Applied Blood And Immunity Flashcards
What can go wrong with the immune system
When your immune system doesn’t work the way it should, it is called an immune disorder
1) you could be born with a weak immune system. This is called primary immune deficiency
2) you could get a disease (or medication) that weakens your immune system. This is called acquired immune deficiency
3) you could have an immune system that is too active. This may happen with an allergic reaction (anaphylaxis)
4) you could have an immune system that turns against you. This is called autoimmune disease e.g. lupus, rheumatoid arthritis
Severe combined immunodeficiency (SCID)
- rare genetic disorder characterised by the disturbed development of functional T cells and B cells (caused by numerous genetic mutations)
- SCID involves defective antibody response due to either direct involvement with B lymphocytes or through improper B lymphocyte activation due to non-functional T helper cells
- thus the B cells and T cells of the adaptive immune system are impaired due to a defect in one if several possible genes
- SCID is one of the most severe form of primary immune deficiencies
- there are now at least 9 different known genes in which mutations lead to a form of SCID
Diagnosing SCID
- diagnosed in early infancy
- babies with SCID may seem well at birth and for the first few weeks of life as they are partially protected by mothers antibodies
- the first signs of SCID usually occur within the first 3-6 months of
- parents may seek help from their GP or A&E because if repeated infections, poor weight gain or feeding problems
- SCID may be suspected, usually because of low lymphocyte count in the blood
Treating SCID
- immunoglobulin replacement therapy (acquired from a pool of live donors)
- blood, platelet or plasma transfusions
- the most effective treatment is bone marrow transplant (stem cell transplant). Main treatment for SCID babies
- it involves receiving healthy stem cells from a matched donor, usually a healthy sibling
- the new cells then rebuild the immune system of an infant with SCID
- it is possible for children who receive this type of transplant to be cured
Temporary acquired immune deficiencies
- immune system can be weakened by certain medicines
- for example: chemotherapy or other drugs used to treat cancer, following organ transplants (immunosuppressants to prevent organ rejection)
- infections like the flu virus and measles can weaken the immune system for a brief time
- your immune system can also be weakened by smoking, alcohol and poor nutrition
HIV and AIDS
- HIV (human immunodeficiency virus) is a virus that attacks the body’s immune system
- if not treated, it can lead to AIDS (acquired immunodeficiency syndrome)
HIV symptoms
- some people have flu like symptoms within 2-4 weeks after infection (called acute HIV infection)
- these symptoms must last for a few days or several weeks
- HIV attacks and destroys CD4 cells (T cells). A CD4 count is used to check the health of the immune system in infected people
The stages of HIV
- without treatment the patient will progress through these stages
- the three stages are: acute, chronic, AIDS
- HIV medicine can slow or prevent progression of the disease
- with the advancements in treatment progression to stage 3 is less common today than in the early days of HIV
HIV treatment
- HIV treatment is called antiretroviral therapy (ART)
- ART involves taking a combination of HIV medicines
- the aim of HIV treatment is to reduce a persons viral load to an undetectable level
- treatment is initiated with a combination of two nucleoside reverse transcriptase inhibitors (NRTIs) plus either an integrate inhibitor (INI), a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a boosted protease inhibitor (PI)
- people with HIV who maintain an undetectable viral load have effectively no risk of transmitting HIV to their HIV negative partners through sex
An overactive immune system
- genetic origin
- immune system may react to substances (allergens) in the environment that are normally harmless
- having an allergic reaction is the most common example of an overactive immune system
E.g. asthma, eczema, allergic rhinitis
Autoimmune diseases
3 common types of autoimmune diseases are:
1) type 1 diabetes»_space;> the immune system attacks the cells in pancreas which make insulin. Insulin removes sugar from the blood to use as energy
2) rheumatoid arthritis»_space;> this type of arthritis causes swelling and deformities of the joints. An auto-antibody called rheumatoid factor is in the blood of some people with rheumatoid arthritis
3) lupus»_space;> this disease that attacks body tissues, including the lungs, kidneys and skin. Many types of auto-antibodies are found in the blood of people
Rheumatoid arthritis
- a long term condition that causes pain, swelling and stiffness in the joints. The condition usually affects the hands, feet and wrists
- there may be periods symptoms become worse, known as flare ups
- a flare up can be difficult to predict but with treatment its possible to decrease the number of flares and minimise or prevent long term damage to the joints
Symptoms of rheumatoid arthritis
- joint pain
- stiffness
- the lining of the joints affected by rheumatoid arthritis become inflamed, which can cause the joints to swell and become hot and tender to touch
Rheumatoid arthritis treatment
- treatment aimed at reducing inflammation in the joints, relieve pain, prevent and slow down joint damage
- there is no cure for rheumatoid arthritis
- disease-modifying anti-rheumatic drugs (DMARDs) e.g. methotrexate
- methotrexate is first line for rheumatoid arthritis, often with another DMARD and a short course of steroids (corticosteroids) to relieve any pain
Blood disorders
- often result in inability to clot or tendency to clot too much
- can be genetic but can also develop as a result of other diseases, medications or a lack of nutrients in the diet
- some resolve completely with therapy, or do not cause symptoms and are benign
- some are chronic and lifelong but do not affect how long you live
- others like sickle cell disease and blood cancers can be fatal
- e.g. anaemia, haemophilia, leucocytosis, polycythaemia Vera, thalassaemia, Von willebrand disease
