الفهرس 
Introduction
The ABO & H blood group systemsOnly 14 pages are availabe for public view
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Abstract
The D antigen is present on red cells of 85% of white people and is more frequent in African and Asian population (Daniels G 2013), D antigen (ISBT 004.001; RH1) is the most immunogenic and clinically important of this system because of the ability of anti-D to cause transfusion reactions and hemolytic disease of the foetus and newborn (Kabiri et al., 2014). RhD variants are classified for clinical purposes into one of three groups: partial D, weak D, and DEL, which are defined as D antigen or proteins, partial D lack D antigen epitopes, and individuals with these types have the potential to develop alloanti-D, whereas weak D generally present all D epitopes and does not pose the risk to develop alloanti-D (Flegel WA et al. 2007), serologic weak D phenotype is defined as reactivity of RBCs with an anti-D reagent giving no or weak reactivity in initial testing, but agglutinating moderately or strong with antihuman globulin (Fung MK et al. 2014).
It should be realized that at present applied genotyping approach is still not replacing serology, but is only an addition to ABO and Rh serology. Most, if not all blood banks will be reluctant to abandon serology. However, when hundreds of thousands of donors have been genotyped in the near future, it might become clear that serology can be safely omitted. Moreover, the recognition of RHD genes in donors that are falsely typed as D negative by serology already shows that RHD genotyping of donors is superior to RhD serology (Mariza et al., 2009).The aim of this study is to answer an important question how to approach partial and weak D identification in diagnostic use and if it is possible to distinguish between partial and weak D using commercially available anti D reagent for routine use. Approve phenotypes identified by serological test using molecular technique to recognize the common subtype of weak D in our locality.
Our study included a total of 50 samples with discrepant results for Rh D. Thirty nine of them were collected from blood donors and eleven were collected from patients. All of them were recruited from South Egypt Cancer Institute and Assiut University Hospital from October 2016 to May 2018.These samples were tested serologically using ID-Card ˝ID-Partial RhD Typing Set˝ where Serological identification of samples using 6 monoclonal anti D panel, followed by Molecular typing using PCR-SSP kit (for 5 weak D types and the partial D phenotype HMi).
Among the weak D alleles found in our study, type 4 was the most common, with a frequency of 20%, followed by type 3 (14%), type 1 (8%) and type 2 (6%) and Type 5 (3%). And the most common types of partial D were partial D type DV (14%) and type DIII (10%).
In conclusion, our study identified D variants (weak D and partial D categories) of the antigen D and determined the frequency and composition of partial D and weak D alleles in our population. Molecular typing also confirmed most of the results obtained from serological methods.
Weak D variants among Egyptians are significantly different compared with whites, but were found to be similar to those seen in black Africans. Population ethnicity must be taken into consideration when developing transfusion and prenatal strategies related to D variants. It is prudent to systematically implement weak D typing in Egyptian donors.
These data will help us to implement the best alloimmunisation anti-D prevention strategy in our population to improve patient care, especially for those receiving long-term transfusion therapy.