Immunogenetics experts at The Children’s Hospital of Philadelphia (CHOP) have developed a laboratory test to characterize the genes that encode HLA molecules. The test relies on comprehensive gene sequencing technology to type human leukocyte antigens (HLAs)—highly variable proteins on cell surfaces that are essential to immune function.
The new test may improve transplantation outcomes through a more refined assessment of donor compatibility and may expedite the donor selection process from bone marrow registries. It also provides an advanced tool for research in immunological diseases, infectious diseases, and pharmacogenomics. CHOP will offer the HLA typing test for patient testing as a service to medical and academic centers.
HLA genes are the most complex gene family known in the human genome. Gene sequences for HLAs are highly variable. CHOP spokespersons say that current tests often provide ambiguous and limited results by sequencing only segments of HLA genes and failing to distinguish among different alleles suggested by a given sequence. Preliminary testing also often must be followed by a second level of reflexive testing, adding expense and time to the HLA typing process.
According to Dimitri Monos, PhD, director of CHOP's Immunogenetics Laboratory, the new test replaces preliminary are reflexive tests with a single test, covering the full HLA genomic region. It can currently distinguish among 10,500 different alleles of all known HLA types and can fully characterize new alleles yet to be discovered. Monos and colleagues developed a new protocol for HLA genotyping using an Illumina sequencing platform, the MiSeq. The scientists validated the test by comparing its results against previously sequenced data from a collection of more than 300 samples characterized at five different genes. The agreement between the two methodologies was 100%. Learn more about specialties and services provided by CHOP.
