Lymphoid System

Question 1

Where do B cells mature?

Answer 1

Bone Marrow

Question 2

Where do T cells mature?

Answer 2

Thymus

Question 3

What areas are considered Primary Lymphoid Tissue?

Answer 3

Central Bone Marrow

Thymus

Question 4

What areas are considered Secondary Lymphoid Tissue

Answer 4

• Lymph nodes
• spleen
• tonsils (Waldeyer’s ring)
• epithelio-lymphoid tissue (e.g. in bowel/ skin)
• peripheral bone marrow

Question 5

What are the functions of the Lymph system?

Answer 5

• return lymph to circulation
• prevents accumulation of fluid in tissue (oedema)
• permits cell traffic
• allows cell trapping (i.e. traps abnormal cells in lymph)
• cells can interact with immune system

Question 6

When does lymphoedema commonly appear?

Answer 6

post axillary surgery for breast cancer
=> no lymph nodes to drain fluid from arm
=> swelling

Question 7

What is chylous ascites and when does it occur?

Answer 7

• lipid rich lymph
• accumulates in peritoneum
• due to trauma/obstruction

Question 8

What major lymph node groups must be visualised radiologically?

Answer 8

Mediastinal

para-aortic

Question 9

How large can lymph nodes become when swollen?

Answer 9

2.5cm

Question 10

Describe the passage of lymph through a lymph node

Answer 10

IN = afferent lymph vessel
travel round peripheral sinus
diffuse through parenchyma
to EFFERENT lymph vessel

Question 11

What type of immune cell links the innate and adaptive immune system?

Answer 11

Antigen Presenting Cells (APC’s)

present antigen to mature B/T cells in lymph node to create memory bank cells and Ab

Question 12

B Cells accumulate where in lymph nodes?

Answer 12

Germinal Centres

- allows them to differentiate into IgG and memory B cells

Question 13

Aside from B and T cells, what other cells are found in a lymph node?

Answer 13

Natural Killer Cells (NKCs)
Macrophages
APCs
Dendritic Cells

Question 14

What surface antigens are used to differentiate B and T lymphocytes on immunophenotyping?

Answer 14

B cell - CD20

T cell - CD3

Question 15

What are the potential causes of lymphadenopathy?

Answer 15

• local inflammation (e.g. bacterial infection)
• systemic inflammation (e.g. viral infection, autoimmune)
• malignancy (haem or non-haem)
• metastatic disease

OTHERS: sarcoidosis

Question 16

What percentage of sarcoidosis cases experience lyphadenopathy

Answer 16

15%

Question 17

Sarcoidosis can potentially hide a malignancy in a lymph node. TRUE/FALSE?

Answer 17

TRUE

- granulomatous disease can make it difficult to identify other pathology in node

Question 18

How can regional lymphadenopathy be identified on examination?

Answer 18

• red lines may extend from inflamed lesion due to pattern of draining
  => lymphangitis
• superficial lymphadenopathy (e.g. first sign of underling cancer e.g. breast)

Question 19

A predominant B cell response in a lymph node that is enlarged would make you consider what causes?

Answer 19

• autoimmune

- infection

Question 20

A predominantly phagocytic response in an enlarged lymph node would make you consider what causes?

Answer 20

Drainage of a tumour site

Question 21

A T cell response in an enlarged lymph node was cause you to consider what pathology?

Answer 21

• viral infection

- drug induced (phenytoin)

Question 22

GIve an example of a disease during which the spleen is more likely to rupture? How is this prevented?

Answer 22

• glandular fever (EBV)

- encourage patients to not participate in contact sport

Question 23

What types of tissue make up the spleen and what is found in each?

Answer 23

Parenchyma includes red pulp and white pulp

Red pulp contains sinusoids and cords which have cells in transit

White pulp contains T helper cellls

Question 24

What is the main function of the spleen?

Answer 24

Filters blood like lymph node filters lymph

Question 25

What symptoms do patients experience in splenomegaly?

Answer 25

- dragging feeling - pain/discomfort on eating - low blood count often seen (due to increased splenic breakdown of blood cells)

Question 26

What can cause splenomegaly?

Answer 26

- infection - congestion (portal hypertension) - haematological cancer - inflammation (RA, SLE) - Storage disease (e.g. Goucher's Niemann-Pick disease)

Question 27

What causes HYPOsplenism?

Answer 27

``` - usually occurs due to splenectomy OTHERS: - coeliac - sickle cell - sarcoid - iatrogenic ```

Question 28

What is usually required in hyposplenism to prevent infection?

Answer 28

various vaccinations | prophylactic antibiotics

Question 29

What are Howell Jolly Bodies and what do they indicate

Answer 29

DNA nucleated RBCs - these are usually removed by spleen => in HYPOsplenism these are not removed