VIRTUAL DNA ANALYSIS (VDA) - FIRST EXPERIENCE WITH A SEQUENCE BASED DATABASE AND EVALUATION SYSTEM.
W. Helmberg°, G. Lanzer°, R. Zahn⁺, B. Weinmayr°, T. Wagner°, E. Albert⁺, °Transfusionmedicine, Universityclinics, Graz, Austria, ⁺Laboratory for Immunogenetics, LMU Munich, Germany.


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Virtual DNA Analysis is based on the storage of single DNA-sequence information (Helmberg et al, Tissue Antigens, in press) instead of storage of the interpretation of HLA typing results. This allows the combined storage and evaluation of SSP, SSO and SBT results. We have used this evaluation system in two labs over half a year for routine laboratory data evaluation and storage. During this time HLA typings of the loci A, B, C, DRB and DQB were performed. Test kits used were home made (SSO, DRB), Elpha(SSO, Biotest, DRB), Inno-lipa (SSO, Innogenetics, DRB), Roche-Amplicor(SSO, Roche, DRB), and Dynal (SSP, Dynal, A,B,C, DRB low and high resolution, DQB). In some cases SBT results were added (ABI). The target sequences detected by the different typing kits were either taken from the kit information or supplied by the companies. During the data entry of the single SSO/SSP sequences we were able to detect several errors in the interpretation tables, either due to false specifications of SSO/SSPs or due to incomplete listing of allele reactivities. All SSO/SSP or SBT results were transformed to a virtual sample DNA, which subsequently was analysed. The combination of collected data of different typing sets and procedures lead to the highest possible typing resolution. The allele database has been updated twice within this time. The storage of the acquired single typing reactivities made it possible to reanalyse the typings with the updated database. We regard the principle of Virtual DNA Analysis as a use- and helpful tool for routine HLA typing laboratories.