Prolonged anemia after HDFN

[Mabel Adams]

We are dealing with a 24 day old baby who just had his second top up transfusion.  He was born at term to an A neg mom who was discovered at that time to have anti-D.  Her titer was 32.  She had a negative antibody screen at the beginning of the pregnancy but was not tested when she got her 28 week dose of RhIG.  The baby was A pos and had a strongly pos DAT.  These results triggered us to test the mom and find the anti-D (we don't do routine screens on all OB admits).  The baby had a Hct at birth of 40, so a bit low but not worrisome.  He was under bili lights for 5 days and went home with a bili of about 9 and was under home bili lights also. Peak bili was 15.  Over this time, his Hct slowly drifted downward. It was 30.7 when he was discharged at 5 days old. He was followed as an OP for bili and H&H. He had to come in for a transfusion (his first) when he was 11 days old because his Hct was down to 17.  The morning after that transfusion his Hct was 27.  Now some two weeks later he had to come back in for another transfusion because his Hct on Saturday was 20.4 and he was acting tired--feeding taking a long time.  His retic count is elevated although not as high as it was before the first transfusion.  His LDH is normal. His bili is still a bit high at 3.3 but he does not appear jaundiced.  His direct bili is normal. After the latest transfusion, they have him up to Hct 26.5 and sent him home again.  He still has a pos DAT(although weaker than before) and has anti-D in his plasma.  He has gained weight and is developing normally.  The MD doesn't think he is losing blood (other than being sampled every 2-3 days for testing).  We transfused O negative blood both times from the same donor.  Baby has not had any viruses and seems otherwise well.

 

If anyone has ever seen such a case, please let me know what the cause was determined to be.  Or I will take our usual wild speculation and ideas of things to look for.  There is an idea from the doctor of autoimmune hemolytic anemia.  We have not done an eluate on his most recent specimen--there probably aren't many red cells left to test. I would think his bili and his LDH would be higher in AIHA.

[David Saikin]

It seems that if the child still is demonstrating anti-D that that antibody is the culprit.  The baby is still making Rh+ rbcs so these will continue to be affected until the passive ab is effectively neutralized or just disappears due to normal IgG half-life.  I'd do another elution to verify the culprit rather than jump the gun about AIHA.

[Malcolm Needs ☆]

Hi Mabel,

 

I would agree with David.  The baby will be producing some D+ red cells, which, of course, are, at the same time, being destroyed by the maternal anti-D.

 

In addition, though, the very fact that the baby has been transfused with group O, D- units would tend to suppress the baby's erythropoiesis, because the chemoreceptors for O₂ will be fooled into thinking that the baby is producing sufficient red cells of his/her own, by the fact that the baby's Hb and Hct would be "normal" for a while, whilst the transfused red cells are in its circulation.  On top of all that, even a "normal" baby's Hb will drop fairly rapidly after birth, as it is receiving oxygen from the atmosphere, rather than from the maternal circulation (a normal physiological progression), so I would think that things will settle down fairly soon.

 

The only other thing that could be depressing the baby's natural erythropiesis is if the mother has produced another antibody, in addition to the anti-D, directed against a low frequency antigen expressed on the baby's red cells, probably within either the Kell or Gerbich Blood Group System, as antibodies within these Blood Group Systems are known to cause suppression of erythropoesis in the baby, derived from a gene inherited from the father.  This is in the area of looking for zebras when you hear hooves, but you never know.  To prove this (!), you would have to adsorb out the maternal anti-B and anti-D, and then react the maternal adsorbed plasma against the paternal red cells - and good luck with that one!

 

The idea of an AIHA within the baby is, as far as I am concerned, a non-starter (or, at the very least - highly unlikely), as the baby would be having to produce his/her own auto-antibodies, and they would probably have to be IgG in nature, and that just ain't going to happen!

 

Personally, I wouldn't worry too much.

[R1R2]

I have seen this several times with anti D and I agree with Malcolm.   I wouldn't worry too much.  

Edited October 19, 2015 by R1R2