Flashcards in HS II Deck (14):
What type of reaction is a type II hypersensitivity reaction?
Antibody mediated, targets cell bound antigens
What immunoglobulin is involved in type II HS reactions and how does this cause a reaction?
Bind to cell bound antigens, cause complement activation which damages tissue
-Cell lysis via membrane attack complex
-Neutrophil recruitment C3a/C5a, release of toxins
Antibody dependant cytotoxicity
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
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
Describe the pathophysiology of Graves' disease
IgG antibodies bind to thyroid stimulating hormone receptors, so thyroid gland produces thyroid hormones, causing hyperthyroidism
What are the clinical features of Graves' disease?
Fine hand tremor
How is Graves' disease treated?
Anti-thyroid - Carbimazole
Radioactive iodine to destroy thyroid cells
How long does a type II HS reaction take to develop?
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
Describe the pathophysiology of myasthenia gravis
Anti-acetylcholine receptor antibody binds to Ach receptor, impairing neuromuscular signalling
Describe the symptoms of myasthenia gravis
Trouble walking/ lifting objects
Describe how myasthenia gravis is treated
Corticosteroids eg prednisolone
Azathioprine for immunosuppression
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