Acquired and Innate Immune Deficiencies Flashcards

1
Q

Discuss the warning signs of primary immunodeficiency.

A
  • 4+ ear infections/yr
  • 2+ sinus infections/yr
  • 2+ pneumonias/yr
  • failure to thrive
  • recurrent deep skin abscesses
  • persistent fungal (mouth/skin)
  • IV antibiotics/2+ mon. w/o effect
  • 2+ infections w/septicemia
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2
Q

B cell Immune Deficiency: common infections

A

• recurrent sinopulmonary (decreased IgA)
infections or sepsis
• usually encapsulated organisms
• chronic meningoencephalitis

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3
Q

B cell Immune Deficiency: lab tests

A

Ig levels
specific Ig titers
flow cytometry (B cell #)

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4
Q

B cell Immune Deficiency: examples

A

X-linked agammaglobulinemia
common variable immunodeficiency
selective IgA deficiency

Note: antibody deficiencies = 65% of innate immunologic disorders

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5
Q

T cell Immune Deficiency: common infections

A
  • opportunistic infections
  • recurrent + severe common infections
  • failure to thrive, diarrhea
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6
Q

T cell Immune Deficiency: lab tests

A

CBC w/ differential
flow cytometry
T cell functional study
Ig levels

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7
Q

T cell Immune Deficiency: examples

A

DiGeorge syndrome
Wiskott Aldrich syndrome
SCID (B + T cell)

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8
Q

Phagocytic immune deficiency: common infections

A

• soft tissue abscesses or lymphadenitis
• infections w/catalase (+) organisms [S.
aureus, Serratia, Aspergillus]
• poor wound healing

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9
Q

Phagocytic immune deficiency: lab tests

A

CBC w/differential
PMN oxidative burst assay
flow cytometry

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10
Q

Phagocytic immune deficiency: examples

A

chronic granulomatous disease
leukocyte adhesion defect

Note: phagocytic deficiencies = 10% of primary immunodeficiencies

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11
Q

Complement immune deficiency: common infections

A
  • recurrent disseminated Neisseria
  • autoimmune disease
  • bacterial sepsis
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12
Q

Complement immune deficiency: lab tests

A

CH50 measures

classical complement cascade

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13
Q

Complement immune deficiency: examples

A

terminal complement deficiency

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14
Q

Innate defects in immune system: common infections

A
  • septicemia

* poor inflammatory response

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15
Q

Innate defects in immune system: lab tests

A

TLR signaling

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16
Q

Innate defects in immune system: examples

A

IRAK4 mutation
NEMO mutation
MyD88 mutation

17
Q

Severe Combined Immunodeficiency (SCID)

A

18+ genes

  • early detection + TX [newborn screening]
  • ≠ normal T cell #s (look for TRECs = biomarker for T cell development)
  • fatal within 1st year if no immune reconstitution (bone marrow transplant, gene therapy, PEG-ADA, thymic transplant)
18
Q

DiGeorge Syndrome

A

22q11.2: microdeletion (1:3k-6k)
- classic triad: hypocalcemia, ♥ defect, thymic dysfunction
o Tetralogy of Fallot, decreased lymphocytes [lymphs made = good, do well]
o can do thymus transplant if thymus absent/incomplete

19
Q

Common Variable Immunodeficiency (CVID)

A

~Relatively common (1:65k)

• Inherited primary immunodeficiency = bimodal presentation: 10 years and 30 years.

A defect in B cell differentiation and/or function

  • Dx: marked decrease in IgG and at IgM or IgA; and has:
    1) onset greater than 2 years old
    2) absence of isohemagglutinins and/or poor response to vaccines (functional defect)
    3) exclude defined causes of hypogammaglobulinemia

• Increased incidence of lymphoid malignancy, autoimmune disease, and atopy.
• Incidence of autoimmune disease in CVID patients = 25%
TX: IVIG (long-term), antibiotics, suppress immune system

20
Q

Wiskott Aldrich syndrome (WAS)

A

Spectrum, X-linked recessive

  • present w/ recurrent infections, decreased platelets, eczema => increased risk of autoimmunity + malignancy
  • WAS protein expressed in blood cells = functions to modulate actin cytoskeleton
  • actin cytoskeleton has role in immune function

o ID + TX: genotype-phenotype relationships + clinical scoring system

TX:  IVIG, replace immune system w/ bone marrow transplant, gene therapy
21
Q

X-linked lymphoproliferative disorder (XLP)

A
  • mutation in SH2D1A gene (encodes SLAM-associated protein)
    = involved in NK cell development + CD8+ responses in EBV infection

Typical presentation:
after EBV infection = fulminant liver failure
-due to severe immune dysregulation
–> fatal mononucleosis, hemophagocytic lymphohistiocytosis (HLH), lymphoma, aplastic anemia

Tx: bone marrow transplant, B cell depletion therapy early in EBV infection course

22
Q

Chronic Granulomatous Disease (CGD)

A

X-linked + autosomal recessive

  • disruption of NADPH oxidase complex function
    o inability of PMNs to kill w/ ROS
    o esp. catalase (+): S. aureus, Klebsiella, Aspergillus, Burkholeria, Serratia
  • Increased WBCs, Increased Ig, (-) HIV

TX: antibiotics prophylaxis, IFN-γ prophylaxis, corticosteroids, bone marrow transplant, gene therapy

23
Q

Define secondary or acquired immunodeficiency and distinguish from primary immunodeficiency

A

Primary immunodeficiencies are caused by defects which originate in the immune system itself.

Secondary immunodeficiencies are due to insufficiency of a supporting component of the immune system or an external or “secondary” depleting factor.

24
Q

Explain that a large variety of conditions have a negative impact on immune function

A
Endocrine/physiologic
Gastrointestinal
Hematologic/Oncologic
Infectious
Rheumatologic
Renal
Iatrogenic/environmental/toxic
25
Q

Describe several examples of infections with worse outcomes in pregnant women

A
  • Hepatitis A and B
  • Influenza
  • Herpes viruses
  • Chlamydia/GC
  • Listeria
  • Campylobacter
  • Tuberculosis
  • Malaria
26
Q

Explain the specific risk of infection with the use of TNF inhibitors.

A

Patients at risk for Granulomatous infections

Ex: mycobacterial infection, endemic fungal infections (histoplasmosis)

27
Q

MOA of immune deficiency: aging

A

“Immune senescence”

Associated changes:

  • progressive decrease in size and function of thymus
  • decrease in suppressor cell function –> increase in auto reactivity
  • changes in lymphocyte development and function = higher risk of latent virus reactivation (ex: VZV to cause shingles)
28
Q

MOA of immune deficiency: malnutrition

A

-impaired cellular and humoral immunity

-MOS relates to:
Global metabolic disturbances
low levels of leptin
deficient intake of protein, fat, vitamins, minerals
deficiencies in zinc, iron, folate, pyridoxine, Vitamin A

29
Q

MOA of immune deficiency: protein losing conditions

A

Ex: nephrotic syndrome or protein loosing enteropathy; IBD, Celiac’s, burns, peritoneal dialysis

-can result in hypo-gammaglobulinemia

30
Q

MOA of immune deficiency: pregnancy

A

Modulated immune condition:

  • Progesterone = inhibits lymphocyte proliferation in vitro
  • Uromodulin = pregnancy specific serum factor that inhibits B cell activity
  • Depressed T cell response
31
Q

MOA of immune deficiency: diabetes

A
  • impair function of cells involved in cellular and/or humoral immunity
  • –MOST prominent: neutrophil dysfunction

-Type I: more immune dysregulation (autoimmune disease)
-Hyperglycemia = makes neutrophil function worse
-Other factors:
co-existing vascular disease = poor circulation/neuropathy = ulceration = poor wound healing = infection = difficulty clearing infection = complications
-CV compromise

32
Q

MOA of immune deficiency: malignancy

A
  • impaired cell-mediated and humoral responses
  • bone marrow involvement = interferes with growth and development lymphocytes
  • tumors may produce substances that interfere with lymphocyte development or function
B cell deficiencies have been noted in:
• Multiple myeloma
• Waldenstrom's macroglobulinemia
• Chronic lymphocytic leukemia
• Well differentiated lymphomas

T cell deficiencies have been noted in:
• Hodgkin’s disease
• Advanced solid tumors

33
Q

MOA of immune deficiency: rheumatologic disease

A
  • immune dysregulation = autoimmunity
  • increased susceptibility to infection
Includes:
Lupus
RA
Granulomatosis with polyangiitis (GPA, formerly Wegener’s granulomatosis) 
IBD
34
Q

Summarize some important infections associated with the secondary immune deficiency of cirrhosis

A

MOA:

  • Shunting of portal blood so decreased ability of Kupffer cells to clear organisms
  • hypocomplementemia = reduces serum opsonic activity
  • reduced hepatic metabolism of endogenous gluccocorticoids = immune suppressive

Most common complications:

  • sepsis
  • bacterial peritonitis

Unusual infections associated with cirrhosis:
• Cryptococcal infection
• Candidal infection
• Infection with Vibrio vulnificus

35
Q

Summarize some important infections associated with the secondary immune deficiency of diabetes

A

Common infections of increased frequency and severity:
• Pneumonias ( viral, strep pneumo)
• UTI ( including pyelonephritis)
• Cellulitis
• Diabetic foot infections
• Infections with candida (superficial) Vaginitis, thrush

Some unusual infectious complications of diabetes include:
• Infections with candida (deep)
• Rhinopulmonary zygomycosis (mucormycosis)
• Malignant otitis externa due to P. aeruginosa.