Globally, it is estimated that 5-10% of the population has at least one autoimmune disease – and it’s further thought that approximately 75% of sufferers are women. Medical researcher and female health advocate, Dr. Emily Handley asks why.
Autoimmune diseases conditions attack your immune system, causing ‘friendly fire’: where your own body mistakes normal cells and tissues for invaders and begins to attack itself. So how can we reduce our risk of developing these diseases? And why are women disproportionately impacted.
What is our immune system?
The immune system is a complex network of processes in our body that protects us from disease. It acts to detect and react to pathogens – invaders such as cancer cells, toxins and foreign objects like splinters. We are born with our innate immune system which works to respond in a predetermined way to situations and pathogens.
This includes physical barriers like our skin, or fluids such as the mucus found in our lungs and digestive tract. Our adaptive immune system on the other hand develops over time and with different exposures. It is reaction-specific, and tailored to each situation it encounters, learning to recognise new circumstances.
The components of our body that create the cells of our immune systems include:
- Bone marrow: a primary part of the system. All the body’s blood cells originate in bone marrow.
- Peyer’s patches: found in the lowest part of the small intestine. Acts as an immune surveillance system in the gut, trapping foreign particles and destroying them.
- Tonsils: Similar to Peyer’s patches. The tonsils prevent foreign particles slipping into the lungs, detecting, surveilling and destroying those that may be harmful.
- Thymus: located behind sternum, between the lungs. The thymus is only active until puberty. Produces and mature T-cells, critical for battling virus and infection.
- Adenoids: the adenoids are inside the nose, towards the back of the head. Like the tonsils and Peyer’s patches, the organ protects the upper respiratory tract from foreign pathogens – particularly in young children.
- Spleen: a small organ just above and to the left of the stomach. The spleen makes white blood cells and detects faulty red bloods cells, as well as unwelcome foreign particles.
- Lymph: lymphatic fluid is the extra fluid that drains from tissue and cells. It also includes minerals, fats, damaged cells, nutrients, bacteria and viruses. Importantly, lymph also transports white blood cells.
- Lymph nodes: small glands (or nodes) that span the body, within which immune cells cluster and stand ready to fight foreign substances.
- Lymphatic vessels: a network of vessels and capillaries throughout the body that collect, filter and move lymph at nodes towards larger vessels.
- White blood cells: the major players of the immune system, these cells are made in bone marrow and then become part of the lymphatic system. White blood cell search for foreign particles and then launch immune attacks.
- Antibodies: fighting microbes or toxins, antibodies identify antigens on the surface of foreign invaders, marking them as dangerous. This marks them for destruction.
- Complement system: finally, a system made up of proteins whose functions are complementary to the role of antibodies;
The main tasks of this complex system are fighting disease-causing foreign invaders; recognising harmful substances; and fighting disease-causing changes in the body.
What are autoimmune diseases?
Having an over-active or under-active immune system is relatively common. Examples of an under active immune system are grouped under ‘immunodeficiency disorders’ and can be inherited, or arise due to medical treatments like chemotherapy. An under active immune system can also be triggered by other diseases, such as HIV/AIDS. The overactivity of the immune system can be induced by allergic diseases – where the system mounts an overly-strong attack on allergens – and autoimmune diseases.
Autoimmune diseases occur when our immune system goes haywire. The system mounts a response against the normal parts of our body, resulting in at least 80 different types of disease that can range from being a common occurrence to incredibly rare. Multiple sclerosis is one of the more well-known diseases of an overactive immune system. The body attacks our neurons – or nerve cells – causing weakness, muscle spasms, pain and poor coordination. The first signs of multiple sclerosis are often loss of vision, or even loss of power in a limb. Psoriasis is a common form of autoimmune disease where certain immune system cells collect in the skin; this results in the overstimulation of skin cells and scaly, painful plaques. Inflammatory bowel disease (IBD) is a condition where the lining of the intestines is attacked by the immune system, causing fever, weight loss, diarrhoea, bleeding and abdominal pain. Two well-known forms of IBD are Crohn’s disease and ulcerative colitis. The immune system can even attack our joints, with rheumatoid arthritis occurring when antibodies are attached to the lining of joints. This results in swelling, pain, inflammation and eventual joint damage, impinging movement. Even type 1 diabetes mellitus is a disorder of the immune system, where antibodies attack the cells producing insulin in the pancreas.
Basically, when the immune system becomes overactive, there is not a single component of our body that cannot be targeted. But what makes a person more susceptible to an immune system gone AWOL?
Risk factors of autoimmune disease
While each type of autoimmune disease is unique and progresses through different pathways, all come back to an immune system in disarray. Genetics is one factor that we know has a large role in the progression of these diseases, as many run in families and can be inherited. Additionally, these diseases can affect specific ethnic or national populations, and specific genetic mutations are common in those with autoimmune disease. An example is that of multiple sclerosis; if a child has the inherited gene HLA-DRB1, the chance of developing the disease increases 20-fold. Even more intriguingly, there is evidence that a specific shared chromosome can predispose families to general autoimmunity; where one familial line may have an increased incidences of thyroid disorders, lupus, psoriasis and diabetes.
While scientists and specialists have increasingly greater insight as to how genetics can cause autoimmune disease, how our environment and lifestyle contribute to the triggers is still a puzzle. Even so, it’s currently though that as many as 70% of autoimmune diseases may arise from factors in the environment – though this still remains up for debate. Broadly, autoimmune diseases arising from the environment may be triggered by toxins including cigarettes; dietary factors, such as excessive salt; and infections, like the Epstein-Barr virus. The latter has been increasingly linked to rheumatoid arthritis, which may be due to antibodies mistakenly targeting the joint tissue instead of the virus due to similarities between proteins. Smoking is linked to multiple sclerosis and thyroid disorders, while salt can greatly alter our gut microbiota (discussed in greater detail here). This disrupted gut environment can increase the risk of type 1 diabetes, multiple sclerosis and obesity; in itself, a risk factor for arthritis.
Surprisingly, your age also dictates your risk of developing an autoimmune disease – but it’s not due to getting older. Most autoimmune diseases affect younger and middle-aged people, leaving people with a lifetime of disease management. But the most prevailing risk factor for autoimmune disease? Your sex: 75% of autoimmune diseases strike women.
Why are women more susceptible to autoimmune disease?
Multiple sclerosis affects women more than men at a ratio of 3:1, and in some diseases, women are 16-fold more susceptible. Sex hormones are the initial explanation targeted by researchers for discrepancy. Hormones regulate both our innate and adaptive immune systems, with receptors for the hormones (think of a lock and key) found on the surface of immune cells. This may help explain why the symptoms of autoimmune diseases can worsen or improve with changes in hormone levels. Women with multiple sclerosis experience a drastic reduction in their symptoms at the second half of pregnancy – when estrogen is ramping up its levels. But it is still unclear what effects in particular hormones may be having, and whether they are wholly positive, negative, or a combination of both.
Sex differences in autoimmune disease may also be associated with our sex chromosomes. Researchers have found that in animal models with two X chromosomes the development of lupus is increased more so than those with XY chromosomes. Amazingly, this is even when all animals still have the same reproductive organs and sex hormones. Scientists think this could be due to genes on X chromosomes with roles in immune system function, with multiple copies and overactivation of these gens potentially ramping up the immune response. Most likely, sex chromosomes exert their effects on the immune system through a complex interplay with our hormones and our environment, with the latter factors ‘unmasking’ the impact of chromosomes.
Others speculate that women simply have more complex immune systems as adaptive mechanisms to protect fetuses during pregnancy. This may also result in stronger responses to inflammation, a key factor of autoimmune disease. Age and sex work together when women hit the major hormonal changes of puberty, pregnancy and menopause to increase inflammatory and immune responses. The influx of sex hormones during these periods seems to be an invitation of sorts for autoimmune disease, with increased rates of onset during these times.
How can autoimmune diseases be treated and managed?
You can reduce your everyday risk of autoimmune disease with simple lifestyle changes. Washing your hands is one of the easiest ways to mitigate your risk, taking steps to reduce exposure to bacteria. And with increasing links between previous infections and autoimmune disease development, it’s important to avoid people who are sick and to stay up to date with your vaccinations.
Unfortunately, there are no treatments that can cure autoimmune disease; yet there are treatment plans available that can reduce symptoms and severity of flare-ups. These treatments act to:
- Control symptoms – over-the-counter drugs can provide relief from symptoms and pain. Prescription drugs and creams can also be used for symptoms, as well as subsequent depression, fatigue, anxiety and sleep issues.
- Maintaining vital substances – auto immune disease can deplete the essential substances of our body’s. Outside sources of hormone treatments or insulin are vital for certain conditions, as are supplements such as collagen.
- Immune system repression – while these disorders can’t be reversed, they can be slowed or halted. Some drugs can control progression, preserving the function of the parts of the body under attack.
- Increase movement: these disorders often reduce a person’s mobility. Physical therapy, in conjunction with therapeutic symptom relief, can improve movement and ease pain.
- Surgically intervene: in some cases, surgery is required to remove the dysfunctional tissue or organ, or to remove a secondary growth caused by the disorder. For example, removing bowel blockages in IBD, or the thyroid in severe thyroid disorders.
Being diagnosed with an autoimmune disease can be frightening; but early diagnosis is your best chance for managing the condition. Finding the right treatment plan that suits your lifestyle and mitigates symptoms is key to minimising the impact these disorders may have on someone’s life. Remember, symptoms of autoimmune diseases are non-specific; they often don’t follow a set series of events, and can simply initially be increased fatigue. The best source of prevention? Regular check-ups with your doctor to monitor any new symptoms or continuing issues. With the right treatment plan and early diagnosis, an autoimmune disease does not have to control your life.
This article provides general information only, and does not constitute health or medical advice. If you have any concerns regarding your health, seek immediate medical attention.