In cord blood, elution revealed antibodies against which red cell antigens?

In cord blood, elution revealed antibodies against which red cell antigens?

• A. Anti-D and Anti-C
• B. Anti-D only
• C. Anti-C only
• D. Anti-Lea and Anti-I

Answer: (A)

In cord blood, the elution procedure pulls off antibodies that are already bound to the newborn’s red cells by maternal IgG that crossed the placenta. The Rh system is the most relevant here because anti-D is highly immunogenic and commonly formed in Rh-negative mothers. If the fetus expresses the D antigen and the mother has developed anti-D, those antibodies will coat the fetal red cells and be detectable after elution. If the mother also has anti-C from prior exposure and the fetus has the C antigen, anti-C can similarly coat fetal cells and be recovered. So the eluted antibodies would reflect antibodies against both D and C. Antibodies against Lea and I are not typically seen in this context because they are not part of the Rh immunization scenario and are usually IgM, which do not cross the placenta in the same way or bind fetal cells to yield eluted antibodies.

In cord blood, the elution procedure pulls off antibodies that are already bound to the newborn’s red cells by maternal IgG that crossed the placenta. The Rh system is the most relevant here because anti-D is highly immunogenic and commonly formed in Rh-negative mothers. If the fetus expresses the D antigen and the mother has developed anti-D, those antibodies will coat the fetal red cells and be detectable after elution. If the mother also has anti-C from prior exposure and the fetus has the C antigen, anti-C can similarly coat fetal cells and be recovered. So the eluted antibodies would reflect antibodies against both D and C.

Antibodies against Lea and I are not typically seen in this context because they are not part of the Rh immunization scenario and are usually IgM, which do not cross the placenta in the same way or bind fetal cells to yield eluted antibodies.