Multiplex single nucleotide extension: a robust and high throughput method for HLA-A locus typing

Polymorphisms of human leucocyte antigen genes in Maonan people in China

We examined human leucocyte antigen (HLA) gene polymorphisms in the Maonan people from southern China. HLA‐A, ‐B and ‐DRB1 alleles were determined in 108 healthy unrelated Maonan individuals by the polymerase chain reaction‐Luminex method, and haplotype frequencies for HLA‐A, ‐B and ‐DRB1 loci were estimated. The most frequent HLA‐A alleles were A*1101 (35.2%), A*0203 (17.6%), A*0207 (13.4%) and A*2402 (13.4%); HLA‐B alleles were B*1301(19.9%), B*1502 (14.8%), B*4601 (13.4%) and B*4001 (13.4%); HLA‐DRB1 alleles were DRB1*1202 (17.1%), DRB1*1602 (13.0%) and DRB1*1401 (10.7%). The most common haplotypes were A*0207‐B*4601 (10.6%), A*1101‐B*1301 (10.0%), A*1101‐B*4001 (8.4%), B*1502‐DRB1*1202 (12.0%), B*4601‐DRB1*1401 (5.8%), A*1101‐B*1502‐DRB1*1202 (7.1%) and A*0207‐B*4601‐DRB1*1401 (5.3%), profiles that are also found in populations from the southern region of East Asia. Phylogenetic and principal component analyses revealed that the Maonan people belong to the southeastern Asian group and are most closely related to the Buyi people.

Real-Time PCR Using Fluorescent Resonance Emission Transfer Probes for HLA-B Typing

HLA genotyping by polymerase chain reaction (PCR) has some inherent labor-intensive and effort-demanding limitations. To overcome them, we have developed a real-time PCR with hybridization probes approach able to obtain a medium-low resolution HLA-B genotyping with fewer tubes and probes and with a shorter time requirement. Our strategy used 18 simultaneous reactions amplifying HLA-B alleles and an internal control. Monitorization of both amplifications in each tube is performed by the simultaneous application of two fluorescent resonance emission transfer probes: the first probe, different for each tube, is specific for the HLA-B locus and the second probe detects the control gene. A medium-low resolution (300 HLA-B allelic groups) typing is obtained for each sample by analyzing the melting curve patterns. Because some alleles may be determined without using the complete set of reactions, we present an alternative strategy: a first round of seven reactions and, according to the result, a second (or third) round of PCRs to solve the ambiguities. This method was validated in pretyped clinical samples and the results were completely concordant. Moreover, fewer ambiguous results were obtained. In summary, we present a new, faster, and more accurate method than currently used PCR techniques to type HLA-B alleles.