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Allergy and Immunology > deck 1 > Flashcards

deck 1 Flashcards

1
Q

What is a type I reaction?

A

occur promptly after sensitized individual is exposed to an antigen, mediated by specific IgE antibody. cross-plinking of IgE on the surface of mast cells an basophils lead to histamine release/other inflammatory mediators release
examples: immediate hypersensitivity - allergic rhinitis and urticaria
anaphylactoid reactions - similar, but caused by degranulation of mast cells ann basophils WITHOUT specific IgE

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2
Q

What is Type II reactions?

A

Antibody against antigen components of blood or tissue cells or foreign antigens, results in cell destruction.
can be IgM, IgG or IgA antibodies, they bind to the cell surface and activate the entire complement pathway , triggers mast cell degranulation, leads to inflammatory mediator release
examples: autoimmune hemolytic anemia and Rh/ABO hemolytic disease of the newborn; other examples (from baby Nelson): thrombocytopenia, basement membrane molecules in the kidney (GOodpasture), myasthenia gravis, Graves disease
IgG or IgM involved, complement is the mediator

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3
Q

What are type III reactions?

A

antigen-Ab complexes form, deposited in the lining of blood vessels, and filtering organs (i.e. liver, spleen, kidney)
activate the complement cascade, recruit neutrophils, leads to inflammation
ie: serum sickness and immune complex-mediated renal diseases (i.e. PSGN), also hypersensitivity pneumonitis
complement and anaphylatoxin are mediators
Timing (baby nelson ) 1-3 hours after drug exposure (i.e. for serum sickness), arthrus reaction can happen earlier after

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4
Q

Type IV reactions?

A

involve T cell-mediated tissue inflammation and typically occur 24-48 hours after exposure (baby Nelson says 2-7 days after drug exposure)
ie: tuberculin reactions, contact dermatitis , graft vs host disease
lymphocytes involved, cytoins are mediators (include IFN alpha, TNF, alpha, GMCSF)

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5
Q

What is the best biological marker for anaphylaxis?

A

tryptase, although it is still rather insensitive
early mediators of anaphylaxis: histamine, tryptase, chymas, heparin, proteases
late mediates: prostaglandings, leukotriene and cytokines

steps of type I hypersensitivity:
develop depends on :
hereditary predisposition, sensitization by exposure, subsequent reexposure to the antigen
IgE towards specific allergens bound o receptors on mast cells an dbasophils, cell gets activated by cross linking IgE antibodies and leads to the release of mediators

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6
Q

Examples of type I hypersensitivity

A

alergic rhinitis (most common)
urticaria
anaphylaxis (most severe)

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7
Q

How is type I hypersensitivity diagnosed?

A

skin testing
percutaneous skin test - in vivo method to detect IgE antibody to specific allergens ; how it works, the IgE cross links and causes mast cell degranulation leads to histamine release
skin prick test - safest and most specific test: correlates best with symptoms
- interpret by measuring maximal diameter of wheal and flare 15-20 minutes after infecting with the allergen (via prick/puncture or intradermal infection)
- intradermal thought to be more sensitive than prick tests, but specificity is poor , should only use when ruling out allergic disease is essential (i.e. skin prick test is better)
- compare with negative control (saline) and positive control (histamine)

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8
Q

What are 4 contraindications to allergic skin testing:

A

1) recent use of anti-histamines (histamine control will be negative)
2) skin disease limits the area available for testing (i.e. dermatographism or extensive dermatitis)
3) during an asthma exacerbation or episode of anaphylaxis
4) when a patient is taking a beta blocker, because this could interfere with epi to treat test-induced anaphylaxis

in these cases, in vitro testing is a good alternate
can do with a few millilitres of blood

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9
Q

Which are more sensitivite, in vitro tests or skin prick tests for allergy?

A

in vitro tests are
1) less sensitive than allergy prick tests (especially less sensitive for aeroallergens, drugs and hymenoptera)
2) more expensive than allergy prick tests
see table on pg 113 for comparisons
also, in vitro not affected by any drugs, including steroids, vs skin test will be affected by antihistamines and not usually affected by corticosteroids**
(also baby nelson pg 273 comparison)

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10
Q

What organ is most commonly involved in anaphylaxis?

A

the skin

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11
Q

True or false - skin testing is commonly affected by steroids

A

false - not commonly affected by steroids

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12
Q

True or false - life-threatening reaction to hymenoptera is common in childhood

A

false - not common in childhood, compared to common opinion.

most common are large local reactions or generalized urticaria

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13
Q

A child presents with a large local reaction after a bee sting. The parents want to know how long it will last. What do you tell them?

A
  • continuous with sting, starts 12-24 hours after sting, peaks in 2-3 days, lasts 1 week and should be treated with antihistamines and NSAIDs
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14
Q

The same parents want to know if their kid needs an epi pen.

A

excellent long-term prognosis, do not need allergy testing, do not need to carry epi
**the risk for systemic anaphylaxis from stinging insets in children with symptoms confined only to the skin is equal to the risk in the general population

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15
Q

Two day’s later, the child’s sibling presents with generalized urticaria after a bee sting. They really need to get rid of the bees. Does this kid need epi?

A

Yes, at present, the consensus among allergists suggests that children with a history of generalized urticaria from stinging insects carry epi

these kids don’t need skin testing or desensitization

**ps all from Zitelli

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16
Q

That night on call, the neighbour of the first two kids arrives with an anaphylactic reaction. After he is stabilized and being prepared for discharge, what do you tell the parents about follow up and treatment ?

A

anaphylaxis after sting: should get allergy testing and if positive, should get immunotherapy
testing should be done 4 or more weeks after reaction (if you do it too soon, risk of false negative)
immunotherapy protects from anaphylaxis in 95-100% of patients (for wasps, yellow jackets,hornet etc), less for honeybees (80%)

(unrelated immunotherapy also works for desensitization of pollens, dust mites, and cat and dog proteins)

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17
Q

What bug is the most common cause of hymenoptera anaphylaxis in US

A

yellow jackets

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18
Q

What are the two big categories of food allergy? (zitelli figure 4-9)

A

1) IgE mediated hypersensitivity (anaphylaxis, oral allergy)

2) non IgE mediated

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19
Q

What are some examples of non igE mediated food allergy?

A
  • food protein enteropathy, milk protein enterocolitis, lactose intolerance

from either mechanism: eosinophilic gastroenteritis, atopic dermatitis

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20
Q

True or false - most kids will outgrow type I reactions to milk and egg

A

true - these reactions usually more mild (i.e. urticaria) and in first year of life, usually outgrow them

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21
Q

What percentage of kids will outgrow a type I hypersensitivity peanut allergy?

A

<25%

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22
Q

What is oral allergy syndrome?

A

aka pollen food syndrome
patients have underlying seasonal allergic rhinitis and develop pruritus and angioedema of the oropharynx when ingesting fresh fruits and veggies - cross reactivity between proteins in some fruits and veggies and outdoor seasonal pollens , can eliminate the reaction by heating the veggie/fruit

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23
Q

True or false - milk protein enterocolitis is IgE mediated

A

no, bloody diarrhea in few months, improves with removing milk proteins front eh diet.
non IgE mediated so neither allergy skin prick nor in vitro helps (i do think there is aIgE form too, will need to read more about this)

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24
Q

What is the time of onset of each of the hypersensitivity types?

A

type 1: <30 min (immediate) 2-12 hours (late phase
type II: minutes/hours
III: 4-8 hours
IV: delayed type 24-48 hours

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25
Q

what is the major determinant in penicillin?

A

once penicillin enters the body, it is converted to a reactive intermediate, binds to nearby proteins, forming penicilloyl amides
these are called the major antigenic determinant
small amount is in the body as a minor determinant
Skin testing with the major determinant, penicillin and minor determinant - negative predictive value of 100% , 10-20% of skin tests from minor determinant

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26
Q

How long after drug exposure does serum sickness start?

A

1-3 weeks after drug exposure, involves fever, malaise, arthralgia, arthritis, urticaria, lymphadenopathy
many patients have a characteristic serpiginous, erythematous or purpuric rash
decreased C3 and C4, immune complexes
triggers (baby Nelson): blood products, foreign proteins (i.e. antithymocyte globulin and antivenins)
medications: penicillin, sulfonamides, minocycline, cefaclor, hydantoins, thiazides
can happen more soon in a patients who was previously sensitized
rare complications: carditis, GN, Guillain Barre, encephalomyelitis, peripheral neuritis

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27
Q

What is the treatment for serum sickness

A

baby Nelson: self-limited should resolve in 1-2 weeks, treatment is symptomatic
antihistamines for pruritus, NSAIDS for fever and joint pain , if needed can give prednisone
allergy skin testing doesn’t predict serum sickness

antihistamines steroids if doesn’t work
should resolve within a few weeks

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28
Q

Common trigger for TEN

A

almost always drug induced

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29
Q

Comon trigger for SJS

A

drugs (1-3 weeks before)
infection: mycoplasma, HSV
no universal therapy: some say IVIG

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30
Q

Can we use steroids for SJS?

A

no, relatively contraindicated some studies have shown a deleterious effect

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31
Q

What is DRESS syndrome?

A

drug rash with eosinophilia and systemic symptoms
initially described with anti-convulsant therapy
start 2-6 weeks after therapy
rash, fever, increased eosinophils, multi organ dysfunction
LVR most commonly involved, steroids not well studied

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32
Q

What is the most common cause of chronic urticaria?

A

idiopathic
(in contrast to acute)
chronic has to last at least 6 weeks

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33
Q

Which part of the complement cascade is defective in hereditary angioedema?

A

automsomal dominant disorder
absence/abnormal function of a protein int eh complement cascade known as C1 esterase inhibitor
recurrent bouts of swelling, most often triggered by minor trauma
face, genitals, GI tract, extremities, and resp tract most commonly involved
C2 and C4 also low
Dx: measure the C1 esterase inhibitor

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34
Q

What are the warning signs for an immunodeficiency?

A
  1. 4 or more new ear infections within 1 year
  2. two or more series sinus infections within 1 year
  3. 2 or more months on antibiotics with little effect
  4. 2 or more pneumonias within 1 year
  5. failure of an infant to gain weight or grow normally
  6. recurrent deep skin or organ abscesses
  7. persistent thrush or fungal infections in mouth or elsewhere on skin
  8. need for IV antibiotics to clear infections
  9. two or more deep-seated infections including septicaemia
  10. A family history of primary immunodeficiency

if someone has 1- 2 or more of these signs, should consider.

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35
Q

Which primary immune deficiencies that affect lymphocytes are typically associated with neutropenia?

A
  1. X linked agammaglobulinemia
  2. hyper IgM syndrome
  3. severe T cell defecs/rare NK cell deficiencies
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36
Q

Name 4 diseases associated with early complement deficiencies (C1-C4, factor I and H)

A

autoimmune diseases ie

  1. glomerulonetphritis
  2. SLE
  3. dermatomyositis
  4. scleroderma
  5. vasculitis
  6. infections with encapsulated organisms
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37
Q

Describe disease associated with late complement deficiency (C5-C9)

A

recurrent neisserial diseases

all the complement deficiencies can be inherited
C2 and C4 most common

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38
Q

What triggers are associated with hereditary C1 inhibitor deficiency

A

causes hereditary angioedema
trieggers include:
infections, OCP, pregnancy, minor trauma, stress
autosomal dominant condition
(failure to inactivate complement and kynin)

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39
Q

Symptoms of C1 inhibitor deficiency

A

recurrent facial and extremity swelling
abdominal pain
hoarseness/stridor

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40
Q

Which laboratory tests appropriately evaluate the phagocytic system?

A
  1. Absolute granulocyte count
    Antineutrophil antibodies (although only found in half the cases of autoimmune neutropenia of infancy); bone marrow biopsy
  2. Specific Assays include:
    a) determination of chemotaxis (not routinely used)
    b) quantification of nutrophile adherence - measure the expression of leukocyte function antigen-1 by flow cytometry
    c) Determination of respiratory burst:
    - nitroblue tetrazolium test - not used much anymore
    - ***dihydrorhodamine (DHR) 123 test - in activated granulocytes reactive oxygen intermediates reduce DHR 123 to rhodamine 123 (increased fluorescence on flow cytometry)
    d) enzyme assays
    e) treatment with rHu GCSF - autoimmune neutropenia should respond fairly quickly, congenital forms take longer and larger doses
    f) mutational analysis
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41
Q

What are the main disorders of defective phagocytosis

A

Defective phagocytosis (10% of primary immunodeficiency). Main ones to know

  1. chronic granulomatous disease
  2. hyper IgE (Job)
  3. Chediak Higashi
  4. Leukocyte Adhesion Deficiency
  5. Schwachmann Diamond
  6. Kostmann syndrome
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42
Q

6 week old baby with erythema and induration around his umbilical cord which is still firmly attached. What underlying condition should you suspect?

A

Leukocyte Adhesion Deficiency
Zitelli – rare but most commonly from deficiency in CD18 (needed for neutrophils to exit blood vessels and enter tissue). range of disease from mild to severe.
Symptoms include delayed umbilical cord separation, persisten and dramatic peripheral blood granulocytosis (ie increased neutrophil), recurrent soft tissue infections and impaired wound healing
Will not form pus
Should suspect in any baby with periumbilical problems and persistent peripheral blood leukocytosis
**however, most babies with delayed separation of umbilicus will not have LAD (since it is rare)
normal umbilicus: separates by 10 days on average, normal from 3-45 days (secretes)

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43
Q

What are the pathological findings in LAD?

A
  1. persistent neutrophil leukocytosis
  2. lack of neutrophils at sites of infection (necrotic areas without pus)
  3. severe lymphocyte deplesion in lymphoid tissues
  4. impaired wound healing

labs: flow cytometry - detect CD11/18 antigens on WBCs (should be low in LAD)

44
Q

What are the manifestations of severe disease from LAD in newborn?

A

delayed separation of the umbilical cord (normal average 10 days, between 3-45 days normal)
omphalitis
persistent leukocytosis (>50 000 cells/mm3 often) in newborn period
high neutrophils but they can’t get there they need to go
severe disease: usually die before 2 years of age
Treatment: bone marrow transplantation

45
Q

What are the manifestations of severe disease from LAD in childhood after infancy?

A

severe sinusitis
destructive periodontis
recurrent infections with : S. aureus, gram-negative enteric bacteria, also with fungi

46
Q

What is the molecular defect in chronic granulomatous disease?

A

profound defect in the oxygen metabolic burst in the myeloid cells following phagocytosis of microbes
therefore, they lack superoxide oxygen radicals and peroxide ->cannot kill catalase-positive bacteria and fungi

47
Q

Name 5 organisms that people with CGD are especially vulnerable too

A 
catalase positive bacteria and fungi, 5 main organisms:
1. S. aureus
2. Burkholderia cepacia
3. Serratia marcescens
4. Aspergillus 
5. Nocardia 
6. salmonella 
(gram negative catalase psotivie - e. coli, klebsiella, enterobacter, salmonella) **not sure if all of these are the most common, salmonella is for sure 
candida
48
Q

What lab test should you do to diagnose CGD?

A

flow cytometric DHR 123 test
***dihydrorhodamine (DHR) 123 test - in activated granulocytes reactive oxygen intermediates reduce DHR 123 to rhodamine 123 (increased fluorescence on flow cytometry)
old test: nitroblue tetrazolium reduction test

49
Q

A 3 year old child presents with a liver abscess. He previously had multiple episodes of pneumonia and a “bone infection”. What condition must you rule out?

A

chronic granulomatous disease

a male child with liver abscess (in the absence of known immunosuppression) should be considered to have chronic granulomatous disease until proven otherwise

50
Q

What other infections might you see in the child above?

A
  1. skin - superficial staph skin infections (nose, eyes, anus)
  2. lymph nodes - severe adenitis
  3. lungs - recurrent pneumonia
  4. liver - liver abscess as mentioned
    hepatomegaly is common -likely from involvement of th ereticuloendothelial system
    can get granulomas elsewhere also (i.e. in the gastric antrum)

can also have indolent osteomyelitis and chronic diarrhea

51
Q

How do you treat CGD?

A
  1. prevent infection
    - immunization, prophylactive antibiotic and anti-aspergillus, avoid pathogens i.e.: septa and itraconazole
  2. prophylactic interferon gamma (controversial)
  3. early and aggressive use of parenteral antibiotics
  4. surgery for infections
52
Q

A child presents with recurrent staph skin infections, coarse facial features and staph pneumonia . What condition do you suspect?

A

hyper IgE syndrome (autosomal recessive or dominant)
(listed as either phagocytic disorder or combined ID depending on where you look)
Clinical presentation:
1. recurrent staph infections
- skin: ie impetigo and furuncles , hard to treat
- lungs: pneumonia with abscess/pneumoatocele
2. pruritic eczematous dermatitis
3. coasrse facial features
Autosomal dominant form only has bone stuff:
- recurrent fractures and increased risk of osteomyelitis
- delayed eruption of secondary teeth
get “cold boils” no pain, heat or redness

53
Q

What lab results would you expect in hyper IgE (Job) syndrome?

A

increased IgE >2000 IU/mL (aka 20 000)
eosinophilia
abnormal cell-mediated immunity
abnormal PMN chemotaxis (on neutrophil chemotaxis assay)
autosomal dominant mutations in STAT3 or AR recessive mutation sin Dock 8
Management: treat infections, anti-staph prophylaxis

54
Q

Treatment for hyper IgE (Job) syndrome

A

e: anti staphylococcal antibiotic coverage (Oski, look elsewhere too)

55
Q

A child presents with poor growth, severe and recurrent infections, chondrodysplasia , steatorrhea , what condition do you suspect?

A

Schwachman-Bodian-Diamond syndrome:
severe neutropenia and neutrophil chemotaxis abnormalities, autosomal recessive
Diagnosis: neutropenia, genetic testing for 7q11
(**might also think of SCID depending on age/presentation, bone stuff different in the two)

56
Q

Treatment for Schwachman-Bodian-Diamond syndrome

A

pancreatic enzyme replacement

targeted antibiotic therapy

57
Q

What are the features of Chediak Higashi syndrome

A

imparied NK cell function, neutrophil chemotaxis and phagocytosis

  1. recurrent skin and resp infections
  2. severe gingivitis and periodontal disease
  3. oculocutaneous albinism
  4. easy bruising
  5. almost all develop a lymphoma-like illness by age 10 which is typically fatal

Diagnosis: giant granules in neutrophils, esosinophil and granulocytes
variable amount of neutropenia and thrombocytopenia
Treatment: bone marrow transplantation

58
Q

What is Kostman syndrome?

A

severe congenital neutropenia
autosomal recessive
severe infections starting in infancy, mortabiliy is 70% in the first hear of life (withou treatment)
severe neutropenia (ANC<200)
Treatment: GCSF, bone marrow or stem cell transplantation

59
Q

What is the allergic march

A

typical sequence of IgE development

food allergies->ezcema (late infancy) - >asthma (early childhood)->allergic rhinitis

60
Q

What are major and minor determinants against penicillin?

A

Pre-pen is a major determinant - benzyl penicillin absolutely penicillin allergic
major determinant - identifies a true anaphylactic reaction
identifies 90% of pen allergic patient
minor determinant - another type of penicillin -

61
Q

You suspect a 6 year old of having a T-cell defect. The best screen is:

A

Candida skin test is the most cost effective way to screen for T cell defects
also in secrets - read this
Secrets: skin tests for assessment of delayed-type hypersensitivity are difficult to evaluate. positive test is useful for eliminating the diagnosis of severe T cell deficiency

62
Q

true or false - steroids usually affect results of skin test

A

false - they usually don’t (but can)

63
Q

What is the most common immunodeficiency syndrome?

A

IgA deficiency

t reach adult levels until that age

64
Q

Diseases associated with increased IgE:

A 
Immunodeficiency
hyper igE
igA deficiency
nezelof
DiGeorge 
Wiscott-Aldrich
kawasaki
table 135-2 in nelson
65
Q

What are the immunoglobulins in wiscott-aldrich

A

increased igA and IgE
decreased IgM (KEY)
variable IgG
also have eczema and small platelets

66
Q

Diagnosis of ataxia telangiectasia

A

Low IgA, low IgG2, elevated AFP, definite testing is sequencing ATM gene (breakage in chromosomes 7 and 14)

67
Q

Triad with ataxia telangiectasia

A

telangiectasis not present at birth
progressive ataxia - wheelchair bound by teens
B and T cell deficiency

68
Q

Inheritance of hereditary angioedema

A

autosomal dominant

69
Q

Deficiency

A

C1 esterase inhibitor deficiency

activated complement system, cannot inactivate itself

70
Q

Clinical features of hereditary angioedema

A

clinical presentation:

  • non pitting edema, self-resolves within 3 days
  • no associated pruritus, no signs of anaphylaxis, no pain anywhere, can get some abdominal pain (edema of the bowel)
71
Q

triggers of hereditary angioedema

A

stress, OCP, pregnancies, periods, infections

72
Q

if they have a attack

A

give concentrated C1 inhibitor esterase
and can give danazol (synthetic androgen)
epi/steroids etc doesn’t work

73
Q

which immunodeficiency - bad reactions to live vaccines

A

SCID
low lymphocytes at birth
**read about SCID

74
Q

Treatment of chronic urticaria

A

start with H1 anti-histamine - cetirizine
then add H2
then try steroids on alternating days

75
Q

What are the lab tests in ataxia telangiectasia?

A

blood count - lymphopenia, increased eosinophils
reduced IgA, TgG and IgE
poor polysaccharide response
increased autoantibodies (inducing to IgA and IgG)
T cell immunity is abnormal in about 60% of patients

76
Q

What are the clinical features of SCID?

A

Secrets:

  1. recurrent bacterial infections (pneumonia, OM, sepsis)
  2. persistent viral infections
  3. opportunistic infections (PCP, pneumocystic jiroveci, fungi)
  4. failure to thrive
  5. diarrhea (entero, rotavirus)
    may include skin rash
77
Q

Main lab test for SCID?

A

CBC - to document lymphopenia (<2000/mm3)

the single most test in the initial evaluation

78
Q

How many patients with SCID will have a normal lymphocyte count

A

about 20%

79
Q

What are the four most common form of SCID

A

X linked - 50%
JAK3 deficiency - 10%
IL-7 receptor deficiency - 10%
ADA deficiency - 8%

80
Q

What are the clinical phenotypes of adenosine deaminase deficiency

A
  1. neonatal or infantile onset - 80-90%
    - lymphopenia, no hum oral or cellulr immune functions
    - FTT
    - severe infections with fungi, viral and opportunist pathogens
    * *half of them have flare ribs - abnormalities at the costochondral junction
  2. Delayed onset - 15-20%
    - recurrent infections - (sinopulmonary, sepsis, can’t generate specific antibodies)
    - increased IgE levels, IgG subclass deficiency and autoimmunity
81
Q

What diagnosis should you consider in a 3 month old infant with type 1 diabetes, severe diarrhea and eczema

A

IPEX aka
Immunodysregulation: severe colitis with cytopenias
Polyendocrinopathy: can get neonatal insulin dependent diabetes
Enteropathy
X-linked : males in the first/2nd year of life
caused by deficiency in the fork-head DNA binding protein FOXP3
Tx: immune suppression and bone marrow transplant

82
Q

Labs in the diagnosis above

A

increased eosinophils
increased IgE and IgA but usually normal T and B cells
severe diarrhea and FTT
other autoimmune features - DM1, hypothyroidism, hemolytic anemia

83
Q

What is APS1 syndrome

A

primary immune deficiency with autoimmunity
features include:
1. chronic mucocutaneous candidiasis (<15 years old)

84
Q

What is autoimmune lymphoproliferative syndrome?

A

autoimmune features in 70% of patients - include ITP, autoimmune hemolytic anemia, ITP, autoimmune neutropenia
caused by different gene defects- lead to failure of apoptosis0

85
Q

Which primary immunodeficiencies are mitochrondiopathie?

A

mitochondria in charge of apoptosis

  1. Reticular dysgenesis - a rare form (AR) of SCID
  2. Kostman disease - severe congenital neutropenia
86
Q

What should be your initial screening tests for a suspected immunodeficiency (obviously depends on the case)

A

CBC (Hg morphology, absolute cellularity), Ig levels, antibody responses to previous antigen exposures (i.e. vaccines, pathogen), determination of isohemagglutinin titers
assess complement pathway - CH50
work up of infections (i.e. CRP, cultures, X ray etc)
no need for blanket screening - only if it will affect the management of the patient

87
Q

You suspect a humoural immune system problem. Which tests will be most helpful.

A
  1. serum Ig Levels - comgined IgG, IgA, IgM level5000IU/mL for IgE - suggests hyper IgE syndrome
  2. IgG sublasses - if >6 years old in certain circumstances or if recurrent sinopulmonary infections
  3. specific antibody tigers
  4. isohemagglutinin titer 1:4 or less after age 1 years suggests specific IgM deficiency
  5. tetanus, diphtherai IgG1
  6. pneumococcal polysaccharide antigens - IgG2
  7. viral respiratory agents IgG3
  8. B cell numbers - flow cytometry CD19, CD20
  9. B cell proliferation and Ig production - in vitro assays
88
Q

Which tests help evaluate T cell functions

A
  1. total lymphocyte count (although most T cell immune deficiencies normal) <60% mononuclear cells
  2. delayed type hypersensitivity skin testing
  3. proliferative response
  4. acquisition of activation markers on T cells (using flow cytometry)
  5. cytotoxic assay
  6. cytokine synthesis
  7. aADA and purine nucleoside phosphorylase in RBCs
  8. molecular biology studies
  9. Histology of thymic and lymph-node biopsies
89
Q

What is the value of skin testing for the diagnosis of T cell deficiencies?

A

positive test - helps eliminate diagnosis of severe T cell deficiency
Negative test
– may reflect a T cell defect
- may result from lack of a response to the antigens used
Candida skin test: 75% of normal children will respond at 12-36 months, 90% by 18 months

90
Q

What is the cause of decreased CD4/CD8 ratio?of increased ratio?

A

decreased - think of HIV and other viral infections

increased - bacterial infections

91
Q

Which lab tests to evaluate the phagocytic system

A

Absolute granulocyte count
- antineutrophil antibodies
- bone marrow biopsy
Specific assays:
1. determination of chemotaxis (not routine)
2. quantification of nutrophil adherence - CD11/CD18 by flow cytometry
3. respiratory burst - NBT test ; DHR 123 test for CGD
4. enzyme assays
5. treatment with GSCF
6. mutational analysis

92
Q

How to evaluate the classic complement cascade?

A
  1. primary screening test- CH50: tests the individuals ability to lyse cells which are sensitized with rabbit IgM anti sheep antibody
    quantity of complement needed for 50% lysis of RBCs in a standardized setting
    relatively insensitive -need major changes before altered
    therefore, C3 and C4 are often also include in the initial screening of a child with a suspected complement deficiency
93
Q

What is an Arthus reaction

A

local reaction to an injected antigen
type III
large amounts of antigen leads to serum sickness- classic example of type III

94
Q

skin findings in atopy

A

baby nelson

  1. hyper linearity of the plasm and soles
  2. white dermatographism
  3. pityriasis alba
  4. creases under the lower eyelids (Dennie-Morgan folds or Dennie lines)
  5. keratosis pilaris
95
Q

Diseases associated with elevated IgE

A

pg 272 baby Nelson

  1. allergic disease
  2. atopic dermatitis (eczema)
  3. tissue invasive helminthic infections
  4. hyperimmunoglobulin E syndromes
  5. allergic bronchopulmonary aspergillosis
  6. Wiskott-Aldrich syndrome
  7. bone marrow transplant
  8. Hodgkin disease
  9. Bullous pemphigoid
  10. Idiopathic nephrotic syndrome
96
Q

Diseases associated with eosinophilia

A

(when extreme eosinophilia, suggests non allergic - i.e. infections with tissue invasive parasites, drug reactions, or malignancies

eosinophilia is 3-10% of WBC or absolute of >250 eosinophils/mm3

  1. Allergic Disease: allergic rhinitis, atopic dermatitis, asthma
  2. GI: allergic colitis, IBD, eosinophilic gastroenteritis
  3. Infectious:: tissue-invasive helminthic infections
  4. Neoplastic: eosinophilic leukemia, Hodgkin disease
  5. Respiratory: eosinophilic pneumonia, allergic bronchopulmonary aspergillosis
  6. Systemic: idiopathic hypereosinophilic syndrome, adrenal insufficiency, mastocytosis
  7. Iatrogenic : drug induced
97
Q

true or false - the presence of IgE antibodies specific are enough to diagnose an allergy?

A

false - need to look at the whole picture - i.e. physician assessment and whole picture, correlate the findings
but is a good option for those that can’t do skin testing

98
Q

side effects of inhaled steroids for asthma

A

NOT side effects at low-medium doses: HPA function, glucose, cataracts or glaucoma DON’t happen
Local effects: dysphonia and candidiasis, absorption from GI tract

99
Q

systemic side effects of multiple courses of oral steroids

A 
HPA suppression
cushingoid features
weight gain
hypertension
diabetes
cataracts
glaucoma
osteoporosis
growth suppression
100
Q

Treatment of rhinitis

A

intranasal corticosteroids - most postnet pharmacological treatment
side effects; local irritation, burning, sneezing (in 10%), nasal bleeding can happen (if spray the septum) rare cases of nasal septum perforation

101
Q

What are the two generations of antihistamines, and which are less sedating?

A

1) first generation antihistamines - diphenhydramine and hydroxizine (i.e. addax) : cross the blood-brain barrier, quite sedating; can get paradoxical reaction in younger kids; can also get anticholinergic effects
2) second generation antihistamines: cetirizine, loratadine, desloratadine, fexofenadine, levocetirizine - less likely to cross site BBB, less sedation
3) topical nasal antihistamines - aka azelestine, olopatadine - for kids > 5-6 years

102
Q

How long should you limit use of nasal decongestant spray?

A

5-7 days to prevent rebound nasal congestion

103
Q

what percentage of kids with moderate to severe atopic dermatitis will have food allergies

A

35-40% will have food allergies

egg allergies is the most common cause of food-induced eczematous reactions

104
Q

medications that should be avoided by a person with anaphylaxis

A

beta blockers
ACE inhibitors
monoamine oxidase inhitors - d/c because they might worsen anaphylaxis or interfere with treatment

105
Q

labs in serum sickness

A 
baby Nelson) 
increased ESR
circulating immune complexes
depressed complement - C3 and C4 levels
skin biopsy might show immune deposits of IgM, IgA, IgE or C3
hematuria or proteinuria or both

Allergy and Immunology (2 decks)

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