Immune Modulation Flashcards
Types of Immune Modulation
Vaccination
Replacement
Suppression
Sensitisation
Vaccination mechanism
Memory lymphocyte production → rapid polyclonal expansion of adaptive immune response
Active vs Passive Vaccination
Active - your own body produces response - long-term protection
Passive - pre-formed antibodies given - around 3 weeks
What are Dendritic cell vaccines
Summarise Paediatric vaccination schedule
Regular adult vaccinations
Key travel vaccines
2 non-travel vaccines that are given based on risk
4 Types of Vaccine
Live attenuated
Inactivated/component/toxoid
Conjugate
DNA/RNA
What is a live attenuated vaccine?
Give examples
Modified pathogen to limit pathogenesis
E.g. MMR-VBOY
Inactivated vaccine examples
Influenza (quadrivalent),
Polio (Salk),
Cholera,
Bubonic plague,
Hep A,
Rabies, Pertussis
Component vaccine examples
Hep B [HbS antigen],
HPV [Capsid],
Influenza recombinant quadrivalent) [haemagglutinin, neuraminidase]
Toxoid vaccine examples
Diptheria
Tetanus
Conjugate vaccine examples
NHS
Tetanus
DNA/RNA vaccine examples
SARS-CoV-2
What does an adjuvant do in vaccination?
Increases immune response without altering specificity
2 Main types of adjuvant
Depot
Stimulatory
How does a depot adjuvant work?
Slows antigen release → increased exposure to antigen → promotes immune response
Depot adjuvant example
ALUM
How does a stimulatory adjuvant work?
Mimics the action of PAMPs on TLR and PRRs → increased receptor activation → boosted immune response
Stimulatory adjuvant example
CpG
Types of Immune Replacement
Haematopoietic SCT
Ab replacement - specific/unspecific
Adoptive T cell transfer
Types of adoptive T cell transfer
Virus specific T cells
TIL T cell therapy
TCR
CAR-T cell therapy
Describe TIL T cell therapy
TILs from tumour → expanded with IL2 → infused into lymphoid depleted patient → destroys cancer cells
Describe CAR-T cell therapy
Chimeric receptor targets CD19 → greater immune response to tumour than TCR therapy
for ALL, NHL
1/2 life of normal human IVIG
18 days
Examples of recombinant cytokines
IL-2
IFN-alpha
IFN-beta
IFN-gamma
Recomobinant IL-2 uses
Renal cancer
(IL-2 2 kidneys)
IFN-alpha uses
Viruses - Hep B & C (ABC)
Cancer
IFN-beta uses
Relapsing remitting MS
IFN-gamma uses
CGD
Immune Checkpoint blockade drugs
Ipilimumab
Pembrolizumab
Nivolumab
Immune checkpoint blockade indications
Advanced melanoma
Metastatic renal cancer
Ipilimumab mechanism
Normally: CD80 and CD86 (APCs) interact with CTLA4 (inhibitory) and CD28 (stimulatory)
CTLA4 inhibitor → blocks CTLA4, all APC interactions now through CD28 → boosted T cell response
Pembrolizumab/nivolumab mechanism
PD-1 (prevent death-1) blocker monoclonal antibody
Normally, cancer cells bind PDL-1 to Treg PD-1 → prevents Treg cell killing of tumour cell
PD-1 blockade prevents binding of PDL-1 to PD-1 → enabling Treg cell killing of tumour cell
3 signals in naive T cell priming
Activation: MHC-TCR interaction
Survival: CD86/B7-CD28 interaction
Differentiation: cytokines
What are the adverse effects of immunosuppressive drugs?
Infusion reaction (IgE)
Injection reaction
Acute infection
Chronic infection
Malignancy
Autoimmunity
How do you manage acute infection due to immunosuppression?
Prevention: non-live vaccination
Mx: stop immunosuppression,
ABx - cover for atypicals
What chronic infections can be seen with immunosuppression?
TB
HIV
Hep B, C
JCV
TB during immunosuppression Mx
Ix: check exposure + CXR
Mx: prophylaxis/treat as needed
HIV and immunosuppression
Check for HIV before treatment
How to manage viral hep during immunosuppression?
HBcAb and HCAb before treatment
If positive → further Ix
What is John Cunningham virus?
Polyoma virus that can reactivate → infecting and destroying oligodendrocytes → Progressive Multifocal Leukoencephalopathy (PML)
Prednisolone mechanism of immunosuppression
- Phospholipase A2 inhibition → reduced prostaglanding synthesis → reduced inflammation
- Inhibits phagocyte tracking, phagocytosis and release of proteolytic enzymes → decreased phagocyte activity
- Promotes lymphocyte apoptosis, splenic sequestration (CD4>8>B), ↓ antibody productions and blocks cytokine gene expression → lymphopenia
Corticosteroid SEs
Metabolic: Cushing’s, diabetes, osteoporosis, adrenal suppression
Infection
Eyes: cataracts, glaucoma
GI: peptic ulcers, pancreatitis
Avascular necrosis
Antiproliferative agents
Cyclophosphamide
Mycophenylate mofetil
Azathioprine
Methotrexate
Antiproliferative agents SE
Bone marrow suppression
Cyclophosphamide mechanism of action
Alkylates guanine in DNA → DNA damage → no cell replication
B>T cells
Cyclophosphamide key SE
Haemorrhagic cystitis
Mycophenylate Mofetil mechanism
Anti-metabolite
Blocks I-5’-MPHDH → prevents de novo guanine synthesis → stops replication
T>B cell
Mycophenylate Mofetil key SE
Progressive Multifocal Leukoencephalopathy (JC virus)
Azathioprine mechanism of action
Anti-metabolite
Pro-drug
Metabolised in liver to 6-metacarptopurine → prevents de novo purine synthesis → prevents DNA replication
What to check for before giving azathioprine and why?
TPMT mutation - can lead to bone marrow suppression with azathioprine
Methotrexate Mechanism of action
Anti-folate
Inhibits DHFR → inhibits DNA synthesis
Methotrexate SEs
F2oL2ate
Foetus - teratogenic
Folate deficiency
Lung - pneumonitis, pulmonary fibrosis
Liver - hepatotoxic
Plasmapharesis what is it and indications
Removal of pathological antibody
Indicated in severe Type II HS disease e.g. Goodpasture’s
Key SEs of plasma pharesis
Rebound antibody production
Anaphylaxis
Inhibitors of Cell Signalling
Calcineurin inhibitors - Tacrolimus, Cyclosporin
mTor (IL-2 pathway) inhibitors - Sirolimus, Rapamycin
Tofacitinib - JAK1/3 inhibitor
Apremilast - PDE4 inhibitor
Mechanism of Tacrolimus and Cyclosporin
Inhibit calcineurin → decreased IL-2 expression → reduced T-cell proliferation
Side effects of calcineurin inhibitors
Nephrotoxic, neurotoxic, hypertension
Tacrolimus - diabetogenic
Cyclosporin - Gingival hyperplasia
Sirolimus (Rapamycin) mechanism of action
mToR inhibition → T cell proliferation inhibition via IL-2 pathway
Sirolimus indication
Transplantation
Sirolimus SEs
Hypertension, less nephrotoxic than calcineurin inhibitors
Tofacitinib mechanism
Inhibits JAK-STAT signalling → inhibits production of inflammatory molecules by influencing gene transcription
Apremilast mechanism
PDE4 inhibitor → increases cAMP through protien kinase A pathway → modulates cytokine production
Apremilast indication
Psoriasis, psoriatic arthritis
Main agents against cell surface antigens
Rabbit anti-thymocyte globulin
Basiliximab
Abatacept
Rituximab
Vedolizumab
Anti-thymocyte globulin actions
Lymphocyte depletion
Inhibition of T cell migration and activation
Anti-thymocyte globulin uses
Allograft rejection
Anti-thymocyte globulin SEs
Infusion reactions, leukopenia
Basiliximab mechanism of action
Blocks IL-2 induced signalling and T cell proliferation
Basiliximab Indication
Allograft rejection (prophylaxis)
Abatacept mechanism of action
Blocks CD80 and CD86 → reduced co-stimulation of T cells by CD28
Abatacept indication
Rheumatoid arthritis
Abatacept main caution
Malignancy
Rituximab mechanism of action
anti-CD20 → depletes mature B cells
Rituximab indication
lymphoma, rheumatoid arthritis, SLE
Rituximab SEs
Infusion reactions, infections (PML), exacerbation CV disease
Vedolizumab mechanism of action
Anti-alpha-4-beta-7 integrin → inhibits binding to MadCAM1 → stops leukocyte binding to endothelium and extravasation to tissue
Natalizumab antibody and indication
anti-alph-4-beta-1 integrin
MS and Crohn’s
Cytokines and receptor targets for immunomodulatory agents
Anti-TNF alpha drugs
CAIG
Certolizumab
Adalimumab
Infliximab
Golimumab
Anti-TNF-alpha indications
PAIR
Psoriasis/psoriatic arthritis
Ankylosing spondylitis
Inflammatory bowel disease
Rheumatoid arthritis
TNF-alpha antagonist mechanism and example
Inhibits TNF alpha and beta
Etanercept - PAR not PAIR
What conditions can IL-1 blockade be used for?
FMF
Gout
Adult Stills
What disorder does IL-6 play an important role in?
Rheumatoid arthritis
How do Tocilizumab and Sarilumab work?
Anti-IL-6 receptor
→ reduced macrophage, neutrophil, T cell, B cell activation
What disorders are IL-23 and IL-17 important for?
Axial spondyloarthropathies
Psoriasis/psoriatic arthritis
IBD (IL-23 only)
Give an example of an anti-IL-23 drug?
Guselkumab
anti-p19(alpha) subunit of IL23
What ILs can be targeted for Asthma and Eczema?
IL4, 5 and 13
How does Denosumab work?
It inhibits RANK-mediated osteoclast differentiation and function → decreased bone resorption
Allergic desensitisation procedure
Start small
Escalate dose every weeek until max dose reached
Maintenance dose given monthly for 3-5 years