2016 Flashcards
what is a BAT and how is it done?
- BAT is a basophil activation test, which measures release of histamine from basophils when mixed with an allergen.
- the most commonly used marker is CD63 to measure basophil activation
- it is done by incubating an allergen and the patients serum and an activation buffer like IL-3, when the allergen binds and cross links IgE this leads to expression of CD63 and CD203
what are the most common way that basophils are activated in CSU?
Binding of Autoantibodies to the high affinity FCeRI receptor (IgE receptor)
name 4 features of photo toxic reactions
- requires a large amount of agent for eruption
- clinical appearance: sunburn, erythema, edema, bullae
- timing: erythroderma (mins to hrs) after sun exposure
- path: direct tissue injury
- incidence: high
name 4 features of photo allergic reactions
- path: immunogenic delayed type 4 hypersensitivity
- timing: onset of eruption is 24-48hrs after exposure
- incidence: low
- small amount of agent is required for rxn to occur
- clinical appearance: eczematous, vesicles, scaling, pruritic
what are lamellar bodies?
- secretory organelles in the upper stratum of the skin layer
- contain phospholipids, enzymes, cholesterol, B defensin 2, proteins and lipases
mutation in AD and the function of that gene
- filaggrin mut
- mutation leads to decreased integrity of skin barrier, loss of hydration and infection inflammation
lab tests to order in EGPA
- CBC w smear for eosinophilia
- ANCA
- IgE
- CRP/ESR
- ?tissue biopsy
histological features of EGPA
- eos infiltrate in vessel
- perivascular necrotizing granulomas
- giant cell vasculitis
most common extra pulmonary manifestations of EGPA
- mononeuritis multiplex or polyneuropathy
2. allergic rhinitis
two phenotypes of nasal polyps
- eosinophilc
2. neutrophilic
in which type of CRS is TGF-b increased
CRSsNP
what is samters triad
- Nasal polyps
- Asthma
- Aspirin sensitivity
define CRS
- persistent symptoms fro > 12 weeks, 2 of which are
- pain or pressure
- obstruction
- discharge
- smell decreased - evidence of inflammation on CT or rhinoscopy
what % of people with AR have conjunctivitis too
60%
treatment of mild to moderate rhino conjunctivitis
non pharma:
- avoidance of triggers and allergens
- HEPA filtres, vacuums, remove carpeting, remove animals, wash bedding
pharma
- PO AH
- INCS
- topical AH eye drops with mast cell stabilizers PRN
3 y.o F with recurrent chest infections, normal CBC and IgGs. What two non invasive tests would you use?
what are three ddx relevant to this age?
- CXR
- sweat chloride
- vaccine titres
ddx
- CF
- PCD
- Asthma
what cytokine mediates IgA class switching in the gut?
CD40L and TGF-B
name of cells that uptake antigen into payer patches
M cells
4 situations in which Xolair is used
- severe allergic asthma
- CSU not responding to 2nd gen AH
- CRS w Nasal polyposis
- Idiopathic anaphylaxis
weight restrictions for Xolaire
3 indications for xolair in asthma
6-12: 20-150kg and IgE 30-1300
12 +: 30-150 kg and IgE 30-700
- uncontrolled asthma on ICS
- sensitization to an aeroallergen on SPT or sIgE
- exacerbation in the last year
4 RFs for OAS
- Pollen allergic
- high sIgE to pollens
- Allergic rhinitis
- Fhx of atopy
- living in are area with high prevalence of pollen
venom testing
- SPT dose
- ID dose
- min and max VIT dose
- 100 mcg/ml
- 1 mg/ml (can start with 0.001 mcg/ml, then 0.01 mcg/ml, then 0.01 mcg/ml)
- min 50 mcg/ml min and 100 mcg/ml max maintenance dose, however can go up to 200 mcg/mL if having breakthrough anaphylaxis to a sting
where does positive and neg selection occur in the thymus?
positive - cortex
negative - medulla
purpose of positive selection
- to rescue thymocytes from apoptosis
- promotes survival of T cells and determining the spectrum of antigens that T cells can recognize
purpose of negative selection
- this process prevents the survival of T cells that if were released into the periphery would cause auto immunity
ddx for conjunctivitis
- VKC
- AKC
- Atopic KC
- Viral infection - adenovirus
- GPC
indications to add LABA
- Step 3 GINA
2. Teen an use ICS/LABA PRN as step 1 or at step 2 can used maintenance and reliever ICS/LABA
Patient has LLR to insect sting, whats your approach?
LLR is no longer and indication for VIT unless the following circumstances
- frequent unavoidable exposure
- unstable CV/resp disease
- elevated serum tryptase
- detrimental effect on QOL
prognosis of milk allergy
- 40% out grow by age 8, and 80% by age 16
what % of children can tolerated BM and EG
70%
what is the heat labile component of milk
what is the heat stable component of milk
- Bos d 4-6 (labile)
- Casein bos d 8 (stable)
CMPA criteria to treat a family member
- emergency condition and no one else available
- minor condition and no one else available
- must not provide ongoing care
1 requirement of physicians related to duty to themselves
- participating in self regulation: includes seeking help from colleagues when needed, protect and enhance own health, lifelong learning
2 criteria for determining costs for the non insured treatment
- nature of the service provided
- patients ability to pay
what are the options for TREGs that are negatively selected
- apoptosis
- cell anergy
- becoming a treg
What is AIRE?
- AIRE is the autoimmune regulatory gene
- it induces expression of self antigens which help in negative selection of T cells in central tolerance
- lack of AIRE leads to auto reactive T cells in the periphery and multi organ AI (APECED)
which cytokines are secreted by Tregs
IL-10
INF-b
what is the phenotype of ADA SCID
T-B-NK-
what is the phenotype in XL SCID
T- B+NK-
defect in IL-2
What is the function of B cells in XLSCID?
- they are present but not functional due to lack of stim from T cells and absent signalling from IL4 and IL21
what is ADA and why does it cause SCID?
- ADA is an enzyme found in cells that catalyzes the deamination of adenosine and deoxyadenosine
- in ADA def you get a build up of metabolites which is toxic to lymphocytes
why do patients with PJP and SCID get worse after transplant?
- Immune reconstitution syndrome: a systemic inflammatory response that occurs after treatment is started, it is a paradoxical reaction
name 2 polysaccharide vaccines
- pneumococcal
- hib
they require B cells to function and are used to assess the response to polysaccharide antigens
name 2 protein vaccines
- tetanus
- diptheria
require both T and B cell functioning
evaluation ab mediated response to protein antigens
what binds C1q hexamer?
- IgM and IgG
define desensitization
increase in reaction threshold to an allergen while receiving active therapy, often a temporary state which depends on continuous exposure
define tolerance and give two features of it
- state of not reacting to an allergen
- the end goal of desensitization
features
- movement away from Th2 response
- permanent protection
- non responsiveness of immune system to antigens
what are adjuvants?
- a compound or molecule incorporated with allergen/antigen to enhance immunogenicity
why are adjuvants needed for pollen IT?
- to increase immunogenicity without increasing allergenicity
list 3 adjuvants in AIT
- CpG
- Aluminum hydroxide
- calcium phosphate
what is the difference between protein and polysaccharide vaccine
Protein - B cell response T cell dependent, get formation of memory cells and isotype switching
Polysaccharide - B cell response is T cell independent, no isotype switching, limited memory
Name lab tests in anaphylaxis and when to measure them
Serum total Tryptase - ideally 30-120 min from reaction, but up to 6 hours is still acceptable
Mature trypase - ideally 30-90 min from rxn
24 hr urine histamine - may be elevated in urine collected up to 24 hrs after symptom-onset
24 hr urine n - methylhistamine
24 hr urine prostaglandin
Can pts with a sulfa allergy have latex
Yes.
Those with sulfonamide abx allergy are not at increased risk of reaction with non-abx sulfonamide. Exceptions include sulfasalazine, which is broken down into sulfapyridine which is similar to the structure in sulfonamide abx. Also possible dapsone.
Differences between innate and adaptive immune system
Innate:
- involves NK cells, neutrophils, monocytes and macrophages
- uses receptors that recognize PAMPS (LPS, flagellin, nucleic acid)
- non specific recognition
- occurs minutes to hours
- no memory is created
Adaptive - specific refined recognition
- uses B and T cell receptors that recognize specific antigens on pathogens
- uses CD4 and CD8 t cell
- immunity is generated by recombination of VDJ regions and hyper variation
what defines protection after pneumovax
There are 23 antigens in the pneumovax vaccine
>/= 1.3 ug/mL Ab titer, a normal person will have a 2 x increase in 70% of the serotypes assayed defines protection in >6, in under 6, this number is 50%.
which vaccines cause a secretory IgA response
- rotavirus
- intranasal influenza
- oral polio
- oral typhoid
RFs for RCM rxn
Female
Asthma
Previous rxn to RCM
Bblockers or cardiac comorbidity
Mgmt of RCM hypersensitivity
Use different RCM than previous time - use non-ionic, hypo/iso-osmolar
Avoid RCM if possible
Medic-Alert bracelet
Can consider pre-medication prior to next procedure, although not strong evidence that it is effective:
Prednisone 50 mg 13, 7, and 1 hr prior
OAH 1 hour prior
most common cause of CVID
- idiopathic or unknown
- genetic mutations in NKKB1 and TACI
non infectious complications of CVID
- ILD
- Malignancy
- Autoimmunity
- GI manifestations
- Splenomegaly