Pharmacological aspects of Immunology Flashcards
What are the NSAIDs groups?
(6)
- Aspirin
- Propionic acid derivatives - e.g. ibuprofen, naproxen
- Arylalkanoic acids – e. g indometacin, diclofenac
- Oxicams - e.g. piroxicam
- Fenamic acids - e.g. mefanamic acid
- Butazones - e.g. phenylbutazon
Explain the Eicosanoid pathways
- what are their end products and their clinical relevance? (4)
- Leukotrienes: bronchial constriction
- Thromboxanes: platelet aggregation, vasoconstriction
- Prostaglandins: bronchial tone, vascular tone, hyperalgia
- Prostcyclins: vasodilation

What effect does NSAID’s have on the Eicosanoid pathway
- NSAID’s are non-specific inhibitors of the cyclooxygenase pathway
- this irreversibly binds the enzymes to prevent prostaglandin synthesis
- therefore the tissue-specific synthases are not produced

What is the mechanism of action of NSAIDs?
(3)
- All inhibit cyclo-oxygenase
- Three isoforms
-
COX-1 - Constitutive expression – all tissues
- Stomach, Kidney, Platelets, Vascular endothelium
- Inhibition → anti-platelet activity, also side effects
-
COX-2 – Induced in inflammation (IL-1)
- Injury, infection, neoplasia
- Inhibition → analgesia and anti-inflammatory actions
-
COX-3 – CNS only?
- May be relevant to paracetamol
-
COX-1 - Constitutive expression – all tissues
What are the indications for NSAID therapy?
- Short-term management of pain (and fever)
As mild analgesics (orally and topically)
- mechanical pain of all types
- minor trauma
- headaches, dental pain
- dysmenorrhoea
As potent analgesics (orally, parenterally, rectally)
- peri-operative pain
- ureteric colic
Where is NSAID useful as an anti-inflammatory agent?
- Gout
- Inflammatory arthriitis: ankylosing spondylitis, rheumatoid arthritis
What are the indications for Aspirin?
- why might the use be limited?
- Limited in use for pain and inflammation limited by
- GI toxicity
- Tinnitus – mechanism obscure, usually reversible
- Reye’s syndrome (fulminant hepatic failure in children)
- Mainly used for its Anti-platelet effect
- Primary and secondary prevention eg stroke and MI
- Treatment of acute MI and stroke
Explain how NSAID produces GI toxicity (3)
- what are the presenting effects?
- In the GI tract prostaglandins E2 and I2
- Decrease acid production
- Increase mucus production
- Increase blood supply
- as NSAID’s inhibit this, all the above is reversed
- NSAID inhibition in stomach and duodenum
- Irritation
- Ulcers (gastric 15-30%, duodenal 10%)
- Bleeding
- Similar effect in the colon
- Colitis – esp with local preps e.g. rectal diclofenac
What is the risk of NSAID GI toxicity
- Upper GI bleeding
- Relative Risk 4.7 all users
- Azapropazone = 23.4
- Piroxicam = 18.0
- Small differences between others…
- Biggest risk factor for GI bleed = previous GI bleed
- Age
- Chronic disease (e.g.rheumatoid disease)
- Steroids
Explain how NSAIDs cause nephrotoxicity
- contraindications to avoid this
- Primarily related to changes in glomerular blood flow
- Decreased glomerular filtration rate
- Sodium retention
- Hyperkalaemia
- Papillary necrosis
- Acute renal failure 0.5-1%
- Avoid or dose adjust in renal failure
- Avoid in patients likely to develop renal failure
What is the relationship between asthma and Aspirin?
- About 10% of asthmatics experience bronchospasm following NSAID
- perhaps because of arachidonic acid is shunted down the 5LPO pathway when COX is inhibited so more leukotrienes are produced
- leukotrienes cause bronchial constriction
How can NSAID toxicity be prevented?
(4)
- Is an NSAID the answer (paracetamol, opioids, COX2 inhibitor, non-pharmacological?)
- Consider risk factors eg age, renal impairment, previous peptic ulcer disease
- Avoid or dose adjust in renal impairment
- Consider co-administration of gastroprotection with proton pump inhibitor
How is Paracetamol metabolised?
- Phase 1 oxidation reaction (induced by enzyme inducers e.g alcohol)
- NAPQI
- Phase 2 conjugation reaction (following phase 1)
- NAPQI-glutathione –> excreted
- these pathways can easily be oversaturated leading to overdose after a few extra pills
- Direct Phase 2 conjugation
- paracetamol sulphate and glucuronide –> excreted

What is the treatment for paracetamol overdose?
-
N-acetylcysteine (glutathione precursor) used in paracetamol poisoning
- enables NAPQI to be harmlessly removed

What are Selective COX-2 Inhibitors?
- what are they used for
- risk/indication
- Selective inhibition of COX-2 in vitro and in vivo
- Anti-inflammatory and analgesic in humans
- Objective evidence of selectivity (GI, platelets) at > anti-inflammatory doses
- Comparable efficacy (not superior) to non-selective NSAIDs in
- Acute pain
- Dysmenorrhoea
- Inflammatory joint disease
- Controversy due to apparent increased risk of MI – but may have been a result of an absence of antiplatelet effect
- Currently only recommended in high-risk patients and after a cardiovascular risk assessment
What are the side effects of COX-2 Inhibitors?
- has GI-side effects but has a relatively lower risk compared to NSAIDs

What are corticosteroids?
- example
- action (6)
Cortisol (hydrocortisone) – predominant endogenous glucocorticoid
- Carbohydrate and protein metabolism
- Fluid and electrolyte balance (mineralocorticoid effects)
- Lipid metabolism
- Psychological effects
- Bone metabolism
- Profound modulator of immune response
What is the biological effect o corticosteroids?
- Steroids reduce immune activation by altering gene expression in numerous cell types,
- including T cells, B cells and cells of the innate immune system.
- Their onset of action is delayed and they must be taken regularly

What are the immunomodulatory effects of steroids?
- cell trafficking (2)
- cell function (7)
- don’t effect (2)
- Cell trafficking
- Lymphopenia, monocytopenia (redistribution)
- Neutrophilia and impaired phagocyte migration
- Cell function
- T cell hyporesponsiveness
- Inhibited B cell maturation
- Decreased IL1, IL6 and TNFa production (monocytes)
- Widespread inhibition of Th1 and Th2 cytokines
- Inhibition of COX - prostaglandins
- Impaired phagocyte killing
- ↓collagenases, elastases etc
- Don’t effect
- Immunoglobulin levels
- Complement
What is the clinical use/ indication cor corticosteroids?
- types of preparations
- To suppress inflammation of all kinds, particularly in acute disease but also in maintenance therapy
- Asthma, Crohn’s / UC, Eczema, Multiple sclerosis, Sarcoid, allergy, rheumatoid arthritis, systemic lupus erythematosus etc etc
-
Replacement therapy in hypoadrenalism
- __hydrocortisone used
- Myriad preparations, and also routes
- Systemic (oral and parenteral)
- Topical (skin, joint injections, inhaled, enteric-coated, rectal)
What are the five key Corticosteroid drugs to remember?
- what are their potency
- lipid solubility
- systemic vs topical use

What are the Early side effects of steroid therapy?
(4)
- Weight gain
- Glucose intolerance
- Mood change
- Suppression of ACTH release
What are the Late side effects of steroid therapy?
(7)
- Proximal muscle weakness
- Osteoporosis
- Skin changes
- Body shape changes
- Hypertension
- Cataracts
- Adrenal suppression
How do corticosteroids affect the adrenal system?
- How is this managed?
- High-dose exogenous corticosteroids suppress endogenous production within 1 week
- __clinical effects not seen until later
- After prolonged therapy adrenal cortex begins to atrophy and endogenous production takes some time to recover upon cessation
- Abrupt withdrawal below replacement dose reduces the ability to deal with physiological stress – eg infection – and may precipitate an adrenal crisis
- Steroid warning card
- Tail dose slowly
- Increase dose during acute illness and prior to surgery
Link between infection and corticosteroid use
- Risk is related to cumulative dose
- Phagocytic defects (risk occurs early on)
- Bacterial infection – S. aureus, enteric bacteria etc
- Fungal infection – candida, aspergillus
- candida using inhalers - rinse mouth after use
- Cell-mediated defects (risk occurs later on)
- Intracellular pathogens
- TB
- Varicella
- Listeria
- Pneumocystis
What are Disease-modifying anti-rheumatic drugs (DMARDS)?
- diverse group of drugs that target the immune system
- Derive name from use in rheumatoid arthritis, but also used in
-
transplantation and myriad other autoimmune and inflammatory disorders
- __chronic urticaria, eczma, psoriasis
- also sometimes (in higher doses) for cancer chemotherapy
-
transplantation and myriad other autoimmune and inflammatory disorders
How are Disease-modifying anti-rheumatic drugs (DMARDS) distinguished from other drug classes
- NSAID
- Steroids
- Biologics
- NSAIDS: despite name, not disease-modifying
- Steroids: the idea of DMARDS is that they’re ‘steroid-sparing’
- Biologics: newer class of drugs resembling naturally-occurring molecules
Give examples of Disease-modifying anti-rheumatic drugs (DMARDS)
(3)
- what are their actions, indications
-
Methotrexate: competitive inhibitor of dihydrofolate reductase (DHR)
- anti-folate action which is needed for purine synthesis in DNA
- reduces T cell activity
- used in Rheumatoid arthritis, Psoriasis, Chrons disease
-
Azathioprine: Inhibits thiopurine S methyltransferase (TPMT)
- also inhibits purine synthesis
- similar indications to methotrexate, more widely used in transplantation
-
Ciclosporin: Inhibits calcineurin which in turn reduce T lymphocyte activity
- similar indications to aza/metho
- used in more dermatology and transplantation
What is Ciclosporin?
- action
- indication
- toxicity
- Inhibits calcineurin, which in turn reduces T lymphocyte activity
Main indications
- more widely in dermatology and transplantation
- Rheumatoid arthritis, Psoriasis, Crohns disease
Main toxicities
- Hepatotoxicity
- Nephrotoxicity
- Gum hyperplasia
- Hirsutism
NOTE tacrolimus (newer formulation) is easier to take and tolerate, and available for topical use (esp eczema)
What is Azathioprine?
- action
- indication
- toxicity
- Inhibits thiopurine S methyltransferase (TPMT), also inhibits purine synthesis
- Folate needed for purine synthesis in DNA
- This reduces T cell activity
Main indications
- more widely in transplantation
- Rheumatoid arthritis, Psoriasis, Crohn’s disease
Main toxicities
- GI upset very common when starting
- Hepatotoxicity
- Leucopenia
- Pulmonary fibrosis
- Teratogenic
What is Methotrexate?
- action (4)
- indication
- toxicity
- Competitive inhibitor of dihydrofolate reductase (DHR), therefore anti-folate action
- Folate needed for purine synthesis in DNA
- This reduces T cell activity, and also (in higher doses) tumour synthesis
- Increases adenosine level (anti-inflammatory)
- Reduces the production of damaging polyamines
- Induces apoptosis of activated CD4+ and CD8+ T-cells
Main indications
- Rheumatoid arthritis
- Psoriasis
- Crohns disease
Main toxicities
- Hepatotoxicity
- Leucopenia
- Pulmonary fibrosis
- Teratogenic
NOTE weekly dosing; errors have caused major toxicity
What are therapies for rheumatoid arthritis (RA)
- most effective?
-
Anti-inflammatory drugs: Symptoms relief
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Steroidal anti-inflammatory drugs (glucocorticoids)
-
Disease-modifying anti-rheumatic drugs (DMARDs): Slow the clinical and radiographic progression of RA
- Synthetic DMARDs: MTX, sulfasalazine, hydroxychloroquine, leflunomide
- Targeted synthetic DMARDs: JAK inhibitors- tofacitinib, baricitinib
- Biologic agents (biologicals): TNF-blockers (most effective)
- Drugs targeting IL-1, IL-6 , B-cells and T-cells
Give more detail on the clinical use and action of Methotrexate
- “Anchor drug” in combination therapies
- Reduces inflammation quickly and keeps it under tight control
- Reduces the risk of death from cardiovascular disease in people with RA
- Taking supplements of folic acid reduces side-effects caused by folic acid depletion
What are the adverse effects of synthetic DMARDs
- what is a synthetic DMARD
- Methotrexate, Hydroxychloroquine, Leflunomide are synthetic DMARDs
- Hydroxychloroquine: accumulation of a drug in the eye –> retinopathy
- Leflunomide- hypertension
- Methotrexate, Hydroxychloroquine, Leflunomide are synthetic DMARDs
- Nausea, Loss of appetite
- Diarrhoea
- Rash, allergic reactions
- Headache
- Hair loss
- Risk of infections (pneumonia)
- Hepatotoxicity (metabolism), Nephrotoxicity (route of elimination)
Give examples of targeted synthetic DMARDs (2)
- action
- indication
used in moderate-to-severe active RA in patients who have had an inadequate response to, or are intolerant to one or more DMARDs (as monotherapy or in combination with MTX): more effective
-
Tofacitinib
- selectively inhibits the JAK1 and JAK3
- also used in psoriatic arthritis and UC
-
Baricitinib
- selectively and reversibly inhibits JAK1 and JAK2

What are adverse effects of targeted synthetic DMARDs?
-
Tofacitinib
- Anaemia, cough,
- diarrhoea,
- fatigue, fever,
- gastrointestinal discomfort, increased risk of infection
-
Baricitinib
- Dyslipidaemia, herpes zoster,
- increased risk of infection,
- nausea,
- oropharyngeal pain,
- thrombocytosis
What are biologics?
- give an example of biologics treatment
- therapeutic treatment derived or synthesised from biological sources
- Anti-TNF-alpha antibody: in treating Rheumatoid Arthritis

What is the role of TNF in the inflammatory cascade of Rheumatoid Arthritis?
- TNF hyperactivity
- results in high-levels IL-1
- TNF blockers reduces these effects

What are the targets of biologic agents in RA?

When are biological therapies indicated?
- Patient has failed to respond to treatment with at least two standard (synthetic) DMARDs,
- one of which must be MTX (unless the patient cannot take MTX for medical reason)
- Patient’s RA _disease activity score (DAS 28) is measured as 5.1 o_r over, on two occasions, one month apart
What are the currently licensed biologics for the treatment of RA in the UK?
(4)
- TNF-blockers: infliximab, etanercept, adalimumab, golimumab, certolizumab pegol
- Monoclonal antibody against B cells: rituximab
- T cell co-stimulation inhibitor: abatacept
- Monoclonal antibodies against IL-6R: tocilizumab, sarilumab
What are the TNF-blockers? (5)
- how are they best applied
- Infliximab – partially humanized mouse monoclonal anti-hTNF-a antibody
- Etanercept – soluble TNF receptor dimer
- Adalimumab – human IgG1 monoclonal anti-TNF-a antibody
- Golimumab – human IgG1 monoclonal anti-TNF-a antibody
- Certolizumab pegol – PEGylated anti-TNF-a monoclonal antibody fragment
- combined with MTX, they give excellent joint protection
What is Infliximab
- mechanism
- used in?
- NICE
- Partially humanized mouse monoclonal anti-human TNF-a antibody
- chimeric antibody
- Neutralizes free, membrane and receptor-bound TNF-a → antibody-dependent cell-mediated cytotoxicity (ADCC)
- Treats RA and
- Also used for the treatment of Crohn’s disease, ulcerative colitis, plaque psoriasis, ankylosing spondylitis
- NICE only approves infliximab, if combined with MTX

What is Etanercept
- mechanism
- used in?
- Extracellular domain of the hu p75 TNFR fused with the Fc domain of hu IgG1
- Binds free and membrane-bound TNF, reducing the accessible TNF in Rheumatoid Arthritis → ADCC
- it’s a soluble TNF receptor dimer
- Used in RA
- Also used for the treatment of juvenile idiopathic arthritis, plaque psoriasis, psoriatic arthritis, ankylosing spondylitis

What are the two fully human anti-TNF-alpha mAbs?
- used in?
Adalimumab
- treating RA
- Also used in juvenile idiopathic arthritis, plaque psoriasis, psoriatic arthritis, ankylosing spondylitis, Crohn’s disease
Golimumab
- treating RA
- In combination with MTX
- Also used in psoriatic arthritis, ankylosing spondylitis
- Longer half-life
What is Certolizumab pegol?
- mechanism
- used in?
- what is peg?
- PEGylated Fab’ fragment of humanized anti-TNF-a mAb – no Fc portion
- used to treat RA
- Also used for the treatment of Chron’s disease
Polyethylene glycol: When covalently attached to drugs, it reduces antigenicity/ immunogenicity prolongs the circulatory time of the drug
What is considerations made before anti-TNF therapy?
- what are the side effects?
- course of treatment
- Patients screened before starting treatment to exclude an increased risk of side effects, in particular for
- a past history of tuberculosis (TB),
- multiple sclerosis,
- recurrent infection,
- leg ulcers
- and a past history of cancer
- Chest X-ray to be taken to exclude signs of previous TB and to exclude signs of heart failure
- Increased risk of infections, reactivation of TB
- cancer can be worsened
- Live vaccines, against e.g. yellow fever or polio, should be avoided
- Anti-TNF therapy can be administered for as long as 10 years.
- Patients can stay on the drug for as long as they continue to respond well to it
What is Rituximab
- mechanism
- used in
- partially humanized anti-CD20 mAb
- Rituximab opsonized B-cells are attacked and killed by three mechanisms:
- 1)Complement mediated cytotoxicity
- 2-3) Antibody-dependent cell-mediated cytotoxicity (ADCC) – FcgR or CR mediated opsonic phagocytosis
- 4) Apoptosis of B cell
- used to treat RA and in the treatment of SLE

What is Abatacept
- mechanism
- used in?
- CTLA-4/ hu IgG1 soluble receptor fusion protein
- acts as a T-cell co-stimulation inhibitor
- Competitive inhibitor of CD28
- Increases threshold for T-cell activation
- Suppresses the proliferation of synovial recirculating T cells
- Reduces the level of inflammatory mediators
- used in treating RA

What are two IL-6R inhibitors?
- mechanism
- used in?
-
Tocilizumab: humanized anti-IL-6 receptor monoclonal antibody
- Also used in systemic juvenile idiopathic arthritis
- Intravenous infusion 8 mg/kg of body weight
-
Sarilumab: fully human monoclonal antibody against IL-6Ra
- 200 mg once every two weeks, administered as a subcutaneous injection
- used in patients with critical covid-19 infection

What is Anakinra?
- mechanism
- used in
- Recombinant IL-1ra- acts an IL-1R antagonist
- Differs from native human IL-1ra: it has the addition of a single methionine residue at its amino terminus
- In RA:
- Reduces bone erosion
- Decreases osteoclast production
- Blocks IL-1-induced MMP release from synovial cells
- Not used in the UK to treat RA, but licensed in the US

What are the adverse effects of biological therapies?
- contraindications?
- Increased risk of infections:
- Upper respiratory tract infections (nasopharyngitis)
- Pneumonia
- Urinary tract infections
- It is recommended to receive influenza and pneumococcal vaccines before embarking on biological therapy
- Avoid live vaccines
- Nausea
- Headache
- Hypertension
- Allergic reactions
Contraindicated in pregnancy and while breastfeeding (rituximab, tocilizumab, sarilumab, abatacept, anakinra)
Review the biologics used in Rheumatoid Arthritis

