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22 Cards in this Set
- Front
- Back
The pharyngeal apparatus is first observed in what week of development?
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Week 4
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DiGeorge syndrome is?
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Developmental failure of the third and fourth pharyngeal pouches. Due to 22q11 microdeletion. Presents with T-cell deficiency (lack of thymus); hypocalcemia (lack of parathyroids); and abnormalities of heart, great vessels, and face
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SCID is?
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Severe Combined Immunodeficiency.
Defective cell-mediated and humoral immunity. Etiologies are many. |
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What are some important causes of SCID?
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(1) Cytokine receptor defects.
(2) Adenosine deaminase (ADA) deficiency. (3) MHC class II deficiency (for CD4+ helper activation and cytokine production). |
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SCID is characterized by a susceptibility to [...]?
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Everything. Fungal, viral, bacterial, protozoal infections. They are susceptible to opportunistic infections and also live vaccines.
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Treatment of SCID?
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Sterile isolation ("bubble baby") and stem cell transplantation.
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What is X-linked agammablobulinemia?
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Complete lack of immunoglobulin due to disordered B-cell maturation. Pre-B cells cannot mature to mature B-cells. Due to a mutated (Bruton's) tyrosine kinase.
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How does X-linked agammaglobulinemia present?
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Presents after 6 months of life with recurrent bacterial, enterovirus (e.g., polio and coxsackievirus), and Giardia lamblia infections; maternal antibodies present during the first first months of life are protective.
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What must be avoided (like in SCID) in X-linked agammaglobulinemia?
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Live vaccines (e.g., polio).
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What is CVID?
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Common variable immunodeficiency. Low immunoglobulin due to B-cell or helper T-cell defects (B-cells to plasma cells).
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In CVID you would be susceptible to?
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Increased risk for bacteria, enterovirus, and Giardia lamblia infections, usually in late childhood. ALSO, increased risk for autoimmune diseases and lymphoma.
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This is the MC immunodeficiency. What is the problem and what are patients susceptible to?
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IgA deficiency. Low serum and mucosal IgA. Increased risk for mucosal infection, especially viral; however, most patients are asymptomatic.
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Hyper IgM-syndrome is characterized by _________.
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elevated IgM
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Hyper IgM-syndrome is due to? What is the main problem with this disease?
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Mutated CD40L (on helpers) or CD40 receptors (on B-cells).
There are two ways in which B-cells get activated: (1) Naive B-cell with monomeric IgM gets directly activated (antigen) --> IgM secreting plasma cell (2) Antigen is internalized and presented on MHC II. Helper binds MHC II. CD40 stimulus is second signal. IL-4, IL-5 from helper will hit the B-cell and mature it and let it undergo class switching (IgG, IgA, IgE) Without CD40 second signal, the first pathway is the only remaining pathway, flooding it, producing high IgM. |
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In Hyper IgM-syndrome you would be susceptible to what?
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Low IgA, IgG, and IgE result in recurrent pyogenic infections (due to poor opsonization), especially at mucosal sites.
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What is a clinical presentation of Wiskott-Aldrich syndrome? What is it due to?
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Characterized by thrombocytopenia, eczema, and recurrent infections (defective humoral and cellular immunity). Due to mutation in the WASP-gene; X-linked.
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A 3 year old boy has a scalp rash. His mother had an episode of rash when she was young but doctor thought nothing about it. A rapidly increasing mass on the boy's neck has developed. What is going on?
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Wiskott-Aldrich syndrome. X-linked recessive. There is an associated increased risk for malignant lymphomas.
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What is a mnemonic to remember which immunoglobulins are elevated in Wiskott-Aldrich?
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wEAskott-aldrich (elevated IgA, elevated IgE)
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Deficiency in these proteins make patients susceptible to Neisseria.
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C5-C9 deficiencies—increased risk for Neisseria infection (N. gonorrhoeae and N. meningitidis)
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A woman has episodes of periorbital swelling and a "choking" sensation. What could be an underlying immunodeficiency?
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C1 esterase inhibitor deficiency. Continued C1 activation decreases C2 and C4 and increases their cleavage products, which have anaphylatoxic activity. C3 would be normal.
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This is the MC complement deficiency. What are some associations?
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C2; Association with septicemia (usually Streptococcus pneumoniae) and lupus-like syndrome in children.
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A patient has the following sign. He has a smaller than normal thymic shadow. He has had trouble with walking and maintaining a balanced gait for a long time. alpha-fetoprotein is high. What could be wrong?
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Ataxia-Telangiectasia. Mutation in DNA repair enzymes. AR. There is an increased risk for lymphoma and/or leukemia. IgA are often low.
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