Immunodeficiency Flashcards Preview

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Flashcards in Immunodeficiency Deck (32):
1

When should immune evaluation be considered?

two or more invasive bacterial infections, persistent or recurrent sinopulmonary infections, unusual etiologic agents or unusual severity of common infection

2

What are some physical examination findings that may indicate immunodeficiency?

less growth/development, enlarged/absent tonsils, nodes, liver, spleen, thrush, rash

3

What are the four limbs of the immune system?

cellular immunity, humoral immunity, complement, phagocytes

4

What is the most common immunodeficiency?

selective IgA deficiency, can be asymptomatic

5

What is severe combined immunodeficiency? What is the prognosis? (SCID)

no T cells or B cells, early death without BM transplant

6

What causes SCID?

IL-2 gamma chain defect

7

Why does a IL-2 gamma chain defect cause immunodeficiency?

IL-2 gamma chain is the critical signal transduction component of the IL-2 receptor

8

What signals can no longer be processed if there is an IL-2 gamma chain defect?

B-cell maturation, NK cell development, hematopoises, T-cell development, class-switch, peripheral T cell homeostasis signals

9

How can you diagnose SCID?

lymphopenia, analysis of lymphocyte proliferation in response to mitogens, non-self HLA antigens in mixed lymphocyte culture or specific antigens (would have to know hx of what they should be responsive to), thrush

10

What are mitogens? What are 3 examples?

plant lectins that bind to sugars on cell surfaces, crosslink them, and stimulate T cells and B cells
-PHA, conA, pokeweed

11

What occurs in mixed lymphocyte culture?

Look at proliferation of self lymphocytes in response to irradiated stimulating lymphocytes (that will not proliferate), tests reaction to non-self HLA

12

Why is it important to know the history of patient exposures for lymphocyte proliferation analysis?

for testing specific antigens, need to know if they should be responsive to it

13

What are treatments for SCID?

aggressive Abx and antivirals, BM transplant, replacement Ig (half-life of 2-3 weeks)

14

What is the most common presentation of humoral immunodeficiency?

respiratory infection or unusual enteric infection from lack of IgA or increased severity of a usually not severe infection

15

What causes X-linked agammaglobulinemia?

absence of B-cells due to mutation in Bruton's tyrosine kinase, cannot mature

16

What does a CD40L deficiency result in for humoral immunity? cell-mediated immunity?

hypo-IgG/IgA with hyper-IgM, can't class switch because need CD40L-CD40 interaction with T cell for IL-4 stimulation of B cell, no germinal centers in lymph nodes, macrophages will not be activated

17

What type of infections is there an increased risk for with humoral immunodeficiency?

encapsulated pathogens, esp. pneumococci, chronic enterovirus meningoencephalitis

18

What type of immunodeficiency leads to increased risk for lymphoma? Why?

humoral, lack of T cell and B cell interactions leads to tumors

19

What Ab deficiency has a defect in producing Ab to polysaccharide antigens?

selective IgA

20

What would cause increased susceptibility to Neisseria meningitis or gonorrhea?

complement immunodeficiency

21

How can you treat complement deficiency?

vaccinate against meningococcus since B cells are normal and will produce antibodys, treat pts with antibiotic prophylaxis

22

What indicates a phagocyte deficiency?

fungal infection, unusual suppurative infection, chronic granulomatous disease

23

What is the most common qualitative neutrophil defect called? What is it?

chronic granulomatous disease, eats the bacteria but isn't generating an oxidative burst so it forms a granuloma, need activated macrophage to kill bacteria

24

What is NBT reduction assay?

when put the clear solution on activated neutrophils it turns into blue crystals
if it stays clear the neutrophils aren't work right

25

Where is the risk for infection higher with phagocyte deficiency, in catalase positive or catalase negative bacteria?

catalase positive- they get rid of the peroxide they generate and rely on phagocyte to give oxidative burst
catalase negative bacteria make peroxide that is not broken down further so it can build up in phagosome and help kill bacteria over time

26

How do you treat phagocyte deficiency?

antibiotic prophylaxis, early identification and treatment of infections, IFNgamma to activate macrophages

27

What is DiGeorge's syndrome?

abnormal embryonic development of the 3rd and 4th pharyngeal pouches, congenital thymic hypoplasia/aplasia (no maturation of Tcells), and hypoparathyroidism (abnormal calcium levels)

28

What are infection risks for cellular immunodeficient patients?

viral and fungal diseases

29

Why do you use irradiated blood products for cellular immunodeficient patients?

T cells can come in on blood products and attack host tissues, irradiate the blood product to kill those T cells

30

Why is there some improvement in cellular immune function over time?

more extrathymic maturation of T cells as you age

31

What cells do HIV target?

CD4+ T cells, macrophages (but not killed)

32

What malignancies are associated with HIV?

Kaposi's sarcoma, lymphoma, squamous cell carcinoma