Immunology

Question 1

The difference between secondary and primary immunodeficiency disorders?

Answer 1

Secondary are induced by the environment

Primary are caused by defects in your innate or adaptive immunity

Question 2

What is neutropenia?

Answer 2

An abnormally low concentration of neutrophils in the blood

Question 3

Describe presentation of severe congenital neutropenia and treatment

Answer 3

• Severe chronic neutropenia from birth
• Will have a low neutrophil count
• Will present with recurrent bacterial/ fungal infections but no pus within two weeks of birth
• Treatment with recombinant G-CSF reduces infections and improves survival

Question 4

Describe treatment and presentation of leukocyte adhesion deficiency

Answer 4

• Integrin deficiency means failure of neutrophil adhesion and migration
• Patients will have severe recurrent infections that can’t be cleared
• Really high neutrophil population in the blood
• No pus at the site of infection

Question 5

Describe treatment and presentation of chronic granulomatous disease

Answer 5

• Deficiency of the intracellular killing mechanism of phagocytes - absent respiratory burst. Mechanism mediated by NADPH complex
• Clinical features include recurrent deep bacterial infections especially Staphylococcus, Aspergillus, pseudomonas cepacian, mycobacteria, atypical mycobacteria
• Recurrent fungal infections
• Failure to thrive
• Lymphadenopathy and hepatosplenomegaly (liver, spleen and lymph nodes abnormally large)
• Granuloma formation

Question 6

Leukocyte adhesion deficiency is ______ common than CGD and severe congenital neutropenia

Answer 6

much less

Question 7

The most severe form of immunodeficiency is _______ and is failure _________ and is fatal unless corrected with __________

Answer 7

Reticular dysgenesis
of production of all leukocytes
stem cell transplantation

Question 8

Severe combined immunodeficiency is ________ and is most commonly caused by _______

Answer 8

failure of production of lymphocytes

x-linked mutation

Question 9

DiGeorge syndrome causes defects in _____ and is a result of an absent ______ and means _____-

Answer 9

t cell development
thymus
macrophages are very susceptible to intracellular bacteria and there will be lots of viral infections as no t cells to kill off infected tissue cells

Question 10

X-linked agammaglobulinaemia is _____ Typical presentations include _______ Infections are typically caused by___________

Answer 10

failure of production of mature b cells
• Typical presentations include upper and lower respiratory infections, diarrhea, cellulitis, meningitis, and sepsis.
• Infections are typically caused by Gram-positive, highly pathogenic encapsulated organisms such as Streptococcus pneumonia and Haemophilus influenzae type b.

Question 11

Defects in t cell effector functions involve ____

Types of infection include ________

Answer 11

•	Deficiency in IL-12 receptor or IFNg
	Tuberculosis
	Atypical mycobacteria 
	BCG infection after vaccination
	Deep fungal infections e.g. aspergillus

Question 12

Defects in B cell effector function are from defects in ____ and can be ______ or ______

Answer 12

Class switch recombination
Hyper IgM- severe reduction in IgG and IgA and normal/ elevated IgM
Defective IgA deficiency- 2/3rd individuals asymptomatic, 1/3rd have recurrent respiratory tract infections

Question 13

Overall clinical features of T cell deficiencies are

Answer 13

•	Recurrent infections
–	Viral 
–	Fungal
–	Bacterial
–	Intracellular pathogens eg mycobacteria
•	Opportunistic infections
•	Malignancies at young age
•	Autoimmune disease

Question 14

Overall clinical features of B cell deficiencies are

Answer 14

•	Recurrent infections
–	Primarily bacterial infections
–	Often very common organisms
•	Opportunistic infections
•	Antibody-mediated autoimmune disease

Question 15

Gram versus host disease?

Answer 15

You see your own body as foreign

Question 16

Describe type 1 hypersensitivity

Answer 16

Ig-E response to an external antigen
• Adaptive immune mediators are CD4+ T cells, TH2 cells, B cells, IgE antibodies
• Innate immune mediators are mast cells and eosinophils
Reaction is caused by binding of allergen to Ig-E coated mast cells

Question 17

Describe treatment of type 1 hypersensitivity

Answer 17

• Avoidance of allergen
• Montelukast for leukotriene receptors, anti-histamines for histamine, sodium cromoglicate, prednisolone)
• Management of anaphylaxis is with epi pen
• Immunotherapy

Question 18

Describe type 2 hypersensitivity reaction

Answer 18

• Immune system generates antibodies to self-antigens
• Adaptive immune mediators are CD4+ T cells, TFH cells, B cells, IgM and IgG antibodies
• Innate immune mediators are complement, phagocytes, NK cells

Question 19

Describe type 3 hypersensitivity reaction

Answer 19

• Immune complexes are deposited in the blood vessel walls
• The presence of immune complexes activates complement and attracts inflammatory cells such as neutrophils
• Enzymes released from neutrophils cause damage to endothelial cells of basement membrane
• Acute hypersensitivity pneumonitis is an example
• Adaptive immune mediators are CD4+ T cells, TFH cells, B cells, IgG antibodies
• Innate immune mediators are complement and neutrophils

Question 20

Describe treatment of type 2 hypersensitivity

Answer 20

Corticosteroids, Cyclophosphamide, Plasmapheresis

Question 21

Describe type 4 hypersensitivity

Answer 21

This is a delayed response e.g. TB or sarcoidosis

Driven by macrophages, CD4, TH1

Question 22

Describe central and peripheral tolerance

Answer 22

• Central tolerance: Deletion of self-reactive lymphocytes in primary lymphoid tissues
• Inactivation of self-reactive lymphocytes in peripheral tissues that escape central tolerance is by peripheral tolerance and is carried out by regulatory t cells

Question 23

Describe goodepasture’s syndrome

Answer 23

Anti-GBM
Type 2 hypersensitivity reaction affects the lungs and kidneys
– pulmonary alveolar haemorrhage
– kidney disease (glomerulonephritis)
• Defined by the presence of autoreactive antibodies to the α3 chain of type IV collagen present in the basement membranes of alveoli and glomeruli
• Thought to result from an environmental insult (smoking, infections, exposure to certain drugs) in a person with genetic susceptibility

Question 24

Treatment of goodepastures syndrome?

Answer 24

Corticosteroids, Cyclophosphamide, Plasmapheresis, Stop smoking

Question 25

Describe Systemic lupus erythematosus (SLE)

Answer 25

Target= nuclear antigens
Prototypic multi-system autoimmune disease
Skin rashes, nephritis, alveolitis
Type 3 hypersensitivity disease

Question 26

Describe rheumatoid arthritis resp effects

Answer 26

Type 4- rheumatoid nodules within the lung, inflammation of the pleural cavity

Question 27

What is a mast cell degranulation product that can be measured during an acute episode of anaphylaxis?

Answer 27

Serum tryptase

Question 28

What is transient hypogammaglobulinemia of infancy?

Answer 28

Relatively common primary immunodeficiency disease that affects infants and young children. Following birth, maternal immunoglobulin G (IgG) is catabolized, and IgG synthesized by the infant gradually accumulates. In the time it takes for reaccumulation there will be chronic infections.