Immunodeficiency Flashcards

1
Q

Which class of immunodeficiency has absence of lymphoid tissue and profound lymphopenia?

A

Severe combined immunodeficiency disorder (SCID)

Examples:
Adenosine deaminase deficiency

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2
Q

What is X-linked (Bruton) agammaglobulinemia (XLA)? When and what bacteria do infants get?

A

BTK defect –> prevents pre-B cells from maturing and exiting bone marrow –> Reduced Ig levels
Sinopulmonary infections with encapsulated bacteria after 6 months old (when maternal antibodies decrease) - antibody opsonization needed for phagocytosis
Small/absent lymphoid tissue

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3
Q

What viral infections can X-linked agammaglobulinemia predispose to?

A

Chronic enteroviral infection (e.g. meningoencephalitis) (Coxsackie, Echovirus, Polio - due to lack of antibodies to neutralize disease

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4
Q

What is treatment for X-linked (Bruton) agammaglobulinemia?

A

Immunoglobulin replacement therapy
Prophylactic antibiotics if failed

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5
Q

What bacteria susceptibility due to chronic granulomatous disease with reduced phagocytic activity?

A

Impaired oxidative burst (defective NADPH oxidase) leads to recurrent infections caused by catalase+ bacteria (S aureus, Serratia, Burkholderia, Nocardia) and fungi (eg Aspergillus)

NORMAL T and B cell levels

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6
Q

Chronic granulomatous disease granuloma locations

A

Digestive tract
GU tract

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7
Q

Chronic granulomatous disease prophylaxis

A

Bactrim, itraconazole

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8
Q

Severe combined immunodeficiency

A

Defective IL-7 driven T cell development in thymus; leading to low B cells

T: Viral, fungal, opportunistic

B: Sinopulmonary and GI bacterial

Chronic diarrhea, failure to thrive

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9
Q

What is a named variant of SCID?

A

Adenosine deaminase deficiency - deficient formation of mature B and T cells

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10
Q

How is SCID diagnosed?

A

Absence of T receptor excision circles in dried blood (newborn screening)

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11
Q

Common variable immunodeficiency

A

Hypogammaglobulinemia, so less severe than Bruton
Due to impaired differentiation of B cells into plasma cells
Presents at later age with normal T and B cell levels

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12
Q

CVID is associated with what noninfectious conditions?

A

Atopic (eg asthma, eczema) or autoimmune (eg RA) conditions

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13
Q

Wiskott-Aldrich

A

X-linked recessive - important for regulation of actin cytoskeleton remodeling needed for cellular migration and immune synapse formation

Bleeding from microthrombocytopenia
Recurrent infections
Eczema

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14
Q

Wiskott-Aldrich treatment

A

Hematopoietic stem cell transplant

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15
Q

Hyper-IgM

A

High IgM, low IgA and IgG
X-linked recessive CD40 ligand (on T cells) mutation, which impairs binding to CD40 on B cells (impairs class switching, leading to sinopulmonary) and APCs (leading to viral, opportunistic)
Lymphocytosis and neutropenia during infection
Impaired growth from high energy expenditure and poor intake during illness
Treat with antibiotic prophylaxis and IVIG

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16
Q

Hyper-IgE

A

Defective Th17 cells –> defective neutrophil proliferation/chemotaxis to site of infection
Cold abscesses, afebrile, well-appearing
Often S aureus, Candida
Recurrent sinopulmonary
Chronic, severe atopic dermatitis in first few weeks of life
Eosinophilia

Autosomal dominant

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17
Q

Selective IgA deficiency

A

May be asymptomatic, but could also:
Hx of recurrent sinopulmonary and Gi infections
Concomitant atopic and autoimmune disorders

18
Q

Selective IgA deficiency should beware what?

A

Blood transfusion anaphylactic reaction - use epinephrine

19
Q

Defective opsonization is due to what?

A

Low IgG or complement (C3), predisposing to encapsulated bacteria and sinopulmonary infections

20
Q

Leukocyte adhesion deficiency

A

Due to reduced CD18 component of integrins on neutrophil surface

Poor neutrophil chemotaxis, leading to recurrent skin and mucosal infections without purulence
Delayed wound healing (e.g. delayed separation of umbilical cord >3 wks)

21
Q

Absence of purulence with repeated skin and mucosal infections suggests…

A

Leukocyte adhesion deficiency

22
Q

Diagnosis of chronic granulomatous disease

A

Dihydrorhodamine 123 (flow test that is green if normal)

23
Q

What immunodeficiency may cause inflammatory bowel disease in a toddler?

A

Chronic granulomatous disease –> impaired ROS production –> severe, recurrent infections

CGD –> impaired ROS production –> impaired degradation of inflammatory cytokines –> inflammation and diffuse granuloma formation in GI/GU tracts

Pigment-laden histocytes are seen, representing lipofuscin accumulation due to impaired lipolytic activity

24
Q

Early complement deficiency is susceptible to…
Late is susceptible to…

A

Early:
Recurrent sinopulmonary bacteria (C3 deficiency)
Childhood SLE

Late:
Recurrent encapsulated bacteria, particularly Neisseria (C5-C8 deficiency)

25
Q

Hyper-IgE syndrome

A

Impaired neutrophil chemotaxis –> cold (nontender, nonfluctuant) abscesses

26
Q

Recurrent Neisseria infections suggests what immunodeficiency?

A

Complement deficiency

27
Q

What immunodeficiency is associated with ocular injection?

A

Ataxia-telangiectasia - immune defects can be variable (can affect both humoral and cellular) but at least recurrent sinopulmonary infections
Due to defective DNA repair

28
Q

What infections does IFN-g deficiency predispose to?

A

Disseminated mycobacterial disease (IFN-g mediates intracellular killing of mycobacteria by macrophages)

29
Q

What is cyclic neutropenia?

A

Recurrent episodes of reduced peripheral neutrophils, fever, sore throat, and LAD every 3 weeks

30
Q

What is transient hypogammaglobulinemia of infancy?

A

Prolonged (age >6 mo) IgG nadir - asymptomatic or recurrent respiratory infections in infancy
May also atopy (eg eczema, food allergies)
Low IgG (+/- decreased IgA or IgM) but normal antibody response to vaccines

31
Q

Chediak-Higashi syndrome

A

Lysosomal trafficking disorder - giant granules will accumulate within neutrophils

Recurrent infections and neutropenia
Oculocutaneous albinism
Neurologic abnormalities

32
Q

Oculocutaneous albinism suggests…

A

Chediak-Higashi syndrome

33
Q

When are infants considered high-risk towards highly allergenic food?

A

Known/suspected IgE-mediated food allergy
Severe, refractory eczema

Refer to allergy testing (IgE levels, skin testing) and consider in-office feeding

34
Q

Why does hyper-IgM come with decreased levels of all Ig except IgM?

A

CD40 ligand deficiency on T cells

35
Q

Which immunodeficiency has recurrent Neiserria, meningicoccal, or gonococcal infections?

A

Terminal complement deficiency (C5-C9)

Mke sure to give meningococcal vaccine and antibiotics as needed

36
Q

Increased IgE and IgA but decreased IgM

A

Wiskott-Aldrich

37
Q

Bleeding, eczema, recurrent otitis media

A

Wiskott-Aldrich

38
Q

Giant granules in neutrophils

A

Chediak-Higashi - defect in neutrophil chemotaxis and microtubule polymerization

39
Q

Recurrent S aureus infections and abscesses

A

Job syndrome (Hyper-IgE)

40
Q

Partial oculocutaneous albinism

A

Chediak-Higashi - overwhelming S pyogenes, S aureus, and Pneumococcus infections