#23
THE NEW NETCORD MATCHING PROGRAM.
Juergen Enczmann , Peter Wernet and Pablo Rubinstein . D
sseldorf Germany, Universityclinic Dsseldorf, 40225, ITZ and New York NY, New York Blood Center, 10021, Laboratory of Immunogenetics .
One problem in the search for the best HLA-matched CBs for a given patient is the heterogeneity of the HLA-data in the databases. Another problem is the definition of a match, which might change in the future. Therefore, a flexible system is needed which is able to compare HLA-data from different sources. NETCORD decided to use search determinants (SD) to translate HLA-data from serology and DNA-based typing into a common language.Actual matches for HLA-A and –B are based at low resolution level and for HLA-DRB1 are based at high resolution level. If it is not possible to decide whether there is a match not, NETCORD calls this combination a potential match (e.g. A9 vs. A23). 
Figure 1 shows an schematic outline of the search process. The HLA-data of a patient are translated into SDs using a table which defines a SD for every known HLA-type. Another table is used to translate the HLA-type of the CBs into SD with actual or potential matches.
The sum of actual and potential matches is called the match level. The CBs are sorted first according to the match level. Cbs with the same match level are then sorted according to the actual matches and then according to the total number of nucleated cells. The table below shows an example of this ranking. HLA-A,B HLA-DR actual matches pot. matches cell count Ranking Patient A25,19 B44,38 *1501,*0101 CB1 A25,30 B44,38 *1501,*0101 5 1 100 1 CB2 A10,30 B44,38 *1501,*0101 4 2 100 2 CB3 A25,30 B44,38 *15,*01 3 3 100 3