Core Immunology - Immunodeficiency (12)

Question 1

B lymphocytes

Answer 1

Develop potential to secrete antibodies (humoral immunity)

Question 2

Killer/cytotoxic T lymphocytes

Answer 2

Able to kill (cellular immunity)

Question 3

Helper T lymphocytes

Answer 3

Secrete growth factors/cytokines which control immune response - help B lymphocytes and T lymphocytes

Question 4

Which cells are the target of HIV?

Answer 4

Helper T lymphocytes

Question 5

Supressor T lymphocytes

Answer 5

Dampen down immune response

Question 6

Binding of antibodies to antigens inactivates antigens by…

Answer 6

• Neutralisation (blocks viral binding sites, coats bacteria) (phagocytosis)
• Agglutination of microbes (phagocytosis)
• Precipitation of dissolved antigens (phagocytosis)
• Activation of complement system (cell lysis)

Question 7

How do cytotoxic T cells work?

Answer 7

• Bind to infected cell
• Perforin makes holes in infected cell’s membrane
• Enzymes enters
• Infected cell is destroyed

Question 8

Immunodeficiency

Answer 8

Clinical situations where the immune system is not effective enough to protect the body against infection

Question 9

What age is immunodeficiency most common?

Answer 9

Can occur at any age, children and elderly are much more sensitive to infection

Question 10

Primary immunodeficiency

Answer 10

Caused by genetic defects in individual components of the immune system

Question 11

Secondary immunodeficiency

Answer 11

Effects of external factors

Question 12

Primary immunodeficiency

Answer 12

• Very rare
• Diagnosed in early childhood, can present in adult life
• Recurrent infection

Question 13

Secondary/acquired immunodeficiency

Answer 13

• Stress
• Surgery/burns
• Malnutrition
• Cancer (lymphoproliferative disease)
• Immunosuppressive effect of drugs (cancer therapy - lymphocytes/neutrophils)
• Irradiation
• AIDS
• Other infections e.g. measles, TB

Question 14

Nitroblue tetrazolium test

Answer 14

• Incubate neutrophils with die and creates free oxidative neutrophils, if works blue > dark
• Used for chronic granulomatous disease and other diseases of phagocyte function

Question 15

Chronic granulomatous disease

Answer 15

• Osteomyelitis (bone marrow inflammation)
• Pneumonia
• Swollen lymph nodes
• Gingivitis (inflammation of gum)
• Non-malignant granulomas
• IBD

Question 16

Complement pathway test

Answer 16

• Incubate sheep RBC and patients serum

- Complement system should active > RBC lysis

Question 17

Primary B-cell deficiencies

Answer 17

• Common variable immunodeficiency
• X-linked agammaglobulinaemia
• Autosomal recessive hyper IgM syndrome
• IgA deficiency
• IgG subclass deficiency
• Transient hypogammaglobuinaemia of infancy

Question 18

Primary T-cell deficiencies

Answer 18

• Severe Combined Immunodeficiency syndromes
• Adenosine Deaminase deficiency
• Purine nucleoside phosphorylase deficiency
• MHC class II deficiency
• Wiskott-Aldrich syndrome

Question 19

B cell defect

Answer 19

• Different degrees of loss of antibody secretion
• Recurrent bladder infection with pyogenic organisms
• Diagnosed around 1-2yrs, maternal IgG protection

Question 20

Treatment for B cell defect

Answer 20

Antibiotics, then IV IgG for life

Question 21

How serious is IgA deficiency?

Answer 21

Less serious then IgG, which is very serious

Question 22

SCID

Answer 22

Defects in B and T cells

Question 23

Treatment of SCID

Answer 23

Gene therapy or bone marrow transplantation (curative)

Question 24

T cell defect

Answer 24

More dramatic as B cells need T cell help

Question 25

Symptoms of T cell defect

Answer 25

Recurrent infection with opportunist infections, bacteria and viruses e.g. Fungi (candida), protozoa (pneumocystis)