Immunology Flashcards

1
Q

Cells of the immune system: granulocytes

A

BEN

  • Basophils- stain blue
  • Eosinophils- stain pink
  • Neutrophils
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2
Q

Cells of the immune system= antigen presenting cells

A
  • Dendritic cells
  • Monocytes- only found in the blood
  • Macrophages- stays in the tissue, does not circulate in the blood
  • B cells
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3
Q

Cells of the immune system= lymphocytes

A

25% of total WCC in peripheral blood

CD34+ HSCT in bone marrow

IL2 = T, B + NK growth factors

IL7 + IL15 = T + NK development

  • T cells (adaptive immune system)
  • B cells (adaptive immune system)
  • NK cells (innate immune system)
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4
Q

Cells of the immune system = phagocytes

A
  • Neutrophils, Monocytes, Macrophages
  • Receptors
    • Fc= Ig
    • C3b= complement
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5
Q

Function of dendritic cells

A
  • ONLY antigen presenting cell that activates NAIVE T cells + initiates an immune response
  • Critically important in vaccination
  • Short lifespan = 3 days
  • Single dendritic cell can present an antigen to several T cells
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6
Q

Immunodeficiency conditions resulting in: recurrent sinopulmoonary infection

A
  • Antibody production defects
    • CVID
    • X linked agammaglobulinaemia (XLA)
    • Transient hypogammaglobulinaemia of infancy
  • Complement protein deficiencies
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7
Q

Immunodeficiency conditions resulting in: broad infectious susceptibility + FTT

A
  • SCID
  • Wiskott Alrich
  • DiGeorge
  • Ataxia telangiectasia
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8
Q

What is the cause?

A

XLA: x-linked agammaglobulinaemia

Absent B cells + hypogammaglobulinaemia

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9
Q

CD3

A

T cell marker

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10
Q

CD19 + CD20

A

B cell marker

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11
Q

CD56

A

NK cell marker

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12
Q

CD4

A

Helper T cell marker

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13
Q

CD8

A

Cytotoxic T cell marker

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14
Q
A
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15
Q

Disorders of humoral immunity (B cell differentiation + antibody production)

  • Onset
  • Pattern of infection
  • Other features
A
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16
Q

X linked (Bruton’s) agammaglobulinaemia

  • KEY features
  • Gene + protein implicated
  • Clinical manifestations
  • Investigations
  • Management
A

Hypogammaglobulinaemia, NO circulating B cells, absent tonsils/lymph nodes

  • Gene + protein implicated
    • Xq22- XLA gene
    • Bruton tyrosine kinase deficiency = pre B cell arrest
    • Males 1:100 000- 1:200 000
  • Clinical manifestations
    • Well until ~ 6 months of age (maternal IgG antibodies protective until then)
    • Lymphoid hypoplasia
    • Recurrent infections with extracellular organisms (strep pneumonia, Haemophilus)
    • Viral infections usually handled except hepatitis + enterovirus
    • Paralysis with poliovirus
    • Chronic fungal infections
    • Types of infections: sinusitis, OM, pneumonia, sepsis, meningitis
    • Associated with rheumatoid arthritis, sarcoid
  • Investigations
    • Neutropenia at HEIGHT of infection
    • Peripheral blood B lymphocytes <1%
    • High T cell percentage, normal T cell subset ratios
    • Normal T cell function + thymus
    • LOW or absent immunoglobulins
    • Antibodies to vaccines absent
    • Intestinal biopsy= absence of plasma cells
    • Prenatal testing can be performed
  • Management
    • Lifelong IVIG (does NOT correct IgA deficieincy or prevent enterovirus)
    • Antibiotics
17
Q
A

D) Specific antibody responses to vaccine antigens should be assessed

18
Q

Criteria for common variable immunodeficiency (CVID)

A
19
Q

T cell dependent + independent vaccines

A
  • T cell dependent: isotype switched, high affinity, long lived plasma cells (IgA, IgG, IgE)
    • Protein vaccinations (Diptheria, tetanus, HiB, PCV)
  • T cell independent: mainly IgM, short lived plasma cells
    • Polysaccharide vaccinations (Pneumovax 23)
20
Q

What is the diagnosis?

A

Severe combined immunodeficiency

  • PJP + FTT + thrush
  • Anaemia + lymphopenia
  • Hypogammaglobulinaemia
  • Low CD3 (T cell marker) + CD56 (NK cell marker)
  • PHA (T cell mitogen response) = low
21
Q
A

X-linked Hyper IgM = T cell defect

22
Q
A

Chronic granulomatous disease

23
Q

What is recognised by the innate immune system?

A

PAMPS + DAMPS

24
Q

CD28

A

Co stimulatory molecule on T cells which binds to B7 on antigen presenting cells and causes proliferation + differentiation. If B7 on the APC not present then it will not cause activation of the T cell.

25
Q

CTLA4

A
  • Inhibitor of T cell activation. Binds to B7 on APC and inactivates it.
  • HIGHER affinity to B7 than CD28
26
Q
A