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* ABO incompatibility
  yazdoc - 08/09/09 20:18
  IgM does not cross placenta but ABO incompatibility leads to jaundice. why?

what is sulfosalicilic acid dipstick?
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* Re:ABO incompatibility
  acyclovir99 - 08/09/09 20:25
  On subsequet exposure in the 2nd pregnancy,the already primed B cells produce a much larger response,n this time with IgG which does cross the placena.
In the fetus it forms Ab-Ab complex on fetal RBC membrane leading to phagocytosis of these RBCs in RE system
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* Re:ABO incompatibility
  acyclovir99 - 08/09/09 20:26
  I meant Ag-Ab complexes.  
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* Re:ABO incompatibility
  snowhite99 - 08/09/09 20:27
  if its anti AB-----------DEN its ig g ...which can cross...
bt anti A n anti B ----------ig M...cant cross..

sulfosalicilic acid dipstick------------acid ppt for protein...i guess microprturia
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* Re:ABO incompatibility
  yazdoc - 08/09/09 20:48
  but isnt ABO incompatibility seen in the first pregnancy and gets better with subsequent and Rh incompatibility is vice versa.

so if mom is blood gp O, she will have anti a, anti b and anti ab and hence anti ab will do harm
thanks snowwhite

i read that sulfosalicylic can detect bence jones so was curious
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* Re:ABO incompatibility
  omegamd - 08/09/09 22:04
  i do not remember ever reading ABO incompatibility getting better but by that does not sound right.  
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* Re:ABO incompatibility
  acyclovir99 - 08/09/09 22:09
  ABO incompatibility

ABO incompatibility disease afflicts newborns whose mothers are blood type O, and who have a baby with type A, B, or AB.

Ordinarily, the antibodies against the foreign blood types A and B that circulate in mother's bloodstream remain there, because they are of a type that is too large to pass easily across the placenta into the fetal circulation. Some fetal red cells always leak into mother's circulation across the placental barrier (mother and fetal blood theoretically do not mix, but in actuality, they do to a small degree).

These fetal red cells stimulate the formation of a smaller type of anti-A or anti-B antibody which can pass into the baby's circulation and there cause the destruction of fetal red cells. The increased rate of destruction of red cells causes a subsequent increase in waste product production. This excess waste product, bilirubin, can overwhelm the normal waste elimination processes and lead to jaundice, the presence of excess bilirubin.

ABO incompatibilty get better with RH incompatibility.
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* Re:ABO incompatibility
  acyclovir99 - 08/09/09 22:16
  Moms antiA n anti B antibodies r IgM antibodies that cant cross the placenta.However ,fetal RBCs cross the palcenta n stimulate maternal Immune system to form IgG antibodies which cross the placenta and cause hemolysis n jaundice.  
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* Re:ABO incompatibility
  acyclovir99 - 08/09/09 22:17
  in fetus.  
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* Re:ABO incompatibility
  acyclovir99 - 08/09/09 22:31
  ABO incompatability protects against Rh Incompatability :

due to the presence of maternal IgM antibodies against fetal ABO Blood group.The few fetal red blood cells that are mixed with the maternal circulation are destroyed before Rh sensitization can proceed to a significant extent.
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* Re:ABO incompatibility
  wishesbest2009 - 08/10/09 02:19
  excellent explanation, acyclovir99!  
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