Nelson- Immunodeficiency syndromes Flashcards Preview

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Flashcards in Nelson- Immunodeficiency syndromes Deck (45)
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What is the difference between primary and secondary immunodeficiencies? and what populations do they effect?

Primary--almost all geneticall determines (congenital) affect those 6 mos - 2 yrs

Secondary- d/t complications of cancer, infection, malnutrition, immunosuppression, radiation or chemo


What do primary immunodeficiencies affect?

T or B cell functions in adaptive immunity (75% of cases)

Defense mechanisms in innate immunity


How are primary immunodeficiencies detected?

multiple recurrent infections


What are B cell disorders?

IgA def
Hyper-IgM syndrome


Key features: brutons

X-linked recessive
Mutated tyrosine kinase (Btk)
Failure of pre-b cells to become MATURE B cells


Clinical features of brutons?

• Typical presentation: sinopulmonary (SP) infections (pharyngitis, otitis media, bronchitis, and pneumonia) to Haemophilus
• Susceptible to certain GI viruses (enterovirus)
• Often have persistent Giardia infection (no IgA in GI)


Why does Brutons often present at 6 mos?

Maternal Ab protects from birth to 6 mos than Ig decreases


What do you see in the peripheral blood of someone w/ brutons?

Decrease/absent B cells and gammaglobulins
No plasma cells


What is the treatment for brutons?

prophylactic Ig therapy


Key features: common variable immunodeficiency?

Defect in B-cell maturation to plasma cells

Adult disorder--both sexes affected equally


Common clinical sxs of CVI?

Sx similar to agammaglobulinemia:
SP infections (90-100%),
GI infections,
autoimmune diseases


What is seen in the blood of someone w/ CVI?

decreased gammaglobluin production


What are the two forms of CVI and how is it diagnosed?

sporadic and inherited
dx of exclusion


Key features: IgA def

Failure of IgA B cells to mature into plasma cells

Increases susceptibility to SP infections and diarrhea

Familial or acquired


Clinical features of IgA def?

• Decreased serum and secretory IgA levels
• Decreased IgA → weaken mucosal defenses → increased SP infxns and diarrhea (Giardia)
• Particularly prone to infxns if IgG2 and IgG4 deficient


Key features: hyper-IgM syndrome?

• Defect in Ig class switching (Unable to make IgG, IgA and IgE but can make IgM)
• ~70% have X-linked recessive mutation in gene encoding CD40L (T cell cannot activate B cells)
• Others have defect in activation-induced deaminase enzyme (AR inheritance)


What is seen in labs of someone w/ hyper IgM syndrome?

normal to elevated levels of IgM but no IgA, IgE, and very low IgG; peripheral blood shows normal # of T and B lymphocytes


What illnesses does someone w/ hyper-IgM syndrome have?

• Recurrent pyogenic infections
• If CD40L mutation → pneumonia (Pneumocystis jiroveci)
• Increased risk: IgM induced cytopenias (autoimmune hemolytic anemias, thrombocytopenias, neutropenia)


What type of disorder is DiGeorge syndrome?

T cell disorder


Key features: DiGeorge syndrome?

• Failure of 3rd and 4th pharyngeal pouches to develop
• Thymus and parathyroid glands fail to develop → deficiency in cell-mediated immunity
• D/t delection of gene on chrom 22q11 (~90% pts)
• Susceptible to fungal, viral, pneumocystis jirveci infections


What clinical features are associated w/ DiGeorge syndrome?

• Hypoparathyroidism (tetany)
• Absent thymic shadow on radiograph
• Danger of GVH rxn
• Congenital defects of heart and great vessels, facial abnormalities


What is seen in the peripheral blood of some one w/ DiGeorge syndrome?

• Low levels of T lymphocytes in peripheral blood
• T cell areas in spleen and lymph nodes depleted


What diseases are combined B and T cell disorders?

Wiskott Aldrich syndrome
Chediak HIgashi syndrome


What are the two defects that lead to SCID?

X-linked mutation in gene encoding γ-chain subunit of cytokine receptor (50-60%) → T cell development impaired → B cell # decreases b/c no T helpers

Autosomal recessive adenosine deaminase (ADA) deficiency (15%) → accumulation of deoxyadenosine (toxic to B and T cells)


What are the clinical features of SCID?

• Profound defects in both humoral and cell mediated immunity

• Extremely susceptible to recurrent, severe infections


What is seen in infants w/ SCID?

Infants: thrush, extensive diaper rash, failure to thrive


What is the tx for combined B and T cell disorders?

bone marrow transplant


What is the defect associated w/ Wiskott aldrich syndrome? Inheritance?

Mutation in Wiskott-Aldrich syndrome protein (WASP) → variable loss of cell-mediated immunity

Progressive deletion of B and T cells

X-linked recessive disorder


What is the sx triad for wiskott aldrich syndrome?

eczema, thrombocytopenia, SP infections

Increased risk for hodgkin B cell lymphoma


What is seen in the blood of someone with wiskott aldrich syndrome?

Decreased IgM
normal IgG
increased IgA and IgE