Advise With Anti-cw Antibodie Detection In Pregnancy Screening Please!!

[kittiikat2000]

Hi

If Anyone Could Help I Would Really Appreciate It.

Pregnant Woman 17 Weeks Gestation, Routine Antenatal Screening Comes Back Immediately With Anti Cw Antibodies Detected And Needs The Patient And Her Partner Re Screened.

How And Why Is This Done And What Could Have Caused It ??

The Patient Is A+ (rh D Pos?? ) We Think!

Any Help Would Be Greatly Appreciated!!

[Dawn]

The patient probably developed the anti-Cw due to exposure to the antigen from a previous pregnancy or transfusion. If the biological father is Cw positive then the baby may be at risk. Currently it is difficult to find commercially available anti-Cw so you may need to send the biological father's sample to a reference laboratory for testing.

Those of us working in reference labs would love to have a sample of this patient's serum/plasma for use in testing other patients. If you have extra sample, please consider sharing it.

[weescot48]

Re: Anti-Cw. I have been told that I require to carry a special card with me at all times, in the event that I have an accident and need a blood transfusion. What is Anti-Cw and what are the implications should I need a blood transfusion. Thanks Janette

[RR1]

Hi Kittikat2000,

I suggest you look at the thread within this section from someone else asking for details on anti-Cw in pregnancy. There is some more excellent information on there too.

[Malcolm Needs ☆]

We have seen an awful lot of cases of anti-Cw in pregnancy in my Reference Laboratory, but we have never come across one that has caused anything more in the way of a clinically significant HDN than requiring phototherapy, BUT....

I do know of this paper:

Kollamparambil TG, Jani BR, Aldouri M, Soe A, Ducker DA. Anti-Cw alloimmunization presenting as hydrops fetalis. Acta Paediatrica 2005; 94: 499-507.

This paper may not be easily obtainable for all, and so I will take the liberty of quoting the Abstract.

"Cw is a low frequency red cell antigen that belongs to the Rh blood group system. While not uncommon, anti-Cw is rarely associated with clinically significant haemolytic disease of the newborn (HDN). When it does occur, it is often subclinical or of mild to moderate clinical severity. In the majority of pregnancies it is considered to be a naturally occuring antibody and has not been reported to cause hydrops fetalis or stillbirth. We report a case of anti-Cw alloimmunization, which was associated with significant anaemia and hydrops fetalis, presenting at 35 wk gestation."

The fact that this warrented a paper suggests just how rare this is!

[weescot48]

Malcolm. Thanks for your reply. I'm not pregnant -Im 61 years old and have just been issued with a card and have been instructed to carry it with me at all times in case I need a blood transfusion. Just out of hospital in last week and nobody told me anything about anti-Cw. I've had two children and its has never cropped up before. How do I suddenly have this "thing" weescot48

[Malcolm Needs ☆]

Hi weescot48,

I'll do my best, but it can be a bit complicated!

Cw is an antigen within the Rh Blood Group System (often, incorrectly, referred to as the Rhesus or rhesus Blood Group System). There are now 50 different antigens recognized within this system. Many of the antigens are either incredibly common (being found in almost everyone in all populations), whilst others are extremely rare (being found in very few individuals within any population).

Many, but all of these antigens have "alternatives" called allelomorphs.

The genes that encode the antigens within the Rh Blood Group System are located on chromosome 1. There are two genes; RHD and RHCE. The bit of the gene that encodes a particular antigen is called a locus. The locus for the gene that governs Cw is found on RHCE.

Unusually, Cw has two "alternatives"; Cx (which is extremely rare) and MAR (which is extremely common).

Cw, or rather anti-Cw was first described as long ago as 1946, when it was recognized in the plasma of a multiply transfused haemophiliac patient in Oxford, England. It is found in about 2% of the White population and 1% of the Black population, but, for some reason is more common in Finland and Latvia.

The antibody (anti-Cw) is quite common; much too common for all of those found to have arisen from either the person being transfused with Cw+ blood, or, in the case of a female, to have carried a Cw+ baby. We call antibodies of this type "naturally occurring", although, to be perfectly honest, this actually means that we haven't a clue what has stimulated the individual to make the antibody!

Anti-Cw is very rarely clinically significant and should cause you no problems whatsoever. The reason that you have been issued with a card is, I would guess, not because you are likely to have a clinically significant transfusion reaction if you were to be transfused with Cw+ blood in the future (you may turn a little jaundiced [yellow], but that is about all), but much more likely because it will help the Blood Bank to identify the antibody quickly, instead of having to go through the whole process of antibody identification without any clues.

Indeed, within the UK, it is now quite unusual for such a card to be issued for anti-Cw.

I hope that this is of some help, but, if not, please do not hesitate to get back and I, or another poster will try to elucidate further.

[weescot48]

Thanks Malcolm. Your explanation has set my mind at rest. Was in hospital with diverticular perforation, but when doing blood analysis, full blood count. LFT's etc, they also discovered my LFT results were as they described "wonky". As a am a retired registered nurse, I asked for an explanation of "wonky", but got little in return. As I only drink alcohol very infrequently (a few glasses of wine every two months or so) I tried to find out what can cause irregularities in the LFT's but to be honest got absolutlely nowhere. I wondered if this was the reason they issued me with a card. I have been having problems even handling a few glasses of wine - it seems to have a very adverse reaction, sometimes making me feel quite ill (sometimes, but not always) Thanks v. much

Janette (weescot48)

[Malcolm Needs ☆]

Glad I could be of help.

I'm sorry I can't help with the LFT's. That's in the Land of Chemical Pathology, which is a land I have never visited (except when I did very basic stuff in my ONC examination several centuries ago)!!!!!!!

[Mabel Adams]

If your liver function tests are "wonky" and drinking alcohol now makes you feel bad, the first thing I would do is skip the alcohol. I would wait till I had recovered a bit from the hospital stay and then ask my doctor to recheck those liver tests and see if they were better, worse or the same. If not essentially normal, I would pin the doctor down to giving me an explanation. He might need to do more tests to figure out the cause. Some drugs can stress the liver and raise the enzyme levels temporarily. Oh, and don't take too much acetaminophen (Tylenol) until your liver gets a clean bill of health or your doctor says it is okay. It is kind of hard on the liver--especially in high doses.

Presenting a card for your anti-Cw means the blood bank would make sure any units transfused to you were compatible with the anti-Cw antibody in your blood. If they don't know it is there, they might miss it in their testing for antibodies to other people's blood because the antigen that the antibody reacts to is so rare and probably won't be present on the cells used to test for antibodies. Since it would be rare in donor units as well, it is unlikely you will be exposed to a Cw positive unit but we would want to make sure.