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comment_9252

We have an OB that with the last pregnancy that we identified an Anti C. She had a 4+ DAT and typed as C positive. Since we eluted an Anti C from the cord blood we assumed that our antigen type on the Mom has a false positive and put a disclaimer that we were unable to confirm the antigen type. She is a dentist (happens to be mine) and said that she is only taking vitamins. I didn't think to ask if diabetic or has lupus or RA, etc. She is pregnant again and still has a 4+ DAT and Big C 3-4+ on her panels. We did a chloroquine and typed her as Big C, and little e positive, Big E and little c negative. Elution shows a little e and Big C specificity. Titer of the auto antibody is 1:2. So what do we explain to the doctor and the dentist? Anyone have any information concerning pregnancies with auto antibodies? Thanks a lot. Mary Carton, Eliza Coffee Memorial

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comment_9253

Are you using gel or capture? I find it hard to believe that a tube reaction of 3-4+ (at AHG?) would only give a titer of 1:2 (unless your ID is using the newer technologies). To answer your question - you can only explain the data you have discovered. The patient has antibody directed at her own Rh antigens. Maybe you should find out her PCP and give the info to that individual rather than the OB doc. I have not seen autoab only associated with pregnancy. Is she Rh(o)D+? How is the Rh control? If the Rh control is negative, you should have been able to type her without a pretreatment. But this is also a moot point. Not much help to you, but I always find these autoabs very interesting.

comment_9254

I would just tell them exactly the scenario you described and let them evaluate clinically. Perhaps, she should consider not taking the vitamins.

comment_9259

Is this lady Black? If so, you should be looking at some of the more unusual Rh phenotypes that can mimic C and e and can also exist as 'autos'.

Is she shwing any signs of haemolysis? It could be that she's one of these people who just has a benign positive DAT. Any chance of doing the IgG subtype?

Was the previous baby anaemic?? What a lot of questions....Sorry!

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comment_9261

Mom is white. The last baby had no problems with anemia. We use the gel method. We were surprised by titer results also. We had 3+ reactions IgG gel and 4+ reactions on ficin antibody workup. Thanks Mary

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comment_9262

I forgot to add. The autocontrol was negative on our inital antigen typings. We did the chloroquine to double check since we had results not what we expected. Patient is an A positive. I was wondering if something she is being exposed to at work could be causing it. She is not having problems with anemia, no hemolyis. Mary

comment_9268

Most antisera for C and e are not AHG reactors so your auto would be negative. Since you did your ID in gel (and your titer in tubes?) I am not surprised at the difference in reactivitiy. Maybe the antibody is IgG4 subclass, so you would not get hemolysis . . . stuff like this is what makes BB so interesting . . .

comment_9273

I think it maybe because the immune system disorder during pregnancy. Ocassionally healthy blood donor have 3+ IgG DAT and no sign of hemolysis.

comment_9404

I was relieved a few years back when working with an OB with a warm auto to learn that such antibodies, if benign in the mom, are usually benign in the baby. (That's buried in Issitt somewhere.) Although interesting, it sounds like it is a non-problem clinically--expecially with the previous baby being okay.

I wonder if the antibody remained between pregnancies or if it comes back with each pregnancy. Maybe she will volunteer to be checked 6 mo. post-delivery.

Can't antibodies with lower avidity sometimes be partially washed off in the washing phase of tube testing? Since gel is not washed, maybe that helps explain the strength difference--the antibody is lower in avidity.

Hope you don't need to transfuse her. She would be compatible with Ce neg units and you would expose her to Ec pos units by giving compatible units.

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comment_9420

Thanks for all the responses. I plan to ask her at my next appointment for a sample post delivery. Mary

  • 10 months later...
comment_15533

you have to explain to the obg doctor about the pt having warm auto antibodies with the secifities which can cross the placenta and effect the bay like any Rh.HDN ....keep the pt on regular antibody titration monitoring and monitor the fetal function too...i think if the anti body titre falls low it indicates the bay is also psitve for the same antigens thus taking the antibody crossing the placenta....

comment_15542
you have to explain to the obg doctor about the pt having warm auto antibodies with the secifities which can cross the placenta and effect the bay like any Rh.HDN ....keep the pt on regular antibody titration monitoring and monitor the fetal function too...i think if the anti body titre falls low it indicates the bay is also psitve for the same antigens thus taking the antibody crossing the placenta....

I'm sorry irshadaad, but your last sentence is totally incorrect.

If the antibody titre falls during pregnancy, there are two explanations. The first is that the maternal lymphocytes are no longer producing the auto-antibody at the same rate. The other is that the antibody is being adsorbed onto the apical surface of the placenta. The one thing that it is not is the antibody going through the placenta and sensitising the foetal red cells. This would make no difference to the level of the free maternal antibody in the maternal circulation.

Apart from anything else, the maternal antibody, if it is capable of crossing the placenta, is taken over by active transport, and the concentration in the baby is always higher than that found in the maternal circulation, whether or not the foetus is expressing the antigen against which the maternal antibody is directed.

In the UK, we do not perform serial antibody titrations when the maternal antibody is an auto-antibody, and have not done so for years now. At worst, the baby may have a positive DAT at birth, but this is not the same as clinically significant haemolytic disease of the newborn.

:mad:

comment_15574

Thanks, Malcolm.

Say, did the original poster ever get a 6 month post delivery specimen???

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