Immunodeficiency Flashcards
Name 3 mechanisms by which antibodies bind to antigens to enhance phagocytosis
Neutralisation
Agglutination
Precipitation
Name the mechanism direceted by antibodies that enables cell lysis
Activation of complement system
How to cytotoxic T cells act?
Bind to infected cells and perforin makes holes in infected cell’s membrane and enzyme enters. Infected cell is destroyed.
What are the cytokines released by innate cells that direct the immune system to carry out more appropriate response
Pathogen associated molecular patterns (PAMP) e.g. directs T cells to develop into Th1, Th2 or Treg
Primary immunodeficiencies
Genetic defect in component of immune system
Secondary immunodeficiencies
Secondary to the effects of external factors
IRAK4 deficiency -PRR activation defect
TLRs become activated and trigger a cascade of cytokine release- IRAK is essential in the production of an inflmmatory response- as adaptive immune system develops, other pathways offer protection-most severe in early life.
Chronic granulomatous disease
Defect in phagocytosis affecting primarily males. AR. Neutrophils are unable activate proteolytic enzymes in phagosome. Defect in NADPH-oxidase complex-transports H+ across phagosome membrane.
Diagnosis of chronic granulomatous disease
Nitroblue tetrazolium test- normally neutrophils release oxygen radicals which converts blue dye to black. Defect = no chance in colour
Clinical presentation of CGD
Osteomyelitis, pneumonia, swollen lymph nodes, ginigivitis-gum disease, non malignant granuloma, inflammatory bowel disease
Which complement pathways activate C5 to form pores in bacterial cell wall?
All 3
Diagnosis of complement deficiency
Sheep RBCs incubated in patient’s serum-in competent terminal pathway- lysis of RBCs.
Clinical presentation of complement deficiency
Meningococcal infections
Treatment for people with complement deficiencies
Vaccines for meningococcal e.g. penicillin prophylaxis
X linked agammaglobinaemia
Defect in B cells- antibody deficiency. Recurrent bacterial infections e.g. sino pulmonary infections. Usually diagnosed 1-2 yr, since maternal IgG protects.
