Search

With the advent of cellular therapies, it has become clear that the success of future therapies in prolonging allograft survival will require an intimate understanding of the allorecognition pathways and effector mechanisms that are responsible for chronic rejection and late graft loss.Here, we consider current understanding of T-cell allorecognition pathways and discuss the most likely mechanisms by which these pathways collaborate with other effector mechanisms to cause allograft rejection. We also consider how this knowledge may inform development of future strategies to prevent allograft rejection.Although both direct and indirect pathway CD4 T cells appear active immediately after transplantation, it has emerged that indirect pathway CD4 T cells are likely to be the dominant alloreactive T-cell population late after transplantation. Their ability to provide help for generating long-lived alloantibody is likely one of the main mechanisms responsible for the progression of allograft vasculopathy and chronic rejection.Recent work has suggested that regulatory T cells may be an effective cellular therapy in transplantation. Given the above, adoptive therapy with CD4 regulatory T cells with indirect allospecificity is a rational first choice in attempting to attenuate the development and progression of chronic rejection; those with additional properties that enable inhibition of germinal center alloantibody responses hold particular appeal.

Recent advances in stem cell science and regenerative medicine continue to promote enthusiasm for their potential to treat a range of human diseases. Therapeutic human tissues may, in principle, be generated from either embryonic stem cells (hESC), which have the potential to differentiate into any somatic tissue and are capable of extensive self-renewal, or from induced pluripotent stem cells (hiPSC) generated from adult cells such as fibroblasts, which have similar properties to ESC but are not dependent upon a source of embryos. The likelihood that stem cell transplantation will generate an immune response resulting in rejection of the transplanted tissue remains unclear and depends, in part, upon the potential for tissues derived from unrelated stem cell donors to express foreign human leukocyte antigens (HLA). This chapter draws on experience of clinical solid organ and cell transplantation to identify the factors that initiate an immune response to transplantation, and considers the evidence from stem cell research that tissues generated from stem cells may, at some point in their development, become susceptible to immunological rejection. Options for avoiding the rejection response are explored.

Background Our preliminary work has indicated that donor HLA immunogenicity in kidney and haemopoietic stem-cell transplantation might be predicted by assessment of their aminoacid sequence and physicochemical properties. We have now created a novel computational algorithm to quantify structural and surface electrostatic potential differences between donor and recipient HLA and applied it to predict alloantibody responses in a unique patient cohort. Methods We examined 141 patients undergoing treatment for infertility with lymphocyte immunotherapy. Patients were injected subcutaneously with partners' lymphocytes, and serum samples were collected before and after immunotherapy to assess sensitisation. After four-digit HLA typing and HLA structural modelling, donor–recipient HLA comparisons were performed to determine electrostatic mismatch score (EMS-3D) and assess its ability to predict development of donor-specific alloantibody and overall sensitisation to HLA after immunotherapy. Overall sensitisation was expressed as calculated reaction frequency (cRF), a measure that denotes incompatibility with a UK pool of 10 000 organ donors. Findings Donor EMS-3D was a strong predictor of overall HLA class I and class II sensitisation risk (cRF >15%) (odds ratio [OR] 5·68 per unit increase, 95% CI 1·84–17·49; p=0·002) with a receiver operating characteristic area under curve score of 0·68 for cRF of more than 15% (p=0·0046) and 0·71 for cRF more than 85% (p Interpretation Our study provides compelling evidence that donor HLA immunogenicity can be predicted by assessment of their structural and physicochemical disparities to recipient HLA. If confirmed in larger studies, our findings might enable better assessment of transplant immunological risk before transplantation and could inform future policies on allocation of deceased-donor kidney and haemopoietic stem-cell transplants to maximise the benefits of transplantation. Funding Royal College of Surgeons of England Research Fellowship, Kiel University Starter Grant, Evelyn Trust, Academy of Medical Sciences.

Use of kidneys donated after controlled circulatory death has increased the number of transplants undertaken in the UK but there remains reluctance to use kidneys from older circulatory-death donors and concern that kidneys from circulatory-death donors are particularly susceptible to cold ischaemic injury. We aimed to compare the effect of donor age and cold ischaemic time on transplant outcome in kidneys donated after circulatory death versus brain death.We used the UK transplant registry to select a cohort of first-time recipients (aged ≥ 18 years) of deceased-donor kidneys for transplantations done between Jan 1, 2005, and Nov 1, 2010. We did univariate comparisons of transplants from brain-death donors versus circulatory-death donors with χ tests for categorical data and Wilcoxon tests for non-parametric continuous data. We used Kaplan-Meier curves to show graft survival. We used Cox proportional hazards regression to adjust for donor and recipient factors associated with graft-survival with tests for interaction effects to establish the relative effect of donor age and cold ischaemia on kidneys from circulatory-death and brain-death donors.6490 deceased-donor kidney transplants were done at 23 centres. 3 year graft survival showed no difference between circulatory-death (n=1768) and brain-death (n=4127) groups (HR 1·14, 95% CI 0·95-1·36, p=0·16). Donor age older than 60 years (compared with40 years) was associated with an increased risk of graft loss for all deceased-donor kidneys (2·35, 1·85-3·00, p0·0001) but there was no increased risk of graft loss for circulatory-death donors older than 60 years compared with brain-death donors in the same age group (p=0·30). Prolonged cold ischaemic time (24 h vs12 h) was not associated with decreased graft survival for all deceased-donor kidneys but was associated with poorer graft survival for kidneys from circulatory-death donors than for those from brain-death donors (2·36, 1·39-4·02, p for interaction=0·004).Kidneys from older circulatory-death donors have equivalent graft survival to kidneys from brain-death donors in the same age group, and are acceptable for transplantation. However, circulatory-death donor kidneys tolerate cold storage less well than do brain-death donor kidneys and this finding should be considered when developing organ allocation policy.UK National Health Service Blood and Transplant; Cambridge National Institute for Health Research Biomedical Research Centre.

Essential help for long-lived alloantibody responses is theoretically provided only by CD4 T cells that recognize target alloantigen, processed and presented by the allospecific B cell. We demonstrate that in an alloresponse to multiple MHC disparities, cognate help for class-switched alloantibody may also be provided by CD4 T cells specific for a second “helper” alloantigen. This response was much shorter-lived than when help was provided conventionally, by Th cell recognition of target alloantigen. Nevertheless, long-lasting humoral alloimmunity developed when T cell memory against the helper alloantigen was first generated. Costimulatory blockade abrogated alloantibody produced through naive Th cell recognition of target alloantigen but, crucially, blockade was ineffective when help was provided by memory responses to the accessory helper alloantigen. These results suggest that memory Th cell responses against previously encountered graft alloantigen may be the dominant mechanism for providing help to generate new specificities of alloantibody in transplant patients receiving immunosuppression.

The use of embryonic, induced pluripotent, or adult stem cells is upheld as a potentially valuable therapeutic approach for replacement or repair of diseased and damaged tissues, partly because these immature cells are considered to be non-immunogenic. It is becoming increasingly clear, however, that tissues differentiated from such stem cell sources have the potential to express immunogenic molecules and will be susceptible to a patient’s immune response. This chapter draws on experience of organ and tissue transplantation and the study of transplant immunology to identify cellular and molecular mechanisms that are likely to be relevant to the rejection of stem cell-derived tissues. Pathways of cellular recognition and immune activation are described, together with effector mechanisms that may be responsible, not only for destruction of stem cell transplants, but also for regulating immune responses, thereby improving their chance of survival.

Understanding the influence of co-dopants in the luminescence enhancement of carbonate glasses is the key issue in dosimetry. A series of borate glasses modified by lithium and potassium carbonate were synthesized by the melt-quenching method. The glass mixture activated with various concentrations of TiO2 and MgO was subjected to various doses of gamma-rays ((60)Co). The amorphous nature of the samples was confirmed by x-ray diffraction (XRD) spectra. The simple glowing curve of the glass doped with TiO2 features a peak at 230°C, whose intensity is maximal at 0.5 mol% of the dopant. The intensity of the glowing curve increases with the concentration of MgO added as a co-dopant up to 0.25 mol%, where it is two times higher than for the material without MgO thermoluminescence properties, including dose response, reproducibility, and fading were studied. The effective atomic number of the material was also determined. Kinetic parameters, such as kinetics order, activation energy, and frequency factor are estimated. The photoluminescence spectra of the titanium-doped glass consist of a prominent peaks at 480 nm when laser excitation at 650 nm is used. A three-fold photoluminescence enhancement and a blue shift of the peak were observed when 0.1% MgO was introduced. In addition, various physical parameters, such as ion concentration, polaron radius and internuclear distances were calculated. The mechanism for the thermoluminescence and photoluminescence enhancements are discussed.

The third edition of the joint British Transplantation Society/Renal Association guidelines for living donor kidney transplantation was published in May 2011. The guideline has been extensively revised since the previous edition in 2005 and has used the GRADE system to rate the strength of evidence and recommendations. This article summarizes the statements of recommendation contained in the guideline, which provide a framework for the delivery of living kidney donation in the United Kingdom and may be of wide international interest. It is recommended that the full guideline document is consulted for details of the relevant references and evidence base. This may be accessed at http://www.bts.org.uk/transplantation/standards-and-guidelines/ and http://www.renal.org/clinical/OtherGuidelines.aspx (transplantation is welcome to add a web link in this article to/through its own Web site to increase traffic).

Chronic allograft vasculopathy (CAV) is a major cause of organ transplant failure that responds poorly to treatment. Endothelial activation, dysfunction and apoptosis contribute to CAV, whereas strategies for protecting endothelium and maximizing endothelial repair may diminish it. Late outgrowth endothelial progenitor cells (LO-EPC) can home to areas of injury and integrate into damaged vessels, implying a role in vascular repair; however, in an allograft, LO-EPC would be exposed to the hazardous microenvironment associated with transplant-related ischaemia reperfusion (I/R) injury and persistent inflammation. We evaluated the in vitro effect of I/R injury and the proinflammatory cytokine tumour necrosis factor (TNF)-α on LO-EPC phenotype and function. We show that LO-EPC are intrinsically more tolerant than mature EC to I/R injury induced apoptosis, maintaining their proliferative, migratory and network formation capacity. Under inflammatory conditions, LO-EPC were activated and released higher levels of inflammatory cytokines, upregulated adhesion molecule expression, and were more susceptible to apoptosis. Lentiviral vector-mediated overexpression of the protective gene A20 in LO-EPC maintained their angiogenic phenotype and function, and protected them against TNF-α-mediated apoptosis, reducing ICAM-1 expression and inflammatory cytokine secretion. Administration of ex vivo modified LO-EPC overexpressing A20 might effect vascular repair of damaged allografts and protect from CAV.

Tertiary lymphoid organs (TLOs) may develop within allografts, but their contribution to graft rejection remains unclear. Here, we study a mouse model of autoantibody-mediated cardiac allograft vasculopathy to clarify the alloimmune responses mediated by intragraft TLOs and whether blocking lymphotoxin-β-receptor (LTβR) signaling, a pathway essential for lymphoid organogenesis, abrogates TLO development. TLOs (defined as discrete lymphoid aggregates associated with high endothelial venules) were detectable in 9 of 13 heart allografts studied and were predominantly B cell in composition, harboring germinal-center activity. These are most likely manifestations of the humoral autoimmunity triggered in this model after transplantation; TLOs did not develop if autoantibody production was prevented. Treatment with inhibitory LTβR-Ig fusion protein virtually abolished allograft TLO formation (mean TLOs/heart: 0.2 vs. 2.2 in control recipients; P=0.02), with marked attenuation of the autoantibody response. Recipients primed for autoantibody before transplantation rejected grafts rapidly, but this accelerated rejection was prevented by postoperative administration of LTβR-Ig (median survival time: 18 vs. >50 d, respectively, P=0.003). Our results provide the first demonstration that TLOs develop within chronically rejecting heart allografts, are predominantly B cell in origin, and can be targeted pharmacologically to inhibit effector humoral responses.

Recent advances in stem cell technology have generated enthusiasm for their potential to study and treat a diverse range of human disease. Pluripotent human stem cells for therapeutic use may, in principle, be obtained from two sources: embryonic stem cells (hESCs), which are capable of extensive self-renewal and expansion and have the potential to differentiate into any somatic tissue, and induced pluripotent stem cells (iPSCs), which are derived from differentiated tissue such as adult skin fibroblasts and appear to have the same properties and potential, but their generation is not dependent upon a source of embryos. The likelihood that clinical transplantation of hESC- or iPSC-derived tissues from an unrelated (allogeneic) donor that express foreign human leucocyte antigens (HLA) may undergo immunological rejection requires the formulation of strategies to attenuate the host immune response to transplanted tissue. In clinical practice, individualized iPSC tissue derived from the intended recipient offers the possibility of personalized stem cell therapy in which graft rejection would not occur, but the logistics of achieving this on a large scale are problematic owing to relatively inefficient reprogramming techniques and high costs. The creation of stem cell banks comprising HLA-typed hESCs and iPSCs is a strategy that is proposed to overcome the immunological barrier by providing HLA-matched (histocompatible) tissue for the target population. Estimates have shown that a stem cell bank containing around 10 highly selected cell lines with conserved homozygous HLA haplotypes would provide matched tissue for the majority of the UK population. These simulations have practical, financial, political and ethical implications for the establishment and design of stem cell banks incorporating cell lines with HLA types that are compatible with different ethnic populations throughout the world.

Background. There has been a marked recent increase in the proportion of kidneys transplanted from live donors (LD) and donors after cardiac death (DCD) compared with donors after brain death (DBD). The purpose of this study was to compare the incidence of major urologic complications (MUCs: urinary leak and ureteric stenosis [US]) in kidney transplants procured from LD, DCD, and DBD and to identify the factors associated with MUCs. Methods. We studied 901 consecutive renal transplants (LD: 181, DCD: 198, and DBD: 522) performed in the Cambridge Transplant Centre during 1998 to 2008 by retrieving data from a prospective, cross-audited database, and detailed case note review. An ureteroneocystostomy over a double pigtail ureteric stent was performed in all transplants, and ureteric stents were removed after approximately 6 weeks. All ureteric stenoses were treated by surgical reconstruction. Results. Three patients developed urine leak, and 21 developed US. There was no significant difference in the incidence of US in kidneys retrieved from LD (2.8%), DBD (1.7%), or DCD (3.5%; P=0.28). Recipients with US had a higher incidence of acute rejection (48% vs. 27%; hazard ratio 3.2, P=0.005) and urinary tract infections before the diagnosis of US (48% vs. 19%; hazard ratio 3.0, P=0.01). The incidence of delayed graft function (38% vs. 26%), cold ischemia times (12.9 vs. 13.5 hr), and graft survival was not significantly associated with US. Conclusions. The incidence of MUCs is similar in kidneys transplanted from LD, DCD, and DBD. When complications do occur, they can be treated successfully by surgical reconstruction.

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology (BCSH) and the British Transplantation Society (BTS) has reviewed the available literature and made recommendations for the diagnosis and management of post-transplant lymphoproliferative disorder (PTLD) in adult recipients of solid organ transplants. This review details the risk factors predisposing to development, initial features and diagnosis. It is important that the risk of developing PTLD is considered when using post transplant immunosuppression and that the appropriate investigations are carried out when there are suspicions of the diagnosis. These must include tissue for histology and computed tomography scan to assess the extent of disease. These recommendations have been made primarily for adult patients, there have been some comments made with regard to paediatric practice.

The dry period is now recognised as a critical time for the control of clinical and sub-clinical mastitis in dairy cattle. Infections that occur, or that are not cured, during the dry period often result in clinical mastitis or raised somatic cell counts in early lactation. There is known to be large variability between herds in the patterns of dry period intramammary infections (IMI) and yet, until recently, there has been no information on farm determinants of the risk of IMI, other than in relation to dry cow treatments. In this paper we consider new research on cow characteristics, farm facilities and herd management strategies during the dry period in relation to clinical mastitis and raised somatic cell counts (SCC) in early lactation. We then describe, within a Bayesian framework, the concept of synthesising existing knowledge with new data to facilitate decision-making on dry cow management for individual farms.

We have shown previously that human leukocyte antigen (HLA) immunogenicity, defined by the physiochemical properties of mismatched amino acids, predicts humoral alloimmunity, and now report the effect on long-term graft survival after kidney transplantation. The influence of HLA-A and -B mismatch, number of amino acid mismatches (after interlocus subtraction) and their physiochemical (electrostatic and hydrophobic) disparity on the outcome of fully HLA matched and single HLA-A or -B mismatched deceased donor kidney transplants undertaken in the United Kingdom (1990–2005) were analyzed ( n = 5,247). Grafts with a single HLA-A or -B mismatch had significantly lower survival than fully matched transplants (81.9% vs 84.2% at 5 years, p = 0.004). However, single HLA-A or -B mismatched grafts with no or one amino acid mismatch had better survival than grafts with two or more amino acid mismatches (89.3% vs 81.8% at 5 years, HR 1.5, p = 0.03). The number of mismatched amino acids was an independent predictor of transplant survival after adjusting for the underlying HLA matching effect ( p = 0.02). Physiochemical disparity scores correlated closely with amino acid mismatches and provided no additional predictive value. The immunogenicity of HLA class I alloantigens defined at the level of amino acid sequence correlates more closely with outcome after renal transplantation than conventional serologic HLA matching.

The outcome after living donor renal transplantation is superior to that for deceased donor transplantation, but the results are not uniformly successful. The factors responsible for the variable outcome after living donor transplantation have not been well defined.UK Transplant Registry data were analyzed to determine the outcomes of 3142 first adult kidney transplants from living donors (71% genetically related and 29% unrelated) performed between 2000 and 2007 inclusive. Kaplan-Meier survival estimates were determined, and factors that might be associated with graft and patient survival were analyzed using Cox proportional hazards regression modeling.Patient survival at 5 years was better for recipients of grafts from related than unrelated donors (97% vs. 93%, P=0.0002), but conversely graft survival was better in recipients of genetically unrelated grafts (93% vs. 89%, P=0.06). After adjustment for the factors found to influence graft and patient survival, these differences were no longer apparent. In contrast to the expectations, the degree of human leukocyte antigen-A, -B, and -DR mismatch did not influence graft survival. Increasing donor age (but not recipient age), recipient diabetes, and grafts from adult offspring were independently associated with poorer patient survival in the first 3 years after transplantation. Poorer graft survival was independently associated with donor age older than 59 years, and female recipients.Advanced donor age, but not human leukocyte antigen mismatch, is associated with poorer outcome after live donor kidney transplantation. However, the results of live donor transplantation remain superior to deceased donor kidney transplantation.

Background. Outcomes after deceased heart beating donor kidney transplantation are good, but survival rates vary according to a number of donor-, recipient-, and transplant-related factors. This comprehensive analysis of transplant outcomes was undertaken to inform development of a new Kidney Allocation Scheme. Methods. A complete case analysis of the outcome of kidney-only transplants in the United Kingdom, 1995 to 2001, was undertaken using Cox regression modeling. Seven thousand three hundred eighty-five (77%) of the 9585 transplants reported to the UK Transplant Registry were primary transplants in adults. Regrafts and pediatric patients (age

This paper examines both the processes and outcomes of governance in the context of the EU’s relationship with ACP States within the period of the Cotonou Agreement (CA). It discusses and assesses a variety of governance mechanisms, including the European Commission’s use of the governance concept, EPAs, manifestations of partner preferences, the EDF, the revision of the CA, and Fisheries Partnership Agreements. Specific examples of the wielding of each mechanism are assessed based upon two criteria: a) the extent to which the wielding of the mechanism by the EU is a manifestation of “good governance," and b) the extent to which the EU’s wielding of the mechanism has resulted, or is likely to result, in the sustainable development of and reduction of poverty in ACP countries. The examples are chosen to illustrate contradictions between rhetoric and practice and the consequential negative (actual and potential) impact upon development in ACP States. The final section offers suggestions for improving the EU’s governance processes and their outcomes for development.

The Mercury Imaging X-ray Spectrometer (MIXS) on the BepiColombo Mercury Planetary Orbiter (MPO), will measure fluorescent X-ray emission from the surface of Mercury in the energy range 0.5 – 7.5 keV, which is induced by incident solar X-rays and solar wind electrons and protons. These X-rays will reveal the elemental composition of the surface of Mercury and aid the determination of the planet's evolution.\ud \ud MIXS is a two component instrument. A collimated channel (MIXS-C) provides measurements on scales of 70-270 km, sufficient to separate the major Mercurian terrains. A second channel (MIXS-T) is the first imaging X-ray telescope for planetary remote sensing and will make measurements on spatial scales of less than 10 km for major elements during solar flares, sufficient to isolate surface landforms, such as craters and their internal structures. The spatial resolution achieved by MIXS-T is made possible by novel, low mass microchannel plate X-ray optics, in a Wolter type I optical geometry.\ud \ud MIXS measurements of surface elemental composition will help determine rock types, the evolution of the surface and ultimately a probable formation process for the planet. In this paper we present MIXS and its predicted performance at Mercury as well as discussing the role that MIXS measurements will play in answering the major questions about Mercury.

PVG-rnu/rnu nude rats reject fully allogenic renal (DA) and skin (BN, AO) allografts after the adoptive transfer of naive CD4+ T cells alone, but rejection is accompanied by the accumulation of many nude-derived CD8+ leukocytes within the graft. In addition, mononuclear cells infiltrating the rejecting renal grafts in these animals display cytotoxic activity in vitro against specific and third-party alloantigens. In this investigation we have treated CD4+ T cell-restored nude rats bearing renal or skin allografts with the mAb MRC OX8 to deplete the host of CD8+ cells. In vivo treatment with OX8 completely eliminated CD8+ cells from rejecting grafts of both kidney and skin, but it did not prevent graft rejection, nor did OX8 treatment abolish the cytotoxic effector cells found in nude rat spleen or in graft-infiltrating cells (GIC) of rejecting renal allografts. The nature of the cytotoxic activity was examined with anti-CD3 mAb 1F4, which was shown to block conventional CD8+ Tc killing in vitro but did not inhibit allogeneic target cell lysis by spleen cells from nude rats. The cytotoxic activity found in GIC of rejecting allografts was not inhibited by anti-CD3 mAb, suggesting that these cytotoxic effector cells were CD3-CD8- and were of extrathymic origin. We conclude that non-thymus-derived CD8+ GIC are not essential for allograft rejection in CD4+ T cell-restored nude rats.

The traditional view of graft rejection is one of direct recognition of allogeneic MHC molecules by effector T cells, the phenotype of which may be predicted by the nature of the MHC disparity. In this article, Andrew Bradley and colleagues discuss recent evidence that suggests this view may be an oversimplification, and argue that additional effector mechanisms, such as alloantibody, need to be reconsidered.

Mandatory continuous monitoring of early transplant outcome with centralized oversight was introduced in 2004 for all 23 UK adult kidney transplant units. Risk-adjusted cumulative sum charts are used to assess 30-day graft and patient survival against past performance for each center, and change in transplant center performance is assessed by tabular cumulative sum charts. The monitoring scheme has performed as predicted from simulations used to establish outcome thresholds and has been validated by comparison with 1- and 5-year outcome data for all UK transplant centers. The value and limitations of the scheme are discussed along with changes that may improve its utility as a tool for self-assessment and central oversight.

Background—The development of autoantibody after heart transplantation is increasingly associated with poor graft outcome, but what triggers its development and whether it has a direct causative role in graft rejection is not clear. Here, we study the development of antinuclear autoantibody in an established mouse model of heart allograft vasculopathy.Methods and Results—Humoral vascular changes, including endothelial complement staining, were present in bm12 heart grafts, explanted 50 days after transplantation. Alloantibody was not detectable, but long-lasting autoantibody responses developed in C57BL/6 recipients from the third week after transplantation. No autoantibody was generated if donor CD4 T cells were depleted before heart graft retrieval or in recipients that lacked B-cell major histocompatibility complex class II expression, indicating that humoral autoimmunity is a consequence of donor CD4 T-cell allorecognition of the major histocompatibility complex class II complex on recipient autoreactive B cells. An effector role for autoantibody in graft rejection was confirmed by abrogation of humoral vascular rejection, and attenuation of vasculopathy, in B-cell deficient recipients and by development of vascular obliteration and accelerated rejection in recipients primed for autoantibody before transplantation.Conclusions—Passenger CD4 T cells within heart transplants can contribute to allograft vasculopathy by providing help to recipient B cells for autoantibody generation.

Solid-phase binding assays using purified human leukocyte antigen (HLA) allow the accurate identification and characterization of HLA-specific antibodies in organ transplant patients, but sera may contain factors that block the detection of clinically relevant alloantibodies. The effect of treating patient sera with dithiothreitol (DTT) on alloantibody detection was examined. In 49 sera submitted for routine HLA-specific antibody monitoring, DTT made little difference to immunoglobulin G HLA-specific antibody detection using LABScreen HLA class I and class II mixed beads. However, in sera submitted for antibody identification using single antigen beads (SAB), DTT markedly increased (>twofold increased median fluorescence intensity) antibody binding to HLA class I and/or class II specificities in 14 of 76 (18%) patient sera. In a cohort of highly sensitized patients, treatment of sera with DTT enhanced antibody-binding levels in 14 of 15 (93%) sera. This study highlights the need to consider routine testing of sera with and without DTT for analysis of HLA-specific antibodies by SAB.

Background Ischemia/reperfusion (I/R) injury causes endothelial cell (EC) dysfunction and can precipitate apoptosis. Complex I of the mitochondrial respiratory chain is a target for I/R injury. The β2.7 RNA transcript encoded by human cytomegalovirus (CMV) has been shown to stabilize Complex I by direct physical interaction. In this study, we investigated whether stabilizing Complex I in EC in an in vitro model of ischemia could prevent apoptosis. Methods Lentiviral vectors expressing a full-length β2.7 RNA were generated from a human immunodeficiency virus-1 (HIV-1) construct, in which the viral promoter had been inactivated and virtually all the viral accessory proteins deleted in order to maximize safety. β2.7 gene expression in transduced endothelial cells was examined by reverse transcript–polymerase chain reaction (RT-PCR). EC were prepared from rat aorta. An in vitro hypoxia/reperfusion (H/R) and I/R injury models were set up and apoptosis was assessed using caspase-3 activity. Reactive oxygen species (ROS) production in the endothelial cells was assessed by the capacity to oxidize non-fluorescent dihydrorhodamine-123 (DHR-123) to fluorescent rhodamine-123 and measured by flow cytometry. Results H/R and I/R injury induced formation of ROS and EC apoptosis. Overexpression of the viral β2.7 RNA, which stabilizes Complex I, reduced ROS production and inhibited EC apoptosis. Conclusions β2.7 RNA is a novel effector molecule that can protect rat aortic endothelial cells from I/R injury causing apoptosis. As a non-coding RNA, β2.7 RNA will not induce an immune response in the recipient. We have shown that overexpression of β2.7 RNA can protect RAEC from H/R- or I/R-mediated apoptosis by reduction of ROS formation.

Background. Cytomegalovirus (CMV) is one of the major infections encountered posttransplantation. UK Guidelines (2003) recommend CMV prophylaxis or screening with preemptive treatment for all high risk recipients. Studies predating the widespread use of CMV prophylaxis have shown that CMV seronegative recipients (R−) receiving a renal allograft from a CMV seropositive donor (D+) have worse outcomes than those avoiding primary CMV infection. Therefore, it has been suggested that CMV matching should be a part of the UK national deceased donor kidney allocation scheme. Methods. We examined patient and allograft survival according to donor and recipient CMV serostatus in 10,190 UK adult and pediatric deceased donor renal transplant recipients transplanted between 2000 and 2007. We also ascertained CMV prophylaxis strategies in all UK renal transplant units. Results. Twenty-one of the 22 UK renal transplant centers used prophylactic oral valganciclovir for 3 months posttransplant in the D+R− transplants, having done so for a median of 4 years. Unadjusted data showed that D+R+ rather than D+R− transplants had the lowest patient and allograft survivals at 3 years posttransplant. However, after adjustment for donor age, there was no significant effect of donor and recipient CMV serostatus on allograft or patient survival. Conclusions. These findings suggest that in an era where CMV prophylaxis is used routinely in D+R− transplants, the previously noted adverse effects of primary CMV infection on allograft and patient survival can be avoided (perhaps through a reduction in the incidence and/or severity of primary CMV infection), without using a CMV-matching allocation scheme.

To assist the representation of phenology in vegetation models we created several templates of phenology-driver relations by characterizing the annual phase differences between phenology and two phenology drivers. We did this using the results of a cross spectral analysis of MODIS EVI with radiation (CPTEC) and with precipitation (TRMM). Four phase ranges were identified for phenology-radiation and three phase ranges for phenology-precipitation. These ranges were classified and mapped together into 12 zones of our study area where particular phase relationships coincided. Around ~25% area was in phase with radiation, with varying phase ranges of precipitation, and ~ 16 % was in phase with precipitation with varying phase ranges of radiation. For each zone we conceptualized the phenology-driver relationships with phase lagged curves. The phase timing of these plots matched well with average time series plots from the same zones, but more work is needed on the representation of amplitude.

Liver transplantation provides a return to a satisfactory quality of life (QOL) for the majority of patients in the short to medium term (first 5 years), but there is very little information on the QOL in the longer term and the factors influencing it. We therefore undertook a single-center cross-sectional analysis to determine QOL in patients 10 or more years after liver transplantation. All liver transplant recipients who were followed up at the Cambridge Transplant Unit for 10 or more years (transplanted between 1968 and 1994) and resident in the United Kingdom were asked to complete by post the Short Form 36 version 2 and the Ferrans and Powers questionnaires to evaluate their QOL. Univariate and multivariate analysis were performed to assess the relationship between a range of clinical parameters and QOL. One hundred two patients were invited to participate, and 61 (59.8%) responded. Overall, the patients reported a satisfactory QOL. On the Ferrans and Powers questionnaire, the patients had a mean Quality of Life Index score of 24.5. Factors associated with reduced physical functioning were age50 years at transplantation, female gender, and recurrence of the primary liver disease. On the Short Form 36 version 2 questionnaire, recipients had reduced physical functioning but normal mental health parameters in comparison with the normal population. Age60 years at the time of survey, female gender, and posttransplant complications were associated with reduced physical functioning. In conclusion, patients 10 or more years after liver transplantation generally have a good QOL, although physical functioning is reduced. Addressing issues such as recurrent disease and posttransplant problems such as osteoporosis may help to improve long-term QOL.

Background. Human leukocyte antigen (HLA) matching strategies for kidney transplantation assign equal weighting to mismatches at a particular locus and take no account of variation in immunogenicity according to recipient HLA type. We examined the ability of intra- and interlocus analysis of amino-acid polymorphisms at continuous (triplet) and discontinuous positions (eplet) defined by the HLAMatchmaker program to predict alloantigen immunogenicity. Methods. Sera from highly sensitized patients were screened for HLA class-I alloantibodies and mismatched combinations were analyzed using HLAMatchmaker to determine the number of triplet or extended-triplet and eplet mismatches. Results. Logistic regression analysis revealed a strong correlation between the number of triplet or extended-triplet and eplet mismatches and both the presence and magnitude of alloantibody to mismatched HLA-A and -B specificities. The additional structural information provided by eplet analysis gave increased discrimination of mismatched-HLA specificities for alloantigens with greatest sequence disparity but this did not further improve the ability of triplet analysis to predict alloantigen immunogenicity. High antibody levels were observed for several mismatched-HLA combinations with zero triplet or eplet mismatches indicating that self triplets or eplets expressed in different conformations do not always predict nonimmunogenic epitopes. Conclusion. Analysis of recipient HLA type and mismatched-HLA alloantigens using the HLAMatchmaker algorithm allows prediction of immunogenic donor HLA types.

Donor dendritic cells are potent but short-lived stimulators of early transplant rejection, and recipient antigen presenting cells presenting donor major histocompatibility complex peptides sustain immunoreactivity and contribute to chronic rejection. We briefly consider how CD4 T cells that recognize allopeptide can provide help for effector and regulatory responses and highlight the implications for promoting graft survival.