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#22
MOLECULAR HLA TYPING BY SSP OF BONE MARROW RECIPIENTS AND DONORS.
Robert E. Cirocco , Carmen Gomez , George W. Burke , Esquenazi Violet and Miller Joshua . Miami FL, University of Miami and the Veterans Affairs Administration Hospital, 33133, Surgery/Transplant .

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Hemeatopoeitic reconstitution of related or matched unrelated bone marrow is the treatment of choice, after recipient myloablation, for most leukemia’s. The National Marrow Donor Programs’ current matching criteria is to match at low resolution for Class I (HLA-A and HLA-B) and high resolution for DRB1. We compared molecular HLA typing methods ; Sequence Specific Oligo probe hybridization (SSOP), sequencing, and Sequence Specific Priming (SSP). Our center has been using the SSP assays (One Lambda, Canoga Park, CA) for this molecular HLA typing. Initially a low-resolution ABC tray and a DRB1/DQB1 tray is used to determine the class I and II group specificity for these HLA loci. This is followed by an allelic resolution tray, which in most cases resolves the group to a specific DRB1 allele. We tested 64 individuals with SSP and sent out the same samples to a reference lab for SSP, SSOP typing, and sequencing. We compared our SSP results to the outside labs results and there was 100% agreement. All HLA-And HLA-B typings were concordant. There were two primer pairs in the allele level kits that gave multiple allele possibilities The two primers were for the DRB1* 0301/19-20 (N=4, all *0301) and DRB1* 1501/12-13 alleles (N=2, all*1501). The primer pairs could not distinguish these differences and the DNA in question must be sequenced to the allelic level. The new lots have solved this problem. In conclusion, using SSP typing for class I and Class II alleles in potential bone marrow donors and recipients is accurate, less labor intensive, and less costly than other methods. The SSP procedure allows all labs, large and small, an alternative to SSOP and Sequencing for the analysis and matching of HLA alleles in Bone Marrow transplantation.