HLA typing using bead-based methods.

The LABType(®) SSO (One Lambda, Inc) and Gen-Probe LIFECODES HLA-SSO HLA Typing tests are rapid and efficient assays for determining human leukocyte antigens (HLAs). The principle of these assays involves the hybridization of reverse sequence-specific oligonucleotide probes each attached to a unique colour coded microsphere to identify HLA class I and class II alleles. Target DNA is polymerase chain reaction (PCR) amplified using group-specific primers and then biotinylated which allows it to be detected using R-Phycoerythrin-conjugated Streptavidin. The PCR product is then denatured and allowed to hybridise to complementary DNA probes conjugated to fluorescently code microsperes. The Luminex(®) Flow Analyser achieves detection by determining the fluorescent intensity of PE on each microsphere. The assignment of HLA alleles is based on the reaction pattern of the various beads compared to patterns with known HLA alleles.