David Saikin Posted August 31, 2016 Share Posted August 31, 2016 Have an 82 yo female, O Neg GI bleed. Presents with a pretty straightforward anti-D EXCEPT some bothersome negative cells. Most cells, R1R1 and R2R2 are 2+ (gel). One R1R1 is absolutely negative, one is very w+. RzR1 is 1+. All other clinically significant antibodies have been ruled out. What am I missing here? Her auto is 1+ in gel, DAT in gel is negative. thanks in advance Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted August 31, 2016 Share Posted August 31, 2016 Well David, I see your problem, but I may be able to suggest an answer. Firstly, the anti-D seems to be quite weak (which is what made me think of my proposed answer). Secondly, of the "common" Rh types, the R2R2 type has the highest number of D antigens per red cell (15 800 to 33 300), and so will tend to give stronger agglutination than will an R1R1 (which may explain why you are getting agglutination with all your R2R2 cells). Thirdly, and turning to the R1R1 red cells, some of these may, of course, be R1r', rather than R1R1, and, therefore, have fewer D antigen sites per red cell (about 9 900 to 14 600, compared with 14 500 to 22 800) and, unless the donor is genotyped, or you can do an informative family study, you may never know (but remember the Cepellini effect). In addition, the number of D antigen sites expressed on a "normal" R1R1 can vary quite a lot from one individual to another (and, indeed, from one cell to another, in the same individual). In other words, those R1R1 red cells that react with your patient's anti-D could be near the "22 800" end of the spectrum, whilst those that do not react with this anti-D may be nearer to the "14 500" end of the spectrum. All figures are taken from Geoff Daniels' book, Human Blood Groups. 3rd edition, 2013, Wiley-Blackwell, page 205. I am not saying for one moment that this is the only, or the most logical explanation, but it is, at least, one explanation! macarton, gagpinks, David Saikin and 5 others 8 Link to comment Share on other sites More sharing options...
David Saikin Posted August 31, 2016 Author Share Posted August 31, 2016 I had thought of most of those; just looking for some support. Malcolm Needs 1 Link to comment Share on other sites More sharing options...
Yanxia Posted September 1, 2016 Share Posted September 1, 2016 enzyme treatment may enhance the Rh system antibodies reaction, maybe it can help Malcolm Needs and David Saikin 2 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted September 1, 2016 Share Posted September 1, 2016 3 hours ago, shily said: enzyme treatment may enhance the Rh system antibodies reaction, maybe it can help Quite right shily, and I should have mentioned that. Yanxia 1 Link to comment Share on other sites More sharing options...
exlimey Posted September 1, 2016 Share Posted September 1, 2016 Could be an (auto) anti-LW, not uncommon in older folks. DTT- or AET-treatment of the test cells might give some insight. Link to comment Share on other sites More sharing options...
David Saikin Posted September 1, 2016 Author Share Posted September 1, 2016 5 hours ago, shily said: enzyme treatment may enhance the Rh system antibodies reaction, maybe it can help if I had it here . . . Malcolm Needs 1 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted September 1, 2016 Share Posted September 1, 2016 4 hours ago, exlimey said: Could be an (auto) anti-LW, not uncommon in older folks. DTT- or AET-treatment of the test cells might give some insight. Could be - but much more likely to be a weak example of anti-D. However David, if you have some group O. rr cord blood available............ David Saikin and exlimey 2 Link to comment Share on other sites More sharing options...
macarton Posted September 2, 2016 Share Posted September 2, 2016 For years, we have run a ficin panel on all of our work ups. Very helpful in enhancing some weak antibodies and those that might be masked by duffy's and MNS systems. Malcolm Needs 1 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted September 2, 2016 Share Posted September 2, 2016 37 minutes ago, macarton said: For years, we have run a ficin panel on all of our work ups. Very helpful in enhancing some weak antibodies and those that might be masked by duffy's and MNS systems. And anti-Ch, anti-Rg and a few others. macarton 1 Link to comment Share on other sites More sharing options...
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