Search Determinants

HLA Allele and Serologic Specificity Search Determinant Assignments

Registries and cord blood banks around the world collect and store HLA typing information for volunteer donors that is used to identify matched unrelated donors for patients requiring hematopoietic stem cell transplantation. This is a formidable task requiring databases that can accomodate the many formats in which HLA types are provided by the testing laboratories (types obtained by serology testing and testing by DNA-based methods at either low, intermediate or high resolution). As a result of this diversity, intricate systems need to be developed that can identify which of these diverse types are most likely to match the HLA assignments of a searching patient. Conversion of the HLA assignments to "search determinants" is one approach that may be included within the algorithm used to select and prioritize a list of potentially suitable donors within large donor data files. The strategies used by registries to create search determinants are discussed in the following manuscript:

Hematopoietic Stem Cell Donor Registry Strategies For Assigning Search Determinants And Matching Relationships
Carolyn K. Hurley, et.al., Bone Marrow Transplantation (2004) 33(4):443-450

The following tables detail HLA locus specific sets of serologic and DNA allele search determinants that are currently used by the National Marrow Donor Program^®. The HLA-A and HLA-B allele search determinant assignments are based on serologic relationships between the alleles and corresponding antigens. The HLA-DRB1 allele search determinants are based on DNA nomenclature.

The allele set used for the following tables (July 2003 IMGT/HLA Sequence Database release 2.2.0) was from the World Health Organization (WHO) Nomenclature Committee for Factors of the HLA System*. The search determinant tables for DNA alleles will be periodically updated as new HLA alleles are described in subsequent IMGT/HLA Sequence Database releases.

Questions or comments about the search determinants can be sent by e-mail to: search-determinants@nmdp.org.

*Robinson J, Malik A, Parham P, Bodmer JG, and Marsh SGE. 2000. IMGT/HLA database--sequence database for the Human Major Histocompatibility Complex. Tissue Antigens 55:280-287.

*Marsh SGE, Albert ED, Bodmer WF et al. 2002. Nomenclature for factors of the HLA system, 2002. European Journal of Immunogenetics 29:463-515.