11 - IMMUNE SYSTEM PATHOLOGY Flashcards

1
Q

Pathologies of immune system

A

Hypersensitivity reactions
Autoimmune disorders
Immunodeficiencies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

DESCRIPTION: antigen

A

substance triggering immune reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Description: antibodies

A

specific binding to antigen facilitate phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Descripton: B cells

A

produces antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Function macrophages

A

Phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Description of cytotoxic T cells (CD8)

A

immune cell destroying infected cells (viruses) & cancer cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Description: Helper T cells CD4

A

boost activity of B cells & macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Description: Dendritic cells

A

antigen presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

fct neutrophils

A

kill bacteria, do phagocytosis & degranulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Description complement system

A

set of plasma protein: inflammation, kill cells, facilitate phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Description mast cells

A

release histamine, trigger inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Definition of hypersensitivity

A

disproportionate reactivity to antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Definition of hypersensitivity reactions

A

immune responses to harmless antigens causing symptoms upon re-exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Definition of hypersensitivity disease

A

persistent & recurrent reaction to innocuous antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Type 1 HS: features

A

Mediated by Ig E antibodies triggering mast cells
Immediate hypersensitivity: response within minutes

Many allergic reactions: reaction to common environmental allergens
Harmless substances that can be:
- Inhaled: pollen, dust misters
- Injected: venom from bees or wasps
- Contact allergies: metals, latex
- Eaten: nuts, shellfish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

type 1 HS: 2 steps reactions

A

1) First exposure = sensitization
Dendritic cell bring allergen to lymph nodes & show it to T helper cells
IL-4: stimulate B cells to produce antibodies (IgE)
IgE antibodies binds to mast cells (airways, GI tract, dermis)

2) Subsequent exposure
Allergen bind to mast cells: degranulation
* Release of pro-inflammatory mediators (histamine)
* Bronchospasm
* Vasodilation & increase permeability

17
Q

Type 1 hs: symptoms (mild & other)

A

Mild symptoms
Urticaria
Asthma
Eczema
Allergic rhinitis: most common 10-30% of population globally

Other symptoms
Runny or stuffy nose
Sneezing
Red, itchy & watery eyes
Swelling around eyes

18
Q

Anaphylaxis: type of HS, def & causes

A

Type 1

Definition
= life-threatening emergency & requires immediate intervention with injected epinephrine to restore blood pressure, strengthen heartbeat & open airways

Exposure to large quantity of allergen
Wide spread release of histamine: increase vasodilation + airways constriction
Not enough oxygen to vital organs

Causes
Insect bites & stings (ants, bees)
Food ingestion (peanuts, seafood)
Medication (penicillin, aspirin)

19
Q

Type 1 HS: treatment

A

Anti-histamines: counteract histamine effects
Corticosteroids: reduce inflammation
Epinephrine: induces vasoconstriction (prevent anaphylactic shock)

20
Q

Type 2 HS: 2 types

A

Cytotoxic hypersensitivity
Myasthenia gravis

21
Q

Cytotoxic hypersensitivity type 2 : def, features & steps

A

Definition
= antibody mediated destruction of healthy cells

Features
IgG antibodies recognize cell surface or matrix antigens
Tissue specific
Timing: 2-24h

Steps
1) Phagocytosis

2) Activation of complement system
- Recruitment of neutrophils & degranulation
- Lytic death of host cells

3) Cellular dysfunction

22
Q

Myasthenia gravis: type of HS, def, symptoms & def of myasthenia crisis

A

Type 2

Definition
= antibody directed against nicotinic receptors

Nerve impulse of motor neuron fail to pass neuromuscular junction & stimulate contraction
Fluctuating weakness & fatiguability of skeletal muscle (cranial muscles = first affected)
85% of patients generalized weakness affecting muscles of limbs (later onset)

= slow progressive disease with daily & longer term fluctuations in symptoms

Infections can lead to exacerbation of symptoms

Symptoms
Double vision & dropping eyelid
Fatigue while chewing
Open jaw
Difficulty swallowing
Trouble talking & walking

Myasthenia crisis
= life-threatening medical emergency due to weakening of respiratory muscles & requiring ventilatory assistance

23
Q

Type 3 HS: 2 types

A

Cytotoxic hypersensitivity
Systemic lupus erythematous

24
Q

Cytotoxic hypersensitivity type 3: def, features, An-Ab complex

A

Definition
= antibody mediated destruction of healthy cells

Features
IgG antibodies recognize soluble antigens
—> Formation of antigen-antibody complexes
Systemic
Timing: hours, days or even weeks

Antigen-antibody complexes
Less immunogenicity, difficult to trigger phagocytosis
Deposit on basal lamina of blood vessel

Activation of complement system
—> Inflammation: edema
—> Recruit neutrophils: degranulation & tissue damage

Results: vascular is
Most happening in skin, kidneys, joints, pleura & pericardium

25
Systemic lupus erythematous: type of HS & def
Type 3 = defects in apoptotic clearance can be associated with onset of SLE
26
Type 4 HS: description & name 1
T-cell mediated hypersensitivity: damage to tissue through CD4 or CD8 Delayed type hypersensitivity: 24-72h from exposure CD8+ mediated: directly kills target cells (perforin & granzymes) (Example: type I diabetes) CD4+ mediated: effector T helper cells activate macrophages —> Secrete pro-inflammatory cytokines that damage tissues Multiple sclerosis
27
Multiple sclerosis: def, symptoms, subtypes
Definition = primary T-cell mediated inflammatory disorder Inflammation Demyelination: neurons more susceptible to apoptosis (lesions) Irreversible axon loss & cell death (neurons & oligodendrocytes) Brain atrophy Symptoms Fatigue Pain Weakness & balance problems Sensory loss (paraesthesia or dysesthesia) Visual dysfunction (optic neuritis) Spasticity & spasms Coordination issues (ataxia) & tremors Depression Bladder & bowel symptoms Subtypes Clinically isolated syndrome Relapsing-remitting MS Secondary progressive MS Primary progressive MS
28
Autoimmune diseases: causes, treatment & etiology
Causes Loss of tolerance towards self-antigens Treatment Corticosteroids & NSAIDs to reduce inflammation & suppress immune reaction Physical therapy: if disease impacts bones, joints & muscles Etiology Often unknown Mix genetic predisposition, hormonal factors & environmental factors
29
Immunodeficiency diseases: types & leads to
Primary immunodeficiency: congenital conditions —> Mutation to genes affecting functioning of immune cells Secondary immunodeficiency: acquired —> Various factors reduce effectiveness of immune response in intrinsically normal immune system Immunodeficiency lead to Frequent & unusual complications of common infections (pneumonia) Opportunistic infections (Candida, CMV) Increase prevalence of tumors
30
Immunosuppressive drugs & adverse effects
Corticosteroids: to decrease inflammation —> One of the most common used drugs Adverse effects Related to dosage & chronic use => Present in 90% of patients after 60 days Osteoporosis & fracture: impairment of bone matrix mineralization Adrenal suppression: inadequate cortisol production Cushingoid features: weight gain & redistribution of adiposity Diabetes & hyperglycaemia: most common cause of drug induced diabetes Myopathy: muscle weakness & atrophy Glaucoma: increase in intraocular pressure Psychatric disturbances: psychosis, insomnia, euphoria, depression Immunosuppression: predispose patients to fungal & viral infections
31
Infectious disease: name one
HIV infection
32
% of infected people & routes of transmission of HIV
- 0,7% of population infected with HIV - Routes of transmission: unprotected sexual intercourse & sharing needles
33
HIV: life long infection: human immunodeficiency virus
Human immunodeficiency virus: 2 copies of ssRNA Capside Enzymes (retrotranscriptase, integrase) Envelope Envelope glycoprotein (gp120) HIV = retrovirus —> genome integrated in DNA of CD4 T-cells Infected T-cells will produce new HIV viruses
34
Killing CD4 T cell: cases of CD4 infected & non infected
CD4 helper cells infected by HIV can die: - Integrase cause DNA damage => apoptosis - Viral protease cleaves caspases => apoptosis - CD8 cytotoxic T cells recognize viral protein on surface => apoptosis - Antibodies recognizing viral protein on surface => apoptosis Building up of viral RNA => Pyroptosis: highly inflammatory cell death CD4 T helper cells not infected by HIV can also die: - Exposure to HIV: move to lymph nodes - Building up of viral RNA => pyroptosis: highly inflammatory cell death - Release of inflammatory cytokines - Death of non infected CD4 T cells through pyroptosis Chronic inflammation & disease progression
35
HIV: clinical manifestations: types & description of each
1) Acute infection - Initially high viral load - Production of antibodies (3-6 weeks) - Reduction of circulating virus Symptoms: Flu like symptoms Lymphoadenopathy 2) Latent period: asymptomatic HIV disease (CD4 count > 500 cells/mm3) - No clinical symptoms - Positive antibody test for HIV - Without treatment it can last anywhere between 1 to 20y 3) Early symptomatic HIV disease - Persistent generalized lymphadenopathy - Oral lesions (candida infections) - Reactivation of varicella-zoster virus (shingles) - Haematological disturbances (thrombocytopenia, anaemia) 4) Advanced HIV disease or AIDS (CD4 count < 200 cells/mm3) - Neurological manifestations (AIDS encephalopathy) - Weight loss - Opportunistic infections (tuberculosis) - Malignancies (lymphomas, kaposis’ sarcoma) - Fatigue - Dermatological conditions
36
HIV treatment
- Highly active antiviral therapy. (HAART): usually started in early symptomatic HIV disease => Suppress HIV replication => Undetectable levels of HIV in blood
37
HIV prognosis
- Manageable chronic illness for patients having access to treatment & adhere to treatment - Leading cause of death is now kidney or liver failure, due to medications
38
HIV: standard precautions
- Use protective barriers (gloves, eye shields, gowns), when handling blood, body fluids & infectious fluids - Wash hands, skin & mucous embraces immediately & thoroughly if contaminated by blood or other body fluids - Prevent needle or scalpel sticks - Any health care worker with open wounds or skin lesions should not treat clients or handle equipment until lesion heals