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P35
Two Cases of Anti‐D in DAR Individuals
Author(s) -
Lee E.,
Redman M.,
Malde R.
Publication year - 2006
Publication title -
transfusion medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.471
H-Index - 59
eISSN - 1365-3148
pISSN - 0958-7578
DOI - 10.1111/j.1365-3148.2006.00694_35.x
Subject(s) - antibody , medicine , phenotype , epitope , antigen , monoclonal antibody , immunology , gastroenterology , biology , genetics , gene
Current monoclonal anti‐D reagents will react with most D‐variant RBCs. A small number of individuals with D variant phenotypes ( e.g. IIIa, IV, V, VI, VII, DAU) appear to be stimulated to produce allo anti‐D more readily than others. DAR is characterised by the complete loss of at least nine of 37 RhD epitopes. We are reporting two cases of allo anti‐D in patients who have the DAR phenotype. Case history Case 1: An African woman aged 20 was admitted for termination of pregnancy with no clinical history available. She was grouped as B, R o . Her D phenotype using BioVue was weakly positive and also with anti‐D reagents RUM1 and MS201 by tube. The antibody screen was positive, and suggestive of anti‐D. Our laboratory found her RBCs strongly positive with RUM1 and MS201 anti‐Ds by tube and with DiaMed grouping cards. The Diagast D‐screen suggested a weak D antigen. No plasma was supplied for antibody identification. A weak anti‐D by tube LISS IAT was detected in a subsequent sample. The D status was identified by IBGRL as DAR. Case 2: A pregnant African female, aged 35 was grouped by the referring hospital as O, D+; the antibody screen was suggestive of anti‐D by Capture R. Our laboratory had tested her D status in Feb. 2003 after a miscarriage. We reported her as weak D with a negative antibody screen. No anti‐D Ig prophylaxis was given. In our laboratory the most recent sample grouped as O, R o . Her RBCs gave strongly positive reactions with RUM1 and MS201 by tube and with DiaMed grouping cards. The Diagast D‐screen suggested weak D. Anti‐D was detected with a level of <0.1 IU mL −1 . The D status was identified by IBGRL as DAR. Conclusion Immunisation risk for DAR is estimated to be >1% per D+ transfusion, which is less than for anti‐K and anti‐c but similar to anti‐Fy a and anti‐Jk a . The incidence of DAR has been reported as one in 4233 from a population with ‘mixed ethnicity’ in Canada. There is no routine serological method to identify all partial D types. In these two cases the D‐screen indicated both were weak D, and the current monoclonal anti‐D typing reagents used gave positive reactions. Although both of the patients were immunised, the anti‐D in both cases was weak which concurs with our previous experience of anti‐D in partial D individuals. Molecular studies may help to provide further information about the likelihood of the risk of immunisation.