learning outcomes Flashcards
Define primary immune deficiency
- disorders in which part of the body’s immune system is missing or does not function normally
- predisposes to infections, cancers, autoimmunity
- most primary immunodeficiencies are genetic disorders
Define secondary immune deficiency
the cause of the immune deficiency is secondary in nature (i.e. caused by other disease, drug treatment, or environmental exposure to toxins
explain the classification of primary immune deficiency disorders
- mutations: severe combined immunodeficiency (SCID)
- polygenic: common variable immunodeficiency (CVID), IgA deficiency, specific antibody deficiency
- autoimmunity: autoimmune polyendocrinopathy candidiasis ectodermal dysplasia (APECED)
Give examples of primary disorders of T cell, B cell, phagocyte and complement function
defects in T cells: infection with intracellular organisms (protozoa, herpes. candida, and mycobacteria)
phagocytes: infections with staphylococci, gram-negative bacteria, and fungi
complement: meningitis
Understand the causes of primary immunodeficiency
mutations: permanent alteration in the DNA sequence that makes up
a gene
polymorphisms: variation at a single base pair
polygenic: disorders caused by the combined action of more than one gene
Illustrate the complications of immune deficiency disorders
mutations: SCID
- die in the first few months of life unless treatment is given
- history of early deaths in maternal uncles
polymorphism
- human leukocyte antigen (HLA) alleles can affect the outcome of infections
- mannan-binding lectin (MBL) (collagen-like protein that binds sugars in bacterial cell walls) activates the classic complement pathway
polygenic:
- CVID: low levels of total IgG. Levels of IgA and IgM and numbers of B and T cells are variable; causes recurrent respiratory tract infections
- specific antibody deficiency: develop recurrent infections with pneumococcus or Haemophilus spp. despite normal total IgG.
list the clinical features of primary immunodeficiency
unusual or recurrent infection
diarrhoea, unusual rashes
understand the principles of the treatment of primary immunodeficiency