Immunology Flashcards by Jasmine Moore

What are the major hallmarks of immune deficiency?

SPUR
Serious infections
Persistent infections
Unusual infections
Recurrent infections

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What are the cells and proteins in the innate immune system?

Cells

Macrophages
Neutrophils
Mast cells
Natural Killer Cells

Proteins

Compliment
Acute Phase Proteins
Cytokines

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What are the cells and proteins in the acquired immune system?

Cells

B lymphocytes
T lymophocytes

Proteins
- Antibody

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What are the 3 functions of the innate immune system?

Rapid clearance of microorganisms
Stimulates the acquired immune response
Buys time while the acquired immune system is mobilized

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What are the main phagocytes?

Neutrophils

Monocyte/Macrophages

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What are the main functions of the phagocytes?

Initiates and amplifies the inflammatory response.
Scavenges cellular and infectious debris
Ingests + kills microorganisms
Produces inflammatory molecules that regulate other components of the immune system
Resolution and Repair

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What are Phagocytes most important in defence against?

Bacteria and Fungi

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What might reccurent infections tell you about a patient’s phagoctes?

There is a deficiency.

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What are the 4 types of organisms that may give rise to infection in a patient with phagocyte deficiencies?

Common - (Staph Aureus)
Unusual - (Burkholderia cepacia)
Mycobacteria - (TB and atypical mycobacteria)
Fungi - (Candida, Aspergillus)

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What is reticular dysgenesis?

Failure of stem cells to differentiate along myeloid lineage. (Failure to produce neutrophils)

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What are two specific conditions that lead to failure of neutrophil maturation?

Kostmann syndrome - (severe congenital neutropaenia)

Cyclic neutropaenia - (Episodic neutropaenia every 4-6 weeks)

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Does recticular dysgenesis allow for the production of T/B-Lymphocytes + Natural Killer Cells?

No.
Recticular dysgenesis halts productions before stem cells can become a common lymphoid progenitor OR a common myeloid progenitor.

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Does Kostmann syndrome allow for the production of Monocytes and Neutrophils?

NO.
Kostmann syndrome halts production of neutrophils. Howevrer sufferers can still create monocytes and all the lymphoid profenitor things (Lymphocytes and NKCs)

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What would be the classic clinical presentation of Kostmann Syndrome?

Reccurent bacterial infections
Systemic or localised infection
(WITHIN 2 WEEKS AFTER BIRTH)

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What definitive treatments could you give a child with Kostmann Syndrome?

Stem cell transplant

Granulocyte colony stimulating factor (G-CSF) - (specific growth factor to assist maturation of neutrophils

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What are the supportive treatments for Kostmann Syndrome?

Prophylactic antibiotics

Prophylactic antifungals

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What is the mortality % of children with Kostmann Syndrome in the first year without definitive treatment?

70%!

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What are upregulated in the blood supply at sites of infection to stimulate neutrophil adhesion and migration into tissues

Endothelial Adhesion Markers

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What is the condition when phagocytes are unable to identify Endothelial Adhesion Markers and what would happen?

Leukocyte adhesion deficiency.

failure of neutrophil adhesion and migration.

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Is Leukocyte adhesion deficient a primary or secondary immunodeficiency?

RARE primary. (From birth)

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What would be the clinical presentation of Leukocyte adhesion deficiency?

Marked leukocytosis

Localized bacterial infections that are difficult to detect.

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What is the difference between direct and indirect recognition of a Pathogen by a phagocyte?

Indirect uses opsonins which act as binding enhancers on the surface of the phagocyte.

Direct binds directly

Name the different types of opsonin.

Complement C3b, IgG antibody and C-reactive protein.

What could cause defective phagocytosis?

Defect in opsonin receptors.

Defect of complement or antibody production (decreased efficiency of opsonisation)

What is chronic granulomatous disease?

Failure of oxidative killing mechanisms.

What are the main causes of Chronic granulomatous disease?

Absent respiratory burst - Deficiency of intracellular killing mechanism of phagocytes - inability to generate oxygen free radicals - Impaired killing of intracellular micro-organisms Inability to clear organisms - Failure to degrade chemoattractants and antigens - persistant accumulation of neutrophils, activated macrophages and lymphocytes

What are the main clinical presentations of Chronic Granulomatous Disease?

``` Recurrent deep bacterial infections - (Staphylococcus, Aspergillus, Pseudomonas capacia. Mycobacteria, atypical mycobacteria) Recurrent fungal infections Failure to thrive Lymphadenopathy + hepatosplenomegaly Granuloma formation ```

What is the investigation of choice for chronic granulomatous disease?

Nitroblue Tetrazolium test (NBT) (feed patient neutrophils source of Ecoli Add dye sensitive to H2O2 if H2O2 is roduced by neutrophils, dye changes colour)

What are the supportive and definitive treatments of chronic granulomatous disease?

``` Supportive - prophylactic antibiotics + antifungals Definative - Stem cell transplantation - Gene therapy ```

What is the problem with intracellular organisms?

They hide from the immune system by locating within cells. (e.g. Salmonella, Chlamydia, Rickettsia) Some hide in immune cells! (e.g. Mycobacteria)

What does an infection with mycobacteria (TB) lead to to allow the body to fight it when the mycobacteria is within a macrophage?

Activates IL12 - gIFN network Interleukin12 (IL12) is released by infected macrophage. IL12 induces T cells to secrete gamma interferon (gIFN) gIFN feeds back to macrophages + neutrophils Stimulates TNF production Activates NADPH oxidase Stimulates oxidative pathways.

What would a defect in the IL12 - gIFN axis cause?

Patient with sucseptability to intracellular bacteria | e.g. Mycobacteria + Salmonella

Why are anti-TNF drugs, used in the treatment of inflammatory diseases sometimes contraindictive?

Can lead to reactivation of latent Tuberculosis! | MIND = BLOWN

What investigation would allow you to check the mobilisation of phagocytes from bone marrow?

FBC

What investigation would you use to check oxidative killing?

NBT

What would be the aggressive management of an infection in a patient with phagocyte deficiency?

Infection prophylaxis Oral/intravenous antibiotics Surgical draining of abscesses

What is the definitive treatment for a patient with phagocyte deficiency?

Bone marrow transplantation | Specific treatment for Chronic granulomatous disease - (e.g. gIFN therapy)

At what stage does the acquired immune system begin to respond to infection?

> 96 hours after innate begins.

Where do pre-T cells originate?

They arise from haematopoetic stem cells in bone marrow.

What happens to pre-T cells in the Thymus?

Maturation and selection takes place. | 10% of cells survive and enter the circulation and reside in lymph nodes and secondare ymphoid follicles.

What do CD4+ T lymphocytes do?

Provide costimulatory signals - (activate CD8+ T lymphocytes and naive B cells) Produce cytokines Regulate other lymphocytes and phagocytes. Recognise peptides on HLA Class II molecules.

What do CD8+ T lymphocytes do?

Recognise peptides in association HLA Class I. Directly kills cells - (Produces pore-forming perforin, triggers apoptosis of the target, Secrete cytokines (e.g. IFNy)) Important in defence against viral infections and tumours.

Where do B lymphocytes arise from?

Haemopoetic stem cells in bone marrow

Where would you find mature B lymphocytes?

Bone marrow lymphoid tissue spleen

What is severe combined immunodeficiency?

Failure to produce lymphocytes.

How would a patient present with severe combined immunodeficiency?

``` Unwell by 3 months persistent diarrhoea failure to thrive infections of all types (SPUR) skin diseases Family history of early infant death. ```

Why do children with severe combined immunodeficiency not usually present before 3 months?

Because the maternal IgG protects them in the first 3 months of life but their immune system has not matured enough to fight infections.

What would you expect the levels of T cells, B cells and lymphoid tissue to be like in a child with SCID?

Very low or absent T cells Normal or increased B cells Poorly developed lymphoid tissue + thymus

What is DiGeorge syndrome?

Developmental defect of the 3rd/4th pharyngeal pouch.

What would you expect in a child with DiGeorge syndrome?

Fucked from the ears to the heart. NO T cell maturation site

what levels of cells would you see in DiGeorge syndrome?

Absent or decreased number of T cells Normal or increased B cells (Low IgG, IgA, IgE) Normal NK cells

What would be a consequence of Bruton's X-linked hypogammaglobulinaemia? (Failure to produce mature B cells)

No circulating B cells No plasma cells No circulating antibody after first 6 months

What is common variable immune deficiency?

A problem with IgM B cells differentiating causing low IgG, IgA, and IgE

why am i doing this?!

Coz it's shite.