Immunology Flashcards
what are the cells of the innate immune system
phagocytes
Nk cells
what are the cells of the acquitted/adaptive immune system
B cells
T cells
what immune cells target bacteria
phagocytes
antibodies and b lymphocytes
complement
what immune cells target viruses
t lymphocytes
antibodies and b lymphocytes
what immune cells target fungi
phagocytes
t lymphocytes
eosinophils
what immune cells target protozoa
eosinophils
t lymphocytes
what immune cells target worms
eosinophils
mast cells
what are the physical barrier to infection
skin
- antimicrobial secretions from keratinocytes
- sebaceous/sweat glands
- antigen presenting cells in skin
mucosa
- antimicrobial substances. eg. lysozyme
- IgA
- Gastric acid
what are some risk factors to impaired barrier function in skin
eczema psoriasis erythoderma tine pedis (athletes foot)/ cracking of skin ulcers/pressure sores
risk factors to impaired barrier function in the lungs
cystic fibrosis
COPD
poor swallow
risk factors to impaired barrier function GI
Impaired bladder function
urinary stasis
what do phagocytes do
ingest organisms following opsonisation
kill via oxygen killing or independent mechanisms
control bacteria and fungi
what conditions cause phagocytes deficiency
haematological malignancy
cytotoxic chemotherapy
hat are the 2 types of helper T cells
helper T cells
cytotoxic T cells
what causes T cell deficiencies
HIV pneumonia
Lymphoma
Primary immunodeficiency syndromes
what do B cells do
mature into plasma cells and produce immunoglobulins
what do immunoglobulins protect against
recognised antigens also
opsonise microbes for ingestion by phagocytes
what is the firs immunoglobulin to be produces
IgM- Has a weak affinity so does not bind very strongly to pathogen
what is the most abundant immunoglobulin
IgG - produced after IgM - much stronger affinity
where are B cell deficiencies seen
myeloma
primary immune deficiency syndromes
certain immune suppressants
what cells are infected by HIV
CD4+ T lymphocytes
what does HIV cause a high risk of
invasive pneumococcal disease irrespective of CD4 count
what is hyposplenism
decreased spleen function
what causes hyposplenism
splenectomy functional hyposplenism (sickle cell anaemia, cirrhosis, coeliac disease)
what does reduced spleen function cause susceptibility to
encapsulated organisms
strep pneumoniae
haemophilus influenzae
neisseria meningitidis
what is the aim of immunosuppression
to reduce the damage caused to the body by the immune system
when are immunosuppressive drugs used
autoimmune conditions
transplants
cancers
what are the side effects of immune suppression
- blunted response to stimulus
- do not have normal symptoms and signs of infection
- often lower threshold for treatment
what do steroids increase the risk of
a wide range of infections particularly fungal infections
what does anti-TNFa therapy increase the risk of
mycobacterium tuberculosis
fungal infections
what do purine analogues increase the risks of
viral infections
pneumoncystitis jirovecci
when are prophylaxis given in immunosuppression
HIV - cotrimoxazole
Bone marrow transplant
describe the immune response in sepsis
disordered immune response to inflammation
cause inappropriate immune activation and inflammatory cascade
unchecked inflammation leads to organ dysfunction
what causes cardiovascular dysfunction in sepsis
hypotension due to wide spread vasodilation leading to fall in peripheral resistance
needs fluid resuscitation
what causes pulmonary dysfunction in sepsis
endothelial injury with lung tissue/capillar leak
diffuse alveolar oedema
respiratory failure, needing supplemental oxygen
what causes renal dysfunction in sepsis
acute kidney injury, a rise in urea/creatine due to hypoperfusion
what causes CNS dysfunction in sepsis
delirium/acute confusion due to cerebral hypoperfusion
drowsy, decreased conscious level
what causes lactic acidosis in sepsis
diffuse tissue hypoperfusion leads to anaerobic metabolism and lactic acid production causing acidosis
