Immunology Flashcards
How do you diagnose an allergy in the lab?
IgE serology
Allergen Specific IgE ( immunocap assays )
What are the immunocap allergen mixes?
① aero allergen mix (7 )
• cockroach
• dust mite
• Grass
• dog
• cat
• aspergillas tumigata
• alternaria alternata
② food mix (6)
• peanuts
• cowmilk
• soy bean
• wheat
• egg white
• fish
How do you differentiate a true peanut allergy?
Presence of Ara h 1, 2, and 3 specific IgE
Define immunodeficiency
Immunodeficiency is the result of a diverse group of abnormalities of the immune system resulting primarily in an increased incidence of infection.
What are the 10 warning signs of primary immunodeficiency? NB
1) positive family history
2) 2 or more months on antibiotics with little effect
3) 8+ new ear infections in one year
4) 2+ serious sinus infections in 1 year
5) 2+ pneumonias in 1 year
6) failure to gain weight/grow normally
7) recurrent deep skin/organ abscesses
8) 2+ deep seated infections
9) persistent thrush in mouth or other after age 1
10) need for IV antibiotics to resolve infections
How do you screen for PID (primary immunodeficiency disease)
History: SPUR
S erious infections needing AB
P ersistant infections
U nusual organisms
R eccurent infections
Lab tests
1) FBC and diff
2) total serum immunoglobulins (Ig G,A, E, M) and IgE subclasses
3) Total haemolytic complement (C3+C4)
4) Flowcyto analysis of Tcells, B-cells, NK cells
What are limitations of serological procedures?
1) Antibodies not always produced
2) high pre-existing antibody levels
3) many antigenic subtypes for some pathogens
When do we use serodiagnosis
1) HIV
2) rickettsia (tick bite)
3) syphillis
4) Chlamydia
5) toxoplasmosis
How do you tell the difference between acute and chronic disease by serology?
Chronic has IgG 4 fold above the basal. Increased titres must be shown in follow up tests 4-6 weeks later.
What antibody is the mainstay of chlamydia infection?
IgA
What serological procedures do we use to detect antibodies?
1) Indirect immunofluorescence - add anti human antibody and look under microscope
2) enzyme linked immunoassay- anti human antibody added = colour change if antigen present (measured by spectrophotometer)
Tick bite fever - how do you use serology to tell if it’s acute or chronic?
Phase 2 titres > Phase 1 titres = acute
Phase 1 titres > phase 2 titres = chronic
What is central tolerance?
Tolerance mechanisms that operate in the thymus before the maturation and circulation of T cells
Requirements for a autoimmune disease?
Genetic factor + infection/environmental exposure = immune regulation →autoimmunity
What is the incidence of autoimmune diseases?
8% of the population, 78% of which are female
