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Abdullah Meshi, BMSc (CLSc), MSc(UK).Head of blood bank

King Fahd central Hospital-Jazan

aalmashi@hotmail.com

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` Blood group systems & Immune response to RBC

antigens.

` Clinical significance of RBC alloantibodies.

` Current and future methods forAbs identification

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`What does immunesystem do??

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` Primary IR Slow (weeks to months

Low level of IgM Needed high dose of

Ag.

` Secondary IR Rapid

Ab titer rising 48 hrs IgG , peaks 6 days

after injection

Need smallerAg dose

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` T-cell-dependent antibody formation

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` Sources of alloimmunisation to RBC antigens:

Blood transfusion

pregnancy

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` Immunogenicity The ability of an antigen to stimulate an immune

response or antibody production.

Most blood group antigens are poor immunogens (

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Antibodies Detected Number of Patients

anti-K

10 (2.8%)anti-E 9 (2.5%)

anti-c 6 (1.6%)

anti-Lea 5(1.4%)

anti-M 4 (1.1%)

anti-E, c 3 (0.8%)

anti-Leb 2 (0.5%)

anti-S 1(0.3%)

anti-D & anti-C 1(0.3%)

anti-c, E & K 1(0.3%)

anti-Lea & Leb 1(0.3%)

anti-Xga 1(0.3%)

others 6 (1.6%)

Total 50 (13.8%)

Blood group antibodies detected in SCD patients at (KFCH), Jazan (n=362) *

*Abdullah S. & Meshi A., 2006 (unpublished data)

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` Acute Haemolytic transfusion reaction (AHTR) Most blood group antibodies can causeAHTR

` Delayed haemolytic transfusion reaction (DHTR) Most blood group antibodies can causeDHTR

` Haemolytic disease of the foetus and newborn

(HDFN) Rh & Kell antibodies.

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` Liquid-phase (tube/plate)

` Column-agglutination (gel cards)

` Solid-phase (microplate coated with RBCs)

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` The genesencoding most of the major blood group

determinants have been cloned & sequenced

` Recombinant DNA technology was applied to

engineer clinically significant blood group antigens

(e.g. Kell, Duffy, Gerbich).

` These recombinant antigens can be used indetecting & identifying Abs in clinical laboratories

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0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

MeanOD(min

us

blank)

sr LAG-K/Kpa/Jsa K300

FLAG-Kell fusion prote in

anti-K

anti-Kpa

anti-k

Antigen capture ELISA*

Meshi A., 2005 (unpublished data)

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Suspension Bridge

Bristol, UK (2005)

THANK YOU