? Antibody Specificity in Pregnancy ?

[Malcolm Needs ☆]

Rashmi (RR1) has told me that I should put some of our cases on BBT and, as other posters know, I always do what she tells me.

I am waiting for a sample to come in to owrk on on-call, and so here goes with one.

In January this year, we received a sample of blood from a 32-year-old pregnant lady.

We found her to be group A, R1R2, Cw-, M- N+ S- s+ P1+ Lu(a-b+) K- k+ Kp(a-b+) Le(a-b+) Fy(a+b+) Jk(a+b-).

The DAT was negative.

The antibody reacted with 5 of 10 panel cells by DiaMed gel papain technique (range 3+ to 5+) and with 10 of 23 panel cells by DiaMed gel IAT (range of 1+ to 3+). The antibody did not pattern for any antibody directed against one of the major blood group antigens.

The antibody did not pattern as an "HTLA", having a titre of 4 and was not inhibited by AB plasma.

A second sample (sent in 4 months later!) reacted with 7 of 10 panel cells by DiaMed gel papain technique (all 4+) and with 6 of 10 panel cells by DiaMed gel IAT (range 2+ to 3+) and also by LISS tube IAT at strictly 37oC (range 1+ to 2+).

This was all we knew, but managed to "guess" the correct specificity prior to sending the sample to the International Blood Group Reference Laboratory.

What is the likely specificity?

Two clues are that the antibody usually gets weaker, rather than stronger, but has been implicated in transfusion reactions.

Good luck (we needed it)!

:):)

[L106]

I have a not-so-bright question, Malcolm.

When you say that the antibody reacted "also by LISS tube IAT at strictly 37oC (range 1+ to 2+)", do you mean that:

1. the antibody reacted in the Antiglobulin phase only after it had been incubated at 37 C, OR do you mean that:

2. the antibody reacted when you centrifuged the tube after 37 C incubation (ie: prior to the addition of Antiglobulin reagent)?

[Malcolm Needs ☆]

I have a not-so-bright question, Malcolm.

When you say that the antibody reacted "also by LISS tube IAT at strictly 37oC (range 1+ to 2+)", do you mean that:

1. the antibody reacted in the Antiglobulin phase only after it had been incubated at 37 C, OR do you mean that:

2. the antibody reacted when you centrifuged the tube after 37 C incubation (ie: prior to the addition of Antiglobulin reagent)?

It is far from a not-so-bright question; it's my fault for not making it clearer.

What I mean is the first of your choices. It worked by LISS tube IAt at 37oC (not by direct agglutination at 37oC), as well as by DiaMed gel IAT. In other words, it was a genuine 37oC IgG antibody, rather than a "cold" antibody (like an anti-M) that works in DiaMed gel IAT because of mixing at room temperature before incubation, but not by a LISS tube IAT at strict 37oC.

Sorry about the confusion.

:redface:

[YorkshireExile]

Malcolm,

Any chance of attaching the actual panel sheet results so we could take a look?? Or would that not help in working out the specificity in this case?

[Malcolm Needs ☆]

Malcolm,

Any chance of attaching the actual panel sheet results so we could take a look?? Or would that not help in working out the specificity in this case?

I'm sorry. I can't.

It would not help you in the least, however, which may give you a clue that it is not anti-D, -C, -c, -E, -e, -Cw, -M, -N, -S, -s, -P1, -Lua, -Lub, -K, -k, -Kpa, -Kpb, -Lea, -Leb, -Fya, -Fyb, -Jka or -Jkb!!!!!!!!!!!!!!!!!!!!

It does still leave you with quite a wide choice!

Oh, and it's not an ABO antibody.

[David Saikin]

Might it be an antibody to a compound ag in the Rh system?

[Malcolm Needs ☆]

No, sorry David.

I will say that it is a monospecific antibody, rather than a mixture, but it is not an Rh compound antibody.

[SMW]

Dombrock?

[David Saikin]

Anti-Doa

Edited September 28, 2009 by David Saikin
incorrect attribute

[L106]

Oooooo....You guys are good!!!

[David Saikin]

Good, ok, but are we correct?

[Malcolm Needs ☆]

Sorry, I've been away at a Congress for a couple of days, and so have been unable to answer.

Quite correct; the answer is anti-Doa!

Well done indeed! I am very impressed.

For those members less familiar with this antibody, it is unusual to find this antibody as a single specificity, it is notorious for becoming weakened quickly and disappearing altogether, has not been known to cause clinically significant HDN (just a positive DAT), but has been implicated in clinically significant transfusion reactions.

Decent, grouping anti-Doa is as rare as hen's teeth (and this wasn't one either!) and so we send most of our samples requiring such typing (including donor samples) to the International Blood Group Reference Laboratory for molecular work.

:judge::judge::judge::judge::judge:

[L106]

To SMW & David Saikin -

See, I knew you guys were good.! (And correct!!!)

[Malcolm Needs ☆]

To SMW & David Saikin -

See, I knew you guys were good.! (And correct!!!)

Couldn't agree more with you.

:D:D:D:D