Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immunology & Inflammation > Immunodeficiency > Flashcards

Immunodeficiency Flashcards

1
Q

What are the three major phagocyte dysfunction disorders? What conditions and infections are these patients more susceptible to?

A
  • leukocyte adhesion deficiency (LAD)
  • Chediak-Higashi syndrome
  • chronic granulomatous disease (CGD)
  • increased susceptibility to extracellular (most) bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is leukocyte adhesion deficiency (LAD)? How do patients with LAD present?

A
  • an autosomal recessive defect in phagocytes’ LFA-1 integrin (CD18 subunit), preventing adhesion to the endothelial wall during inflammation/immune responses
  • (remember integrin binds to ICAMs for adhesion)
  • patients present with a delayed separation of the umbilical cord (neutrophils normally adhere to umbilical tissue to destroy the necrotic tissue), failure to form pus, and an increased number of circulating neutrophils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is there an increased number of circulating neutrophils in leukocyte adhesion deficiency (LAD)?

A
  • normally, about 50% of the body’s neutrophils are attached to the blood vessels of the lungs, where they wait to be recruited (known as the marginated neutrophil pool)
  • in LAD, they are unable to attach to these vessels and are therefore already freely floating in the blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is Chediak-Higashi Syndrome? How do patients present?

A
  • an autosomal recessive protein trafficking defect due to a microtubule deficiency (mutation in the lysosomal trafficking regulator gene LYST)
  • results in impaired phagolysosome formation (phagosome and lysosome fail to fuse), so phagocytosis is severely impaired; many other issues result as well due to impaired trafficking
  • patients present with recurrent pyrogenic infection with Staph and Strep (bacteria can’t be killed), partial albinism (light skin and silver hair; melanin isn’t distributed well), peripheral neuropathy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is chronic granulomatous disease (CGD)? Which organisms are patients highly susceptible to?

A
  • X-linked recessive defect in NADPH oxidase results in the inability to generate an oxidative burst to destroy the organism in the phagolysosome
  • increased susceptibility to catalase positive organisms: (PLACESS) Pseudomonas, Listeria, Aspergillus, Candida, E. coli, Staph aureus, Serratia
  • results in infectious granulomas (hence the name, CGD)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In chronic granulomatous disease, why does the inability to generate an oxidative burst only occur when dealing with catalase positive organisms?

A
  • even in CGD, neutrophils can still usually generate the oxidative burst because most bacteria produce H2O2 (hydrogen peroxide), which can be used to create free radicals (with these organisms, we don’t need to use NADPH oxidase and SOD to create H2O2)
  • catalse positive bacteria, however, have catalase, which prevents the formation of bacterial H2O2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What investigation is used to test for chronic granulomatous disease?

A
  • (CGD is a lack of NADPH oxidase)
  • the nitroblue tetrazolium test (NBT test)
  • in normal patients who can convert O2 into supraoxide (meaning they have NADPH oxidase), the dye turns blue
  • in patients with CGD, the dye does not turn blue (a negative test)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Familial Mediterranean Fever?

A
  • a mutation resulting in massive IL-1 production, resulting in large and uncontrolled inflammatory responses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the four main T-cell disorders? What conditions and infections are these patients more susceptible to?

A
  • DiGeorge syndrome (AKA thymic aplasia)
  • IL-12 receptor deficiency
  • hyper-IgE syndrome (AKA Job syndrome)
  • chronic mucocutaneous candidiasis
  • patients are more prone to developing sepsis, viral infections, and Candidiasis (this is because these are intracellular organisms)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is DiGeorge syndrome?

A
  • (this is a T-cell disorder, resulting in susceptibility to intracellular organisms such as viruses and fungi)
  • DiGeorge syndrome is due to a 22q11 deletion resulting in thymic and parathyroid aplasia (hence it is simply AKA thymic aplasia) (the 3rd and 4th pharyngeal pouches fail to develop)
  • patients also present with low levels of PTH and hypocalcemia (tetany) because of the lack of parathyroids, and an absent thymic shadow on CXR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is IL-12 receptor deficiency? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a T-cell disorder, resulting in susceptibility to intracellular organisms such as viruses and fungi)
  • an autosomal recessive disorder resulting in a decreased Th1 cell response (IL-12 is released by macrophages and is needed to differentiate helper T-cells into Th1 cells)
  • patients also present with lowered IFN-gamma (because IFN-gamma is normally secreted by Th1 cells)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is hyper-IgE syndrome (AKA Job syndrome)? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a T-cell disorder, resulting in susceptibility to intracellular organisms such as viruses and fungi)
  • a STAT3 mutation results in deficiency of Th17 cells, resulting in impaired recruitment of neutrophils
  • patients also present with FATED: (coarse) Facies, (cold; not inflamed) Abscesses, retention of primary Teeth, elevated IgE, and Dermatologic problems (such as eczema)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is chronic mucocutaneous candidiasis? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a T-cell disorder, resulting in susceptibility to intracellular organisms such as viruses and fungi)
  • this condition is a result of certain T-cell dysfunction
  • patients present with chronic noninvasive infections of the skin and mucous membranes with Candida albicans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the three main B-cell disorders? What conditions and infections are these patients more susceptible to?

A
  • X-linked (Bruton) agammaglobulinemia
  • IgA deficiency
  • common variable immunodeficiency (CVID)
  • increased susceptibility to encapsulated bacteria (SHiNE SKiS: Strep pneumoniae, Hib, Neisseria meningitidis, E. coli, Salmonella, Klebsiella, Strep agalactiae (group B Strep)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is X-linked (Bruton) agammaglobulinemia? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a B-cell disorder, resulting in susceptibility to encapsulated organisms)
  • X-linked recessive mutation in Bruton’s tyrosine kinase (BTK) gene results in loss of B-cell maturation into plasma cells and therefore decreased humoral immunity (all types of Abs are decreased)
  • patients usually present with increased infections after 6 months (this is when maternal IgG starts to wear off), they also have very scanty (or absent) lymph nodes and tonsils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is IgA deficiency? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a B-cell disorder, resulting in susceptibility to encapsulated organisms)
  • the most common primary immunodeficiency
  • unknown cause; results in an increased risk of mucosal infections (because IgA is normally found on mucosal surfaces)
  • patients have normal Ig levels except for IgA; majority of patients are asymptomatic
17
Q

What is CVID? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a B-cell disorder, resulting in susceptibility to encapsulated organisms)
  • common variable immunodeficiency; many causes, poorly understood etiology
  • CVID is a defect in B-cell differentiation, resulting in decreased number of plasma cells and immunoglobulins (hypogammaglobulinemia); it often doesn’t present until early-mid adulthood (20s-40s)
18
Q

What are the four major disorders that affect both T- and B-cells?

A
  • SCID (severe combined immunodeficiency)
  • ataxia-telangiectasia
  • hyper-IgM syndrome
  • Wiskott-Aldrich syndrome
19
Q

What is SCID? In addition to the increased susceptibility to certain infections, how else do patients present? How do we treat it?

A
  • (this is a T- and B-cell disorder)
  • severe combined immunodeficiency
  • several causes resulting in defects in both cell-mediated and humoral immunity due to inability of stem cells to develop/mature into T- and B-cells; most common is X-linked mutation in IL-2R cytokine receptor gene
  • problem fighting all organisms and infections
  • patients present with failure to thrive (FTT), absent thymic shadow (because of atrophy due to lack of activity), absent germinal centers upon lymph node biopsy, and no T-cells
  • treat with a bone marrow transplant
20
Q

What is the major etiology of SCID? What are the other two causes?

A
  • major etiology is defective cytokine receptors (mainly IL-2 receptor)
  • others causes: adenosine deficiency (results in toxic product build-up in lymphocytes and their cell death), MHC class II deficiency
21
Q

What is ataxia-telangiectasia? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a T- and B-cell disorder)
  • a defective ATM (ataxia-telangiectasia mutated) gene results in arrest of the cell cycle (ATM is normally activated by breaks in the DNA during replication)
  • patients also present with a classic triad of cerebellar defects (ataxia), spider angiomas (telangiectasia), and Ig deficiency (IgA, IgG, and IgE)
22
Q

What is hyper-IgM syndrome? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a T- and B-cell disorder)
  • a defect in the CD40L on helper T-cells or in the CD40 receptor on B-cells results in an inability for B-cells to undergo class switching
  • patients present with severe pyogenic infections early in life, excess levels of IgM and lowered levels of IgG, IgA, and IgE
23
Q

What is Wiskott-Aldrich syndrome? In addition to the increased susceptibility to certain infections, how else do patients present?

A
  • (this is a T- and B-cell disorder)
  • X-linked mutation in the WASp (WIskott-Aldrich syndrome protein) gene, results in the inability for T-cells to reorganize the cytoskeleton (required for phagocytosis and podosome formation)
  • patients present with classic triad of thrombocytopenia (decreased platelets), eczema, and recurrent infections
24
Q

What organisms are patients with a complement deficiency most susceptible to?

A
  • main risk is with Neisseria species

Immunology & Inflammation (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions