Jump to content

Patients with blood type A Bel, what to transfuse?


Emelie

Recommended Posts

Hi! We have a patient who genotyped as A Bel. Is the Bel subgroup a complete antigen or partial? The patient expresses extremely low levels of B, would it be safe to transfuse with AB blood? The patient has no detectable anti-B occurring naturally. As far as I can tell by the litterature, Bel cells are not agglutinated with anti-B (but do bind to them)?

We will, of course, have our doctor decide what recommendations to give, but I would like to know how other treat these patients as it´s a first for us.

Please explain it like I´m five :) 

Link to comment
Share on other sites

Putting aside the A antigen for the moment, which is probably "normal" in the case of your patient, it is not the B antigen that is abnormal in the case of a Bel person, but the 3-alpha-galactosyltransferase enzyme (the direct gene product of the ABO gene) is less active than normal, due to a mutation in the gene.  The actual carbohydrate residue that is on the red cell is "normal" - just less of it.  In addition, there is competition between the "A-transferase" and the "B-transferase" for the H-backbone.  In the case of your patient, the "A-transferase" will "win" this competition and this will accentuate the weakening of the B antigen even further - but the actual structure of the B antigen will be the same as the normal B antigen - just fewer in number.  This explains why there is no anti-B present in your patient's circulation.

This (rather long-winded) explanation should serve to prevent you worrying about giving your patient group AB blood should they require a transfusion.

Link to comment
Share on other sites

Thank you! I found it difficult to find general recommendations regarding Bel. I discussed it with our reference lab just now, they weren't convinced about the transferase's ability to produce a complete antigen, since the expression was extremely low. I thought, as you say, that the absence of anti-B would implicate a normal B antigen but they were unwilling to recommend anything but A or 0 blood. This particular patient has a mutation not earlier documented, so it might be their cause for taking extra caution. Thank you for some great insight! It's an amazing forum for gaining new knowledge!

Link to comment
Share on other sites

52 minutes ago, Emelie said:

Thank you! I found it difficult to find general recommendations regarding Bel. I discussed it with our reference lab just now, they weren't convinced about the transferase's ability to produce a complete antigen, since the expression was extremely low. I thought, as you say, that the absence of anti-B would implicate a normal B antigen but they were unwilling to recommend anything but A or 0 blood. This particular patient has a mutation not earlier documented, so it might be their cause for taking extra caution. Thank you for some great insight! It's an amazing forum for gaining new knowledge!

I don't want to interfere, but have you thought about sending a sample to Martin Olsson's laboratory in Lund?  He is the world authority on the ABO gene.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Advertisement

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.