Next Generation Sequencing Identifies the HLA-DQA1*03:03 Allele in the Type 1 Diabetes Risk-Associated HLA-DQ8 Serotype

The highest genetic type 1 diabetes risk is conferred by HLA class II haplotypes defined by alleles at the HLA-DR and -DQ loci. The combination of HLA-DQA1*03:01 and DQB1*03:02 alleles (summarized as ‘HLA-DQ8′) is reported to be among the two most prevalent HLA class II haplotypes in Caucasian type 1 diabetes patients. This classification is based on conventional genotyping of exon 2 of the DQ gene locus and excludes exon 3. In this study, HLA genotyping on the type 1 diabetes susceptibility loci HLA-DRB1, DQA1 and DQB1 was performed using a high-resolution next generation sequencing method. In addition to the routinely examined exon 2, exon 3 was also sequenced. Samples from 229 children with type 1 diabetes were included and compared to a cohort of 9,786 controls. In addition to previously described HLA-DQ haplotypes in type 1 diabetes patients, we found that as well as HLA-DQA1*03:01,HLA-DQA1*03:03 also contributed to HLA-DQ8. HLA-DQA1*03:03 differs from HLA-DQA1*03:01 by one nucleotide substitution in exon 3 at position 160, leading to a single amino acid replacement. DRB1*04:05 was exclusively associated with DQA1*03:03 whereas the DRB1*04:01 haplotype comprised either DQA1*03:01 or DQA1*03:03. Significantly increased type 1 diabetes risk was confirmed for all these haplotypes with only minor differences between DQA1*03:01 and DQA1*03:03 alleles. This study identified the HLA-DQA1*03:03 allele as an addition to the already known type 1 diabetes risk haplotypes, and can contribute to more precise HLA genotyping approaches.

A New Human Leukocyte Antigen Typing Algorithm Combined With Currently Available Genotyping Tools Based on Next-Generation Sequencing Data and Guidelines to Select the Most Likely Human Leukocyte Antigen Genotype

BackgroundHigh-precision human leukocyte antigen (HLA) genotyping is crucial for anti-cancer immunotherapy, but existing tools predicting HLA genotypes using next-generation sequencing (NGS) data are insufficiently accurate.Materials and MethodsWe compared availability, accuracy, correction score, and complementary ratio of eight HLA genotyping tools (OptiType, HLA-HD, PHLAT, seq2HLA, arcasHLA, HLAscan, HLA*LA, and Kourami) using 1,005 cases from the 1000 Genomes Project data. We created a new HLA-genotyping algorithm combining tools based on the precision and the accuracy of tools’ combinations. Then, we assessed the new algorithm’s performance in 39 in-house samples with normal whole-exome sequencing (WES) data and polymerase chain reaction–sequencing-based typing (PCR-SBT) results.ResultsRegardless of the type of tool, the calls presented by more than six tools concordantly showed high accuracy and precision. The accuracy of the group with at least six concordant calls was 100% (97/97) in HLA-A, 98.2% (112/114) in HLA-B, 97.3% (142/146) in HLA-C. The precision of the group with at least six concordant calls was over 98% in HLA-ABC. We additionally calculated the accuracy of the combination tools considering the complementary ratio of each tool and the accuracy of each tool, and the accuracy was over 98% in all groups with six or more concordant calls. We created a new algorithm that matches the above results. It was to select the HLA type if more than six out of eight tools presented a matched type. Otherwise, determine the HLA type experimentally through PCR-SBT. When we applied the new algorithm to 39 in-house cases, there were more than six matching calls in all HLA-A, B, and C, and the accuracy of these concordant calls was 100%.ConclusionsHLA genotyping accuracy using NGS data could be increased by combining the current HLA genotyping tools. This new algorithm could also be useful for preliminary screening to decide whether to perform an additional PCR-based experimental method instead of using tools with NGS data.

HLA-B*15:01 is associated with asymptomatic SARS-CoV-2 infection

Background. Evidence has shown that a large proportion of SARS-CoV-2 infected individuals do not experience symptomatic disease. Owing to its critical role in immune response, we hypothesized that variation in the human leukocyte antigen (HLA) loci may underly asymptomatic infection. Methods. We enrolled 29,947 individuals registered in the National Marrow Donor Program for whom high-resolution HLA genotyping data were available in a smartphone-based study designed to track COVID-19 symptoms and outcomes. Among 21,893 individuals who completed the baseline survey, our discovery (N=640) and replication (N=788) cohorts were comprised of self-identified White subjects who reported a positive test result for SARS-CoV-2. We tested for association of five HLA loci (HLA-A, -B, -C, -DRB1, -DQB1) with asymptomatic vs. symptomatic infection. Results. HLA-B*15:01 was significantly increased in asymptomatic individuals in the discovery cohort compared to symptomatic (OR = 2.45; 95%CI 1.38-4.24, p = 0.0016, pcorr = 0.048), and we reproduced this association in the replication cohort (OR= 2.32; 95%CI = 1.10-4.43, p = 0.017). We found robust association of HLA-B*15:01 in the combined dataset (OR=2.40 95% CI = 1.54-3.64; p = 5.67 x10-5) and observed that homozygosity of this allele increases more than eight times the chance of remaining asymptomatic after SARS-CoV-2 infection (OR = 8.58, 95%CI = 1.74-34.43, p = 0.003). Finally, we demonstrated the association of HLA-B*15:01 with asymptomatic SARS-Cov-2 infection is enhanced by the presence of HLA-DRB1*04:01 Conclusion. HLA-B*15:01 is strongly associated with asymptomatic infection with SARS-CoV-2 and is likely to be involved in the mechanism underlying early viral clearance.

The deleterious effect of the HLA-C1/KIR2DL3 receptor-ligand combination in Chinese HIV patients

Background The combination of KIR-HLA affects the prognosis of HIV infection, and polymorphisms of KIR and its ligand HLA differs between regions and races. Few research has focused on the effects of the KIR-HLA combination on the prognosis of HIV-infected individuals in China. Methods Peripheral blood samples were collected from newly diagnosed and treatment naïve HIV-infected patients and processed according to the study design. Their clinical data and other demographic information were recorded. The genomic DNA of the host was extracted from whole blood samples, and KIR genotyping was performed using sequence specific primer amplification (PCR-SSP). The HLA genotyping was performed using sequence analysis (PCR-SBT), and the HLA-KIR genotyping and combination information were obtained. Fisher’s exact test was used for the comparison of categorical variables between groups, and the Mann-Whitney test was used for continuous variables. Results The baseline HIV level in patients with an HLA-C1+/KIR2DL3+ background was significantly higher than that in patients with an HLA-C1+/KIR2DL3- (4.34 log10 copies/ml vs. 3.72 log10 copies/ml, P=0.02). The baseline CD4/CD8 ratio of HLA-C1+/KIR2DL3+ patients was significantly lower than that of HLA-C1+/KIR2DL3- patients (0.33 vs. 0.56, P=0.02). The plasma soluble CD14 level at baseline was significantly lower in HLA-C1+/KIR2DL3- infected persons than HLA-C1+/KIR2DL3+ patients (P=0.03). Conclusions HIV-infected persons with the combination of HLA-C1+/KIR2DL3+ had a much higher HIV set point, higher baseline sCD14 levels and lower baseline CD4/CD8 than patients without this combination. The receptor-ligand combination of HLA-C1+/KIR2DL3+ has a deleterious effect in Chinese HIV patients.