Lecture 21 - Immune deficiencies Flashcards
(38 cards)
what are the two main types of immune deficiencies?
- primary (born with it)
- secondary (event causes low immune response)
true or false, immune deficiencies are really common
false, they are rare but well studied
what is the result on infection when an individual has defective phagocytes?
results in recurring infections and fevers
what are the four types of phagocyte defects?
deficiencies in:
- production of phagocytes
- phagocyte adhesion
- phagocyte activation
- phagocyte killing of organism
describe how leukocyte adhesion deficiencies cause disease?
defect in LFA1 integrin adhesion molecule prevents phagocyte from adhering to the endothelium to get to site of infection
- therefore particularly effects neutrophils
what will be different at the site of infection of someone with leukocyte adhesion deficiencies vs normal?
- no pus at the site of infection due to lack of neutrophils getting to the site
what type of phagocyte deficiency is chronic granulomatous disease?
deficiency in phagocyte killing of organism
how does chronic granulomatous disease happen?
very rare disease where phagocytes can’t produce reactive oxygen species and can’t kill ingested bacteria
what does a defect in any protein involved in the complement pathway lead to?
a common convergence on C3 -> C3b
what bacteria are people with complement deficiencies resulting in reduced c3b more susceptible to and why?
pyogenic bacteria (staph aureus) and neisseria species
- because these bacteria are more complement sensitive.
what types of bacteria are most susceptible to the MAC?
neisseria species - MAC is the primary mechanism of pathogen elimination
what is an example of defects in B cells and antibody production?
congenital agammaglobulinemias
how is congenital agammaglobulinemias characterised?
by recurrent infections with pyogenic bacteria
when do symptoms of congenital agammaglobulinemias ocurr?
7-9 months after birth, because maternal antibodies wear off and babies antibodies are becoming predominant
what is T cell specific immunodeficiency
generally causes low numbers of T cells but the cells also show functional defects
what is an example of T cell specific immunodeficiency?
wiskott-aldrich syndrome WAS
how does wiskott-aldrich syndrome cause T cell specific immunodeficiency?
defect in WAS gene which causes issue in forming the immune synapse between an APC and a T cell, and so T cells dont respond to T cell cross-linking or activation
what is severe combined immunodeficiency SCIDs?
mutations that result in compromised B and T cells
- low lymphocyte numbers in blood
when is SCIDs diagnosed?
5 months after birth
what are examples of SCIDs?
- deficiency in ADA that leads to increased dATP
- X linked SCID causes lack of cytokine signalling
what are the symptoms of SCID?
prolonged diarrhea, severe infections, pneumonia
without diagnosis, when would babies die from SCIDs?
1-2 years
who was the boy in the bubble?
he had an X linked SCID and was born into a germ-free condition. his sister gave him a bone marrow transplant which gave him cancer forming EBV. died age 12
how can people become immune compromised (secondary immunodeficiency)?
- infection such as HIV
- aplastic anemia
- drugs
- systemic and chronic diseases such as burns and renal failture
- old age, stress, depression etc
