User:Petermgrund/Autoimmune diseases

An autoimmune disease is a condition that results from an anomalous response of the immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved.

Symptoms of autoimmune diseases can significantly vary, primarily based on the specific type of the disease and the body part that it affects. Symptoms are often diverse and can be fleeting, fluctuating from mild to severe, and typically comprise low-grade fever, feeling tired, and general malaise. However, some autoimmune diseases may present with more specific symptoms such as joint pain, skin rashes (e.g., urticaria), or neurological symptoms.

The exact causes of autoimmune diseases remain unclear and are likely multifactorial, involving both genetic and environmental influences. Autoantibodies are a hallmark of most autoimmune disorders. While some diseases like lupus exhibit familial aggregation, suggesting a genetic predisposition, other cases have been associated with infectious triggers or exposure to environmental factors, implying a complex interplay between genes and environment in their etiology.

Some of the most common diseases that are generally categorized as autoimmune include celiac disease, type 1 diabetes, Graves' disease, inflammatory bowel diseases (such as Crohn's disease and ulcerative colitis), multiple sclerosis, alopecia areata, Addison's disease, pernicious anemia, psoriasis, rheumatoid arthritis, and systemic lupus erythematosus. Diagnosing autoimmune diseases can be challenging due to their diverse presentations and the transient nature of many symptoms.

Treatment modalities for autoimmune diseases vary based on the type of disease and its severity. Therapeutic approaches primarily aim to manage symptoms, reduce immune system activity, and maintain the body's ability to fight diseases. Nonsteroidal anti-inflammatory drugs (NSAIDs) and immunosuppressants are commonly used to reduce inflammation and control the overactive immune response. In certain cases, intravenous immunoglobulin may be administered to regulate the immune system. Monoclonal antibodies have emerged as a promising therapeutic. Their unique ability to modulate the immune response in a precise and targeted manner can, for some conditions, surpass that of traditional immunosuppressants. Despite these treatments often leading to symptom improvement, they usually do not offer a cure and long-term management is often required.

In terms of prevalence, approximately 24 million people, or roughly 7.5% of the population, in the United States are affected by an autoimmune disease. Women are more commonly affected than men. Autoimmune diseases predominantly begin in adulthood, although they can start at any age. The initial recognition of autoimmune diseases dates back to the early 1900s, and since then, advancements in understanding and management of these conditions have been substantial, though much more is needed to fully unravel their complex etiology and pathophysiology.

Signs and symptoms


Autoimmune diseases represent a vast and diverse category of disorders that, despite their differences, share some common symptomatic threads. These shared symptoms occur as a result of the body's immune system mistakenly attacking its own cells and tissues, causing inflammation and damage. However, due to the broad range of autoimmune diseases, the specific presentation of symptoms can significantly vary based on the type of disease, the organ systems affected, and individual factors such as age, hormonal status, and environmental influences. Furthermore, it's important to note that an individual may simultaneously have more than one autoimmune disease (known as polyautoimmunity), further complicating the symptomatology.

Generally, symptoms that are commonly associated with autoimmune diseases include:
 * fatigue
 * low-grade fever
 * malaise (a general feeling of discomfort or unease)
 * muscle aches
 * joint pain
 * skin rashes

These symptoms often reflect the body's systemic inflammatory response. However, their occurrence and intensity can fluctuate over time, leading to periods of heightened disease activity, referred to as flare-ups, and periods of relative inactivity, known as remissions.

The specific presentation of symptoms largely depends on the location and type of autoimmune response. For instance, in rheumatoid arthritis, an autoimmune disease primarily affecting the joints, symptoms typically include joint pain, swelling, and stiffness. On the other hand, type 1 diabetes, which results from an autoimmune attack on the insulin-producing cells of the pancreas, primarily presents with symptoms related to high blood sugar, such as increased thirst, frequent urination, and unexplained weight loss.

Commonly affected areas in autoimmune diseases include blood vessels, connective tissues, joints, muscles, red blood cells, skin, and endocrine glands such as the thyroid gland (in diseases like Hashimoto's thyroiditis and Graves' disease) and the pancreas (in type 1 diabetes). The impacts of these diseases can range from localized damage to certain tissues, alteration in organ growth and function, to more systemic effects when multiple tissues throughout the body are affected.

The appearance of these signs and symptoms can not only provide clues for the diagnosis of an autoimmune condition, often in conjunction with tests for specific biological markers, but also help monitor disease progression and response to treatment. Ultimately, due to the diverse nature of autoimmune diseases, a multidimensional approach is often needed for the management of these conditions, taking into consideration the variety of symptoms and their impacts on individuals' lives.

Types
While it is estimated that over 80 recognized types of autoimmune diseases exist, this section provides an overview of some of the most common and well-studied forms.

Coeliac disease
Coeliac disease is an immune reaction to eating gluten, a protein found in wheat, barley, and rye. For those with the disease, eating gluten triggers an immune response in the small intestine, leading to damage on the villi, small fingerlike projections that line the small intestine and promote nutrient absorption. This explains the increased risk of gastrointestinal cancers, as the gastrointestinal tract includes the esophagus, stomach, small intestine, large intestine, rectum, and anus, all areas that the ingested gluten would traverse in digestion. The incidence of gastrointestinal cancer can be partially reduced or eliminated if a patient removes gluten from their diet. Additionally, coeliac disease is correlated with lymphoproliferative disorders.

Graves' disease
Graves' disease is an overactive thyroid condition (hyperthyroidism) that can cause symptoms like rapid heart rate, weight loss, nervousness, and irritability. The immune system attacks the thyroid gland, causing it to produce too much thyroid hormone.

Inflammatory bowel disease
Inflammatory bowel disease (IBD) encompasses conditions characterized by chronic inflammation of the digestive tract, including Crohn's disease and ulcerative colitis. In both cases, individuals with IBD lose immune tolerance for normal bacteria present in the gut microbiome. Symptoms include severe diarrhea, abdominal pain, fatigue, and weight loss. IBD is associated with cancers of the gastrointestinal tract and some lymphoproliferative cancers.

Multiple sclerosis
Multiple sclerosis (MS) is a neurodegenerative disease in which the immune system attacks myelin, a protective covering of nerve fibers in the central nervous system, causing communication problems between the brain and the rest of the body. Symptoms can include fatigue, difficulty walking, numbness or tingling, muscle weakness, and problems with coordination and balance. MS is associated an increased risk of central nervous system cancer, primarily in the brain.

Rheumatoid arthritis
Rheumatoid arthritis (RA) primarily targets the joints, causing persistent inflammation that results in joint damage and pain. It's often symmetrical, meaning that if one hand or knee has it, the other one does too. RA can also affect the heart, lungs, and eyes. Additionally, the chronic inflammation and over-activation of the immune system creates an environment that favors further malignant transformation of other cells, perhaps explaining the associations with cancer of the lungs and skin as well as the increased risk of other hematologic cancers, none of which are directly affected by the inflammation of joints.

Psoriasis and Psoriatic arthritis
Psoriasis is a skin condition characterized by the rapid buildup of skin cells, leading to scaling on the skin's surface. Inflammation and redness around the scales is common. Some individuals with psoriasis also develop psoriatic arthritis, which causes joint pain, stiffness, and swelling.

Systemic lupus erythematosus
Systemic lupus erythematosus (SLE), referred to simply as lupus, is a systemic autoimmune disease that affects multiple organs, including the skin, joints, kidneys, and the nervous system. It is characterized by a widespread loss of immune tolerance. The disease is characterized by periods of flares and remissions, and symptoms range from mild to severe. Women, especially those of childbearing age, are disproportionately affected.

Type 1 diabetes
Type 1 diabetes is a condition resulting from the immune system attacking insulin-producing beta cells in the pancreas, leading to high blood sugar levels. Symptoms include increased thirst, frequent urination, and unexplained weight loss. It's most commonly diagnosed in children and young adults.

Causes
The exact causes of autoimmune diseases remain largely unknown; however, research has suggested that a combination of genetic, environmental, and hormonal factors, as well as certain infections, may contribute to the development of these disorders.

The human immune system is equipped with several mechanisms to maintain a delicate balance between defending against foreign invaders and protecting its own cells. To achieve this, it generates both T cells and B cells, which are capable of reacting with self-proteins. However, in a healthy immune response, self-reactive cells are generally either eliminated before they become active, rendered inert via a process called anergy, or their activities are suppressed by regulatory cells.

Genetics
A familial tendency to develop autoimmune diseases suggests a genetic component. Some conditions, like lupus and multiple sclerosis, often occur in several members of the same family, indicating a potential hereditary link. Additionally, certain genes have been identified that increase the risk of developing specific autoimmune diseases.

Genetic predisposition
Evidence suggests a strong genetic component in the development of autoimmune diseases. For instance, conditions such as lupus and multiple sclerosis frequently appear in multiple members of the same family, signifying a potential hereditary link. Furthermore, certain genes have been identified that augment the risk of developing specific autoimmune diseases.

Experimental methods like genome-wide association studies (GWAS) have proven instrumental in pinpointing genetic risk variants potentially responsible for autoimmune diseases. For example, these studies have been used to identify risk variants for diseases such as Type 1 diabetes and Rheumatoid arthritis.

In twin studies, autoimmune diseases consistently demonstrate a higher concordance rate among identical twins compared with fraternal twins. For instance, the rate in multiple sclerosis is 35% in identical twins compared to 6% in fraternal twins.

Balancing infection and autoimmunity
There's increasing evidence that certain genes selected during evolution offer a balance between susceptibility to infection and our capacity to avoid autoimmune diseases. For example, variants in the ERAP2 gene provide some resistance to infection even though they increase the risk of autoimmunity (positive selection). In contrast, variants in the TYK2 gene protect against autoimmune diseases but increase the risk of infection (negative selection). This suggests the benefits of infection resistance may outweigh the risks of autoimmune diseases, particularly given the historically high risk of infection.

Several experimental methods such as the genome-wide association studies (GWAS) have been used to identify genetic risk variants that may be responsible for diseases such as Type 1 diabetes and Rheumatoid arthritis.

Similarly, in twin studies, autoimmune diseases consistently demonstrate a higher concordance rate among identical twins compared with fraternal twins, e.g. 35% vs. 6% in multiple sclerosis.

There is also increasing evidence that certain genes have been selected during evolution that provide a balance between our susceptibility to infection and our ability to avoid autoimmune diseases. For instance, variants in the ERAP2 gene provide some resistance to infection even though they increase the risk of autoimmunity (positive selection). By contrast, variants in the TYK2 gene protect against autoimmune diseases but increase infectious risk (negative selection). This suggests that the benefits of infection resistance outweigh the risk of autoimmune diseases, which is not surprising given the high risk of infection during most of human history.

Environmental factors
A significant number of environmental factors have been implicated in the development and progression of various autoimmune diseases, either directly or as catalysts. Current research suggests that up to seventy percent of autoimmune diseases could be attributed to environmental influences, which encompass an array of elements such as chemicals, infectious agents, dietary habits, and gut dysbiosis. However, a unifying theory that definitively explains the onset of autoimmune diseases remains elusive, emphasizing the complexity and multifaceted nature of these conditions.

Various environmental triggers are identified, some of which include:
 * Impaired oral tolerance
 * Gut dysbiosis
 * Increased gut permeability
 * Heightened immune reactivity

Chemicals, which are either a part of our immediate environment or found in drugs, are key players in this context. Examples of such chemicals include hydrazines, hair dyes, trichloroethylene, tartrazines, hazardous wastes, and industrial emissions.

Ultraviolet (UV) radiation has been implicated as a potential causative factor in the development of autoimmune diseases, such as dermatomyositis. Furthermore, exposure to pesticides has been linked with an increased risk of developing rheumatoid arthritis. Vitamin D, on the other hand, appears to play a protective role, particularly in older populations, by preventing immune dysfunctions.

Infectious agents are also being increasingly recognized for their role as T cell activators - a crucial step in triggering autoimmune diseases. The exact mechanisms by which they contribute to disease onset remain to be fully understood. For instance, certain autoimmune conditions like Guillain-Barre syndrome and rheumatic fever are thought to be triggered by infections. Furthermore, analysis of large-scale data has revealed a significant link between SARS-CoV-2 infection (the causative agent of COVID-19) and an increased risk of developing a wide range of new-onset autoimmune diseases.

Hormonal factors
Autoimmune diseases disproportionately affect women, suggesting a possible role for hormonal factors. For example, some autoimmune diseases tend to flare during pregnancy, when hormone levels are high, and improve after menopause, when hormone levels decrease. However, the precise role hormones play in the development of these conditions remains a subject of ongoing research.

Infections
Certain viral and bacterial infections have been linked to autoimmune diseases. For instance, research suggests that the bacterium that causes strep throat, Streptococcus pyogenes, might trigger rheumatic fever, an autoimmune response affecting the heart. Similarly, some studies propose a link between the Epstein-Barr virus, responsible for mononucleosis, and the subsequent development of multiple sclerosis or lupus.

Dysregulated immune response
Another area of interest is the immune system's ability to distinguish between self and non-self, a function that's compromised in autoimmune diseases. In healthy individuals, immune tolerance prevents the immune system from attacking the body's own cells. When this process fails, the immune system may produce antibodies against its own tissues, leading to an autoimmune response.

Negative selection and the role of the thymus
The elimination of self-reactive T cells occurs primarily through a mechanism known as "negative selection" within the thymus, an organ responsible for the maturation of T cells. This process serves as a key line of defense against autoimmunity. If these protective mechanisms fail, a pool of self-reactive cells can become functional within the immune system, contributing to the development of autoimmune diseases.

Molecular mimicry
Some infectious agents, like Campylobacter jejuni, bear antigens that resemble, but are not identical to, the body's self-molecules. This phenomenon, known as molecular mimicry, can lead to cross-reactivity, where the immune response to such infections inadvertently results in the production of antibodies that also react with self-antigens. An example of this is Guillain–Barré syndrome, in which antibodies generated in response to a C. jejuni infection also react with the gangliosides in the myelin sheath of peripheral nerve axons.

Diagnosis
Diagnosing autoimmune disorders can be complex due to the wide range of diseases within this category and their often overlapping symptoms. Accurate diagnosis is crucial for determining appropriate treatment strategies. Generally, the diagnostic process involves a combination of medical history evaluation, physical examination, laboratory tests, and, in some cases, imaging or biopsies.

Medical history and examination
The first step in diagnosing autoimmune disorders typically involves a thorough evaluation of the patient's medical history and a comprehensive physical examination. Clinicians often pay close attention to the patient's symptoms, family history of autoimmune diseases, and any exposure to environmental factors that might trigger an autoimmune response. The physical examination can reveal signs of inflammation or organ damage, which are common features of autoimmune disorders.

Laboratory tests
Laboratory testing plays a pivotal role in the diagnosis of autoimmune diseases. These tests can identify the presence of certain autoantibodies or other immune markers that indicate a self-directed immune response.


 * Autoantibody testing: Many autoimmune diseases are characterized by the presence of autoantibodies. Blood tests can identify these antibodies, which are directed against the body's own tissues. For example, antinuclear antibody (ANA) testing is commonly used in the diagnosis of systemic lupus erythematosus (SLE) and other autoimmune diseases.
 * Complete Blood Count (CBC): A CBC can provide valuable information about the number and characteristics of different blood cells, which can be affected in some autoimmune diseases.
 * C-Reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR): These tests measure the levels of inflammation in the body, which is often elevated in autoimmune disorders.
 * Organ-specific tests: Certain autoimmune diseases target specific organs, so tests to evaluate the function of these organs can aid in diagnosis. For example, thyroid function tests are used in diagnosing autoimmune thyroid disorders, while a biopsy can diagnose celiac disease by identifying damage to the small intestine.

Imaging studies
In some cases, imaging studies may be used to assess the extent of organ involvement and damage. For example, chest x-rays or CT scans can identify lung involvement in diseases like rheumatoid arthritis or systemic lupus erythematosus, while an MRI can reveal inflammation or damage in the brain and spinal cord in multiple sclerosis.

Differential diagnosis
Given the variety and nonspecific nature of symptoms that can be associated with autoimmune diseases, differential diagnosis—determining which of several diseases with similar symptoms is causing a patient's illness—is an important part of the diagnostic process. This often involves ruling out other potential causes of symptoms, such as infections, malignancies, or genetic disorders.

Multidisciplinary approach
Given the systemic nature of many autoimmune disorders, a multidisciplinary approach may be necessary for their diagnosis and management. This can involve rheumatologists, endocrinologists, gastroenterologists, neurologists, dermatologists, and other specialists, depending on the organs or systems affected by the disease.

In summary, the diagnosis of autoimmune disorders is a complex process that requires a thorough evaluation of clinical, laboratory, and imaging data. Due to the diverse nature of these diseases, an individualized approach, often involving multiple specialists, is crucial for an accurate diagnosis.

For a disease to be regard ed as an autoimmune disease it needs to answer to Witebsky's postulates (first formulated by Ernest Witebsky and colleagues in 1957 and modified in 1994):
 * Direct evidence from transfer of disease-causing antibody or disease-causing T lymphocyte white blood cells
 * Indirect evidence based on reproduction of the autoimmune disease in experimental animals
 * Circumstantial evidence from clinical clues

Symptoms of early autoimmune disease are often the exact same as common illnesses, including: fatigue, fever, malaise, joint pain, and rash. Due to the fact symptoms vary for affected location, disease causing agents, and individuals, it is difficult for proper diagnosis. Typically, diagnosis begins with looking into a patient's family's history for genetic predisposition. This is combined with various tests, as no single test can identify an autoimmune disease.

Antinuclear antibody
A test used to identify abnormal proteins, known as antinuclear antibodies, produced when the body attacks its own tissues. It may test positive in several disorders. This test is most useful for diagnosing systemic lupus erythematosus, having a 95% positive test rate.

Complete blood count
A test taking measurements on maturity levels, count, and size of blood cells. Targeted cells include: red blood cells, white blood cells, hemoglobin, hematocrit, and platelets. Based on increased or decreased numbers in these counts, underlying medical conditions may be present; typically, autoimmune disease is represented by low white blood cell count (Leukopenia). For proper diagnosis, further testing is needed.

Complement
A test used to measure levels of a protein group of the immune system called complement within blood. If complement is found in low levels, this may be an indication of disease.

C-reactive protein
C-reactive protein, a protein made in the liver, generally increases with inflammation, and may be high in autoimmune disease.

Erythrocyte sedimentation rate
This test measures the rate at which a patient's blood cells descend in a test tube. More rapid descents may indicate inflammation, a common symptom of autoimmune disease.

If these tests are indicative antibody abnormalities and inflammation, further tests will be conducted to identify the autoimmune disease present.

Treatment
The treatment of autoimmune diseases is tailored according to the type and severity of the condition. These diseases are typically chronic, and while they have no definitive cure, effective management strategies can alleviate and control symptoms. Treatment approaches can be classified into standard and emerging therapies.

Standard therapies
Standard or traditional treatment therapies aim to address the symptoms and counteract the adverse effects of the disease on the body. These methods include:


 * Supplementation: Administering supplements such as vitamins, hormones, or substances that the body lacks due to the disease. For instance, insulin for type 1 diabetes or thyroid hormone for hypothyroidism.
 * Blood transfusions: Required for some blood-related autoimmune conditions.
 * Physical therapy: This is recommended when the disease affects bones, joints, or muscles, helping to maintain mobility and function.
 * Immunosuppressive drug: These drugs are used to curb the immune system's attack on the body's own tissues. Examples include non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids, which reduce inflammation, and disease-modifying anti-rheumatic drugs (DMARDs), which lessen the damaging tissue and organ effects of the inflammatory autoimmune response.

While these therapies can relieve symptoms, they also weaken the immune response, potentially compromising the patient's ability to combat infections. Therefore, a balance must be struck between symptom relief and preserving the patient's immune defenses.

Emerging therapies
When traditional treatments are inadequate, emerging therapies are considered. These methods aim to be more precise and less toxic, focusing on blocking the activation of pathogenic cells or altering their suppression pathway.

Monoclonal antibodies
Monoclonal antibodies (mAb) are emerging as potent therapies for autoimmune diseases due to their ability to target specific cellular receptors or signaling molecules with high precision. These laboratory-produced molecules mimic the antibodies that the body naturally produces as part of the immune system's defense against pathogens. In the context of autoimmune diseases, they are designed to either block inflammatory signals or to specifically target and neutralize the rogue immune cells causing disease.

Infliximab and adalimumab are monoclonal antibodies designed to inhibit tumor necrosis factor alpha (TNF-α), a protein involved in systemic inflammation. By binding to and neutralizing TNF-α, these mAbs prevent it from exerting its pro-inflammatory effects. These drugs have shown effectiveness in treating diseases characterized by excessive inflammation such as rheumatoid arthritis, Crohn's disease, ulcerative colitis, and ankylosing spondylitis.

Basiliximab and daclizumab operate differently by targeting interleukin-2 (IL-2), a protein that promotes the growth and differentiation of T cells, which are central to the immune response. These mAbs inhibit the action of IL-2 on activated T cells, reducing the immune response that leads to tissue damage in autoimmune diseases. They are particularly useful in preventing the acute rejection of kidney transplants, a process largely driven by an aggressive immune response.

Omalizumab is a monoclonal antibody that inhibits human immunoglobulin E (IgE), a class of antibodies that play a critical role in allergic reactions. By neutralizing IgE, omalizumab can prevent the release of histamine and other inflammatory substances from mast cells and basophils, thereby reducing inflammation and allergic reactions. This mAb has proven effective in treating moderate-to-severe allergic asthma and autoimmune urticaria.

Co-stimulatory Blockade: This therapy prevents the pathway leading to an autoimmune response.

Regulatory T Cell Therapy: This treatment uses a specific type of T cell to suppress the autoimmune response.

Emerging therapies are being researched, developed, and used, especially when traditional treatments fail. These methods aim to either block the activation of pathogenic cells in the body, or alter the pathway that suppresses these cells naturally. These treatments aim to be less toxic to the patient and have more specific targets. Such options include:
 * Monoclonal antibodies that can be used to block pro-inflammatory cytokines
 * Antigen-specific immunotherapy which allows immune cells to specifically target the abnormal cells that cause autoimmune disease
 * Co-stimulatory blockade that works to block the pathway that leads to the autoimmune response
 * Regulatory T cell therapy that utilizes this special type of T cell to suppress the autoimmune response
 * Thymoquinone, a compound found the flower Nigella sativa, has been studied for potential in treating several autoimmune diseases due to its effects on inflammation.

Epidemiology
The first estimate of US prevalence for autoimmune diseases as a group was published in 1997 by Jacobson, et al. They reported US prevalence to be around 9 million, applying prevalence estimates for 24 diseases to a US population of 279 million. Jacobson's work was updated by Hayter & Cook in 2012. This study used Witebsky's postulates, as revised by Rose & Bona, to extend the list to 81 diseases and estimated overall cumulative US prevalence for the 81 autoimmune diseases at 5.0%, with 3.0% for males and 7.1% for females. The estimated community prevalence, which takes into account the observation that many people have more than one autoimmune disease, was 4.5% overall, with 2.7% for males and 6.4% for females. National Health and Nutrition Examination Surveys conducted in the US from the 1980s to present day, have shown an increase of antinuclear antibodies, a common biomarker for autoimmune diseases. This shows that there has been an increase in the prevalence of autoimmune diseases in recent years pointing to a stronger influence of environment factors as a risk factor for autoimmune diseases.

Prevalence
Prevalence of some common autoimmune diseases, which varies geographically, is listed below.

Research
Autoimmune and inflammatory diseases both originate from abnormal responses of the human adaptive or innate immune systems. In autoimmune diseases, the immune system targets the body's own proteins, while in chronic inflammatory diseases, leukocytes such as neutrophils are consistently recruited by cytokines and chemokines, leading to tissue damage. Mitigating inflammation through activation of anti-inflammatory genes and the suppression of inflammatory genes in immune cells is a promising therapeutic approach under active investigation. Additionally, research indicates that once autoantibodies, which are antibodies that target the body's own cells, have been activated, they may have the capacity to sustain their own production.

Research suggests an overall correlation between autoimmune diseases and cancer, in that having an autoimmune disease increases the risk of developing certain cancers. Autoimmune diseases cause inflammation in various ways, but the particular cause of inflammation does not greatly affect cancer risk. Rather, the cancer risk depends largely on the fact that all autoimmune diseases increase chronic inflammation, which has been linked to cancer. Below are some autoimmune diseases most commonly linked to cancer, including celiac disease, inflammatory bowel disease (Crohn's disease and ulcerative colitis), multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus.

In both autoimmune and inflammatory diseases, the condition arises through aberrant reactions of the human adaptive or innate immune systems. In autoimmunity, the patient's immune system is activated against the body's own proteins. In chronic inflammatory diseases, neutrophils and other leukocytes are constitutively recruited by cytokines and chemokines, resulting in tissue damage.

Mitigation of inflammation by activation of anti-inflammatory genes and the suppression of inflammatory genes in immune cells is a promising therapeutic approach. There is a body of evidence that once the production of autoantibodies has been initialized, autoantibodies have the capacity to maintain their own production.

Stem-cell therapy
Stem cell transplantation is being studied and has shown promising results in certain cases.

Medical trials to replace the pancreatic β cells that are destroyed in type 1 diabetes are in progress.

Altered glycan theory
According to this theory, the effector function of the immune response is mediated by the glycans (polysaccharides) displayed by the cells and humoral components of the immune system. Individuals with autoimmunity have alterations in their glycosylation profile such that a proinflammatory immune response is favored. It is further hypothesized that individual autoimmune diseases will have unique glycan signatures.

Hygiene hypothesis
According to the hygiene hypothesis, high levels of cleanliness expose children to fewer antigens than in the past, causing their immune systems to become overactive and more likely to misidentify own tissues as foreign, resulting in autoimmune or allergic conditions such as asthma.

Vitamin D influence on immune response
Vitamin D is known as an immune regulator that assists in the adaptive and innate immune response. A deficiency in vitamin D, from hereditary or environmental influence, can lead to a more inefficient and weaker immune response and seen as a contributing factor to the development of autoimmune diseases. With vitamin D present, vitamin D response elements (VDRE) are encoded and expressed via pattern recognition receptors (PRR) responses and the genes associated with those responses. The specific DNA target sequence expressed is known as 1,25-(OH)2D3. The expression of 1,25-(OH)2D3 can be induced by macrophages, dendritic cells, T-cells, and B-cells. In the presence of 1,25-(OH)2D3, the immune system's production of inflammatory cytokines are suppressed and more tolerogenic regulatory T-cells are expressed. This is due to vitamin D's influence on cell maturation, specifically T-cells, and their phenotype expression. Lack of 1,25-(OH)2D3 expression can lead to less tolerant regulatory T-cells, larger presentation of antigens to less tolerant T-cells, and increased inflammatory response.