J Clin Lab Anal. 2018;32:e22288. wileyonlinelibrary.com/journal/jcla
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© 2017 Wiley Periodicals, Inc.
Screening for DEL phenotype in RhD negative Indians
Swati Kulkarni | Disha S. Parchure | Vidya Gopalkrishnan | Manisha Madkaikar
Council for Scientific and Industrial Research
Background: DEL phenotype represents a very weak form of D variant detected only
by adsorption and elution technique. DEL phenotype individuals mistyped as RhD-
niques have now been used to identify DEL variants. They are commonly encountered
in the East Asian population with RHD(K409K) being the most frequent allele.
individuals for two most common DEL mutations.
Material and Methods: EDTA blood was collected from 900 RhD negative individuals.
tube technique. Samples showing negative reaction for the presence of D antigen by
Indirect Antiglobulin test were further tested for DEL phenotype by adsorption and
elutiontechnique. Molecularanalysis involvedDNA extractionand testingby PCR-
SSPforRHD(K409K) and RHD(M295I)DELalleles.
737 with rr phenotype. All the samples tested negative for RhD antigen by adsorption
and elution method. The two common DEL mutations RHD(K409K) and RHD(M295I)
were also not detected in the study population.
Conclusion: The study population showed the absence of the two common DEL
size to look for other DEL mutations should be performed.
1 | INTRODUCTION
The Rh blood group system is one of the most important and com-
plex among the 36 known blood groupsystems.The RhD antigen
is highly immunogenic and has been implicated in transfusion re-
actions and hemolytic disease of the fetus and newborn.
locus consists of the RHD and the RHCE gene. The high degree of
homology and opposite orientation of the two genes favors the pro-
duction of numerous Rh variants. Broadly Rh variants are classified
RhD variants have been documented
to cause allo anti- D immunization in Rh negative patients after trans-
fusion and pregnancy. RhD variants should be identified as they are
clinically important to avoid the risk of immunization. Unlike weak D
the DEL variants are not identified by Indirect Antiglobulin Test (IAT)
and such individuals are typed as D- negative.
primary and secondary immunization of D- negative recipients by
DEL positive units necessitate caution in D negative donors and an-
DEL represents a weakened form of RhD which cannot be de-
tected by conventional serology and requires the use of adsorption
elution technique and hence the earlier name D
antigen density on DEL positive RBCs is very low with number of
D sites ranging from 20- 40 per cell.
DEL phenotype is reported in