- Email: [email protected]
78-P: HLA-A, -B, -DR gene and haplotype frequencies in 27,951 bone marrow donors from Sichuan Province marrow donor registry of China
S46
Abstracts
78-P
HLA-A, -B, -DR GENE AND HAPLOTYPE FREQUENCIES IN 27,951 BONE MARROW DONORS FROM SICHUAN PROVINCE MARROW DONOR REGISTRY OF CHINA. Qiang Chen,1,2 Mei Luo,1 Jue Wang,1 Xueli Chen,1 Shu Huang,1 Jie Zeng,1 Ning Song,1 Zhiqiang Yao,1 Jingxian Chen,1 Tomao Zhao,3 Zhongwei Zheng.1 1HLA Lab, Institute of Blood Transfusion, CAMS, Chendu, Sichuan, China; 2HLA Lab, Sichuan Cord Blood Bank, Chendu, Sichuan, China; 3Molecular and Cellular Immunogenetics Section, National Institutes of Health, Bethesda, MD, USA. Aim: In order to estimate gene and haplotype frequencies of Sichuan Province Red Cross marrow donor registry, part of China Marrow Donor Program. Methods: We analyzed the phenotypes of 27,951 donors, recruited by Sichuan Province Red Cross marrow donor registry, whose phenotypes were determined for HLA-A, -B, and -DRB1 alleles using DNA-based typing methods at low to intermediate resolution. Three-locus haplotype frequency was estimated using the maximum likelihood method. The lowest haplotype frequency that can be reliably estimated at a 95% confidence level was 0.000054. Results: The observed alleles correspond to 20 HLA-A, 47 -B, and 13 -DR antigens. The serologic equivalents of HLA-A36 and DR18 alleles were not observed. A total of 2,180 distinct HLA-A, -B, -DRB1 haplotypes were identified. Using this cut off value, 1,211 haplotypes (56%) were found to be statistically reliable and their cumulative haplotype frequency was 0.9728. The cumulative haplotype frequency of the remainder 969 haplotypes (44%) was 0.0272. The top three of common haplotypes are A2-B46-DR9, A30B13-DR7, and A33-B58-DR17 with frequencies of 0.0574, 0.0213, and 0.0299, respectively. Conclusions: The large sample size and consistent DNA typing methods used in the study allowed the calculation of Chinese HLA haplotype frequencies with increased accuracy. The haplotype frequency data provided are useful for the strategic planning of optimal size of registry.
79-P
THE UCLA INTERNATIONAL MICA EXCHANGE, A NEW COMPONENT OF THE INTERNATIONAL CELL EXCHANGE. M. Lau, A.F. Locke, Q. Zhang, R. Rajalingam, E.F. Reed. UCLA Immunogenetics Center, UCLA, Los Angeles, CA, USA. Aim: In February 2007, a pilot study was initiated within the framework of the International Cell Exchange program to assess MICA genotyping, with the first shipment of 4 DNA samples to 8 reference labs on a blind basis. Methods: 5 labs performed PCR-SSOP, 2 labs used in-house SBT, and one lab used PCR-SSP. The 2 labs that used SBT reported the number of GCT-triplet repeats in exon 5. Results: The results of 16 samples provided a snapshot of the detection of MICA alleles using present typing systems. Samples were specifically chosen to cover as many alleles as possible. MICA*008 (n⫽7) was most frequently detected, followed by MICA*004 (n⫽5), MICA*010 (n⫽5), MICA*027 (n⫽3), MICA*009 (n⫽2) and MICA*011 (n⫽2). Other alleles were MICA*001, *002, *012, *015, *017, and *018, each typed once. Consensus of 80% or greater was attained for many of these alleles. However, several alleles were not decisively resolved, including MICA*002 from MICA*020, MICA*008 from MICA*027, and MICA*009 from MICA*049, due to respective differences in the transmembrane domains. Other typing controversies involved a homozygous MICA*015 sample, with MICA*002/*015/*020 assigned by 4 of 7 labs, MICA*015 by 3 labs, and MICA*002 by 1 lab; and for a MICA*010 sample, MICA*010 was detected by 4 of 6 labs and MICA*016/*019 was misassigned by the other 2 labs. Conclusions: We now offer this program to all interested labs for external quality control and proficiency testing. The exchange of information will help in improvement of typing reliability and resolution. Among our future goals are to achieve standardization in typing of MICA alleles and antibody identification, validate methods and reagents, and identify new alleles. The reports for the pilot studies for MICA genotyping are available on our web site, www.hla.ucla.edu.
Abstracts
78-P
HLA-A, -B, -DR GENE AND HAPLOTYPE FREQUENCIES IN 27,951 BONE MARROW DONORS FROM SICHUAN PROVINCE MARROW DONOR REGISTRY OF CHINA. Qiang Chen,1,2 Mei Luo,1 Jue Wang,1 Xueli Chen,1 Shu Huang,1 Jie Zeng,1 Ning Song,1 Zhiqiang Yao,1 Jingxian Chen,1 Tomao Zhao,3 Zhongwei Zheng.1 1HLA Lab, Institute of Blood Transfusion, CAMS, Chendu, Sichuan, China; 2HLA Lab, Sichuan Cord Blood Bank, Chendu, Sichuan, China; 3Molecular and Cellular Immunogenetics Section, National Institutes of Health, Bethesda, MD, USA. Aim: In order to estimate gene and haplotype frequencies of Sichuan Province Red Cross marrow donor registry, part of China Marrow Donor Program. Methods: We analyzed the phenotypes of 27,951 donors, recruited by Sichuan Province Red Cross marrow donor registry, whose phenotypes were determined for HLA-A, -B, and -DRB1 alleles using DNA-based typing methods at low to intermediate resolution. Three-locus haplotype frequency was estimated using the maximum likelihood method. The lowest haplotype frequency that can be reliably estimated at a 95% confidence level was 0.000054. Results: The observed alleles correspond to 20 HLA-A, 47 -B, and 13 -DR antigens. The serologic equivalents of HLA-A36 and DR18 alleles were not observed. A total of 2,180 distinct HLA-A, -B, -DRB1 haplotypes were identified. Using this cut off value, 1,211 haplotypes (56%) were found to be statistically reliable and their cumulative haplotype frequency was 0.9728. The cumulative haplotype frequency of the remainder 969 haplotypes (44%) was 0.0272. The top three of common haplotypes are A2-B46-DR9, A30B13-DR7, and A33-B58-DR17 with frequencies of 0.0574, 0.0213, and 0.0299, respectively. Conclusions: The large sample size and consistent DNA typing methods used in the study allowed the calculation of Chinese HLA haplotype frequencies with increased accuracy. The haplotype frequency data provided are useful for the strategic planning of optimal size of registry.
79-P
THE UCLA INTERNATIONAL MICA EXCHANGE, A NEW COMPONENT OF THE INTERNATIONAL CELL EXCHANGE. M. Lau, A.F. Locke, Q. Zhang, R. Rajalingam, E.F. Reed. UCLA Immunogenetics Center, UCLA, Los Angeles, CA, USA. Aim: In February 2007, a pilot study was initiated within the framework of the International Cell Exchange program to assess MICA genotyping, with the first shipment of 4 DNA samples to 8 reference labs on a blind basis. Methods: 5 labs performed PCR-SSOP, 2 labs used in-house SBT, and one lab used PCR-SSP. The 2 labs that used SBT reported the number of GCT-triplet repeats in exon 5. Results: The results of 16 samples provided a snapshot of the detection of MICA alleles using present typing systems. Samples were specifically chosen to cover as many alleles as possible. MICA*008 (n⫽7) was most frequently detected, followed by MICA*004 (n⫽5), MICA*010 (n⫽5), MICA*027 (n⫽3), MICA*009 (n⫽2) and MICA*011 (n⫽2). Other alleles were MICA*001, *002, *012, *015, *017, and *018, each typed once. Consensus of 80% or greater was attained for many of these alleles. However, several alleles were not decisively resolved, including MICA*002 from MICA*020, MICA*008 from MICA*027, and MICA*009 from MICA*049, due to respective differences in the transmembrane domains. Other typing controversies involved a homozygous MICA*015 sample, with MICA*002/*015/*020 assigned by 4 of 7 labs, MICA*015 by 3 labs, and MICA*002 by 1 lab; and for a MICA*010 sample, MICA*010 was detected by 4 of 6 labs and MICA*016/*019 was misassigned by the other 2 labs. Conclusions: We now offer this program to all interested labs for external quality control and proficiency testing. The exchange of information will help in improvement of typing reliability and resolution. Among our future goals are to achieve standardization in typing of MICA alleles and antibody identification, validate methods and reagents, and identify new alleles. The reports for the pilot studies for MICA genotyping are available on our web site, www.hla.ucla.edu.