NCBI SEMINAR ANNOUNCEMENT:
June 1, 11:00, 8th floor conference room, Bldg 38A, NIH

Dr. Wolfgang Helmberg.

Dr. Helmberg is the leading candidate for an NCBI position of local curator of
HLA data, and he will be the NCBI point man for coordinating the data produced
by the 13th International Histocompatibility Working Group.

TITLE:
"Virtual DNA Analysis- a tool for correct utilisation and storage of DNA typing
data of highly polymorphic loci such as HLA."

ABSTRACT:
HLA typing is an essential part of clinical diagnostics within several fields,
e.g. bone marrow transplantation. HLA serology has already revealed that the
different HLA loci are highly polymorphic. The introduction of DNA typing
techniques has increased further the rate of discovery of new HLA alleles with
over 1150 alleles described to date. DNA typing in routine laboratories relies
mainly on the hybridisation with sequence specific oligonucleotides (SSO) or
amplification with sequence specific primers (SSP). In order to report a result
generated using these methods, the typings have been interpreted as possible
allele combinations, which have subsequently been stored in a summarised way.
Such handling of data has caused a serious loss of information and proved to be
incapable of handling newly detected alleles.

Virtual DNA Analysis (VDA) has been developed as tool to deal with these
problems. The concept is based on the target DNA recognised by the respective
typing techniques. All SSO/SSP or sequencing based typing (SBT) results are
stored as a virtual sample DNA without loss of information. Evaluation of
generic or allele specific DNA typing or the combination of both is supported.
Due to this flexible approach, all kinds of SSO/SSP typing sets, as far as the
respective SSO/SSP nucleotide sequences are available, can be entered and
re-evaluated at any time with an updated allele database.

The application of VDA in the European cell exchanges of 1998 and 1999
demonstrated the feasibility of exchange of raw DNA typing data rather than of
the interpreted typing results. These cell exchanges have also demonstrated the
necessity and have been the initiation of a central SSO/SSP database in order to
facilitate exchange of such DNA typing data. Currently a pilot project is in
preparation for the 13th International Histocompatibility Workshop which will
take place in 2001, to assess the wide scale use of this approach. The
application of VDA for bone marrow donor registries is in evaluation.