Immunodeficiency

Question 1

List the pattern recognition receptors (PRRs).

Answer 1

• Toll-like receptors (TLR’s)
• NOD-like receptoes (NLR’s)
• Rig-like receptors (RLR’s)
• C-type lectins (CLR’s)
• scavenger receptors

Question 2

What types of antimicrobial peptides are involved in the innate immune response?

Answer 2

• defensins
• cathelin
• protegrin
• granulsyin
• histatin
• secretory leukoprotease inhibitor
• probiotics

Question 3

Which cells are involved in the innate immune response?

Answer 3

• Macrophages, dendritic cells, NK cells, NK-T cells, neutrophils, eosinophils, mast cells, basophils, and epithelial cells

Question 4

What is immunodeficiency?

Answer 4

• Clinical situations where the immune system is not effective enough to protect the body against infection
• Can occur at any age.

Question 5

What might be the cause of immunodeficiency?

Answer 5

• Can be argued that infection is always the result of transient immunodeficiency.
• Usually secondary to the effects of external factors
• Some are primary immunodeficiencies caused by genetic defects in individual components of the immune system.
• The type of infection is a guide to underlying cause.
• Laboratory tests confirm.

Question 6

What are the causes of secondary immunodeficiencies?

Answer 6

• Stress (release of endogenous steroids - glucocorticoids)
• Surgery/burns
• Malnutrition
• Trauma (release of steroids)
• Cancer – especially lymphoproliferative disease
• Immunosuppressive effect of drugs inc. cancer therapy
• Lymphocytes
• Neutrophils

Question 7

What is the root cause of a primary immunodeficiency?

Answer 7

Genetic defect - i.e. lacking any protein involved in inflammation, innate/acquired immunity

Question 8

What is chronic granulomatous disease?

Answer 8

• Inability to acidify phagosome or form reactive oxygen species - leads to deep-seated bacterial infections e.g.
  
  • Osteomyelitis
  • Pneumonia
  • Swollen lymph nodes
  • Ginigivitis
  • Non-malignant granulomas
  • Inflammatory bowel disease

Question 9

What kind of infections do terminal complement pathway deficiencies make a person susceptible to?

Answer 9

Meningococcal

Question 10

What are the features of B cell deficiency?

Answer 10

• Lead to different degrees of loss of antibody secretion.
• Usually leads to recurrent bacterial infection with pyogenic organisms.
• Usually diagnosed at around 1-2 years since maternal IgG protects.
• Treat with antibiotics then iv IgG For life.
• Most are very serious
  
  • some less serious e.g IgA deficiency.

Question 11

Why are T cell deficiencies usually more dramatic than B cell deficiencies?

Answer 11

• Usually more dramatic since B cells also need T cell help.
• Symptoms are recurrent infection with opportunistic infections, bacteria, viruses,
• Fungi (candida), protozoa (pneumocystis).

Question 12

What is severe combined immunodeficiency disorder (SCID)?

Answer 12

• Defect in both B and T cells

Question 13

What are the primary T cell deficiencies?

Answer 13

• Severe Combined Immunodeficiency syndromes
• Adenosine Deaminase Deficiency
• Purine Nucleoside Phosphorylase Deficiency
• MHC Class II Deficiency
• Wiskott-Aldrich Syndrome

Question 14

What are the primary B cell deficiencies?

Answer 14

• Common Variable Immunodeficiency
• X-linked agammaglobulinaemia
• Autosomal recessive Hyper IgM syndrome
• IgA Deficiency
• IgG Subclass Deficiency
• Transient Hypogammaglobulinaemia of infancy

Question 15

What procedure can provide a cure in SCID?

Answer 15

Bone marrow transplant

Question 16

Defects in what lead to susceptibilty to pneumococcus and HSV?

Answer 16

PRRs

Question 17

Deficiencies of which cells lead to susceptibility to aspergillus, staphylococcus and CGD?

Answer 17

Macrophages and neutrophils

Question 18

Defects in which cells lead to recurrent sino-pulmonary infections?

Answer 18

B cells

Question 19

Defects in what lead to susceptibility to mycobacterium?

Answer 19

Certain cytokines