Renal transplantation outcomes in obese patients: a French cohort-based study.

BACKGROUND: Whilst there are a number of publications comparing the relationship between body mass index (BMI) of kidney transplant recipients and graft/patient survival, no study has assessed this for a French patient cohort. METHODS: In this study, cause-specific Cox models were used to study patient and graft survival and several other time-to-event measures. Logistic regressions were performed to study surgical complications at 30 days post-transplantation as well as delayed graft function. RESULTS: Among the 4691 included patients, 747 patients were considered obese with a BMI level greater than 30 kg/m2. We observed a higher mortality for obese recipients (HR = 1.37, p = 0.0086) and higher risks of serious bacterial infections (HR = 1.24, p = 0.0006) and cardiac complications (HR = 1.45, p < 0.0001). We observed a trend towards death censored graft survival (HR = 1.22, p = 0.0666) and no significant increased risk of early surgical complications. CONCLUSIONS: We showed that obesity increased the risk of death and serious bacterial infections and cardiac complications in obese French kidney transplant recipients. Further epidemiologic studies aiming to compare obese recipients versus obese candidates remaining on dialysis are needed to improve the guidelines for obese patient transplant allocation.

The EKiTE network (epidemiology in kidney transplantation - a European validated database): an initiative epidemiological and translational European collaborative research.

BACKGROUND: Kidney transplantation is considered to be the treatment of choice for people with end-stage renal disease (ESRD). However, due to the shortage of available organs and the increase in the ESRD prevalence in Europe, it is essential to improve transplantation outcomes by studying the related prognostic factors. Today, there is no European registry collecting data to perform such clinical epidemiology studies. MAIN BODY: Entitled EKiTE, for European cohort for Kidney Transplantation Epidemiology, this prospective and multicentric cohort includes patients from Spanish (Barcelona), Belgian (Leuven), Norwegian (Oslo) and French (Paris Necker, Lyon, Nantes, Nancy, Montpellier, Nice and Paris Saint Louis) transplantation centers and currently contains 13,394 adult recipients of kidney (only) transplantation from 2005 and updated annually. A large set of parameters collected from transplantation until graft failure or death with numbers of post-transplantation outcomes. The long-term follow-up and the collected data enable a wide range of possible survival and longitudinal analyses. CONCLUSION: EKiTE is a multicentric cohort aiming to better assess the natural history of the ESRD in European kidney transplant recipients and perform benchmarking of clinical practices. The data are available for clinical epidemiology studies and open for external investigators upon request to the scientific council. Short-term perspectives are to extend EKITE network to other European countries and collect additional parameters in respect of the common thesaurus.

Propensity score-based comparison of the graft failure risk between kidney transplant recipients of standard and expanded criteria donor grafts: Toward increasing the pool of marginal donors.

From a prospective and multicentric French cohort, we proposed an external validation study for the expanded criteria donor (ECD), based on 4833 kidney recipients transplanted for the first time between 2000 and 2014. We estimated the subject-specific effect from a multivariable Cox model. We confirmed a 1.75-fold (95% confidence interval [CI] 1.53-2.00, P < .0001) increase in graft failure risk if a given patient received an ECD graft compared to a graft from a donor with standard criteria (standard criteria donor [SCD]). Complementarily, we estimated the population-average effect using propensity scores. We estimated a 1.34-fold (95% CI 1.09-1.64, P = .0049) increase in graft failure risk among ECD patients receiving an ECD graft compared to receiving a SCD graft. With a 10-year follow-up, it corresponded to a decrease of 8 months of the mean time to graft failure due to ECD transplantation (95% CI 2-14 months). The population-average relative risk due to ECD transplantation and the corresponding absolute effect seem finally not so high. Regarding the increase of quality of life in transplantation, our study constitutes an argument to extend the definition of marginality by considering more grafts at high risk and thereby enlarging the pool of kidney grafts.

Renal Operational Tolerance Is Associated With a Defect of Blood Tfh Cells That Exhibit Impaired B Cell Help.

Renal operationally tolerant patients (TOL) display a defect in B cell differentiation, with a deficiency in plasma cells. Recently described, T follicular helper (Tfh) cells play a critical role in B cell differentiation. We analyzed blood Tfh subsets in TOL and transplanted patients with stable graft function under immunosuppression (STA). We observed a reduced proportion of blood activated and highly functional Tfh subsets in TOL, without affecting Tfh absolute numbers. Functionally, Tfh cells from TOL displayed a modified gene expression profile, failed to produce interleukin-21, and were unable to induce IgG production by naive B cells. This Tfh defect is linked to a low incidence of postgraft de novo donor-specific antibody (dnDSA) immunization, suggesting that the lack of Tfh cells in TOL may induce a protolerogenic environment with reduced risk of developing dnDSA. Finally, we showed that elevated Tfh in STA precedes the occurrence of dnDSA during an alloresponse. These data provide new insights into the mechanisms of antibody response in operational tolerance. Disrupted homeostasis and impaired Tfh function in TOL could lead to a reduced risk of developing dnDSA and suggest a predictive role of blood Tfh cells on the occurrence of dnDSA in transplant recipients.

Benefits of Using CD45RA and CD28 to Investigate CD8 Subsets in Kidney Transplant Recipients.

The deleterious role of CD8 T cells in kidney graft outcome has regained interest over the years, and memory T cells are considered as one of the main hurdles to achieve transplantation success. Monitoring the CD8 immune response in transplant recipients involved a heterogeneous combination of markers, but the justification of their choice is rarely stated. Whereas the number of parameters is not an issue in phenotypic analysis, functional assays have to accommodate the cell number with the narrowing of the subset. The aim of the study was to investigate the similarities and differences of the subsets identified using three nomenclatures (CD45RA and CCR7/CD27/CD28) in kidney transplant recipients with stable graft function. We found that all three nomenclatures can identify naïve and effector memory (EM) rheumatoid arthritis T cell CD8 with similar features. Whereas CM CD8 could only be documented using CCR7 and CD45RA, the characteristics of EM CD8 will differ according to the nomenclature. We found that the use of the CD45RA and CD28 gives the benefit of examining two EM populations at early and late differentiation states. This systematic comparison provides a cohesive layout of the advantages of using these nomenclature strategies in kidney transplant recipients to guide the choice of their use.

Failure of Calcineurin Inhibitor (Tacrolimus) Weaning Randomized Trial in Long-Term Stable Kidney Transplant Recipients.

Long-term renal transplant outcome is limited by side effects of immunosuppressive drugs, particularly calcineurin inhibitor (CNI). We assumed that some patients selected for a "low immunological risk of rejection" could be eligible and benefit from a CNI weaning strategy. We designed a prospective, randomized, multicenter, double-blind placebo-controlled clinical study (Eudract: 2010-019574-33) to analyze the benefit-risk ratio of tacrolimus weaning on highly selected patients (≥4 years of transplantation, normal histology, stable graft function, no anti-HLA immunization). The primary endpoint was improvement of renal function. Fifty-two patients were scheduled in each treatment arm, placebo compared to the CNI maintenance arm. Only 10 patients were eligible and randomized. Five patients were assigned to the placebo arm and five were assigned to the tacrolimus maintenance arm. In the tacrolimus maintenance arm, all patients maintained stable graft function and no immunological events occurred. Contrastingly, in the placebo arm, all five patients had to reintroduce a full dose of tacrolimus since three of them presented an acute rejection episode (one humoral, one mixed, and one borderline) and two displayed anti-HLA antibodies without histological lesion (one donor-specific antibodies [DSA] and one non-DSA). Clearly, tacrolimus withdrawal must be avoided even in long-term highly selective stable kidney recipients.

Unique B cell differentiation profile in tolerant kidney transplant patients.

Operationally tolerant patients (TOL) display a higher number of blood B cells and transcriptional B cell signature. As they rarely develop an allo-immune response, they could display an abnormal B cell differentiation. We used an in vitro culture system to explore T-dependent differentiation of B cells into plasma cells. B cell phenotype, apoptosis, proliferation, cytokine, immunoglobulin production and markers of differentiation were followed in blood of these patients. Tolerant recipients show a higher frequency of CD20(+) CD24(hi) CD38(hi) transitional and CD20(+) CD38(lo) CD24(lo) naïve B cells compared to patients with stable graft function, correlating with a decreased frequency of CD20(-) CD38(+) CD138(+) differentiated plasma cells, suggestive of abnormal B cell differentiation. B cells from TOL proliferate normally but produce more IL-10. In addition, B cells from tolerant recipients exhibit a defective expression of factors of the end step of differentiation into plasma cells and show a higher propensity for cell death apoptosis compared to patients with stable graft function. This in vitro profile is consistent with down-regulation of B cell differentiation genes and anti-apoptotic B cell genes in these patients in vivo. These data suggest that a balance between B cells producing IL-10 and a deficiency in plasma cells may encourage an environment favorable to the tolerance maintenance.

Pretransplant sensitization against angiotensin II type 1 receptor is a risk factor for acute rejection and graft loss.

The angiotensin II type 1 receptor (AT1R) is an emerging target of functional non-HLA antibodies (Ab). We examined the potential of determining the degree of presensitization against AT1R as a risk factor for graft survival and acute rejection (AR). The study included 599 kidney recipients between 1998 and 2007. Serum samples were analyzed in a blinded fashion for anti-AT1R antibodies (AT1R-Abs) using a quantitative solid-phase assay. A threshold of AT1R-Ab levels was statistically determined at 10 U based on the time to graft failure. An extended Cox model determined risk factors for occurrence of graft failure and a first AR episode. AT1R-Abs >10 U were detected in 283 patients (47.2%) before transplantation. Patients who had a level of AT1R-Abs >10 U had a 2.6-fold higher risk of graft failure from 3 years posttransplantation onwards (p = 0.0005) and a 1.9-fold higher risk of experiencing an AR episode within the first 4 months of transplantation (p = 0.0393). Antibody-mediated rejection (AMR) accounted for 1/3 of AR, whereby 71.4% of them were associated with >10 U of pretransplant AT1R-Abs. Pretransplant anti-AT1R-Abs are an independent risk factor for long-term graft loss in association with a higher risk of early AR episodes.

A need for biomarkers of operational tolerance in liver and kidney transplantation.

Both kidney and particularly liver recipients can occasionally discontinue all immunosuppressive drugs without undergoing rejection. These patients, who maintain stable graft function off immunosuppressive drugs without clinically significant detrimental immune responses and/or immune deficits, are conventionally termed operationally tolerant and offer a unique paradigm of tolerance in humans. The immune characterization of operationally tolerant transplant recipients has recently received substantial attention. Operationally tolerant patients might exhibit a signature of tolerance that could potentially be useful to select recipients amenable to drug minimization or withdrawal. Furthermore, elucidation of the molecular pathways associated with the operational tolerance phenotype could provide novel targets for therapy. Particular emphasis has been placed on the use of blood samples and high-throughput transcriptional profiling techniques. In liver transplantation, natural killer related transcripts seem to be the most robust markers of operational tolerance, whereas enrichment in B cell-related gene expression markers has been consistently found in blood samples from operationally tolerant kidney recipients, suggesting that different mechanisms operate in the two situations. In this minireview, we summarize the main achievements of recently published reports focused on the identification of transcriptional markers of operational tolerance, we highlight their mechanistic and clinical implications and describe their methodological limitations.

BAFF and BAFF-R levels are associated with risk of long-term kidney graft dysfunction and development of donor-specific antibodies.

There are lines of evidence that B cells may play a role in transplantation. B cell activating factor, BAFF, is a homotrimer that has been shown to play a role in B cell survival, maturation and activation. To date, little is known of the role of BAFF and its receptors in transplantation. We analyzed the level of BAFF mRNA and its soluble protein, as well as transcripts coding for its receptors, BAFF-R, TACI and BCMA, in the blood of 143 patients with stable kidney transplant function 5 years or more posttransplantation. Three endpoints were analyzed: the time to renal dysfunction, the time to appearance of anti-HLA antibodies and the time to development of donor-specific antibodies. We established threshold values for BAFF and BAFF-R and showed that (1) stable patients with high BAFF-R levels had a higher risk of developing graft dysfunction, (2) patients with lower levels of BAFF transcripts or a higher level of soluble BAFF had a significantly higher risk of developing donor-specific antibodies. These data suggest that BAFF constitutes a risk factor for renal graft dysfunction and development of donor-specific antibodies. They also suggest that agents targeting BAFF-R interactions may offer new therapeutic opportunities in transplantation.

The natural history of clinical operational tolerance after kidney transplantation through twenty-seven cases.

We report here on a European cohort of 27 kidney transplant recipients displaying operational tolerance, compared to two cohorts of matched kidney transplant recipients under immunosuppression and patients who stopped immunosuppressive drugs and presented with rejection. We report that a lower proportion of operationally tolerant patients received induction therapy (52% without induction therapy vs. 78.3%[p = 0.0455] and 96.7%[p = 0.0001], respectively), a difference likely due to the higher proportion (18.5%) of HLA matched recipients in the tolerant cohort. These patients were also significantly older at the time of transplantation (p = 0.0211) and immunosuppression withdrawal (p = 0.0002) than recipients who rejected their graft after weaning. Finally, these patients were at lower risk of infectious disease. Among the 27 patients defined as operationally tolerant at the time of inclusion, 19 still display stable graft function (mean 9 ± 4 years after transplantation) whereas 30% presented slow deterioration of graft function. Six of these patients tested positive for pre-graft anti-HLA antibodies. Biopsy histology studies revealed an active immunologically driven mechanism for half of them, associated with DSA in the absence of C4d. This study suggests that operational tolerance can persist as a robust phenomenon, although eventual graft loss does occur in some patients, particularly in the setting of donor-specific alloantibody.

Comparison of transcriptional and blood cell-phenotypic markers between operationally tolerant liver and kidney recipients.

A proportion of transplant recipients can spontaneously accept their grafts in the absence of immunosuppression (operational tolerance). Previous studies identified blood transcriptional and cell-phenotypic markers characteristic of either liver or kidney tolerant recipients. However, the small number of patients analyzed and the use of different transcriptional platforms hampered data interpretation. In this study we directly compared samples from kidney and liver tolerant recipients in order to identify potential similarities in immune-related parameters. Liver and kidney tolerant recipients differed in blood expression and B-cell immunophenotypic patterns and no significant overlaps were detectable between them. Whereas some recipients coincided in specific NK-related transcripts, this observation was not reproducible in all cohorts analyzed. Our results reveal that certain immune features, but not others, are consistently present across all cohorts of operationally tolerant recipients. This provides a set of reproducible biomarkers that should be explored in future large-scale immunomonitoring trials.

Comparative transcriptional and phenotypic peripheral blood analysis of kidney recipients under cyclosporin A or sirolimus monotherapy.

Due to its low level of nephrotoxicity and capacity to harness tolerogenic pathways, sirolimus (SRL) has been proposed as an alternative to calcineurin inhibitors in transplantation. The exact mechanisms underlying its unique immunosuppressive profile in humans, however, are still not well understood. In the current study, we aimed to depict the in vivo effects of SRL in comparison with cyclosporin A (CSA) by employing gene expression profiling and multiparameter flow cytometry on blood cells collected from stable kidney recipients under immunosuppressant monotherapy. SRL recipients displayed an increased frequency of CD4 + CD25highFoxp3 + T cells. However, this was accompanied by an increased number of effector memory T cells and by enrichment in NFkB-related pro-inflammatory expression pathways and monocyte and NK cell lineage-specific transcripts. Furthermore, measurement of a transcriptional signature characteristic of operationally tolerant kidney recipients failed to detect differences between SRL and CSA-treated recipients. In conclusion, we show here that the blood transcriptional profile induced by SRL monotherapy in vivo does not resemble that of operationally tolerant recipients and is dominated by innate immune cells and NFkB-related pro-inflammatory events. These data provide novel insights on the complex effects of SLR on the immune system in clinical transplantation.

Time-dependent ROC analysis for a three-class prognostic with application to kidney transplantation.

The medical decision-making community has an extensive literature on the use of receiver operating characteristic (ROC) graphs for diagnostic testing. Heagertybiet al. have recently developed this ROC curve theory within the context of survival data (Biometrics 2000; 56:337-344). The time-dependent ROC method allows evaluating the accuracy of a marker to predict a time-dependent failure, whereas the classic methodology focuses on diagnosis. One limitation to this approach, however, is to analyse a single failure. In many medical situations, a marker can be useful to predict different competitive failures. For example in kidney transplantation, the terminal evolution can be a return to dialysis or the death of the patient. With this application in mind, our paper proposes an extension of the time-dependent ROC method for analysing the accuracy of a marker to predict two competitive events.

[Results and surgical complications of living donor nephrectomy: open vs hand-assisted laparoscopic nephrectomy]. / Résultats et complications chirurgicales de la néphrectomie donneur vivant : lombotomie vs laparoscopie manuellement assistée.

PURPOSE: Hand-assisted laparoscopic nephrectomy in living donors is a minimally invasive surgical modality. Laparoscopic nephrectomy is now a routine procedure. This study compares an initial group of patients undergoing laparoscopic live donor nephrectomy to a group of patients undergoing open donor. Donor morbidity and graft function in the laparoscopic group were compared with those in the open group. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 53 consecutive laparoscopic nephrectomy and compared them with 60 consecutive open donor nephrectomies. RESULTS: Demographic data of donors and recipients were similar in the two groups. No conversion to open surgery was necessary. Laparoscopic group patients had a shorter hospital stay compared to those undergoing open surgery. Long-term follow-up of serum creatinine levels revealed no significant differences among the two groups: at 3.6 and 12 months: 112 (+/-27) versus 122 (+/-11), 111 (+/-25) versus 119 (+/-19), 114 (+/-23) versus 122 (+/-25). There was no difference between hand-assisted laparoscopic nephrectomy (two vesico ureteral leak, three hematoma (one needed a surgical revision) and lombotomy (one vesico ureteral leak, one hematoma needed a surgical revision, two arteries stenosis). The rate of recipient ureteral stenosis in the laparoscopic and open nephrectomy groups was 0 of 39 cases and two of 60, respectively. Two vesico ureteral leak versus none appear in the lapararoscopic group. CONCLUSION: Hand-assisted laparoscopic nephrectomy in living donors is a safe procedure which presented low morbidity after surgery. This provides equal graft function equal urological complications compared to open live donor nephrectomy. This is our reference method.

[Development of a system of quality indicators for primary care prescriptions]. / Indicadores de calidad de prescripción seleccionados mediante una técnica de consenso.

OBJECTIVE: To identify and validate indicators to improve the assessment of prescribing by primary care paediatricians, incorporating the values and views of the professionals involved. MATERIAL AND METHODS: Nominal group technique, validated through a Delphi survey. PARTICIPANTS: Paediatricians and primary care pharmacists. A nominal group was formed with thirteen specialists. The question raised at the meeting was: "What indicators focusing on the drug and what indicators linked to diagnosis and treatment do you find most helpful in assessing the quality of prescription in paediatrics?", each panellist proposed indicators that were discussed and weighted on a scale from 1 to 9. The highest scored indicators were included in a two round Delphi survey, intended for all paediatricians and primary care pharmacists. MEASUREMENTS: Validity of the indicator; Indicators with a median score equal to or greater than 7 were considered valid. Degree of consensus; it was considered that there was consensus if the interquartile range was not more than 3 points. RESULTS: We generated 29 indicators focusing on the drug and 27 incorporating the diagnosis. Nineteen focusing on the drug and 13 incorporating the diagnosis were included in the survey. There was a high degree of agreement between the group and survey results. CONCLUSIONS: A set of quality indicators for paediatric prescribing has been generated using this tecnique, with consensus of a representative group of stakeholders and validated by all of them.

Looking at hospitalized persons throughout the prism of the handicap.

OBJECTIVE: To describe the disability status of non-selected hospitalized persons. METHODS AND FINDINGS: We conducted a cross-sectional survey to assess activity limitations of every person older than 18 years hospitalized in a regional university hospital covering all medical fields. Evaluators rated, on a scale from 0 to 4, 22 selected items of the International Classification of Functioning (ICF), covering the 6 following domains: learning and applying knowledge, general tasks and demands, communication, mobility, self-care, and interpersonal interactions and relationships. Univariate and multivariate analyses were performed to analyze the prevalence, severity and profile of the handicap in terms of sociodemographic characteristics and care pathways. RESULTS: Among 1572 eligible persons, 1267 (81%) were surveyed (mean age 62.7±20.4years; 655 males [51.7%]). Overall, 82% showed at least one activity limitation. For 52%, disability was severe or total for at least one ICF item. Prevalence of disabilities was higher for mobility (75%) and self-care domains (63%). Disability was strongly related to age: age older than 80years versus 18 to 44years (OR=12.8 95% CI 6.4-27.9]; P<0.01). Disability was associated with hospitalization in rehabilitation units (96%; OR=4.3 [95% CI 2.2-5.3]; P<0.01). Severe disability was associated with hospitalization in critical care units (OR=6.7 [CI 3.2-15.1]; P<0.001) and psychiatry units (OR=5.3 [CI 2.7-11.4]; P<0.001). CONCLUSION: Handicap was common in hospitalized persons, involving all 6 tested ICF activity domains, particularly mobility and self-care. This study alerts care givers, hospital administrators, and in general, people influencing health policies about the need to plan actions to reduce activity limitations of hospitalized persons, whatever the cause of the hospitalization.

Acclimatization of rats after ground transportation to a new animal facility.

This study aimed to assess the time needed by rats, which had not been previously transported, to acclimate to a new environment after 5 h of van transport, using physiological parameters as measures of acclimatization. Animal shipping boxes and transport van conditions were standardized to minimize stress factors that could be associated with transport. Heart rate (HR), body temperature and activity levels were measured in the rats before and after transport using previously implanted radio-telemetry transmitters. Body weight was also recorded. All parameters were changed significantly except for body temperature. Results suggest that rats take three days to acclimate to a new environment, as measured by the physiological parameters of body weight, HR and activity.

Design, synthesis, and structure-activity relationship studies of novel 1-[(1-acyl-4-piperidyl)methyl]-1H-2- methylimidazo[4,5-c]pyridine derivatives as potent, orally active platelet-activating factor antagonists.

Replacement of the polar head of our previous series of 1-acyl-4-[(2-methyl-3-pyridyl)-cyanomethyl]piperazines with a 2-methylimidazo[4,5-c]pyridine group has led to the identification of a new series of 1-[(1-acyl-4- piperidyl)methyl]-1H-2-methylimidazo[4,5-c]pyridine derivatives as potent, orally active platelet-activating factor (PAF) antagonists. On the basis of the general structure--activity relationship trends found for the acyl substituent in our earlier series, five groups of compounds were tested, diaryl- or alkylarylpropanoyl derivatives, their 3-hydroxy-substituted analogues, and urea, carbamate and amino acid derivatives. The optimal compound 19 UR-12670), bearing the 3,3-diphenylpropanoyl moiety, exhibited very high in vitro and in vivo potency IC50 = 0.0076 microM for the in vitro PAF-induced platelet aggregation assay, ID50 = 0.0086 mg/kg for the in vivo PAF-induced hypotension test in normotensive rats, and ID50 = 0.092 mg/kg po and 0.0008 mg/kg i.v. for the PAF-induced mortality test in mice). Compound 19 also showed long duration of activity. It gave 100% protection against PAF-induced mortality in mice 7 h after i.v. administration of a single dose of 1 mg/kg and also provided 100% inhibition of PAF-induced aggregation in dog whole blood 6 h after i.v. administration of the same dose. The lead structure 19 has been selected for in-depth pharmacological evaluation.