Immunodeficiencies Flashcards

1
Q

B cell disorders

A
Bruton Agammglobulinemia (X-linked)
Selective IgA deficiency
Common Variable Immunodeficiency
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2
Q

Bruton agammaglobulinemia- defect

A

X-linked

Defect in BTK (tyrosine kinase): prevent B cell maturation

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3
Q

Bruton agamma- S&S

A

Recurrent bacterial (and enteroviral) infections (after 6 mo- when mom’s IgG is depleted)

Absent, scanty lymph nodes

Decreased level of all Igs

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4
Q

Selective IgA deficiency- defect

A

Unknown, but most common primary immunodef

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5
Q

Selective IgA def- S&S

5 A’s

A

Recurrent mucosal infections (GI- Giardia)

Majority Asymptomatic, but may affect Airways, Anaphylaxis (with blood transfusion), Autoimmune dz, Atopy (allergy- e.g. eczema, rhinitis, asthma)

Decreased level of IgA

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6
Q

Combined Variable Immunodeficiency- defect

A

Lots of causes; defect in B-cell differentiation

Causes decreased Igs and plasma cells

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7
Q

CVID- S&S

A

Can be acquired; often see in 20s-30s

Increased risk of autoimmune diseases (despite the decrease in Igs), lymphoma, bronchiectasis, and sinopulmonary infections

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8
Q

T cell disorders

A

Thymic aplasia (diGeorge)
IL-12 receptor deficiency
Hyper-IgE (Job) Syndrome
Chronic mucocutaneous candidiasis

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9
Q

Thymic aplasia (diGeorge)

A

Failure of “Thyrd” and 4th pharyngeal pouches to develop (causes lack of thymus and parathyroids) –> absent thymic shadow (also seen in SCID)

Underlying chr 22q11 deletion (detected by FISH)

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10
Q

Thymic aplasia- S&S

A

Recurrent viral/fungal infections
Decreased T-cells, PTH, and Ca2+

Other S&S: tetany (hypocalcemia), conotruncal abnormalities (tetrallogy of Fallot, truncus arteriosus),

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11
Q

IL-12 receptor deficiency- defect

A

Decreased Th1 response (also have decreased IFN gamma- normally produced by Th1 cells to activate macrophages)
Autosomal recessive

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12
Q

IL12-receptor deficiency- S&S

A

Disseminated mycobacterial and fungal infections (may present after BCG vaccine)

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13
Q

Hyper-IgE (Job) Syndrome- defect

A

Deficiency of Th17 (due to mutation in STAT3) –> impairs neutrophil/ macrophage recruitment to infection site (because can’t produce proper cytokines like IFN-gamma)

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14
Q

Hyper-IgE (Job) Syndrome- S&S (FATED)

A
Any kid (girl/boy) w/: FATED
Facies (coarse)
Abscesses (staphylococcal)
Teeth (retained)
E- increased IgE
Dermatologic probs (Eczema)
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15
Q

Chronic mucocutaneous candidiasis-defect and S&S

A

T-cell dysfunction (many causes) –> absent T cell response to Candida antigens

Non-invasive Candida infection (in mucosa and skin)

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16
Q

B cell and T cell disorders

A

SCID (severe combined immunodeficiency)
Ataxia-Telangiectasia
Hyper-IgM
Wiskott-Aldrich

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17
Q

SCID- defect

A

Many causes, but two main mutations:
IL-2R gamma chain deficiency (X-linked)
Adenosine Deaminase deficiency (AR)

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18
Q

SCID- S&S

A
Recurrent infections (bacterial, viral, fungal, and protazoal)
Failure to thrive, chronic diarrhea, thrush
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19
Q

SCID- dx

A

Absent thymic shadow (also seen in diGeorge)
Absent germinal centers (lymph node biopsy)
Absent T cells (flow cytometry)
Decreased T cell receptor excision circles (indicate maturation of T cells)

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20
Q

SCID- tx

A

Bone marrow transplant (no concerns about potential graft rejection by host- because there are no B/T cells)

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21
Q

Ataxia-telangiectasia- deficit

A

Mutation in ATM gene –> failure to repair dsDNA breaks –> causes cell-cycle arrest

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22
Q

Ataxia-telangiectasia- S&S

A

Triad: Ataxia (cerebellar Atrophy), spider Angiomas, IgA (and IgG and IgE) deficiency (recurrent mucosal infections)

Hypersensitivity to ionizing radiation

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23
Q

Ataxia-telangiectasia- lab findings

A

Increase AFP
Decreased IgA, IgG, and IgE (impaired isotope switching)
Lymphopenia

24
Q

Hyper-IgM syndrome- deficitis

A
Defective CD40L ligand on T cells (impairs isotype class switching)
X-linked recessive (as opposed to hyper IgE --> which is AD)
25
Q

Hyper IgM- S&S

A

Severe pyogenic infections in early life; opportunistic infections (Pneumocystis, Cryptosporidium, CMV)

Normal or increased IgM
Very low IgA, IgE, and IgG (lower than Ig levels in Ataxia-Telangiectasia)

26
Q

Wiskott-Aldrich syndrome- deficits

A

Mutation in WAS gene –> T cells unable to reorganize actin cytoskeleton

X-linked recessive

27
Q

Wiskott-Aldrich- S&S

A

Male with (WA)TER:
Thrombocytopenia
Eczema
Recurrent infections (pyogenic- pus)

Increased risk of malignancy and autoimmune disease

Distinguish from hyper-IgE due to male in Wiskott-Aldrich (XR) vs. females can also get hyper-IgE (AD); also thrombocytopenia only seen in Wiskott-Aldrich

28
Q

Wiskott-Aldrich- Findings

A

Decreased/normal IgG and IgM
Increased IgE and IgA
Fewer and smaller platelets

29
Q

Phagocyte dysfunction

A

Leukocyte adhesion deficiency
Chediak-Higashi
Chronic granulomatous disease

30
Q

Leukocyte adhesion (LAD) deficiency (type 1)- deficit

A

Due to deficiency in LFA-1 integrins (CD18) on phagocytes; impaired migration and chemotaxis
AR

31
Q

LAD type 1- S&S

A

Recurrent bacterial skin and mucosal infections
Absent pus formation (requires neutrophils to consolidate)
Impaired wound healing and delayed separation of umbilical cord

32
Q

LAD- lab findings

A

Increased neutrophils, but absent at infection sites (can detect via flow cytometry to find CD 18)

33
Q

Chediak-Higashi syndrome- deficits

A

Defect in lysosomal trafficking regulator gene (LYST)

Causes microtubule dysfunction in phagosome-lysosome fusion (AR) –> lysosome emptying defect

34
Q

Chediak-Higashi syndrome- S&S

A

ALBINO + recurrent infections + neuro probs

Recurrent pyogenic infections by staphylococci and streptococci
Partial ALBINISM
Peripheral neuropathy
Progressive neurodegeneration
Infiltrative lymphohistiocytosis
May present with oral ulcers and gingivitis

35
Q

Chediak-Higashi syndrome- lab findings

A
Giant granules (in granulocytes and platelets)
Pancytopenia
Mild coagulation defects
36
Q

CGD- defects

A

Mutation in NADPH oxidase (XR) –> prevents the formation of superoxides (specifically oxygen radical)

Impaired respiratory burst
Increase risk of infection with catalase + organisms because with other bacteria, neutrophils can use bacterial peroxides to generate ROS (thereby bypassing the first step of converting oxygen to an oxygen radical), but for bacteria that have catalase, that peroxide is converted to water, so host phagocytes (e.g. neutrophils) cannot generate the superoxide (HClO- dot) to kill bacteria.

37
Q

CGD- S&S

A

Recurrent infection with catalase + organisms: N- PLACES

Nocardia
Pseudomonas A.
Listeria
Aspergillus
Candida
E. coli
Serratia, staphylococci
B. cepacia
H. pylori
38
Q

CGD- diagnosis

A

Abnormal dihydrorhodamine (low fluorescence) or negativenitroblue tetrazolium test –> indicates that ROS are not being formed

39
Q

Bacterial infections in T-cell deficiency

A

Sepsis

40
Q

Bacterial infections in B-cell deficiency

A

Please SHINE my SKiS (encapsulated)

Pseudomonas A
Strep pneumo
H. influenzae
Neisseria meningitis
E. coli
Salmonella
Klebsiella
Strep
41
Q

Bacterial infections in granulocyte deficiency

A
Staphylococcus
B cepacia
P aeruginosa
Serratia
Nocardia
42
Q

Bacterial infections in decreased complement

A

Encapsulated species (for early complement deficiencies)

Neisseria (with MAC/ late complement deficiencies)

43
Q

Viral infections in T cell deficiencies

A

CMV, EBV, JCV, VZV, chronic respiratory/GI viruses

44
Q

Viral infections in B cell deficiencies

A

Enteroviral encephalitis, poliovirus (live vaccine is contraindicated)

45
Q

Fungi/parasites in T cell deficiencies

A

Candida (local), PCP

46
Q

Fungi/parasites in B cell deficiencies

A

GI giardiasis (no IgA)

47
Q

Fungi/parasites in granulocyte deficiencies

A

Candida

Aspergillus

48
Q

General trend: B vs. T cell deficiencies

A

B cell deficiencies: Produce more recurrent infections

T cell deficiencies: Produce more fungal and viral infections

49
Q

Autograft

A

from self (most effective; e.g. for Hodgkin Lymphoma)

50
Q

Syngeneic (isograft)

A

from identical twin/ clone

51
Q

Allograft

A

from non-identical individual of the same species

52
Q

Xenograft

A

from different species

53
Q

Hyperracute transplant rejection

A

Type II HS; activate complement (within minutes)

Preformed antibodies reject donor tissue/ cells

Thrombosis of graft vessels –> ischemia/ necrosis

Requires graft removal

54
Q

Acute transplant rejection

A

Type II and Type IV (CD8 T cells) HS reactions: (within weeks to months)

Gradual accumulation of antibodies and/ or cytotoxic T-cells against donor tissue/ MHCs

Vasculitis with DENSE INTERSTITIAL LYMPHOCYTE infiltrate

Tx: prevent/ reverse with immunosuppressants

55
Q

Chronic

A

Type II and Type IV (with CD 4 T cells): within months to years

Gradual accumulation of helper T cells against donor MHCs

Recipient T cells react and secrete cytokines

Histology: SCANT INFLAMMATORY CELLS AND INTERSITIAL FIBROSIS, proliferation of vascular smooth muscle; dominated by arteriosclerosis (e.g vanishing bile duct syndrome)

56
Q

Graft vs. host disease

A

“Graft rejects host”

Graft T cells invade the host tissue and cause several organ dysfunction via Type IV HS reaction

Usually occurs with BMTs and liver transplants; causes maculopapular rash, jaundice, diarrhea, and HSM

Potentially beneficial in BMT for leukemia (where donor cells kill the leukemia/ tumor cells)