IMPROVING RESULTS IN SSP LOW RESOLUTION TYPING

Olerup SSP

Olerup SSP® Low resolution Kits –Flexibility and Convenience

• A comparative study of different kit formats for:– HLA-A – HLA-B– HLA–DRB

• Objective:– To investigate the frequencies of typing ambiguities for low resolution SSP typings in two sets of

samples – To compare the performance of the ”classic” formats to the new formats.

• Material and Methods

– 102 randomly selected Swedish blood donors

– 102 consecutive UCLA Exchange DNAs

– The most current lots of the Olerup SSP® kits for HLA-A, -B and -DRB low resolution typing• ”classic” format vs new, extended formats

– Analyzed using Olerup SSP ® version of Helmberg-SCORE™ , allele database 3.5.0

HLA-A HLA-B HLA-DRBAll samples, "classic

format" 14% 16% 3,4%

All samples, new format 0,5% 1,5% 0,0%

0%

5%

10%

15%

20%

25%

30%

35%

40%

Low

reso

lutio

n am

bigu

ities

(%

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Product formats vs Low Resolution Ambiguities,All samples

Product formats vs Low Resolution Ambiguities,Sample Breakdown

HLA-A HLA-B HLA-DRB

”Classic” format

New format

”Classic” format

New format

”Classic” format

New format

All samples(n=204)

14% 0,5% 16% 1,5% 3,4% 0,0%

Random samples(n=102)

16% 1,0% 17% 1,0% 0,5% 0,0%

UCLA samples(n=102)

12% 0,0% 16% 2,0% 5,9% 0,0%

Olerup SSP® Low resolution Kits –Examples of improved low resolution

HLA-A

–Improved resolution for A*01,03; A*01,11 and A*03,11 samples

• Resolves for example: – 01:01,03:01=03:01,03:18 and

1:01,11:01=11:01,11:94

–Improved resolution for samples containing A*26, A*66 or A*34 alleles

• Resolves for example:– 01:01,26:01=03:18,26:01– 11:01,26:03=03:75,11:10– 26:01,66:02=26:09,26:65=26:65,43:01– 66:01,66:02=34:01,66:12

–Improved reactivity pattern for A19-samples• A19-specific vial included

– Will decrease risks of new alleles with blank reactivity patterns. Thereby sustaining resolution for homozygous samples

HLA-DR

• Improved resolution for DRB1*13,13; DRB1*13,14 and DRB1*14,14 samples

• Resolves for example:– 13:01,14:02= 14:21,14:24– 14:01,14:02=13:44/86,14:01 – 13:03,14:01=03:76,14:01=14xx,14xx– Improved resolution for samples

containing DRB1*03, DRB1*08, DRB1*07, DRB1*09 or DRB1*12

Olerup SSP® Low resolution Kits –Examples of improved low resolution

HLA-B

–Improved resolution for B*07,39 and B*07,40 samples

• Resolves for example:– 07:02,39:01=07:69,67:01– 07:02,39:02=48:05,67:01– 07:02,40:01=40:xx, 40:166

–Improved resolution for B*35 samples• With respect to B*18-alleles

–Improved resolution for B*08:01 homozygous samples

–Improved resolution through B*42 specific primer mix

• Resolving various ambiguities for samples containing for example B*07, B*08, B*27 or B*39 alleles

–Improved resolution for B62,B63 samples. Separated from B15- and B62 serological equivalents

–Exon 2-3 (Intron 2 spanning) primer pairs included

• Resolves for example:– B*35:01:01:01,51:01:02=B*53:01:01,78:

02:01

Confidential - for internal use only

Olerup SSP® Low resolution Kits –Flexibility and Convenience

• Conclusions– Low resolution kit format expansion result in a significant decrease

of ambiguities for both sample populations

– Possible in new format to include primer pairs spanning Class I intron 2• resolves for example B*35:01:01:01,51:01:02 = B*53:01:01,78:02:01

• Benefits of the format change – will enable us to continue to:

• cover all alleles as databases are released• Sustain high quality low resolution• Increase genotype resolution