1. ¹Department of Medicine I, Bone Marrow Transplantation, Medical University of Vienna, Austria
2. ²Department of Blood Group Serology, Medical University of Vienna, Austria
3. ³Institute of Medical Statistics and Documentation, University of Vienna, Austria
4. ⁴Austrian Bone Marrow Donor Registry, Vienna, Austria

Correspondence: Dr HT Greinix, AKH Wien, Klinik fuer Innere I, Knochenmarktransplantation, Waehringer Guertel 18-20, A-1090 Vienna, Austria. E-mail: hildegard.greinix@meduniwien.ac.at

Received 16 July 2004; Accepted 17 September 2004; Published online 8 November 2004.

Abstract

There is consensus that matching of unrelated donors (URD) and patients for HLA class II alleles improves the outcome of hematopoietic stem cell transplantation (HSCT). However, the significance of HLA class I allelic mismatches for transplant outcome is under discussion and reports on long-term effects like chronic graft-versus-host disease (GVHD) are rare. Thus, we investigated the association of human leukocyte antigen (HLA) class I allele mismatches and outcome in 144 patients given HSCT from URD who were matched for HLA-DRB1, DRB3/4/5, and DQB1 alleles. The risk of chronic GVHD was significantly increased in patients with class I mismatched donors, the mismatch either detected by low- or high-resolution typing. A single HLA class I allele mismatch significantly increased the risk of chronic GVHD in multivariate analysis. Overall survival was significantly reduced in patient/donor pairs with more than one-allele class I mismatch. Thus, selection of unrelated donors for transplantation should be based on high-resolution HLA class I typing.