Post on 13-May-2015
description
Deepa Babin @TMC Kollam 1
The study of immunologic reactions involving all components of
blood
Deals with antigens, antibodies and antigen-antibody reactions
IMMUNOHEMATOLOGY
Deepa Babin @TMC Kollam 2
Application in ....
transfusion of blood & its components diagnosis, prevention & management of
immunization asso with pregnancy
leukocyte testing for organ
transplantation laboratory resolution of parentage
problemsDeepa Babin @TMC Kollam 3
Agglutination / Hemolysis
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Complete Antibodies
antibody
+
RBC w/ antigen
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Incomplete Antibodies
+
RBC w/ antigenantibodies
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1. ABO BLOOD GROUP2. Rh BLOOD GROUP SYSTEM3. OTHERS
A. MNSB. I/i C. DUFFYD. KELLE. KIDDF. PG. LUTHERANH. LEWIS
BLOOD GROUP SYSTEMS
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ABO BLOOD GROUP
First blood groups discovered-Landsteiner(1900)
Most significant for transfusion practice
ABO compatibility is essential before other pretransfusion test is performed
ABO antigens are the only Ags for which reciprocal antibodies consistently and predictably exist in serum of normal individuals
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ABO BLOOD GROUP
Anti-AAnti-BAnti-A,B
noneO
Blood Group RBC AgA AB B
AB A & BO none
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GROUP A Express A antigen on RBC surface Genotypes AA or AO Have naturally occurring, clinically
significant, predominantly IgM (with a small amount of IgG) antibodies against type B (anti-B)
Subgroups A1 (80%) A2 (20%) Significance: some with A2 have antibodies
against the A1 subgroup (anti-A1)
ABO BLOOD GROUP…
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ABO BLOOD GROUP…
GROUP B Express B Ag on RBC
surface Genotypes BB or BO Have naturally
occurring clinically significant, predominantly IgM (with a small amount of IgG) antibodies against type A cells
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ABO BLOOD GROUP…
GROUP O Have neither A nor B antigens on their RBC Genotype OO (“universal donors”) Have naturally occurring, clinically
significant, very high titer, anti-A, anti-B and anti-A,B antibodies
Maternal anti-A,B can cross the placenta to cause hemolytic disease of the newborn
Group O cells have the most H antigen
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ABO BLOOD GROUP…
GROUP AB Express A and B
Ag on RBC surface
Genotypes A1B or A2B
have no ABO antibodies (“universal recipients”)
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H Antigen Seen on RBC of ABO-Universal
distributed
BOMBAY (Oh)PHENOTYPE Patients lack the H gene and
therefore cannot make H antigen, A or B antigen on their red cells
Have very strong anti-A, anti-B, and anti-H and can only receive cells from a Bombay donor
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ABO BLOOD GROUPS
Serum AbSerum AbRBC AgRBC AgBlood Blood GroupGroup
Anti-BAA
Anti-ABBB
noneA & BAB
Anti-AAnti-BAnti-A,B
noneO
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Blood being testedTyping Serum
Type AB (contains agglutinogenA and B )
Type B (contains agglutinogen B)
Type A (contains agglutinogen A)
Type O (contains no agglutinogen)
Anti – A Anti – B
red cells
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ABO BLOOD GROUP… Testing
REVERSE GROUPING /TYPING Also called “serum” or “back” typing
Uses patient’s serum versus commercial A1 and B cells
Analyzes patient’s serum for the presence of anti-A and anti-B antibodies
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ABO BLOOD GROUP… Testing
Testing for antibodies is not reliable until 6 months of age Newborn serum
may contain maternal IgG anti-a or anti-B
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Rh BLOOD GROUP …
Complex blood group with >50 described antigens
Rhesus monkey D Ag is more potent No natural AB against Rh Nomenclature systems
Fisher-Race (English) Wiener (American)
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Rh Groups: Fisher-Race
Anti-eAnti-e
Anti-CAnti-C
Anti-DAnti-D
genesgenes
linkedlinked
closely-closely-
ee
CC
DD
AbAbAgAgChromosomeChromosome
ee
CC
DD
5 major antigens: D, C, E, c and e Deepa Babin @TMC Kollam 22
Rh Groups: Weiner
RhRh11
hr”hr”
Anti- hr’Anti- hr’hr’hr’
Anti-rh”Anti-rh”rh”rh”
Anti-rh’Anti-rh’rh’rh’
Anti-RhoAnti-RhoRhoRho
AbAbAgAgCHROMOSOMECHROMOSOME
RR11 singlesingle genegene
Anti- hr”Anti- hr”
5 major antigens: Rho, rh’, rh”, hr’, hr”
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Rh BLOOD GROUP… Testing
Testing for D(Rho) is the most common Rh test performed
D antigens are potent immunogens. Of D-negative patients, 80% will develop
an anti-D when transfused with a single unit of D-positive blood.
* Rh-positive simply means “D positive”
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Other blood group systems:
Kell (K,k,Kx)
Duffy (Fy)
Kidd (Jka, Jkb)
MNSs
P
Lewis (Le)
Lutheran (Lu)
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Importance of other blood groups:
May cause transfusion reactions or
HDN
May interfere with crosshatching
For medico legal parenthood problems
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COMMON TESTS USED IN IMMUNOHEMATOLOGY
Coombs Test (Antiglobulin Test) RBC typing Crossmatching Antibody Screening Compatibility Testing
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I. ANTIGLOBULIN (COOMB’S) TEST
Remains the most important single test in Ab detection
Principle: Red blood cells sensitized by IgG or
complement can be made to agglutinate by adding antihuman globulin
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I. ANTIGLOBULIN (COOMB’S) TEST
DIRECT COOMB’S TEST (DAT)
Detects RBCs that have already been sensitized with IgG
Demonstrates that in vivo coating of RBC by Ab has occurred but does NOT identify the antibody
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INDIRECT COOMB’S TEST (IAT) Detects antibodies to RBC antigens present in
the patient’s serum
Detects in vitro red cell sensitization if red cells contain antigen corresponding to serum antibody
Procedure: STEP 1: patient’s serum (with unknown Ab) + RBC (with known Ag)
STEP 2: product of step 1 + Coomb’s reagent
I. ANTIGLOBULIN (COOMB’S) TEST
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ANTIGLOBULIN TESTINGDIRECT ANTIGLOBULIN TEST (DAT)Patient’s red cells
INDIRECT ANTIGLOBULIN TEST (IAT)Patient’s serum
Detects in vivo antibody coating (sensitization) of red cells
Detects in vitro red cell sensitization if red cells contain antigen corresponding to serum antibody
Useful in:1.Detection of hemolytic disease of the newborn (employing infant’s red cells)2.Investigation of transfusion reactions3.Detection of autoimmune hemolytic anemia (AIHA)4.Detection of red cell sensitization by drugs (penicillin, cephalothin, alpha-methyldopa)
Useful in:1.Detection and identification of unexpected antibodies2.Compatibility testing (cross-matching)3.Red cell antigen phenotyping4.Investigation of transfusion reactions5.Detecting Du antigen (weak D)
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II.RBC typing
Forward typing
Reverse typing
D antigenDeepa Babin @TMC Kollam 35
III.CROSSMATCHING
Absence of agglutination or hemolysis is essential to the safety of blood transfusions
Agglutination or hemolysis in any phase of the transfusion (ie incompatibility) = presence of Ab and its corresponding Ag
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III.CROSSMATCHING
Uses
1.To detect antibodies in the donor or recipient
2.To detect ABO typing discrepancies
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IV. ANTIBODY SCREEN
Use: to demonstrate unexpected antibodies in the serum of the recipient that may destroy donor RBCs that were thought to be compatible on the basis of the Rh and ABO typing
Has replaced minor cross matching
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V. PRE-TRANSFUSION / COMPATIBILITY TESTING
1. Review of recipient’s blood bank history
2. ABO and Rh typing of recipient & donor
3. Antibody screening of recipient &
donor serum
4. Major crossmatching
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HEMOLYTIC DISEASE OF THE NEWBORN (HDN)
Also referred to as erythroblastosis fetalis
Occurs when the mother is alloimmunized to antigen(s) found on the RBC of the fetus
Destruction of fetal RBCs by mother’s IgG antibodies
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HEMOLYTIC DISEASE OF THE NEWBORN(HDN) Rh Incompatibility
Rh (-) mother & Rh (+) baby
ABO Incompatibility
“O” mother & “A” or “B” baby
Rh Incompatibility
Rh (-) mother & Rh (+) baby
ABO Incompatibility
“O” mother & “A” or “B” baby
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HDN DUE TO RH INCOMPATIBILITY Set-up: Rh(-) mother + Rh(+) baby
Rh (-) person exposed to Rh(+) blood will develop reaction after 2 – 4 weeks
Mother develops antibody against the Rh(+) blood coming from the baby
First baby is not affected; HDN occurs during subsequent pregnancies
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Rh(-) RBC
Rh(+) RBC
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Antibody
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anemia hemoglobindegradation
extramedullaryhematopoiesis
hydrops
hypoxic injury toliver & heart
bilirubin
jaundice kernicterus
hepato-splenomegaly
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Kernicterus
Hydrops
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HDN DUE TO RH INCOMPATIBILITY
May be prevented by giving anti-Rh
to Rh(-) mother in the ante-natal (28
weeks) & immediate postnatal period
(within 72 hours after delivery)
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ABO Hemolytic disease
Maternofetal ABO incompatibility
A &B got IgM in blood which cannot cross placenta
O gp IgG-CROSS PLACENTA-HEMOLYTIC DISEASE
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COMPLICATIONS OF BLOOD TRANSFUSION
Immunological/Non immunological
Infectious parameters(HIV,HBV,HCV,VDRL)
CMV,LEPTO ,MALARIA,TOXO,LEISH)
AUTOLOGUS BLOOD TRANSFUSION
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Programme created for Basic Vision on
Immunohematology Deepa Babin *
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