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Case # 2
• Clinical progress: 2009
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HLA typing: no sibling match
Hb S: 27-40%
anti-S, anti-Jk(b)
TCD velocities conditional range: < 200 cm/s
Liver iron content (MRI):
6.7 mg Fe/g
RBC transfusion # 16
Commenced Deferasirox (oral Fe chelator)
• 2010
• Hb S: 16-28%
• Brain MRI/MRA: moderate narrowing of A1 segment of ACA
• Blood bank: DAT weakly POS anti-IgG (probable autoAb)
Transfusion in Patients with Haemoglobinopathies
(Sick Kids approach)
• Thalassemia (including congenital anemia like Diamond
Blackfan Syndrome) and sickle cell disease
• Extended red cell phenotyping before first transfusion:
– Rh (C, E, c, e), K1(Kell), Fya, Jka, (Jkb, S in SCD patients)
• Patient already transfused
– Hypotonic saline (0.3% NaCl will lyse normal cells but not
sickle cells)
AABB Technical Manual 15th edition Method 2.16
– Molecular genotyping
– Family studies
• Prophylactic antigen matching:
• Thalassemia: K negative
• SCD: Rh and K matched, Fya, Jk, (S) if alloimmunized (No
need for prophylactic Fyb matching
• Why not Fyb?
Fy(a-b-) Phenotype
• Frequency
– Very rare (0%) in Caucasians and Asians
– 68% in Africans
• Mutation in the promoter region of FYB (–33 T>C), which
disrupts a binding site for the erythroid transcription factor
GATA-1 and results in the loss of Fy expression on RBCs.
• Because the erythroid promoter controls expression only in
erythroid cells, expression of Fy proteins on endothelium is
normal in people with Fy(a–b–) RBCs.
• To date, all blacks with a mutated GATA box have been
shown to carry FYB, therefore Fyb is expressed on their
nonerythroid tissues.
• This explains why Fy(a–b–) individuals make anti-Fya but not
anti-Fyb.
Immunohematology 2004;20:37-49
The Duffy Antigen/Receptor Chemokine locus
• Comprised of 2 exons, spanning ~2 kbp in the region of
chromosome 1q22-23
• The single gene is responsible for the expression of Duffy
antigens on RBCs and other non-erythroid tissue
• Promoter GATA-1 box mutation is responsible for the
Fy(a-b-) RBC phenotype (pseudo-null)
• The gene product has no obvious function on the surface
of RBCs; null RBCs appear to function normally
• FY affords protection from malarial invasion
• It has been proposed that the gpFy modulates chemokine
levels in the blood; regulation of inflammation by
scavenging chemokines
Allelic variants of DARC
GATA-1
(wt) FYB
^
-33T
FYA
^
-33T
(amorph) FY
^
-33C
FYX
^
-33T
(null) FY0
^
-33T
FY*A/FY*BFY*X
^
125A
^
125G
^
^
265C
^
265C
^
125A
265C
^
125A
265T
^
125A
^
^
265C
Transfusion in Patients with Haemoglobinopathies
(Sick Kids approach)
• Start with SAGM units (prestorage leukoreduced)
• 15 to 20 ml/kg, SAGM red cells have hct approx 0.6
• SCD: Units tested by sickle test (sickle negative for
exchange transfusions)
• Repeated allergic reactions: pre-med
• Recurrent allergic reactions: plasma-reduce
• Frequent allergic reactions: Washed red cells from
CBS: 24 hours shelf-life
• Currently, no Sick Kids patients on washed cells
Case #3
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Female, born in 1980, sickle cell disease
B pos, C-E-c+e+, K-, Fy(a-b-), Jka(a+b+)
1998: no antibody, transfused 3 units
1999: anti-K, anti-C, anti-E, autoantibody
Sept 1, 2004, transfused 2 units, O neg, C- EK- S- Fya-, crossmatch compatible
• Sept 14, 2004, 3 units B pos, C- E- K- S- Fya-,
crossmatch incompatible
Case #3 (2004)
• Anti-IH
– 4+ with group O cells by Sal I.S., 370C and IAT
– 1-2+with group B cells
– Negative to weak with Oh (Bombay) cells
• Testing with Oh cells
Cell
IS
370C
IAT
H-, M-
0
w
1
H-, M+N+
w
2
3
H-, M+N -
2
4
3
Anti-IH
• I antigen: subterminal portion of the oligosaccarides that are
eventually converted to H, A, and B antigens
• Most normal adult RBCs are I-positive
• H antigen is the substrate for A and B antigens
• H antigen expression: O > A2 > B > A1B > A1 > A1B
• The most common cold autoagglutinins are directed against the Ii
blood group
• The most commonly encountered cold autoagglutinin recognizing
complex ABH-Ii antigens is anti-IH
• Anti-IH does not generally interfere in pretransfusion testing done at
370C, but may be picked up in MTS-gel
• Anti-IH is usually not clinically significant, anti-IH causing hemolytic
transfusion reaction is very rare but has been reported.
Transfusion 2000:40;828
Case #3 (2005-2006)
• Anti-IH not detectable
• Autoantibody
• Recommended for transfusion: group B, C- E- KM- Fya• May 5, 2006, transfused 2 units O pos, C- E- KFy(a-b-) S-, MTS compatible, Hb  70 to 99 g/L
• May 15, 2006, Hb  to 50g/L
• Strongly reactive with all cells tested, except for 2
Group B Rhnull cells
• Episode of hyperhemolysis, eventually recovered
Case #3 (2008)
Antibodies to high prevalence antibodies
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Red cell alloantibodies
– k, Kpb, Lub, Jsb
– Jk3, U
– African ethnicity: SsU, Jsb, Ata (Augustine), Hy (Holley),
Joa (Joseph)
1. Phenotype patient’s RBCs (Rh and others)
2. Antigen negative cells
3. Enzymes and chemicals
Antibodies to reagent/preservative
ABH antibodies
– Group O patient, think Bombay or para Bombay
– Non group O patient, think IH (more common in A1, A1B,
less common A2, B, A2B)
Case #3 (2008)
Case #3 (2008)
Summary
• Phenotype patient before 1st transfusion
• If transfused, hypotonic saline for SCD, molecular
genotyping and family studies
• Autoantibodies are common
• SCD patients can make unusual alloantibodies
• When investigating for high incidence antibodies,
do not forget ABO and reagents
• Clinical information including patient’s ethnic
background
References
• Guidelines for Antibody Investigation.
AABB 2010
• Judd’s Methods in Immunohematology, 3rd
edition, AABB Press 2008.
• The Blood Group Antigen Facts Book, 2nd
edition, 2004, Reid & Lomas-Francis,
NYBC
• Applied Blood Group Serology 4th edition.
Issitt 1998.