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Derek Middleton

Publications and source records attributed to Derek Middleton.

At least 19 recordsLinked to original sources
PubMed2007

Functional polymorphism of the KIR3DL1/S1 receptor on human NK cells.

NK cells express both inhibitory and activatory receptors that allow them to recognize target cells through HLA class I Ag expression. KIR3DL1 is a receptor that recognizes the HLA-Bw4 public epitope of HLA-B alleles. We demonstrate that polymorphism within the KIR3DL1 receptor has functional consequences in terms of NK cell recognition of target. Inhibitory alleles of KIR3DL1 differ in their ability to recognize HLA-Bw4 ligand, and a consistent hierarchy of ligand reactivity can be defined. KIR3DS1, which segregates as an allele of KIR3DL1, has a short cytoplasmic tail characteristic of activatory receptors. Because it is very similar to KIR3DL1 in the extracellular domains, it has been assumed that KIR3DS1 will recognize a HLA-Bw4 ligand. In this study, we demonstrate that KIR3DS1 is expressed as a protein at the cell surface of NK cells, where it is recognized by the Z27 Ab. Using this Ab, we found that KIR3DS1 is expressed on a higher percentage of NK cells in KIR3DS1 homozygous compared with heterozygous donors. In contrast to the inhibitory KIR3DL1 allotypes, KIR3DS1 did not recognize HLA-Bw4 on EBV-transformed cell lines.

Alleles↗
PubMed2006

Investigation of KIR gene frequencies in type 1 diabetes mellitus.

The frequency of killer immunoglobulinlike receptors (KIR) genes was examined in type 1 diabetes mellitus patients and controls from Finland. The KIR gene 2DS5 was significantly decreased in patients versus controls, but this was no longer significant after correction for the number of comparisons made.

Adolescent↗
PubMed2006

Human NK cell education by inhibitory receptors for MHC class I.

Natural killer (NK) cells recognize the absence of self MHC class I as a way to discriminate normal cells from cells in distress. In humans, this "missing self" recognition is ensured by inhibitory receptors such as KIR, which dampen NK cell activation upon interaction with their MHC class I ligands. We show here that NK cells lacking inhibitory KIR for self MHC class I molecules are present in human peripheral blood. These cells harbor a mature NK cell phenotype but are hyporesponsive to various stimuli, including MHC class I-deficient target cells. This response is in contrast to NK cells that express a single inhibitory KIR specific for self MHC class I, which are functionally competent when exposed to the same stimuli. These results show the involvement of KIR-MHC class I interactions in the calibration of NK cell effector capacities, suggesting its role in the subsequent "missing self" recognition.

Animals↗
PubMed2006

The repercussions of implementing flow cytometry as a single HLA antibody screening technique in prospective renal transplant recipients.

In an effort to replace the complement-dependent cytotoxicity test (CDC) with a more sensitive single technique we looked at flow cytometry as a possible replacement. The Flow PRA Bead technique (One Lambda) performed well in our laboratory. Although as expected this technique was more sensitive and specific than CDC, there remained 11 samples from eight patients which were flow negative, CDC positive. The results of various antibody identification tests on these samples prompted us to alter the positive selection criteria which we had been using on our routine screening with the Flow PRA Beads and persuaded us that the initial CDC result was correctly positive in nine of the 11 samples.

Complement System Proteins↗
PubMed2005

HLA genes in Madeira Island (Portugal) inferred from sequence-based typing: footprints from different origins.

Human leukocyte antigen (HLA)-A, HLA-B, and HLA-DRB1 polymorphisms were examined in Madeira Island populations. The data was obtained at high-resolution level, using sequence-based typing (SBT). The most frequent alleles at each loci were: A*020101 (24.6%), B*5101 (9.7%), B*440201 (9.2%), and DRB1*070101 (15.7%). The predominant three-loci haplotypes in Madeira were A*020101-B*510101-DRB1*130101 (2.7%) and A*010101-B*0801-DRB1*030101 (2.4%), previously found in north and central Portugal. The present study corroborates historical sources and other genetic studies that say Madeira were populated not only by Europeans, mostly Portuguese, but also sub-Saharan Africans due to slave trade. Comparison with other populations shows that Madeira experienced a stronger African influence due to slave trade than Portugal mainland and even the Azores archipelago. Despite this African genetic input, haplotype and allele frequencies were predominantly from European origin, mostly common to mainland Portugal.

Gene Frequency↗
PubMed2005

Analysis of KIR ligand incompatibility in human renal transplantation.

Natural killer cells express killer immunoglobulin-like receptors (KIR) that bind to MHC class I antigens. Lack of self-MHC on the target cell can cause NK-cell mediated killing. Here, we analyzed the effect of KIR ligand incompatiblity on renal allograft survival in humans. Kidney recipient/donor pairs were separated according to their HLA-Cw alleles and HLA-Bw4 specificity which are considered epitopes for KIR. A total of 2,757 renal transplants were examined. Graft survival rates were computed according to the Kaplan-Meier method. No effect of KIR ligand matching on graft survival was observed in cadaver kidney transplants. Our results indicate that KIR ligand matching cannot be recommended as a strategy for improving renal allograft survival.

Graft Survival↗
PubMed2005

HLA polymorphisms in Cabo Verde and Guiné-Bissau inferred from sequence-based typing.

Human leukocyte antigen (HLA)-A, -B, and -DRB1 polymorphisms were examined in the Cabo Verde and Guiné-Bissau populations. The data were obtained at high-resolution level, using sequence-based typing. The most frequent alleles in each locus was: A*020101 (16.7% in Guiné-Bissau and 13.5% in Cabo Verde), B*350101 (14.4% in Guiné-Bissau and 13.2% in Cabo Verde), DRB1*1304 (19.6% in Guiné-Bissau), and DRB1*1101 (10.1% in Cabo Verde). The predominant three loci haplotype in Guiné-Bissau was A*2301-B*1503-DRB1*1101 (4.6%) and in Cabo Verde was A*3002-B*350101-DRB1*1001 (2.8%), exclusive to northwestern islands (5.6%) and absent in Guiné-Bissau. The present study corroborates historic sources and other genetic studies that say Cabo Verde were populated not only by Africans but also by Europeans. Haplotypes and dendrogram analysis shows a Caucasian genetic influence in today's gene pool of Cabo Verdeans. Haplotypes and allele frequencies present a differential distribution between southeastern and northwestern Cabo Verde islands, which could be the result of different genetic influences, founder effect, or bottlenecks. Dendrograms and principal coordinates analysis show that Guineans are more similar to North Africans than other HLA-studied sub-Saharans, probably from ancient and recent genetic contacts with other peoples, namely East Africans.

Alleles↗
PubMed2005

KIR genes.

This review updates the on-going investigations into KIR genes and their alleles with the main emphasis on what has taken place in this laboratory over the last 3 years.

Alleles↗
PubMed2005

The silent KIR3DP1 gene (CD158c) is transcribed and might encode a secreted receptor in a minority of humans, in whom the KIR3DP1, KIR2DL4 and KIR3DL1/KIR3DS1 genes are duplicated.

Killer-cell Ig-like receptors (KIR) are structurally and functionally diverse, and enable human NK cells to survey the expression of individual HLA class I molecules, often altered in infections and tumors. Multiple events of non-reciprocal recombination have contributed to the rapid diversification of KIR. We show that approximately 4.5% of the individuals of a Caucasoid population bear a recombinant allele of KIR3DP1, officially designed KIR3DP1*004, that associates tightly with gene duplications of KIR3DP1, KIR2DL4 and KIR3DL1/KIR3DS1. The KIR3DP1 gene is normally silent, but the recombinant allele carries a novel promoter sequence and, as a consequence, is transcribed in all tested individuals. Messenger RNA of KIR3DP1*004 is made up of six exons; of these, exons 1-5 are similar to, and spliced like, those encoding the leader peptide and Ig-domains of KIR3D. By contrast, exon 6 is homologous to no other human KIR sequence, but only to possible homologs in chimpanzees and rhesus macaques, and encodes a short hydrophilic tail. The putative KIR3DP1*004 product, like those of the related genes LAIR-2 and LILRA3/ILT6/LIR4, is predicted to be secreted to the extracellular medium rather than anchored to the cell membrane.

Alleles↗
PubMed2005

Activating killer cell immunoglobulin-like receptor gene KIR2DS1 is associated with psoriatic arthritis.

Killer cell immunoglobulin-like receptor genotyping was performed on a cohort of American Caucasian patients with psoriasis to investigate any possible relationship between these chromosome 19 genes and autoimmune-linked disease. This patient cohort also contained a subgroup of patients who had been additionally diagnosed as positive for psoriatic arthritis (PsA). Because of the known association of human leucocyte antigen (HLA)-Cw*06 with psoriasis, the study concentrated on the five KIR genes that have HLA-C as their recognized ligand (i.e., KIR2DL1, -2DL2, -2DL3, -2DS1, and -2DS2). An increase in the frequency of the activating KIR2DS1 gene was detected in the PsA patients, compared with psoriasis patients negative for PsA and an unaffected American Caucasian control group.

Arthritis, Psoriatic↗
PubMed2004

Investigation of KIR diversity in immunosenescence and longevity within the Irish population.

Natural killer (NK) cells play a pivotal role in the innate immune response. During the ageing process, variations occur in NK cell number and function. The cytolytic activity of NK cells is controlled by an array of activating and inhibitory cell surface receptors, including the killer cell immunoglobulin-like receptors (KIRs). In the present study, genetic diversity of the KIR loci was analysed with respect to successful ageing in the Irish population. A PCR-SSOP KIR gene identification system was employed to determine the frequency of the named KIR genes/pseudogenes and KIR genotypes within a healthy aged cohort and young control group. Although, two KIR genes (2DS3, 2DL5) displayed an initial increased frequency in the aged group, the significance of this association was lost when repeated in a second cohort. In view of the lack of studies to date, investigating the role of the KIR gene system in healthy ageing, further analysis of KIR diversity is required to fully elucidate it's role in respect to age-related disease and longevity.

Adult↗
PubMed2004

High resolution HLA-DRB1 identification of a Caucasian population.

Polymerase chain reaction-sequence-specific oligonucleotide probes typing methods have been applied to 1000 individuals from the Northern Ireland population to give human leukocyte antigen DRB1 (HLA-DRB1) allele assignment. HLA-DRB1 allele frequencies and four-locus haplotypes (A/B/C/DR) for this Caucasian population, based on HLA class I and class II allele assignment, are now presented. No significant deviations from Hardy-Weinberg proportions were observed. The HLA-C locus exhibited marginal evidence of selection (p<0.03, uncorrected one-sided test) in the direction of balancing selection; the HLA-A, -B, and -DRB1 allele frequency distributions were compatible with expectations under a neutral model (which does not mean that selection is not operating). Evidence for selection was seen on haplotypes HLA-A*010101-B*0801-DRB1*030101 and HLA-A*290201-B*440301-DRB1*070101 based on their patterns of linkage disequilibrium.

Alleles↗
PubMed2004

Investigation of killer cell immunoglobulinlike receptor gene diversity: I. KIR2DL4.

Polymerase chain reaction-sequence-specific oligonucleotide probes typing procedures identifying alleles of the killer immunoglobulin-like gene (KIR2DL4) have been established. The methods, designed around the specific amplification of the D0 and D2 domains of this gene, produce discrimination of KIR2DL4 alleles. The methods have been applied to a healthy Northern Irish control group, establishing frequencies for this Caucasian population. Additionally, the KIR2DL4 allele status of cell line DNA and CEPH families, from the 13th International Histocompatibility Workshop and local families, have also been investigated.

Alleles↗
PubMed2004

Functional promoter region polymorphism of the proinflammatory chemokine IL-8 gene associates with Parkinson's disease in the Irish.

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders and is characterized by the progressive loss of dopamine neurons in the substantia nigra. There is increasing evidence to suggest the inflammatory response of the brain contributes to the pathogenesis of PD. This study investigated the frequency of polymorphism located in the critical promoter region of the proinflammatory cytokine genes: interleukin (IL)-2, IL-6, IL-8, and tumor necrosis factor alpha (TNF-alpha) within a cohort of patients with PD in comparison to a group of healthy elderly individuals. No association was observed for single nucleotide polymorphism in the promoter regions of the IL-2, IL-6, and TNF-alpha genes. The single nucleotide polymorphism in the chemokine IL-8 gene was observed to associate with PD and appeared to be independent of age at onset. This association further supports the theory that the proinflammatory response in the brains of patients with PD plays a role in the pathogenesis of the disease and warrants further investigation into the role of chemokines in the brain, and a more detailed analysis of the genetics involved in the immune response of the brain.

Aged↗
PubMed2004

Investigation of killer cell immunoglobulin-like receptor gene diversity: II. KIR2DS4.

A polymerase chain reaction sequence-specific oligonucleotide probe typing method identifying and distinguishing alleles of the KIR2DS4 gene has been established. The system is based on the specific amplification of a region of this gene, followed by hybridization with 11 sequence-specific oligonucleotide probes. The method has been applied to a healthy group of Northern Irish caucasian individuals, establishing frequencies of alleles of this locus within the local population. Furthermore, cell line DNA and families from the 13th International Histocompatibility Workshop, in addition to local families, have also been allele typed at the KIR2DS4 locus. Haplotype segregation, with respect to KIR2DS4 alleles, has been examined by using the local family data. Within all sample groups investigated, four KIR2DS4 alleles were identified, two of which are novel to this investigation.

Alleles↗
PubMed2004

Investigation of killer cell immunoglobulin-like receptor gene diversity: IV. KIR3DL1/S1.

The polymorphic nature of the KIR3DL1/S1 gene complex has been investigated through the development of a polymerase chain reaction-sequence-specific oligonucleotide probes (PCR-SSOP) allele typing system. The KIR3DL1/S1 system was applied to a healthy group of Northern Irish individuals to establish allele frequencies within this Caucasian population. Additionally, cell line DNA and CEPH families, both from the 13th International Histocompatibility Workshop, and local families have been investigated. The generated data emphasize the complexity and highly polymorphic nature of this KIR gene complex; 11 allelic variations were identified, 2 of which are novel to this study. Use of the PCR-SSOP system has confirmed the presence of multiple copies of KIR3DL1/S1 alleles in a number of individuals.

Alleles↗
PubMed2004

One thousand renal transplants in Belfast (1968-1998).

The first kidney transplant was performed in Belfast in 1968. During the next 30 years 1,000 transplants were undertaken at this unit. Data were analysed on 937 cadaveric transplants, 815 first and 122 regrafts. There were 63 living transplants. Long-term follow-up was achieved for all grafts except one live transplant. All recipients had follow-up of at least 5 years. One- and 5-year graft survival rates were 78.9% and 65.0% for first cadaveric grafts, 83.6% and 66.4% for regrafts and 85.7% and 68.3% for living transplants. Nine of 41 transplants performed more than 30 years ago are still functioning. Multivariate analysis determined risk factors for graft survival as recipient age, donor age, HLA-A mismatching, HLA cytotoxic antibody level and year of transplant. A conservative regime regarding the use of immunosuppression, HLA matching and crossmatching has proved successful in accomplishing good graft survival at this unit.

Adolescent↗