Interesting Maternal antibody

[bbbirder]

Infant: B neg* with positive DAT

[*Rh pos for weak D(Du), but appears to be false positive due to positive DAT]

Tested cord serum: postive antibody screen and positive with A1 and B cells at AHG

Obtained mother's blood: O positive with positive antibody screen. Prenatal: Opos with neg antibody screen 6 months prior. G3P1 (with this infant her first live birth)

Antibody ID: anti-c

Antigen typing on Mom: C pos, e pos, c neg, E neg

Antigen typing on infant: c pos, e pos, C neg, E neg

Any comments? (I am leaving out a little information at this point)

[Mabel Adams]

Mom is not genetic mother of baby? Donor egg? One of mom's gene's is for a C deletion and baby inherited that one??? Or am I looking for zebras when hoofbeats only mean horses?

(Sideline: I assume the A1 and B cells used were reagent reverse cells so they are both Rh neg--thus both c pos. So we don't know if the reactions to them are ABO or the anti-c, right? Don't know how much you would care either.)

[bbbirder]

Mabel,

You got it just right. This was a donor egg. Mom is R1R1 and baby is rr. (It is a little more obvious when you write it this way.) This is a real case we just had.

Baby did fine, bilirubin went up to 17, but otherwise no problems. Pathologist has contacted her OB to recommend genetic counseling if she is planning future pregnancies.

I guess some of the other possibilites are: Mother is a chimera, mother got a stem cell transplant in the past, gene deletion of some sort. Are there others?

You did raise a good point about the anti-A,B: At this moment we don't have any A or B donor units that are c-neg, but we'll be screening some soon enough and will test, but she almost certainly has anti-A,B since she is an O.

Linda Frederick