A/26-33 IMMUNPATHOLOGY (Tamer) Flashcards

1
Q

how fast does type 1 hypersensitivity reaction occur?

A

occurs rapidly -within minutes

may be local and appear as an annoying response to hay fever (allergic rhinitis) or severly weakening the individual during asthma /in a fatal systemic disorder (anaphylaxis)

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2
Q

give the sequence of events during first exposure to allergen

A
  • APC takes up the allergen and presents it via MHC 2 to CD4 + TH2
  • When CD4+ TH2 cells are active they secrete cytokines and immunoglobulins. e.g. IL-4,IgE,IL-5,IL-13
  • mast cells bind Fc portion of IgE
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3
Q

list the cytokines and immunoglobulins secreted during the first exposure to an allergen

A

CD4+ TH2 cells secrete :

IL-4 –> Specific B-cells –>IgE

IL-5-->Activates eosinophils

IL-13 –> Epithelial cells –> mucus secretion

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4
Q

what happens in the 2nd exposure to the SAME allergen ?

A
  • allergen binds IgE on mast cells –>biochemical signals –>mast cells secrete the following :
  • *Vasoactive amines :**
  • Histamine
  • Adenosine
  • Proteases
  • Kinins

LIpid mediators:

Primary:

  • prostaglandins
  • leukotrienes

*Secondary (late-phase reaction ,2-8 hrs later) :

-*
Neutrophils
-Lymphocytes
-Leukotrienes B4
-Eosinophils –>Release toxins to epithel–>necrosis

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5
Q

what are the two types of anaphylaxis ?

A
  • systemic anaphylaxis
  • local anaphylaxis
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6
Q

describe Systemic anaphylaxis

A

-due to protein antigen (bee sting) /drug (penicillin)

symptoms : itching , hives , skin erythema, respiratory difficulty , vomiting , diahrrea, abdominal crumps

-ARDS in the lung

practically we observe Laryngeal , ARDS, General **edemas

anaphylactic shock without intervention**

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7
Q

describe Local anaphylaxis and give at least 3 examples

A
  • when antigen is limited within a particular site
    e. g.
  • allergic rhinitis (Hay fever , home dust , animal hair)
  • itching skin
  • food allergy
  • asthma bronchiale
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8
Q

Give the clinical picture of Asthma

A

chronic inflammatory disorder of the airways .

the asthma triad

1) reversible airway obstruction
2) airway inflmmation (bronchial)
3) bronchial smooth muscle hypertrophy, hyperressponsiveness

symptoms include : wheezing ,coughing,dyspnea,chest tightness

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9
Q

how do the pathology cock-sucking bitches classify Asthma?

A

The classification of Asthma is as follows :

1) extrinsic/atopic -70% of cases

type 1 hypersensitivity

2) intrinsic/non-atopic- 30% of cases

triggered by non-immune stimuli
e.g. aspirin, cold,psychological stress

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10
Q

pathogenesis of Asthma

A

-begins in childhood

1) first exposure to an allergen :

APC takes up allergen –> CD4+ TH2 cells secrete:

IL-4 –> Specific B-cells –>IgE
IL-5
IL-13
-IgE binds mast cells
——————————————————————————–
2) 2nd exposure to an allergen (allergen triggered asthma)

A) Acute immediate response

allergen binds IgE on mast cells –>biochemical signals –>mast cells secrete the following :

  • *-Leukotrienes** C,D,E
  • *-Prostaglandins** D2
  • *-Histamine**
  • Ach
  • PAF
  • these mediators open intercellular junctions–> more antigens enter airways and bind mast cells
  • antigen directly causes vagal stimulation that leads to bronchoconstriction
  • edema and mucus secretion are present

B) Secondary (late-phase reaction ,2-8 hrs later) :

mast cells release additional cytokines –> influx of other leukocytes , mainly eosinophils which then release protein toxins that amplify the response

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11
Q

asthmatic attacks are preceded by what ?

A
  • allergic rhinitis
  • urticartia /eczema
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12
Q

what are the most common antigens that cause Asthma ?

A

-dust
-pollen
-animal dander
(tiny particles of skin that had been shed from animals)

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13
Q

describe the micro-morphology of Asthma

A

“Always On TIME”

  • Atelectasis (collapsed pulmn. parenchyma)
  • Overdistention due to overinflation

-Thickening of the basement membrane
Increases size of Mucus glands
-Mucus plugs in bronchi
(Cruschmann spirals /Charcot-Leyden crystals )
-Edema and inflammatory infiltration

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14
Q

clinical course of Asthma

A

air struggles to get out –> destruction of septa–> emphysema--> capillary diameter decrease–> more effort to pump blood out –> **cor pulmonale

more frequent attacks -higher risk for emphysema and cor pulmonale . aim is to prevent frequent attacks**

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15
Q

type 2 hypersensitivity - basic definition

A

caused by antibodies generated against endogenous/exogenous antigens

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16
Q

what are the consequences of type 2 hypersensitivity reaction

A

1) opsonization - cells are tagged with antibodies and are phagocytosed (IgG, c3b)
2) complement activation : via the classical pathway and formation of MAC

3) Antibody mediated cellular dysfunction :
*no cell injury/inflammation*

  • Myasthenia Gravis - antibodies against Ach receptors –>muscle weakness
  • Graves Disease- antibodies againsy TSH receptors–>hyperthyroidism
  • ​RH-incompatibility -

Mom RH+ Fetus RH-
Blood Mix –>Antibodies Generated–> 2nd Child Screwed–> EDEMA, HYPOXIA , JAUNDICE ,ICTERUS

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17
Q

type 3 hypersensitivity reaction what means dat?

A

“systemic immune complexes disease”

include formation of antigen-antibody complexes and
their deposition in blood vessels and several organs (systemic) or in a particular organs (localized)

anitgens can be endogenous/exogenous

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18
Q

Pathogenesis of type 3 hypersensitivity reaction

A

ag-ab complexes formation in circulation –>

deposition in various tissues –>

inflammatory reactions and complement activation (c3a,c4a,c5a)

  • complexes also cause platelet aggregation and activation of factor 12 (hageman) –> microthrombi
  • ->ischemia
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19
Q

Name at least 3 diseases associated with type 3 hypersensitivity reaction

A
  • reactive arthritis
  • post strep. glomerulonephritis
  • Systemic lupus erythematosus
  • vasculitis
  • Polyarteritis nodosa
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20
Q

descrive the micro-morphology of type 3 hypersensitivity reaction

A
  • fibrinoid necrosis (protein deposition)
  • microthrombi , ischemic necrosis
  • acute inflammation
  • fibrosis
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21
Q

Give and example of local immune complex disease

A

Arthus reaction -
results from acute immune complex vasculitis

inflammation and histologic appearance same as the systemic diseases but localized to one tissue/organ

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22
Q

How does a penguin build it’s house?

A

Igloos it together.

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23
Q

type 4 hypersensitivity reaction whats mean dat ?

A

T-Cell Mediated -Delayed Type Hyp.Sens

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24
Q

to which disease is the type 4 hypersensitivity reaction related to ?

A

Tuberculosis

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25
Q

pathogenesis of type 4 hypersensitivity reaction

A

1st exposure to bacteria

  • APC presents bacteria via MHC 2 –> IL-12
  • generation of TH1 and memory cells

2nd exposure

  • recruitment of TH1 and memory cells –>secretion of IFN-γ
  • macrophages secrete –> PDGF, TGFβ , IL-12 which further enhance the reaction causing Amplification Loop
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26
Q

is the Delayed Type Hypersensitivity reaction acute or chronic ?

A

Chronic -due to the amplification loop

(chronic unless the toxic agent is eliminated)

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27
Q

what can a prolonged DTH (type 4) reaction result in ? and why ?

A

Granuloma Formation

activated macrophages –> become epitheloid cells
–>fuse and form giant cells –>surrounded by lymphocytes–>Granuloma surrounded by fibroblasts and CT

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28
Q

describe the T-cell mediated response that occurs during type 4 hypersensitivity reaction

A

-APC present via MHC 1 to CD8+ T-cells –>become cytotoxic T-cells –> releases of Granzymes and Perforins–> apoptosis of target cell

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29
Q

I thought about going on an all-almond diet

A

But that’s just nuts

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30
Q

there are 2 facts regarding organ transplantation what are they ?

A

-recipient and donor have **different MHC

-**
donor cells go through Turn-Over (dying cells removed by phagocytosis) process in recipient’s body–>antigens presented as foreign

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31
Q

List 3 mechanisms of transplant ejection

A

1) T-cell mediated rejection
involves CD8+ T-cells of recipient and MHC 1 of donor
cytotoxic reaction against cell of the graft

2)Antibody mediated rejection:
dying donor cells release substances–>presented by APC’s MHC2 to CD4+ T-cells–>release of IL-4 IL-5–> Ag’s bind BCR–>B-cells become plasma cells –> Ab’s against graft cells

3)Delayed Type Hypersensitivity Rejection :

APC’s of Donor have MHC2 on them–>reconized by CD4+ T-cells –> differ. into TH1 –>release TNF, IFNγ
–>DTH reaction proceeds

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32
Q

List all the transplant rejection types

A

1) Hyperacute rejection

  • *-minutes/hours**
  • by pre-formed antibodies of recipient
  • arteritis , arteriolitis
  • thrombosis ​

2) Acute rejection
-weeks/months

A) Acute cellular -related with tubulitis ,CD4+,CD8+,Mononuclear cells –> all cause edema

3) Chronic rejection

-develops within **years

-**
doesn’t respond to immunosuppression

-charecterized by vascular changes(fibrosis) that lead to general ischemia in the organ

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33
Q

list at least 3 methods that improve graft survival

A

1) try to match between MHC of donor/recipient
2) immunosupression by corticosteroids/cyclosporins
3) Anti CD3 therapy - supress T-cell
4) interrupt costimulation B7-CD28 between APC and T-cell

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34
Q

What is the downside of Immunosupression?

A

increase the risk for viral infection

e. g.
* EBV,HPV,Herpes ​

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35
Q

what are the two types of transplantation

A
  • organ transplantation
  • Bone marrow transplantation
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36
Q

what are the two types of Bone marrow transplantation

A

1) Autologus:
- stem cells are from your own body

  • hematopoietic disease is treated with chemo/radiation and disappears, then we take out stem cells so in case disease came back we repopulate them and transplant .
    2) Allogenous
  • recipient recieve high doses of chemo/radiation for immunosupression since the stem cells come from a donor and might be rejected .
  • rejection is mediated by T-cells and NK cells
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37
Q

what are the possible complications of allogenic bone marrow transplantation ?

A

1) GVHD (graft versus host diease)
immunosupressd patient doesnt reject graft but the organ transplanted recognizes (via T-cells of donor organ) the patient’s body as foreign -ALLAHU AKBARRRRRRR

-acute GVHD- epithelial necrosis in skin,liver,gut

  • *-chronic GVHD**- Skin lesions that resemble systemic sclerosis and other changes that mimic autoimmune disorders
  • *2) Immunodeficiency-** increased risk for infections
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38
Q

what is immunologic tolerance ?

A

ITS MEANENN -

a state of unresponsivness to an antigen that is induced by exposure of specific lymphocytes to that antigen

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39
Q

Self Tolerance what means dat ?

A

lack of immune responsiveness to one’s own tissue antigens

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40
Q

what are the two mechanisms that prevent self reactivity ?

A
  • *1) Central Tolerance**
  • deletion of self reactive T/B cells occurs

in the Thymus epithelial cells present self antigen with self MHC to T-cells

T-Cell recognized self-antigen? OK, U DIE
T-Cell bind MHC too strong ? OK, U DIE

(apoptosis)
same Process with B-cells in Bone Marrow . they can also go through receptor editing.

  • *2) Peripheral Tolerance -**

to eliminate autoreactive cells that managed to escape

  • Anergy: inactivation of lymphocyte by interferance in B7-CD28 costimulation
  • ​Supression of T-cells by Treg via IL-10, TGFβ
  • Activation induced cell death- T-cells that get stimulated repeatedly undergo apoptisis via
    FAS-R
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41
Q

Mention genetic factors that may lead to autoimmune diseases

A

-Autoimmune diseases have a tendancy to **run in families

-**
connection between **HLA Locus/other Loci and autoimmune diseases

e.g.

HLA-B27–>**
Ankylosing spondylitis
NOD2-crohn’s disease

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42
Q

mention at least 3 principals that demonstrate the role of infection/tissue injury in autoimmune diseases

A

1) “molecular mimicry

when foreign epitope resembels epitope of
self-antigen the immune system attacks its own cells .

e. g. in post strep. Rheumatic Fever antibodies produced against the bacteria act also on Heart antigens
2) infections that cause necrosis and inflammation increase the number of Co.Stim. molecules on APC’S(e.g.B7) –> anergy breakdown and T-cell activation
3) local injury -causes release of self antigens

4)“epitope spreading”-
each antigen has several epitopes that are presented in the thymus during selection. BUT some aren’t presented so the T-cells that recognize them didn’t undergo apoptosis . if injury happens and this epitope is released autoreactive T-cell might recognize it and get activated.

43
Q

Give a general description of Systemic Lupus Erythematosus (SLE)

A

-failure to maintain self tolerance followed by generation of autoantibodies

-Systemic disease that involves several organ systems.
(skin , kidney,serous membranes ,joints, heart)

-more common in women than men (9:1)

44
Q

which autoantibodies are produced in SLE ?

A
  • AntiNuclearAntibodies (DNA,Histones,Nucleolar….etc)
  • Antibodies against RBC’S , WBC’S ,Platelets
  • Antiphospholipid antibodies (e.g. anticardiolipin)-lead to arterial / venous thrombosis !
45
Q

pathogenesis of SLE

A

-genetic variables-Susceptibility genes
code for T/B cells specific for self nuclear antigens and do not tolerate them bitches.

  • non-genetic variables -External triggers
    (e. g. UV-radiation) which interferes with clearance of self nuclear antigens thus they increase. T/B Cells fail to tolerate them
  • formation of autoantibodies against RBC’s , WBC’S, platelets -Type 2 hypersensitivity
  • formation of Ab (ANA)-Ag complexes - type 3 hypersensitvity
46
Q

mention at least 5 morphological charechteristics of SLE

A

1) Kidney-Most important feature of SLE
immune complexes deposition and development of glomerulonephritis . there are 5 classes of patterns.

2)Joints- mononuclear infiltration of synovial membranes ,shance for cartilage destruction, joints swell

3)Skin-erythromatous rash with butterfly pattern worsens under exposure of UV-light

4)Heart- Endo,Myo,Peri-carditis, “Libman-Sacks” mitral valve

5) reaction in vessels - Acute necrotizing Vasculitis ,fibrinoid necrosis , narrowing lumen
(acute+chronic stages)

6)CNS- ischemia may cause neuropsychiatric manifestations

7)Serous membranes- inflammation of pleura,pericardium

8)Spleen- splenomegaly , follicular hyperplasia,
in histo onion skin lesions !

47
Q

what are the 5 patterns of glomerular diseases in SLE ?

A

CLASS 1 - normal (rare)
CLASS 2 - Mesangial lupus glomerulonephritis
CLASS 3 - Focal proliferative glomerulonephritis

  • *CLASS 4-Diffuse Proliferative** glomerulonephritis
  • *most serious** , most common ,effects all the glomerulus hemat+protein URIA ,hypertension , renal insuffieciency

CLASS 5- Membranous glomerulonephritis

48
Q

mention few clinical findings of patients with SLE

A
  • young women with Butterfly rash on face
  • ANA in 100% of patient (not specific for SLE)

-Renal involvement , nephrotic syndrome,hemturia ,renal failure

  • fever (uncertain cause)
  • neuropsychiatric manifestations
49
Q

dogs can’t operate an MRI machine

A

but CATscan

50
Q

is Rheumatoid Arthritis more common in men or women ?

A

more common in women (5:1)

51
Q

in Rheumatoid arthritis which joints are affected the most ?

A
  • principally affects the small joints and mostly the
  • *P**roximal Inter Phalangeal joints (PIP)

e.g. HANDS , WRISTS, ANKLE,FEET

52
Q

Rheumatoid arthritis is a … ?

A

“SSS”

  • Systemic , chronic , inflammatory disease
  • Symmetric type of arthritis
  • Suppurative proliferative synovitis
53
Q

Chronic synovitis occurs in RA and is charechterized by what ?

A
  • synovial hyperplasia
  • inflammatory infiltration–>form lymphoid nodules
  • angiogenesis
  • neutrophils on synovial surface and **fluid - important lab finding

-**
increased osteoclastic activity (RANKL)

54
Q

name the striking feature caused by chronic synvoitis

A

PANNUS - abnormal layer of fibrovascular tissue or granulation tissue (due to inflammatory cells and others)

55
Q

upon CD4+ T-Cells activation In RheumArth. Cytokines are released leading to …?

A

1) Macrophage activation -inflammation

2) B-cell activation
antibodies, Rheumatoid Factor (IgM/IgG , Fc portion)

3) release of RANKL (osteoclast)

56
Q

what type of hypersensitivity reaction occurs in Rheumatoid arthritis ?

A

Type 3 hypersensitivity reaction

immune complexes formed from 2 antibodies (ab-ab)

57
Q

describe the pathological changes that occur during the course of progressive Rheumatoid arthritis

A
  • Erosion of articular cartilage and bone (Osteopenia)
  • Narrowing of joint space
  • permanent ankylsosis
  • destruction of tendons ,ligaments,capsule
  • radial deviation - wrist
  • ​ulnar deviation -fingers

-rheumatoid subcutaneous nodules

  • firm rounded masses on extensor forearm
  • ​Histo: Central area of fibrinoid necrosis surrounded by macrophages and granulation tissue
58
Q

Patients with erosive disease , rheumatoid nodules and high RF may exhibit …

A
  • Vasculitis , Pleuritis , Pericarditis
  • Interstitial fibrosis in lung
  • Ocular changes
59
Q

Descrive the clinical course of Rheumatoid Arthritis

A

1) Arthritis start with aching pain and morning stifness of joints (improves with physical activity) and as the joints gets bigger complete ankylosis develops
2) Vasculitis can lead to Raynaud Phenomenon- spasm of arteries cause episodes of reduced blood flow to the fingers.
3) Might lead to (secondary) Reactive Amyloidosis (SAA–>AA)

60
Q

Juvenile Rheumatoid arthritis usually occurs in …

A

Chronic idiopathic arthritis that usually occurs in children

61
Q

mention 2 differences between Adult Rheumatoid arthritis and Juvenile Rheumatoid arthritis

A

-in Juvenile Rheumatoid arthritis

  • RF is absent
  • ​​Rheumatoid Nodules are absent
  • ​Larger joints can be involved
62
Q

There’s a connection between Juvenile Rheumatoid arthritis and … ?

A

HLA-B27

63
Q

there is a link between Rheumatoid arthritis and …

A

HLA -DR4

64
Q

I HATE JOKES ABOUT GERMAN SAUSAGES

A

THEY’RE THE WURST !

65
Q

Sjögren syndrome is an autoimmune disease charechterised by destruction of ….

A

-Lacrimal and Salivary glands

66
Q

if a 35-45 y.o. female patient with Sjögren syndrome comes to you and complains about not being able to “chew a cracker” and that she has “dirt in the eye” what would you tell her ?

A

well, DUH!

your eyes are dry (keratoconjunctivits sicca) and your mouth is dry (xerostomia)

67
Q

describe the pathogenesis in Sjögren syndrome

A

The pathogenesis of Sjögren syndrome remains obscure

it is beleived that the disease is initiated by loss of tolerance of autoreactive CD4+ T-cells

  • ANA
  • Anti-RNP Ab’s (Antibodies against ribunucleoprotein antigens)
  • Anti SSA
  • Anti SSB
  • RF
  • antibody reactive with self IgG
68
Q

what is the primary target of autoantibodies in Sjögren syndrome?

A

ductal epithelial cells of exocrine glands

69
Q

25% of patient with Sjögren syndrome develope…?

A

Extraglandular disease
(CNS, SKIN, KIDNEY, MUSCLES)

extraglandular manifestations include :

synovitis , pulmonary fibrosis , peripheral neuropathy

70
Q

presence of Sjögren syndrome increases X40 the risk for what disease ?

A

non-hodgkin B-cell lymphoma

71
Q

in Sjögren syndrome we observe enlargement or shrinkage of salivary glands ?

A

there’s Enlargement of salivary glands and particularly Unilateral enlargement of the parotid gland is seen
due to lymphatic infiltration

72
Q

what predisposes the development Anti-RNP Ab’s present in Sjögren syndrome?

A

inheritance of certain MHC 2 alleles

73
Q

Sjögren syndrome can be related with which other autoimmune disease ?

A

Rheumatoid arthritis

74
Q

Systemic Sclerosis(scleroderma) is an immunologic disorder charechterized by excessive …

A

**FIBROSIS in multiple organs

e.g.-**
skin, GI, kidney , heart , lung, skeletal muscle

75
Q

Systemic Sclerosis can be divided into …

A

2 types :

1) Diffuse Scleromderma
progressive,entire skin,early visceral involvement

2) Limited Scleroderma
slow progression, only skin of face & fingers , late visceral involvment,better prognosis

76
Q

Limited Scleroderma is Also Known AS…

A

the “CREST” syndrome

  • *C**alcinosis/anti Centromere antibodies
  • *R**aynaud phenomenon(vaso-spasm)
  • *E**sophageal dismotility
  • *S**clerodactyly (fibrosis in skin of fingers makes it tight ,shiny non-mimc face)
  • *T**elangiectasia (small dilated vessels in skin)
77
Q

during pathogenesis of systemic scleroderma , activation of mast cells and macrophages leads to …

A

release of (cytokines) IL-1, PDGF, TGFβ​ ,FGF that will activate fibroblasts and lead to excessive fibrosis

78
Q

The pathogenesis of Systemic sclerosis involves activation of B cells that leads to the generation of …

A

ANA - Anti Nuclear Antibodies against :

1) DNA Topoisomerase 1 in Diffused type
2) Anti Centromere Antibodies in Limited type

79
Q

ischemic injury is seen in systemic sclerosis. how cum dis ?

A

in Systemic Sclerosis there’s Microvascular disease in which endothelial damage and dysfunciton causes
Platelet aggregation–>PDGF–>Fibrosis–>narrowing of VASCULATUUUUUURE –>ischemia

80
Q

Which part of the GI is most affected in Systemic Sclerosis ?

A

the Esophagus is affected the most. due to dismotility and L.E.S dysfunction reflux occurs and Barret metaplasia can develope

81
Q

the microvascular disease present in systemic sclerosis is particulary dangerous in regarding of the lungs because …

A

pulmonary endothel dysfunction leads to hypertension and furthermore Cor Pulmonale Chronicum

82
Q

which arteries in the kidney thicken and cause hypertension in systemic sclerosis ?

A

Interlobular arteries

83
Q

whats the percentage of patients of systemic sclerosis that develope hypertension ?

A

30% of patients. out of which 20% develop malignant hypertension and die due to Renal failure

84
Q

what are the pathological manifestation that occur in the heart of patients with systemic scleroderma

A

Cardiac raynaud - endothel injury leads to fibrosis that causes thickening of the intramyocardial arterioles

85
Q

systemic sclerosis is more common in …

A

women ages of 50-60

86
Q

how can we differintiate Systemic Sclerosis from Rheumatoid arthritis and SLE ?

A

in Systemic sclerosis there’s diffused cutaneous involvement

87
Q

in ALL patients with Systemic Sclerosis we see …

A

Raynaud’s disease - causes areas such as fingers and toes to feel numb and cold in response to cold/stress.

In Raynaud’s disease, smaller arteries that supply blood to your skin narrow, limiting blood circulation to affected areas (vasospasm)

88
Q

Polyarteritis Nodosa belongs to which group of disorders ?

A
  • belongs to group of disorder characterized by necrotizing inflammation of the walls of any type of blood vessels
  • Not related to infections ,has Immunologic pathogenesis
89
Q

mention the 4 types of hypersensitivity reactions

A

“ACID”

type 1 - Allergic /IgE mediated, quick onset

type 2 - Cytotoxic

type 3 - Immune complex deposition/IgM,IgG mediated

type 4 - Delayed/cell mediated

90
Q

which type of hypersensitivty reaction is resembeled in sjorgen syndrome ?

A

type 4 , delayed , cell-mediated hypersensitivity reaction

91
Q

Primary immunodeficiencies what means dat ?

A

inherited genetic disorders that impair innate and humoral/cellular arms of the adaptive immunity

92
Q

name few primary immunodeficiencies

A
  • Severe Combined Immunodeficiency (SCID)
  • X-linked Agammaglobulinemia
  • common variable immunodeficiency
  • isolated IgA deficiency
  • Hyper IgM Syndrome
  • thymic hypoplasia(Di-george syndrome)
  • Wiskott aldrich syndrome
  • complement proteins deficiency
93
Q

describe X-linked Agammaglobulinemia

A

failure of pre-B cell to mature into B-cells due to a mutation in tyrosine kinase involved in the signal transduction of the process .

-light chains not produced.
-decreased B-cell number and absence of plasma cells
-reccurent bacterial infecitons
(obviously apears more in males because x-linked)

*intravenous ig’s are given

94
Q

common vairable immunodeficiency is charechterized (CVID) by …

A
  • group of disorders characterized by Low IgG due to B/Th cells defects
  • increased susceptibility to infections/lymphoma and impaired response to infections.
  • Same clinical features as in XLA except that sexes are equally affected and the late onset (2nd-3rd decade)

(unlike XLA normal number of B-cells BUT Absence of plasma cells)

95
Q

what is the most common primary autoimmune disease ?

A

isolated IgA deficiency in which serum/mucosal IgA levels are low due to a block in terminal differintiation of IgA secreting B-cells to plasma cells.

  • weak mucosal defenses predisposes patient to infections -especially viral.
  • seen in celiac’s disease
96
Q

Hyper IgM syndrome is charechterized by low IgG , IgA,IgE. why?

A

in normal cases IgM is produced first and then there’s “class switch” mediated by CD40L of Th cells to IgG,IgA,IgE

  • in Hyper IgM syndrome there’s a defect in CD40L of Th cells and they can’t activate B cells leading to an impaired “class switching”
  • less macrophage activity and less opsonization (low IgG) lead to higher risk for infections.
  • note thate IgM is produced in normal levels (supranormal)
97
Q

Di-george syndrome occurs due to …

A

-defect in 3rd/4th pharyngeal pouches
(thymus , PThy.G ,face ,Aortic arch )

-in 90% of cases- deletion of chromosome 22q11!!!

-thymus hypoplasia
leads to impaired T-cell maturaiton thus increased risk for infection by intracellular bacteria

  • parathyroid gland malformation
  • *hypocalcemia**
98
Q

SCID (severe combined immunodeficiency is a group of genetic syndromes characterized by …

A

-defects in humoral and cellular component of the immune system and **impaired development of T/B cells

-**
higher risk for fungal, viral ,bacterial,opportunistic, infections
——————————————————————————-
The most common forms of SCID:

-50% x-linked**

  • mutation in gene encoding common gamma chain of various cytokines especially IL-7 which is necessary for survival of immature T/B cells precursor

-40-50% autosomal recessive

  • ADA (adenosine deaminase-2nd most common) mutation results in impaired purine metabolism
  • ​impaired MHC2 expression
  • mutation in recombinase gene
    (involved in ig’s production)
99
Q

mention the clinical features of SCID

A

for both common gamma chain /// ADA mutations

  • Hypoplastic thymus
  • atrophic lymph nodes and lymphoid tissue
  • lymphopenia of T/B cells
100
Q

Wiskott-Aldrich syndrome is charechterized by a Triad of clinical features,namely ..

A

1) Thrombocytopenia
2) Eczema
3) Recurrent infections

  • defected gene located on X chromosome codes for Wiskott-Aldrich protein .
  • progressive (as you age) T cells depletion
  • ​no antibodies against LPS so can’t fight encapsulated bacteria (e.g. pyogenic)
101
Q

complement proteins deficiency is an example of genetic deficiency of …

A

the innate immune system .

examples :

  • C1 inhibitor - leads to HANO (hereditary angioedema)
  • edema especially in periorbial region
  • C5-8 deficiency -recurrent infection be Neisseria
  • C3 deficiency -increased risk for infection with pyogenic bacteria
  • C1q ,C2, C4 - risk for immune complex mediated disease e.g. SLE
102
Q

which defects in phagocytic activity can lead to deficiency of the innate immunity ?

A
  • defects in oxidase enzyme - chronic granulomatous disease
  • defect in integrins and selectin ligand- impaired adhesion of leukocyte
103
Q

Secondary immune deficiencies are …

A

Aquired. more common than primary (inherited) immune deficiencies.

mostly commonly seen in patients with therapy induced -suppression of bone marrow and lymphocye function

also seen in patients with -cancer,diabetes ,infection ,malnutrition,renal disease ,sarcoidosis

104
Q
A