Is there such a high titer high avidity?

[pharez]

If there's a high titer low avidity (HTLA) like antibody is there such a high titer high avidity antibody like reactivity? The patient is 50 year old  male with a hemoglobin of 7. Anti-S (alloantibody) was identified on his sample during his first hospital visit 2 months ago and 2 units were transfused that time uneventfully. When he came back, all cells on the panel including the S negative cells were 2+ positive with his serum except the autocontrol. Polyspecific DAT was still negative like the first time. The second antibody panel had 3 cells negative that ruled out the possible antibodies to common antigens he could make. The rest were all 2+ positive. So that is neither an antibody to high incidence antigen nor multiple alloantibodies. Alloadsorption, 0.2M DTT and ficin didn't all work and titer was 2+ from undiluted serum to tube 8, then 1+ up to 512 and weakly positive up to the end-2048. This is high titer high avidity and not high titer low avidity.Has anybody encountered this kind of workup? How did you deal with it? Thanks a million folds.

 

[David Saikin]

Sounds like you sensitized this person to something besides S. You will need to figure it out or send to a reference lab. The titer is probably high because it is fairly new and remains from its generation following the 2u transfusion. Did you Rh phenotype the pt? I know it is less than 3 months but chances are all the transfused cells are gone (due to your pt's new ab)? It is worth a shot, you can ignore any mixed field typings. Are you able to run a different ab panel, or do you only have one? Is your testing in tubes, gel, solid phase?

Titering a sensitizing event seems like a lot of work with limited clinical value (to me).

Good luck!

Edited January 23, 2014 by David Saikin

[pharez]

Thank you David. We just sent it to a reference lab.

[R1R2]

Thank you David. We just sent it to a reference lab.

keep us posted

[jill]

Are your panels tested in tube or solid phase? 

 

If in tube, there's a possibility that this antibody may have formed against a constituent in your reagent cells

based on the fact that all other allos are ruled out and you are seeing are seeing strong reactions with no pattern.

 

I have seen these antibodies titer high.

 

Try testing panels with washed reagent cells to see if it gets rid of the reactivity.