immunology Flashcards
type I immediate hypersensitivity reaction
Immediate and late phase: IgE antibodies bind to mast cells and cause degranulation (asthma, food allergies, hayfever).
<30 mins, late phase 2-12 hours
type 2 hypersensitivity reaction
cytotoxic antibody: an antibody dependent reaction seen in conditions such as haemolytic disease of the newborn and transfusion reactions and well as goodpastures (IgM, IgG and IgA) haemolytic anaemia, blood transfusion reactions,
Type 3 hypersensitivty reaction
insoluble antibody-antigen complexes are deposited in tissues which triggers complement activation causing causing tissue damage (e.g. RA, SLE, serum sickness, hypersensitivity pneumonitis).
Type 4 hypersensitivity reaction
T Cell mediated reaction involving CD8+ cytotoxic T cells and CD4+ helper T cells. (contact dermatitis, type 1 DM, SJS, TEN, DRESS syndrome, rash).
type I immediate hypersensitivity reaction timing?
<30 mins, late phase 2-12 hours
type 2 hypersensitivity reaction timing?
minutes to hours
type 2 hypersensitivity reaction effector molecule?
IgM, IgG and IgA
type 2 hypersensitivity reaction target or antigen?
Red Blood Cells, platelets
Type 3 hypersensitivity reaction timing?
1-3 weeks after exposure
Type 3 hypersensitivity reaction effector molecule
antigen-antibody complexes
Type 3 hypersensitivity reaction target or antigen?
Blood vessels, liver, spleen, kidney, lung
type 4 hypersensitivity reaction timing
2-7 days after drug exposure
type 4 hypersensitivity effector molecule
lymphocytes
type 4 hypersensitivity reaction target or antigen
mycobacterium tuberculosis, chemicals
live attenuated vaccines?
parenteral live attenuated viral immunisations(MMR, Varicella
CGD:
X linked: most on the x chromosome : 91 PHOX
Autosomal recessive
nicotinamide-adenine-dinucleotide-phosphate oxidase (NADPH in low levels
neutrophils don’t have the ability to kill pathogens (no reactive oxygen.
- pneumonia
- abscesses
- septic arthritis
- osteomyelitis
non disease causing normall: particularly suceptible to Nocardia/ Staph aureus/ serratia / burkholdia/ aspergillus**
mulch pneumonitis is PATHOGNEMONIC
LAD
3 types B-chain integrin called CD18: normal neutrophil aggregation but cannot extravasate,
- features: delayred cord separation, recutrrent skin infections, moral mucosa. UTI and ecthema gangrenosum.
A WBC differential will reveal extremely elevated levels of neutrophils (on the order of 6-10x normal) because they are unable to leave the blood vessels.
Neutropenic (three conditions)
kostmans : HAXI OM/cellulitis/resp trat)
Neonatal alloimmune neutropenia: sepsis and oomphalitis
Schwachman diamon: steathorreah (pancreatic insufficiency/ FTT/ stomatitis, apthous ulcers and stomatitis secondary to clostridium
X-linked agammaglobulimaemia (bruton’s tyrosine kinase)
well until 6 months encapsulated (s. pneumo /hib) rotavirus: chronic diarrhoea enterovirus (chronic meningioencephalitis protozoal: giardiasis Paralytic polio with vaccine
attendance at 6 months, The diagnosis is probable when blood tests show the complete lack of circulating B cells (determined by the B cell marker CD19 and/or CD20), as well as low levels of all antibody classes, including IgG, IgA, IgM, IgE and IgD.
Selective IgA
It is defined as an undetectable serum IgA level in the presence of normal serum levels of IgG and IgM, in persons older than 4 years.
sinopulmonary infections, autoimmune, allergy
- increased ractions to blood transfusions
Hyper IGM
CD40 ligand signalling defect - unable to class switch - so heaps of IgM and no IgM, IgA or iGE.
susceptible to T cell and macrophage infections, such as PCP and cryptosporidium. usually in people’s lungs however hyper IgM not able to fight it off without bactrim.
x linked recessive
Diagnostic test for CGD?
The nitroblue-tetrazolium (NBT) test is the original and most widely known test for chronic granulomatous disease. the higher the blue score. the better the cell is at producing reactive oxygen species.
Dihydrorhodamine (DHR) 123 test: respiratory burst capacity of neutrophils
complement disorders
Deficiencies of early components of the classical complement pathway, including C1, C4, and C2, are associated with encapsulated bacterial infections like Streptococcus pneumoniae and Haemophilus Influenza type b and hereditary angiodeme due to the clotting pathway
C3 deficiency is associated with severe recurrent pyogenic
Alternative (properdin deficiency, Factors D and B): Properdin deficiency increases the susceptibility to bacterial infections of the Neisseria family of organisms. The most prominent in the group is N. Meningitis, the cause of a serious form of meningitis
T Cell deficiencies
Severe Combined Immune Deficiency (SCID), Ataxia-Telangiectasia, Wiskott-Aldrich Syndrome and DiGeorge Syndrome