Week 4: Immunodeficiences

Question 1

What is flow cytometry?

Answer 1

Tagging a cell population with an immunoflurescent label (by reacting with a fluorescently labelled monoclonal antibody)

Question 2

What are symptoms of chronic granulomatous disease? (5)

Answer 2

Fever, lymphadenopathy
Commensal bacterial infections
Burkholdaria cepacia
Giant cell granulomas

Question 3

What defect occurs in chronic granulomatous disease? What is such a patient still able to do?

Answer 3

Absent respiratory burst (defect in enzyme subunit) in phagosomes

(but able to phagocytose)

Question 4

Would we assay for LFA-1 when we see osteomyelitis granuloma in the liver?

Answer 4

No, why would we when clearly neutrophils can migrate (so adhesion molecule LFA-1 is intact)

Question 5

What are symptoms of leukocyte adhesion deficiency?

Answer 5

If discharge is clear and lacks cells (NO PUS!)
Slow healing e.g. umbilical cord stump
High leukocyte level
Recurrent infections

Question 6

What happens in leukocyte adhesion deficiency?

Answer 6

Neutrophils have trouble leaving the blood stream

Granulation tissue can’t form

No influx of macrophages for healing

Question 7

What would we see in the flow cytometry results of leukocyte adhesion deficiency?

Answer 7

Absent expression of CD18 on lymphocytes, absent expression of CD18 on monocytes

Question 8

What are symptoms of Hyper IgM syndrom?

Answer 8

History of unusual infections
Family history of e.g. early death
Lack of fever, no lymphadenopathy
Little serum response to vaccinations e.g. tetanus

Question 9

What do we see on an FBE of someone with Hyper IgM syndrome?

Answer 9

Low neutrophil count
High lymphocyte count
(slightly) High monocyte count

Question 10

Does flow cytometry indicate whether T and B cells are capable of differentiation?

Answer 10

No, they don’t indicate the functionality (only the amount)

Question 11

What do we see in the serum immunoglobulins in Hyper IgM syndrome?

Answer 11

Very high IgM

Low/no IgG, IgA

Question 12

What happens with T cells in Hyper IgM syndrome?

Answer 12

CD40L may not be expressed, so CD 4 T-cell activation can’t occur.

Thus, B cells cannot be activated and isotype switching doesn’t occur.

Question 13

What are symptoms of no IFN-y R’ and low TNFa?

FBC and clinical symtptoms

Answer 13

High monocyte count, increased IgM, IgG, increased WBC count

Really large lymphnodes, microbial infections, salmonella, VZV

NO GRANULOMAS developing (TNF critical for this)

Question 14

What can occur in immunocompromised patients (e.g. after cytotoxic chemotherapy)

Answer 14

Patient can be infected with common viruses such as VZV, HSV etc.