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Haem/Immunity > Haem/Imunity > Flashcards

Haem/Imunity Flashcards

1
Q

Protein that transfers iron through the blood

A

Transferrin

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2
Q

If transferrin is high, and ferretin is normal:

A

Suggests iron deficiency
Ferretin is an “acute phase reactant” - ie may have low ferretin, but infection/ inflamation etc is driving level up artificially

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3
Q

If transferrin is high, and ferretin is normal:

A

Suggests iron deficiency
Ferretin is an “acute phase reactant” - ie may have low ferretin, but infection/ inflamation etc is driving level up artificially

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4
Q

Types of Thalassemia

A

Alpha and Beta - in regards to body’s genetic inability to create associated globin chains

4 alpha genes - deletion of 1 gene generally asymptomatic, 2 moderate, deletion of 3 is severe anaemia, deletion of 4 alpha genes is incompatable with life

2 beta genes - minor to major anaemia, requiring no - frequent infusions

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5
Q

Most common type of hereditary haemochromatosis

A
  • Hereditary Haemochromatosis type 1
  • HFE gene related
  • Excessve intestinal absorption of dietary iron
  • Most common Northern European descent - especially Celtic
  • Excessive expression of DMT1 (Divalent Metal Transporter 1) - Which is the major iron transporter that contributes non-heme iron uptake in most types of cell.
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5
Q

Hemachromatosis inheritance traits and management for men and women

A

Autosomal recessive
Women generally do not need venesection due to menstrual blood loss until menopause

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6
Q

How is Hemachromatosis heritable?

A

Autosomal recessive
Women generally do not need venesection due to menstrual blood loss until menopause

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7
Q

Summarise development of aquired immune response to an antigen (flowchart Dr Raj)

A
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8
Q

Key physical exam check for thrombocytopaenia

A

Thrombocytopaenia - Abnormally low levels of platelets (thrombocytes)

Mucosal membranes for bleeding/petecchia
Statistically significant correlation for intracerebral haemorrhage

More important than “dependent” areas - gravity dependent such as ankles, legs, etc

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9
Q

Primary vs Secondary Neutropenia

A

Neutropenia = Abnormally low Neutrophils

Primary autoimmune neutropenia (AIN) -
When seen in infancy:
- Neutropenia is the sole abnormality
- Rarely associated with serious infections and exhibits a self-limited course.

Chronic idiopathic neutropenia of adults is characterized by occurrence in late childhood or adulthood

Secondary AIN
More commonly seen in adults
Underlying causes include:
- Collagen disorders
- Drugs
- Viruses
- Lymphoproliferative disorders.

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10
Q

Common presenting symptoms of severe neutropenia

A
  • Low-grade fever
  • Sore mouth
  • Odynophagia - pain swallowing
  • Gingival pain and swelling
  • Skin abscesses
  • Recurrent sinusitis and otitis
  • Symptoms of pneumonia (eg, cough, dyspnoea)
  • Perirectal pain and irritation
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11
Q

Patients with agranulocytosis usually present with the following:

A

Agranulocytosis - Insufficient granulocytes (Neutrophils, Basophils, Eosinophils, Mast cells)

May be asymptomatic for a time, but when patients present they have:

  • Sudden onset of malaise
  • Sudden onset of fever, possibly with chills, sweats and prostration
  • Stomatitis and periodontitis accompanied by pain
  • Pharyngitis, with difficulty swallowing
  • Lung infections are usually bacterial or fungal pneumonias
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12
Q

Physical findings on examination of a patient with neutropenia may include the following:

A
  • Fever
  • Stomatitis
  • Periodontal infection
  • Cervical lymphadenopathy
  • Skin infection: Rashes, ulcers, or abscesses
  • Splenomegaly; Associated petechial bleeding;
  • Peri-rectal infection
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13
Q

Anaphylaxis 2nd line therapies
(AFTER ADRENALINE/EPINEPHRINE)

A
  • Corticosteroids -have a delayed effect (4–6 hours), generally used to reduce duration of reaction & prevent relapse (should not be used instead of adrenaline)
  • Antihistamines- used as adjuncts helpful for associated urticaria, angioedema & itch.
    – including H-2 blockers e.g. Ranitidine if H-1 blockers ineffective
  • Beta2 agonists -Inhaled (via MDI and spacer) or nebulised short-acting beta2 agonists may help relieve bronchospasm that is resistant to adrenaline.
  • Glucagon - if still hypotensive in spite of fluids & adrenaline, give Glucagon IV – which exerts positive inotropic & chronotropic effects by directly activating adenylyl cyclase & bypassing β-adrenergic receptor
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14
Q

Corticosteroid effects on immune response - especially in anaphylaxis

A

Antiinflammatory - reduce production of many cytokines such as IL-4,5,17, TNF-a

Immune suppressant - to avoid continuous presence of anaphylactic reaction after allergen removed

Doesn’t work as quickly as epinephrine -

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15
Q

Histamine receptors and actions

A
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16
Q

What is central tolerance?

A

Central tolerance occurs in the Thymus (T cells) or the Bone marrow (B cells) and removes lymphocytes that respond too strongly to self antigens

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17
Q

What is peripheral tolerance?

A

Peripheral tolerance further regulates the immune response and protects the body from any lymphocytes that do respond to self but have made it into the circulation

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18
Q

What are the mechanisms of autoimmunity?

A

1- Reversal of anergy
- Failure to inhibit peripherally autoreactive T-cell clones

2- Local tissue damage
- Can release intracellular antigens
- Can expose new antigens arising from self proteins perviously unseen by immune system

3- Alteration of self-antigens
- Alteration of shape of self protein - ie citrulination in RA
- Infectious organisms alter self antigens - ie viral infection proceeds pancreatic B-cell autoimmunity in T1DM

4- Hypersensitivity reactions
- Autoimmune diseases may result in hypersensitivity reactions - RA, SLE

5- Molecular mimicry
- T-cells activated by infectious agents with structural similarities to self-proteins
- T cells then re-activated due to only exposure of self peptide with MHC complex

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19
Q

What is Anergy?

A

Mechanism of inactivating peripheral self reactive T-cell clones

Anergy occurs through disruption of signals, failure to express co- stimulatory signals or inhibition of the activation signal

Reversal of anergy can lead to autoimmune disease

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20
Q

Most common cause of severe malaria and survival rates

A

Plasmodium Falciparum
Mortality is 10-20% despite optimal Rx
Nearly 100% without treatment
Mortality in pregnant women 2 & 3 trimester ~ 50%

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21
Q

Diagnosis of malaria

A
  • Microscopic analysis of thick and thin films (3) - gold standard
  • Rapid Diagnositc Test - remain positive for 1 month after infection
  • PCR - most accurate, research test only
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22
Q

What is the most effective antimalarial

A
  • IV Artesunate - short half life, reaches peak concentration in ~10 minutes
  • Parasite clearance with Artesunate typically occurs within 72 hours.
  • Should be documented with thick and thin blood smears every 12 hours
  • After 24 hours can commence oral medications
  • Kills young circulating ring staged parasites which quinine does not
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23
Q

Specific Rx consideration for Plasmodium Vivax and Ovale infections

A

Primaquine or Tafenoquine - Kills early stage oocytes
- These subtypes can lay dormant in hepatocytes and pop up years later without further exposure

Primaquine also given to Falciparum infections in Northern Australia - prevent acute onspreading

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24
Q

MOA of LMWH (low molecular weight heparin)

Examples too

A

Inhibits factor Xa

Enoxaparin (Clexane), Dalteparin

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25
Q

MOA of Heparin

A

Inhibits
XIIa
XIa
IXa
(mostly intrinsic pathway)

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26
Q

What the hell is a NOAC?

A

Newer Oral AntiCoagulants (aka DOAC - direct-acting oral anticoagulants, as they are actually >15yo)

  • Direct thrombin inhibitor (dabigatran)
  • Factor Xa inhibitors (apixaban and rivaroxaban)
  • For most indications, one or all three have been demonstrated in clinical trials to be as effective as warfarin
  • Fewer drug and food interactions than warfarin

According to Judy, Don’t need monitoring

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27
Q

Measurement of PT vs aPTT

A

PT ~ Extrinsic Pathway - Unique factor VIIa

aPTT ~ Intrinsic Pathway - Unique factor VIIIa

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28
Q

Risk factors associated with VTE

A

Venous ThromboEmbolism

– Older age
– Immobility
– Malignancy
– Obesity
– Previous VTE
– Family history of VTE
– Oral contraceptive pill, hormone replacement, tamoxifen, strontium (Protos™ - for osteoporosis)
– Venous insufficiency/varicose veins

Hip or Knee replacement!

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29
Q

Measures for VTE prophylaxis

A

Venous ThromboEmbolism Prophylaxis

  • Anticoagulants (injections and/or oral)
  • Graduated compression stockings (GCS)
  • Intermittent pneumatic compression (IPC)
    • Inflatable pneumatic pump provides intermittent cycles of compressed air, enhancing venous return
  • Pneumatic foot compression or pump
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30
Q

What is Atopy?

A

The genetic tendency to develop classic allergic diseases - atopic dermatitis, allergic rhinitis (hay fever) and asthma

Atopy involves the capacity to prroduce IgE in response to common environmental proteins

From Greek - “atopos” - out of place

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31
Q

Define Allergy

A

A misguided reaction to foreign substances by the immune system

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32
Q

Describe the “Normal” inflammatory response

A

Vascular Events
- Initial vasodilator response
- Increase in capillary permeability - leakage of plasma proteins (antibodies, complement, clotting factors)
- Increase in extravascular protein content -> accumulation of interstitial fluid
- Increased blood viscocity due to leakage of fluid -> slow blood flow through vessels -> increase contact of white blood cells with vessel endothelium

Cellular Events
- White blood cells adhere to endothelium - due to slower flow
- WBCs respond to chemotactic factors -> diapedesis - migrate into interstitial space

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33
Q

Activation of the complement cascade causes which main effects

A

A. Opsonisation of bacteria
B. Release of factors that are chemotactic for phagocytes
C. Release of factors that activate phagocytes and other white cells
D. Lysis of bacterial cells

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34
Q

How do phagocytes know what to digest?

A

By recognising:

Pathogen-associated molecular patterns (PAMPs)
- Carbohydrates or lipopolysaccharides in the bacterial cell wall, bacterial DNA or viral RNA

Complement surrounding bacteria (opsonisation)
- C3b receptors on the phagocyte recognise C3b surrounding the bacteria

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35
Q

What are the two classes of MHC and where are they present?

A

Major Histocompatability complex

MHC class I
- Present on virtually every cell in the body
- Marker of self that the body recognizes
- Cytotoxic T cells recognize MHC class 1 in combination with foreign antigen

MHC class II
- Appear mainly on macrophages and B cells, helper T cells

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36
Q

Describe the structure of an antibody molecule
- Light chain
- Heavy chain
- Fc
- Fab

A
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37
Q

Summarise major immunoglobulin classes in humans

A
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38
Q

Functions of antibodies in the acquired immune response

A
  • Activate B lymphocytes
  • Act as opsonins
  • Cause antigen clumping and inactivation of bacterial toxins
  • Activate antibody-dependent cellular activity (NK cell and eosinophils)
  • Trigger mast cell degranulation
  • Activate complement
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39
Q

MOA of LMWH and Fondaparinux

A

Factor Xa Inhibitor

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40
Q

Summarise Oral Anticoagulants and their main targets

A
  • Direct thrombin inhibitor
  • Dabigatran (Pradaxa)
  • Direct factor Xa inhibitors
  • Apixaban (Eliquis)
  • Rivaroxaban (Xarelto)
  • Vitamin K antagonist
  • Warfarin (coumadin, marevan)
41
Q

Summarise pros and cons of warfarin

A
  • Vit k antagonist (reversible)
  • Oral medication (easy at home)
  • Low therapeutic index (requires regular monitoring)
  • Teratogenic
  • Metabolised by cytochrome P 450 in liver (many drug interractions due to common metabolism pathway)
42
Q

3 most common indications for warfarin therapy

A
  • Atrial Fibrilation (AF)
  • Venous thromboembolism (VTE)
  • Prosthetic heart valves
43
Q

General target INR for warfarin

A

INR of 2-3.5 depending on clinical indication and other risk factors - can be different given patients coorbidities and requirements

At least 5 days required to achieve therapeutic INR

More regular INR monitoring is required at initiation of therapy

44
Q

Drugs that may have a potentiation effect on warfarin (increase effect)

A
  • Inhibitors of hepatic drug metabolism
    - Amiodarone, several antibiotics & antifungals
  • Drugs with antiplatelet effect
    - NSAIDs, Aspirin
  • Drugs that displace warfarin from binding sites on plasma proteins
    - NSAIDs
45
Q

Plasma is composed of:

A
  • Water
  • Ions
  • Trace elements and vitamins
  • Gases - O2, CO2
  • Organic molecules (such as)
    • Glucose
    • Lipids
    • Nitrogenous Waste
    • Amino acids
    • Proteins (such as)
      • Albumins
      • Globulins
      • Fibrinogen
46
Q

General summary of what mast cells release
(3 key factors, and their general effects)

A

Histamine, Prostaglandins, Leukotrienes

  • Vasodilation
  • Increase capillary permeability
  • Bronchial constriction
  • Neutrophil and Eosinophilic chemotaxis
47
Q

People with allergies/atopy have much higher serum levels of what immunoglobulin?

A

IgE

48
Q

How does IgE facilitate mast cell degranulation?
(picture)

A
49
Q

Which cell is largely responsible for late stage allergic response?

A

Eosinophils
- Associated with long term tissue damage from chronic allergic reactions
- They release:
- Reactive oxygen species
- Cytokines
- Growth fators
All contribute to tissue damage in chronic allergic reactions

  • Also elicit chronic T helper 2 cells in maintaining inflammation
50
Q

Which cell is secondarily responsible for late stage allergic reactions?

A

T helper 2 cells
- Attracted by Eotaxin along with eosinophils
- Once recruited, release:
- IL-4 which increases IgE synthesis
- IL-5 - chemotactic for eosinophils

Basically, they keep the ball rolling, compounding damage

51
Q

A hypersensitivity reaction can be defined as an immune response that is
———————- or is —————————

A

A hypersensitivity reaction can be defined as an immune response that is inappropriate because it is directed at a self antigen (i.e. autoimmunity) or is directed at an antigen that poses no significant risk to the body (e.g. pollen or transfused blood cells)

52
Q

Summary of 4 types of hypersensitivity reactions, and an example of each

A
53
Q

Major functions of the Innate Immune System are:

A
  • Physical and chemical barrier
  • Recruit immune cells to infection sites via chemotaxis
  • Activate complement cascade - opsonisation and MAC
  • Identify and remove foreign substances via WBCs
  • Activate adaptive immune system via antigen presentation
54
Q

Short summary of Type-4 hypersensitivity

A

T-Cell activation of the immune response following recognition of an antigen.
More than likely occurs after prior exposures, which sensitise people to subsequent exposures.

54
Q

What are the 2 major types of ingredients in vaccines?

A

Antigens
Can contain:
- Killed whole pathogen - killed by heat/chemicals (Hep A, polio)
- Components of pathogen
- Genetic engineering (Hep B, Human papiloma virus)
- Purifying from whole bacterium/virus
- Derivative of toxin produced by pathogen - harmless toxoid (tetanus, diptheria)

Adjuvants
- Amplify immune response - aluminium hydroxide widely used

55
Q

Cell precursors of erythrocytes

A
56
Q

What are some factors that decrease tissue oxygenation, and what does the body do as a result of this?

A
  1. Low blood volume
  2. Anaemia
  3. Low Hb
  4. Poor blood flow
  5. Pulmonary disease

Results in Erythropoiesis

57
Q

What is “Secondary Polycythemia”?

A

Secondary Polycythemia is a physiological condition:
An over production of Erythrocytes!

At high altitude or under other conditions that result in poor tissue oxygenation, secondary polycythemia may develop.

As opposed to polycythemia vera which is a pathological defect in regulation of erythropoiesis - resulting in higher RBC count

58
Q

IgM and IgG
Primary vs Secondary Response

A
59
Q

Sickle cell disease is a genetic defect in which ———-, the 6th out of 146 amino acid chain for ——— haemoglobin is replaced by ———

A

Sickle cell disease is a genetic defect in which Glutamate, the 6th out of 146 amino acid chain for Beta haemoglobin is replaced by Valine

Glutamic acid - hydrophilic
Valine - hydrophobic

Hence, lack of polarity here changes the shape of the protein and thus shape of RBC

60
Q

What is Granulation Tissue?

A

Granulation tissue is formed as the last stage of the inflammatory response.

Granulation tissue replaces the tissue that has undergone necrosis as part of the inflammatory response with connective tissue which makes up the scar.

61
Q

Summary of the steps in the activation of
the acquired immune response

A
  1. Macrophage/ APC engulfs bacteria and presents antigen
  2. Helper T cell activated by macrophage/ APC with a MHC complex
  3. B cell bind antigen and receives a cytokine signal from T helper cell
    (Or recognition of foreign antigen by naïve circulating B cells can autoactivate (T-independent))
  4. B cells undergo clonal expansion and differentiation, affinity maturation
  5. B cell matures into antibody secreting plasma cells
  6. Memory B cells remain behind once the infection is cleared. If the
    body is re-exposed to the antigen, the memory cells will recognize the antigen and respond quickly
62
Q

What are the intermediate steps from
Haematopoetic stem cell - Specialised Blood Cells

A
63
Q

What is Myeloid?

A

Having to do with the bone marrow, or certain types of haematopoietic cells found in bone marrow

64
Q

4 types of Leukaemia

A
65
Q

What is Multiple Myeloma?

A

“Multiple Myeloma represents a malignant proliferation of plasma cells derived from a single clone”

Ie - we end up with excessive plasma B cells accumulating in the bone marrow, and producing excessive amounts of antibody proteins

65
Q

How does Polycythaemia Vera (PV) start?

A

PV is a clonal stem cell disorder in which there is an alteration in the pluripotent progenitor cell leading to excessive proliferation of erythroid, myeloid and megakaryocytic progenitor cells

66
Q

What is Polycythaemia (Rubra) Vera?

A
  • A disorder where too many red cells are produced in the bone marrow, without any identifiable cause.
  • These cells accumulate in the bone marrow and in the blood stream
  • Cause increase in blood volume and viscocity
  • In many people with polycythaemia vera, excess platelets and white cells are also produced
67
Q

What is “Urticaria?”

A

Urticaria is also known as “hives” and is characterized by itchy, raised, swollen areas on the skin or mucous membranes, often a manifestation of an allergic reaction.

68
Q

How are the different antigens formed in the ABO blood group model?
What antibodies are formed as a result of this?

A

A - N-acetylgalactosamine (NAGA) is added
B - Galactose is added
AB - Both!
O - Neither!

Naturally occurring IgM anti-A and anti-B antibodies are called isoagglutinins or isohaemagglutinins

O forms antibodies against both
AB against neither

69
Q

What is VEGF

A

Vascular Endothelial Growth Factor
- Key factor for angiogenesis as the name suggests

Increases:
- Migration of endothelial cells
- Matrix metalloproteinase activity - break down connective tissue scaffolding
- Mitosis of endothelial cells

70
Q

How are MMPs relevant to neoplastic outcomes?

A

MMP = Matrix Metallo Proteinases

Increased expression of MMPs in human malignant tissue are often correlating with poor prognosis

They break down connective tissue scaffolding

71
Q

Difference on smear seen in ALL vs AML

A

Remember:
Acute Myeloblastic Leukaemia
Acute Lymphoblastic Leukaemia

AML: Myeloblasts are larger with more cytoplasm and Irregular Shaped Nuclei

Commonly have Auer Rods

Myeloid - more prominent nuclei

ALL: Smaller with Scant Cytoplasm

72
Q

3 most common types of Myeloproliferative neoplasms (MPNs)
Some key driver mutations too (pie graph)

A
  • Polycythemia Vera (PV)
  • Essential Thrombocythemia (ET)
  • Primary Myelofibrosis (PMF)

Classic DRIVER mutations are -
JAK -26V1F - Gene on chromosome 9
CALR exon 9
MPL exon 10

NOTE. -Not a strict category though, this is a SPECTRUM of disease and category!

TREATMENT often W TYROSINE KINEASE INHIBITORS

72
Q

Sites of Hematopoiesis age changes graph

A
73
Q

Summary of the coagulation cascade

A
74
Q

Self antigens associated with autoimmunity include:

A
75
Q

Symptoms and signs of Leukaemia

A
  • Asymptomatic
  • Anaemia
  • Neutropaenia - fever, infections
  • Thrombocytopaenia - Petechia (pinpoint like haemorrhages) , Purpura (bruising)
  • Bone Pain
  • Splenomegaly
  • Hepatomegaly
  • Lymphadenopathy
  • Testicular enlargement
  • Gum infiltration
  • Skin deposits
  • CNS involvement
76
Q

Diagnosis of Leukaemia involves:

A
  • Full blood count - FBC
  • Stain blood sample/ blood smear - microscope view
  • Bone marrow biopsy - Commonly around PSIS
  • Bone marrow Trephine biopsy - ratio cells:fat
  • Surface antigen expression
77
Q

Basic requirements for Graft Versus Host Disease (GVHD)

A
  • Graft must contain immune competent cells - relevant for TAGVHD (Transfusion Associated Graft Vs Host Disease)
  • Host must have antigens lacking in the graft so the host appears foreign to graft - lacking in syngenergic transplant (identical twin graft)
  • Host must be incapable of mounting an immune response against the graft - hence need for conditioning

Note - you can still get GVHD with a perfectly matched sibling donor and aggressive immunosuppressive therapy.

It’s a balancing act, as if there is no T-lymphocyte action against the host, there will be a relapse of leukaemia, and too my action against the host is GVHD

78
Q

Summarise Major Histocompatability Complex (MHC)

A
  • Cell surface glycoproteins
  • Highly variable between individuals

Class 1
- HLA-A, HLA-B, HLA-C
- Expressed on virtually all nucleated cells
- Present antigens to CD8+ cytotoxic/suppressor cells

Class 2
- HLA-DQ and HLA-DRB1
- Restricted to cells of the immune system (B-cells and monocytes)
- Molecules on macrophages that present antigenic fragments to CD4+ T-helper cells

79
Q

Types of Graft Versus Host Disease (GVHD)

A

Acute < 100 days
Usually at time of engraftment
Skin, GIT - malabsorption, diarrhoea, Liver (abnormal LFTs)

Chronic > 100 days
Skin
Liver
Lung and other tissues

80
Q

Describe Delayed Haemolytic Transfusion Reaction
(DHTR)

A
  • Haemolysis is more mild than severe AHTR (acute haemolyric transfusion reaction)
  • Patient may make a red cell antibody to a red cell antigen they lack after transfusion, transplantation or pregnancy
  • May be reaction between recipient antibodies and Rh (anti D) or minor Rh group antigens (C,E,c,e) - or non ABO antigens (Kidd, Duffy, Kell, MNS antigen system)

Symptoms
- Fever, declining Hb, mild jaundice - occuring days to weeks after transfusion

80
Q

What is the most common cause of transfusion related death in developed countries?

A

Transfusion Related Acute Lung Injury - (TRALI)

  • Resp distress disproportionate to volume of blood
  • Fever, chills, dyspnoea, tachypnoea, cyanosis, hypotension and new onset pulmonary oedema (non cadriogenic)- leading to resp failure within 6 hours of transfusion
  • Hypotension - helps distinguish from Transfusion Associated Circulatory Overload (TACO)

All products that contain plasma can cause this
Often underreported in minor cases - must inform lab though as these donors should be excluded from becoming future donors

Pathogenesis not exactly understood, but involves reaction activation of neutrophils in pulmonary microcirculation, releasing oxidases and proteases that damage vessels - leaky vessels

80
Q

Describe Transfusion - Related Circulatory Overload (TACO)

A
  • Potentially lethal volume overload
  • Due to rapid or massive transfusion, or too much fluid
  • Even a single unit can precipitate TACO in cardiac compromised patients
  • Avoid by administering components slowly (over 2-3 hrs)

Signs and symtoms
- Dyspnoea
- Orthopnoea
- Tachycardia
- Hypoxia
- Increased BP - helps theoretically distinguish from TRALI (Transfusion Related Acute Lung Injury)

Individuals at increased risk include:
- Diminished cardiac reserve
- Very young or very old
- Chronic anaemia
- Renal impairment

80
Q

Summary of 5 Immunoglobulins table

A
81
Q

Summary of heavy vs light chain locations in antibodies/immunoglobulins

A
82
Q

Summary of α-thalassemias

A
  • The α-thalassemias involve genes HBA1 & HBA2
  • Autosomal recessive
  • Two genetic loci exist for α-globin, thus four alleles are in diploid cells. Two maternal and two paternal alleles.
  • Severity is correlated with number of affected α-globin
  • Alpha-thalassemias -> decreased alpha-globin production -> fewer alpha-globin chains are produced, resulting in an excess of β chains in adults and excess γ chains in newborns.
  • The excess β chains form unstable tetramers (called hemoglobin H or HbH of 4 beta chains), which have abnormal oxygen dissociation curves.
  • Alpha thalassemias often are found in people from Southeast Asia, the Middle East, China, and in those of African descent.
83
Q

Summary of β thalassemia

A
  • β thalassemias are due to HBB gene on chromosome 11 mutaations
  • Autosomal recessive inheritance
  • Severity of disease depends on nature of mutation and presence of mutations in one or both alleles
  • Mutated alleles are called β+ when partial function is conserved (either the protein has a reduced function, or it functions normally but is produced in reduced quantity) or βo, when no functioning protein is produced.
  • β thalassemia major (Mediterranean anemia or Cooley anemia) is caused by a βo/βo genotype. No functional β chains are produced, and thus no hemoglobin A can be assembled. This is the most severe form of β-thalassemia;
  • β thalassemia intermedia is caused by a β+/βo or β+ β+ genotype. In this form, some hemoglobin A is produced;
  • β thalassemia minor is caused by a β/βo or β/β+ genotype. Only one of the two β globin alleles contains a mutation, so β chain production is not terribly compromised and patients may be relatively asymptomatic.
  • Most often in people of Mediterranean origin
84
Q

How is peripheral tolerance maintained?

ISADS

A

1. Ignorance – antigen is invisible to the immune system
2. Separation – antigen is isolated from the naïve immune cells
3. Anergy – self-reactive cells are deleted or inhibited
4. Deletion – activation leads to apoptosis
5. Suppression – Tregs inhibit the activity of self-reactive T cells

85
Q

Mnemonic for general DDx hypothesis

A

VINDICATE
(Covers literally everything that could go wrong anywhere - maybe not every letter useful in each case, but something to think about)

  • Vascular
  • Infection, Inflammation
  • Neoplasms
  • Drugs (also toxins), Degenerative
  • Iatrogenic, Idiopathic
  • Congenital (inherited, developmental)
  • Autoimmune, Allergy, Anatomical
  • Trauma
  • Endocrine (metabolic), Environment (work, exposure)
86
Q

Describe the process of non-neoplastic lymphadenopathy

A
  • Generally due to inflammatory stimuli caused by cellular proliferation
  • B-cell response (germinal cell hyperplasia) - Clonal expansion!
  • T-cell response (paracortical expansion)
  • Macrophage response (sinus hyperplasia)
  • Most commonly all of the above - B cell major player, making antibodies that work in the node and will spread throughout the system
87
Q

Describe neoplastic lymphadenopathy

A

Tumor secrets factors that promote lymphangiogenesis (along with angiogenesis)
Increases collection from the area, and makes it easier for metastisis to spread through the lymph system

88
Q

What are Auer Rods on a blood film associated with?

A

Acute Myeloid Leukaemia

89
Q

What are smudge cells on a blood film associated with?

A

Chronic Lymphocytic Leukaemia

  • Smudge cells are not actually a cell type, but an artefact from preparing the slides - ie cells get smooshed due to poor cell membrane and being larger than normal
90
Q

What do Reed-Sternberg cells on a lymph node biopsy indicate?

A

Hodgkin Lymphoma

  • Large lymphocyte with “owl eyes”
91
Q

Describe Ann Arbor Staging in Lymphoma

A
  • I - Localised disease: one group of lymph nodes affected
  • II - Two or more groups of lymph nodes are affected but they are all in the chest or abdomen
  • III - Two or more groups of lymph nodes are affected in both the chest and the abdomen with or without involvement of a nearby organ
  • IV - Widespread disease: lymphoma is in multiple organs or tissues (eg, bone marrow, liver or lungs) and may also be in the lymph nodes
92
Q

Describe - Induction, Consolidation and Maintenence therapy for leukaemia

A
  • Induction - To induce remission
  • Consolidation - Get rid of any MRD and prevent recurrence
  • Maintenence - Low dose chemotherapy for months or yearts post remission - prevent recurrence
93
Q

Quick summary of 4 types of Leukaemia

A

Lymphoids are Lateral
Myeloids are Medial
A’s First (Acute = immature blast cells >20%)
C’s Second
Listed in increasing age to be commonly diagnosed

94
Q

Summary of Methotrexate and its MOA

A

Methotrexate

Used as a:
- DMARD (Disease Modifying Anti-Rheumatic Drug) - RA, IBD, SLE, Eczema, and others
- Chemotherapy - ALL, Non-Hodgkin’s lymphoma, breast, bladder

MOA
- Inhibits the body’s use of folic acid which leads to->
- Interference with DNA replication - thus as a chemotherapy drug it targets quickly reproducing cells

95
Q

Summary of lymphatic drainage and return to the venous circulation

A

Haem/Immunity (1 decks)

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