Assays for Immune Function Flashcards
CBC with diff
- number of cells
- check morphology of cells
general markers of inflammation
- ESR; erythrocyte sedimentation rate (sed rate)
- CRP; c-reactive protein
chemistry panel
- check organ systems
- can include urinalysis
first step in eval of antibody deficiency/defects
- measure total IgG, IgA, IgM
- check normal range
pattern of abnormality important for
- specific immune deficiency
measurement of IgG subclasses and/or IgE subclasses
- may be useful depending on presentation
when do you check IgD?
- only if periodic fever
- not immune deficiency
next step if any antibody deficiency is confirmed
- consider B cell quantitation
most common immune deficiency
- selective IgA deficiency
normal quantity does not always equal
- normal function
assays for antibody function
- antibody titers to specific pathogens
titer to vaccine
- known exposure
- diphtheria/tetanus titer
response to polysaccharides
- pneumococcal titers in older children given the polysaccharide vaccine
isohemagglutinins
- antibodies generated in response to polysaccharides of glut flora
- cross react with A or B blood group erythrocyte antigens
low IgG levels - something to consider
- protein loss as cause
what is always the first step
- CBC with differential
what do you need to check if you have lymphopenia?
- primary versus secondary
- which lymphocytes are low
use of flow cytometry important for?
- quantitating lymphocytes
- can also tell what lymphocytes are present
CD3 marker for which cell type
- T cells
CD4 marker for which cell type
- helper T cells
CD8 marker for which cell type
- Cytotoxic T cells
- also 1/3 NK cells
CD19 marker for which cell type
- B cells
CD16/56 marker for which cell type
- NK cells
limited lymphocyte markers testing
- CD 3, 4, 8
complete lymphocyte markers testing
- all
T cell function assays
- in vitro assay of T cell function
T cell function assays measure
- peripheral T cell proliferation in response to varied types of stimuli
T cell function assays use what proteins?
- mitogens such as phytohemagglutinin, concanavalin A, and pokeweed mitogen
extent of proliferation
- measure the radioactivity taken up by cells
cutaneous delayed type hypersensitivity test
- class in vivo test of cellular immunity
cutaneous delayed type hypersensitivity test - how it works
- intradermal injection of antigen to which the individual has been exposed
cutaneous delayed type hypersensitivity test - positive response requires
- uptake and processing of antigen by antigen presenting cells
- interaction with CD4 cells
- cytokine production
- recruitment and activation of monocytes and macrophages
cutaneous delayed type hypersensitivity test example
- PPD
neutrophil defects initial test
- CBC with differential
neutrophil defects initial test - if neutrophils numbers are normal and a neutrophil defect is suspected
- tests of function should be ordered
how to measure neutrophil oxidative burst
- nitroblue tetrazolium test (NBT)
- flow cytometry
serum IgE
- hyper IgE syndrome
giant azurophilic granules are seen in granocytes of persons with
- Chediak-Higashi syndrome
complement defects - initial screening test
- total hemolytic complement (CD50)
total hemolytic complement measures
- assessment of classical pathway
if total hemolytic complement test significantly reduced
- specific complement components can be assessed
if total hemolytic complement test is normal but a complement deficiency is still suspected, what test do you run?
- tests for AH50 - screening test for alternative pathway defects
alternative complement deficiencies include
- properdin and factor D deficiencies
- exclude mannose-binding lectin defect
