Principles of Transfusion Flashcards
What were the common complications of early blood transfusion?
- shock
- diffuse bleeding
- kidney failure
- death
Which blood group is the universal recipient? Universal donor?
- Type AB
- Type O
Who is the universal PLASMA donor?
AB (no antigens in plasma)
What enzymes determine the erythrocyte surface peptidoglycans that define blood group?
glycosyltransferase enzymes
Severity of transfusion reactions correlates with activation of what?
-Complement –> causes lysis of RBCs
if severe enough, inflammation results as well
What do C3a and C5A complement fragments do to cause inflammation?
- release of histamine, bradykinin and other anaphylotoxins
- stimulate neutrophils to degranulate + undergo respiratory burst
- stimulate macrophages to release proinflammatory cytokines (TNF-alpha, IL-8, MCP-1)
- TNF-alpha causes fever, leukocyte activation, procoagulant activity
Minor blood groups that are discordant cause what, less severe, transfusion reaction?
- delayed hemolytic transfusion reaction
- anamnestic response (response to previously encountered Ag)
- RBC’s hemolyzes 4-11 days post-transfusion
- symptoms: fever, falling Hgb, rising bilirubin, rising LDH, falling haptoglobin,
What fatal outcome can occur when minor blood groups in fetus don’t match with mother?
‘hemolytic disease of the fetus/newborn’
sx: fetal anemia, hydrops (heart failure, anasarca-edema), acute bilirubin encephalopathy, kernicterus
What Ig type commonly bind ABO antigens?
Abs to minor blood groups?
- IgM pentamers (can bind multiple erythrocytes at once–> agglutination)
- IgG monomers (bind one erythrocyte at a time)= partial/incomplete agglutinins
What test allows us to detect antibodies to minor blood group antigens? What is it composed of?
Antiglobulin Test (Coombs’ Test)
-antibody to an antibody ie. anti-IgG causes RBCs coated in antibodies to agglutinate
What two types of antiglobulin tests are there?
- DAT: direct antiglobulin test i.e. antiglobulin mixed with erythrocytes –> DAT-positive hemolysis
- IAT: indirect antiglobulin test ie. antiglobulin mixed with plasma and erythrocytes
What is the most important minor blood group antigen?
RhD
-very immunogenic, 15% Caucasians are RhD (-)
What is the most common cause of HDFN (hemolytic disease of the fetus/newborn)?
RhD non-concordance
How are RhD negative women with RhD positive fetuses treated?
immunized with anti-RhD immune globulin
What are examples of antibodies to blood groups that are not significant clinically? Why are they not a problem?
- Lewis, P, M antigens: only bound withen cold temperatures
- HLA antigens: weakly expressed by RBC
