Session 10: Immunosuppression Flashcards
What is rheumatoid arthritis?
Auto-immune multi-system disease that is fairly common.
It is initially localised to the synovium of the joins. There is proliferation of the synovium called a pannus which leads to dissolution of cartilage and bone.
Rheumatoid arthritis pathogenesis.
Three phases:
Initiation phase with non-specific inflammation.
Amplification phase with plasma cells producing rheumatoid factors and T cell activation.
Chronic inflammatory with imbalance of pro-inflammatory factors such as IL-1, IL-6, TNFalpha and anti-inflammatory.
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Clinical criteria to diagnose RA.
Morning stiffness lasting more than 1 hour
Arthritis of 3 or more joints
Arthritis of hand joints
Symmetrical arthritis
Rheumatoid nodules
Non-clinical criteria of (Ix) of RA.
Serum rheumatoid factor or Anti-CCP antibodies.
X-ray changes
X-ray changes of RA.
Soft tissue swelling
Loss of joint space
Marginal erosion
Periarticular Osteopenia
Treatment strategy of RA.
Early use of disease-modifying drugs.
Good disease control and get the RA into remission state with drugs.
Adequate dosages
Combinations of drugs
Avoidance of long-term corticosteroids.
Other common auto-immune disorders.
Systemic Lupus Erythematous
Vasculitis (SLE can cause vasculitis)
Common pathophysiology of vasculitis.
Inflammation of blood vessels.
This will cause problems in many organs supplied with vessels.
Kidneys, pulmonary haemorrhage, skin purpuric rashes.
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Treatment goals in SLE and vasculitis.
Symptomatic relief
Reduction in mortality
Prevention of organ damage
Reduction in long term morbidity
Give examples of immunosuppressants.
Corticosteroids
Methotrexate
Azathioprine
Ciclosporin
Tacrolimus
Mycophenolate mofetil
Leflunomide
Cyclophosphamide
Explain the mechanism of action of corticosteroids.
Prevention of IL-1 and IL-6 production by macrophages (pro-inflammatory)
Inhibit all stages of T-cell activation
Give examples of non-biologics
Sulphasalazine
Hydroxychloroquine
Give examples of biologics.
Anti-TNF agents
Rituximab
IL-6 inhibitors
JAK inhibitors
When is Azathioprine used?
SLE
Vasculitis (maintenance therapy for the two)
Inflammatory bowel disease
Atopic dermatitis
Bullous skin disease
Also used as a steroid sparing drug
Pharmacokinetics of azathioprine.
A prodrug converted into 6-MP which is the active metabolite.
This will then further be deactivated by TPMT and then excreted renally.
What is special about TPMT?
Highly polymorphic
What is important to test for before prescribing azathioprine?
TPMT activity
This is because the levels of TPMT will vary a lot in people.
If TPMT is low then there will be more adverse drug effects.
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ADRs of Azathioprine.
Bone marrow suppression
Increased risk of malignancy
Increased risk of infection
Increased risk of liver toxicity
Give examples of calcineurin inhibitors.
Ciclosporin
Tacrolimus
Give use of ciclosporin and tacrolimus.
Transplantation
Atopic dermatitis
Psoriasis
Why is ciclosporin and tacrolimus not often used in rheumatology.
Because it can renally toxic.
That’s why you need to check BP and eGFR regularly.
What drugs will interact with ciclosporin and tacrolimus?
CYP P450 inducers and CYP P450 inhibitors
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Mechanism of action of ciclosporin.
Active against helper T-cell and prevent production of IL-2 via calcineurin inhibition.
This is by ciclosporin binding to cyclophilin protein to form a complex.
This complex will bind to calcineurin. Calcineurin usually is supposed to cause IL-2 transcription, but ciclosporin inhibits this.