Bet'naSBB Posted November 14, 2022 Share Posted November 14, 2022 We have an Rh neg patient who has received 4 units of Rh neg RBC's and has made what looks to be a perfect anti-D. We do not have a pre-transfusion sample - so the C typing is mixed field (in gel- not strong......more negative cells at the bottom of the column compared to positive cells at the top - like you might imagine in a patient who is C neg and received 1 unit of C pos blood......) leaving us to wonder if they're C pos or C neg..... We typed the 4 units they received and one is C pos. We "want" to say this is an anti-G - but, there's absolutely NO anti-C reactivity. Not even with enzymes. DAT is negative. We've also scoured the few lit. resources we have and none of them address that an anti-G could / would do this..... We even repeated the weak D's on the units...........all tested weak D neg. Any insight?? Side note: We've checked about IVIG, other drugs - nothing. They did get 2 units of A pos FP24 - but that, IMHO - shouldn't have caused any of this. @Malcolm Needs?? Link to comment Share on other sites More sharing options...
exlimey Posted November 14, 2022 Share Posted November 14, 2022 1 hour ago, Bet'naSBB said: We "want" to say this is an anti-G - but, there's absolutely NO anti-C reactivity. Reading between the lines, I believe you're saying that C+D- (r'r) panel cells are nonreactive, thereby excluding the presence of anti-C, If that's the case, and since said cells should carry the G antigen, it is very unlikely you're dealing with anti-G. Anti-LW may mimic an anti-D pattern by demonstrating reactivity only with D+ cells. It's also very remotely possible that one of the donors carries a rare form of D-antigen that is not readily detected by typical commercial reagents. However, those are very rare and their ability to stimulate an immune response is not well understood. Ensis01, AMcCord, Malcolm Needs and 2 others 5 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted November 14, 2022 Share Posted November 14, 2022 I agree ENTIRELY with the answer given by exlimey. Anti-G usually (not always, but usually) reacts more strongly with the C antigen than the D antigen, so that R1R1 and r'r red cells would give stronger reactions than would R2R2, whereas both anti-D and anti-LW would react more strongly with R2R2 red cells than R1R1 and r'r red cells. I agree that one of the units could express an unusual D type (I was caught out once in a pregnancy case when the dad had the unusual D type of RHD(L214F)-CE(7)-D - which I thought was rather unfair of him!). Have you tried rr cord bloods against the patient's plasma/serum sample? The LW antigen is expressed much more strongly on cord red cells than adult red cells. exlimey, AMcCord, Ensis01 and 1 other 4 Link to comment Share on other sites More sharing options...
Bet'naSBB Posted November 14, 2022 Author Share Posted November 14, 2022 This morning we tested with DTT treated screening cells - reactivity was still there. If it had been an Lw - it should have been negative..... exlimey and Ensis01 2 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted November 14, 2022 Share Posted November 14, 2022 Suggests to me that this really is an anti-D then. I'll keep thinking (or trying to think at my age!). Ensis01, John C. Staley, Bet'naSBB and 1 other 4 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted November 16, 2022 Share Posted November 16, 2022 I've been wracking my brains over this one, but I have hit a brick wall. If it is not an anti-LW, I can see no alternative to an anti-D (possibly caused by a previous pregnancy - if the patient is female [or, these days, possibly a transexual who is now a male], or by one of the donors having a very rare RHD mutation). Somebody will now come up with an explanation that is quite simple, and I really should have thought of immediately!!!!!!!!!!! Link to comment Share on other sites More sharing options...
RRay Posted November 16, 2022 Share Posted November 16, 2022 I've had this come up before with incomplete transfusion history (transfusions at another facility) and with IV drug use / sharing needles. Occam's razor? Malcolm Needs, Ensis01 and exlimey 3 Link to comment Share on other sites More sharing options...
exlimey Posted November 17, 2022 Share Posted November 17, 2022 I was also thinking of a prior sensitization. A weird, barely detectable D+ phenotype may not generate a new immune response, but may be enough to reactivate the primed lymphocytes in an individual who's anti-D has faded into non-detectability. Tiny re-exposure and wham ! Nice, strong, clear-cut anti-D, apparently out of nowhere. Ensis01 1 Link to comment Share on other sites More sharing options...
exlimey Posted November 17, 2022 Share Posted November 17, 2022 16 hours ago, RRay said: I've had this come up before with incomplete transfusion history (transfusions at another facility) and with IV drug use / sharing needles. Occam's razor? Agreed....history is always a wildcard. I had a case once where there a teenaged male individual had antibodies to red cells (I can't remember the specificity) with no apparent transfusion history. Later questioning revealed that the person was part of a "Blood Brothers" group who routinely and ritually exchanged blood through self-inflicted cuts. Each to their own. Bet'naSBB 1 Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted November 17, 2022 Share Posted November 17, 2022 48 minutes ago, exlimey said: Agreed....history is always a wildcard. I had a case once where there a teenaged male individual had antibodies to red cells (I can't remember the specificity) with no apparent transfusion history. Later questioning revealed that the person was part of a "Blood Brothers" group who routinely and ritually exchanged blood through self-inflicted cuts. Each to their own. VERY good point. When I was working at Westminster Hospital (many, many moons ago now), we came across a male Jehovah's Witness patient who swore blind that he had never been transfused, with one of the strongest polyclonal human-derived Fya antibodies I have ever seen. Bet'naSBB, exlimey and BldBnker 3 Link to comment Share on other sites More sharing options...
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