A novel method for KIR-ligand typing by pyrosequencing to predict NK cell alloreactivity.

Studies have shown that KIR-ligand mismatching to predict NK cell alloreactivity may result in less relapse and better survival in patients with AML. KIR-ligands are distinguished by single nucleotide polymorphisms (SNPs) from HLA-B and HLA-C sequences. We hypothesized that pyrosequencing to determine KIR-ligand status by direct sequencing of the ligand epitope can be done as an alternative to high-resolution HLA-typing. Pyrosequencing is rapid and would be particularly useful in analysis of retrospective cohorts where high-resolution HLA-typing is unavailable or too expensive. To validate this assay, RNA and DNA from 70 clinical samples were tested for KIR-ligand by pyrosequencing. Primer binding to invariant regions without known SNPs was critical for KIR-ligand assignment by pyrosequencing to be in full concordance with high-resolution HLA-typing. Pyrosequencing is sensitive, specific, high-throughput, inexpensive, and can rapidly screen KIR-ligand status to evaluate potential alloreactive NK cell or transplant donors.