Anti-D immunization by DEL red blood cells.
BACKGROUND
No data are available on the immunogenicity of extremely weak D variants called DEL. Evaluation of alloanti-D formation in a D- female patient after transfusion of apparently D- blood from an Austrian donor led to discovery of a so far unknown DEL type.


METHODS
Standard blood group serologic methods were applied. Molecular typing, RHD sequencing, and D epitope mapping was performed and the absolute D antigen density determined.


RESULTS
After transfusion of RBCs typed D- by routine serology, the recipient developed alloanti-D. Further evaluation with an indirect antiglobulin test confirmed donor RBCs to be D-. Molecular typing, however, demonstrated the presence of the RHD gene in one donor, and RHD sequencing revealed a deletion of four nucleotides in RHD intron 5 (RHD IVS5-38del4) as the only difference compared to the normal RHD gene. Adsorption-elution techniques demonstrated a DEL phenotype without apparent loss of D epitopes.


CONCLUSIONS
This study documents the clinical significance of the DEL phenotype in blood units that was capable of inducing anti-D in a recipient. Qualitative data are provided on D epitope expression in DEL RBCs.
Wagner
Thomas
T
Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria. thomas.wagner@meduni-graz.at
Körmöczi
Günther F
GF
Buchta
Christoph
C
Vadon
Maria
M
Lanzer
Gerhard
G
Mayr
Wolfgang R
WR
Legler
Tobias J
TJ
D000483:Alleles; D001782:Blood Donors; D001803:Blood Transfusion; D000939:Epitopes / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007438:Introns; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010641:Phenotype; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology*
D000939:Epitopes; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen