Deficiency in Adaptive Immunity (complete) Flashcards
Describe generally primary immunodeficiencies
- Means a disease probably has a genetic cause
- Ask yourself: does it exist at birth or not? (Congenital)
- Ex: if thymus were congenitally dysfunctional
Describe generally secondary immunodeficiencies
- Some known process outside the immune system caused the deficiency
- Think: ACQUIRED
- Ex: HIV, measles, malaria, EBV
What types of infections would you see with pure B cell deficiency?
- High grade EXTRACELLULAR bacterial pathogens (e.g. Staph, H flu, Stept)
- Just think about the type of immune response that involve B cells
What types of infections would you see with pure T cell deficiency?
- Intracellular pathogens (viruses, certain bacteria, yeasts, fungi)
- Just think about the type of immune response that involve T cells :D then you got it!
Describe the clinical features which are part of DiGeorge syndrome, excluding immunological features
1) Hypertelorism
2) Down-slanting eyes
3) fishmouth deformity
4) Micrognathia
5) Low-set ears
Discuss the incidence of IgA deficiency. What are the associated syndromes?
1 in 500 — most common immunodeficiency disease
10x more frequent in people w/ celiac
1) Diarrhea
2) Sinopulmonary infections
3) Increased frequency/severity of allergies
Describe the immunological problem of the Nude mouse. What is the human immunodeficiency condition it resembles?
- Have a genetic mutation and have no thymus, can’t make the stroma —-» no T cells
- Also have no hair
- Very similar to DiGeorge Syndrome, but it’s a different mutation
These mice reject grafts b/c there are no T cells — all around very useful for research
What is the enzyme absent in certain cases of SCID?
Adenosine Deaminase
Discuss possible approaches to replacing adenosine deaminase
1) Enzyme replacement therapy
2) Blood transfusions of irradiated red cells (RBCs have ADA— radiation gets rid of remaining B/T cells)
3) Purified stem cell transplant (otherwise potential for GvH)
Discuss transplantation therapy in immunodeficiency diseases. What are some complications?
Always potential for GvH disease
- BM transplant has 50% success rate in SCID — purified stem cells are preferred to avoid GvH
What are the principle tests for determining a B cell deficiency?
1) Serum protein electrophoresis
2) Quantitative IgG, IgA, IgM levels
3) Specific Abs to prior immunizations
4) ABO isohemagglutinins
What are the principle tests for determining a T cell deficiency?
1) Skin test w/ recall Ag panel
2) Total lymphocyte count
What are the principle tests for determining a phagocyte deficiency?
1) WBC count, differential, morphology
2) NBT test – oxidative burst
What are the principle tests for determining a complement deficiency?
1) CH(50)
2) Assay for C1inh (inhibitor)
Where in the lymph node are B cells located?
Germinal Centers
Where in the lymph node are T cells located?
Paracortex
Describe the contents of IVIG
Aka: Human Immunoglobulin
- about 99% IgG
- It’s donated by lots of people
Describe the routes of administration for IVIG
- IV use — effective, expensive; often in short supply
- SC use — can be done at home
For which conditions would IVIG be useful as replacement therapy?
Those w/ B cell deficiencies
Eg:
- Bruton
- SCID
- HyperIgM
- CVID
What are 2 viruses which are immunosuppressive in humans?
1) Measles
2) Mono
3) CMV infection
4) AIDS
Describe Severe Combined Immunodeficiency Disease
- T and B cell deficient
- Block in development of lymphoid stem cell
- X linked: defect in gamma chain —» IL-2 receptor problems
Describe X-linked (Bruton)n agammaglobulinemia
- Normal T cells
- Low to absent B cells
- Due to developmental block btwn pre-B cells and B cells — most pts have pre-B cells in BM, but deficient in mature B cells
- IgG has less than 10% of normal, no IgA or IgM
- This is why OPV isn’t used in the US
Describe X-linked hyperIgM syndrome
- It is how it sounds
- Too much IgM w/ low IgG and IgA
- Defect in IgM-to-IgG switch mechanism
Describe Common Variable Immunodeficiency (CVID)
- Normal #s of pre-B and mature B cells
- Difficult to trigger to make a specific Ab — IgG is low
- Can be diagnosed for the first time in pts up to 50yo
- Main phenotype: recurrent bacterial infections
- Tx: IVIG, SCIG
- Causes: unknown
