Immunity Flashcards
Causes of toxic shock syndrome
Staph aureus
Group A strep
Which lab test can you do in toxic shock syndrome?
CK - raised
Quantitative test of B cell function particularly in children over 2
Antibodies to polysaccharide vaccines
Test of T cell function assessing mitogen proliferation
PHA (phytohemagglutinin)
What is PHA?
Stimulus to T cell proliferation
Diagnostic test for SCID with neurological abnormalities
PNP enzyme activity
What does positive hep B surface antigen indicate?
Either acute infection or chronic infection
How do you prove chronic hep B infection?
Either two positive hep B surface antigen tests three months apart, or simultaneous demonstration of HbsAg and IgG core antibody to core antigen (anti HBc)
Which mothers are at particular risk of passing hepatitis B on to their babies?
Those who have detectable ‘e’ antigen - high rates of active viral replication
What should infants of hep B ‘e’ antigen positive mothers receive at birth?
Immunoglobulin (HBIG) and immunisation, in separate limbs
What should infants of hep B surface antigen positive mothers receive at birth?
Vaccination within 48 hours and then complete the course
How long should you observe a patient post anaphylaxis?
6-12 hours
6 most important opportunistic infections in paediatric HIV?
CMV retinitis PCP Disseminated MAC Oesophageal candidiasis Cryptococcal meningitis Chronic cryptosporidium enteritis
Blood tests in SCID?
Lymphopenia
Low T cell numbers
Poor functional activity of T cell
Suspect if delayed separation of umbilical cord and no pus?
Leucocyte adhesion defect
How do you diagnose cyclical neutropenia?
Twice weekly FBC for 8 weeks
How is cyclical neutropenia treated?
GCSF, if treatment is needed
What is the mutation in Bruton’s?
btk gene (bruton tyrosine kinase) causing defective pre-B to B-cell transformation
Presents with gingivostomatitis at regular intervals
Cyclical neutropenia
Presents at 6m-2y with recurrent bacterial infections, reduced or absent lymphoid tissue, IgG, M, and A all low and very low or absent CD19/CD20
Bruton’s X linked agammaglobulinaemia
What is the treatment for Bruton’s
Regular IVIG or SCIG infusions
Presentation with eczema, recurrent bacterial infections and purpura
Wiskott-Aldrich
How is Wiskott-Aldrich diagnosed?
WASP expression
Which investigations should children with Wiskott-Aldrich receive?
Liver-spleen scan and serum immunoglobulins
What are the risks of Wiskott-Aldrich?
Serious herpes infection, malignancy, autoimmunity
What is the treatment for Wiskott-Aldrich?
Platelet transfusion if indicated, BMT (can be curative)
Presents with recurrent infections and low IgG +/- low IgA in infants
Transient hypogammaglobulinaemia of infancy
Immune-related blood tests in HIV
Raised IgG
Reversed CD4-CD8 ratio
Presents early in infancy with failure to thrive, chronic diarrhoea, recurrent infections, infection with unusual organisms and chronic candidiasis
SCID
What investigations should be done in suspected SCID?
Serum immunoglobulins
Lymphocyte subsets
PHA stimulation tests
Cause of chronic granulomatous disease
Inherited defect in the NADPH dependent oxidase enzyme system, unable to deal effectively with certain phagocytksed organisms
Presents with suppurative infection, macrophage activation and formation of granulomata
Chronic granulomatous disease
Test for CGD
Flow cytometry to assess neutrophil respiratory burst activity
Lab tests in ataxia telangiectasia
Low IgA
Elevated serum alpha fetoprotein
Increased white cell sensitivity to irradiation
T cells may be low
Presents with very high IgE, eczema, staphylococcal abscesses
Hyper IgE syndrome (Job syndrome)
Cause of roseola infantum
HHV6
Cause of molluscs contangiosum
Poxvirus
What should be regularly checked in children on immunoglobulin therapy?
LFTs
Hep C status
Trough Ig levels
Test for LAD?
Flow cytometry for CD11b
