title: Determination of the frequency of the most immunogenic Rhesus antigens among Saudi donors in King Abdulaziz Medical City - Riyadh.
abstract: BACKGROUND
  The Rhesus (Rh) blood group system is one of the most polymorphic and immunogenic systems known in humans, because of its immunogenicity along with ABO grouping, RhD antigen testing was made mandatory before issuing a compatible blood. At present, there are five major antigens, i.e., D, C, E, c, and e in Rh blood group system.
  
  
  OBJECTIVE
  The aim of this study is to provide essential data about the distribution of the major Rh antigens and the most common phenotype among the Saudi population.
  
  
  METHODS
  This is a retrospective study to evaluate the Rh grouping and Rh sub-groups performed among some donors who donated blood or blood products at the department of donation center at King Abdulaziz Medical City Riyadh, Saudi Arabia from January 1, 2014 to December 31, 2014. Sample size included 600 donors. Donors are males and females and their ages are above 18 years.
  
  
  RESULTS
  The incidence of RhD was 84.8% and only 15.2% of samples were negative for D antigen. The Incidence of other Rh antigens C, E, c, and e were 62.3%, 23.5%, 74.3%, and 95.0%, respectively. The most common phenotype among RhD positive donors was DCcee (28.7%) and among RhD negative donors was dccee (13.7%). However, three donors (0.5%) were negative for antithetical antigens C and c.
  
  
  CONCLUSIONS
  This study shows that there is a wide racial and geographical variation in the distribution of Rh antigens and phenotypes among study participants. The Rh blood group system has a vital role in population genetic study and in resolving medical legal issues and more importantly in transfusion medicine practice.
authors.affiliation: Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
authors.forename: Mohieldin
authors.initials: M
authors.lastname: Elsayid
authors.affiliation: Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
authors.forename: Faris Saeed
authors.initials: FS
authors.lastname: Al Qahtani
authors.affiliation: Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
authors.forename: Abdulaziz Mohammed
authors.initials: AM
authors.lastname: Al Qarni
authors.affiliation: Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
authors.forename: Faisal
authors.initials: F
authors.lastname: Almajed
authors.affiliation: Department of Transfusion Medicine Services, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Saudi Arabia.
authors.forename: Faisal
authors.initials: F
authors.lastname: Al Saqri
authors.affiliation: Department of Research, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
authors.forename: Shoeb
authors.initials: S
authors.lastname: Qureshi
keywords: Antigens; Rhesus; blood group; phenotypes