Type&Screen Flashcards
IgG
Monomer Most common Abs Cross placenta Bind complement Leads to phagocytosis 4 subclasses: IgG1-4 IgG1: Fixed complement, 23 days, bind macrophage via Fc IgG3: Fixed complement, 8 days, bind macrophage via Fc
Complement pathway
- Classic: via C1, triggered by IgM, IgG
- Alternative: low grade, constant, via C3. Normal: inactive bound C3 via DAF (CD55). Abnormal: Paroxymal Nocturnal Hemoglobinuria
- Lectin: via sugar, no need C1
Landsteiner’s law
Have antigen, shouldn’t have antibody
Define “naturally occurring”
- Immune exposure to the environment (bacteria, pollen)
- Not require exposure to blood transfusion
- Noticeable 3-6 months
Isoagglutination
IgM, IgG, IgA
Cause hemolysis by fixing complement
At RT (due to IgM)
Where ABO?
RBC, WBC, PLT
endothelium
epithelium
secretion
How much blood can cause an acute hemolytic transfusion reaction
10mL
Anti-A,B
Produced by group O –> react A or B cells
Mostly IgG –> cross placenta
Cause ABO HDFN (Hemolytic Disease Fetus & Newborn)
ABO genetic
H, h: chromosome 19
A,B,O: chromosome 9
* O = amorph: enzyme produced has no function
Precursor chains
Type 1: 1-3 terminal galactose & N-acetylglucosamine
Secretion & Plasma
Type 2: 1-4 terminal galactose & N-acetylglucosamine
RBC & tissue
H-antigen
HH or Hh
a-2-L-fucosyltransferase: bring L-fucose to terminal galactose
Amount of H: O>A2>B>A2B>A1>A1B
A-antigen
AO, AA, AB
a-3-N-acetyl-D-galactoseamyltransferase: bring N-acetyl-D-galactosamine to terminal Galactose
Requires L-fucose
B-antigen
BO, BB, AB
a-3-D-galactosyltransferase: bring D-galactose to terminal galactose
Requires L-fucose
Bombay
Lack of H antigen –> hh –> Denote: Oh
Plasma contains all types of Abs: anti-A, anti-B, anti-A,B, anti-H
Cause AHTR
Able to pass on A and B genes
ABO in newborns
- Weak expression –> no isoagglutination until 4 months –> No reverse test
- Maternal Abs can cross and attach to baby’s RBC –> no severe as weak ABO