galvania

We got our first one yesterday - antibody panel in gel a uniform weak, but nonetheless clear, reaction with all panel cells, negative auto and DAT (like John's patient). Antibody in tube (ratio 4 to 1 with no LISS) gave moderate reactions with all cells. We DTT treated the red cells and the antibody then disappeared. Exciting. Felt like doing REAL science!

OK - so - I completely misunderstood your post. What you mean is that the patient had anti-B which was detectable for two years then the anti-B disappeared. And the doctor thinks it should still be detectable. Is that right? So what does the rest of the patient's blood group look like? Are there any mixed field reactions? (Would you see them in the technique you are using?) How is the patient's DAT?

:devilish: This sounds like an assignment question to me! Q1 - patient disappeared for 3 years - would his anti-B be present 5 years later? - no because he's probably dead........ :devilish:

I saw a papers about this recently - see below abstract. BACKGROUND: Daratumumab (DARA), a promising novel therapy for multiple myeloma, is an IgG1 monoclonal antibody that recognizes CD38 on myeloma cells. During routine compatibility testing, we observed that the plasma of five of five DARA-treated patients demonstrated a positive antibody screen and panreactivity on red blood cell (RBC) panel testing. We hypothesized that the observed panreactivity reflected DARA binding to CD38 on reagent RBCs, and we investigated methods to prevent this binding. STUDY DESIGN AND METHODS: DARA binding to CD381 or CD38– HL60 cells was assessed by flow cytometry. To remove cell surface CD38, cells were incubated with dithiothreitol (DTT) or trypsin. Soluble CD38 or anti-DARA was used to neutralize DARA in solution. Routine blood bank serologic methods were used to test samples from DARA-treated patients and normal plasma samples spiked with DARA and/or alloantibodies. RESULTS: Normal plasma samples spiked with DARA (0.1-10 mg/mL) and incubated with reagent RBCs recapitulated the interference observed with samples from DARA-treated patients. Flow cytometry experiments confirmed DARA binding to CD381 HL60 cells, but not to CD38– controls. DTT treatment of CD381 HL60 cells reduced DARA binding by 92% by denaturing cell surface CD38. Treating DARA-containing plasma with soluble CD38 or anti-DARA idiotype also inhibited DARA binding. CONCLUSION: DARA causes panreactivity in vitro by binding to CD38 on reagent RBCs. Treating reagent RBCs with DTT is a robust method to negate the DARA interference, enabling the safe provision of blood to DARA-treated patients. Because DTT denatures Kell antigens, K– units are provided to these patients. Resolving the daratumumab interference with blood compatibility testing, Chapuy et al. TRANSFUSION 2015;00;00–00 As to why the patient's DAT and auto were neg, my guess would be that the treatment had already neutralised, maybe even destroyed???? their own CD38, so that their cells are no longer reacting 'normally' in that respect. I don't know. I have no actual experience with this at all.

I 'm sorry but I find it really wierd that the Coombs phase is negative if your saline at 37 is positive. Are you testing in gel or in tube? If the pos reactions rally are due to anti-HLA antibodies I would not worry about red cell transfusion. You might have problems with reduced life span for platelets though

Sorry Quality Guy - I didn't think you sounded rude, and I didn't mean to be either - just to the point! I see SO many cases of gel drying out or supernatant in the reaction chamber because of poor storage or transport conditions... Anna

What elution kit are you using and what type of cards. I would only ever test eluates on IgG cards.

Well quality guy. If you've got 'bad ones' you should be looking into why they're bad - especially if it happens often. It's usually due to disasters during transport or storage in a bad place. Anna

there are three main reasons why this can happen: 1. antibody against a low frequency antigen present on the screening cell but not on the panel 2. Temperature difference between the screen and the panel. Main culprit here is anti-M 3. contamination Are there lots of screens positive with this cell? Yes, all in a batch - cell contaminated No, only this one, but neg on repeat - either 2 or 3 Some - either 1 or 2 You can repeat the panel in IAT (I presume we are talking about an IAT technique here) at RT. If it's an anti-M it will come out more strongly If it's an anti-LFA then finding blood that is XM-compatible won't be a problem

Well I did too - in the old days before gel - and when I was a lot lot lot younger!

I don't know about every time, but I would certainly want to do it after each transfusion

I'll say it again, we just need a quick, clear cut test that tells us who can make anti-D. I don't care what antigen they have or don't have! Well Mabel, if anyone ever comes up with that test, then they will make a fortune. Unfortunately, it doesn't exist - and I doubt if it ever will.....

Or maybe a presentation on the type of mistakes that can be made in the lab, concentrating on mistakes that HAVE been made in your lab (something nice and practical that the lab can relate to easily!)

Even poorer child! Makes me feel very very lucky. So I wonder why he is having these hypertension reactions to CPD-A blood? I wonder if it's the citrate he can't cope with? Have you tried with SAG-M? Anna

That's really helpful. Poor man! I'm amazed he's got to survive this long!! So is his chronic anaemia because he can't manufacture red cells or is it because of his vWD?

Dear Pbach Can you enlighten me about the mitochondrial metabolic syndrome you mention. I'm afraid I have never heard of it Thanks in advance anna

Dear Rapundaa so what you are saying is that she is grouping as a B in the cell group but an AB in the reverse group, even if you use enhanced techniques. Can you tell us something about the patient? How old is she, what is wrong with her? Anna

Well, it is never easy to make a hard and fast rule for all cases. However, thinking back to first principles can help. Anti-D is to avoid at all costs in women of child-bearing age who can still have children (For example, I mean in a 25 year old woman who is having her uterus removed for cancer is of child bearing age, but can't have children). You have finite stocks of D neg blood, and your young women should be the priority. Your second priority should be your patients who are transfusion dependent for life - like sicklers or thalasssaemics. For other chronic transfusions, well, it depends what 'chronic' means, and how much blood you have available and how often the patient needs blood. I would argue that probably for a 90-year old who is not likely to live more than 6 months who needs 2 units of blood every month, you could probably switch to D+ if you needed to without much of a problem. I wouldn't do it on a 40 year old who was receiving blood regularly now but with hopes of remission. Then you have to think that in cases of massive bleeding, the blood doesn't usually stay in the patient long enough for the immune system to 'see' it, so in cases of heavy bleeding it's better to give your D+ first and then switch to D- once the patient is stable. But that's only my opinion.....

Anti-D given 2 months ago and nothing since - if that was a standard dose, I wouldn't really expect it to be still coating her red cells,e ven if she was a partial D - which I would check out if you can - but don't forget that serologically most of the tests are done in IAT and if she's got a pos DAT the results won't be valid. Can you do molecular biology testing? And I would look seriously at this being a strong fetal bleed, with the anti-D being her own anti-D. also, have you got any chance of testing in gel, or even tube? To rule out non-sp with solid phase

Well, auntie-D, I would be very VERY doubtful of the findings in that paper. Firstly, at no time was an eluate carried out. Secondly - neonatal deaths due to anti-M!!!! Unless of course, there are special mutations in the Chinese population. I wonder if they are getting mixed up with anti-'Mia'.....

Is the fact that he is having to receive so many transfusions related to his reactions? Or is he bleeding because of the heparin? Is it not possible to look at the cause of transfusion requirement and try to work on solving the underlying problem, rather than just keep transfusing him with heparinised blood?

My guess would be either (if you are working in gel): The antibody screen was not really positive, just fibrin or some other plasma protein interfering OR A slight difference in method meaning your temperatures were not identical between the panel and the screen OR A different cell buffer screening cells and panel cells (different manufacturer) with an anti-buffer As for the pos DAT, if he hasn't had any blood recently either drug-related or, as Malcolm says, pos for no particular reason....

A paper delivered at the ISBT actually indicated that patients getting older blood fared better than those getting fresh blood

Dear JPCroke no, that's not right, I'm sorry. Most partial Ds and many weak D types have been documented as making anti-D; DVI is just the one most likely to do so amongst Europeans.

Exactly