The Immuno Polymorphism Database (IPD) plays a pivotal role for immunogenetics. Due to technical limitations, genotyping often focuses on specific key regions like the antigen recognition domain (ARD) for HLA genotyping, and the databases are populated accordingly. More recently, though, modern next generation sequencing (NGS) assays allow using larger gene segments or even complete genes for genotyping.
View Article and Find Full Text PDFThe prerequisite for successful HLA genotyping is the integrity of the large allele reference database IPD-IMGT/HLA. Consequently, it is in the laboratories' best interest that the data quality of submitted novel sequences is high. However, due to its long and variable length, the gene HLA-DRB1 presents the biggest challenge and as of today only 16% of the HLA-DRB1 alleles in the database are characterized in full length.
View Article and Find Full Text PDFOptimizing natural killer (NK) cell alloreactivity could further improve outcome after allogeneic hematopoietic cell transplantation (alloHCT). The donor's Killer-cell Immunoglobulin-like Receptor (KIR) genotype may provide important information in this regard. In the past decade, different models have been proposed aiming at maximizing NK cell activation by activating KIR-ligand interactions or minimizing inhibitory KIR-ligand interactions.
View Article and Find Full Text PDFPatients in need of hematopoietic stem cell transplantation often rely on unrelated stem cell donors matched in certain human leukocyte antigen (HLA) genes. Donor search is complicated by the extensive allelic variability of the HLA system. Therefore, large registries of potential donors are maintained in many countries worldwide.
View Article and Find Full Text PDFImmunogenetic association studies may give rise to new hypotheses on the immune surveillance of cancer. We hypothesized that certain combinations of killer immunoglobulin-like receptor (KIR) and HLA genotypes may enhance natural killer (NK) cell immunity against nascent acute myeloid leukemia (AML) and, thereby, lead to a skewed genotype distribution among patients. For this purpose, we analyzed KIR and HLA genotypes of 1767 German patients with AML and compared the results with that of the data of 51 890 German volunteers who had registered with German bone marrow donor file (DKMS).
View Article and Find Full Text PDFMany stem cell donor registries determine the cytomegalovirus (CMV) IgG serostatus at donor recruitment as it is an important marker for donor selection in the context of hematopoietic stem cell transplantation. To make sample collection less uncomfortable for the donor, we have developed a method that allows CMV status determination from buccal swab samples, thus avoiding blood drawing. However, the determination fails in some cases which leads to new donors being listed for donor search without CMV status, thus hindering donor searches.
View Article and Find Full Text PDF[This corrects the article DOI: 10.3389/fimmu.2020.
View Article and Find Full Text PDFWe estimated HLA haplotype frequencies based on individuals homozygous for 4, 5 or 6 loci. Validation of our approach using a sample of over 3.4 million German individuals was successful.
View Article and Find Full Text PDFHLA molecules are key restrictive elements to present intracellular antigens at the crossroads of an effective T-cell response against SARS-CoV-2. To determine the impact of the genotype on the severity of SARS-CoV-2 courses, we investigated data from 6,919 infected individuals. HLA-A, -B, and -DRB1 allotypes grouped into HLA supertypes by functional or predicted structural similarities of the peptide-binding grooves did not predict COVID-19 severity.
View Article and Find Full Text PDFThe killer-cell immunoglobulin-like receptor (KIR) complex on chromosome 19 encodes receptors that modulate the activity of natural killer cells, and variation in these genes has been linked to infectious and autoimmune disease, as well as having bearing on pregnancy and transplant outcomes. The medical relevance and high variability of KIR genes makes short-read sequencing an attractive technology for interrogating the region, providing a high-throughput, high-fidelity sequencing method that is cost-effective. However, because this gene complex is characterized by extensive nucleotide polymorphism, structural variation including gene fusions and deletions, and a high level of homology between genes, its interrogation at high resolution has been thwarted by bioinformatic challenges, with most studies limited to examining presence or absence of specific genes.
View Article and Find Full Text PDFBackground: High resolution HLA genotyping of donors and recipients is a crucially important prerequisite for haematopoetic stem-cell transplantation and relies heavily on the quality and completeness of immunogenetic reference sequence databases of allelic variation.
Results: Here, we report on DR2S, an R package that leverages the strengths of two sequencing technologies-the accuracy of next-generation sequencing with the read length of third-generation sequencing technologies like PacBio's SMRT sequencing or ONT's nanopore sequencing-to reconstruct fully-phased high-quality full-length haplotype sequences. Although optimised for HLA and KIR genes, DR2S is applicable to all loci with known reference sequences provided that full-length sequencing data is available for analysis.
Objectives: To determine the impact of the 32 bp deletion (CCR5Δ32) in the coding region of the C-C chemokine receptor 5 (CCR5) on the risk of contracting SARS-CoV-2 and severe COVID-19.
Methods: Cross-sectional study among stem cell donors registered with DKMS in Germany. Genetic information was linked to self-reported COVID-19 outcome data.
Results from registry studies suggest that harnessing Natural Killer (NK) cell reactivity mediated through Killer cell Immunoglobulin-like Receptors (KIR) could reduce the risk of relapse after allogeneic Hematopoietic Cell Transplantation (HCT). Several competing models have been developed to classify donors as KIR-advantageous or disadvantageous. Basically, these models differ by grouping donors based on distinct KIR-KIR-ligand combinations or by haplotype motif assignment.
View Article and Find Full Text PDFHLA-E is a member of the nonclassical HLA class Ib genes. Even though it is structurally highly similar to the classical HLA class Ia genes, it is less diverse and only 45 alleles and 12 proteins were known in December 2019 (IPD-IMGT/HLA, release 3.38.
View Article and Find Full Text PDFWe estimated HLA allele and haplotype frequencies of the Saudi Arabian population from a sample of 45,457 registered stem cell donors. The most frequent HLA alleles were A*02:01g (18.5%), C*06:02g (16.
View Article and Find Full Text PDFThe COVID-19 pandemic has serious implications also for patients with other diseases. Here, we describe the effects of the pandemic on unrelated hematopoietic stem cell donation and transplantation from the perspective of DKMS, a large international donor registry. Especially, we cover the development of PBSC and bone marrow collection figures, donor management including Health and Availability Check (HAC), transport and cryopreservation of stem cell products, donor recruitment and business continuity measures.
View Article and Find Full Text PDFTimely identification and isolation of affected individuals is one of the most important factors to control spreading of the newly emerged SARS-CoV-2. Consequently, it is crucial to maintain sufficient sample capacities in diagnostic laboratories. Here, we present a high-through-put approach for PCR-based SARS-CoV-2 testing.
View Article and Find Full Text PDFThe impact of the highly polymorphic Killer-cell immunoglobulin-like receptor () gene cluster on the outcome of hematopoietic stem cell transplantation (HCST) is subject of current research. To further understand the involvement of this gene family into Natural Killer (NK) cell-mediated graft-versus-leukemia reactions, knowledge of haplotype structures, and allelic linkage is of importance. In this analysis, we estimate population-specific haplotype frequencies at allele group resolution in a cohort of = 458 German families.
View Article and Find Full Text PDFMICA and MICB are ligands of the NKG2D receptor and thereby influence NK and T cell activity. gene polymorphisms, expression levels and the amount of soluble MICA/B in the serum have been linked to autoimmune diseases, infections, and cancer. In hematopoietic stem cell transplantation, matching between donor and patient has been correlated with reduced acute and chronic graft-vs.
View Article and Find Full Text PDFBackground: Buccal swab sampling constitutes an attractive noninvasive alternative to blood drawings for antibody serostatus assays. Here we describe a method to determine the cytomegalovirus immunoglobulin G (CMV IgG) serostatus from dried buccal swab samples.
Methods: Upon solubilization, CMV IgG is determined by an ELISA assay specifically adapted to cope with low IgG concentrations.