#17
ON THE RELEVANCE OF HLA CLASS I ALLELE LEVEL MATCHING FOR UNRELATED STEM CELL DONOR TRANSPLANTS IN GERMANY.
Carlheinz R. Müller M.D., Ph.D. 1, Kaimo Hirv M.D. 2, Shraga F. Goldmann M.D. 2 and Klaus Schwarz M.D. 2. 1 ZKRD, Zentrales Knochenmarkspender-Register Deutschland, Ulm, Germany and 2 Inst of Clin Tranfusion Medicine and Immunogenetics, RC BTS Baden-Württemberg-Hessen, Ulm, Germany .
The German Consensus for matching allogeneic donors of hematopoietic progenitor cell (1996/2000) recommends matching donors for HLA-A,B on serological level (2 digit allele level matching within split groups for B15, B40) and by allele level for DRB1 and, if possible, DQB1. We have retrospectively performed sequencing based HLA-A,B,C analyses for 262 adult unrelated donor recipient pairs matching for A, B and DRB1 according to the above definition in order to see if outcome could be improved by more stringent selection criteria. Accepted diagnoses were ALL (21%), AML (39%), CML (33%) and MDS (7%). 60% of the patients were male with a median age of 38 (range 18-67) whereas 67% of the donors were male with a median age of 36 (range 19-58). The patients were transplanted in Berlin (56), Erlangen(6), Hannover (9), Heidelberg (18), Mainz (56), Munich (50), Regensburg (13), Ulm (11), Wiesbaden (43) using heterogeneous regimens for conditioning and GvHD-prophylaxis. After analyzing the relevant covariates we stratified the Cox proportional hazard model for patient age (<> median), diagnosis and disease phase (early 145, advanced 117). We found 20 pairs with an allele level difference for A, 43 for B, 112 for C and 20 for DQB1. The only significant detrimental effect for survival was seen for allele level differences of HLA-B with R=1.56 (1.01 
2.41) and p <.05. The survival curves did not suggest an influence of any other HLA difference mentioned except for advanced disease where allele differences of HLA-A or C may be beneficial probably due to a GvL effect.
Study supported by the German Jos
Carreras Leukemia Foundation.