Food allergy

Question 1

what is the name if you are not allergic to something, just don’t like it

Answer 1

psychosomatic effect

Question 2

what causes a food allergy

Answer 2

when your immune system attacks a food protein

Question 3

what links the symptoms to the allergy

Answer 3

no correlation

Question 4

what is the gut challenged by

Answer 4

constant bombardment of foreign antigens

Question 5

what happens when the mucosal mast cells are activated

Answer 5

triggers release of inflammatory mediators

• transepithelial fluid loss
• smooth muscle contraction
• vomiting and diarrhoea
• anaphylaxis

Question 6

when do we know from adverse reactions to food if there is a problem

Answer 6

when the immune system is involved = food allergy

if non-immune mediated = food hypersensitivity

Question 7

what is the first point of contact with food

Answer 7

gut

food consumed travels to mucosa

Question 8

what is the mucosa

Answer 8

inner most layer of the gut

Question 9

what defence is there against microbes in the gut

Answer 9

most microbes destroyed by acid in gut

Question 10

where in the body is there the largest population of immune cells

Answer 10

gut

Question 11

where do the lymphatics from the peyers patch and villi go

Answer 11

drain into the mesenteric lymph node

Question 12

what is the lamina propria

Answer 12

close network of loose connected tissues in the villi

Question 13

what replenish the villi - damaged epithelial cells

Answer 13

crypts - host stem cells

Question 14

how does the intestine prevent invasion

Answer 14

epithelium with thick overlying mucus form barrier against microbial invasion

Question 15

what cells are make up the peyers patch

Answer 15

mix of immune cells

Question 16

what does the peyers patch have that aids its function

Answer 16

thinner mucus layer and phagocytic cells

Question 17

what is the peyer patches - M cell function and process

Answer 17

sampling antigens in lumen then transport to antigen-presenting cell on the basolateral side via transcytosis

Question 18

what do dendritic cells do

Answer 18

extend dendrites between epithelial cells to sample antigens that are then broken and presented to lymphocytes
usually causes an anti-inflammatory response

Question 19

when might inflammatory bowel disease be caused

Answer 19

dendritic cells with antigen travel to T cells in peyers patch
if T cells non-functional can cause inflammatory bowel disease

Question 20

how is inflammation stopped

Answer 20

T cells migrate to villi
secretion suppresses immune cells
stop inflammation

Question 21

how are inflammatory molecules released

Answer 21

epithelium contact with bacteria
activates immune cells
release inflammatory molecules

Question 22

what are neturophils and their function

Answer 22

types of WBC

needed for clearance of bacteria

Question 23

how do neutrophils prevent the inflammatory condition getting worse

Answer 23

undergo self cell death - leave neutrophil extracellular trap

Question 24

what happens to fight against parasites

Answer 24

attracted to parasite
release large amount WBC to destroy it
antibodies recognise some characteristics of cells and bind, label cells for destruction
cells e.g. mast, recognise the antibodies
release mediators
destroy invader

Question 25

which antibodies are involved in allergic reaction

Answer 25

immunoglobin E antibodies

Question 26

when does IgE mediated hypersensitivity occur

Answer 26

antigen makes contact, taken up and processed by antigen-presenting cells
if allergic also presents co-stimulatory molecules on surface to Thelper cells
T cells make IgE antibodies specific to allergen
T helper cell makes cytokines
stimulate B cells to multiply and differentiate IgE-plasma producing cells
IgE attach via constant regions to mast cell receptors
mast cells have granules packed with chemicals that cause hypersensitivity response

Question 27

where in the body can produce many IgE antibodies

Answer 27

tissues under mucus membrane are rich in B cells

Question 28

when does the individual become sensitised to the antigen and how does this trigger an allergic reaction

Answer 28

IgE can survive for weeks
when exposed to antigen second time
antigen bond to IgE antibodies on mast cells
two cell bound IgE molecules must react with antigen trigger response
mast cell release histamine - and other inflammatory response from granules
trigger allergic reaction symptoms

Question 29

what are the symptoms of allergy

Answer 29

hives
eczema
asthma
anaphylactic shock

Question 30

what causes an anaphylactic shock

Answer 30

airway constriction and increase in vascular permeability

Question 31

why are stats of allergies inaccurate

Answer 31

affected by:
other allergic diseases
exposure route
age
etc..

Question 32

what factors are important in allergies

Answer 32

• need to know if skin or oral exposure important
• is the lipid load of allergen matrix related to their ability to sensitise – do we know what makes an allergen
• is the narrow age window for tolerance vital