1. Hypersensitivity

Question 1

clinical examples of type 2 hypersensitivity, related to complement activation

Answer 1

HDN- antigen: rhesus D

Transfusion reaction- antigen: ABO

Question 2

clinical examples of type 2 hypersensitivity, related to antibody-dependent cell cytotoxicity

Answer 2

autoimmune haemolytic anaemia- antigen: RBCs

immune thrombocytopenia- antigen: platelets

good pasture’s syndrome- antigen: collagen in BM kidney+ lung

Question 3

for each blood type, state the antibodies and antigens

Answer 3

A
Ag- A
Ab- anti-B

B
Ag- B
Ab- anti-A

AB
Ag- A and B
Ab-

0
Ag-
Ab- anti A and anti B

Question 4

explain how haemolytic disease of the newborn occurs

Answer 4

-Rhesus factor D negative mother carries a positive fetus
-some fetal blood enters mothers blood (maybe during delivery)
-mother produced es anti-Rh antibodies from this sensitisation event
-if she has another positive fetus, anti-Rh antibodies cross placenta and damage fetal RBCs

Question 5

severe consequences of HDN

Answer 5

-kernicterus
-hydrops fetalis
-splenomegaly
-severe hyperbilirubinaemia

Question 6

kernicterus

Answer 6

high bilirubin in fetal blood leads to poor brain development

Question 7

example of disease caused by protein blockade, and the antigen

Answer 7

pernicious anaemia

intrinsic factor in gastric parietal cells

Question 8

define immune complex

Answer 8

multi molecular complex of antibodies and bound antigen

Question 9

which patient factors usually lead to a poor prognosis of RA?

Answer 9

female
less than 30
high titre of RF
joint erosions
DR4 allele

Question 10

how to diagnose contact hypersensitivity

Answer 10

patch test

Question 11

antigen for insulin dependent diabetes mellitus

Answer 11

pancreatic islet cells

Question 12

antigen for hashimotos thyroiditis

Answer 12

thyroid gland

Question 13

in type 1 hypersensitivity reactions, how is IgE produced instead of IgG

Answer 13

TH2 response (Interleukins 4,5,13) cytokines instruct B cells to produce IgE

Question 14

hygiene hypothesis

Answer 14

allergies are more likely in westernised countries due to less exposure to microbes during childhood

Question 15

immunoglobulin in TH1 response and TH2

Answer 15

TH1: IgG

TH2: IgE

Question 16

explain how the strategic locations of mast cells also contribute to their hypersensitivity effects

Answer 16

in connective tissue around blood vessels: kills patients

near ports of entry

Question 17

new blood test for showing systemic activation

Answer 17

try-tase

Question 18

features of adrenaline for anaphylactic shock

Answer 18

-reverse peripheral vasodilation
-relieve airways obstruction, bronchospasm
-increase force of myocardial contraction
-inhibits mast cell activation

Question 19

describe allergen desensitisation. what’s the important mechanism?

Answer 19

administration of increasing doses of allergen extracts over years, to get rid of their anaphylactic reaction

shift from TH2 to TH1 reaction, so produce IgG not IgE

Question 20

factors for development of allergic disease

Answer 20

changes to microbiome

reduced infectious burden

Question 21

main reason for systemic reaction in type 1 hypersensitivity

Answer 21

systemic mast cell activation inappropriately