Correspondence

Transfusion of RhD-Positive Blood in “Asia Type” DEL Recipients

N Engl J Med 2010; 362:472-473February 4, 2010

Article

To the Editor:

The RhD status of transfusion recipients and donors is routinely matched for red-cell transfusion. This worldwide practice is due to the potent immunogenicity of RhD. In East Asians, the frequency of RhD-negative status is only about 0.3%, which sharply limits the supply of RhD-negative blood. However, approximately 30% of RhD-negative persons carry an RhD variant, termed “Asia type” DEL.1

Beginning in 2008, my colleagues and I organized a collaborative group of 10 laboratories, located in 10 cities in northern, central, and southern China. This group retrospectively evaluated 104 RhD-negative pregnant women with anti-D alloantibodies from 2005 through 2007. We also tracked 199 consecutive RhD-negative pregnant women with a history of gestations or parturitions in 2008. Women who delivered an RhD-negative infant or received Rh immune globulin were excluded from the study. We distinguished Asia type DEL through Rh C, c, E, and e phenotypes and DNA-based polymerase-chain-reaction assays or RHD sequencing.2,3 In our retrospective study, we expected a DEL frequency of 0.30 among 104 pregnant women with documented anti-D alloimmunization. However, none of the 104 women expressed the DEL variant. In the second group, of the 199 RhD-negative women who were prospectively investigated for anti-D alloimmunization, 44 (22.1%) expressed the DEL variant. None of the carriers of this variant had anti-D antibodies, whereas such antibodies were detected in 38 of 155 truly RhD-negative women (24.5%) (relative risk of anti-D alloimmunization, 29.3).

The Asian type DEL displays the complete repertoire of RhD antigen epitopes.4 Our study supports the biochemical observations that the DEL variants express normal RhD and pose virtually no risk of forming anti-RhD antibodies. We suggest that persons in East Asian populations who carry the DEL variants can safely receive transfusions from RhD-positive donors. However, carriers of DEL can still be RhD-negative donors, since there are fewer than 22 membrane RhD antigens per DEL red cell, as compared with thousands of RhD antigens on a normal RhD-positive red cell.4 Our findings can apply to East Asian transfusion recipients in Europe, North America, and elsewhere and could be implemented easily when genetic cross-matching becomes a reality.5

Chao-Peng Shao, M.D.
Shenzhen Blood Center, Shenzhen, China
cpshaos@hotmail.com

Supported by the National Nature Science of Foundation of China (P. 30670893).

Financial and other disclosures provided by the author are available with the full text of this letter at NEJM.org.

This article (10.1056/NEJMc0909552) was updated on March 18, 2010, at NEJM.org.

5 References

1. 1

   Chen JC, Lin TM, Chen YL, Wang YH, Jin YT, Yue CT. RHD 1227A is an important genetic marker for RhD(el) individuals. Am J Clin Pathol 2004;122:193-198
   CrossRef | Web of Science | Medline

2. 2

   Shao CP, Maas JH, Su YQ, Kohler M, Legler TJ. Molecular background of Rh D-positive, D-negative, D(el) and weak D phenotypes in Chinese. Vox Sang 2002;83:156-161
   CrossRef | Web of Science | Medline

3. 3

   Legler TJ, Maas JH, Kohler M, et al. RHD sequencing: a new tool for decision making on transfusion therapy and provision of Rh prophylaxis. Transfus Med 2001;11:383-388
   CrossRef | Web of Science | Medline

4. 4

   Kormoczi GF, Gassner C, Shao CP, Uchikawa M, Legler TJ. A comprehensive analysis of DEL types: partial DEL individuals are prone to anti-D alloimmunization. Transfusion 2005;45:1561-1567
   CrossRef | Web of Science | Medline

5. 5

   Denomme GA, Flegel WA. Applying molecular immunohematology discoveries to standards of practice in blood banks: now is the time. Transfusion 2008;48:2461-75.
   

Citing Articles (2)

Citing Articles

1. 1

   Glenn J. Gardener, Tobias J. Legler, Jonathan A. Hyett, Yew-Wah Liew, Robert L. Flower, Catherine A. Hyland. (2012) Anti-D in pregnant women with the RHD(IVS3+1G>A)-associated DEL phenotype. Transfusionno-no
   CrossRef

2. 2

   Monique Silvy, Sylvie Chapel-Fernandes, Isabelle Callebaut, Sophie Beley, Cécile Durousseau, Sophie Simon, Pierre Lauroua, Nadine Dubosc-Marchenay, Catherine Babault, Chantal Mouchet, Virginie Ferrera, Jacques Chiaroni, Pascal Bailly. (2012) Characterization of novel RHD alleles: relationship between phenotype, genotype, and trimeric architecture. Transfusionno-no
   CrossRef