Epitope analysis of weak D type 25 and the transfusion strategy discussion
WANG Zhen;JIA Shuangshuang;CHEN Jingwang;ZHANG Runqing;LUO Guangping;JI Yanli;Institute of Clinical Transfusion,Guangzhou Blood Center;
Objective A case of D variant patient with D positive blood transfusion was identified by serological and molecular tests,and unexpected antibodies monitoring was conducted to investigate the transfusion strategy of this weak D type recipient. Methods Sample was collected,two different kinds of monoclonal anti-D were used to type Rh D antigen serologically. Direct anti-globulin testing( DAT) was conducted in microcolumn gel card. Rh D epitopes were further analyzed by using a commercial epitope detection kit( D-Screen). Unexpected antibodies screening was conducted in microcolumn gel card.Rh Cc Ee antigens were typed by using Rh Blood Grouping Card. The multiplex ligation-dependent probe amplification( MLPA) assay was used to analyze the RHD and RHCE genotypes.When the MLPA was unable to identify a RHD variant,ten exons of the RHD gene were amplified by polymerase chain reaction( PCR) and then analyzed by direct sequencing.Results The results of the preliminary D antigen identification of this patient showed that the D antigen was weakly expressed.DAT was negative. The epitope analysis of Rh D antigen by using the D-screen kit showed the red blood cells of this patient having a weak positive agglutination reaction with three monoclonal anti-D against ep D5. 4,ep D2. 1,and ep D3. 1 epitopes of D antigen,but a negative agglutination reaction with other six monoclonal anti-D. Unexpected antibodies screening results were negative on days 168 and 232 after massive transfusion of D-positive blood. The Rh CE status was cc Ee. The genotyping results of RHCE by MLPA analysis are consistent with the serological typing result.The normal D/d genotype was shown by MLPA analysis and further sequencing of all exons of the RHD gene identified a missense mutation( c. 341 G A,p. Arg114 Gln) in exon3 of the RHD gene.Conclusion This patient was identified as a weak D type 25 blood type. This article for the first time analyzes the D epitopes of weak D type 25,showing some of its epitopes are missing. At the same time,it was the first time to report that a case of weak D type 25 patient did not produce anti-D antibody after a large amount of D positive blood transfusion,providing data for clinical blood transfusion strategy of D variant type.
【Fund】： 广州市医药卫生科技项目(20161A011057);; 广州市医学重点实验室
【CateGory Index】： R457.1
【CateGory Index】： R457.1