Immunology Flashcards
What is immunodeficiency
chronic infection
defective immune response
pathogens aren’t cleared
What are clinical signs of immune deficiency
serious infections
persistent infections
unusual infections
recurrent infections
what makes an infection ‘serious’
doesn’t respond to oral antibiotics (must be IV)
what are other features someone with immunodeficiency would display?
weight loss
failure to thrive
diarrhoea
cancer
what is a primary immunodeficiency disorder
genetic
at birth
not acquired from elsewhere
what are secondary immunodeficiency disorders
acquired from something
usually affects more than 1 cell type
what infections are associated with secondary immune deficiency
Human immunodeficiency virus
measles
What treatment interventions are associated with secondary immune deficiency
immunosuppressive drugs
anti-cancer agents
corticosteroids
What biochemical/nutritional disorders are associated with secondary immune deficiency
malnutrition (need nutrients to make WBC)
type 1 and 2 diabetes
mineral deficiencies
what are the classifications of primary immunodeficiency disorders
immune dysregulation
auto inflammatory disorders
defects in innate or adaptive immunity
What PID results in the earliest manifestation and mortality
respiratory diseases
What are upper respiratory complications caused by PID
sinusitis
otitis media
laryngeal angioedema
what are the lower respiratory complications associated with respiratory PID
malignancies
interstitial lung disease
pneumonia
bronchitis
Where can defects occur in neutrophils leading to immune disorders
development
trans-endothelial migration
killing by neutrophils
what defects in neutrophil development can occur
mutation in ELANE
enzyme needed for maturation
build up of precursor in bone marrow
How can defects in neutrophil development be treated
give individual recombinant cytokine that stimulates production of enzyme needed for maturation
How can defects in neutrophil trans-endothelial migration occur
ICAM1 not expressed on neutrophils
leukocytes can’t stick to endothelial cells and move into tissues
What are the clinical features in patients with neutrophils lacking ICAM1
redcurrant bacterial and fungal infections
high count of phagocytes in blood stream
What defects in neutrophil killing can occur
mutation in gene coding for NADPH oxidase complex
therefore neutrophil cannot produce ROS
can still kill
What are the clinical features in individuals with neutrophils lacking gene for NADPH complex
redcurrant fungal infections
recurrent bacterial infections
granuloma formation
Why do granulomas form when neutrophils lack the NADPH oxidase complex
macrophage can’t kill bacteria so it surrounds it to try and starve it of nutrients
What are the main treatments for phagocyte deficiencies
immunoglobin replacement therapy
management of infections through antibiotics
definitive therapies - stem cell transplant
What is SCID
Severe combined immunodeficiency
what are the causes of SCID
deficiency of cytokine receptors
deficiency of signalling molecules
metabolic defects
defective receptor arrangements
What occurs if there is a mutation of a component of IL-2 receptor
inability to respond to cytokines
failure of T cell and NK development
produces immature B cells
What is IL-2
T cell growth factor
What are the clinical phenotypes of SCID patients
unwell in early childhood
diarrhoea
failure to thrive
infections
skin disease
Why do SCID patients have recurrent viral infections
no CD8+T cells
therefore no cytotoxic T cells
Cells can’t recognise virally infected cells
Why are bacterial infections recurrent in SCID patients
No Tfh cells which are needed to help B cells make antibodies
why are fungal infections frequent in SCID patients
effector CD4+Tfh cells and antibodies are needed to fight fungal infections
What are the prophylactic treatments for SCID patients
prophylactic antibiotics
prophylactic antifungals
no vaccines
replacement immunoglobulin
What is the definitive treatment for SCID
stem cell transplant from MHC class identical donor
Which gene is essential for B cell development
BTK
What are the disorders of T cell effector function
cytokine production
cytotoxicity
T-B cell communication
killing of infected host cells
When are long-lived memory T and B cells produced
Primary immune response
Why do memory T and B cells have a more effective response (secondary)
present in greater numbers
persist in absence of antigens
less reliant on costimulatory molecules
already class switched
