Jacqueline van de Wetering

The impact of transforming growth factor-β1 gene polymorphism on end-stage renal failure after heart transplantation

Background. Nephrotoxicity is a major side effect of calcineurin inhibitors (CNI). Earlier we reported 8% of our heart transplant recipients reaching end-stage renal failure (ESRF). Now, with an extended follow up of 20 years, we re-evaluated the development of ESRF and studied its influence on survival and the impact of polymorphisms in codon 10 and 25 of the promoter region of transforming growth factor (TGF)-&bgr; on the risk of ESRF. Methods. In all, 465 patients were transplanted between June 1984 and June 2005. All were on maintenance CNI treatment. Development of ESRF was studied in 402/465 (86.5%) patients surviving at least one year. Their median follow up was eight years, total observation time of 3,414 years. TGF-&bgr; polymorphisms in codon 10 (Leu to Pro) and codon 25 (Arg to Pro) were analyzed with real-time polymerase chain reaction in a cohort of 237 patients, with an observation time of 2,329 years. Results. Ten-year survival of patients surviving at least one year was 58.5%. Seventy-three patients (18.2%) developed ESRF. Dialysis-free survival was 60% at 15 years. The relative risk for ESRF in Pro10 carriers was 2.9 (CI 1.5–5.8) compared to patients with the Leu/Leu10 genotype (P=0.002), while Pro25 carriers had a RR of 2.6 (CI 1.4–4.8) compared to the Arg/Arg25 genotype (P=0.002). Survival of patients with ESRF was 1.5 years (median). Conclusion. We found a highly significant association between TGF-&bgr; polymorphisms and CNI induced ESRF after heart transplantation (HTx). Pro carriers of either codon 10 or 25 had a 2.6 to 2.9 times increased risk of developing ESRF. As ESRF after HTx results in high mortality rates these patients should no longer receive CNI-based immunosuppression.

Patient Survival After the Diagnosis of Cancer in Renal Transplant Recipients: A Nested Case-control Study

Introduction. Malignancy is a well-known complication after renal transplantation. We studied the influence of cancer on patient survival in the Dutch renal transplant population in a nested case-controlled analysis. Methods. Between March 1966 and May 2008, 15,227 renal transplantations in 12,805 recipients were registered in the Netherlands Organ Transplant Registry database. Total follow-up was 89,651 person years. We performed an analysis of patient and graft survival both from the day of transplantation and the diagnosis of cancer in recipients with invasive cancer. Recipients without invasive cancer, matched for gender, age, and year of transplantation, served as a control group. For the survival analysis after the diagnosis of cancer, the matched control group consisted of patients with a functioning graft at the moment the index patient was diagnosed with cancer. Results. Cancer had been registered in 908 (7.1%) patients, 630 (69%) of them died with functioning kidney, 510 (81%) because of their malignancy (at 8.2 years after transplantation, median). The median patient survival after transplantation was 11.9 vs. 16.8 years in the study and control group, respectively (P<0.001). The median patient and graft survival after the diagnosis of cancer was 2.1 vs. 8.3 (P<0.001) and 25 vs. 22.4 (P<0.001) years in the study and control group, respectively. Conclusion. Mortality because of cancer is observed at a significantly later time after transplantation compared with mortality because of the other main lethal complications. It significantly affects life expectancy and carries a poor prognosis with a limited survival after diagnosis.

Ethnically diverse populations and their participation in living kidney donation programs

Background. The number of living donor kidney transplantations increases steeply in Europeans, whereas the non-Europeans are dependent on deceased donor transplantations. We wondered whether a low attendance or a high decline of potential non-European donors could explain this difference. Methods. This retrospective study includes all 1059 potential living kidney donors who attended our pretransplant clinic between 2000 and 2007. Potential donors were divided according to eight countries of origin: African, Dutch Antillean, European, Indonesian, Moroccan, Surinamese, Turkish, and various countries. In addition to direct living donation, alternative living donation programs are operational in our center: kidney exchange, domino paired, ABO incompatible, and anonymous donation. Results. European donors predominated in both the potential (79%) and the actual donor populations (85%). Actual donors comprised 39% of non-European and 59% of the European potential donors (P<0.001). Participation in alternative donation programs is significantly less among non-European donors in comparison with European donors (3.6% vs. 12.6%, P<0.001). In all non-European populations, genetically related donors predominated, whereas genetically related and unrelated donors were equally represented in the European potential donor population (P<0.001). Partners were under-represented in all non-European populations (P<0.001). The attitude and behavior of non-Europeans with the longest duration of stay in the Netherlands were closest to that of the Europeans. The population with the shortest stay differed the most. This could possibly be attributed to integration. Conclusion. There are less non-European donors than expected based on the population composition. Living donor characteristics are different between Europeans and non-Europeans. The reasons for the difference deserve investigation.

Accumulation of unfavorable clinical and socioeconomic factors precludes living donor kidney transplantation

Background. In the past 30 years, the number of living donor kidney transplantations has increased considerably and nowadays outnumbers the deceased donor transplantations in our center. We investigated which socioeconomic and clinical factors influence who undergoes living or deceased donor kidney transplantation. Methods. This retrospective study included all 1338 patients who received a kidney transplant between 2000 and 2011 in the Erasmus MC Rotterdam. Clinical and socioeconomic variables were combined in our study. Clinical variables were recipient age, gender, ethnicity, original disease, retransplants, ABO blood type, panel-reactive antibody, previous treatment, and transplantation year. Each recipients postcode was linked to a postcode area information data base, to extract demographic information on urbanization level, percentage non-Europeans in the area, income, and housing value. Chi-square, analysis of variance, and univariate and multivariate logistic regression analyses were performed. Results. There were significant differences between the recipients of a living versus deceased donor kidney transplantation. In multivariate logistic regression analyses, 10 variables had a significant influence on the chance of receiving living donor kidney transplantation. Clinical and socioeconomic factors had an independent influence on this chance. Patients with ABO blood type O and B have smaller chances. Highly sensitized and elderly patients have smaller chances especially when combined with a collection of other unfavorable factors. Accumulation of unfavorable factors in non-Europeans prevents their participation in living donation programs. Conclusion. Both clinical and socioeconomic factors are associated with participation in living or deceased donor kidney transplantation. This study highlights the populations that would benefit from educational intervention regarding living donor transplantation.

The relative importance of donor age in deceased and living donor kidney transplantation

In deceased donor kidney transplantation donor age is known to influence graft survival. The influence of living donor age on graft survival is questioned. We compared the influence of living and deceased donor age on the outcome of renal transplantation. All 1821 transplants performed in our center between 1990 and 2009 were included in the analysis. Observation was until April 2012. A total of 941 patients received a deceased donor kidney and 880 a living donor kidney. In multivariate Cox analysis, recipient age, maximum and current panel reactive antibodies, transplant year, HLA‐mismatches, donor age, donor gender, donor type, delayed graft function, and calcineurin inhibitor (CNI) and prednisone as initial immunosuppression were found to have a significant influence on death‐censored graft failure. The influence of both living and deceased donor age followed a J‐shaped curve, above 30u2003years the risk increased with increasing age. Donor type and donor age had an independent influence. The graft failure risk of deceased donor transplantation is almost twice that of living donor transplantation so that a 60‐year‐old living donor kidney has the same graft failure risk as a 20‐year‐old deceased donor kidney.

Persistently low transplantation rate of ABO blood type O and highly sensitised patients despite alternative transplantation programs

ABO blood type O and highly sensitised patients have the smallest chance to receive kidney transplantation. Do alternative donation programs increase this chance? In the period studied: 2323 patients were enlisted on the Rotterdam waiting list for a renal transplantation: 435 patients still waiting (WL), 464 delisted without transplantation (DWT). 1424 received deceased donor (DD, 535) or living donor (LD, 889, including 204 alternative) transplantation. Alternative LD programs in our centre are: paired kidney‐exchange, altruistic with domino‐paired donation and ABO‐incompatible donation (ABOi). Compared to populations not transplanted, blood type O recipients are significantly underrepresented in DD and all LD transplantation populations, except the ABOi program. Highly sensitised patients are overrepresented in DD, but underrepresented in all LD transplantation populations. The high transplantation rate of highly sensitised patients was the result of Eurotransplant Acceptable mismatch program (AM). The LD ABOi and DD AM programs are the only alternative donation programs favourable for patients with low chances. While the contribution of direct LD transplantations will increase in time, the relative success rate of low‐chance patients will decrease. Beside increasing LD ABOi transplantation, a new DD allocation model favouring both highly immunised and blood type O patients is essential.

Discontinuation of calcineurin inhibitors treatment allows the development of FOXP3+ regulatory T-cells in patients after kidney transplantation

van de Wetering J, Koumoutsakos P, Peeters A, van der Mast BJ, de Kuiper P, IJzermans JNM, Weimar W, Baan CC. Discontinuation of calcineurin inhibitors treatment allows the development of FOXP3+ regulatory T‐cells in patients after kidney transplantation.u2028Clin Transplant 2011: 25: 40–46.

Successful Tapering of Immunosuppression to Low-Dose Monotherapy Steroids After Living-Related Human Leukocyte Antigen-Identical Renal Transplantation

Background. Living-related (LR) human leukocyte antigen (HLA)-identical renal transplant (RTx) recipients often receive standard immunosuppression, despite the absence of mismatched major HLA-antigens and the known complications of long-term use of immunosuppression. No data are available on the need for immunosuppression for these specific patients. We wondered whether their immunosuppressive load could be radically reduced. Method. Between November 1982 and November 2005, 83 LR HLA-identical RTx were performed in our center. Their unadjusted graft survival was 74% at 10 years. In 29 patients (median time after transplantation 5.6 [range 1.0–21.4] years) with stable uncompromised renal function, we tapered their immunosuppression from triple or dual therapy to prednisolone 5 mg/day. Follow up on prednisolone monotherapy was at least 24 months. Results. In 27 of 29 patients reduction of immunosuppression to prednisolone monotherapy was uneventful. One patient, using dual therapy, developed JC-virus nephropathy resulting in graft loss. One refused further discontinuation of his medication. Four (15%) of the 27 patients on monotherapy developed biopsy-proven recurrence of their original disease. Only one of them showed a transient decline in renal function. One additional patient developed minor proteinuria and a rise in serum creatinine level, as a result of chronic urinary tract infections. The remaining 23 of 27 patients (85%) had an uneventful follow up during 24 months prednisolone monotherapy. Conclusion. We conclude that HLA-identical LR RTx recipients who are at least 1 year after transplantation might be treated with low-dose steroid monotherapy. Close surveillance of patients for recurrence of their original disease is recommended to allow for potential early therapeutic intervention.

The human alloreactive CD4+ T-cell repertoire is biased to a Th17 response and the frequency is inversely related to the number of HLA class II mismatches

Estimates of precursor frequency and assessment of functional characteristics of alloreactive CD4+ T cells are all biased by the need for long-term culture. In this study, direct visualization of human alloreactive CD4+ T cells on the single-cell level was achieved using cell surface expression of CD154 as a tool for identification. The average frequency of alloreactive CD154+CD4+ T cells among peripheral blood CD4+ T cells was 0.1%, with half of the cells displaying a naive phenotype. The proliferation capacity and expression of cytokines after allogeneic stimulation resided in these CD154+CD4+ T cells. The repertoire of alloreactive CD4+ T cells was biased to a Th17 response, and on average 24% of alloreactive CD154+CD4+ memory T cells produced interleukin-17 (IL-17) after polyclonal stimulation. Unexpectedly, mixed cell cultures from human leukocyte antigen (HLA)-identical donors also generated alloreactive CD154+CD4+ T cells and yielded the highest frequency compared with HLA-nonidentical combinations. Therefore, reactivity to minor histocompatibility antigens between HLA-identical subjects appears to be relatively common. Alloreactive HLA-identical T cells did not proliferate or express cytokines, but were driven to proliferation in the presence of exogenous IL-2.

T-Cell Reactivity During Tapering of Immunosuppression to Low-Dose Monotherapy Prednisolone in HLA-Identical Living-Related Renal Transplant Recipients

Background. In many transplant centers, human leukocyte antigen (HLA)-identical living-related (LR) renal transplant recipients receive standard maintenance immunosuppression from 1 year after transplantation. We questioned whether discontinuation of azathioprine (AZA) or mycophenolate mofetil (MMF) influenced T-cell reactivity, circulating dendritic cell (DC) subsets numbers and their maturation status. Methods. Twenty-nine HLA-identical LR renal transplant recipients were withdrawn from AZA or MMF. Thereafter, the patients received only prednisolone. T-cell reactivity was determined by interferon-&ggr; (n=23), interleukin (IL)-10 (n=16), and granzyme B (n=10) Elispot assays. Circulating DC subset numbers and their maturation status determined by CCR2, CCR5, CCR7, and CD83 expression were measured by flow cytometry (n=12). Results. The number of donor, third-party, and tetanus toxoid-reactive interferon-&ggr; and granzyme-B producing cells was not affected after withdrawal of immunosuppression. Discontinuation of AZA or MMF resulted in significant increased numbers of third-party (P=0.003) and tetanus toxoid-reactive (P=0.008) IL-10 producing cells, and a trend in higher numbers of donor-reactive IL-10 producing cells (P=0.06). No effect was found on the number of circulating DC subsets, but DC was shifted toward a more mature phenotype. Conclusions. In HLA-identical LR renal transplant recipients, therapy with AZA and MMF suppress the IL-10 production and the maturation of DC. This suggests that these immunosuppressants may hinder suppression of immune responses in general, including allogeneic responses.