- Email: [email protected]
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Abstracts / Human Immunology 73 (2012) 49–167
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A ‘‘NEW’’ APPROACH TO RELATED BONE MARROW DONORS. Lynda Thompson, Linda McEneny. Histocompatibility Lab, McMaster University Medical Centre, Hamilton, ON, Canada. Aim: To investigate changing protocol for HLA typings on related Bone Marrow (BM) Donors. Current protocol: Recipient typed at low res with ABDRDQ kit. Siblings typed at low res with ABDR kit. Matched Donor at low prompts BM program to select donor for further testing which initially includes high res DR for Recipient & Donor. If matched, low res C & high res A, B & C performed for matching pair. Methods: DNA extraction using manual salting-out extraction kit by Qiagen. PCR-SSP using low & high resolution primer kits by One Lambda & Olerup. Results: Typing performed on Recip: A⁄01,29,B⁄57,56,DRB1⁄07,01,B4⁄,DQB1⁄02,05. Typings on 3 sibs all resulted in matches at low res ABDR. Donor selection made by BM program, we proceeded with high DR typing to confirm match. Confirmed DRB1⁄07:01, 01:02, followed by low C typing: results C⁄06,16. Performed high res A, B & C for Recipient & Donor. Questioned likelihood of 4 sibs matching at all loci. Unlikely frequency, prompted (outside protocol) high DR on other 2 siblings. Two sibs matched at high DRB1. For education, we confirmed original typings & then low C & DQ to see if all sibs matched. We discovered 1 sib had antigen MM at DQ. Conclusions: Overall, we concluded that the ultimate benefit would have been discovering DQ MM initially that would otherwise have been missed. Now, reconsidering approach to related BM Donors.
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PROSPECTIVE HEMATOPOIETIC STEM CELL RECIPIENT TYPING REVEALED AN INHERITED NOVEL DQB1 ALLELE – RAISING QUESTIONS FOR NMDP POTENTIAL DONOR SEARCHING. Runying Tian, Angelica DeOliveira, Gansuvd Balgansuren, Dong-Feng Chen. Department of Pathology and Clinical Laboratories, Duke University Medical Center, Durham, NC, USA. Aim: Increased novel allele discovery has a huge contribution to HLA diversity, which could, however, complicate donor search. Currently, no clear guidelines of unrelated hematopoietic stem cell (HSC) donor search are available when novel alleles are involved. Novel alleles raise questions of the clinical significance of the substitution and its effect on unrelated donor search. In this study we present an approach to evaluate a novel allele for donor search. Methods: HLA high resolution typing was performed by SBT. We examined the clinical significance of a novel DQB1⁄06:XX allele for the difference between it and the common DQB1⁄06:02, the nature of the changed amino acid, and the location of the changed amino acid on three dimensional structure (a helix or b sheet). Results: DQB1 high resolution typing revealed a novel allele identical to DQB1⁄06:02 with except for a mismatch at position 25 within exon 2. The Nucleotide changed from ‘G’ to ‘T’ which caused amino acid changing from Glycine to Valine at codon 13(b13) in the amino-terminal region. The mutation is located on the floor of groove accommodating anchor position pocket 4 (P4). The side group of Glycine in DQB1⁄06:02 changed from –H to –C3H7 for Valine in novel DQB1⁄06:XX. The replaced side group –C3H7 occupies more space and possesses more hydrogen bonds. Although the shape and affinity of the peptide binding pocket might be altered due to changing of the side chain, both Valine and Glycine still belong to hydrophobic amino acid group. High resolution HLA typing of his mother and three siblings were also performed. The novel allele was inherited from the mother. Conclusions: Our findings suggest that the amino acid change of the novel allele DQB1⁄06:XX might not be clinically significant based on its location and characteristics when compared to the common DQB1⁄06:02. The method we used to evaluate a novel allele could be a practical approach for the unrelated donor search for a potential HSC recipient with a novel allele of any loci.
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A ‘‘NEW’’ APPROACH TO RELATED BONE MARROW DONORS. Lynda Thompson, Linda McEneny. Histocompatibility Lab, McMaster University Medical Centre, Hamilton, ON, Canada. Aim: To investigate changing protocol for HLA typings on related Bone Marrow (BM) Donors. Current protocol: Recipient typed at low res with ABDRDQ kit. Siblings typed at low res with ABDR kit. Matched Donor at low prompts BM program to select donor for further testing which initially includes high res DR for Recipient & Donor. If matched, low res C & high res A, B & C performed for matching pair. Methods: DNA extraction using manual salting-out extraction kit by Qiagen. PCR-SSP using low & high resolution primer kits by One Lambda & Olerup. Results: Typing performed on Recip: A⁄01,29,B⁄57,56,DRB1⁄07,01,B4⁄,DQB1⁄02,05. Typings on 3 sibs all resulted in matches at low res ABDR. Donor selection made by BM program, we proceeded with high DR typing to confirm match. Confirmed DRB1⁄07:01, 01:02, followed by low C typing: results C⁄06,16. Performed high res A, B & C for Recipient & Donor. Questioned likelihood of 4 sibs matching at all loci. Unlikely frequency, prompted (outside protocol) high DR on other 2 siblings. Two sibs matched at high DRB1. For education, we confirmed original typings & then low C & DQ to see if all sibs matched. We discovered 1 sib had antigen MM at DQ. Conclusions: Overall, we concluded that the ultimate benefit would have been discovering DQ MM initially that would otherwise have been missed. Now, reconsidering approach to related BM Donors.
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PROSPECTIVE HEMATOPOIETIC STEM CELL RECIPIENT TYPING REVEALED AN INHERITED NOVEL DQB1 ALLELE – RAISING QUESTIONS FOR NMDP POTENTIAL DONOR SEARCHING. Runying Tian, Angelica DeOliveira, Gansuvd Balgansuren, Dong-Feng Chen. Department of Pathology and Clinical Laboratories, Duke University Medical Center, Durham, NC, USA. Aim: Increased novel allele discovery has a huge contribution to HLA diversity, which could, however, complicate donor search. Currently, no clear guidelines of unrelated hematopoietic stem cell (HSC) donor search are available when novel alleles are involved. Novel alleles raise questions of the clinical significance of the substitution and its effect on unrelated donor search. In this study we present an approach to evaluate a novel allele for donor search. Methods: HLA high resolution typing was performed by SBT. We examined the clinical significance of a novel DQB1⁄06:XX allele for the difference between it and the common DQB1⁄06:02, the nature of the changed amino acid, and the location of the changed amino acid on three dimensional structure (a helix or b sheet). Results: DQB1 high resolution typing revealed a novel allele identical to DQB1⁄06:02 with except for a mismatch at position 25 within exon 2. The Nucleotide changed from ‘G’ to ‘T’ which caused amino acid changing from Glycine to Valine at codon 13(b13) in the amino-terminal region. The mutation is located on the floor of groove accommodating anchor position pocket 4 (P4). The side group of Glycine in DQB1⁄06:02 changed from –H to –C3H7 for Valine in novel DQB1⁄06:XX. The replaced side group –C3H7 occupies more space and possesses more hydrogen bonds. Although the shape and affinity of the peptide binding pocket might be altered due to changing of the side chain, both Valine and Glycine still belong to hydrophobic amino acid group. High resolution HLA typing of his mother and three siblings were also performed. The novel allele was inherited from the mother. Conclusions: Our findings suggest that the amino acid change of the novel allele DQB1⁄06:XX might not be clinically significant based on its location and characteristics when compared to the common DQB1⁄06:02. The method we used to evaluate a novel allele could be a practical approach for the unrelated donor search for a potential HSC recipient with a novel allele of any loci.
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