Diseases in the Immuncompromised Flashcards
what is the most common form of SCID
X-linked
what defect causes X-linked SCID
defect in the gamma chain of the cytokine receptor or Jak3 gene
a lack of which IL prevent T cell development
IL-7
which cytokines usually bind the receptor which is defected
IL-2 IL-4 IL-7 IL-9 IL-15 IL-21
which activity is affected in X linked SCID
cytokine responses
what activities are affected in the various forms of SCID
t cell development, lymphocyte survival, vdj rcombination, tcr signalling
what defect causes digeorge syndrome
deletion of chromosome 22
what are the symptoms of digeorge syndrome
heart defects, cleft palette, autism, other learning difficulties
which actvity is affected in digeorge syndrome
thymic development
how does a lack of thymus in Digeorge syndrome cause prblems
there are no mature T cells
how do SCID and CID differ
in CID there is still some residual function
how is there a decrease in antibodies in Digeorge syndrome
a lack of T cells means a lack of b cell activation from t cell dependant antigens
what is the treatment for digeorge syndrome
thymic transplant
what type of immunodeficiency is bruntons aggamaglobulineamia
humoural immunodeficiency
what process is affected in bruntons aggaaglobulinaemia
maturation of b cells
what causes the lack of b cells in bruntons aggamaglobulinaemia
lack of Btk in the bone marrow
is bruntons aggamaglobulinaemia x linked
yes
how is bruntons agammaglobulinaemia treated
Ig therapy
what sort of infections are patients with b cell defects likely to get
Pyogenic bacteria infections, viral infections and infections with strep. pneumonaie
how do pyogenic bacteria infect patients with B cell defects
they have polysacccharride capsules which are not recognised by macrophages and neutrophils
how are pyogenic bacteria usually cleared
complement and antibodies
why are people with b cell defects susceptible to viral infections
because antibodies are important in neutralising viruses in the gut
what virulence factors does streptococcous pneumonaie acquire when it becomes pathogenic when the host is immunocompromised
invasins, adhesins and immunogenic cell wall components
what sort of immunodeficiency is leaves a patient susceptible to neisseria meningitis
complement deficiency
what specific defect is linked to susceptibility to infection with niesseria meningitis and why
defects in the membrane attack complx as this allows intracellular survival as the host cant perform extracellular lysis
what are the two types of innate immunodeficiency
defects in inflamatory response and defects in phagocyte killing
what is process is effected in chronic granulomatus disease (CGD)
phagocyte killing
what is the defect in CGD
NADPH oxidase
what sort of disease is CGD
innate immunity
how does the defect in CGD result in a compromised immune system
it causes difficulty in forming reactive oxygen species which impares bacterial killing
what are the results of chronic granulomatus disease
recurrant infections incl pneumonia, absesses of the skin, septic arthritis, fungal infection and impetigo
what are secondary immunodeficencies which can cause problems with the innate immune system
burns, trauma, surgery, smoking,CF, implanted devices, prolonged antibiotic therapy
under what circumstances is a person susceptible to infection from staph. aureus and staph. epidermis
when the person has defective physical barrier or clearance mechanism
what are the results of infection with staph aureus
boils or staphylococcal scalded skin syndrome in children
what sort of bacteria is Staph. epidermidis
gram positive, catalase positive, coagulase negative cocci.
which antibiotics is staph epidermidis resistant to
vancomycin penicillin and methicillus
what is used to treat staph epidermis
novabiocin
how does staph epidermis form biofilms
it produces an extracellular slime which can adhere to plastic surfaces via van der waals and anchor using adhesion molecules such as pili
what are common infections in patients suffering from cystic fibrosis
s. aureus, haemophilus influenzae, pseudomonas aeruginosa and B. capecea
what do the bacteria which commonly infect CF patients have in common
they are resistant to common antibiotics
what 3 things causesreduced circulating neutrophils
radiotherapy, chemotherapy, leukeimia
what are the most common infections in patients with phagocyte defects
S. aureus, S. pyogenes, Gram negative rods and P. aeruginosa
which bacteria are patients with T cell defects likely to be infected by
mycobacterium avium and toxoplasma gondii
is infection rate of mycobacterium avium inversely related to CD4+ counts or CD8+ counts
CD4+
what is toxoplasma gondii
an intracellular protazoa
what percentage of adults does toxoplasma gondii latently infect
35%
what does the reactivation of latent toxoplasma gondii lead to in T cell deficient patients
toxoplasmic encephalitis
how does infection from toxoplasma gondii usually occur
ingesting oocytes from unwashed veg or tissue cysts in undercooked meat
