P107 Next generation sequencing (NGS) of the MHC, in Mestizos from Oaxaca, belonging to the Mexican unrelated donor registry-DONORMO

Introduction NGS allows the generation of a large number of clonal sequences in a single run. We can handle the tight MHC Δ between genes, polymorphism and heterozygosity. We showed a non-homogenous combination of Amerindian, Caucasian and African genes in Mestizos, depending upon the region. Oaxaca, is additionally, admixed with 18 Native local groups. Methods 197 donors from Oaxaca, registered at DONORMO were chosen. HLA typing was achieved by amplification by long range PCR with full gene coverage for class I loci and large coverage of class II loci including all exons with exception of exon-2. All amplicons for each sample were pooled and tagged for sequencing and sample identification; 24 samples at a time were pooled and sequenced with an Illumina Miseq instrument. Analyses of sequences was determined by the application of ad hoc develop programs that utilized three logic components including mapping of sequences to references and by performing full assembly. With exception of DPB1, genotypes at all loci, were assigned unambiguously. Allele (AF) and (HF) frequencies were assessed with the Arlequin 3.5.1.2. Results We show here some prevalent alleles (AF > 6%): A ∗ 02:01:01, ∗ 24:02:01:01; B ∗ 39:05:01e,39:02:02e1(AF > 8%); C ∗ 07:02:01:01, ∗ 04:01:01:01(AF > 18%); DRB1 ∗ 04:07:01, ∗ 08:02:01, ∗ 16:02:01e2(AF > 7%); DRB3 ∗ 02:02:01:02, ∗ 01:01:02e3(AF > 20%); DRB4 ∗ 01:03:01:01, ∗ 01:03:01:01/03(AF = 25%); DRB5 ∗ 02:02e, ∗ 01:01:01e1(AF > 20%); DQA1 ∗ 03:01:01, ∗ 04:01:01e- IV(AF > 9%); DQB1 ∗ 03:02:01, ∗ 03:01:01 (AF > 13%); DPA1 ∗ 01:03:01:05, ∗ 01:03:01:02(AF > 24%); DPB1 ∗ 04:02:01:02, ∗ 04:01:01:01; ∗ 04:02:01:02-IV, (AF > 10%). Of 3516 A ∗ -B ∗ -C ∗ -DRB1 ∗ -DQB1 ∗ -DQA1 ∗ haplotypes ( > 1.5%): 68:03-39:05-07:02-04:07-03:02-03:01; 02:01-39:02-07:02-04:07-03:02-03:01 and of 1184 DRB1 ∗ -DQB1 ∗ -DQA1-DPB1 ∗ -DPA1 ∗ : 04:07-03:02-03:01-04:02;01-03; 08:02-04:02-04:01-04:02-01;03, prevailed. Conclusions Analyzing the whole gene, will lead to a better understanding of the role of HLA in transplantation and disease and NGS brings about less ambiguities. Some issues will be solved establishing a complete database of HLA alleles and will overcome the present errors in assembling single reads to allelic sequences. Many allele frequency estimation errors exist in population frequencies that NGS will clarify, as shown in this group. M. Mindrino : Employee; Company/Organization; President . M. Fernandez-Vina : Consultant; Company/Organization; NGS .