The Lymphoid System

Question 1

Where does B cell maturation occur?

Answer 1

Bone marrow

Question 2

Where does T cell maturation occur?

Answer 2

Thymus

Question 3

What are the primary lymphoid tissues?

Answer 3

Bone marrow

Thymus

Question 4

What are the secondary lymphoid tissues?

Answer 4

Lymph nodes
Spleen 
Tonsils (waldeyer's ring) 
Epithelio-lymphoid tissues
Bone marrow

Question 5

What is the function of the lymph system?

Answer 5

Fluid haemostasis
Prevents excessive accumulation of fluid in tissues
Permits cell traffic and trapping
Allows for interaction of cells and molecules with immune cells

Question 6

What are lymph nodes?

Answer 6

Small oval bodies, up to 2.5cm in size

Question 7

What is located along the course of lymphatic vessels?

Answer 7

Blind ending vascular channels that collect fluid from tissues and return it to the blood stream
Passive movement of fluid
Valves ensure direction of flow

Question 8

What is the role of afferent channels in lymph nodes?

Answer 8

Drain lymph through capsule into the peripheral sinus

Question 9

Where will lymph drain to from the lymph nodes?

Answer 9

Cisterna chyli/ thoracic duct
Left jugular, subclavian or bronchomediastinal trunks
Right jugular, subclavian or bronchomediastinal trunks

Question 10

How will lymph go from the lymphatic system to the venous system?

Answer 10

Thoracic angle; junction of L/R subclavian and jugular veins

Question 11

Where do arterial and venous vessels that serve the node enter/exit?

Answer 11

Hilum

Question 12

What is lymph filtered through before it returns to the blood stream?

Answer 12

Lymph node parenchyma

Question 13

How does the lymphoid system act as a defensie system?

Answer 13

House cells of innate immune system
Traffic of APCs links innate and adaptive immune responses
Allows for specificity, inducibility, memory and an enhanced secondary reaction

Question 14

Where can B cells be found in the lymphatic system?

Answer 14

Follicles and germinal centers
Interfollicular
Plasma cells in the medulla of lymph nodes

Question 15

What cell populations are found in lymph nodes?

Answer 15

B cells
T cells 
NK cells
Macrophages 
Dendritic cells 
Endothelial cells

Question 16

What is CD20 a marker of?

Answer 16

B cells

Question 17

What is CD3 a marker of?

Answer 17

T cells

Question 18

What can cause local lymphadenopathy?

Answer 18

Infection; TB, toxoplasma
Vaccination
Dermatopathic

Question 19

What is dermatopathic lymphadenopathy?

Answer 19

A distinctive reaction pattern in lymph nodes characterized by paracortical hyperplasia composed of dendritic cells, Langerhans cells, macrophages containing melanin pigment, and T-cells

Question 20

What can cause systemic lymphadenoapthy?

Answer 20

Infection; viral 
Autoimmune 
Sarcoidosis 
IgG4 related disease 
Castelmans disease

Question 21

What can cause malignant lymphadenopathy?

Answer 21

Haem; lymphoma/ leukaemia

Metastatic

Question 22

What is sarcoidosis?

Answer 22

Granulomatous disease

Can mask malignancy in a lymph node

Question 23

What is lymphangitis?

Answer 23

Superficial infection that tracts in lymph system

Question 24

What can superficial lymphadenopathy be the first sign of?

Answer 24

Malignancy

Question 25

What does generalised lymphadenopathy suggest?

Answer 25

Systemic inflammation or widespread malignancy

Question 26

If you suspect lymphoma/ leukaemia due to generalised lymphadenopathy, what should you do?

Answer 26

Check the FBC

Question 27

How can you differentiate a lymph node enlargement from a reactive process and a neoplastic process?

Answer 27

Reactive; different patterns Neoplastic; filtration function hampered Primary Look at B cell response and T cell response separately

Question 28

What does a predominant B cell response in lymph node enlargement suggest?

Answer 28

Autoimmune conditions | Infections

Question 29

What does a predominant phagocytic response in a lymph node enlargement suggest?

Answer 29

Drainage of tumour site

Question 30

What does a predominantly T cell response in a lymph node enlargement suggest?

Answer 30

Viral infection | Drugs; phenytoin

Question 31

Where is the spleen located?

Answer 31

Left upper quadrant Diaphragmatic surface Visceral surface; left kidney, gastric fundus, tail of pancreas, splenic flexure of colon

Question 32

What supplies the spleen?

Answer 32

``` Splenic artery (branch of coeliac axis) Draine by splenic vein (joins with SMV to form portal vein) ```

Question 33

Is the spleen encapsulated?

Answer 33

Yes

Question 34

What is contained within the spleen parenchyma?

Answer 34

Red pulp | White pulp

Question 35

What does red pulp contain?

Answer 35

Sinusoids and cords

Question 36

Describe the sinusoids in the spleen

Answer 36

Fenestrated Lined by endothelial cells Supported by hoops of reticulin

Question 37

What do the cords of the spleen contain?

Answer 37

Macrophages Fibroblasts Cells in transit; RBC, WBC, PC, CD8+ T cells

Question 38

What is the function of the spleen?

Answer 38

Filter for blood Detects, retains and eliminates unwanted foreign or damaged material Facilitates immune responses to blood borne antigens

Question 39

What does the white pulp of the spleen contain?

Answer 39

Periarteriolar lymphoid sheath (PALS) = CD4+ T cells | Expanded by lymphoid follicles in reactive changes

Question 40

How do antigens reach the white pulp of the spleen?

Answer 40

Blood APCs in white pulp will present antigen to immune reactive cells when stimulated by antigen, T c and B cells respond

Question 41

What are the symptoms of splenic enelargement?

Answer 41

Dragging sensation in LUQ Discomfort with eating (pressure on gastric fundus) Pain if infarction Hypersplenism

Question 42

What is the triad of hypersplenism?

Answer 42

Splenomegaly Fall in one of more cellular components of blood Correction of cytopenias by splenomegaly

Question 43

What infections can cause splenomegaly?

Answer 43

``` EBV Malaria TB Typhoid Brucellosis Leishmaniasis Trypanosomiasis ```

Question 44

What diseases can result in congestion and subsequent splenomegaly?

Answer 44

Portal: Hepatic cirrhosis Portal/ splenic vein thrombosis Cardiac failure

Question 45

What haem disorders can result in splenomegaly?

Answer 45

``` Lymphoma Leukaemia Haemolytic anaemia ITP Myeloproliferative disorders ```

Question 46

What inflammatory conditions can result in splenomegaly?

Answer 46

RA | SLE

Question 47

What storage diseases can result in splenomegaly?

Answer 47

Gaucher's | Niemann-Pick disease

Question 48

Broadly, what can cause splenomegaly?

Answer 48

``` Infection Congestion Haem diseases Inflammatory conditions Storage disease Amyloid Tumours Cysts ```

Question 49

What can cause hypersplenism?

Answer 49

Associated with splenomegaly | Key diagnostic feature of hypersplenism if splenectomy

Question 50

What can cause hyposplenism?

Answer 50

``` Splenectomy Coeliac disease Sickle cell Sarcoid Iatrogenic ```

Question 51

What causes the symptoms seen in hyposplenism?

Answer 51

RED pulp dysfunction; howell jolly bodies