patient with anti-Kell and something else that appears to be more strongly expressed in a D positive background

[BrianD]

i've spent the evening working on a patient demonstrating an anti-Kell antibody. she is O positive, with a negative autocontrol and negative DAT. she also has a cold auto-agglutinin but it isn't very strong. 2 of 5 Kell negative O positive units were IAT-XM incompatible. expanded Ab I.D. panels (D pos and D neg) were tested and we still haven't resolved what this other ab is. in the D negative panel, the reactions of the Kell negative "positives" are much weaker than those demonstrated by the D positive Kell negative cells. (+/- "equivocal" vs. 3+). the transfusion service manager has not approved further work up since we've 3 IAT-XM compatible Kell negative units available and the patient isn't likely to need transfusing. any thoughts of what this other ab could be would be greatly appreciated...i need the ammo in my campaign to gently encourage reconsideration of having this worked up, further.

b.

[Mabel Adams]

I assume you have been able to cross out all of the usual suspects on the panel sheet? Once you have done that for every specificity for which commercial antisera exists, you are probably going to be giving crossmatch compatible blood anyway, so knowing what the specificity is may not make any difference. Still with weak reactions you need to make sure you have not missed anything important. Sometimes it is easier to figure out what it is, even if not significant, so you know what it isn't. If you can rule the usual specificities out with a homozygous cell (and at least 2 homozygous cells for Jka) then look at M showing dosage, extended antigen typings of your panel cell (look for Bg types particularly), think about HTLA-like antibodies and possibly repeat some tests with increased sensitivity (like incubate 30 minutes instead of 15) to see if they get stronger. Your boss has a point; if you are not going to do anything different to find compatible blood even after you do a bunch more workup, then there is not much point in doing it. I wasn't clear whether you wanted to send it out or do more yourself. It also makes some small difference if you are testing in gel or tube or solid phase which I didn't notice that you mentioned.

[BrianD]

hi Mabel. the usual suspects are ruled-out. the patient's ab (other than Kell) seems better demonstrated by tube-testing using PEG or by CAT. by the SPRCA/LISS, the reactions are not quite so definite. i'd prefer to complete the work up in-house but we are "managed" now and pre-approval for absorptions, elutions, enzyme panels, etc. is required. this reaction pattern reminds me of something i saw when i worked at an IRL years ago but i cannot recall the identification.....i've found as i've gotten older that i remember less and less. since the patient has been able to "take-down" 2 of 5 appropriately selected donors, i feel it would be a good idea to know what we're dealing with.....these were definitel 3+/4+ incompatible reactions. i admit that it's a bit irrational, but i feel like the job's not half-done.

b.

Edited May 12, 2012 by BrianD

[Malcolm Needs ☆]

Possibly an auto-anti-LW?

[Mabel Adams]

Wouldn't all of the Rh pos units have looked incompatible with an anti-LW? I thought it tagged along with D antigens.

Is your reactivity rate in the range of 60-80%? If so, there's always Dombrock. I keep waiting to find one sometime in my career.

[Malcolm Needs ☆]

Yes, you would think they would, but the number of antigen sites per red cells means that this is not always the case.

Good luck finding a Dombrock antibody. Weak, wishy-washy little Devils that can cause major transfusion reactions on rare occasions.

[Eagle Eye]

I agree with you that you want to complete the workup. If you have 3+ or 4+ incompatibility...yes I would want to complete the workup...If you want to do additional workup inhouse, why is it a big deal...

[BrianD]

Possibly an auto-anti-LW?

i was thinking perhaps something along this line, Malcolm. isn't anti-LW(a) the same as anti-Bigelow....that's what i remember from a similar case at an IRL years ago. not convinced it's an auto ab since her DAT by both CAT and SPRCA methods are negative but it just might be some cold agglutinin stickiness but i'm not convinced of THAT because our IAT-XM reagents are anti-IgG. The patient has received 2 of the XM compatible units and has "pinked up" nicely. she'll most likely go home in the a.m.

[BrianD]

Is your reactivity rate in the range of 60-80%? If so, there's always Dombrock. I keep waiting to find one sometime in my career.

of "appropriately selected" [i.e., O positive Kell negative] donors for the IAT-XM, roughly 40% of the donors are incompatible

[Malcolm Needs ☆]

i was thinking perhaps something along this line, Malcolm. isn't anti-LW(a) the same as anti-Bigelow....that's what i remember from a similar case at an IRL years ago. not convinced it's an auto ab since her DAT by both CAT and SPRCA methods are negative but it just might be some cold agglutinin stickiness but i'm not convinced of THAT because our IAT-XM reagents are anti-IgG. The patient has received 2 of the XM compatible units and has "pinked up" nicely. she'll most likely go home in the a.m.

Not quite BrianD; anti-Bigelow was anti-LWab.

The reason that I say auto, even though the patient's auto and DAT are both negative, is because it is mcu more common for people to become transiently negative for the LW antigen(s) and make an apparent allo, but in reality, auto-anti-LW, than for them to be genuinely LW-.

[BrianD]

Not quite BrianD; anti-Bigelow was anti-LWab.

it is much more common for people to become transiently negative for the LW antigen(s) and make an apparent allo, but in reality, auto-anti-LW, than for them to be genuinely LW-.

her retic# isn't elevated so if she's leaking it's a slow leak and her chemistries suggest iron deficiency and protein malnutrition, could these lead to a depression of LW ag expression?

[Malcolm Needs ☆]

Hmmmm, not that I know of. It's usually due to an infection, from what I can remember.

[Yanxia]

I think this is like anti-LW, it is looks like anti-D, because LW antigen is more on D pos cells than D neg cells.

Anti-LWa and anti-LWab will be mis-identified as anti-D, anti-LWb is rare, so the interfer is not so common.