Immunology Flashcards
A 35 year old woman presents with persistent itchy wheels for the last 2 months. She noticed that when this is at its worst, she also has a fever and feels generally unwell. After an acute attack, she has bruising and post-inflammatory residual pigmentation at the site of the itching.
Chronic Urticaria
Type II (IgG) note acute uritcaria is Type I
Persitent Itchy wheels
Angiodema can occue
Increased ESR
TX: Responds well to histamine. If it does not respond it is not Chronic Urticaria.
Q) WHy not acute? Acute urticaria lasts less than 6 weeks.
This 45 year old woman presents to A&E with tongue swelling and acute respiratory tract obstruction.
She has longstanding hypertension and received a renal transplant two years previously. She has no history of a_llergic disease_. On examination her blood pressure is stable, and examination of her lung fields reveal normal breath sounds. Her current medication includes cyclosporine, azathioprine, captopril and nifedipine.
What is the condition?
Acute angioedema
This 45 year old woman presents to A&E with tongue swelling and acute respiratory tract obstruction. She has longstanding hypertension and received a renal transplant two years previously. She has no history of allergic disease. On examination her blood pressure is stable, and examination of her lung fields reveal normal breath sounds. Her current medication includes cyclosporine, azathioprine, captopril and nifedipine.
What is the condition?
Acute angioedema. This woman has angioedema of the tongue, without symptoms suggestive of a generalised allergic reaction. Isolated angioedema may be allergic in origin, but 94% of cases angioedema presenting to A&E are drug induced and the majority of these are associated with ACE inhibitors (eg captopril).
A 19 year old male presents to A&E with increasing breathlessness. On examination his BP is 90/55 mmHg and his respiratory rate is 28/min. He shows you a generalised red itchy skin rash, and examination of his chest reveals bilateral inspiratory and expiratory wheezes throughout.
IM adrenaline 1 mL of 1:1000
A 35 year old woman presents with a two day history of a red itchy skin rash which started soon after her first scuba-diving lesson. She is otherwise well.
What is it? How would you treat it?
PO antihistamines -acute urticaria type I
A 22 year old woman is presents with this intermittently itchy and desquamating skin rash which is unresponsive to antihistamines
None of the above
A 40 year old man complains of loss of smell with nasal itching and discharge over 4 weeks. He also describes morning sneezing. He is otherwise in good health. On examination his nasal mucosa are swollen and hyperaemic.
PO antihistamines
Allergic
Rhinitis
This 45 year old woman presents to A&E with tongue swelling and acute respiratory tract obstruction. She has longstanding hypertension and received a renal transplant two years previously. She has no history of allergic disease. On examination her blood pressure is stable, and examination of her lung fields reveal normal breath sounds. Her current medication includes cyclosporine, azathioprine, captopril and nifedipine.
IM adrenaline 0.5 mL of 1:1000
Elevate Legs
100% Oyxgen
- IM Adrenaline 500 mcg
- Inhaled bronchodilators
- Hydrocortisone 100mg IV,
- Chlorphenamine 10mg IV,
- IV Fluids, Seek Help
Cytokines exerting an anti-viral effect
infereron
Immunoglobulin dimer
What other types of IgG do you knw?
IgA:
IgA: mucosal areas, saliva, tears, breast milk
IgE: allergy – histamine release from mast cells
IgG: can cross from placenta to foetus
IgM: on surface of B cells
Immature B cells express only IgM.
Human normal Ig has a half life of 18 days
MHC associated with Th1 cells
Major histocompatibility complex class 2
Reminder – Immune Recognition
T-Cells (TCs) recognise antigen with
MHCs on APCs
B-Cells (BCs) can recognise just
antigen
Acts on hepatocytes to induce synthesis of acute phase proteins in response to bacterial infection (complement activation)
IL6
Arise in the first few days after infection and are important in defence against viruses and tumors
Natural Killer cells
MHC associated with Th2 cells
Major histocompatability complex class I
MHC associated with cytotoxic T cells
Major histocompatability complex class 1
Along with IgD, is one of the first immunoglobulins expressed on B cells before they undergo antibody class switching
IgM
The most abundant (in terms of g/L) immunoglobulin in normal plasma
IgG
Deficiencies in this predispose to SLE
Classical complement pathway: C2 and C4 measured by CH 50
Kostmanns syndrome is a congenital deficiency of which component of the immune system?
Kostmann Syndrome-no pus
- Severe congenital neutropenia
- Mainly Autosomal Recessive (HAX-1)
- 1-2 cases per million
Patients have infections shortly after birth
Diagnosis based on chronicallLlow Neutrophil count and bone marrow test showing an arrest of neutrophil precursor maturation
- Treatment includes G-CSF, prophylactic antibiotics and BMT if G-CSF is ineffective
Which infection is most common as a consequence of B cell deficiency?
Bacterial
Meningococcal infections are quite common as a result of which deficiency of the component of the immune system?
Complement
Produced by the liver, when triggered, enzymatically activate other proteins in a biological cascade and are important in innate and antibody mediated immune response?
Which interleukin acts on the liver to activate complement?
Complement
Answer: IL-6
A complete deficiency in this molecule is associated with recurrent respiratory and gastrointestinal infections.
Selective IgA Deficiency
Most common defiency
Reccurent gastro and resp infections
Affects 1 in 600 Caucasians
70% are asymptomatic
Leukocyte Adhesion Deficiency is characterised by a very high count in which of the white cells? What other findings would be?
Whcih molecule is dysfunctional in this syndrome?
What would be the presentation?
Neutrophils
B2-integrin
A) Deleyed umbilical cord separation, and high neutrophil count.
Which crucial enzyme is vital for the oxidative killing of intracellular micro-organisms?
NADPH oxidoase
Which complement factor is an important chemotaxic agent?
C3a
What is the functional complement test used to investigate the classical pathway?
CH50
Graves Disease
antibodies
treatment
type of hypersentivity reaction
Type II – Antibody mediated
anti-TSH
carbimazole
SLE
Type Hypersnsitivity
antibodies present (6)
D.
- Type III – Immune complex mediated
- ANA
- antiSM
- anti dsDNA
- Beta-2-glycoprotein
- Anti-cardiolipin
- Lupus anti-coagucalant.
Rheumathoid artheritis
type of reaction
- Type III and Type IV
- type IV - delayed hypsensitivity T-cell mediated
- Type III - IgM antibodies vs Fc region of IgG.
RF (+)
- Anti-CCP (95% specific)
- Increased ESR
Asthma
type of reaction
pathology involved
- non-immune mediated
- SM cell hyperplasia
- excess mucus
- inflammation=Group of immune-mediated lung disorders caused by intense/prolonged exposure to inhaled ORGANIC antigens → widespread ALVEOLAR inflammation (cf asthma = airway inflammation).
Type 1 diabetes
Type IV – T-cell mediated
Pancreatic Beta Cell proteins. (Glutamate Decarboxylase GAD)
Insulitis
Beta Cell Destruction
Immune thrombocytopaenic purpura
How does it present?
What sort of reaction it is?
Where antibodies bind to?
- Type II - abnomral IgG** and IgA
- Generally asymptomatic illnes following viral infection or immunisation in children less than <10 years and adults>65
- Petchial Rash
- Low platelets is the only finding. In adults you need to do bone marrow biopsy to exclude myoplastic syndrome.
- Glycoprotein IIb/IIIa on platelets
- Bruising/ Bleeding (Purpura)
- Anti-Platelet Antibody
- Steroids, IVIG, Anti-D Antibody, splenectomy
/ABO hemolytic transfusion reaction. What type of reaction is it?
Type II – Antibody mediated
Hepatitis C associated membranoproliferative glomerulonephritis type I
Q) Type of immune reaction it is
Q)
- Type III – Immune complex mediated
- Mixed Essential Cryoglobuinaemia
- gM against IgG +/- hepatitis C antigens
Joint pain, splenomegaly, skin, nerve and kidney involvement. Associated with Hep C.
A mixture of clinical and biopsies
NSAIDs, Corticosteroids and plasmaphoresis
GOOdpasture’s syndrome?
1) What type of reaction is it?
2) How does it present?
3)
Type II – Antibody mediated
a) of pulmonary renal syndrome: pulmonary haemorrhage with rapidly progressive glomerulonephritis. so hemoptysis and blood in the pee.
b) Remeber always two things in GOODPASTURE
c) Linear smooth IF staining og IgG deposit in BM.
A 32yr old woman complains of fatiguability in many muscles and double vision. She is thought to be at risk of other autoimmune diseases as she has a family history of various autoimmune diseases and herself has autoimmune hypothyroidism. Her thyroid function is normal because she is well replaced with thyroxine. What might be causing her muscle weakness?
What type of reaction it is?
Myaesthenia gravis
Type II – Antibody mediated
Recurent bacteria infections 3 months after birth.
What is the model of inheritance?
What is lacking?
Which gene is mutated?
Bruton’s Agammaglobulinemia
- X-Linked Tyrosine Kinase Defect
- Mutation in BTK gene
- Failed production of mature B-Cells and antibodies. T cells would be present
- No antibodies
- Symptoms after 3-6 months
DiGeorge’s Syndrome
1) how does ir present?
2) what sort of infections is he predisposed to?
DiGeorge’s Syndrome (CATCH 22)
Impaired development of the 3rd and 4th pharyngeal pouches (oesophagus, thymus, heart)
22q11.2 deletion – 75% sporadic
Low set ears, cleft lip and palate
Low calcium > seizures
Susceptibility to viral infection
V. low numbers of mature T cells
(absent thymus)
Treated by thymus transplant
Treatment of T cell deficiencies: infection prophylaxis, Ig replacement if necessary, specific other treatments.
Infants present with recurrent infections, failure to thrive, and chronic diarrhoea.
1) what is it?
2) what is lacking?
3) what is model of inheritance?
4)
IL-2
- Severe Combined Immune Deficiency (SCID)
- lymphoid tissue precursors IL-2 receptor
- pattern of inheritence
- Failure to thrive and persistent diarrhoea & early infant death
- Low or normal B cell numbers, reduced T cells, low antibodies
BMT only established treatment
45% are X-linked
Small platelet size is the one consistent feature. Eczema and reccurent infections are common.
Q) What is it?
Q) What is the model of inheritence?
Q) What does it increases the risk of?
Wiskott-Aldrich Syndrome
X-linked condition characterised by thrombocytopenia.
Small platelet size is the one consistent feature.
Eczema and recurrent infections are common.
There is an increased risk of haematological malignancies.
1) Failure to thrive by the age of three months
2) The child presents with jaundice and hepatosplenomegaly
2) Which Immunoglubins will be low?
3) Which Immunoglobulin will be normal?
Bare Lymphocyte Syndrome:
Bare lymphocyte syndrome
Absent expression of HLA molecules within thymus
lymphocytes fail to develop
Type 1: MHC I absent - ↓CD8 cells
Type 2: MHC II absent - ↓CD4 cells
BLS type 2 more common:
B-cell class switch needs CD4 therefore less I_gA_ and IgG made.
IgM would be normal
- Associated with Sclerosing Cholangitis
Unwell by 3 months of age
Boys present first years of life with
recurrent bacterial infections esp.
Pneumocystis carinii & failure to thrive
What is the mechanism?
Hyper IgM
Activated T-cells cannot interact with B-cells to class switch
Therefore B-Cells cannot make IgA and IgG, but elevated IgM
A 25 year old woman comes to her GP about family planning. She is worried because she had an older brother who died before she was born and her grandmother lost two children which she things were both boys. Her GO thinks there may be a genetic disorder in her family affecting the IL-2 receptor. If correct she has a 50% of inheriting the trait from her mother and being a carrier herself. And there would be a 50% chance of passing it to her children. If inherited, her daughters would be carriers and her sons would require treatment which is usually a bone marrow transplant but gene therapy is sometimes used.
Severe Combined Immune Deficiency (SCID)
- Defects in lymphoid precursors e.g. Adenosine Deaminase Gene; IL-2 receptor
- Recurrent infections
- Failure to thrive and persistent diarrhoea & early infant death
- Low or normal B cell numbers, reduced T cells, low antibodies
- BMT only established treatment
- 45% are X-linked
A jaundiced 8 month old child presents with failure to thrive, and a history of recurrent infections (viral, bacterial and fungal). On examination there is hepatomegally and blood tests show a raised alk phos and low CD4 count. A defect is found in the proteins that regulate MHC Class II transcription.
BARE LYMPHOCYTE SYNDROME
Patient X’s GP writes inquiring about whether to vaccinate. The patient suffers from recurrent respiratory tract infections and has been diagnosed with one of the B-cell maturation defects. For which one is immunisation still effective?
Selective IgA Deficiency
Most common defiency
Reccurent gastro and resp infections
Affects 1 in 600 Caucasians
70% are asymptomatic
For which disorder would a bone marrow transplant be unhelpful but a thymic transplant may provide a cure?
DIGEORGE CATCH-22
A difference in this between host and recipient is the main cause of transplant rejection
HLA
Along with anti-HLA antibodies, the most important screen to ensure a match before transplantation
ABO blood type
Risk factor for chronic allograft rejection
Hypertension
Hyperlipidaemia
Transplanting an ABO incompatible kidney will result in ___ rejection
1) Why
2) what would be the consequence?
3) How it could be prevented?
Hyperacute
Preformed Ab which activates complement
Thrombosis and Necrosis
Prevention: Crossmatch (ABO groups) HLA-matching
You are about to see a gentelman following kidney transplant developng vascullitis following 2 weeks of his transplant.
1) What is it?
2) Wha is the mechanism?
2) What is the treatment?
Acute organ transplant
B cell producion and antibody attacking the blood vessls leading to vasculitis
The treatment would be to remove the antibody = plasmapharesis and immunospuression
Treatment of acute cell mediated rejection
what is the pathology involved?
How does it work?
High dose corticosteroids
CD4 activating a Type IV
reaction
Cellular
Infiltrate
T-Cell
Immunosuppression
The 3 most important HLA types to screen for in renal transplantation when matching donor and recipient, in order of importance
HLA DR > B > A
The 3 most important HLA types to screen for in renal transplantation when matching donor and recipient, in order of importance
B.
HLA DR > B > A
Lymphocyte that responds to foreign HLA DR types
P.
CD4+ T cells
Lymphocyte that responds to foreign HLA A types
CD8+ T cells
Prevents DNA replication especially of T cells?
How it can prevent replication?
What is it used for?
Mycophenolate Myofeti
Prevents Guanine Synthesis
Transplantation
Autoiimune
Vascullitis
Causes a transient increase in neutrophil count
Prednisolone
Monoclonal antibodies inhibiting the actions of cytokines
Infliximab
Can cause gingival hypertrophy as a side effect
how does it work?
Ciclosporin
inhibits Calceurin
whihc normally activates the transcription of Il-2, thus reduces T cell proliferation
Administration of this may boost the immune system
Immunoglobulins
prevent lymphocyte proliferation by inhibiting DNA replication, affects B cells more than T cells.
Q) What is it used for?
Cycloophoshamide. Both mycophenolate mofetil and cyclophosphamide prevent lymphocyte proliferation by inhibiting DNA replication. However, mycophenolate mofetil is more selective for T cells, whereas cycophosphamide affects B cells more than T cells.
Note that cyclophosphamide at high doses will affect all cells with a high turnover.
b) connective tissue disease, vascullitis
Bone marrow suppresion, infection, malignancy
_Corticosteroids,_ as well as being directly lymphotoxic in high doses, icell via which other mechanism?
What else does it do?
- Blocking cytokine synthesis
- Inhibits PLA12, hence blocks archaidonic acids
- Reduces prostaglandin synthesis
- Inhibits phagocyte trafficing
- Phagocytocis and relase of proteolytic enzymes
The antiproliferative drug cyclophosphamide inhibits lymphocyte proliferation by which mechanism?
Inhibition of DNA synthesis
Plasmapheresis may be indicated in which conditions?
Goodpasture’s syndrome- removal of anti-GBM antibody
Myasthenia Gravis - nACHR antibodies
Vascular Transplant rejection - hyperacute but aapears 6 days afterwards
Example of a vaccine that should NOT be given to a severely immunocompromised patient.
POLIO
MMR BOY
A condition where antigen desensitization therapy may be indicated.
Bee/wasp venom allergy
The main side effect of this drug is diabetogenic drug
How does it work?
is also used in the treatment of other T cell-mediated diseases such as eczema (for which it is applied to the skin in a medicated ointment), severe refractory uveitis after bone marrow transplants, exacerbations of minimal change disease, and the skin condition vitiligo.
Tacrolimus
Inhibits calceurin, which normally inhibits synthsis of IL-2 thus T lymphocyte proliferation.
How does it work?
Main SE Predinolone
Transistent neutrophilia
Hypertension
Glaucoma
Antimetabolite agent
Metabolised by liver to 6 mercaptopurine,
blocks de novo purine (eg adenine, guanine)
synthesis – prevents replication of DNA,
preferentially inhibits T cell activation &
proliferation
What is its main side effetc?
Azathropine
Bone marrow supression
inhibits dihydrofolate reductase (DHFR), therefore decreases DNA synthesis
Methotrexate
Bone Marrow Supression
Pnemottis, Pulmonary Fibrosis, Cirhiosis
What is conjugate vaccine vaccine?
Pneumococcal vaccine
A conjugate vaccine is created by covalently attaching a poor antigen to a strong antigen thereby eliciting a stronger immunological response to the poor antigen. Most commonly, the poor antigen is a polysaccharide that is attached to strong protein antigen.
A live attenuated viral vaccine
Live attenuated: BCG, MMR,
typhoid
Inactivated preparations of the bacteria
Whole cell typhoid vaccine
- Yellow fever
- BCG
- Typhoid
Extracts of or detoxified exotoxin product by a micro-organism.
tetanus vaccine
Diphtheria, Tetanus