Allergy and Immunology Flashcards
Describe the innate immune system
Includes complement, macrophages and NK cells. Nonspecific, rapid acting and no memory
Describe the adaptive immune system
T and B cells and immunoglobulins. Much slower, very specific and has memory
What are the two major functions of t cells
1.) Destroy intracellular and other bacteria, viruses, fungi, parasites and mycobacteria 2.) The regulate antibody production by B cells
When do CD8 t cell recognize an antigen
If presented with HLA class I antigen
When do CD4 t cell recognize an antigen
If presented with HLA class II antigen
CD2+ and CD3+
t cells
CD19+ and CD20+
b cells
CD16+ and CD56+
NK cells
What do CD8+ t cells do?
cytotoxic to viruses and neoplastic cells
Which immunoglobulins can activate the complement pathway?
2 IgGs or 1 IgM pentamer. Activate the classical pathway.
Wiskott-Aldrich syndrome
x linked, eczema, thrombocytopenia and immunodeficiency
What is Bloom syndrome
Similar to ataxia-telangectasia in that it is a “chromosomal instability syndrome. Small stature, telangectasia, CNS abnormalities, immunodeficiency. High association with leukemia
What is x linked lymphoproliferative disease or Duncan syndrome?
x linked lymphoproliferative disease that cuases severe infeciton with EBV causing hepatitis, B cell lymphoma, agrnulocytosis, aplastic anemia. EBV triggers polyclonal expansion of T and B cells - those who survive are Antibody deficient.
Kostmann Syndrome
AR familial severe neutropenia. Treat with GMSF
Which situations should you not give give live attenuated vaccines to household contacts
kids with SCID, avoid live flu and VZV to household contacts.
Can kids with HIV gets live vaccines
If not severely immunocomp can get MMR and VZV at 12 months
Type 1 hypersensitivity
IGE mediated, immediate (anaphylactic, atopic)
Type 2 hypersensitivity
IgG mediated, cytotoxic
Type 3 hypersensitivity
Immune complex mediated
Type 4 hypersensitivity
cell -mediated
What are examples of non IgE anaphylaxis?
NSAIDs, asa, physical stress can cause the release of cytoplasmic granules from mast cells
How much epi is in Epipen and Epipen Jr?
Epipen = 0.3mg for pt>30kg, Epipen Jr = 0.15mg for pts
What is the concentration of IV epi vs IM epi
IM epi is 1:1000, 1mg/ml; IV is 1:10000, 1mg/10ml
Cutaneous mastocystosis
rare disorder of increased mast cells in dermis causing urticaria pigmentosa which is diagnosed by formation of a wheal upon gentle stroking of a macule
Systemic mastocystosis
Increased mast cells in skin and tissue. Have abdominal symptoms, flushing and fatigue in addition to urticaria pigmentosa
Malignant mastocytosis
severe systemic symptoms but no skin changes. HSM and LAD. Elevated tryptase levels >20, BMB indicated
which stinging insect is most likely to cause anaphylaxis?
yellow jacket
episodic swelling at areas of trauma without pruritis, but with AD inheritance suggests what?
Hereditary Ci inhibitor deficiency. A function defect in C1 inhibitor consumes C4 continuously. Screen by checking C4 first
What does urticaria after swimming suggest?
cold urticaria. There is no allergic component, an ice cube test confirms the presence of cold urticaria
What fruits most often cross react with latex allergy?
banana, avocado, kiwi, chestnut
What is oral allergy and which foods are most often implicated?
aka pollen-food allergy syndrome, is an IgE mediated condition that mostly affects the oropharynx. 2/2 cross reactivity between proteins in pollens and fresh fruits and vegetables.
by how much can venom immunotherapy reduce the risk of a subsequent reaction?
to
Is immunotherapy effective for hypersensitivity to foods?
No
If a patient has hypotension, uritcaria, itching with radiocontrast dye, can they get it again?
This is likely not an IgE reaction. Most likely due to mast cell mediated mechanism. High risk patients should get prednisone and antihistamines - can decrease the risk to 1%
What is type 3 hypersensitivity?
serum sickness - can be mediated by IgG or IgM antibody- antigen complexes. Can be deposited in various organs and activate the complement system.
What amount of steroid prevents giving live attenuated vaccines
20mg/d or more for 14 days. Must wait one month after going off of it to give live vaccine
Who needs irradiated blood
patients with defects in cell mediated immunity - SCID, DiGeorge, post transplant. They are at risk for GVHD when they receive nonirradiated products containing immunoreactive t cells from unmatched donors
What are risk factors for persistent asthma
smoke exposure, obesity and early menarche in girls, maternal age less than 20 at time of birth
What can decrease the risk of asthma
breast feeding for at least first 4 months, avoiding allergenic pets, avoid smoke exposure, reducing multiplle allergens
What percent of asthma persists into adulthood
25-75%
What percent of patients with allergic rhinitis will get asthma?
20% over 10 year f/u
What percent of patients with asthma will get allergic rhinitis?
85%
What is the difference between percutaneous and intradermal skin testing
intradermal is more sensitive, but less specific, more painful and higher risk for anaphylaxis. Used for hymenoptera venom sensitivity
which meds need to be stopped before skin testing?
omalizumab, antihistamines, H1 and H2 blockers, strong topical corticosteroids, TCAs
What is food protein induced enterocolitis syndrome
secondary to cows milk and soy. Presents at 1-3 months. Chronic severe symptoms: V/D, melena, FTT, acidosis, methemoglobin, toxic appearance; if stop causive food, symptoms resolve, recur with reintroduction. Resovles by 2-3 years but must rechallenge in the hospital
What is better for suspected food allergy, RAST or skin testing?
skin testing has low PPV, RAST can identify 95% of patients with food allergy. Negative test of each makes allergy very unlikely. Immunotherapy not effective for food
are air filters helpful for dust mite exposure prevention?
no because they are heavy and does not remain suspended for long. (however HEPA air filters help for dog hair)
Does skin allergy testing help in chronic urticaria?
No a positive skin test in a patient with chronic urticaria does not necessarily mean that is the cause of the chronic urticaria.
If you have a shellfish allergy, do you need to worry about contrast allergy?
No, even though both have iodine, this is a myth. RCM reaction is not IgE mediated either. No need for pretreatment
If a patient had a life threatening allergic reaction should you do skin or RAST?
RAST
Tell me about allergy testing for hymenoptera
25% false negative rate for both skin and RAST. Therefore if one is neg, go to the other. The testing should be done 4-6weks after the reaction to be reliable
Do you have to stop antihistamines for RAST testing?
No
In which patients is specific immunotherapy contraindicated?
Specific immunotherapy is contraindicated in patients with cardiac disease. Other conditions that should induce caution when using SIT include autoimmune conditions, immunodeficiency syndromes, and malignant disease
which deficiency is associated with early onset SLE?
C2 deficiency
Ataxia-telangestasia
AR disorder - ataxia early in life, telangectasia 5 years of age, elevated alpha -1 feta protein, multiple infections
Job syndrome
hyper -IgE syndrome. asymmetric face, broad nose, traingular jaw, eczema, scoliosis, hyperextensible joints, recurrent cold abscesses, eosinophilia
