Immune System III

Question 1

In terms of the immune system - which three things are most effective at clearing extracellular pathogens?

Answer 1

Anti-bodies (secreted by B-cells)
Complement
Neutrophils (professional killers - phagocytosis)
(INTRA-cellular pathogens = T-cells)

Question 2

Name four congenital antibody deficiencies?

Answer 2

X-linked A-gammaglobulinaemia
Autosomal recessive Agammaglobulinaemia
Common variable immunodeficiency
Transient hypogammaglobulinaemia of infancy

Question 3

Name three non-congenital antibody deficiencies?

Answer 3

Enteropathy
Nephrotic syndrome - protein losing state
Rituximab - targets B-cells

Question 4

Describe neutrophils?

Answer 4

Phagocytic cells (also known as polymorphonuclear leucocytes) they are not found in normal healthy tissue. Involved in ACUTE inflammatory response and express receptors for Ig and complement

Question 5

Name the congenital neutrophil deficiency associated with a failure to migrate?

Answer 5

Leucocyte adhesion deficiency I-III (increased WCC on Ix)

Question 6

Name the congenital neutrophil deficiency associated with a failure of function?

Answer 6

Chronic granulomatous disease (can’t make superoxitive burst)

Question 7

What Mx indication is required in patients who are neutropaenic?

Answer 7

Need anti-fungal prophylaxis

Question 8

Which two particular organisms are recurrent in a patient with congenital complement deficiency?

Answer 8

Recurrent pyogenic infections of
1. Streptococci
2. HiB
Both of these are cleared via opsinisation
C5-C9 deficiency = recurrent meningococcal infection

Question 9

How may a patient who is T-cell deficient present?

Answer 9

Chronic and reoccurring viral and protozoal infection

Question 10

What five features are included within severe combined immunodeficiency?

Answer 10

1. Impaired cytokine signalling
2. Increased apoptosis
3. Impaired VJD recombination
4. Impaired CD3 subunit
5. Impaired Ca2+ signalling

Question 11

Why might a patient be at increased pre-disposition to getting a mycobateria/salmonella infection?

Answer 11

IL-12 = Th1 inducer - it produces IFN-Y (macrophage activation) it conveys immunity against mycobateria infections

Question 12

Describe herpes-simplex encephalitis?

Answer 12

HSV.1 - majority of cases
Syx - drowsiness/confusion/personality changes
Increased WCC in CSF withOUT pyogenic bacteria
Some cases = defect in TLR3//UNC9313//TRAF.3//TBK.1

Question 13

Loss of central and peripheral tolerance can be due to?

Answer 13

AIRE (organ specific immunity) - central

IPEX syndrome - peripheral

Question 14

Describe hereditary periodic fever syndromes (immunodeficiency)?

Answer 14

Self-limited responses (episodes) of fever every 4 weeks
Associated with joint pain, abdo pain and rashes
Unlike most AI diseases (adaptive - antibody mediated) - is caused by INNATE system (inflammasome)
Defects in pyrin cytokines (PST//PIP.1)

Question 15

Name three recessive and one dominant hereditary periodic fever syndrome?

Answer 15

1. Familial Mediterranean fever
2. Pyogenic sterile artheritis pyoderma gangrenosum acne
3. Hyperimmunoglobulin. D syndrome
   Dominant = TNF-receptor 1 associated

Question 16

Describe autoimmune lymphoproliferative syndrome?

Answer 16

Cervical lymphadenopathy
Hepatosplenomegaly
Apoptosis defect (Fas.Fas.L)
Activated immune cells can’t be terminated and therefore increased lymphoma risk

Question 17

Describe two clinical and three investigative findings in a patient with haemophagocytic lymphocytosis?

Answer 17

Fever and splenomegaly
Cytopaenia and Hb<90 and Platlets<100
CD8 T-cell is no longer able to terminate macrophages

Question 18

Describe haemolytic uraemic syndrome (incl. three features)?

Answer 18

1. Haemolytic anaemia
2. AKI
3. Decreased platelets
   Affects children
   Mutations of complement - Factor H//Factor I// MCP (complement reg protein)

Question 19

Describe pulmonary alveolar proteinosis and which condition is it commonly associated with?

Answer 19

Impairment of surfactant homeostasis (produced by T2 pneumocytes) = non-infectious respiratory failure.
GM-CSF is required to activate macrophages which will help uptake and catabolise surfactant - therefore mutations in GM-CSF = aggregation of surfactant
Associated with myeloid leukaemia