Immunology Flashcards
What are 3 examples of live attenuated vaccines?
MMR
BCG
typhoid
Why was the clinical trial for cancer vaccine halted?
Development of meningocephalitis
What can interferon alpha be used for?
Hep a
Hep b
Kaposi’s sarcoma
What receptor does ipilimumab act on?
CTLA4
What is the problem with plasmapheresis?
Rebound antibody production limits efficacy therefore usually given with anti proliferative agent
Give the 3 phases of transplant rejection
1- recognition of antigen
2-activation of antigen specific lymphocytes
3- effector phase
Give 3 risk factors for chronic rejection of a transplant
1- multiple acute rejections
2- HTN
3- hyperlipidaemia
Which types of graft rejection does not respond to immunosuppressants
Chronic
Which types of graft rejection causes fibrosis
Chronic
What does HIV virus bind to during attachment?
Gp120 and gp41 on CD4 T cells
How is HIV diagnosed?
Screening - detects anti-HIV ab via ELISA
Confirmation - detects ab via western blot Requires seroconversion (after 10 weeks)
How long is the incubation period of HIV before seroconversion
10 weeks
What is the most common anti Retrovir HIV drug in pregnancy?
Zidovudine - antelartum PO
Delivery IV Po to newborn for 6/52
What does Zidovudine treatment antenatally decease transmission by?
26%-8%
which immune cells are the basis of innate immunity?
neutrophils
macrophages
NK cells
how common is primary immunodeficiency?
very rare: 1/10,000 live births
give 3 drugs which cause secondary immunodeficiencies
- corticosteroids
- cytotoxic agents
- antiproliferative immunosuppressants
which 3 malignancies cause secondary immunosuppression
- myeloma
- leukaemia
- lymphoma
give 3 infections causeing secondary immunosuppression
- HIV
- Measles
- Mycobacterial infection
what are 6 clinical features that are suggestive of immunodeficiency?
- two major or one major and recurring minor infections in one year
- unusual organisms
- unusual sites
- unresponsive to treatment
- chronic infections
- early structural damage
which antibody is the major antibody produced in mucosal secretions?
IgA
what immunodeficiency is associated with redcurrant respiratory and GIT infections (in 30% )
clue: mucous membranes
IgA deficiency
How many caucasian people are affected by complete IgA deficiency?
1 in 600
What pattern recognition receptors on some immune cells recognise?
PAMPS - pattern associated molecular patterns
e.g. bacterial sugars, DNA, RNA
What are Fc receptors for?
To allow immune cells to detect immune complexes
What is the target for IgG antibodies wen protecting against influenza virus?
Hemagluttinin (HA)
What is the purpose of a depot adjuvant?
Main aim os to increase the immune response without altering its specificity - by promoting antigenic persistance by slowing the release of antigen to be a steady stream
what accumulates in Alzheimers disease?
amyloid and tau proteins (plaques and tangles)
define atopy
the production of specific IgE responses to common environmental antigens
what is the prevalence of allergic rhinitis in adults?
20%
what is the prevalence of atopic dermatitis in adults
5%
What are clinical features associated with IgE mediated allergy?
angioedema, prurirus, urticaria, rhinitis, conjunctivitis, D+V, anaphylaxis
what are 3 investigations you could do to test an allergy?
- skin prick test
- lab measurement of allergen specific IgE
- patch test (48h delayed response)
- challenge test (supervised test)
what is the gold standard investigation for allergy?
skin prick test
what are 3 disadvantages of skin prick tests
- risk of anaphylaxis (1 in 3000)
- limited value in patients with skin conditions such as eczema
- requires expert to interpret
what sort of allergy testing would be indicated for a patient with extensive eczema
specific serum IgE testing
What type of allergy testing would you avoid, and which would you choose in a patient with a history of anaphylaxi?
avoid skin prick test,
chose specific IgE serum testing
what test would you do if a patient suddenly becomes hypotensive and gets a severe rash during anaesthesia?
serum mast cell tryptase - it’s a product of degranulated mast cells and so helps diagnose anaphylaxis
what is the gold standard for diagnosing food allergy
challenge test
A 18 years old lady with a history extensive eczema who is unable to stop taking anti-histamine medication. What is the most appropriate test to look for IgE sensitisation?
IgE serum test (or RAST test)
A 15 year old with a history of asthma and hayfever who notices increasing cough and wheeze shortly after eating peanuts. What is the most appropriate initial diagnostic test ?
component resolve diagnostic (CRD) or IgE serum
what is the management of anaphylaxis
- IM adrenaline 500ug
- Oxygen 100%
- inhaled bronchodilators
- fluid replacement
- hydrocortisone 100mg IV
- chlorpheniramine 10mg IV (skin rash)
what is the most common food allergy in adults (in the USA)
shellfish (2%)
A 35 year old man with a history of spring time hayfever and immediate lip tingling and swelling immediately after eating and apples.
a) What is the most likely explanation for IgE hypersensitivity ?
b) How would you confirm the diagnosis?
c) What tests may be useful to advise on prognosis?
a) birch pollen oral allergy syndrome (OAS)
b) with a skin prick test or RAST
c) CRD (component resolve diagnostics) - can predict severity of reaction
what drugs are a common cause of angioedema, which may be misleading in a doagnosis of anaphylaxis?
ACE inhibitors
What type of disease is Familial mediterranean fever?
Monogenic auto-inflammatory disease
what is the inheritance pattern of familial mediterranean fever?
autosomal recessive
what disease is a result of a mutation in the MEFV gene which codes for pyrin-marenostrin?
familial mediterranean fever
What is the main difference in the mutations associated with monogenic autoimmune diseases, and monogenic autoinflammatory diseases?
Auto-Inflammatory = innate immune response
auto-immune = adaptive immune response
what monogenic auto-immune disease is characterised by a Single gene mutation involving FOXp3 resulting in abnormality of T reg cells
IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X linked)
Name the polygenic auto-inflammatory disease. ~30% patients have a mutation of CARD15 which may affect response of myeloid cells to bacteria.
Chron’s disease
Name a mixed pattern auto-inflammatory / auto-immune disease with >90% heritability that results in inflammation typically involving the sacro-iliac joints and responds to TNF alpha antagonists
Ankylosing spondylitis
which 2 HLA genetic polymorphisms are responsible for a 25 fold increased risk of type 1 diabetes?
HLA-DR3/DR4
What type of hypersensitivity reaction is Goodpasture’s diisease?
Type II - antibody driven. The autoantigen is the Basement membrane collagen type 4 - leading to glomuronephritis and pulmonary haemorrhage
which hypersensitivity reaction type is rheumatoid arthritis?
type III - immune complex driven autoimmune disease, due to the Fc region of IgG causing arthritis
What type of hypersensitivity reaction is SLE?
Type III - immune complex formation
What type of hypersensitivity reaction is eczema
Type 1
which antibodies stimulate the TSH receptor in Graves disease?
IgG
What is the most common cause of hypothyroidism in iodine replete areas?
Hashimoto’s thyroiditis
Why is Hashimoto’s thyroiditis asociated with goitre?
because T and B cells infiltrate it and enlarge it
What antibodies is Hashimoto’s thyroiditis associated with?
anti thyroid peroxidase antibodies
describe the involvement of T cells in T1 diabetes?
CD8 cytotoxic T cells recognise auto-antigens presented by MHC class I molecules on the insulin producing beta cells
What type of hypersensitivity reaction is Grave’s?
Type II
what is the pathology of pernicious anaemia?
antibodies against gastric parietal cells or intrinsic factor, preventing B12 binding and absorption, leading to B12 deficiency, macrocytic anaemia, subacute degeneration of cord leading to peripheral and optic neuropathy
What antibodies are involved in myaesthenia gravis?
antibodies against Acetylcholine receptors
What is the likely diagnosis in a patient with muscle weakness which gets worse on repetetive movements, drooping eye and worse at the end of the day?
Myaesthenia gravis
what 2 investigations can confirm the diagnosis of Myaesthenia gravis?
- ant-Ach receptor antibodies
- EMG (elecromyogram)
- Tensilon test + (inject edrophonium (anti-cholinesterase_ which prolongs the life of Ach and allows it to access residual receptors
Give the autoantibody seen in:
a) Goodpasture disease
b) Myaesthenia gravis
c) Graves disease
D) Pernicious anaemia
E) Diabetes Mellitus
f) Hashimoto’s thyroiditis
a) anti-basement membrane antibody
b) anti acetylcholine receptor antibody
c) Anti TSH receptor antibody
d) anti-intrinsic factor antibody
e) Anti GAD/ anti-insulin / anti-islet cells / anti-IA-2
f) Anti-thyroglobulin, anti thyroid peroxidase antibodies
polymorphisms affecting which inflammatory cytokines increases the risk of RA?
TNF, IL1, IL6, IL10
what environmentla factors are associated with RA?
- smoking (due to increased citrullination)
2. GUM infection with Porphyromonas gingivalis
Why are polymorphisms in PAD (Peptidylarginine deiminases) type 2 and 4 associated with rheumatoid arthritis?
because polymorphisms are associated with increased citrullination, which in turn creates a high load of citrullinated proteins - Th cells then promote development of an antibody response
what antibodies are associated with rheumatoid arthritis
anti-CCP antibodies
rheumatoid factor
What is a rheumatoid factor?
An antibody directed against the common (Fc) region of human IgG
What is the region of the HLA DR beta chain that predisposes to development of rheumatoid arthritis
the shared epitope
What antibody Binds to Fc region of IgG
Rheumatoid fator
What antibody Binds to citrullinated proteins and has ~95% specificity for development of rheumatoid arthritis
Anti-CCP or ACPA
What bacteria is known to expresse PADI enzymes capable of deiminating arginine to form citrullinated proteins
P. gingivalis (gum infection associated with increased risk of RA)
What does staining Hep-2 cells used to detect in patient serum?
anti-nuclear antibodies (ANA)
What is the immunopathology of SLE?
- antibodies bind to antigens, forming immune complexes, 2. imune complees deposi in the tissue
- immune complxes activate complement (classical pathway) resulting in increased inflammatory response
- immune complexes stimulate cells expressing Fc and complement receptors
What are the main targets of ANA in SLE?
dsDNA
extractable nuclear antigens (ENAs) e.g. ribonucleoproteins such as Ro and La, enzymes
Which 2 tests are used to diagnose antiphospholipid syndrome?
- anti-cardiolipin antibody
2. lupus anti-coagulant
what are the features of CREST syndrome?
Calcinosis Rayneuds Eosophageal dysmotility Sclerodactyly Telangectsia
How are diffuse and limited systemic sclerosis different in terms of anatomy?
limited = not beyond forearms (can sometimes include oral mucosa) diffuse = beyond forearms
what antibodies are involved in a) limited and b) diffuse cutaneous systemic sclerosis?
a) limited = anti-centromere antibodies
b) diffuse = anti-topoisomerase antibodies (Scl-70)
What are donors of immunoglobulin screened for before donation?
Hep B, Hep C, HIV
what are pembrolizumab and nivolumab antibodies specific for?
PD-1
what do corticosteroids inhibit, reducing inflammation?
Phospholipase A2, which blocks formation of arachidonic acid and therefore stops prostaglandin formation
Give some side effects of corticosteroids?
cushings, hirsutism, central obestiy, diabetes, pancreatitis, transient neutrophilia, glaucoma, osteoporosis, acne, HTN, peptic ulceration, AVN
Name the 4 cytotoxic antiproliferative agents?
CAMM Cyclophosphamide Azathioprine Mycophenolate Mofetil Methotrexate
which cytotoxic anti-proliferative drug is metabolised into 6-mercaptopurine by the liver?
Azathioprine
which cytotoxic drug cannot be metabolised by people with a TPMT mutation?
Azathioprine
What are general toxic/Side effects of cytotoxic anti-proliferative drugs?
infection, teratogenic, BM suppression, malignancy, hepatotoxicity
what is the mechanism of action of cyclophosphamide (cytotoxic agent)
alkylation of guanine base of DNA, damaging it and preventing cell replication
which cytotoxic drug is indicated for Chrons or UC?
azathioprine
which inhibitor of cell signalling is known for the unwanted side effect of gingival gum hypertrophy?
Cyclosporin
which 2 immunosuppressive drugs work by inhibiting calcineurin?
cyclosporin + tacrolimus
What are the 5 immunosuppressive drugs which work by inhibiting cell signalling?
TACTS - tactics for stopping cell signalling Tacrolimus Apremilast Cyclosporin Tofactinib Sirolimus
What does tofactinib inhibit, and what condition is it used to treat??
JAK
Rheumatoid Arthritis
(Jack SB has RA and is eating tofu with a pen nib)
What does Apremilast inhibit and what can it be used to treat?
PDE4 inhibitor
Works for psoriasis and psoriatic arthritis
Apres ski me last time because I did a bit too much PDeffection4 and I had scaley psoriasis
which cytotoxic drug is associated with infection, in particular PML (progressive multifocal leukoencephalopathy?)
mycophenolate mofetil