??? AB+ Subgroup with negative anti H

[Desoki]

When I did type and screen for two samples by gel card I found that

Sample 1: antiA +1 antiB +4 antiAB+4 antiD +4 control neg antiA1 neg antiH neg A1cell neg Bcell neg DAT neg antibody screen neg

Sample 2: antiA mixedfield antiB +4 antiAB+4 antiD +4 control neg A1cell neg Bcell neg DAT neg antibody screen neg

No relation between two samples but both are pregnant no history for diseases no history of blood transfusion for 6 months they came only for antenatal checkup.

I confused because of anti H negative so I repeated it with another lot number but the same result was founded.

I guess they are subgroup AB+ but the problem still with this negative anti H.

I want know if I have to do more tests, what is accurate blood group and what group should be taken if they need blood?

[Malcolm Needs ☆]

When I did type and screen for two samples by gel card I found that

Sample 1: antiA +1 antiB +4 antiAB+4 antiD +4 control neg antiA1 neg antiH neg A1cell neg Bcell neg DAT neg antibody screen neg

Sample 2: antiA mixedfield antiB +4 antiAB+4 antiD +4 control neg A1cell neg Bcell neg DAT neg antibody screen neg

No relation between two samples but both are pregnant no history for diseases no history of blood transfusion for 6 months they came only for antenatal checkup.

I confused because of anti H negative so I repeated it with another lot number but the same result was founded.

I guess they are subgroup AB+ but the problem still with this negative anti H.

I want know if I have to do more tests, what is accurate blood group and what group should be taken if they need blood?

I really wouldn't worry about it; this is not an unusual finding with an AB individual.

The H antigen on the red cell is formed by the addition of an L-fucose sugar residue onto the terminal D-galactose molecule, largely on a Type 2 carbohydrate backbone.

This allows the N-acetyl-D-galactosamine sugar residue that forms the A antigen, and the D-galactose sugar residue that forms the B antigen to bind to this (now) sub-terminal D-galactose.

How strong either the A antigen or the B antigen is expressed is determined by which of the two transferase enzymes is the more active (sometimes the A, and sometimes the , and also on the genetically determined isoform of the transferase.

Either way, however, these sugar residues effectively "hide" the H antigen, by steric hinderance, from the anti-H; so much so that, quite often, the H antigen can only be detected by adsorption and elution studies.

These two patients are, from the findings you have given us, group AB, with a possible subgroup of A (but not necessarily - it could be that the B transferase is much more active than the A transferase).

There is, however, no reason why they should not be treated as straightforward group AB individuals for transfusion - and don't worry if they form anti-A1, unless the anti-A1 is shown to react STRICTLY at 37oC.

:D:D:D:D

[LaraT23]

My question is who routinely runs anti-H? That seems odd to me. We also do not routine run Anti-AB anymore, unless we have a discrepancy and are looking for more information. Those two tests being run on the routine typing seem to be wasting time and money. 9 times out of 10 running those without any other issue is not going to tell you anything more. Of those, I would run the AB first with a discrepancy. Just my thoughts on procedure.

Thanks Malcolm for that great explanation.

[Malcolm Needs ☆]

I do entirely agree with you about running an anti-H and an anti-A,b routinely being a waste of time and money. WE run neither routinely, and we are a Reference Laboratory.

Thanks for your kind comment.

[Desoki]

Dear Malcolm and LaraT, I did the anti H and anti AB because I had background about discrepancy in those cases, routinely I don't do anti H or anti AB

[Malcolm Needs ☆]

Ah, sorry; my mistake!

[Yanxia]

msdesoki, it is a very interesting post you give us.

I agree with LaraT and Malcolm that anti-AB is not use in those two case. My reason is that the B antigen is very strong(4+), so the anti-AB will give us 4+ reaction of course. I run anti-AB when the A or B is weaker than normal and the B or A is neg, in this condition I can find the different strength of reaction with anti-AB to detect the Ax and Bx subgroup.

In the two cases you subscribe, I will do the anti-H paralel with two tube of AB adult cells and two tube of B adult cells and two tube of O adult cells. In this test you can get the H antigen express level . But my view is as Malcolm, I don't think this is clinical significant to do the subgroup divid. But if we have time and reagent , it is interesting to do the test and have a look of the subgroup.

Sorry for my English, I hope you can understand my meaning, if not, please tell me and I will do my best to explain it.

[Yanxia]

Perhaps the anti-H we use is different. We have test several AB adult cells they will not give us neg ,but the anti-A1 with A1B group if weaker than with A1 group. If my memory not cheat me, it is 2+ and with A1 cells is 4+.

[rravkin@aol.com]

msdesoki,

In addition to the given posts, I was wondering if any control testing was performed on the Anti-A reagents used for the samples given?