title: Analysis of density and epitopes of D antigen on the surface of erythrocytes from DEL phenotypic individuals carrying the RHD1227A allele.
abstract: BACKGROUND
  The characteristics of the D antigen are important as they influence the immunogenicity of D variant cells. Several studies on antigenic sites have been reported in normal D positive, weak D and partial D cases, including a comprehensive analysis of DEL types in Caucasians. The aim of this study was to assess D antigen density and epitopes on the erythrocyte surface of Asian type DEL phenotypic individuals carrying the RHD1227A allele in the Chinese population.
  
  
  METHODS
  A total of 154 DEL phenotypic individuals carrying the RHD1227A allele were identified through adsorption and elution tests and polymerase chain reaction analysis with sequence-specific primers in the Chinese population. D antigen density on the erythrocyte surface of these individuals was detected using a flow cytometric method. An erythrocyte sample with known D antigen density was used as a standard. Blood samples from D-negative and D-positive individuals were used as controls. In addition, D antigen epitopes on the erythrocyte surface of DEL individuals carrying the RHD1227A allele were investigated with 18 monoclonal anti-D antibodies specific for different D antigen epitopes.
  
  
  RESULTS
  The means of the median fluorescence intensity of D antigen on the erythrocyte membrane surface of D-negative, D-positive and DEL individuals were 2.14±0.25, 193.61±11.43 and 2.45±0.82, respectively. The DEL samples were estimated to have approximately 22 D antigens per cell. The samples from all 154 DEL individuals reacted positively with 18 monoclonal anti-D antibodies specific for different D antigen epitopes.
  
  
  CONCLUSIONS
  In this study, D antigen density on the erythrocyte surface of DEL individuals carrying the RHD1227A allele was extremely low, there being only very few antigenic molecules per cell, but the D antigen epitopes were grossly complete.
authors: Department of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China.
authors: Juan
authors: J
authors: Gu
authors: Department of Clinical Laboratory, The Affiliated Provincial Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.
authors: An-Yuan
authors: AY
authors: Sun
authors: Department of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China.
authors: Xue-Dong
authors: XD
authors: Wang
authors: Shenzhen Blood Center and Institute of Blood Transfusion Medicine, Shenzhen, Guangdong, People's Republic of China.
authors: Chao-Peng
authors: CP
authors: Shao
authors: Department of Clinical Laboratory, The Affiliated Hospital of Guilin Medical College, Guilin, Guangxi, People's Republic of China.
authors: Zheng
authors: Z
authors: Li
authors: Department of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China.
authors: Li-Hua
authors: LH
authors: Huang
authors: Department of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China.
authors: Zhao-Lin
authors: ZL
authors: Pan
authors: Department of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China Department of Clinical Laboratory, the Shaoxing Hospital of China Medical University and Central Hospital of Shaoxing County, Shaoxing, Zhejiang, People's Republic of China.
authors: Qing-Ping
authors: QP
authors: Wang
authors: Zhenjiang Maternal & Children Health Care Hospital, The Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China.
authors: Guang-Ming
authors: GM
authors: Sun
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D000939:Epitopes / Q000235:genetics / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D012204:Rh-Hr Blood-Group System / Q000235:genetics / Q000378:metabolism*
chemical_list: D000939:Epitopes; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen