Autoimmunity Flashcards
(11 cards)
What is autoimmunity?
In autoimmune conditions the immune system incorrectly reacts to the body’s own tissues – inappropriate and persistent immune response of the body against its own tissues.
Autoimmunity may be an antibody response (autoantibodies) or a cellmediated response.
Autoimmunity may be organ specific (e.g. thyroid –Graves disease) or nonorgan specific/systemic (e.g. rheumatoid disease)
- Approximately 6% of the UK population has an autoimmune disease
- There is a prevalence of females to males in many autoimmune conditions, but there is relatively equal incidence in some conditions such as diabetes.
The study of autoimmunity involves a lot of terminology, so a quick reminder of key words and their definitions is handy:
Antigen – ‘any substance (such as an immunogen or a hapten) foreign to the body that evokes an immune response either alone or after forming a complex with a larger molecule (such as a protein) and that is capable of binding with a product (such as an antibody or T cell) of the immune response’
Antibody – ‘any of a large number of proteins of high molecular weight that are produced
normally by specialized B cells after stimulation by an antigen and act specifically against the
antigen in an immune response, that are produced abnormally by some cancer cells, and that typically consist of four subunits including two heavy chains and two light chains— called also immunoglobulin’
Enzyme – ‘any of numerous complex proteins that are produced by living cells and catalyse
specific biochemical reactions at body temperatures’ (all definitions sourced from the Merriam Webster dictionary)”
How does autoimmunity develop?
In a healthy individual, tolerance to self begins with recognition and deletion of self-reactive B
and T cells during their maturation phase in the thymus and bone marrow.
Inhibition of the expansion of autoreactive cells by regulatory T cells, and the need for (and absence of) certain costimulatory signals to activate these autoreactive cells usually ensures the continuation of self-tolerance. This is benign autoimmunity.
In susceptible individuals under certain conditions these self-reactive cells are no
longer inhibited and thus pathogenic autoimmunity develops.
Autoimmune disease is not caused by a single micro-organism or gene; it is an interplay of
factors which build to a ‘tipping point’.
HLA stands for human leukocyte antigen – this is a complex of genes which encode some of the cell proteins responsible for regulating the immune system
What blood markers can impact on autoimmunity?
It is useful to consider an overview of the blood markers that may be present in a patients test
results when looking for potential autoimmunity. These markers fall into two categories – specific and non-specific
Both holistic and biomedical health professionals will often use blood tests to confirm or rule out a potential condition.
For some conditions this is a clear yes/no process, with a specific finding in the blood allowing for definitive diagnosis (for example venous plasma glucose of more than 11.1 mmol/l is defined as diagnostic of diabetes).
Autoimmune disease does not easily fit the positive/negative test result model, requiring more nuanced detective work in our clinical investigations. Thinking back to the presence of HLA (human leukocyte antigen) as a susceptibility marker illustrates this – many healthy individuals will have these susceptibility markers while some autoimmune patients won’t have them.
It is essential to retain a critical view of blood test results, and ensure they are viewed in the
context of all patient information. In order to arrive at a working diagnosis of rheumatoid
arthritis, for example, a clinician would require more than the presence of rheumatoid factor in the blood. Case history, blood results and clinical presentation are an interdependent trio of information which should always be considered together.
What role does inflammation have in autoimmunity?
Thinking back to our lesson on infection, we considered how infection causes inflammation,
which allows infection to persist causing further inflammation:
The persistence of inflammation does not just
provide ideal conditions for chronic infection – it could also be seen as a driver of the autoimmune response.
Remember the danger model of immunity? This allows us to view the constant and abnormally damaged tissue of chronic inflammation as the ‘danger’ signal that triggers an abnormal immune response. The simplistic view of autoimmunity as the body’s defence systems turning on it’s own
tissues now has more nuance – it is an immune response to damage”
Why is diet and microbiome critical to managing autoimmune disease?
“Beneficial diet and good digestive health are fundamental to improving the outlook in cases of autoimmune disease. A healthy microbiome has a large role to play in defence against colonisation by pathogens:
1. It provides a barrier effect through the massive numbers of ‘good’ microorganisms
2. Antimicrobial substances are produced to neutralise pathogens
3. It ‘trains’ the early immune system to respond to a broad range of threats
If the microbiome is disordered (a state of dysbiosis) then persistence of pathogens, particularly in the bowel, is more likely.
Persistence of pathogens sets up the state of chronic inflammation that we considered in lesson 1, permitting inappropriate colonisation of the bowel and potential passage of pathogenic and antigenic materials into and across an inflamed and compromised
gut wall
Some elements eaten are linked to the development of autoimmunity. Lectin proteins in the diet and autoimmunity
Lectin – any of a group of proteins especially of plants that are not antibodies and do not
originate in an immune system but bind specifically to carbohydrate-containing receptors on cell surfaces (as of red blood cells) - this causes agglutination, a clumping together of carbohydrate molecules. Legumes, beans, nightshades and peanuts are among the huge variety of foods containing lectins – they are found in nearly all fruits and vegetables, with wheat, soybean, kidney bean and peanut being those proposed to cause most reactivity. Gluten is the most commonly recognised lectin protein to caused recognised reactivity
Bringing together the factors we have looked at so far, we can see that poor digestive health could easily act as a trigger for autoimmune disease. The factors we looked at in this lesson included:
* Gastrointestinal inflammation
* Poor hepatic screening of blood from the digestive system
* Gut dysbiosis
* Hyperpermeability of the GIT wall
We can add to this the factors looked at in previous lessons which predispose
to autoimmune disease:
* Genetic predisposition
* Stress
* Environmental and lifestyle factors
What impact might gut hyperpermeability have?
“Kerry Bone’s paper ‘A Phytotherapeutic Approach to Autoimmune Disease’ (1995) outlines the concept of hyperpermeability of the intestinal wall.
Essentially, the anatomy and physiology of the gut must strike the balance between providing a barrier against pathogens, while allowing fluid and essential nutrients across.
Inappropriate diet, poor gut circulation, infection and other factors may disrupt the balance of the barrier potentially increasing
permeability and so the potential for increased antigenic load outside the gut
How important is digestive health in pre-existing autoimmune conditions?
Whether a patient has been experiencing autoimmune disease for a week or a decade, addressing digestive function is always necessary.
Imagine putting a dressing on a leg ulcer, only for someone else to come along
every day, lift the dressing and put dirt into the wound – it would not heal, and nor can improvement in autoimmune conditions be achieved if an inflamed gut is hosting the very pathogens or allowing passage of
the key antigens that may have triggered the autoimmune condition in the first place.
The protocol set forward in Kerry Bone’s paper, mentioned earlier, not only gives an excellent starting point for treatment but provides a really useful breakdown of where gut issues sit in the overall autoimmune picture. As such, it is worth seeking it out and perhaps developing on its framework with your own understanding of autoimmunity and gut health.”
Common autoimmune diseases - Psorisis and RA
Psoriasis
Signs and symptoms:
* Red raised plaques with thick white/silver scaly surface on knees, elbows, trunk and scalp, nails and less often skin flexures
* May be guttate in children and teens (teardrop shaped lesions) and rarely pustular (if generalised, it is serious and causes fever, localised occurs on palms and soles)
Rheumatoid arthritis
Signs and symptoms:
* Symmetrical inflammation starting in fingers and progressing through toe and ankle joints, knees, shoulders and hips
* Joint pain, stiffness, symmetrical swelling
* Rheumatoid factor may be present in blood test results
Common autoimmune diseases - diabetes, Crohn’s & ulcerative colitis
Type 1 diabetes – insulin dependent
Signs and symptoms:
* Thirst (polydipsia)
* Polyuria and nocturia
* Rapid significant weight loss (ensure malignancy ruled out if encountered in clinic)
* If ketoacidosis develops, deep sighing breathing and a sickly sweet smell to the breath may occur
Inflammatory bowel disease –
Crohn’s disease and ulcerative colitis
Signs and symptoms:
UC – rectal bleeding, mucous discharge, tenesmus, diarrhoea or constipation, blood in stool, potential for weight loss, malaise, fever and abdominal pain
* Crohn’s – abdominal pain causing weight loss
through aversion to eating, weight loss through
malabsorption, blood in stool if colon site of
inflammation, otherwise watery diarrhoea
Common autoimmune diseases - MS, Hashimoto’s and Grave’s Disease
Multiple sclerosis
Signs and symptoms:
* Remitting relapsing subacute pattern
* Optic neuritis
* Spine and limb tingling when flexing neck
* Sensory symptoms
* Loss of upper limb function (gradual)
* Postural tremor
* Facial palsy
* Trigeminal neuralgia in patients under 50
Hashimoto’s thyroiditis –hypothyroid presentation
Signs and symptoms:
* Goitre (swollen thyroid) * Tiredness
* Weight gain
* Cold intolerance
* Hoarse voice
* Bradycardia and hypertension
* May present with attendant depression or may be misdiagnosed with depression
Grave’s disease- hyperthyroid
Signs and symptoms:
* Goitre
* Exophthalmos (protuberant staring eyes)
* Weight loss
* Heat intolerance
* Palpitations and rapid heart rate, possible atrial fibrillation
* Diarrhoea
* Anxiety and restlessness presentation
Common autoimmunne diseases - Sarcoidosis, Pernicious anaemia and Myasthenia gravis
Sarcoidosis
Signs and symptoms: * Fatigue
* Swollen lymph nodes
* Weight loss
* Pain and swelling in joints
* Cough, shortness of breath, wheezing, chest pain* Blurred vision, eye pain
* Reddish purple bumpy rash on shins/ankles
Pernicious anaemia
Signs and symptoms:
* Fatigue
* Pallor
* Shortness of breath
* Dizziness
* Paraesthesia (peripheral numbness and tingling)
* Muscle weakness
* Irregular heartbeat
Myasthenia gravis
Signs and symptoms:
* Muscle weakness
* Drooping eyelids (ptosis)
* Double vision (diplopia)
* Difficulty swallowing
* Impairment of speech and facial expression
