Immunohematology - PDF

IMMUNOHEMATOLOGY Prepared by: Basma Samir (MD) Transfusion medicine What???????????? The branch of medicine that is concerned with the study of blood groups, and the transfusion of blood and blood components. Where???????????? The blood bank is the section of the clinical laboratory...

IMMUNOHEMATOLOGY Prepared by: Basma Samir (MD) Transfusion medicine What???????????? The branch of medicine that is concerned with the study of blood groups, and the transfusion of blood and blood components. Where???????????? The blood bank is the section of the clinical laboratory where medical technologists process and distribute blood products Who?????????????? Under the supervision of a medical director, often certified in Clinical Pathology or Transfusion Medicine. Prepared by: Basma Samir (MD)  Blood transfusion  Across the world, blood products must be prescribed by a medical doctor (licensed physician or surgeon) in a similar way as medicines.  In the USA, blood products are tightly regulated by the U.S. Food and Drug Administration (FDA). Prepared by: Basma Samir (MD) History  In 1901  Karl Landsteiner discovered that when Blood of one human being was transfused with that of another human being, differences in their Blood might be the cause of shock, jaundice, and hemoglobinuria. Prepared by: Basma Samir (MD) Blood Components  Plasma  Packed Red Blood Cells  Leucocytes  Platelets  Others Prepared by: Basma Samir (MD) Blood Type (Blood Group)  A blood type (also called a blood group) is a classification of blood based on: the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). Prepared by: Basma Samir (MD)  Some of these antigens are also present on the surface of other types of cells of various tissues.  Several of these red blood cell surface antigens, that stem from very closely linked genes, collectively form a blood group system. Prepared by: Basma Samir (MD) Blood groups  A complete blood type would describe a full set of substances on the surface of RBCs.  An individual's blood type is one of the many possible combinations of blood-group antigens.  Across the all blood groups, over 600 different blood-group antigens have been found, but many of thesePrepared are very rare. by: Basma Samir (MD)  Prepared by: Basma Samir (MD) BLOOD GROUP ANTIGENS What are the Nature of the different blood groups? The differences in human blood are due to the Presence or Absence of certain protein molecules called antigens and antibodies. The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents. Prepared by: Basma Samir (MD) Blood Group Antigens Proteins These antigens may be proteins, Carbohydrate s carbohydrates, glycoproteins, or Glycoproteins glycolipids, depending on the Glycolipids blood group system. Others Prepared by: Basma Samir (MD) Functions of Blood Group Ags Transporter Adhesion s Molecules Part of RBC Receptors membrane Prepared by: Basma Samir (MD)  Structure Blood group antigens are either sugars or proteins, and they are attached to various components in the red blood cell membrane. Glycosphingolipi ds ABO, P, I Glycoproteins Rh Glycophorins MNS Prepared by: Basma Samir (MD) Glycosphingolipids  CHO  Series of sugars bound to ceramide  Extending from membrane surface  Ceramide: a long base, sphingosine + fatty acid  Sugar chains: 4 at least; may be branched Prepared by: Basma Samir (MD) Glycophorins  Long chain glycosylated amino acids bound by actin to spectrin  Extending through the membrane  Antigens are not integral part of membrane. Prepared by: Basma Samir (MD) Glycoproteins  Embedded in membrane  Do not significantly extend beyond surface  Proteins are DIRECT GENE PRODUCTS. Prepared by: Basma Samir (MD) Inheritance of Blood Group Antigens  Blood types are inherited and represent contributions from both parents.  Many pregnant women carry a fetus with a different blood type from their own, and the mother can form antibodies against fetal RBCs. Prepared by: Basma Samir (MD) Blood Type and Disease Association  Some blood types are associated with inheritance of other diseases; for example, the Kell antigen is sometimes associated with McLeod syndrome. Prepared by: Basma Samir (MD) Blood Type and Disease Association  Certain blood types may affect susceptibility to infections, an example being the resistance to specific malaria species seen in individuals lacking the Duffy antigen. The Duffy antigen, presumably as a result of natural selection, is less common in ethnic groups from areas with a high incidence of malaria. Prepared by: Basma Samir (MD)