Step I ABO blood typing

[Southpaw]

Are the antibodies we have against A and B antigens IgG or IgM, or both? I was reading in Lange Micro and saw that we develop IgM antibodies at 3-6 months of age. In another part it talks about where the IgG antibodies cross the placenta. And I'm sure that the anti-Rh antibodies are IgG. So is it just IgG that we have or both IgG and IgM?

 

[Taus]

the only blood type w/ IgG Ab's is type O.....all other blood types have anti-A and or B IgM...this is why you really only see ABO blood incompatibility b/w a mom-baby when the mom is type O and baby is A,B, or AB...as the mom's IgG can cross the placenta

 

[Army DOC DO]

yeah people who are blood type O have IgM to A and IgM to B but, they also have IgG to AB, which is the big concern for ABO incompatibility for ABO mothers with ABO A or B, because the IgG as you know crosses the placenta and causes a mild Hemolytic anemia in the baby, definitly nt as bad as if there were a Rh sensitization in the mother, because the anti-D crosses and causes really bad HEmolytic anemia and can cause kernicterus and hydrops fetalis, and cardiac failure in the newborn (most common reason these babies die.
People who are ABO A or B carry IGM anti-B and IGM anti A respectively and thuse it does not cross the placenta! happy Nerding!😀