Role of Intestinal Mucosal Immunity

Question 1

what is the role of intestinal mucosal immunity in disease

Answer 1

infectious disease
primary immunodeficiency 
allergy
coeliac disease
Irritable bowel disease

Question 2

role of innate mechanisms in mucosal immunity

Answer 2

eliminate most intestinal infections rapidly

Question 3

how are innate mechanisms activated

Answer 3

ligation of pattern recognition receptors

Question 4

how is the NFkB pathway actviated

Answer 4

via intracellular sensory in epithelial cells - PRR

Question 5

what happens when mucosal immunity becomes dysregulated - selective IgA deficiency

Answer 5

common

asymptomatic remainder recurrent sinopulmonary infections

Question 6

what happens when mucosal immunity becomes dysregulated - CVID

Answer 6

recurrent sinopulmonary and GI infections;
failure to differentiate into Ig secreting cells
low IgG, IgA, IgM and IgE
defective antigen specific antibody response

Question 7

what happens when mucosal immunity becomes dysregulated - XLA

Answer 7

sinopulmonary and GI infections and devastating systemic manifestations of chronic enteroviral infections;
no B cells/agammaglobulinaemia

Question 8

what happens when mucosal immunity becomes dysregulated - CGD

Answer 8

staphylococcus aureus/inflammatory granulomas-pneumona, liver abscess, perianal abscess and skin abscess;
failure of phagocyte respiratory burst

Question 9

what happens when mucosal immunity becomes dysregulated - SCID

Answer 9

profound defect in T and B cell immunity;
oral candidiasis/chronic diarrhoea/intestinal pneumonitis
GI-CMV/rotavirus/EBV

Question 10

mucosal immune response to food allergy

Answer 10

type I hypersensitivity reaction initiated by cross-linking of allergen specific IgE on the surface of mast cells with the specific allergen
memory response - immune system primed

Question 11

what is coeliac disease

Answer 11

gluten sensitivity causing damage to small intestine and leading to malnutrition

Question 12

is coeliac disease an allergy

Answer 12

no

trigger is unknown (enteric viruses?)

Question 13

immunopathology to coeliac disease

Answer 13

immunopathology T cell/IEL mediated
gamma interferon from gluten specific T cell activate epithelial cells which produce IL-15 which induces proliferation and activation of IEL
both T cells and IEL can kill epithelial cells

Question 14

damage of small intestine due to coeliac disease

Answer 14

loss of villi
normal columnar enterocytes replaced by ragged, lymphocyte infiltrated enterocytes - resulting in abnormal transport from the lumen into the body

Question 15

tests for coeliac disease

Answer 15

biopsy

serology

Question 16

where does Crohn’s disease effect in the body

Answer 16

effects any part of GI tract - most common distal ileum and colon

Question 17

what is Crohn’s disease

Answer 17

focal and discontinuous inflammation with deep ad eroding fissures +/- granulomas

Question 18

immunopathology of Crohn’s disease

Answer 18

mediated by Th1 CD4+ T cells/gamma interferon/IL-12/TNF alpha
multiple genetic deficiency and immunologic mechanisms - multifactorial -HLA

Question 19

where does ulcerative colitis effect in the body

Answer 19

restricted to rectum and colon;

starts in rectum and moves proximally and contiguously - can develop extra-intestinal manifestations

Question 20

what is ulcerative colitis

Answer 20

distortion of the crypts with infiltration of monocytes/neutrophils and plasma cells
inflammaiton and ulceration in surface mucosa

Question 21

immunopathology of ulcerative colitis

Answer 21

unclear

may be NK T cell mediated disease via IL-13