Immunodeficiency Flashcards
What are the 2 types of immunodeficiency?
Primary and secondary
What is primary immunodeficiency?
It is a relatively rare form of immunodeficiency that usually manifests in children as a result of intrinsic defects in the immune system/
What is secondary/acquired immunodeficiency?
It is a common form of immunodeficiency that primarily affects elderly due to underlying disease(s) affecting the immune system.
What is a common clinical manifestation of immunodeficiency?
Infections
- reactivation of latent infections
- opportunistic infections
- unusually severe/ widespread/ frequent/ persistent/ recurrent infections
What are some examples of primary immunodeficiency conditions?
1) DiGeorge syndrome (no thymus)
2) CD3-Xi chain (defective T cell maturation)
3) Hyper IgM syndrome (defective B cell maturation)
4) IFN-y receptor deficiency (defective APC/T cell interaction)
5) Chronic granulomatous disease/leukocyte adhesion deficiency (neutrophil dysfunction)
6) Severe combined immunodeficiency (Failure in both B and T cell development)
What is Severe Combined Immunodeficiency (SCID)?
Is it a heterogenous group of genetic disorders resulting in BOTH B and T cell development failure.
Describe what is the passive immunisation in neonates?
Transplacental maternal IgG transfer during the 3rd trimester
When do primary B cell deficiencies manifest?
> 3-4mths of age (after maternal IgG degrade < protective conc.)
What are some examples of secondary/acquired immunodeficiency?
1) HIV infection (↓ CD4+ Th cells)
2) Irradiation/chemotherapy (decreased bone marrow precursors)
3) Immunosuppression for graft rejection and inflammatory diseases (↓/dysf(x) of leukocytes)
4) Protein/calorie malnutrition (↓lymphocyte maturation and f(x))
5) Removal of Spleen (↓phagocytes)
What are some examples of immunosuppressive therapies?
1) Corticosteroids (esp high dose and duration)
2) Immunosuppressants
3) mAbs for cytokine and immune cell inhibtion
4) Myeloablative chemo/radiotherapy
What are the common px categories that would be on immunosuppressive therapies?
1) Asthma
2) Autoimmune disease
3) Transplants
4) Cancer
Why are px on chemotherapy at higher risk of septicaemia from extracellular bacterial and fungal infection?
Neutrophils that are responsible for phagocytosis of fungi and bacteria have a rapid turn over and are thus highly affected by chemotherapy.
Why are organ transplant recipients advised to minimise sun exposure?
They would be on immunosuppressants and thus have impaired tumour surveillance → ↑risk of skin tumours
