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Flashcards in HS II Deck (14):
1

What type of reaction is a type II hypersensitivity reaction?

Antibody mediated, targets cell bound antigens

2

What immunoglobulin is involved in type II HS reactions and how does this cause a reaction?

IgG/IgM antibodies
Bind to cell bound antigens, cause complement activation which damages tissue
-Cell lysis via membrane attack complex
-Neutrophil recruitment C3a/C5a, release of toxins
-Opsonisation C3b
Antibody dependant cytotoxicity

3

Describe the pathophysiology of haemolytic disease of newborn

Rhesus D negative mother becomes sensitised to Rhesus D antigen in first positive pregnancy
Second pregnancy she produces IgG antibodies that cross the placenta and attack fetal blood cells

4

Describe the disease process of haemolytic transfusion reaction

Incompatibility in ABO group/Rhesus D antigen
Host produces IgM antibodies against donor RBCs, causing cell lysis, kidney failure, circulatory collapse

5

Describe the pathophysiology of Graves' disease

IgG antibodies bind to thyroid stimulating hormone receptors, so thyroid gland produces thyroid hormones, causing hyperthyroidism

6

What are the clinical features of Graves' disease?

Weight loss
Goiter
Anxiety/irritability
Fine hand tremor
Heat sensitivity

7

How is Graves' disease treated?

Anti-thyroid - Carbimazole
Radioactive iodine to destroy thyroid cells
Thyroidectomy

8

How long does a type II HS reaction take to develop?

5-12 hours

9

How does Graves' disease affect pregnancy?

Maternal antibody to thyroid stimulating hormone is IgG so crosses the placenta, causing receptor activation and hyperthyroidism in the baby

10

Describe the pathophysiology of myasthenia gravis

Anti-acetylcholine receptor antibody binds to Ach receptor, impairing neuromuscular signalling

11

Describe the symptoms of myasthenia gravis

Ptosis
Diplopia
Dysphagia
Facial paralysis
Hoarse voice
Trouble walking/ lifting objects

12

Describe how myasthenia gravis is treated

Corticosteroids eg prednisolone
Azathioprine for immunosuppression
Thymectomy

13

Describe treatment of type II HS reactions and why this helps

Immune suppression - reduces complement activation
Plasmapheresis - removes circulating antibodies and inflammatory mediators
IV immunoglobulin - promote IgG degredation

14

Describe the pathophysiology of Goodpasture's syndrome

Anti glomerular basement membrane antibodies bind to GBM, activate compliment pathway, causing cell death