We had a patient this week that was in a couple of years ago. At that time, She had a remote transfusion a couple of years prior, then she had been transfused about 7 units about 3-4 months prior, and then 2 units only about a week before. We found a 2+ DAT (IgG), reactivity resembling anti-D in gel (she is O pos) and an eluate with a panagglutinin. (I find that a lot of autoantibodies in gel prefer D pos cells.) The place that transfused her just prior had found similar results and had antigen typed her pretty extensively and gave her D neg units. She is negative for K, C and Jkb.

Now she has a negative DAT in tube (still weakly pos Auto control in gel) and her screen is postive. ID showed reactivity only with 3 Colton B pos cells and one other cell besides the screen cell (which has not been tested for Cob). All the usual suspects could be ruled out with multiple double-dose cells. Has anyone ever seen an anti-Colton B by itself (well, with another Ab to a low-freq). I'm sure it is possible--especially if a screen cell is Cob pos so you can find it.

Here's what my fertile mind is stewing on: what if she made an anti-Jkb plus the currently detectable antibodies, but its titer dropped too low to detect. I can't really quite make a case for giving her Jkb- units on this basis, but I would appreciate knowing other's more extensive experience with such cases.

She came through surgery okay and is unlikely to be transfused during this visit.

I have seen 2 patients who apparently have anti-Cob alone and 2 patients with anti-Cob + one other alloantibody. (Three of them were first ID'd all in one week! How lucky can you get?)

One of the solo anti-Cob patients had been recently transfused by us, his first transfusion ever. When we ID'd the Cob, the timing from that first transfusion was such that I would have expected to see anti-E or an anti-JK if he had made one of those also. The other solo case was a multiparous woman who though she "might" have been transfused elsewhere in the distant past but she was not a good historian, so we didn't attempt to track anything down. We ID'd the anti-Cob only, transfused her several times over the next few months and never saw evidence of any other alloantibodies. Of course, both of these folks could have had antibodies to low incidence antigens that we never saw.

Guess those 2 antibodies forgot to read the book that said they were supposed to come with friends.

Hi Mabel!

We have had 2 cases of Co b alone and 2 of with. Oddly enough our 2 alones came in a one week period as well. One was a donor sample and another was a work-up from a small hospital that had a neg. Ab screen and one reactive unit at crossmatch. Both were only found after we "converted" 3-5% immucor panel 16s to .8%. We do this almost everyday to use the extended typing.

We just identified a Colton b yeterday on a patient with a previous Anti-S, and probably Anti-Kell. She received one unit yesterday with no issues, but on the second unit she had a drop in BP. No other symptoms and her DAT is negative pre and post transfusion.

Any other issues to be looking for? This is a new one to me.

thanks,

John

Another quick note about the Colton b. If this patient had not had an Anti-Kell this may have gone unnoticed. The screening cells are all negative for the Cob antigen. I checked with ARC Reference lab and about 8% of the population is Cob antigen positive. Coa antigen is prevelant in about 99.8% of the population according to ARC and AABB. Anyway, ARC suggested crossmatch compatible only as they only had unlicensed typing sera.

John

I would go for cross-match compatible too.

Thanks Malcom,

That is what we did and with the exception of the one incident of a drop in BP the patient received 3 units and had no other issues.

I appreciate your input!

John

Hi Malcom,

I know this may be unusual, but I just identified a second Anti-Cob in a patient with no history of receiving blood - at least at our facility. No other antibodies were identified. Crossmatch compatible units were transfused and no issues were identified. According to the literature I find, 92% of all units should be crossmatch compatible and there is no Cob typing sera available.

Thanks,

John

Hi John,

It is quite rare to find anti-Cob as a single specificity; to find two in such a short space of time is positively greedy!!!!!!!!

I have no information on "naturally-occurring" anti-Cob (it wasn't a lady who had been pregnant in the past, was it?), but I think that this must be even rarer.

You are correct about Co(b+) being about 8% of the population.

Nice one!

Hi Malcolm,

Trust me, I am beginning to think we have "spirits". In the last 5 weeks we have had 2 stat alone Anti-Coa antibodies and a Lua antibody.

We have recently switched to the Tango automated BBK system and really enjoy it. It has been a very nice addition.

I don't mean to be greedy, just one of those time when the moon is in the wrong position - or right position - whichever way you want to see it!

Thanks,

John

The only Anti-Cob we identified was also present with 3 or 4 other alloantibodies.

Hi Malcolm,

Trust me, I am beginning to think we have "spirits". In the last 5 weeks we have had 2 stat alone Anti-Coa antibodies and a Lua antibody.

We have recently switched to the Tango automated BBK system and really enjoy it. It has been a very nice addition.

I don't mean to be greedy, just one of those time when the moon is in the wrong position - or right position - whichever way you want to see it!

Thanks,

John

John,

Did I read that correctly; two cases of anti-Coa? Even one of those is REALLY rare.

Malcolm

:wow::wow:

Hi Malcolm,

Yes, we have had two! I have done this type of work for 42 years and this is a first for me. We sometimes see a lot of antibodies that are "unusual" for the general population as I live is a tourist/ resort community. We have a lot of people that have moved here for retirement and sometimes we see some pretty strange stuff!

I think our demographics is somewhat skewed because of the retirememt, vacation location.

Yes, you did read that correctly! Your eye did not fail you. I thought mine did, but it turned out to be two Coa antibodies on two seperate patients.

It is one of those things that make this occupation interesting. You just never know what the next patient sample and/or phone call will bring you. It is the same, but different everyday.

Regards,

John

Thanks for that John (and congratulations!).

By absolute coincidence, we had a sample in yesterday on a lady who had previously had an anti-E, and has now also developed an anti-Coa!!!!!!

They're getting as common as muck aren't they???????????????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Yes they are!

Congratulations to you too!

I still remember my first antibody when I started. It was my first night working by myself and I have a lady that turned out to be an A2B with an anti-A1. We had four AB units on inventory and 2 of the 4 were A subgroups, compatible and given with no problems.

Sometime things just go your way.

Have a good day.

John

Being as old and decrepit as I am, I can't now remember my first ever antibody, but, I started out in my professional life as a very green Technician at the International Blood Group Reference Laboratory (when it was in London) working under Dr. Carolyn Giles and Joyce Poole. This was the time when Dr. Bertil cedegrin was doind a study of Vel negatives in Upsala (not sure that is how to spell it!) in Sweden, and we regularly received samples to confirm that they were Vel-, with or without anti-Vel.

For a very long time, I was under the mistaken impression that anti-Vel was more common than anti-D, because, of course, all anti-D's were confirmed either by the Hospital Blood Banks or by the Regional Transfusion Centre's Reference Laboratories, and so such common antibodies never reached the rarified Laboratory in which I was working!

I should be careful about what I think is true, and take into account where I work - something I have never learned!!!!!!!!!!!!!!!!!

:giggle::giggle:

I could be considered to be somewhat old and decrepit, but I remember my first antibody (and the patient's name.) It was an Anti-Jka in a lady who had been transfused a couple weeks earlier and was now quite jaundiced and anemic. Classical case! She recovered and did OK (partially thanks to the Jka Negative donor units I provided!!)

Donna

Sometimes I wish I had kept a running diary of the things I have seen over 42 years. One thing for sure, you never know what the next sample or phone call will bring you!