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Immunology Flashcards

1
Q

Part of lymph node cortex…
Contains germinal center
B-cell localization and proliferation

A

FOLLICLE

Secondary follicles have pale germinal center surrounded by mantle and are active

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2
Q

Part of lymph node containing…
Cords of closely packed Lymphocytes/Plasma Cells
Sinuses containing Reticular Cells/Macrophages
Communication with efferent lymphatics

A

MEDULLA

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3
Q

Part of lymph node between Follicles and Medulla…
Houses T cells
Contains high endothelial venules from which T/B cells can enter from the blood

A

PARACORTEX

Enlarges with viral infection

Not well developed in patients with DiGeorge syndrome

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4
Q

Drainage of trachea and esophagus.

A

Mediastinal lymph nodes.

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5
Q

Drainage of upper limb, breast, and skin above umbilicus.

A

Axillary lymph nodes.

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6
Q

Drainage of liver, stomach, spleen, pancreas, and upper duodenum.

A

Celiac lymph nodes.

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7
Q

Drainage of lower duodenum, jejunum, ileum, and colon to splenic flexure.

A

Superior mesenteric lymph nodes.

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8
Q

Drainage of colon from splenic flexure to upper rectum.

A

Inferior mesenteric lymph nodes.

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9
Q

Drainage of lower rectum to anal canal above pectinate line, bladder, vagina, cervix, and prostate.

A

Internal iliac lymph nodes.

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10
Q

Drainage of testes, ovaries, kidneys, and uterus.

A

Para-aortic lymph nodes.

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11
Q

Drainage of anal canal below pectinate line, skin below umbilicus, scrotum, and vulva.

A

Superficial inguinal nodes.

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12
Q

Drainage system of right side of body above diaphragm.

A

Right lymphatic duct.

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13
Q

Drainage system emptying into left subclavian and internal jugular veins.

A

THORACIC DUCT

Drains everything not drained by the right lymphatic duct

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14
Q

Location of T cells in the spleen.

A

Periarteriolar lymphatic sheath (PALS) in white pulp surrounding central arteriole.

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15
Q

Location of B cells in the spleen.

A

Follicles in white pulp between PALS and marginal zone.

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16
Q

Location in spleen where APCs capture blood-borne antigens for presentation.

A

MARGINAL ZONE

Between red pulp and white pulp

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17
Q

Mechanism of encapsulated bacteremia due to splenic dysfunction.

A

Decreased IgM
Decreased complement activation
Decreased C3b opsonization
Increased susceptibility to encapsulated organisms

("Please SHiNE my SKiS")
Pseudomonas
S. pneumo
HIB
Neisseria
E. coli
Salmonella
Klebsiella
gbS
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18
Q

Howell-Jolly bodies
Target cells
Thrombocytosis
Lymphocytosis

A

Asplenia

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19
Q

Embryologic origin of thymus.

A

Third pharyngeal arch

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20
Q

Hypoplastic thymus.

A

DiGeorge syndrome

SCID

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21
Q

Enlarged thymus.

A

Myasthenia gravis.

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22
Q

Mechanism of pathogen recognition by the innate immune system.

A

Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns (PAMPs) such as LPS, flagellin, and nucleic acids.

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23
Q

MHCI gene loci.

A

HLA-A/B/C

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24
Q

MHCII gene loci.

A

HLA-DP/DQ/DR

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25
Q

Cells expressing MHCI

A

All nucleated cells - Except RBCs

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26
Q

Cells expressing MHCII

A

APCs

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27
Q

Presents endogenously synthesized antigens (viral, cytosolic proteins) to CD8+ cytotoxic T cells.

A

MHCI

Antigens loaded in RER after delivery via TAP - associated with B2-microglobulin

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28
Q

Presents exogenously synthesized antigens (bacterial proteins) to CD4+ helper T cells.

A

MHCII

Antigen loaded following release of invariant chain in acidified endosome.

Note - Made of a/b polypeptide chains

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29
Q 
Hemochromatosis
Addison's
Myasthenia Gravis
Celiac
MS
Hay fever
Goodpasture
SLE
Graves
T1DM
Hashimoto's
Rheumatoid Arthritis
Pernicious Anemia
Steroid responsive nephrotic syndrome
A 
HLA-A3
HLA-B8/DR3/DR4
HLA-B8
HLA-DQ2/8
HLA-DR2
HLA-DR2
HLA-DR2
HLA-DR2/3
HLA-DR3
HLA-DR3/4
HLA-DR3/5
HLA-DR4
HLA-DR5
HLA-DR7
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30
Q

Diseases (“PAIR”) associated with HLA-B27 - also known as the seronegative arthropathies.

A

Psoriatic arthritis
Ankylosing spondylitis
IBD-associated arthritis
Reactive arthritis (Reiter syndrome)

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31
Q

Activated when exposed to non-specific activation signal, or decreased MHCI expression on target cell (e.g. malignancy, viral)

Express CD16 (Fc of IgG), CD56 (unique)

Secretes IFN-y

A

NATURAL KILLER CELL

Induced by IL-2, IL-12, IFN

Note - Do not require thymic maturation and so found in athymic patients

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32
Q

Mechanism of NK cell action.

A

Perforins allow entry of granzymes and induce apoptosis in virally infected cells and tumor cells (lack MHCI)

Also kills via antibody-dependent cell-mediated cytotoxicity - CD16 binds Fc region of bound Ig activating NK cell

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33
Q

Mechanism of B-cell maturation

A

Precursors in bone marrow (VDJ recombination)
Migration to lymph nodes/peripheral tissues
Antigen exposure
Some become temporary Plasma Cells secreting IgM
Most travel to germinal centers for proliferation
Class switching/Somatic hypermutation

Note - Majority of opsonizing antibodies produced in spleen

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34
Q

Sites of T cell maturation.

A

Precursor in bone marrow
CD4/8+ in thymic cortex
CD4+ or CD8+ in thymic medulla
Cytotoxic or Helper (TH1, TH2, TH17) in lymph node

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35
Q

Mechanism of positive selection (thymic cortex).

A

Only T cells expressing TCRs capable of binding self-MHC survive.

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36
Q

Mechanism of negative selection (thymic medulla).

A

T cells expressing TCRs with high affinity for self antigens undergo apoptosis - allows for self-tolerance.

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37
Q

Inability to express tissue-restricted self-antigens in the thymus due to deficient AIRE.

A

Autoimmune polyendocrine syndrome 1

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38
Q 
Activates...
Macrophages
Cytotoxic T cells
NK cells
MHC expression by all cells

Secretes IFN-y

A

TH1 CELL

Induced by IL-12 (macrophages), IFN-y (self)
Inhibited by IL-4, IL-10 (TH2 cell, Treg)

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39
Q

Recruits eosinophils for parasite defense and promotes IgE/A production by B cells

Secretes IL-4, IL-5, IL-10, and IL-13

A

TH2 CELL

Induced by IL-4 (self)
Inhibited by IFN-y (TH1 cell)

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40
Q

Macrophage-lymphocyte interaction mechanism.

A

Macrophages/APCs release IL-12 which induces TH1 cells

TH1 cells in turn secrete IFN-y to stimulate macrophages - also inhibits TH2 cells, induced NK cells, and increases MHC expression

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41
Q

Mechanism of cytotoxic (CD8) T cells.

A

Release cytotoxic granules containing perforin and granzyme to induce apoptosis in virally infected, tumor, and donor graft cells.

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42
Q

Express CD4, CD25, and FOXP3

Produce IL-10, TGF-b (anti-inflammatory)

A

REGULATORY T CELLS

Maintain immune tolerance by suppressing CD4/8 T cell effector function

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43
Q

Mechanism of T cell activation (2 signals).

A

Dendritic cell migrates to draining lymph node

Antigen presented via MHC and TCR (signal 1 - activation)

Interaction of B7 (CD80/86) and CD28 (signal 2 - proliferation)

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44
Q

Mechanism of B cell activation (2 signals).

A

B-cell receptor-mediated endocytosis allows presentation of antigen via MHCII

Activated Th cell binds MHCII via TCR (signal 1)

CD40L on Th cell binds CD40 on B cell (signal 2)

Th cell secretes cytokines

B cell activates and undergoes class switching, affinity maturation, and Ig production

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45
Q

Mechanism of antibody diversity (antigen independent).

A

Random recombination of VJ (light-chain) or V(D)J (heavy-chain) genes

Random addition of nucleotides to DNA during recombination by terminal deoxynucleotidyl transferase (TdT)

Random combination of heavy chains with light chains

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46
Q

Mechanism of antibody specificity (antigen dependent).

A

Somatic hypermutation (variable region) and clonal proliferation leading to affinity maturation

Isotype/class switching (constant region)

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47
Q

Express IgM and IgD.

A

Naive B cells

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48
Q

CD responsible for mediating isotype/class switching.

A

CD40 (+cytokines)

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49
Q 
Monomer
Fixes complement
Opsonization (with C3b)
Neutralizes bacterial toxins and viruses
Cross placenta (infant passive immunity)
A

IgG

Most abundant serotype in plasma

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50
Q

Monomer in circulation
Dimer (J chain) when secreted
Does not fix complement
Produced in GI tract (Peyer’s patches; prevents Giardia)
Released into tears, saliva, mucous, breast milk
Prevents attachment of bacteria and viruses to mucous membranes

A

IgA

Most produced antibody but low serum concentrations

Crosses epithelial cell by transcytosis, and picks up secretory component from epithelial cells which protects Fc portion from luminal proteases

51
Q

Monomer as antigen receptor on B cell
Pentamer (J chain) when secreted
Fixes complement
Does not cross placenta

A

IgM

52
Q

Binds mast cells and basophils, then crosslinks when exposed to allergen to allow for release of inflammatory mediators (e.g. histamine)

Mediates immunity to worms by activating eosinophils

A

IgE

Lowest serum concentration

53
Q

Antigens lacking a peptide component (LPS)
Cannot be presented by MHC to T cells
Only IgM is produced

A

THYMUS-INDEPENDENT ANTIGENS

Protein conjugate helps initiate T-cell dependent stimulation of B lymphocytes - Results in memory cell response and thus longer duration of immunity (e.g. LPS, Polysaccharide-Conjugate vaccines)

Note - Humoral immunity is weak < 2 mo of age and so this is particularly important in newborns

54
Q

Antigens containing a protein component
Direct contact of B cells with Th cells
Class switching and immunologic memory occur

A

THYMUS-DEPENDENT ANTIGENS

E.g. Diphtheria vaccine

Note - Also provides mucosal immunity (herd immunity)

55
Q

Induced by IL-6 and produced in the liver.

A

Acute phase reactants

56
Q

Positive (upregulated) acute phase reactants.

A

CRP - opsonin (complement fixation, phagocytosis)
Ferritin - binds and sequesters iron
Fibrinogen - endothelial repair (ESR)
Serum amyloid A - leads to amyloidosis
Hepcidin - degrades ferroportin (decreased Fe absorption and release from macrophages)

57
Q

Negative (downregulated) acute phase reactants.

A

Albumin - reduced to conserve AA for positive reactants

Transferrin - Internalized by macrophages to sequester Fe

58
Q

Classic (antigen-antibody) and Lectin (microbial surface) complement cascade.

A 
C1 binds near hinge of IgM or IgG
Forms C2b and C4b
C3 convertase (C4b2b)
Forms C3b
C5 convertase
Forms C5b
With C6-C9 forms MAC - lysis and cytotoxicity (Gram-)
59
Q

Alternative (spontaneous and microbial surface) complement cascade.

A

C3 forms C3b
C3 convertase (C3bBb)
Forms C3b

60
Q

Function of C3a, C4a, C5a formed by complement cascade.

A

Anaphylaxis

Note - C5a also responsible for neutrophil chemotaxis

61
Q

Inhibitors of complement cascade on self cells (e.g. RBCs).

A

DAF (CD55) - prevents formation of C3 convertase

C1 esterase inhibitor

62
Q 
Episodes of...
Non-pitting edema
Respiratory obstruction
Abdominal pain
No pruritus or urticaria
A

HEREDITARY ANGIOEDEMA

Autosomal dominant C1 esterase inhibitor deficiency leads to increased conversion of Kallikrein to Bradykinin and activation of classical complement cascade - angioedema

Do not give ACEi

63
Q

Increases risk of severe, recurrent pyogenic sinus and respiratory tract infections

Increases susceptibility to type III hypersensitivity

A

C3 DEFICIENCY

64
Q

Complement deficiency increases susceptibility to recurrent Neisseria bacteremia.

A

C5-C9 DEFICIENCIES

65
Q

Causes complement mediated lysis of RBCs and paroxysmal nocturnal hemoglobinuria.

A

DAF DEFICIENCY

GPI-anchored enzyme

66
Q

Function of macrophage secreted ILs…

IL-1

IL-6

IL-8

IL-12

TNF-a

A

IL-1 (OAF) = Adhesion molecules, Chemokine secretion

IL-6 = APR

IL-8 = Chemotactic

IL-12 = Th1, NK

TNF-a = Septic shock, Cachexia (wasting due to underlying systemic disease), systemic inflammatory response

67
Q

Function of T cell secreted ILs…

IL-2

IL-3

A

IL-2 = Induces all T cells, NK cells, B cells, macrophages. If present for lengthy period can promote FAS mediated apoptosis

IL-3 = Like GM-CSF (stimulates stem cell production of granulocytes and monocytes)

68
Q

Function of TH2 secreted ILs…

IL-4

IL-5

IL-10

A

IL-4 = Induces Th2 cells, B cells, switching to IgE/G

IL-5 = Induces Eosinophils, B cells, switching to IgA

IL-10 = Inhibits Th1, APCs, MHCII (with TGF-B)

69
Q

Respiratory (oxidative) burst pathway in phagocytes (neutrophils, monocytes).

A

O2 + NADPH to Superoxide (NADPH oxidase)
Superoxide to H2O2 (Superoxide dismutase)
H2O2 + Cl to Hypochlorite (Myeloperoxidase)

Note - MPO blue-green heme containing pigment gives sputum its color

H2O2 reduced (Glutathione peroxidase)
Glutathione replenished (Glutathione reductase+NADPH)
NADPH from HMP shunt replenished (G6PD)

Note - Superoxide dismutase is technically an antioxidant as its product (H2O2) is eliminated by Glutathione Peroxidase and Catalase

70
Q

Mechanism of catalase+ infections in patients with CGD (NADPH oxidase deficiency).

A

Phagocytes can utilize H2O2 from invading organisms (downstream of NADPH oxidase) - catalase+ organisms clear their own H2O2.

71
Q

Glycoproteins synthesized by virally infected cells that act locally on uninfected cells - Selectively prevent viral translation

A

IFN-a and IFN-b

monocytes, macrophages, B cells, NK cells.

72
Q 
Express...
CD2
CD3 (transmit signals to cell interior)
CD4/8
CD40L
CXCR4
A

Helper T cell (Th cell) - Cellular immune response

Note - CD16/56 for NKC

73
Q 
Express...
IgG
MHCII
B7 (CD80/86) for CD28
CD40 for CD40L
CD19
CD20
CD21 for EBV
A

B cells - Humoral immune response

74
Q 
Express...
MHCII
B7 (CD80/86) for CD28
CD40 for CD40L
TLR4 (CD14) for PAMPS/endotoxins
Fc and C3b receptors
CCR5

Note - CCR5 is a G-protein chemokine receptor and requires co-binding with CD4 for HIV infection

A

Macrophages

75
Q

Cell expressing…
CD34
CD18

A

Hematopoietic stem cell

Neutrophils

76
Q

Mechanism by which T and B cells become inactivated after binding to their antigen without a costimulatory signal (signal 2) - allows for self-tolerance.

A

Anergy

77
Q

Exposures treated with preformed antibodies.

“To Be Healed Very Rapidly”

A 
Tetanus
Botulinum
HBV (+active immunization)
Varicella
Rabies (+active immunization)

Other sources of preformed antibodies include IgA in breast milk and IgG crossing placenta

78
Q

Mechanism of type I hypersensitivity - anaphylactic and atopic

Bee sting
Food allergy
Rhinitis
Hay fever
Eczema
Hives
Asthma
A

Free antigen crosslinks IgE on presensitized Mast cells and Basophils resulting in release of vasoactive amines (e.g. histamine) that act on postcapillary venules - rapid because of preformed antibodies

Subsequent delayed response due to production of leukotrienes, prostaglandins, and cytokines by eosinophils

Test for using skin test

79
Q

Mechanism of type II hypersensitivity - cytotoxic/targeted

Includes most inherited and acquired tissue specific hypersensitivities (e.g. hemolytic reactions/diseases)

A

Antibody (IgM, IgG) mediated cellular destruction by NKs, Neutrophils, Macrophages, and Eosinophils…
Opsonization and phagocytosis
Complement/Fc mediated inflammation
Antibody-mediated inactivation

Direct Coombs’ detects antibodies that have adhered to a patient’s RBCs using antihuman antibodies (test Rh+ infant)

Indirect Coomb’s detects antibodies that can adhere to other RBCs (test Rh- mother)

80
Q

Mechanism of type III hypersensitivity - immune complex /systemic

Arthus reaction
SLE
Polyarteritis nodosa
Post-strep glomerulonephritis
Serum sickness
A

Antigen-antibody complex activates complement, which attracts Neutrophils and causes local inflammation

Test for using immunofluorescent staining

81
Q 
5-10 days after antigen exposure...
Fever
Urticaria
Arthralgia
Proteinuria
Lymphadenopathy
A

SERUM SICKNESS

Type III hypersensitivity in which antibodies to foreign proteins are produced - often caused by drugs

82
Q

Following intradermal injection of antigen into a presensitized individual…
Edema
Necrosis

A

ARTHUS REACTION

Local subacute type III hypersensitivity reaction

83
Q

Mechanism of type IV (delayed) hypersensitivity - Cell mediated (T-cell, Macrophages)

Contact dermatitis (poison ivy, nickel allergy)
TB skin test
GVHD
Granulomatous inflammation
Multiple sclerosis
A

Sensitized T cells encounter an antigen and release cytokines leading to macrophage activation - does not involve antibodies and not transferable by serum

Test with patch test (e.g. TB test)

84
Q 
Blood transfusion followed by...
Urticaria
Pruritus
Wheezing
Fever
A

Type I hypersensitivity - Allergic reaction against plasma proteins in transfused blood

Treat with antihistamines

85
Q 
Blood transfusion followed by...
Dyspnea
Bronchospasm
Hypotension
Shock
Cardiac arrest
A

Type I hypersensitivity - Anaphylaxis against IgA in IgA-deficient patients (require washed RBCs)

Treat with epinephrine

86
Q 
Blood transfusion followed by...
Fever
Headache
Chills
Flushing
A

FEBRILE NONHEMOLYTIC TRANSFUSION REACTION

Type II hypersensitivity - Host antibodies against donor HLA antigens and WBCs

87
Q 
Blood transfusion followed by...
Chest or back pain
Fever
Hypotension
Tachypnea
Tachycardia
Hemoglobinuria (intravascular hemolysis)
Jaundice (extravascular hemolysis)
A

ACUTE HEMOLYTIC TRANSFUSION REACTION

Type II hypersensitivity - ABO incompatibility (intravascular)

88
Q

Anti-basement membrane

A

Goodpasture syndrome

89
Q

Anti-centromere

A

Limited scleroderma (CREST)

90
Q

Anti-glutamic acid decarboxylase (GAD-65)

A

T1DM

91
Q

Anti-desmoglein (anti-desmosome)

A

Pemphigus vulgaris

92
Q

Anti-hemidesmosome

A

Bullous pemphigoid

93
Q

Anti-Jo-1, anti-SRP, anti-MI-2

A

Polymyositis, dermatomyositis

94
Q

Anti-microsomal, antithyroglobulin

A

Hashimoto thyroiditis

95
Q

Anti-mitochondrial

A

Primary biliary cirrhosis (PBC)

96
Q

Anti-phospholipase A2 receptor

A

Primary membranous nephropathy

97
Q

Anti-scl-70 (anti-DNA topoisomerase II)

A

Scleroderma (diffuse)

98
Q

Anti-smooth muscle

A

Autoimmune hepatitis type 1

99
Q

Anti-SSA, anti-SSB (anti-Ro, anti-La)

A

Sjogren’s

100
Q

IgA anti-endomysial, IgA anti-tissue transglutaminase

A

Celiac disease

101
Q

MPO-ANCA/p-ANCA

A

Microscopic polyangiitis

Eosinophilic granulomatosis with polyangiitis (Churg-Strauss)

102
Q

PR3-ANCA/c-ANCA

A

Granulomatosis with polyangiitis (Wegener)

103
Q 
Rheumatoid factor (IgM targeting IgG-Fc)
Anti-CCP (specific)
A

Rheumatoid arthritis

104
Q

After 6 months…
Pyogenic infections
Enteroviruses
Giardia

Absent B cells on peripheral smear (CD19 or CD20)
Decreased IgA, IgM, IgG
Absent/scant lymph nodes and tonsils

A

X-LINKED (BRUTON’S) AGAMMAGLOBULINEMIA

X-linked recessive (common in boys)

Defect in BTK (tyrosine kinase) leads to deficient B-cell maturation

105
Q

Airway and GI infections
Autoimmune disease (e.g. Celiac)
Atopy
Anaphylaxis to transfusion

Decreased IgA
Normal IgM, IgG

A

SELECTIVE IGA DEFICIENCY

106
Q 
Can be acquired in 20s and 30s
Bronchiectasis
Sinopulmonary infections
Autoimmune disease
Lymphoid hyperplasia of the intestines

Decreased plasma cells
Decreased IgA, IgM, IgG

A

COMMON VARIABLE IMMUNODEFICIENCY

107
Q 
Tetralogy of Fallot/Truncus arteriosus
Abnormal facies
Recurrent viral and fungal infections
Cleft palate
Tetany

Decreased T cells
Decreased PTH
Hypocalcemia
Absent thymic shadow on CXR

A

THYMIC APLASIA (DIGEORGE SYNDROME)

Diagnosed by 22q11 deletion on FISH - failure to develop 3rd and 4th pharyngeal pouches leads to absent thymus and parathyroids

B lymphocytes are adequate (CD20+)
T lymphocytes are low (CD3+) - which are important in signaling B cells to develop into antibody producing plasma cells

Thus at risk for viral, bacterial, and fungal infections

108
Q

Disseminated mycobacterial and fungal infections - May be precipitated by BCG vaccine

Decreased IFN-y

A

IL-12 RECEPTOR DEFICIENCY

Autosomal recessive deficiency in IL-12 - Prevents dimerization of Janus Kinase (STAT1)

109
Q

Coarse facies
Noninflamed staph abscesses
Retained primary teeth
Eczema

Increased IgE
Decreased IFN-y

A

AUTOSOMAL DOMINANT HYPER-IgE (JOB) SYNDROME

STAT3 mutation leads to deficiency of Th17 cells - impaired recruitment of neutrophils to sites of infection

110
Q

Noninvasive candida albicans infections of skin and mucous membranes

Absent in vitro T-cell response to candida antigens
Absent cutaneous reaction to candida antigens

A

CHRONIC MUCOCUTANEOUS CANDIDIASIS

T-cell dysfunction

111
Q 
Failure to thrive
Chronic diarrhea
Recurrent viral and opportunistic infections
Candidasis
Anergy

Decreased T-cell receptor excision circles
Absent thymic shadow on CXR
Absent germinal centers in lymph nodes
Absent T cells (lymphopenia)
Nonfunctional B cells (hypogammaglobulinemia)

A

SEVERE COMBINED IMMUNODEFICIENCY

Defective IL-2 (X-linked)
Defective Adenosine Deaminase deficiency (autosomal recessive)

Bone marrow transplant - no concern for rejection

Because lymphoid progenitor cells affected –> low B (CD20+) and T cells (CD3+)

112
Q

Ataxia
Telangiectasia
Cerebellar atrophy
Malignancy risk

IgA deficiency –> repeated sinupulmonary infections
Increased AFP
Combined B/T cell defect

A

ATAXIA-TELANGIECTASIA

Defect in ATM gene - Inability to repair dsDNA breaks (ionizing radiation) leads to cell cycle arrest

113
Q

Failure to thrive
Recurrent sinopulmonary/GI infections
Opportunistic infections (Pneumocystis, Cryptosporidium, CMV)
lack of IgG increases risk of encapsulated bacterial infection

Normal or increased IgM
Very decreased IgA, IgG, IgE

A

HYPER IGM SYNDROME

X-linked recessive

Defective CD40L on T helper cells leads to defective immunoglobulin gene rearrangement/class switching

114
Q

Recurrent infections worsening with age (>6 mos)
Bleeding (Thrombocytopenia)
Eczema

Small, decreased platelets
Combined B/T cell defect

A

WISKOTT-ALDRICH SYNDROME

X-linked recessive

Mutation in WAS - Actin cytoskeletal defect in T cells

115
Q

Recurrent bacterial skin and mucosal infections
Absent pus formation
Impaired wound healing
Delayed separation of umbilical cord (>30 d)

Increased neutrophils
Absence of neutrophils at infection site

A

LEUKOCYTE ADHESION DEFICIENCY TYPE 1

Autosomal recessive

Defect in LFA-1 product integrin-b2 (CD18) leads to impaired migration and chemotaxis

116
Q

Recurrent pyogenic infections by staph/strep
Partial albinism
Peripheral neuropathy
Progressive neurodegeneration

Pancytopenia
Giant granules in granulocytes and platelets

A

CHEDIAK-HIGASHI SYNDROME

Autosomal recessive

Defect in lysosomal trafficking regulator gene (LYST) - Microtubule dysfunction and phagosome-lysosome fusion

117
Q 
Increased susceptibility to catalase+ organisms...
Lungs
Skin
Lymph nodes
Liver

Recurrent bacterial infections

(“New LiBrary SPACES”)

Abnormal dihydrorhodamine test (decreased green fluorescence)
Lower blue score in nitroblue tetrazolium dye reduction test

A

CHRONIC GRANULOMATOUS DISEASE

X-linked recessive - Defect in NADPH oxidase decreases superoxide and respiratory burst in neutrophils

Treat with IFN-y

Nocardia
Listeria
Burkholderia cepacia
Staphylococcus
Pseudomonas
Aspergillus
Candida
Enterobacteriaceae (E. coli, Serratia)
118
Q

Within minutes to hours…
Arterial fibrinoid necrosis
Capillary thrombotic occlusion
Gross mottling and cyanosis

A

HYPERACUTE REJECTION

Type II hypersensitivity - Pre-existing recipient antibodies react to donor antigen and activate complement

Graft must be removed

119
Q

Within weeks to months…

Endotheliitis with lymphocytic infiltrate

OR

Necrotizing vasculitis with neutrophilic infiltrate and C4d deposition

A

ACUTE REJECTION

Type IV hypersensitivity - CD8+ T cells activated against donor MHCs

Note - May also be humoral (Type II; antibodies develop after transplant) as well

Prevent/reverse with immunosuppressants

120
Q

Within months to years…
Proliferation of vascular smooth muscle
Parenchymal atrophy and interstitial fibrosis
Dominated by atherosclerosis

Bronchiolitis obliterans (lung)
Accelerated atherosclerosis (heart)
Chronic graft nephropathy (kidney)
Vanishing bile duct syndrome (liver)

A

CHRONIC REJECTION

CD4+ T cells respond to recipient APCs presenting donor peptides (e.g. allogeneic MHC) - both cellular (type II) and humoral (type IV) hypersensitivity

121
Q 
Transplant patient (liver or bone marrow) with...
Maculopapular rash
Jaundice
Diarrhea
Hepatosplenomegaly
A

GRAFT VERSUS HOST DISEASE

Grafted immunocompetent T cells proliferate in immunocompromised host and reject host cells with “foreign” proteins leading to severe dysfunction - type IV hypersensitivity

In bone marrow transplant may be potentially beneficial - graft versus tumor effect

122
Q

Mechanism of immune response to parasites

A

Th2 cells and mast cells produce IL-5
IL-5 induces eosinophils
Eosinophils bind to IgE on parasite and release major basic protein and ROS
Antibody-dependent cell-mediated cytotoxicity
Antigen presentation via MHCII

123
Q

Main opsonins of the immune system

A

IgG

C3b

124
Q

Mechanism of NF-kB action

A

Growth factor mitogens, Cytokine-TNFR binding, or antigen-TLR binding

IkB kinase phosphorylates IkB

NF-kB released and enters nucleus leading to transcription of inflammatory and proliferative genes

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