immunodeficiences

Question 1

X-linked agammaglobulinemia

Answer 1

absence of mature B cells –> little serum antibody of any isotype

Question 2

common variable immunodeficiency

Answer 2

deficiency of all antibodies due to inability of mature B cells to differentiate into plasma cells

Question 3

selective IgA deficiency

Answer 3

intrinsic B cell defect –> no IgA
normally IgM compensates for lack of IgA at mucosal barriers
produce anti-IgA antibodies –> transfusion reactions
most common

Question 4

hyper IgM syndrome

Answer 4

overabundance of IgM, lack of other isotypes

due to inherited deficiency of CD40L –> no isotype switching

Question 5

DiGeorge syndrome

Answer 5

deficiency of T cells due to hypolasia or agenesis of thymus
poor cell-mediated immunity
CXR shows absence of thymic shadow
normal antibody levels

Question 6

SCID

Answer 6

failure of B and T cells to develop from bone marrow stem cells
no humoral or cell-mediate immunity
immunization with live attenuated is fatal
may be due to:
deficiency of ADA
deficiency of PNP
deficiency of RAG1/RAG2 –> VDJ rearrangement failure

Question 7

CGD

Answer 7

defect in NADPH oxidase in neutrophils –> incapable of producing superoxide anion
IFN gamma can prompt neutrophils
recurrent bacterial infections

Question 8

myeloperoxidase deficiency

Answer 8

absent myeloperoxidase enzyme
can’t produce HOCl, which is antibacterial/antifungal
decreased ability to ward of fungal infections (Candida)

Question 9

Chediak-Higashi syndrome

Answer 9

neutrophils contain large granules due to fusing of lysosomes –> reduced ability to kill microbes
metallic silver hair

Question 10

LAD-1

Answer 10

defect in beta chain of LFA-1 and Mac-1 adhesion molecules –> neutrophils incapable of extravasation

Question 11

neutropenia

Answer 11

mutation in neutrophil elastase enzyme –> buildup of toxic intracellular protein
severe congenital and cyclic

Question 12

Wiskott-Aldrich syndrome

Answer 12

X-linked
lymphocytes respond poorly to antigen, can't traffic to inflammation site
TRIAD OF SYMPTOMS:
eczema
immunodeficiency
lack of platelets

Question 13

ataxia-telangiectasia

Answer 13

ataxia, vascular lesions, radiation sensitivity, tumors
defect in ATM –> problems responding to DNA damage
reduced T cells
defective T helper cells
decreased IgA, IgE, and IgG2