Immunodeficiency Flashcards
What is Immunodeficiency?
Failure of all or a part of immune function
What are the different type of causes for immunodeficiency?
- Cancer/cancer treatment
- Genetics
- Ageing
- Injury
- Viral infection
- Autoimmune condition
- Malnutrition
- Medication
What is Primary Immunodeficiency (PIDs)
- Caused from genetic error
- Discovered in childhood
What is Secondary Immunodeficiencies (SIDs)?
- Gained through life
What is common between PID and SID?
Increased susceptibility to infection
What is combined deficiencies?
Affect both B and T cells
Where are Intrgrins found?
Surface of leukocytes
What occurs in humoral immunity to secrete antibodies?
1) Free antigens directly activates B cells
2) B cells then give rise to Plasma cells
3) Plasma cells then secrete antibodies
What regulates B cells in the humoral immunity?
Helper T cell
What is the role of Memory B cells?
To stimulate plasma b cells to produce antibodies against the 2nd antigen exposure
What is the role of antibodies in humoral immunity?
Defend against extracellular pathogens by binding to antigens to be targeted by phagocytes and complement
What happens in cell mediated immunity for active cytotoxic T cells to be secreted?
1) Antigens displayed by infected cells activate cytotoxic T cells
2) Cytotoxic T cell give rise to active cytotoxic T cells
What is the role of active cytotoxic T cell?
Defned against intracellular pathogens and cancer by binding to and lysing the infected/cancer cells
What stimulates memory B cell and memory T cells after 2nd explosure?
Memory Helper T cells
What does memory T cell stimulate?
Active cytotoxic T cells
What is the stages of phagocytosis?
1) Antign is engulfed by acrophage to become APC
2) APC stimulates Helper T cell which regulates B cells and Cytotoxic cell
3) Helper T cell transfer to Memory Helper T cell and stimulates memory B and T cell when there is a 2nd exposure
What are factors affecting severity of PID?
- Heterologus or homologous mutation
- Redundancy (No redudancy in CD3)
- How dmaanging the gene mutation is to protein function
- Co-expression of other mutations
- Lina of cells affected
Whar are PIDS affecing the innate immune system?
- Cogential aganulocytosis
- Chronic granulomatous disease
- Leukocyte adhesion deficiency
What is Leucocyte Adhesion Deficiency?
Defect in leucocyte diapedesis
What happens in Leucocyte Adhesion Deficiency?
- Leucocytes migrate by chemotaxis
Using adhesion receptors to move through vessel walls
Rolling - Selectins (e.g CD62L)
Adhesion - Integrins (e.g LFA-1)
What does Integrins have a role in?
Adhesion
Migration
Cell activation (changing the shape of the cell)
What is the structure of adhesion receptor?
CD18 -> alpha subunit (e.g CD11a) -> LFA-1 <- Ligands (e.g ICAM-1,-2,-3,-5)
Why is Leucocyte Adhesion Deficiency bad?
Mutation in the common beta chain
- A missing beta chain of integrin means all integrins are affected and cannot be expressed
- Leucocytes cannot cross into areas of inflammation
What is an example of mutation in common beta chain?
Patient suffered from chronic skin lesions
- After recieving bone marrow transplant the lesion healed as they had increased CD18 in the patient
