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HLA Matching for Platelet Trasnfusions

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Dr Andrea Harmer
National Head of NHSBT H&I Services
Refractory patients
Patients with platelet disorders e.g. Glanzmann s /
Bernard Soulier s
HLA-selected platelets are directed donations
for a named patient
Definition
Increase in patient s platelet count of <10 x 109/l at
between 1 and 24 hours after the transfusion of an
adult dose of ABO compatible platelets on two
separate occasions
Immune
Platelet alloantibodies
anti HLA (>95%)
anti HPA (<5% HPA + HLA,
HPA only <1%)
Other antibodies
Autoantibodies
Drug-dependent antibodies
ABO antibodies
Immune complexes
Non Immune (80%)
Splenomegaly
DIC
Bleeding
Consumption (eg ECMO)
Infection and its treatment
e.g. amphotericin B
20000
18000
16000
14000
12000
10000
8000
6000
4000
2000
0
2008
2009
2010
2011
2012
2013
2014
Strategies for treating refractoriness due to HLA antibody
fully HLA match patient and platelet donor
select platelets lacking any antigens to which patient has antibody
Patient s HLA type & antibody data
Search platelets in stock for best available match
HLA match grades
A - full match at HLA-A,B
B1 - single antigen mismatch
B2 - 2 antigen mismatches
B3 - 3 antigen mismatches
B4 - 4 antigen mismatch
Matching
Patient - HLA A2,24 B44,62
antibody specificity A1,3,11 B7,27,60,61
Donor 1 HLA A2 B44,62 (A match)
Donor 2 HLA A2,68 B44,62 (B1 match)
Donor 3 HLA A1,2 B44,62 (B1 match)
Donor 4 HLA A2,31 B8,44 (B2 match)
Donor 5 HLA A2,25 B7,45 (B3 match)
Better responses to A and B1 mm vs B2-B4
Match Grade
90
80
70
60
%
50
40
30
20
10
0
Apr-13 May-13 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr-14 May-14 Jun-14 Jul-14 Aug-14 Sep-14
A
B1
A and B1
Wherever possible 24 hrs notice required this is so that the best
possible match for the patient can be obtained
If only CMV- platelets are requested for patients, then
this reduces the donor pool for matching and in some
cases will result in a less well matched component being supplied
than would be the case if CMV unselected was accepted
HLA platelets must be subject to ongoing increment
measurement
To inform future provision and fine-tuning of matching
selected platelets for best outcome in patients
HLA type A1,32 B7
HLA Antibodies A11, A2, A23, A24, A25, A26, A29, A3, A30, A31, A33, A34, A43, A66, A68, A69, A74,
A80, B13, B18, B35, B37, B38, B39, B41, B42, B44, B45, B46, B47, B48, B49, B50, B51, B52, B53, B55, B56, B57,
B58, B59, B60, B61, B62, B63, B64, B65, B67, B71, B72, B75, B76, B77, B78, B8, B82
Date
Order type
Match Grade
DSA
11/9
Routine
A
N
19/9
On-call
B2
Y
20/9
On-call
B3
Y
20/9
On-call
B2
Y
25/9
Routine
B1
Y
27/9
Routine
B1
N
28/9
Routine
B1
N
30/9
Routine
B1
N
Required to aid in platelet selection
Identify unacceptable antigens
Identify acceptable antigen
National average return rate 2013 only
33.57%
Range 57.68
3.43%
Platelet increments
Patient WS A2 B7 antibodies 96% A3++
Date
Donor type
04/5/05
09/5/05
11/5/05
17/5/05
18/5/05
23/5/05
27/5/05
A2,30B7,40
A2 B7,27
A2 B40
A2,24 B7,39
A2 B7,27
A2 B7
A2 B40
Pre
count
5
7
9
6
3
15
6
Post
count
6
33
30
3
45
53
34
To aid in platelet selection
Identify unacceptable antigens
Identify acceptable antigen
To achieve better clinical response
To identify if HPA testing is required
To identify if further samples are required for HLA
antibody testing
To not waste a precious resource
Not an off the shelf product
Can be time consuming
Full matches not possible for majority of patients
For best patient response
Good planning needed to get best product
Increment data to inform selection
Patients with rare HLA types and/or multiple
antibodies, especially those with HLA + HPA,
may be difficult to support
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