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Flashcards in Clinical Immunology Deck (60)
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1
Q

newborn screening for SCID

A

T-cell receptor excision circles (TREC)

  • >99% sens for classic and hypomorphic forms of SCID
  • doesn’t screen for PIDs where normal amt of T cell receptors are created
2
Q

CGD Management

A
  • follow ESR and radiographs
  • ppx antibiotics/antifungals: Bactrim, itra
  • ppx IFN-g 3x/wk
  • BMT or gene therapy
3
Q

How to approach suspected T-cell defect:

A
  1. obtain lymphocyte subsets and ALC
  2. if ALC low in young age –> think SCID!!
  3. if ALC normal –> eval T-cell fxn (mitogens, Ags)
4
Q

Dx of IFNgR deficiencye

A

genetics

flow cytometry

5
Q

erythroderma

desquamation

organomegaly

eosinophilia

A

think Omenn syndrome

  • can be d/t hypomorphic SCID mutations (e.g. reduced CD3+ T cell, <30% T-cell function)
  • most often a/w RAG1/RAG2 defects
6
Q

Complement Defects where AI disease is more common (SLE, DLE, etc)

A

C1-4 defects

7
Q

What consider with disseminated NTM infections (or even with disseminated histo or cocci)

A

IFNgR deficiencies (AR more severe)

AR = complete defect, childhood, more severeAD = partial defect, later in life

8
Q

most commonly implicated pathogens in complement deficiencies

A

encapsulated bacteria

  • S pneumo
  • H flu (type B)
  • N meningitidis
9
Q

how to approach suspected phagocytic defect:

A
  1. CBC, ANC
  2. if low ANC - consider cyclic neutropenia, AI neutropenia, referral to heme for BMBx
  3. if normal ANC - think CGD (obtain DHR burst testing), LAD (CD11/CD18 flow)
10
Q

Dx and Tx CVID

A
  • decreased IgG (total + subclass 1,3 or 2,4), IgA, IgM
  • decreased response to new/recall immunization

Rx: treat infections, Ig replacement

11
Q

mechanism of CGD

A

NADPH oxidase defects –> inability to produce superoxide anions

*inflamed tissue around uncleared pathogen creates granulomas

12
Q

PID w/ increased predisposition to invasive candidiasis

A

CARD9 deficiency - familial candidiasis

13
Q

with high IgE, think:

A
  • Hyper IgE syndrome (Job’s)
  • DOCK18 deficiency
14
Q

Infections commonly seen in Chediak-Higashi syndrome

A

recurrent cutaneous and sinopulmonary infections

  • GNR, staph, strep
  • (no fungi)
15
Q

Antibody-dependent bacterial lysis complement pathway

Defic: recurrent bacteremia and meningitis

A

Classical Complement Pathway (C1-9)

16
Q

Defects to consider when:

  • FTT
  • skin rash
  • diarrhea
  • OI at any age
A

T cell defects

17
Q

very common PID in adults - presents with recurrent respiratory and GI infections

A

think CVID

  • low levels serum Igs, with decreased specific Ab response
  • be sure to exclude other causes of hypoIg (much more common than CVID) - rx-induced, infection, malignancy
18
Q

Defects to consider when:

respiratory/GI sx after 1st few mos of lifeenterovirus meningoencephalitisrecurrent sinusitis, pnas, bronchiectasis

A

think B-cell defects (usually present after maternal Abs wane)

19
Q

Complement Defect

recurrent neisseria BSI/meningitis

(typically 17yo, mild CNS)

A

C5-9 defects

20
Q

thrombocytopenia (Decreased MPV)

eczema

recurrent infectionsoften with autoimmunity or malignancy

A

Wiskott-Aldrich syndrome

d/t mutations in WAS protein (WASP)

21
Q

hyper IgE (97% >2000)

eosinophilia (93% >2SD)

A

think HIE

no correlation b/w IgE and eos)

22
Q

essential cells for killing of fungi

A

phagocytes (neuts, monos, macrophages, eos, basos)

23
Q
  • teen/adult onset
  • recurrent HPV infections
  • disseminated NTM (esp mediastinal M kansasii)
  • pancytopenia: w/ profound monocytopenia - low B, low NK)
  • CT - subpleural blebs
A

think GATA2 deficiency

Dx: genetics, hypocellular marrow

24
Q

Deficiency responsible for leukocyte adhesion deficiency 1

A

CD18 → loss of integrins

25
Q

Primary immunodeficiencies a/w increased predisposition to EBV

A

**Chronic EBV viremia, EBV-assoc lymphoproliferative d/o

  • ITK def
  • MAGT1 def
  • STK4 def
  • CD27 def
  • Coronin-1A def
26
Q

lab definition of SCID

A
  • T-cell count <300 +
  • absence of T-cell response to mitogens (<10% compared w/ control)
27
Q

Diagnostic tests for complement defects

A

CH50 - Classical

AH50 - Alternative

28
Q

Eczema

allergies

asthma

High IgE

HPV, HSV, molluscum

Candida, crypto, histo

pseudomonas

A

think DOCK8 deficiency

(more GN and more viral infections than with Job’s)

recalcitrant, severe HPV

also think with NTM

**does not have other features of Job’s: retained teeth, path fx, pneumatoceles

29
Q

Defects to consider when:

Cellulitis w/o pus

granulomas

IBD

liver abscesses

prolonged attachment of umbilical cord

A

phagocytic defects

30
Q

SCID

megaloblastic anemia

atypical HUS (sometimes)

A

think methylenetetrahydrofolate dehdyrogenase def (MTHFD1)

31
Q

Most common Ig deficiency

A

IgA

not often detected, not a/w disease (though can be a/w other deficiencies like CVID and other Ig subclass deficiencies)

32
Q

Confirm dx of IFNgR1 deficiency

A

show high IFNgR1 on cell surfaces (truncated, so can’t be taken off)

33
Q

When to consider hyper IgE (HIE) Job’s syndrome

A
  • recurrent sinopulmonary infections (SA, SP, H flu)
  • post-infections pulm cyst formation
  • recurrent SA skin abscesses
  • characteristics: facies, eczema, scoliosis, path fx
  • very elevated IgE (>2000), eosinophilia
  • Mutation of STAT3
34
Q

most common presentation of CD40 ligand deficiency

A

PJP pneumonia

other common: cryptosporidium, cryptococcus

GI disease (diarrhea, liver dysfunction)

high risk of lymphomas, liver cancers

35
Q

Infections in chronic granulomatous disease

A

Catalase-positive bacteria

Fungi

–> Tissue granuloma formation

36
Q

common infections seen with CVID

A
  • recurrent sinu-pulm infections
  • chronic enteric infections (giardia, campy, salmonella, shigella)
  • severe echoviral meningitis/encephalitis, myositis
37
Q

screening labs for phagocytes

A

DHR - for superoxide

FACS - CD18, CD11a-c, IFNgR1, IL-12RB1

38
Q

associated with antibody-negative pulmonary alveolar proteinosis (PAP)

A

GATA2 deficiency

39
Q

PIDs with increased predisposition to mycobacterial infections

A
  • IL12 deficiency
  • IL23 deficiency
  • IFNgR deficiency
40
Q
  • Teeth loss, gingivitis
  • Impaired wound healing
  • Dystrophic “cigarette paper” scars
  • Delayed umbilical stump separation
  • Often no purulence seen
  • (bx w/o neutrophils at site of infection)
A

think LAD1

41
Q

neutropenia, splenomegaly + often RA

A

Felty syndrome

  • GOF in STAT3
  • large granular lymphocytosis
42
Q

How to approach suspected B-cell defects

A
  1. obtain lymphocyte subsets and ALC
  2. if low ALC - ?combined ID - target T-cell eval
  3. if normal ALC - obtain B-cell number, quant Igs, Ab response to vaccines
  • absent B cell early age - think XLA
  • abnormal number/function - XLA, hyperIgM syndromes, CVID
  • adult onset - CVID
43
Q

Infections common with LAD1

A
  • recurrent necrotizing infections: skin, perineum, lung, gut
  • GPC, enteric GNR (NOT fungal)

**will have baseline leukocytosis (sometimes as high as 100 with infection)

44
Q

high IgM

low/absent IgG, IgA, IgE

A

CD40 ligand deficiency

  • CD40 ligand expressed on activated CD4 T cells (CD40 on B-cells)
  • –> CD4+-deficient patients (CD4 cells non-functioning)
  • interaction required for B cell survival, growth, differentiation (IgM not able to class-switch)
45
Q
  • Eczema
  • Abnormal facies (increased nasal width)
  • recurrent boils
  • recurrent PNA –> pulmonary cysts
  • scoliosis
  • delayed dental deciduation
  • coronary artery aneurysms
  • pathologic fractures
A

think HIE (Job’s) syndrome

*pulmonary cysts will form after infection, even with adequate tx – often get 2ary infected

46
Q

giant granules in neutrophil

A

Chediak-Higashi syndrome

(mutations in Lyst - cause giant primary and fused secondary granules within the cytoplasm of neutrophil)

47
Q

Diagnosis of CGD

A

Preferred: PMN DHR (dihydrorhodamine 123 oxidation)

PMN nitroblue tetrazolium reduction (NBT)

– results from failure to produce superoxide and its metabolites

48
Q

most common severe PID

A

SCID (1/60k live births)

results from many different genetic defects

49
Q

recurrent sino-pulmonary bacterial infections

A

CVID

50
Q

Complement Pathway with Ab INdependent bacterial lysis

Defic: severe disease

A

Alternative Pathway (Factors I, H, properdin, C3)

–> protects before Abs enter the picture

51
Q

infections a/w CGD

A

nearly pathognomic = infections with rare catalase+ orgs:

  • granulibacter bethesdensis
  • chromobacterium
  • francisella

burkholderia

nocardia

aspergillus (look for in non-neutropenic pt)

52
Q

PIDs with increased predisposition to chronic mucocutaneous candidiasis

A
  • IL-17 deficiency
  • autoimmune polyendocrine candidiasis ectodermal dystrophy (APECED) - CMC, Addison, hypoparathyroid, metaphyseal dysplasia
53
Q

PIDs with increased predisposition to HPV

A
  • epidermodysplasia verruciformis - disseminated flat, wart-like papules
  • CXCR4 def - myelokathexis (retention of neuts in bone marrow) + hypoIgs + warts
  • DOCK8 def - hyperIgE + eos, severe viral skin infections
  • GATA2 def - not as much as DOCK8. monocytopenia, NK def, pulmonary alveolar proteinosis
54
Q

Criteria for HLH

A

(5 of 8 required) *prolonged, excessive activation of AP and cytotoxic cells d/t inability to clear inciting pathogen –> cytokine storming

  • fever
  • SM
  • cytopenias (Hgb<9, plt <100, ANC <1K)
  • TG >265
  • fibrinogen <150 (low)
  • ferritin >500
  • IL-2 receptor (>2400) - marker of T-cell activation
  • low/absent NK activity
  • hemophagocytosis on path
55
Q
  • disseminated NTM later in life
  • female
  • East Asian (born there)
A

Anti-IFNg autoantibody syndrome

Dx w/ autoAb detection

56
Q

common clinical manifestations of Chediak-Higashi

A
  • Infections (Bacterial, not fungal)
  • Mild neutropenia (d/t intramedullary destruction)
  • Partial oculocutaneous albinism
  • Mental retardation
  • Neuropathy
  • Lymphoma/HLH-like phase
57
Q

PIDs with increased predisposition to cryptosporidium

A

IL-21 receptor def - chronic cholangitis and cirrhosis d/t prolonged cryptosporidium infection

58
Q

Only part of immune system to control aspergillosis

A
  • phagocytes (neuts, monos, macrophages, eos, basophils)
  • In otherwise normal host = aspergillosis means phagocytic defect
59
Q

dx/tx Chediak-Higashi

A

Dx: giant blue granules w/in neut

Mutation in CHS1 (encodes Lyst)

Rx: bacterial ppx (Bactrim), tx infections, ?BMT

60
Q

Defects to consider with:

  • strep, neisseria infections
  • rheumatoid disorders
A

complement deficiencies