Immunohematology and Immunology
Immunohematology is the study of antigens and antibodies associated with blood transfusion and some complications of pregnancy. The application of this knowledge base in CLS is commomly known as Blood Banking or Transfusion Medicine. While safe transfusions of blood and blood products are the main focus of blood banking, larger institutions may be concerned with the immunology of tissue or organ transplantation.
Reactions between RBC antigens and specific (and nonspecific) plasma antibodies result in the coating and destruction of RBCs. A rapid destruction of RBCs releases free hemoglobin into the circulating plasma which may result in renal shutdown, toxemia and death; hence, extreme precautions are taken to ensure safe, compatible transfusions.
A comprehensive understanding of transfusion medicine requires an understanding of immunology, serology and genetics. Recent innovations (<20 years) in enzymatic, recombinant DNA and other biomedical techniques are rapidly expanding the frontiers of knowledge of immunogenetics. Nevertheless, a practical level of knowledge of these subjects is sufficient and satisfactory for the performance of most tasks associated with immunohematology. Crossmatching to confirm transfusion-compatible blood, detection and identification of natural and unexpected antibodies, provisioning and preparation of blood components and their derivatives and detection of hemolytic disease of the newborn (HDN) are among the the most commonly performed immunohematology tasks.
RBC Antigens and Antibodies
An antigen is a substance which elicits the formation of a water soluble, plasma glogular protein known as an antibody. RBC antigens are fixed protein or lipoprotein structures incorporated in the lipid membrane of the RBC. Formation of human RBC antigens are coded by specific nuclear DNA loci and composition known as genes. Since RBC antigens are DNA specific, if one is born with an antigen, he has it for life. Associated inherited variations of alellic genes gives rise to the classifying of antigens into associated groups, i.e., ABO, Rh, Kell, Kidd, Duffy, MNS and others.
An antibody is a globular protein which is manufactured by plasma cells in response to an antigenic stimulus. In normal adults there is about 3 grams of globulin per dL of plasma (3%), most of which is either an immunoglobulin antibody, enzyme or transport protein. The immunoglobulin fraction may be further classified by immunoelectrophoresis into immunoglobulins IgA, IgD, IgE, IgG, and IgM.
(more will follow)
Listed below is the table of contents of the Transfusion Medicine Manual from the UCLA Medical Center. The manual is compact, yet provides much practical information on blood group antigens, antibodies and compatibility testing. Chapter links to their sources are provided.
Transfusion Medicine Manual University of California, Los Angeles, Division of Transfusion Medicine TABLE OF CONTENTS Chapter 1 - Fundamentals of Transfusion Medicine Blood Group Systems The ABO Blood Group System Biochemistry and Inheritance of the ABO Groups The Rh Blood Group System Other Blood Group Systems Consequences of Antibodies to Red Blood Cells Serologic Tests for Red Cell Antibody Detection The HLA System HLA and Transfusion HLA and Transplantation HLA and Parentage Testing HLA and Disease References Chapter 2 - Compatibility Testing What a Physician Needs to Know About Compatibility Testing Blood Sample ABO Typing Rh Typing Antibody Screen Crossmatch Tests Routine Compatibility Testing Policies Surgical Blood Ordering Type and Crossmatch Type and Screen Hold Clot Surgery without a Blood Order Maximum Surgical Blood Order Schedule (MSBOS) Emergency Transfusion Group O, Rh-negative Red Cells, Uncrossmatched Type Specific Blood, Uncrossmatched Circumstances in Which it is Difficult or Impossible to Find Compatible Blood "In Vivo Compatibility Test" Relationship of Compatibility Tests to Fatal Hemolytic Transfusion Reactions References Chapter 3 - Blood Donation General Donor Requirements Donation Process Medical History Review Blood Donation Donor Testing ABO and Rh Antibody Screen Tests Intended to Prevent Disease Transmission Autologous Donor Programs Preoperative Collection Hemodilution Intra/Post Operative Autologous Blood Collection Designated Donor (DD) Programs Apheresis Programs Component Collection Therapeutic Apheresis Procedures References Chapter 4 - Informed Consent, Infectious Complications of Transfusion, and Transfusion Alternatives Informing the Patient and Obtaining Consent for Transfusion Infectious risks of Blood Transfusion Progression of Transfusion Transmitted Infection to Disease Transfusion Alternatives References Chapter 5 - Blood Administration Prior to Transfusion Transfusion Equipment Blood Infusion Sets Needles and Catheters Leukocyte-Removing Filters IV Pumps Pressure Bags Blood Warmers IV Solution and Medications Confirming Patient and Donor Identity Monitoring the Patient During Transfusion Infusion Rates Transfusion Follow-up References Chapter 6 - Transfusion Reactions Signs and Symptoms to Watch for Refer to the Following Pages for Treatment of Life-threatening Reactions Immediate Action to Take for all Suspected Reactions Laboratory Response Reaction Classifications Hemolytic - Immune, Acute (AHTR) Hemolytic - Immune, Delayed (DHTR) Hemolytic - Non-immune Febrile Nonhemolytic Reactions Allergic Reactions Anaphylactic Reactions Transfusion Related Acute Lung Injury (TRALI) Circulatory Overload Bacterial Contamination Metabolic Complications Transfusion-Transmitted Disease References Chapter 7 - Transfusion Practices Transfusion of Red Blood Cells Transfusion of Red Blood Cells for Anemia Transfusion of Red Blood Cells in Surgery Platelet Transfusion Indications for Platelet Transfusion Determining the Appropriate Dose of Platelets Monitoring the Effectiveness of Platelet Transfusions Special Platelet Products for Refractory Patients Fresh Frozen Plasma Cryoprecipitate Granulocyte Transfusion Albumin Special Blood Products Leukocyte-Reduced Blood Components Irradiated Blood Products for Prevention of Transfusion-Associated Graft-versus-Host Disease Blood Products for Prevention of Transfusion-Transmitted Cytomegalivirus (CMV) Infection Intravenous Immunoglobulin (IVIg) Rh Immune Globulin Fibrin Glue Transfusion in Specific Clinical Settings Pediatric and Neonatal Transfusion Practices Hemolytic Disease of the Newborn Neonatal Alloimmune Thrombocytopenia (NAIT) Transfusion of Patient with Sickle Cell Diseaes Transfusing Recipients of ABO-Mismatched Bone Marrow and Solid Organ Transplants Massive Transfusion Transfusion Management of Hemorrhagic Disorders Congenital Deficiencies Acquired and Secondary Disorders of Hemostasis Transfusing Patient with Autoimmune Hemolytic Anemia (AIHA) Therapeutic Apheresis Immune Consequences of Transfusion Indication and Guidelines for the Use of Hematopoietic Growth Factors References Appendix - Quick Reference to Blood Component Therapy Blood Components and Derivatives Preservation and Storage Labeling and General Information Chapter 8 - Transfusion Medicine Education Study Guide Medical Student Objectives References Chapter 9 - UCLA Policies - Quick Reference Guide Essential Phone Numbers Important References Available At Nursing Stations Blood Bank Forms Blood Availability Time Table UCLA Transfusion Audit Criteria Special Blood Products Test Sample Requirements Informed Consent for Transmission Confirming Patient/Donor Identity Before Transfusion Patient Care During Transfusion If Transfusion Reaction Is Suspected Relationship between CCI and PPR
Until I am inspired to compile text which is applicable to immunology as practiced in CLS, the hypertext link below will serve. The reference below is to the online version of Essentials of Immunology by Andy Reese and William Dolen from The Medical College of Georgia. Click here to go to those web pages.
Essentials of Immunology is not intended to be a comprehensive reference for the field of immunology, but is an attempt to provide a comprehensive, manageable update on the general field which is not easily available in other forms.
Chapters
Nonspecific Defense Mechanisms
Complement
Structure, Function, & Genetics of Immunoglobulins
Antigen-Antibody Reactions
Cells & Tissues of the Immune System
Antigen Induced Lymphoproliferation
Control of Immune Responses
Immune Responses to Infections
Atopy (Allergy)
Immunopathology
Tolerance and Autoimmunity
Immunodeficiency Diseases
Immunobiology of Transplantation
Immunobiology of Cancer
Intervention in the Immune Response
Join the conversation