Immuno Flashcards
Allergic rhinitis
Loss smell, nasal itching and discharge, swollen and hyperemic nasal mucosa.
Tx with corticosteroid spray (fluticasone) +/- PO antihistamines
Hereditary angioedema
Laryngeal edema, abdo sxs (pain, D&V, constip, distension), ?swelling hands and feet.
Triggered by infections, stress, menstruation, ACEI
Acute urticaria
Urticarial vasculitis
Ecchymoses and hyperpigmentation may occur in healing process
Biopsy for dx
Classic urticaria reaction
Latex
Which Ig is a dimer?
IgA
Which Ig is most abundant?
IgG
Chemotactic agents
IL8, LTB4, C5a, bacterial products, kallikrein
Kostmann’s
Congenital neutropenia
Examples of Type II HSR
Hemolytic anemias Graves Goodpastures ITP Myasthenia Gravis Type I DM
Examples Type III HSR
SLE HCV-associated MPGN RA Polyarteritis nodosa Arthus reaction Serum sickness
c-ANCA
Wegener’s
p-ANCA
Polyarteritis nodosa
Microscopic polyangitis
Live vaccines
MMR BCG Yellow fever Oral polio (Sabin) VZV
Killed vaccines
Rabies
Influenza (IM)
Polio (salk)
HAV
Subunit/congugate vaccine
Pneumococcal
Congugate vaccine
Hib
Recombinant vaccine
HBV
Detoxified vaccine
Tetanus
Inactivated bacterial preparation vaccine
Whole cell typhoid
Alum
Agent that produces predominantly Ab response through release IL-4 which primes naive B cells
Vaccination: active or passive immunity
Active
Immune globulin: active or passive immunity
Passive
Innate immunity composed of?
Epithelium
Mucus
Complement
Myeloid cells: granulocytes, macros, mast cells
TLRs
On cells of innate immune system.
Recognize PAMPs, e.g. CD14 (on macros) is a TLR that recognizes LPS on gram neg bacteria
TLR activation
Upregulates NF-KB
NF-KB
“On switch for acute inflamm response”
Which products of AA mediate vasodilation and increased vascular permeability?
PGI2, PGD2, PGE2
Mediate neutrophil chemotaxis
LTB4, IL8, C5a, bacterial products, kallikrein
Which AA products mediate vasoconstriction, bronchoconstriction, and increased vascular permeability?
LTC4, LTD4, LTE4
Activators or mast cells
Tissue trauma
C3a, C5a
Cross linking of IgE by antigen
Immediate response of mast cells
Histamine release:
- arteriole vasodilation
- increased vascular permeability at post-cap venule
Delayed response of mast cells
Production AA metabolites, esp LTs
Classical pathway complement
C1 bings IgG or IgM that is bound to an antigen
Alternative pathway complement
Microbial products directly activate
Mannose lectin binding pathway complement
MBL binds mannose on microorganisms
All complement pathways meet where
Production C3 convertase, C5 convertase
Complement proteins that trigger mast cell degranulation
C3a, C5a
Complement protein that acts as opsonin for phagocytosis
C3b
Hageman factor
Inactive pro-inflamm protein produced by liver.
Activated on exposure to subendothelial or tissue collagen
Activates coag and fibrinolytic systems, complement, kinin system
IMPORTANT IN DIC!!!
Bradykinin functions
Vasodilation
Increased vascular permeability
Pain
Pain mediators
Bradykinin, PGE2
Sensitize sensory nerve endings
Rubor and Calor
Due to vasodilation causing increased blood flow
HISTAMINE, PGs, bradykinin
Tumor
Leakage fluid at post-cap venule into interstitial space
Histamine, tissue damage
Fever mechanism
Pyrogens cause release IL1, TNF which increase COX activity in perivascular cells of hypothalamus. Increased COX=increased PGE2 which increases temp set point
Steps of neutrophil arrival
- Margination
- Rolling
- Adhesion
- Transmigration
- Phagocytosis
- Destruction phagocytosed material
Rolling-mechanism
Selectin speed bumps.
P selectin from Weibel Palade bodies, histamine mediated.
E selectin induced by TNF, IL1
Adhesion-mechanism
Cellular adhesion molecules (CAMS) (on endothelium) and integrins (on neutrophils) bind
Upregulators CAMS
TNF
IL-1
Upregulators integrins
C5a, LTB4
Leukocyte adhesion deficiency
AR defect in CD18 subunit of integrin
Thus no adhesion
Sxs/signs: delayed separation umbilical cord, neutrophilia, recurrent bacterial infections without pus
Chediak Higashi disease
Protein trafficking defect (microtubules)-phagosome can't bind with lysosome Sxs: Pyogenic infections Neutropenia (can't divide) Giant granules by Golgi Defective primary hemostasis Albinism Peripheral neuropathy
O2 dependent killing
Most effective Generates HOCl (O2 -> superoxide ->H2O2 ->HOCl
O2 independent killing
Less effective
Via enzymes in leukocyte: lysozyme, major basic protein
CGD
NADPH oxidase defect
Infections and granulomas with catalase positive organisms
Nitro-blue tetrazolium test (NBT) remains colorless
Catalase positive organisms
S aureus Pseudomonas cepacia S marcescens Nocardia Aspergillus
MPO deficiency
MPO converts H2O2 to HOCl.
In theory similar to CGD but reality: only increased risk Candida
When in inflamm do macros peak
2-3 days after start inflamm
When in inflamm do neutrophils peak
24 hrs after start inflamm
How do macros get from blood into periphery
Same way neutrophils do (margination, rolling, adhesion, transmigration)
Method by which macrophages kill
O2 INdepedent, esp lysozyme
Outcomes acute inflamm
Resolution and healing (IL10, TGF-B)
Continued acute inflamm (macros call in more neuts via IL-8)
Abscess formation
Chronic inflamm
Chronic inflamm cells
Lymphos and plasma cels
Stimuli for chronic inflamm
Persistent infection (MCC) Viruses, mycobacteria, parasites, fungi AI Foreign material Some cancers
T cell activation requirements
- Binding antigen/MHC complex
2. Secondary signal
Types CD4+ cells
TH1, TH2
TH1 products
IL2, IFN-gamma
IL2
T cell growth factor
IFN-gamma
Macrophage activator
TH2 products
IL4
IL5
IL10
IL4
IgE
IL5
IgA
IL10
Inhibits TH1
CD8+ cells
Perforins, granzyme
Express FasL which binds Fas on target cell
First Igs on B cell
IgD, IgM
Granuloma-key feature
Epitheliod histiocyte
Ddx-non-caseating granuloma
Foreign material, e.g. leaking breast implant Sarcoidosis Berylliosis Crohns Cat scratch (stellate shaped)
Ddx-caseating granuloma
TB
Fungus
DiGeorge syndrome
Developmental failure 3rd and 4th pharyngeal pouch
22q11 microdeletion
T cell deficiency, hypocalcemia, abnormalities great vessels, heart, and face
T cell deficiency symptoms
Viral and fungal infections
B cell deficiency symptoms
Bacterial, protozoal infections
3rd pharyngeal pouch
Inferior parathyroids, thymus
4th pharyngeal pouch
Superior parathyroids
SCID
Defective cell-mediated and humoral immunity. All the infections, including opportunistic. Etiologies: 1. Cytokine receptor defects 2. Adenosine deaminase deficiency 3. MHC class II deficiency
Tx-sterile isolation, stem cell transplant
Cell-mediated immunity
T cells
Humoral immunity
B cells
X linked agammaglobulinemia
Complete lack Igs due to disordered B cell maturation
Bruton tyrosine kinase (BTK) mutation
Infections with bacteria, enterovirus, Giardia
Avoid live vaccines
Common variable deficiency
Low Ig due to B cell or TH cell defects
(Exams: mutation MHC III)
Bacteria, enterovirus, Giardia infections
Increased risk AI disorders, lymphoma
Which two immunodeficiencies result in bacterial, enterovirus, and Giardia infections?
Common variable X linked (Bruton) agammaglobulinemia
Most common Ig deficiency
IgA
IgA deficiency
Mucosal infections, esp viral.
NB: celiacs tend to have this a lot
Hyper-IgM syndrome
Mutation in CD40L or CD40R...problem with class switching-no 2nd signal. Decreased IgA, IgG, IgE causes recurrent infections, esp mucosal
Wiskott Aldrich syndrome
Defect in WASP (Wiskott-Aldrich Syndrome Protein)
Thromboytopenia, eczema, recurrent infections (humoral and cell mediated)
X linked
C5-C9 deficiency
Neisseria infections
C1 inhibitor deficiency
Hereditary angioedema (esp periorbital edema). Excess activation complement (therefore vasodilation and increased vascular permeability)
Primary mech for autoimmunity
Loss of self tolerance: many self-reactive lymphos regularly generated but undergo TOLERANCE (central and peripheral). E.g. negative selection in thymus causes self-reactive lymphos to undergo apoptosis
AIRE mutation
AI polyendocrine syndrome (APECED): hypoparathyroidism, adrenal failure gonadal failure, alopecia, vitiligo, candida.
Failure of negative selection: no AIRE to express “self”.
AIRE is also called “autoimmune regulator”
Central tolerance in bone marrow
Negative selection: if bind “self” too strongly, either undergo receptor editing or apoptosis
Peripheral tolerance
In blood. Anergy (no second signal) or apoptosis via Fas death receptor
ALPS
Autoimmune Lymphoproliferative Syndrome
Mutation in Fas apoptotic pathway
Cytopenias, LAD, HSM (LAD and HSM due to proliferation lymphos….can lead to lymphoma)
FOXP3 mutation
IPEX syndrome
IPEX syndrome
Immune dysfn Polyendocrinopathy Enteropathy X linked
Polyendo–thyroiditis, diabetes
Enteropathy–diarrhea
CD25 polymorphisms
Associated with autoimmunity, e.g. MS, Type I diabetes
HLA B27
Ankylosing spondylitis
Environmental triggers for autoimmunity
Infection (self reactive activated) Molecular mimicry (antigen resembles self-antigen)
Reason for female bias in autoimmunity
Esrogen decreases tolerance, therefore more self-reactive lymphocytes
SLE
Type III HSR
Decreased levels CH50, C3, C4
ANA, anti-dsDNA, anti-Sm
Drug induced lupus
Hydralazine, procainamide, isoniazid
Anti-histone Abs
CNS, renal involvement rare
Antiphospholipid syndrome
Abs + hypercoagulable state
Lifeling anticoagulation–arterial and venous thromboses
Can occur with SLE but more commonly is primary disorder
Sjogrens
AI destruction lacrimal, slaivary glands
Type IV HSR
Anti-SSA, SSB, ANA, RF
Increased risk B cell lymphoma (U/L enlargement parotid)
Systemic sclerosis
Fibroblast activation causing collagen deposition. Massive amounts fibrosis Limited type (CREST) and diffuse type
CREST syndrome antibody
anti-centromere
Diffuse systemic sclerosis Ab
anti-topoisomerase I
Mixed connective tissue disease–Antibodies
Anti U1 RNP antibodies
Labile tissues
Continuously cycle to regenerate tissue.
Small and large bowel
Skin
Bone marrow
Stable tissues
Quiescent but can re-enter cell cycle.
LIVER
Permanent tissues
Heal by repair; no regenerative capacity
Myocardium
Skeletal muscle
Neurons
Initial phase repair
Formation of granulation tissue
Granulation tissue mediators
Fibroblasts, capillaries, myofibroblasts
Scar formation
Result of repair
Type III collagen replaced by Type I
Causes delayed wound healing
Infection (MCC)
Vit C, Cu, Zn deficiency
Foreign body/continued inflamm, diabetes, ischemia, malnutrition
Hypertrophic scars
Excess production of Type I collagen
Keloid scars
Excess production scar tissue out of proportion to wound
Type III collagen
*Earlobe
Bare lymphocyte syndrome
Deficiency in MHC I or MCH II
Low IgA, IgG
Associated with sclerosing cholangitis (hepatomegaly, jaundice)
IFN-gamma deficiency
Can’t form granulomas
TB
And salmonella, for some reason
OKT3
Aka muromonab.
Monoclonal antibody (mAb) against CD3.
Treats rejection episodes in transplant pts, by clearing T cells from circulation.
Use when acute steroid-resistant rejection of heart, liver, kidney transplants
Cyclosporin
- MOA
- SE
Inhibits calcineurin (therefore T cells) SE: gum hypertrophy
Azathioprine
-Mech
Metabolized to 6MP. Prevents DNA synthesis, esp lymphocytes
Sirolimus
Aka rapamycin
Inhibits T cell prolif by binding FK-binding protein 1A (FKBP-1a)
Anti-Jo1
Dermatomyositis
Anti-smooth muscle
AI hepatitis
Anti-centromere
CREST syndrome
Anti-topoisomerase I
Diffuse scleroderma
Antimitochondrial
PBC
Anti-glutamic acid decarboxylase
T1DM
Anti-endomysial
Celiac
Anti-cardiolipin
Antiphospholipid
SLE
Syphilis
Goodpastures
Against Type IV collagen.
Pulm, renal sxs (bleeding)
Immunofluoresence
Myelin basic protein, proteolipid protein
Implicated in MS
Stony fruits
Associated with oral allergy syndrome
SLE treatment when steroids fail
Cyclophosphamide
Abatacept
CTLA4-Ig fusion protein
Used in RA
Mycophenolate
Inhibits IMP DH (guanine synthesis).
Transplant alternative to cyclophosphamide
Also used in AI diseases, vasculitides
Denosumab
Anti-rank L
used in osteoporosis
Basiliximab
mAb against IL-2alpha
Rituximab
Anti-CD20
Efalizumab
mAb against CD11a
Ustekinumab
mAb to p40 subunit IL-12, IL-23.
Psoriatic arthritis
Kveim test
Tests for sarcoidosis.
Not used in UK due to infection risk (involves placing sample of sarcoid pt’s spleen intradermally into pt and biopsying in 4-6 weeks to see if caseating granulomas)
Latex fixation test
Used for rheumatoid factor
Increased CD50
Acute or chronic inflamm
HLA-DQ2
Celiac
HLA-B27
Ank spon
HLA-DR2
Goodpasture’s
HLA-DR3
Graves, MG, SLE
HLA-DR4
T1DM
RA
Serum tryptase levels
Useful in diagnosing anaphylaxis
Anti-desmoglein 1,3
Pemphigus vulgaris
Isograft
Between twins
Hyperacute rejection
Minutes to hours.
Preformed Abs
Acute rejection
~1 week
Type IV HSR
Chronic rejection
Months-years
gp120
Envelope
Binds CXCR4 on surface CD4+ cell to gain entry
Initial step in HIV infection
gp41
Penetrates CD4+ wall
Tx for myasthenic crisis
Plasmapheresis
Natalizumab
mAb against alpha4 integrin (T cell migration)
Tocilizumab
mAb against IL-6
Castleman’s, RA
Adalimumab
Fully humanized mAb to TNF-a
Speckled immunofluroescence pattern
Anti-Jo1
Anti-Sm
Anti-RNP
Anti-Ro
Nucleolar immunofluorescence pattern
anti-RNA polym (systemic sclerosis)
Peripheral immunofluorescence pattern
anti-dsDNA
Seronegative spondylarthropathies
Ank spon
Enteropathic arthritis
Psoriatic arthritis
Reactive arthritis
anti-1A-2 and anti-phogrin antibodies
Diabetes
Against tyrosine phosphatase
Hashimoto’s antibodies
anti-thyroid peroxidase
anti-thyroglobulin
Kearns-Sayre syndrome
Initially eye stuff (ptosis, difficulties with eye movement, pigmentation retina), then prox muscle weakness, cardiac conduction defects, hearing loss, cerebellar ataxia
Hypoparathyroidism, primary gonadal failure, DM, hypopituitarism
Hirata’s disease
Auto-Abs to serum insulin
Fasting hypoglycemia
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