Immunology Flashcards
If your NK cell function was compromised, what pathogens would you be at risk for infection from?
Viruses (esp DNA viruses)
Decreased CD3/CD4 and CD3/CD8 T cells increases your risk of what type of infection?
Viruses
Pneumocystis
Fungi
Decreased B cells would increase your risk of what type of infection?
bacteria (esp encapsulated)
Decreased neutrophils increases your risk of what types of infections?
bacterial
fungal
list two risk factors for infection pre-engraftment (day 0-30) and what infections they are at risk for
profound neutropenia and a CVL
risk of bacterial infection, candida, aspergillus, HSV, respiratory viruses
list risk factors for infection post-engraftment (day 30-100) and what infections they are at risk for
lymphopenia (esp CD4 t cells), on t cell suppressive meds, CVL
aGVHD
risk of: bacterial infections, aspergillus, CMV, respiratory viruses, EBV reactivation, PCP, toxoplasmosis
list risk factors for infection post-engraftment (late > 100) and what infections they are at risk for
lymphopenia (CD4), t cell suppressive meds, cGVHD, poor Ig production
risk of: encapsulated organisms (esp if functional asplenia), aspergillus, VZV, CMV, EBV, PCP, toxo, resp viruses
bacterial infections in immunocompromised hosts are:
from endogenous flora (gram neg rods from gut, gram positive cocci, anaerobes)
high-dose cytarabine is associated with what infectious complication
alpha-hemolytic strep (s.mitis, s. sanguis) with ARDS and rapidly evolving sepsis syndrome
spleen is the site of what types of b cells?
marginal zone b cells - respond to polysaccharide antigens
if asplenic, what vaccines do you need?
pneumococcus, HiB, meningococcus
risk factors for fungal infections
prolonged neutropenia
CD4 lymphopenia
prophylaxis for candidiasis?
fluconazole (azole) or caspofungin (echinocandin)
risk factors for pneumocystis jirovecii
CD4 count < 200
prolonged neutropenia
immunocompromised
steroid treatment
alternatives to septra?
atovaquone
dapsone
pentamidine (IV, inh)
clindamycin plus primaquine
treatment for CMV infection
ganciclovir
valganciclovir
foscarnet
cidofovir
treatment of HSV
acyclovir
foscarnet
how long after exposure to HSV can you administer VZIG?
up to 96 hrs post
treatment in immunocompromised host for HSV?
acyclovir
what cells are considered lymphocytes? what are their characteristic cell surface markers?
CD16/56 - NK cell (innate imm)
CD4 - helper T cell
CD8 - killer T cell
CD19 - B-cell
what MHC class do CD4 t cells recognize?
MHC class II
function of CD4 t cells
class switching of b cells
antigens characterizing pre-B cells
CD 19
CD 10
loss of CD 34
(no CD20 until later)
testing function of t cells
proliferation to mitogens (phytohemagglutinin, PWM, conA)
proliferation to antigen (candida)
testing function of b cells
measuring immunoglobulins
measuring specific antibodies (ie, vaccine titers, blood group)
antibody production requires intact t cell function
which immunoglobulin is transfered via placenta
IgG (monomeric - small)
physiologic nadir in immunoglobulin (IgG) levels
2-6 months
what is absent in SCID?
t cells
condition without b cells?
x-linked agammaglobulinemia
failure of t cell development
SCID
how to diagnose scid?
check lymphocyte count
check lymphocyte subsets
lymphocyte proliferation studies (low proliferation to mitogens)
T-B+ SCID caused by what mutations
cytokine common gamma chain
JAK3
IL-7 receptor alpha chain
lack of what receptor leads to absence of T cells
IL-7R
lack of what receptor leads to absence of NK cells
IL-15R
how can a baby with SCID have t-cells?
from maternal engraftment
x-linked agammaglobulinemia - gene involved?
bruton’s tyrosine kinase (BTK) gene
X linked agammaglobulinemia - what is pathophysiology?
mutation in BTK gene resulting in arrest of b-cell development at pre-B stage - absence of peripheral b cells
how does XLA present?
the boys have maternal IgG so don’t present until 6-9 months with infections
what infections are boys with XLA at risk for?
chronic enteroviral meningoencephalitis - avoid live vaccines
diagnosis of XLA
absence of CD19 cells, low immunoglobulins
WAS
x-linked
deficiency of WASP protein
triad: immunodeficiency, eczema, small platelets (MPV 4-5)
may also have high IgE
WAS defect
combined T and B defect numbers may be normal function abnormal - lacking carbohydrate responses (isohemagglutinins, pneumovax)
