Congenital Immunodeficiencies Flashcards

1
Q

What are the 3 SCID immunodeficiencies?

A

All Rats Amazing

(1) ADA
(2) RAG1/RAG2
(3) Artemis

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2
Q
(SCID)
ADA 
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B-, NK-
(2) IgM-, IgG-, IgA-
(3) Autosomal
(4) Severe opportunistic infections
(5) No live vaccines
(6) HSCT

  • susceptible to viral, bacterial, fungal infections at birth
  • leads to accumulation of metabolic byproducts (Deoxyadenosine) which is toxic to lymphocytes
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3
Q
(SCID)
RAG1/RAG2
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B-, NK+ (CD56)
(2) IgM-, IgG-, IgA-, high IgE
(3) Autosomal
(4) Severe opportunistic infections
(5) No live vaccines
(6) HSCT

  • impaired VDJ recombination which leads to defective expression of pre-TCR and pre-BCR
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4
Q
(SCID)
Artemis
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B-, NK+ (CD56)
(2) IgM-, IgG-, IgA-
(3) Autosomal
(4) Severe opportunistic infections
(5) No live vaccines
(6) HSCT

  • increased risk of developing lymphomas
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5
Q

What are the 7 selective B cell immunodeficiencies?

ALL HAVE T+ and NK+

A

Bad Cats Are Good At HuMping TooMuch

  • BTK agamma-globulinemia
  • Common variable (CVID)
  • IgA
  • IgG subclass
  • Agamma-globulinemia
  • Hyper-IgM syndrome
  • Transient hyper-IgM
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6
Q
(SELECTIVE B CELL)
BTK Agamma-Globulinemia
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B-, NK+
(2) IgM-, IgG-, IgA-
(3) X-linked
(4) Recurrent bacterial infections
(5) No live vaccines
(6) HSCT

  • mutation in tyrosine kinase – BTK
  • BTK gene found on X chromosome
  • caused by defect in rearrangement of IgG heavy chain genes
  • B cell maturation halted at Pre-B cell stage and doesn’t leave bone marrow
  • likely find normal or decreased Pre-B cells in bone marrow and IgM heavy chains in cytoplasm
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7
Q
(SELECTIVE B CELL)
Agamma-Globulinemia
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B-, NK+
(2) IgM-, IgG-, IgA-
(3) Autosomal
(4) Recurrent bacterial infections
(5) No live vaccines
(6) HSCT

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8
Q
(SELECTIVE B CELL)
Common Variable (CVID)
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B-, NK+
(2) low IgG, low IgA, SOMETIMES low IgM
(3) N/A
(4) Recurrent (extracellular) bacterial infections, autoimmune diseases, lymphomas
(5) No restrictions
(6) Depends on sxs

  • caused by mutations in either receptors for B cell growth factors (maturation/activation) or costimulators (T-B collab)
  • characterized by defect in Ab production
  • B cells fail to differentiate into plasma cells
  • not typically dx until 20-30 YO
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9
Q
(SELECTIVE B CELL)
IgA
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B+, NK+
(2) IgM+, IgG+, IgA-
(3) Autosomal but higher in male
(4) Mostly asymptomatic – higher risk of developing mucosal infections b/c IgA found in mucous membranes, dx based on hx of recurrent encapsulated bacterial infections
(5) No restrictions
(6) Depends on sxs

  • IgA produced in response to B cell secretion of IL-5 or TGF-β (NOT HAPPENING HERE)
  • B cells respond to lack of IgA by overproducing IgE which leads to increase in allergic rxns
  • pathogens causing infection in mucosal lining often look similar to self antigens which causes immune system to start attacking our own cells (molecular mimicry)
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10
Q
(SELECTIVE B CELL)
IgG Subclass
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B+, NK+
(2) IgM+, IgG+, IgA+, IgE+
(3) Autosomal
(4) Mostly asymptomatic
(5) No restrictions
(6) Depends on sxs

  • typically associated with poor responses in children to vaccines that contain polysaccharide Ags
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11
Q
(SELECTIVE B CELL)
Hyper-IgM Syndrome
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B+, NK+
(2) IgM+, IgG-, IgA-
(3) X-linked and autosomal
(4) Encapsulated opportunistic infections – esp bacterial infections
(5) POLIO not recommended
(6) HSCT is definitive treatment for this

  • believe X-linked version caused by defect in CD40L (males only), most common form
  • could be due to autosomal deficiency in CD40
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12
Q
(SELECTIVE B CELL)
Transient Hyper-IgM
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B+/-, NK+
(2) IgM+, IgG-, IgA-
(3) N/A
(4) Encapsulated opportunistic infections
(5) POLIO not recommended
(6) Depends on sxs

  • instead of producing IgG beginning at 6 months of age, these infants don’t produce IgG and IgA for up to 36 months
  • IgM normal or HIGH
  • typically normalize btwn 2-4 years of age
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13
Q

What are the 7 selective T cell immunodeficiencies?

A

(1) Common γ Chain
(2) IL-7R α Chain
(3) Jak3
(4) CD3
(5) MHC Class I (BLS I)
(6) MHC Class II (BLS II)
(7) DiGeorge Syndrome

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14
Q
(SELECTIVE T CELL)
Common γ Chain / Jak3
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B+, NK-
(2) IgM+, low IgG, low IgA
(3) Unknown – common deficiency is inherited as autosomal recessive
(4) Severe opportunistic infections
(5) No live vaccines
(6) HSCT

  • results from mutation in JAK3 (tyrosine kinase)
  • causes defect in IL-2R signaling which is key cytokine in proliferation of all T cells – can’t have proliferation of CD4 or CD8
  • causes defect in IL-15R signaling which is key cytokine in proliferation of NK cells
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15
Q
(SELECTIVE T CELL)
IL-7R α Chain
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B+, NK+
(2) IgM+, IgG & IgA & IgE are absent or VERY LOW
(3) Autosomal recessive
(4) Severe opportunistic infections
(5) No live vaccines
(6) HSCT

  • IL-7 normally functions in promoting proliferation of B and T cells, and survival of memory cells
  • Abs low or absent due to absent T cell co-stimulatory signaling
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16
Q
(SELECTIVE T CELL)
CD3
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B+, NK+
(2) IgM+, IgG-, IgA-
(3) Autosomal recessive
(4) Recurrent viral infections
(5) No live vaccines
(6) HSCT

  • mutations occur in delta, gamma, epsilon, or zeta chains
  • typically present in infancy with lymphoenia (decreased T cell numbers)
  • infants exhibit failure to thrive, opportunistic infections, and chronic diarrhea
17
Q
(SELECTIVE T CELL)
MHC Class I (BLS I)
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T+, B+, NK-
(2) IgM+, IgG+, IgA+
(3) Autosomal recessive
(4) Recurrent viral infections – due to absence of CD8+ cells
(5) No restrictions
(6) Depends on sxs

  • caused by mutation in TAP1 or TAP2
  • normal Ab production
  • NK cells exhibit low killing activity
18
Q
(SELECTIVE T CELL)
MHC Class II (BLS II)
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) CD4 lymphopenia
(2) IgM+, IgG-, IgA-
(3) Autosomal recessive
(4) Severe opportunistic infections – recurrent resp, GI and urinary tract infections; death in early childhood likely
(5) No live vaccines
(6) HSCT

  • professional APCs unable to activate CD4+ cells – leading to deficient production of TH cells
  • MHC class II genes are intact on chromosome 6
  • mutations present in genes that encode for transcription factors that regulate expression of MHC class II genes
19
Q
(SELECTIVE T CELL)
DiGeorge Syndrome
(1) Immune phenotype
(2) Ab panel
(3) Inheritance
(4) Infections
(5) Vaccination
(6) Treatment
A

(1) T-, B+, NK+
(2) IgM+, low IgG, low IgA
(3) Autosomal DOMINANT
(4) Recurrent viral infections – mostly respiratory infections
(5) No restrictions
(6) Depends on sxs

  • often have deficiency in mature T cells
  • results from microdeletion in chromosome 22
  • classic triad of sxs: cardiac anomalies, hypocalcemia, hypoplastic thymus
  • if have this disorder then unlikely to reject skin graft b/c T cell response is what mediates rejection of graft
20
Q

What are the 3 defects of activation and function of T cells? (defects observed after T cell maturation is complete)

A
  • IPEX
  • ALPS
  • Wiskott-Aldrich Syndrome (WAS)
21
Q

IPEX

A
  • X-linked

- self-reactive T cells are not inhibited due to mutation in the FOXP3 gene that results in absent CD4+ CD25+ Treg cells

22
Q

ALPS

A
  • defects in either Fas (CD95) or FasL (CD95L) gene
  • results in decreased/no formation of death-inducing signaling complex and resistance and resistance of T cells to apoptosis
  • sxs: extremely large lymph nodes b/c T cells not dying
23
Q

Wiskott-Aldrich Syndrome (WAS)

A
  • X-linked disorder
  • T-, B+, NK-
  • characterized by thrombocytopenia (few platelets, platelets smaller in size than normal), eczema, cellular and humoral immunodeficiency, autoimmune disease, malignancy
  • caused by mutations in WASP (protein, produced by all hematopoietic cells in body)
  • present w/ recurrent bacterial infections with encapsulated bacteria, viral infections, and opportunistic infections
  • develop combined cellular and humoral immunodeficiency:
    (1) low IgM, normal IgG, elevated IgA and IgE
    (2) T cell lymphopenia
    (3) low NK cytotoxicity
24
Q

What are the 5 phagocytic cell deficiencies?

A

(1) Leukocyte Adhesion Deficiency
(2) Chronic Granulomatous Disease (CGD)
(3) Glucose 6P Dehydrogenase Deficiency
(4) Myeloperoxidase Deficiency
(5) Chediak-Higashi Syndrome

25
Q
(PHAGOCYTIC)
Leukocyte Adhesion Deficiency
(1) Cellular Abnormality
(2) Immune Defect
(3) Associated Infections and Other Diseases
A

(1) Defective CD18 cell (cell adhesion molecule)
(2) Defective migration of phagocytes into infected tissues
(3) Widespread infections with encapsulated infections

  • neutrophils show low expression of LFA-1 (CD11/CD18)
  • neutrophil count in blood is twice the normal level b/c cells can’t get into tissues
26
Q
(PHAGOCYTIC)
Chronic Granulomatous Disease (CGD)
(1) Cellular Abnormality
(2) Immune Defect
(3) Associated Infections and Other Diseases
A

(1) Defective NADPH oxidase, phagocytes cannot produce O2-
(2) Impaired killing of phagocytosed bacteria
(3) Chronic bacterial and fungal infections; granulomas

  • more common in males
27
Q
(PHAGOCYTIC)
Glucose 6P Dehydrogenase Deficiency 
(1) Cellular Abnormality
(2) Immune Defect
(3) Associated Infections and Other Diseases
A

(1) Deficiency in Glucose 6P Dehydrogenase, defective respiratory burst
(2) Impaired killing of phagocytosed bacteria
(3) Chronic bacterial and fungal infections; anemia induced by certain agents; granulomas

  • XR hereditary disease
  • associated w/ anemia b/c enzyme needed for metabolism of RBCs
28
Q
(PHAGOCYTIC)
Myeloperoxidase Deficiency 
(1) Cellular Abnormality
(2) Immune Defect
(3) Associated Infections and Other Diseases
A

(1) Deficiency of Myeloperoxidaseimn neutrophil granules and macrophage lysosomes, and impaired production of toxic oxygen species
(2) Impaired killing of phagocytosed bacteria
(3) Chronic bacterial and fungal infections

  • AR inherited disorder
  • infections almost exclusively seen in patients who develop DM
  • MPO catalyzes conversion of H2O2 to HOCL (bleach); enzyme that gives green puss color
29
Q
(PHAGOCYTIC)
Chediak-Higashi Syndrome
(1) Cellular Abnormality
(2) Immune Defect
(3) Associated Infections and Other Diseases
A

(1) Defect in vesicle fusion
(2) Impaired phagocytosis due to inability of endosomes to to fuse with lysosomes
(3) Recurrent and persistent bacterial infections; prone to granulomas caused by strep; effects on many organs

  • AR disorder
  • Neutrophils with abnormal giant granules
  • Granules DO NOT contain Cathepsin G and Elastase
  • associated with aberrant degranulation and chemotaxis
  • dx based on finding of azurophilic GIANT cytoplasmic granules in neutrophils and eosinophils, partial albinism, and aberrant NK cell activity