BSHI guideline: HLA matching and donor selection for haematopoietic progenitor cell transplantation.

A review of the British Society for Histocompatibility and Immunogenetics (BSHI) Guideline 'HLA matching and donor selection for haematopoietic progenitor cell transplantation' published in 2016 was undertaken by a BSHI appointed writing committee. Literature searches were performed and the data extracted were presented as recommendations according to the GRADE nomenclature.

Anti-N-methyl-d-aspartate receptor encephalitis in Maori and Pacific Island children in New Zealand.

AIM: To investigate the incidence and severity of anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis in children from New Zealand. METHOD: A retrospective case series was undertaken of all children (≤18y) diagnosed with anti-NMDA receptor encephalitis from January 2008 to October 2015. RESULTS: Sixteen patients were identified with anti-NMDA receptor antibodies in the cerebrospinal fluid, three of whom had an associated teratoma. Fifteen children had Maori and/or Pacific Island ancestry. The incidence of anti-NMDA receptor encephalitis in Maori children was 3.4 per million children per year (95% confidence interval [CI] 1.4-7.0) and the incidence in Pacific children was 10.0 per million children per year (95% CI 4.3-19.8) compared with 0.2 per million children per year (95% CI 0.0-1.0) in children without Maori or Pacific Island ancestry. Sixty-seven per cent of children had a good outcome (modified Rankin Score ≤2) at 2 years' follow-up. This compares unfavourably with other cohorts despite a shorter median time to first-line immunotherapy (13d; range 4-89) and a higher proportion of children being treated with second-line therapy (50%). INTERPRETATION: Maori and Pacific Island children have a higher incidence of anti-NMDA receptor encephalitis and possibly a more severe phenotype. These data suggest a genetic predisposition to anti-NMDA receptor encephalitis in these populations.

KIR diversity in Maori and Polynesians: populations in which HLA-B is not a significant KIR ligand.

HLA class I molecules and killer cell immunoglobulin-like receptors (KIR) form a diverse system of ligands and receptors that individualize human immune systems in ways that improve the survival of individuals and populations. Human settlement of Oceania by island-hopping East and Southeast Asian migrants started ~3,500 years ago. Subsequently, New Zealand was reached ~750 years ago by ancestral Maori. To examine how this history impacted KIR and HLA diversity, and their functional interaction, we defined at high resolution the allelic and haplotype diversity of the 13 expressed KIR genes in 49 Maori and 34 Polynesians. Eighty KIR variants, including four 'new' alleles, were defined, as were 35 centromeric and 22 telomeric KIR region haplotypes, which combine to give >50 full-length KIR haplotypes. Two new and divergent variant KIR form part of a telomeric KIR haplotype, which appears derived from Papua New Guinea and was probably obtained by the Asian migrants en route to Polynesia. Maori and Polynesian KIR are very similar, but differ significantly from African, European, Japanese, and Amerindian KIR. Maori and Polynesians have high KIR haplotype diversity with corresponding allotype diversity being maintained throughout the KIR locus. Within the population, each individual has a unique combination of HLA class I and KIR. Characterizing Maori and Polynesians is a paucity of HLA-B allotypes recognized by KIR. Compensating for this deficiency are high frequencies (>50 %) of HLA-A allotypes recognized by KIR. These HLA-A allotypes are ones that modern humans likely acquired from archaic humans at a much earlier time.

Unambiguous high resolution genotyping of human leukocyte antigens.

We have developed a high resolution sequencing based typing method for genotyping Human Leukocyte Antigens (HLA) over a period of twenty years. The methods are based upon the separation of HLA alleles per locus at the initial amplification to simplify the analysis post-sequencing. The increasing discovery of polymorphism in HLA, manifested in new alleles, has necessitated the continuing development of this method. Here we present methods for the high resolution Sequence Based Typing of HLA-A, B, C (class I) and HLA-DQB1 and DRB1 (class II). The purpose of this article is to provide a valuable resource of methods and primers for other laboratories engaged in HLA typing.

Diversity in exon 5 of HLA-C(∗)04:01:01G is significant in anthropological studies.

Polymorphisms in Human Leukocyte Antigen (HLA) class I genes are generally considered to be relevant only if they reside in exons 2 and 3 or if they affect the expression of the allele. HLA-C(∗)04:82 differs from the common HLA-C(∗)04:01:01 by having a 9 nucleotide, or 3 amino acid duplication, in exon 5. Having observed HLA-C(∗)04:82 in a New Zealand Maori stem cell patient, we have attempted to examine the prevalence of this allele in different ethnicities. Although our studies are in a limited number of patients and donors, they have revealed that, in the Pacific region, HLA-C(∗)04:82 appears to be the most common allele of the HLA-C(∗)04:01:01G group of alleles, notably in Filippinos and in Maori/Polynesians. In these populations this allele has characteristic HLA-ABCDRB1 haplotypes. Thus, our studies have shown that polymorphisms outside of the clinically important exons can be considered to be relevant in anthropological studies.

Novel Approaches and Technologies in Molecular HLA Typing.

The invention of the Polymerase Chain Reaction (PCR) has revolutionized molecular biology enabling gene isolation and characterization in hours rather than days. Scientists working in transplant diagnostics have proven to be pioneers in adapting this molecular technique to the clinical needs of histocompatibility testing. This chapter describes a number of novel genotyping technologies which have been used to address the challenges posed by genetic diversity seen in the extensive polymorphism in HLA genes. These novel approaches include single-stranded and duplex conformational analyses, real-time PCR, microarray hybridization, RNA-based sequencing, and the present day Next Generation Sequencing. The chapter concludes with a brief look at a possible next, Next Generation Sequencing system.

Recent Developments in Transplantation and Transfusion Medicine.

Transplantation and transfusion are related and clinically important areas of multidisciplinary expertise, including pre-operative treatment, donor recruitment, tissue matching, and post-operative care. We have seen significant developments in these areas, especially in the late 20th and early 21st century. This paper reviews the latest advances in modern transplantation and transfusion medicine, including several new genetic markers (e.g., major histocompatibility complex class I chain-related gene A, killer cell immunoglobulin-like receptor, and human platelet antigens) for donor and recipient matching, genotyping platforms (e.g., next-generation sequencer and Luminex technology), donor recruitment strategies, and several clinical applications in which genotyping has advantages over agglutination tests (e.g., genotyping of weakly expressed antigens and determination of blood groups and human leukocyte antigen types in multi-transfused patients). We also highlight the roles of population studies and international collaborations in moving towards more efficient donor recruitment strategies.

A "silent" nucleotide substitution in exon 4 is responsible for the "alternative expression" of HLA-A*01:01:38L through aberrant splicing.

A Welsh Bone Marrow Donor Registry donor was serologically typed, using both alloantisera and monoclonal antibodies, as human leukocyte antigen (HLA)-A2, A-, but typed by polymerase chain reaction sequence-specific priming as HLA-A*01, A*02. Full gene sequencing of the A*01 separated allele indicated an apparently normal A*01:01:01:01 apart from a silent change at nucleotide 705 in exon 4, codon 211 (alanine: normally GCG but GCA in this donor). Sequence analysis of the amplified A*01 allele in cDNA synthesized from RNA indicated that exons 1, 2, 3, and 5 had typical A*01:01 sequences. However, exon 4 was truncated in this allele (87 nucleotides shorter), beginning just after the single nucleotide polymorphism (SNP) identified in genomic DNA sequencing. The nucleotide sequence up to, and 1 nucleotide after, the SNP is homologous with the 3' end of human leukocyte antigen (HLA)-A intron 3 and thus resembles a splice site. However, a small amount of "normal" HLA-A1 was detected on the surface of cells from an Epstein-Barr virus transformed B-cell line (BCL), but not on peripheral blood mononuclear cells, by flow cytometry. Additionally, a trace amount of "normal sized" A*01 was amplified from cDNA. We suggest that in this A*01 variant allele (A*01:01:38L) intron 3 is largely spliced out with a part of exon 4; exon 4 is still in-frame but the protein is smaller than the wild type. This is likely to affect folding and assembly of the "wild type" mature protein on the cell surface, thus explaining the apparent null phenotype when assayed by conventional serology. However, a small amount of A1 protein is made from correctly spliced A*01 mRNA and is detectable on BCLs using flow cytometry.

Advanced technology for storage and transport of purified DNA from umbilical cord blood prior to use in human leukocyte antigens typing and whole-genome microarray analysis.

Two technologies for dry-state, ambient temperature transport of biospecimens were evaluated in this study. Umbilical cord blood (UCB) samples from 4 individuals were transported at ambient temperature using GenPlates, and the DNA recovered was compared with DNA purified directly from granulocytes of the same UCB samples. GenTegra™ DNA tubes were then used to transport the DNA from California to North Carolina and New Zealand, either immediately after drying or following 30 days of storage at 25°C and 76°C. The integrity of the recovered DNA was thoroughly tested using 2 human leukocyte antigens (HLA)-typing techniques (bead array and sequencing), as well as microarray-based whole-genome scanning. HLA-typing results were the same for all samples whether the DNA had been stored for 3 days during transport or 30 days at either 25°C or 76°C. There were no differences in the HLA-typing results of DNA recovered from UCB samples stored in GenPlates compared with DNA extracted directly from granulocytes. Moreover, the microarray analysis revealed call rates of >99.5% for every sample, regardless of storage method, with a statistical concordance of 99.99% between the UCB samples stored in GenPlates compared with DNA extracted directly from granulocytes. These results indicate that both GenPlates and GenTegra are viable methods of storing and transporting UCB (stem cell) biospecimens in a dry state. The quality and quantity of DNA recovered using both technologies are sufficient for complex genotyping using a number of different methods.