Drugs and the Immune System II Flashcards

1
Q

How do disease modifying drugs function?

A

Alter underlying disease rather than treating symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name 2 types of DMDs

A
  1. Conventional DMDs (slow acting)

2. Biological therapies (fast acting)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name 3 conventional DMDs

A
  1. Cyclosporine
  2. Thiopurines
  3. Methotrexate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name 2 examples of biological therapies

A
  1. Anti-TNF drugs

2. Drugs which target cytokines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe how biological therapies are usually used

A
  • In combination with a conventional DMD
  • Given to people who do not respond to conventional DMDs
  • Given to people who have side-effects with conventional DMDs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe cyclosporine A as a chemical

A

Cyclic undeca-peptide isolated from T. inflatum (fungus found in soil)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name 2 major uses for cyclosporine A

A
  1. Organ transplant

2. Autoimmune diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Name 4 autoimmune diseases

A
  1. Rheumatoid arthritis
  2. Posterior uveitis
  3. Myasthenia gravis
  4. Crohn’s disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the chain of events which causes release of IL-2 from activated T cells

A
  • APC activates T cells by variety of receptors including T Cell Receptors (TCR)
  • Activation produces calcineurin (CaN) which catalyses the dephosphorylation of NFAT
  • NFAT allows for transcription factors, including IL-2, to be produced
  • Transcription factors cause proliferation of T lymphocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do cyclosporine drugs influence the chain of events which causes the release of IL-2?

A
  • Cyclosporine acts as a CaN inhibitor
  • Reduction of IL-2 produced
  • Reduced proliferation of T lymphocytes so suppression of the immune response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe 2 types of actions by cyclosporine

A
  1. Antibody mediated suppression

2. Cell mediated suppression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the major side effect of cyclosporine?

A

Nephrotoxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name 3 types of nephrotoxicity which can be caused by cyclosporine

A
  1. Acute toxicity
  2. Chronic toxicity
  3. Glomerular filtration affected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What 2 components of a renal biopsy would suggest progressive nephrotoxicity in cyclosporine use?

A
  1. Arteriolar changes

2. Strips of fibrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name 4 minor side effects of cyclosporine

A
  1. Mild hepatotoxicity
  2. Lethargy
  3. Hypertrophy
  4. Diarrhoea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do thiopurines function?

A

Purine metabolite antagonists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Name 2 uses of thiopurines

A
  1. Anti-cancer agents

2. Immunosuppressive agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Name a type of thiopurine drug

A

Azathioprine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are thiopurines metabolised?

A

(S)-methyltransferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe how purines are synthesised

A
  • Adenine / Guanine in DNA and RNA synthesis

- Adenosine found in cAMP and principle energy source in ATP and ADP

21
Q

Describe how purines have a major role in inflammation

A
  • Extracellular signalling pathways
  • Extracellular levels increase during inflammation and act on specific purinergic receptors
  • Activation of adenosine receptors mediates cytoprotection in response to inflammation
  • Activation of ATP-sensitive P2X₇ receptor triggers pro-inflammatory signalling
22
Q

Name 2 adenosine receptor type which have anti-inflammatory roles

A
  1. A2A

2. A2B

23
Q

Describe the mechanism of action for azathioprine

A
  • Metabolised to 6-MP to become active via HPRT catalysed reaction
  • 6-MP converted to TIMP and then meTIMP via TPMT catalysed reaction which is an inhibitor of de novo purine biosynthesis
  • Any TIMP which escapes catabolism is converted to TGMP and then meTGMP via TPMT catalysed reaction
  • Any TGMP which escapes catabolism is converted to thio-dGTP which is cytotoxic
24
Q

What does TPMT stand for?

A

Thiopurine S methyltransferase

25
Q

What does HPRT stand for?

A

Hypoxanthine-guanine phosphoribosyltransferase

26
Q

Name 2 side effects of thiopurines

A
  1. Therapy-related cancer (mainly skin)

2. Methylated DNA 6-TG is cytotoxic

27
Q

How does methotrexate function?

A

Anti-metabolite of folic acid by competitive inhibition

28
Q

What is the DHFR enzyme?

A

Dihydrofolic acid reductase

29
Q

Describe the importance of the DHFR enzyme

A
  • Catalyses dihydrofolate to tetrahydrofolate (active form)
  • Necessary for de novo synthesis of nucleoside thymidine (DNA synthesis)
  • Necessary for purine base synthesis (adenine and guanine)
30
Q

Describe how methotrexate is a useful treatment in cancer

A
  • Inhibits all purine synthesis
  • Acts specifically during DNA and RNA synthesis
  • Cytotoxic during the S-phase of the cell cycle
  • Greater toxic effect on rapidly dividing cells than normal cells
31
Q

Describe the possible anti-inflammatory action of methotrexate

A
  • Inhibition of enzymes involved in purine metabolism
  • Inhibits trans-methylation reactions required for inflammation (no clinical evidence)
  • Induction of adenosine release (inflammation inhibitor)
  • Suppression of T cell activation
32
Q

Describe how methotrexate stimulates adenosine release

A
  • MTX is polyglutamated in the cell
  • MTXglu inhibits AICART
  • Increased levels of AICAR which inhibits adenosine deaminase
  • Enhanced levels of adenosine released
  • Binds to adenosine receptor A2 to reduce inflammation
33
Q

Describe 4 most common side effects when using methotrexate

A
  1. Low WBC count
  2. Highly teratogenic
  3. Effects on CNS e.g. myelopathies
  4. Nausea
34
Q

Name a rare side effect of methotrexate

A

Pulmonary fibrosis

35
Q

Name 2 drug interactions of methotrexate

A
  1. Penicillin (decrease elimination of MTX)

2. Carbamazepine (increase neurotoxicity of MTX)

36
Q

What form of cytokine is used as a novel immunoregulator?

A

Recombinant forms

37
Q

Name 3 cytokine products licensed in the UK

A
  1. Aldesleukin (recombinant IL-2)
  2. Adalimumab / Infliximab (TNF-α antagonist)
  3. Ankinra (IL-1R antagonist)
38
Q

Describe the mechanism of action of aldesleukin

A

Stimulation of cytotoxic CD8 and NK cells in response to antigen

39
Q

What is aldesleukin licenced for?

A

Metastatic renal cell carcinoma

40
Q

What 3 factors may exclude patients with metastatic renal cell carcinoma from receiving aldesleukin as treatment?

A
  1. Performance status of Eastern Co-Operative Oncology Group over 1
  2. More than one organ with metastatic disease sites
  3. Period of 23 months between initial diagnosis and date of evaluation of treatment
41
Q

How is aldesleukin usually administered?

A

Subcutaneous injection

42
Q

Why is aldesleukin not administered IV?

A

Increased risk of capillary leak syndrome, which can cause pulmonary oedema and hypotension

43
Q

Name 4 uses of TNF-α antagonists

A
  1. Rheumatic disease
  2. Inflammatory bowel disease
  3. Plaque psoriasis
  4. Psoriatic arthritis
44
Q

Name the major side effect of TNF-α antagonist drugs

A

Associated with infections, sometimes severe, including tuberculosis and septicaemia

45
Q

Name 4 minor side effects of TNF-α antagonist drugs

A
  1. Nausea
  2. Abdominal pain
  3. Fever / headache
  4. Hypersensitivity reactions
46
Q

What is anakinra licenced for?

A

Treatment of rheumatoid arthritis which has not responded to methotrexate alone

47
Q

What is a common side effect of anakinra?

A

Neutropenia

48
Q

Describe the mechanism of action of anakinra

A

Recombinant form of IL-1 receptor antagonist inhibiting IL-1 activity by competitive inhibition