Clinical relevance of human leukocyte antigen antibodies in kidney transplantation from deceased donors: The North Italy Transplant program approach

Location of organ procurement and distribution organisation decisions and their impact on kidney allocations: a developing country perspective

Managing organ transplant networks is a complex task. It intertwines between locating the organ procurement and distribution organization (OPDO) (long-term decision) and allocating organs to the suitable destination (short-term decision). The literature lacks deliberation on the effect of those long-term decisions on short-term ones under the influence of clinical and non-clinical factors. This paper addresses this gap using a k-sum model for locational choice, and a discrete simulation approach for the allocation procedure for a real-life case study from a developing economy perspective. The study explores the trade-off between efficiency (distance-centric models) and equity (the result of time-centric allocation models). Our analysis of the efficiency of locational models and equity of the allocation policies reveal strong inter-dependence of both these decisions, a significant finding of this research. These findings offer an integrated model for high-level decision-makers, which can be used during the locational planning stage and provide input to design standard operating procedures for transplantation schemes.

Circulating CXCL10 and IL-6 in solid organ donors after brain death predict graft outcomes

We tested the hypothesis that circulating CXCL10 and IL-6 in donor after brain death provide independent additional predictors of graft outcome. From January 1, 2010 to June 30, 2012 all donors after brain death managed by the NITp (n = 1100) were prospectively included in this study. CXCL10 and IL-6 were measured on serum collected for the crossmatch at the beginning of the observation period. Graft outcome in recipients who received kidney (n = 1325, follow-up 4.9 years), liver (n = 815, follow-up 4.3 years) and heart (n = 272, follow-up 5 years) was evaluated. Both CXCL-10 and IL-6 showed increased concentration in donors after brain death. The intensive care unit stay, the hemodynamic instability, the cause of death, the presence of risk factors for cardiovascular disease and the presence of ongoing infection resulted as significant determinants of IL-6 and CXCL10 donor concentrations. Both cytokines resulted as independent predictors of Immediate Graft Function. Donor IL-6 or CXCL10 were associated with graft failure after liver transplant, and acted as predictors of recipient survival after kidney, liver and heart transplantation. Serum donor IL-6 and CXCL10 concentration can provide independent incremental prediction of graft outcome among recipients followed according to standard clinical practice.

Pretransplant Single Antigen Bead-Detected HLA Antibodies in Kidney Transplant Long-term Outcome: A Single-Center Cohort Experience

Single-antigen bead (SAB) platform permits the identification of antibodies not detectable by complement-dependent lymphocytotoxicity test, but their clinical significance is not completely understood. The aim of this study was to evaluate whether the presence of pretransplant SAB-detected antibodies is associated with the development of allograft failure. This is a single-center cohort study with 10-year follow-up in which 573 kidney recipients with negative pretransplant complement-dependent lymphocytotoxicity crossmatch who received transplants at the Kidney Transplant Center of Policlinico, Milan, from deceased donors between 1996 and 2005 were evaluated. Pretransplant plasma samples were retrospectively analyzed by SAB assay. Survival analyses were performed to assess the risk of allograft failures by SAB-detected antibodies. Pretransplant antibodies were found in 160 (28.0%) recipients, of whom 42 subsequently developed an allograft failure for a survival rate of 70.9% (95% confidence interval [CI), 63.5-78.4). Among those without antibodies, 58 (14.0%) returned to dialysis with a survival rate of 84.7% (95% CI, 81.0-88.4). In Cox regression analyses, patients with SAB-positivity had 2-fold higher risk of allograft failure than those who were SAB-negative (hazard ratio, 2.07; 95% CI, 1.39-2.79). Results did not change after adjustment for putative confounders. In conclusion, in this single-center cohort, 10-year allograft survival rate was significantly influenced by the presence of SAB-detected antibodies.

Association Between Cytokines and Their Receptor Antagonist Gene Polymorphisms and Clinical Risk Factors and Acute Rejection Following Renal Transplantation

BACKGROUND Acute rejection (AR) after renal transplantation affects both patient and graft survival. There is growing evidence of the genetic association between cytokine or its receptor antagonist and AR in solid organ transplantation. The objectives of this study were to investigate the role of recipient TNF β, IL-10, IL-1β, and IL-1 receptor antagonist (ra) gene polymorphism, as well as traditional clinical variables such as panel-reactive antibody (PRA) levels, donor type, and HLA mismatches in AR following renal transplantation. MATERIAL AND METHODS TNF β (+252A/G), IL-10 (-592A/C), IL-1β (-511C/T) and IL-1ra (86 bp VNTR) gene polymorphisms were determined in 195 renal allograft recipients with and without AR, using PCR. Both these genotypic variants and clinical risk factors were investigated for correlation with AR within the first year after renal transplantation. RESULTS Patients with increased pre-transplant PRA levels (P<0.001) and donor type (P=0.012) were prone to the development of AR. After adjusting for all variables of P<0.2, a PRA level >10% (OR=4.515, 95% confidence intervals=1.738-11.727, P=0.002) and the receipt of a graft from a donation after cardiac death (DCD) donor (OR=2.437, 95% confidence intervals=1.047-5.673, P=0.039) remained significantly associated with AR in a multivariate logistic regression analysis. No correlation could be found between recipients with an episode and absence of acute rejection and the gene polymorphisms of these cytokines investigated in the present study. CONCLUSIONS This study shows that the presence of increased pre-transplant levels of PRA and the receipt of a graft from DCD donor other than cytokine gene polymorphisms are significant risk factors for AR in renal transplantation. To reduce the occurrence of AR, clinicians should take necessary measures to lower the PRA levels and pay more attention to patients who received a graft from a DCD donor.

Mannose-binding lectin-2 and ficolin-2 gene polymorphisms and clinical risk factors for acute rejection in kidney transplantation

INTRODUCTION

There is growing evidence that the lectin pathway is significantly associated with acute rejection. Rare studies associated both gene polymorphisms of MBL2 and FCN2 with acute rejection after kidney transplantation. The aim of the present study was to investigate the role of the lectin gene profile and clinical risk factors such as PRA level on acute rejection in kidney transplant recipients.

METHODS

We prospectively analyzed 157 kidney transplant recipients with and without acute rejection. A total of 6 well-known functional single-nucleotide polymorphisms in the MBL2 gene and 5 in the FCN2 gene of the recipients were determined by gene sequencing. MBL2 and FCN2 genotypic variants were analyzed for association with the incidence of acute rejection within the first year after kidney transplantation.

RESULTS

After adjusting for variables of P<0.2, we found the differences in the incidence of acute rejection were only according to panel-reactive antibodies (odds ratios (OR) = 6.468, 95% confidence intervals (CI)= 2.017-20.740, P = 0.002) and the HH genotypes of MBL2 promoter -550 (OR = 2.448, 95%CI = 1.026-5.839, P = 0.044).

CONCLUSION

Panel-reactive antibodies and the HH genotypes of MBL2 promoter -550 have significant impacts on the risk of developing acute rejection after kidney transplantation.

An update on the impact of pre-transplant transfusions and allosensitization on time to renal transplant and on allograft survival

Background

Blood transfusions have the potential to improve graft survival, induce sensitization, and transmit infections. Current clinical practice is to minimize transfusions in renal transplantation candidates, but it is unclear if the evidence continues to support pre-transplant transfusion avoidance. Changes in the Medicare prospective payment system may increase transfusion rates. Thus there is a need to re-evaluate the literature to improve the management options for renal transplant candidates.

Methods

A review applying a systematic approach and conducted using MEDLINE^®, Embase^®, and the Cochrane Library for English-language publications (timeframe: 01/1984–03/2011) captured 180 studies and data from publically available registries and assessed the impact of transfusions on allosensitization and graft survival, and the impact of allosensitization on graft survival and wait time.

Results

Blood transfusions continued to be a major cause of allosensitization, with allosensitization associated with increased rejection and graft loss, and longer wait times to transplantation. Although older studies showed a beneficial effect of transfusion on graft survival, this benefit has largely disappeared in the post-cyclosporine era due to improved graft outcomes with current practice. Recent data suggested that it may be the donor-specific antibody component of allosensitization that carried the risk to graft outcomes.

Conclusions

Results of this review indicated that avoiding transfusions whenever possible is a sound management option that could prevent detrimental effects in patients awaiting kidney transplantation.

Luminex and antibody detection in kidney transplantation

Preformed anti-human leukocyte antigen (HLA) antibodies have a negative effect on kidney transplantation outcome with an increased rejection rate and reduction in survival. Posttransplantation production of donor-specific anti-HLA antibodies is indicative of an active immune response and risk of transplantation rejection. For many years the primary technique for anti-HLA antibody detection was complement-dependent cytotoxicity (CDC), which has been integrated by solid-phase assays as HLA antigen-coated bead methods (Luminex). This new technological approach has allowed identification of anti-HLA antibodies, not detectable using conventional CDC method, in patients awaiting kidney transplantation. Moreover, use of Luminex technology has enabled better definition of acceptable or unacceptable antigens favoring transplantation in highly immunized patients. However, there are still many unresolved issues, including the clinical relevance of antibodies detected with this system.

(AT) repeat in the 3' untranslated region of the CTLA-4 gene and susceptibility to acute allograft rejection in Tunisian renal transplantation

Allograft rejection is an immune response relying on the proliferation and the differentiation of T cells. CTLA-4 is a co-stimulatory molecule, expressed on activated T lymphocytes, which has been shown to play a crucial role in the down-regulation of T-cell activation. Herein, we have examined the impart of a genetic marker in the CTLA-4 gene on renal transplant outcomes. A cohort of 144 renal recipients and 100 healthy subjects were genotyped by the fragments analysis method using an automated sequencer. Patients were classified into two groups: Group I included 31 HLA-identical haplotype allograft recipients and Group II, 113 showing one or more HLA haplotype mismatches. Forty patients (27.78%) developed at least one acute rejection episode (ARE): 9 in Group I and 31 in Group II. Before transplantation, 20 patients were lymphocytotoxic antibodies (LCT) positive: 4 Group I, 2 of whom developed an ARE, and sixty in Group II, including 8 with an ARE. The occurrence of an ARE was associated with the presence of LCT before transplantation among the entire cohort of patients (P = .032) and among Group II (P = .037). The allelic frequencies of (AT)n polymorphism did not reveal significant differences between patients and controls. The most prevalent alleles were the 88 bp (51% in controls and 44.44% in patients) and the 106 bp (8% and 10.76%, respectively). We noticed an increase of the 120 bp allele frequency among patients who had undergone an ARE compared with those who did not display this complication (8.75% vs 3.85%). Likewise, among LCT-negative Group I, recipients the incidence of the 120 bp allele was higher in ARE than non-ARE patients. Although the differences were not statistically significant, we propose that the 120 bp allele of the CTLA-4 gene (AT)n microsatellite a predisposes to acute rejection episodes in renal transplantation.