Immunology 7 - Malabsorption CPC

Question 1

What type of disease is coeliacs?

Answer 1

Polygenic autoimmune

Question 2

Hb
Fe
TIBC/transferrin
Transferrin saturation
Ferritin in IDA

Answer 2

Hb low
Fe low
TIBC/Transferrin raised
Transferrin saturation low
ferritin low

Question 3

Hb
Fe
TIBC/transferrin
Transferrin saturation
Ferritin in ACD

Answer 3

Hb low
Fe low
TIBC/transferrin normal or low
Transferrin saturation normal
Ferritin Normal OR high (APP)

Question 4

Causes of low MCV anaemia

Answer 4

IDA
Thalassaemia
ACD

Question 5

For iron studies, what stain is used?

Answer 5

Giesma stain (Shows nuclei as dark blue)

Question 6

What signs on blood film in iron deficiency?

Answer 6

Hypochromic microcytic anaemia
anisopoikilocytosis
NO basophilic stippling

Question 7

Blood film in megaloblastic, hyposplenism

Answer 7

Hypersegmented neutrophils
Target cells (codocytes)
Howell-Jolly bodies

Question 8

What are main blood film findings in coeliacs indicative of?

Answer 8

Iron deficiency, B12/folate deficiency, hyposplenism

Question 9

Hypochromic, microyctic cells … ddx?

Answer 9

IDA, thalassaemia trait

Question 10

Poikilocytes (Tear drop cells) + Anisopoikilocytes (elliptocytes)

Answer 10

IDA

Question 11

Basophilic stippling

Answer 11

Beta thal trait
Lead poisoning
Alcoholism
sideroblastic anaemia

Question 12

Target cells/codocytes differentials

Answer 12

Iron deficiency
Thalassaemia
Hyposplenism
Liver disease

Question 13

Howell-Jolly bodies sign of…

Answer 13

Hyposplenism

Question 14

Blood film in hyposplenism

Answer 14

Target cells and Howell jolly bodies

Question 15

Causes of hyposplenism

Answer 15

Trauma/therapeutic (absent spleen)

Poorly functioning spleen (IBD, Coeliac’s, SCD, SLE)

Question 16

Deficiencies seen in coeliacs

Answer 16

Vitamin D def
Vit B12/folate
Hyposplenism
Iron deficiency

One unifying diagnosis = malabsorption

Question 17

Deficiencies seen in Crohn’s and why

Answer 17

Bile salts and B12 (TERMINAL ILEUM COMMONLY AFFECTED)

Question 18

What is faecal elastase a test for?

Answer 18

Pancreatic insufficiency

Question 19

HLA associations with coeliacs

Answer 19

HLADQ2 (most common)

HLADQ8

Question 20

T-cell response to gluten

Answer 20

Peptides from gluten i.e. gliadin are deaminated by TTG
The deaminated gliadin via HLA molecules DQ2 or DQ8 are presented by APCs to CD4+ T cells
cD4+ T-cell activation –> secretion of IFN gamma and increased IL-15 secretion
IL-15 activates intraepithelial lymphocytes (IELs)
IELs kill epithelial cells via NKG2D receptors –> damage of gut wall

Question 21

IELs type of T cell

Answer 21

Gamma delta T cell

Question 22

B cell response to gluten

Answer 22

TTG deaminates gliadin
APC takes up gliadin peptides and primes CD4 Tcells
Primes T cells provide B cell help via CD40L:CD40 to B cells underoing GC reactions
B cells under. go isotype switching and affinity maturaiotn –> gliadin specifc memory and plasma cells

Question 23

Anti-gliadin antibodies

Answer 23

IgA more sensitive than IgG but both unrealiable

Question 24

Which antibodies most reliable to screen for coeliacs?

Answer 24

anti-TTG and anti-endomysial (anti-TTG gold standard)

Question 25

In which population are these serology tests redundant?

Answer 25

IgA deficient individuals (1 in 600)

Question 26

1st line DIAGNOSIS for coeliacs/gold standard

Answer 26

>/=4 dudoenal biopsy | multiple biopsies taken to ensure you get a coeliac diseased part

Question 27

Endoscopy findings of coeliacs

Answer 27

Lack of mucosal folds and flattened villi

Question 28

Histopathology of coeliacs

Answer 28

Villous atrophy with crypt hyperplasia | Intra-epithelial lymphocytes

Question 29

Normal villi:crypt ratio and in coeliacs

Answer 29

Normal 3-5:1 | coeliacs: 1:1 or 1:3

Question 30

Normal IEL levels

Answer 30

<20 IELs/100 epithelial cells | Coeliac's >20/100

Question 31

One other cause of vilious atrophy

Answer 31

Tropical sprue

Question 32

Ohter causes of IELs

Answer 32

Giardiasis, CMPA, drugs (NSAIDs)

Question 33

What foods is gluten present in

Answer 33

Wheat, barley, rye and some oats

Question 34

Complications of coeliacs

Answer 34

``` Malabsorption Osteomalacia and osteoporosis Neurological disease Lymphoma (multifocal T-cell lymphoma - v difficult to treat) Hyposplenism ```

Question 35

How to test patient adhering to gluten free diet

Answer 35

Serology: TTG should be NEGATIVE

Question 36

whAT MIGHT A +ttg SUGGEST IN PT WITH COELIACS?

Answer 36

noT ADHERING TO DIET | lyMPHOMA

Question 37

What imagine do coeliac patients have and how often?

Answer 37

DEXA of spine and hip every 3-5 years

Question 38

How long after sticking to gluten free diet does mortality return to normal?

Answer 38

3-5 years

Question 39

Associations with coeliacs

Answer 39

Dermatitis herpetiformis T1DM Autoimmune thyroid disdase Down's syndrome