Defects In Activation Of T Cells Flashcards
What is common gamma chain deficiency?
T-B+NK-
IgM+, low everything else
X linked recessive
Defect in gene encoding gamma chain which is shared by IL-2R
Pts with common gamma chain deficiency present with what?
Failure to thrive, severe thrush, opportunistic infections and chronic diarrhea
With which deficiencies should live/viral vaccines be avoided?
Common gamma chain, IL-7R alpha chain, BLS II and CD3 deficiencies
For which deficiencies is HSCT appropriate?
Common gamma chain, IL-7R, BLS II, CD3 complex deficiency and IPEX
What is IL-7R alpha chain deficiency?
T-B+NK+
IgM+, low everything else
No costimulation from T cell to B cells
Pts present with cadidiasis, chronic diarrhea, pneu jiroveci and severe viral infections during infancy
What is bare lymphocyte syndrome II (BLS II)?
Normal Ig levels
No MHC class II expression on APCs resulting in CD4 deficiency
Leads to recurrent respiratory, GI and UTIs, death in childhood
What is MHC class I deficiency?
CD8 low and normal Ig levels
Caused by mutation in TAP molecules to transfer peptides to the ER
Recurrent viral infections
Symptomatic Tx, no vaccine restrictions
What is CD3 complex deficiency?
T-B+NK+
IgM+, low everything else
Presents in infancy w/ lymphopenia, decreased T cell #s, failure to thrive, chronic diarrhea and opportunistic and viral infections
Specific Ab responses decreased
What happens in pts with IPEX?
Self reactive effector T cells aren’t inhibited because of a mutation in FOXP3
Tx = HSCT
What happens in pts with ALPs?
Defects in either Fas/FasL, caspase 8 or 10 genes results in abrogated formation of death induced signaling complex (DISC) and resistance of effector T cells to apoptosis
HSCT not recommended
What is Wiskott-Aldrich syndrome (WAS)?
T-B+NK-
Low IgM, normal IgG, high IgA and IgE
X liked disorder characterized by thrombocytopenia, eczema, cellular and humoral immune deficiency, autoimmune disease and malignancy
Caused by mutations in the WAS protein (WASP)
Describe pts with WAS
They develop a combined immunodeficiency with low IgM, normal IgG and high IgA and IgE, T cell lymphopenia and decreased NK cell cytotoxicity
Have recurrent bacterial infections with encapsulated bacteria, viral infections and opportunistic infections with jiroveci and candidiasis
Pts with defects in the IFN-gamma and IL-12 axis loop present with what?
Selective susceptibility to intracellular pathogens such as atypical mycobacteria, candida and salmonella
What is Th17 deficiency?
Susceptibility to mococutaneous candidiasis
Associated with mutations in genes encoding for IL-17, IL-17R, TF STAT 1, 3 or AIRE
Many pts with Th17 deficiency are characterized as having what?
Autosomal recessive hyper IgE syndrome with severe atopic disease (atopic dermatitis, food allergies and asthma) as well as recurrent staph aureus skin abscesses