinocyte proliferation and dysfunctional differentiation. Psoriatic plaque is composed of macrophages, T cells, neutrophils, and dermal dendritic cells (Rendon & Schäkel, 2019). |
| Scleroderma | With this disorder, the immune system triggers cells to produce too much collagen, which is deposited into organs and skin, causing hardening and thickening of the affected areas. This is thought to be due to an altered balance of the innate and acquired immune systems that leads to an overabundance of cytokines, chemokines, and autoantibodies that stimulate the activation of fibroblasts (Rosendahl et al., 2022). |
| Musculoskeletal System | |
| Rheumatoid arthritis | The pathogenesis of this disorder involves many types of cells, including macrophages, T and B cells, fibroblasts, chondrocytes, and dendritic cells. It is likely caused by environmental triggers at the mucosal surfaces that induce peptidyl arginine deiminases, which modify arginine to citrulline. These modified proteins are then presented to T cells after being processed by dendritic cells. Vascular permeability is increased in the synovium that triggers synovial cells, leading to inflammation in the joints (Firestein & Guma, 2023). |
| Multiple sclerosis | The cause of this disorder is multifactorial, so the exact pathogenesis is unclear. Genetic predisposition and environmental factors trigger an immune response that leads to neuronal cell death, nerve demyelination, and neuronal dysfunction. The inflammation of the central nervous system tissues is due to immune cell and cytokine infiltration. T-helper cells initiate interactions between antigen-presenting cells and T lymphocytes that can affect the initiation and progression of this disease (Ghasemi et al., 2017). |
| Multiple Systems | |
| Lupus | With this disorder, the immune system attacks its own tissues, causing widespread inflammation and tissue damage affecting the joints, skin, kidneys, brain, lungs, and blood vessels. The main culprits that contribute to the altered immune response are dendritic cells, neutrophils, T cells, B cells, complements, cytokines, immune complexes, and kinases of the intracellular matrix (Pan et al., 2020). |