15.1.1 Blood Groups.

Blood groups are characterized by erythrocyte (red blood cell) antigens with common immunologic properties (eg, group A). Blood group systems are series of such antigens encoded by a single gene or by a cluster of 2 or 3 closely linked homologous genes (eg, ABO system).There are about 600 recognized erythrocyte antigens. The International Society of Blood Transfusion (ISBT) designates around 270 blood group antigens. Of these, around 250 belong to 1 of 29 systems., (Other antigens remain in officially designated series or collections.) Some antigens are erythrocyte-specific; others appear widely, but specifically, on cells of other organs and tissues.The discovery ...Less