Lecture 7 - Immunodeficiencies

Question 1

what are the 4 mechanisms of immune effector strategies?

Answer 1

complement, neutrophils, B cells and T cells

Question 2

what does the early stage of an immune response involve?

Answer 2

cytokines, interferons and IgM

Question 3

what are the secondary immune response molecules?

Answer 3

dendritic cells, Nk cells

Question 4

what are the final immune response molecules?

Answer 4

immune response of T cells and B cells

Question 5

what are the features of primary immunodeficiency?

Answer 5

usually genetic, X-linked of autosomal, rare, biochemical abnormality

Question 6

what are the features of secondary immunodeficiency?

Answer 6

external influences on cells, due to viral infections, chronic infections, malignancy, radiation, toxins

Question 7

what are the warning signs of immunodeficiency?

Answer 7

eight or more new infections in 12 months or 2 new sinus infections in 12 months, two+ months on antibiotics with little effect, complication with a live vaccination, family history

Question 8

what are the secondary indications of ID?

Answer 8

bone marrow transplant, biological therapy, chemotherapy causing immunosuppression

Question 9

what are the useful first line investigations?

Answer 9

FBC, immunoglobulin levels in the blood, complement levels, response to a vaccination, lymphocyte population analysis

Question 10

how are immunoglobulins measured?

Answer 10

nephelometry

Question 11

how does nephelometry work?

Answer 11

input of purified and clear anti-Ig (antiserum) to the patients serum and measure the turbidity to determine binding

Question 12

how is complement activity measured?

Answer 12

gel contains sheep blood cells with rabbit antibody, lysis via complement causes clear zone in the gel so can measure complement activity

Question 13

what complement deficiencies cause bacterial infections?

Answer 13

C3 and factor B

Question 14

what complement deficiencies cause severe systemic lupus?

Answer 14

C1, C4, C2

Question 15

what is the protein vaccine used for immunisation response?

Answer 15

tetanus toxoid

Question 16

what is the polysaccharide vaccines?

Answer 16

pneumovax and haemophilia influenzas type B capsular polysaccharide

Question 17

what type of vaccines do children not respond too? what is used instead?

Answer 17

polysaccharide vaccines and so Prevnar used

Question 18

how is immunisation response measured?

Answer 18

take some serum after vaccine to carry out an ELISA to test for antibody presence

Question 19

how are lymphocyte populations identified?

Answer 19

using CD markers and monoclonal antibodies

Question 20

what CD markers does T lymphocytes have?

Answer 20

CD3 and CD4/8

Question 21

what CD markers does T lymphocytes lack?

Answer 21

CD19 and CD56

Question 22

what is the first step in evaluating a sample?

Answer 22

a full blood count

Question 23

how do you confirm a FBC result?

Answer 23

T, B, NK tests

Question 24

what is the percentage T sum?

Answer 24

the difference between CD3 and CD4+CD8

Question 25

what should the percentage T sum be?

Answer 25

less than 5%

Question 26

what should the CD4/8 ratio be?

Answer 26

around 2

Question 27

what CD marker is used for T cells?

Answer 27

CD3

Question 28

what CD marker is used for B cells?

Answer 28

CD19

Question 29

what CD marker is used for NK cells?

Answer 29

CD56

Question 30

what are the advantages of immunophenotyping?

Answer 30

rapid, small sample, whole blood analysis, lots of info on small sample

Question 31

what are the limitations of immunophenotyping?

Answer 31

needs to be fresh, rarely sufficient for diagnosis

Question 32

why might problems arise with immunophenotyping?

Answer 32

different antibody specificities, mutations may be in part of molecule undetected by antibody

Question 33

when are lymphocyte extended panels used?

Answer 33

under 5 years old

Question 34

when are B cell panels used?

Answer 34

adults where globulin levels are low

Question 35

what is a monocyte extended panel?

Answer 35

whole blood incubated with antibody panel for 20 mins with coloured antibodies, red cells lyse, samples washed and resuspended then analysed on flow cytometer

Question 36

what CD are monocytes?

Answer 36

CD14

Question 37

what is expressed on monocytes and B cells?

Answer 37

HLA-DR

Question 38

what HLA is expressed on T cells?

Answer 38

HLA-DA

Question 39

what are naive T cells positive for?

Answer 39

CD3, CD4, CD45, CD27

Question 40

what are the signals required for T cell activation?

Answer 40

T cell recognising antigen on MHC, CD28 on TC binds to CD80 on APC and cytokines provide a third signal for full activation

Question 41

what is used in order to carry out a proliferation assay?

Answer 41

peripheral blood and mononuclear cells which will contain B and T lymphocytes

Question 42

how are the mononuclear cells obtained from blood sample?

Answer 42

diluted and centrifuged, mononuclear cells form at interphase so pipetted off to be counted

Question 43

how is DNA levels measured in proliferation assay?

Answer 43

3H-thymine added and incorporated and beta counter assess the level of isotope

Question 44

what are the issues with proliferation assays?

Answer 44

use of isotope, exposure to radiation, disposal of radioactive waste, does not indicate which cells are proliferation

Question 45

how does a flow based proliferation assay work?

Answer 45

CFSE diffuses into cells and becomes fluorescent when acetate groups removed by esterase's, this fluorescence decreases with each cell division, to then be plotted on a graph of cells vs fluorescence

Question 46

what is intracellular protein staining?

Answer 46

activate T cells and prevent protein export, cytokines build up inside and antibodies diffuse inside, binding to the cytokines

Question 47

what is chronic granulomatous disease?

Answer 47

defect in phagocytic NADPH oxidase function which reduces activity of the enzyme, therefore unable to create oxygen intermediates to kill bacteria