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Flashcards in Principles of Transfusion Deck (19):
1

What were the common complications of early blood transfusion?

-shock
-diffuse bleeding
-kidney failure
-death

2

Which blood group is the universal recipient? Universal donor?

-Type AB
-Type O

3

Who is the universal PLASMA donor?

AB (no antigens in plasma)

4

What enzymes determine the erythrocyte surface peptidoglycans that define blood group?

glycosyltransferase enzymes

5

Severity of transfusion reactions correlates with activation of what?

-Complement --> causes lysis of RBCs

if severe enough, inflammation results as well

6

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

7

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,

8

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

9

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

10

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

11

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

12

What is the most important minor blood group antigen?

RhD

-very immunogenic, 15% Caucasians are RhD (-)

13

What is the most common cause of HDFN (hemolytic disease of the fetus/newborn)?

RhD non-concordance

14

How are RhD negative women with RhD positive fetuses treated?

immunized with anti-RhD immune globulin

15

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

16

If there is no time to do compatibility testing/crossmatch tesing, what is the safest blood type to give someone?

O-neg (O-RhD neg)...short supply (7% pop)

17

How was clotting during transfusion prevented in the past? Now (in blood banks)?

-past: artificial anastamosis
-today: citrate (bind Ca++ in blood, prevents coagulation cascade activation)

18

What are concerns and solutions for storing blood?

-clotting: citrate additive
-spoilage: glucose, adenine, phosphate
-contamination: aseptic collection/storage, refrigeration (4 deg celcius)

19

What is apheresis?

collection of a single blood component directly from donor