Antibody Titer After First Affected Pregnancy

[MinerJ]

Hi All,

I was wondering if antibody titre is performed on a pregnant mother who previously had HDFN. According to the books, it mentions 'After the first affected pregnancy, the antibody titer is no longer useful'. Therefore does it mean that it doesn't matter what the antibody titre level is, and should be referred to fetal medicine specialist regardless? Or if there is more to this, I would be grateful for some enlightenment 

[Malcolm Needs ☆]

I may be wrong Jermin, but does this not refer to cases of ABO HDFN, rather than other specificities?

[MinerJ]

Wish I knew, the book did not clarify. I guess its about time I started looking for another source of material.

[Malcolm Needs ☆]

Which book are you using, and at what "stage" are you in your professional life?  The reason I ask is that I may be able to suggest an alternative (but do not want to advise you read the same one! - and I stress an alternative book, rather than a better book; each to their own), and I need to know where you are in your professional life, so that I do not suggest a book that is either too basic, or too advanced.

[MinerJ]

Hi Malcolm

I have been using Rodak’s Haematology. Professionally speaking I am a Band 5 Biomedical Scientist still in course of doing his Specialist (which I may never finish)

*sorry for late reply*

Regards,

Jermin

[Malcolm Needs ☆]

That is no problem whatsoever Jermin.

In no way am I saying that there is anything wrong with Rodak's Haematology; very many people have used this excellent book and passed countless exams, but that does not mean that it is for everyone.  I would suggest, for example, that such "greats" as Geoff Daniels' book Human Blood Groups and "Mollison" are not necessarily everybody's "cup of tea".  In addition, I would suggest that, brilliant as it is, The Blood Group Antigen FactsBook" is not necessarily what you might need.

As a Band 5, may I suggest both Human erythrocyte antigens or blood groups” in Fundamentals of Biomedical Science, Transfusion and Transplantation Science, edited by Robin Knight for the IBMS.  1^st Edition, Oxford University Press 2013 (ISBN 978-0-19-953328-2 (although the second edition is due out in [about] May of this year, and Introduction to Transfusion Science Practice.  Robina Qureshi.  6^th Edition.  2015, British Blood Transfusion Society and, actually, come to think of it, Essential Guide to Blood Groups.  Geoff Daniels and Imelda Bromilow.  3^rd Edition.  2014, Wiley-Blackwell, any oNOTr all of which may be of use to you, and all three of them, give or take the odd chapter, are a very easy read.

The other thing you must do, of course, is go to the BSH website and have a quick scan (NOT a thorough read) of their Guidelines.

Good luck, and do not despair - you WILL finish your Specialist, and you will pass easily, because you have bothered to seek advice; that shows application!  Well done and keep it up.

[MinerJ]

Cheers. I have the  Introduction to Transfusion Science Practice.  Robina Qureshi, and I will seek others when I get the chance.

[SbbPerson ☆]

On 1/23/2018 at 6:24 PM, Jermin said:

Hi All,

I was wondering if antibody titre is performed on a pregnant mother who previously had HDFN. According to the books, it mentions 'After the first affected pregnancy, the antibody titer is no longer useful'. Therefore does it mean that it doesn't matter what the antibody titre level is, and should be referred to fetal medicine specialist regardless? Or if there is more to this, I would be grateful for some enlightenment 

 

After some mothers are sensitized, their titers can be consistently high during subsequent pregnancies. In some case, even when the baby is Rh positive or Rh negative. The titer in this cases would be not helpful for the doctor to develop a treatment plan for the patient. 

 

[L.C.H.]

If the antibody is no longer present in this pregnancy, then so far, so good!  but some antibodies can wax and wane, and if this fetus is positive for an 'offensive' antigen, that antibody may start kicking up again in mom during the pregnancy.  If you know which antibody caused it last time, you can look up and see if it is one that tends to wax and wane. 

Personally, I'd be concerned that the mom you describe could have HDFN again with this current fetus if the fetus has the offending antigen and mom's immune system catches wind of it. I am unclear on the recommendation that titering would only be done with the first pregnancy - our titer levels are what trigger OBs to order Dopplers for fetal anemia, so I don't know how titers could just be passed over simply b/c it's a different pregnancy.  We often see the same woman come back across years with multiple pregnancies, and yes, if we find a clinically significant antibody, we do start chasing titers, regardless of whether she has ad the antibody in the past. 

[SbbPerson ☆]

22 hours ago, L.C.H. said:

If the antibody is no longer present in this pregnancy, then so far, so good!  but some antibodies can wax and wane, and if this fetus is positive for an 'offensive' antigen, that antibody may start kicking up again in mom during the pregnancy.  If you know which antibody caused it last time, you can look up and see if it is one that tends to wax and wane. 

Personally, I'd be concerned that the mom you describe could have HDFN again with this current fetus if the fetus has the offending antigen and mom's immune system catches wind of it. I am unclear on the recommendation that titering would only be done with the first pregnancy - our titer levels are what trigger OBs to order Dopplers for fetal anemia, so I don't know how titers could just be passed over simply b/c it's a different pregnancy.  We often see the same woman come back across years with multiple pregnancies, and yes, if we find a clinically significant antibody, we do start chasing titers, regardless of whether she has ad the antibody in the past. 

 

Some mother titers remain high during subsequent pregnancies. Clinical information from the titers would then be misleading. This is why doctors don't order titers on moms who has been sensitized from the first pregnancies. 

 

[Malcolm Needs ☆]

3 hours ago, diplomatic_scarf said:

Some mother titers remain high during subsequent pregnancies. Clinical information from the titers would then be misleading. This is why doctors don't order titers on moms who has been sensitized from the first pregnancies. 

 

That is true, but then they need to follow the pregnancy by other means, such as ultrasound and/or mid-cerebral artery Doppler measurements are performed to ensure the health, or otherwise of the foetus is followed.

[SbbPerson ☆]

22 minutes ago, Malcolm Needs said:

That is true, but then they need to follow the pregnancy by other means, such as ultrasound and/or mid-cerebral artery Doppler measurements are performed to ensure the health, or otherwise of the foetus is followed.

 

Yes, I am sure they probably order those other tests you mention. But the topic of this thread is on "why titers are not ordered on subsequent pregnancies". 

[Malcolm Needs ☆]

Oh, silly me.  I was too stupid to notice that.  Thank you for putting me back on the straight and narrow.

[mrmic]

It is all relative.  Yes, antibodies' titers can rise and fall during pregancy whether or not the fetus is positive for the corresponding antigen(s).  So titers may not be helpful in a subsequent pregnancy from a mother whom has shown to be an immune responder.  But, it may be a one piece of the puzzle a physician can use to make decisions about the management of the pregnancy.  It may be an opportunity for us  to be part of the team, share our knowledge and experiences with the team, follow the immunohematology path, maybe learn something ourselves and share with our peers.  I would be willing to follow the titers, it's Immunohematology, it's what we do, and maybe, just maybe, we might discover something relative.  My soapbox for the day, just comments from my perspective as an old retired SBB.

[Malcolm Needs ☆]

24 minutes ago, mrmic said:

It is all relative.  Yes, antibodies' titers can rise and fall during pregancy whether or not the fetus is positive for the corresponding antigen(s).  So titers may not be helpful in a subsequent pregnancy from a mother whom has shown to be an immune responder.  But, it may be a one piece of the puzzle a physician can use to make decisions about the management of the pregnancy.  It may be an opportunity for us  to be part of the team, share our knowledge and experiences with the team, follow the immunohematology path, maybe learn something ourselves and share with our peers.  I would be willing to follow the titers, it's Immunohematology, it's what we do, and maybe, just maybe, we might discover something relative.  My soapbox for the day, just comments from my perspective as an old retired SBB.

Yes, this was more or less along the lines of the UK Guidelines on the subject (see British Committee for Standards in Haematology (BCSH): White J, Qureshi H, Massey E, Needs M, Byrne G, Daniels G, Allard S.  Guidelines for blood grouping and red cell antibody testing in pregnancy.  Transfusion Medicine 2016; 26: 246-263 [doi: 10:1111/tme.12299]).

[RichU]

I always understood it was the change (especially upwards trend) in titre throughout pregnancy which indicated whether there might be a problem for the current fetus (and likely antigen status) rather than just a historic or latest result.

A change of titre from 2 to 32 is more alarming than a titre which is 32 at booking but remains at 32.

[Malcolm Needs ☆]

2 hours ago, RichU said:

I always understood it was the change (especially upwards trend) in titre throughout pregnancy which indicated whether there might be a problem for the current fetus (and likely antigen status) rather than just a historic or latest result.

A change of titre from 2 to 32 is more alarming than a titre which is 32 at booking but remains at 32.

Most certainly a big rise is a worry, but a titre that remains at 32 is also a worry (see the Guidelines I cited above).  If you don't believe them, try the Royal College of Obstetricians and Gynaecologists (RCOG).  The management of women with red cell antibodies during pregnancy.  Green-top Guidelines No.65; May 2014.  https://www.rcog.org.uk/globalassets/documents/guidelines/rbc_gtg65.pdf.  Essentially, they say the same thing.  I am, I must admit, somewhat surprised, given your own professional history, and the fact that you work in the Isle of Man, which is covered by both sets of Guidelines, that you think that way.

[RichU]

21 hours ago, Malcolm Needs said:

Most certainly a big rise is a worry, but a titre that remains at 32 is also a worry (see the Guidelines I cited above).  If you don't believe them, try the Royal College of Obstetricians and Gynaecologists (RCOG).  The management of women with red cell antibodies during pregnancy.  Green-top Guidelines No.65; May 2014.  https://www.rcog.org.uk/globalassets/documents/guidelines/rbc_gtg65.pdf.  Essentially, they say the same thing.  I am, I must admit, somewhat surprised, given your own professional history, and the fact that you work in the Isle of Man, which is covered by both sets of Guidelines, that you think that way.

Sorry, it's not that I don't recognise the significance of a titre of 32, just that I wished to illustrate that a rising titre is significant during any pregnancy but if you don't do any titrations, due to detecting an antibody in a previous pregnancy, how would you pick it up?

[Malcolm Needs ☆]

1 hour ago, RichU said:

Sorry, it's not that I don't recognise the significance of a titre of 32, just that I wished to illustrate that a rising titre is significant during any pregnancy but if you don't do any titrations, due to detecting an antibody in a previous pregnancy, how would you pick it up?

Ah, there I totally agree (except for antibodies related to antigens within the Kell Blood Group System - again, see the Guidelines).

[RichU]

There's always a caveat with serology! Sometimes when things are so ingrained it's easy to take them as read.