Assignment of HLA-DPB alleles by computerized matching based upon sequence data.

Routine HLA typing by serology has been supported by DNA or protein analysis of the respective molecules in cases when serologic typing was inconclusive or difficult to perform. DNA analysis by RFLP, SSO, or PCR amplification with SSP is a reliable tool for the identification of alleles. Because DNA sequences may now be determined routinely, we developed software based on sequence data from known sequences for allele assignment of polymorphic gene systems. We describe the assignment of HLA-DPB alleles based upon sequence data obtained after PCR amplification and subsequent sequencing of exon 2. Our software includes a database containing all known HLA-DPB sequences, which offers the possibility of analyzing heterozygous individuals by combinatorial comparison through all alleles and thus identifying the one or two alleles involved. Quality control of the sequence has been included by the alignment of constant regions of the sequence combined with related polymorphism of known polymorphic nucleotides and the identification of the positions crucial for the allele assignment. The ability to type for HLA-DPB alleles routinely by automatic sequence determination and subsequent automated analysis offers new perspectives for HLA-DNA typing.