Dosage effect

[Desoki]

Dear colleagues,

Could dosage effect happen with heterozygous panel cells although reactions with other non-dosage cells were ranges between grades 3-4?

[Malcolm Needs ☆]

I'm sorry, it's probably me having brain freeze, but I don't quite understand your question.

Would you mind expanding it a bit?

[Desoki]

I'm sorry, it's probably me having brain freeze, but I don't quite understand your question.

Would you mind expanding it a bit?

Yes Malcolm,

For example when I did 11 cells panel for that patient, the result was reaction grade 3 with cells number three and five (note that cells No. three and five are homozygous for E antigen), this clear for us that, this patient has anti-E, but also I can't rule out anti-JKa because that possibility of dosage effect on cells number six (heterozygous for JKa and JKb leads to negative reaction), and I have no more further investigation available in my work place as selected cells or others.

[Malcolm Needs ☆]

Right. Thanks.

There is NO WAY that I would rule out, in particular, a Kidd antibody with a single cell showing heterozygous expression. Either I would find more cells that are E-, Jk(a+b-), or I would cross-match E-, Jk(a-) blood.

[Desoki]

Right. Thanks.

There is NO WAY that I would rule out, in particular, a Kidd antibody with a single cell showing heterozygous expression. Either I would find more cells that are E-, Jk(a+b-), or I would cross-match E-, Jk(a-) blood.

Dear Malcolm,

This is just virtual example not true case. Because I can't remember exact case, but by that example I can explain my question, again my question is could dosage effect happen with heterozygous panel cells although reactions with other non-dosage cells were ranges between grades 3-4?

[Mabel Adams]

If a second antibody were present it would not necessarily be of the same strength as the antibody reacting 3-4+ so by ruling it out using a single-dose cell, you risk missing a weak antibody that would react only with double-dose cells.

[Malcolm Needs ☆]

Once again, I agree entirely with the wisdom of Mabel.

[catchmenow51]

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Edited December 29, 2013 by catchmenow51

[EDibble]

And, not to add confusion to the mix, if the antibody were just forming, subsequent testing with new samples could show stronger reactivity. There are so many variables involved, it is hard to generalize some of these things.

[Sophie1210]

I agree with everyone else, there are so many variables and you have to consider each system/antigen separately. At my hospital we require 2 homozygous cross outs for Rh, Duffy, Kidd, and MNSs. However, I've told the techs that with M and N, heterozygous cross outs are fine if there are more of those since M and N aren't necessarily clinically significant. K, of course, usually presents a problem because finding K+k- is almost impossible, so I also allow the techs to cross out with heterozygous for that one (we have 62 panel cells at my facility, with the 3 Echo panels and 1 20 cell tube panel, and usually only 1 cell is K+k-).