Conclusions sur les avancées en transplantation

Les excellents résultats de la transplantation au cours des dernières décennies ont mis en évidence de nouveaux défis à résoudre dans les années à venir : (1) Modifier les conditions de conservation des organes prélevés pour en améliorer la qualité. (2) Modifier les stratégies en prenant en compte le déficit immunitaire devant de nouvelles infections comme celle à Sars CoV-2. (3) Mieux comprendre les mécanismes du rejet chronique et en particulier le rôle de l’immunité innée. (4) Repenser les traitements immunosuppresseurs pour prévenir et traiter les rejets chroniques.

Tissue Factor Activity of Syncytiotrophoblast Plasma Membranes and Tumoral Trophoblast Cells in Culture

During pregnancy, important modifications of hemostasis occur resulting in mothers in hypercoagulability and the role of placental cells such as trophoblast cells has been hypothesized. In this study, we first showed that syncytiotrophoblast plasma membranes, isolated from normal human placenta, expressed a strong tissue factor (TF) activity. We then studied TF activity of two continuous trophoblast cell lines (JEG-3 and BeWo) in comparison to human umbilical vein endothelial cells (HUVEC) and transformed human endothelial cells (ECV-304). TF assays were performed on intact detached confluent cells. Unstimulated JEG-3 and BeWo cells exhibited a very high TF activity which slightly increased after 2 to 4 h TNF-α stimulation. In contrast, HUVEC and ECV-304 had a lower basal TF activity which was mainly inducible by TNF-a, with a maximum effect after 4 to 6 h stimulation. For both cell types, TF activity was decreased to basal value after 16-hour TNF-α stimulation. These results support that trophoblast cells are able to express TF but the involvement of this property in the hemostatic physiological changes observed during pregnancy, remains to be demonstrated.

Reduction of Extended-Release Tacrolimus Dose in Low-Immunological-Risk Kidney Transplant Recipients Increases Risk of Rejection and Appearance of Donor-Specific Antibodies: A Randomized Study

The aim of this study (ClinicalTrials.gov, NCT01744470) was to determine the efficacy and safety of two different doses of extended-release tacrolimus (TacER) in kidney transplant recipients (KTRs) between 4 and 12 mo after transplantation. Stable steroid-free KTRs were randomized (1:1) after 4 mo: Group A had a 50% reduction in TacER dose with a targeted TacER trough level (C₀ ) >3 μg/L; group B had no change in TacER dose (TacER C₀ 7-12 μg/L). The primary outcome was estimated GFR at 1 year. Of 300 patients, the intent-to-treat analysis included 186 patients (group A, n = 87; group B, n = 99). TacER C₀ was lower in group A than in group B at 6 mo (4.1 ± 2.7 vs. 6.7 ± 3.9 μg/L, p < 0.0001) and 12 mo (5.6 ± 2.0 vs. 7.4 ± 2.1 μg/L, p < 0.0001). Estimated GFR was similar in both groups at 12 mo (group A, 56.0 ± 17.5 mL/min per 1.73 m²; group B, 56.0 ± 22.1 mL/min per 1.73 m²). More rejection episodes occurred in group A than group B (11 vs. 3; p = 0.016). At 1 year, subclinical inflammation occurred more frequently in group A than group B (inflammation score [i] >0: 21.4% vs. 8.8%, p = 0.047; tubulitis score [t] >0: 19.6% vs. 8.7%, p = 0.076; i + t: 1.14 ± 1.21 vs. 0.72 ± 1.01, p = 0.038). Anti-HLA donor-specific antibodies appeared only in group A (6 vs. 0 patients, p = 0.008). TacER C₀ should be maintained >7 μg/L during the first year after transplantation in low-immunological-risk, steroid-free KTRs receiving a moderate dose of mycophenolic acid.

Genome-Wide Association Study of Acute Renal Graft Rejection

Acute renal rejection is a major risk factor for chronic allograft dysfunction and long-term graft loss. We performed a genome-wide association study to detect loci associated with biopsy-proven acute T cell-mediated rejection occurring in the first year after renal transplantation. In a discovery cohort of 4127 European renal allograft recipients transplanted in eight European centers, we used a DNA pooling approach to compare 275 cases and 503 controls. In an independent replication cohort of 2765 patients transplanted in two European countries, we identified 313 cases and 531 controls, in whom we genotyped individually the most significant single nucleotide polymorphisms (SNPs) from the discovery cohort. In the discovery cohort, we found five candidate loci tagged by a number of contiguous SNPs (more than five) that was never reached in iterative in silico permutations of our experimental data. In the replication cohort, two loci remained significantly associated with acute rejection in both univariate and multivariate analysis. One locus encompasses PTPRO, coding for a receptor-type tyrosine kinase essential for B cell receptor signaling. The other locus involves ciliary gene CCDC67, in line with the emerging concept of a shared building design between the immune synapse and the primary cilium.

Mycophenolate mofetil in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis: a prospective pharmacokinetics and clinical study

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) treatment strategy is based on immunosuppressive agents. Little information is available concerning mycophenolic acid (MPA) and the area under the curve (AUC) in patients treated for AAV. We evaluated the variations in pharmacokinetics for MPA in patients with AAV and the relationship between MPA-AUC and markers of the disease. MPA blood concentrations were measured through the enzyme-multiplied immunotechnique (C(0), C(30), C(1), C(2), C(3), C(4), C(6) and C(9)) to determine the AUC. Eighteen patients were included in the study. The median (range) MPA AUC(0-12) was 50·55 (30·9-105·4) mg/h/l. The highest coefficient of determination between MPA AUC and single concentrations was observed with C(3) (P < 0·0001) and C(2) (P < 0·0001) and with C(4) (P < 0·0005) or C(0) (P < 0·001). Using linear regression, the best estimation of MPA AUC was provided by a model including C(30), C(2) and C(4): AUC = 8·5 + 0·77 C(30) + 4·0 C(2) + 1·7 C(4) (P < 0·0001). Moreover, there was a significant relationship between MPA AUC(0-12) and lymphocyte count (P < 0·01), especially CD19 (P < 0·005), CD8 (P < 0·05) and CD56 (P < 0·05). Our results confirm the interindividual variability of MPA AUC in patients treated with MMF in AAV and support a personalized therapy according to blood levels of MPA.

Bifidobacteria BbC50 Fermentation Products Induce Human Cd4+ Regulatory T Cells with Antigen-Specific Activation and Bystander Suppression

Probiotic bacteria have been shown to have health benefits in various situations (inflammation, allergy, infection). We previously showed that a bacteria-free fermentation product of Bifidobacterium breve C50 (BbC50sn) induced high IL-10 secretion by human dendritic cells. As IL-10 is a regulatory cytokine, the aim of the present study was to examine whether DCs cultured in the presence of BbC50sn could induce regulatory T cells in an allogeneic context. Purified CD4+CD25− human T cells were co-cultured with allogeneic BbC50sn-treated dendritic cells for 4 weeks. The T cell population (BbC50sn-T) was analysed both at phenotypical and functional [ability to inhibit a mixed lymphocyte reaction (MLR)] levels. We showed that T lymphocytes acquired phenotype characteristics of regulatory T cells after 4 weeks of co-culture with BbC50sn-DCs, and inhibited in vitro T lymphocyte proliferation and IFN-γ production in an MLR. Transwell experiments demonstrated that this suppressive activity was not T cell contact-dependent but probably mediated by a soluble factor. Although BbC50sn-T cells secreted significant amounts of IL-10 and TGF-β, their suppressive effect is most likely not mediated through these cytokines. This is, to our knowledge, the first demonstration of in vitro regulatory T cell induction by a bacteria-free fermentation product in an allogeneic context.

CMV infection in the donor and increased kidney graft loss: impact of full HLA-I mismatch and posttransplantation CD8(+) cell reduction

Despite a large body of literature, the impact of chronic cytomegalovirus (CMV) infection in donor on long-term graft survival remains unclear, and factors modulating the effect of CMV infection on graft survival are presently unknown. In this retrospective study of 1279 kidney transplant patients, we analyzed long-term graft survival and evolution of CD8(+) cell population in donors and recipients by CMV serology and antigenemia status. A positive CMV serology in the donor was an independent risk factor for graft loss, especially among CMV-positive recipients (R(+) ). Antigenemia was not a risk factor for graft loss and kidneys from CMV-positive donors remained associated with poor graft survival among antigenemia-free recipients. Detrimental impact of donor's CMV seropositivity on graft survival was restricted to patients with full HLA-I mismatch, suggesting a role of CD8(+) cells. In R(+) patients with positive CMV antigenemia during the first year, CD8(+) cell count did not increase at 2 years posttransplantation, in contrast to R(-) recipients. In addition, marked CD8(+) -cell decrease was a risk factor of graft failure in these patients. This study identifies HLA-I full mismatch and a decrease of CD8(+) cell count at 2 years as important determinants of CMV-associated graft loss.

Terminal complement inhibitor eculizumab in atypical hemolytic-uremic syndrome

BACKGROUND

Atypical hemolytic-uremic syndrome is a genetic, life-threatening, chronic disease of complement-mediated thrombotic microangiopathy. Plasma exchange or infusion may transiently maintain normal levels of hematologic measures but does not treat the underlying systemic disease.

METHODS

We conducted two prospective phase 2 trials in which patients with atypical hemolytic-uremic syndrome who were 12 years of age or older received eculizumab for 26 weeks and during long-term extension phases. Patients with low platelet counts and renal damage (in trial 1) and those with renal damage but no decrease in the platelet count of more than 25% for at least 8 weeks during plasma exchange or infusion (in trial 2) were recruited. The primary end points included a change in the platelet count (in trial 1) and thrombotic microangiopathy event-free status (no decrease in the platelet count of >25%, no plasma exchange or infusion, and no initiation of dialysis) (in trial 2).

RESULTS

A total of 37 patients (17 in trial 1 and 20 in trial 2) received eculizumab for a median of 64 and 62 weeks, respectively. Eculizumab resulted in increases in the platelet count; in trial 1, the mean increase in the count from baseline to week 26 was 73×10(9) per liter (P<0.001). In trial 2, 80% of the patients had thrombotic microangiopathy event-free status. Eculizumab was associated with significant improvement in all secondary end points, with continuous, time-dependent increases in the estimated glomerular filtration rate (GFR). In trial 1, dialysis was discontinued in 4 of 5 patients. Earlier intervention with eculizumab was associated with significantly greater improvement in the estimated GFR. Eculizumab was also associated with improvement in health-related quality of life. No cumulative toxicity of therapy or serious infection-related adverse events, including meningococcal infections, were observed through the extension period.

CONCLUSIONS

Eculizumab inhibited complement-mediated thrombotic microangiopathy and was associated with significant time-dependent improvement in renal function in patients with atypical hemolytic-uremic syndrome. (Funded by Alexion Pharmaceuticals; C08-002 ClinicalTrials.gov numbers, NCT00844545 [adults] and NCT00844844 [adolescents]; C08-003 ClinicalTrials.gov numbers, NCT00838513 [adults] and NCT00844428 [adolescents]).

Five-year results of a randomized trial comparing de novo sirolimus and cyclosporine in renal transplantation: the SPIESSER study

Calcineurin inhibitors improve acute rejection rates and short-term graft survival in renal transplantation, but their continuous use may be deleterious. We evaluated the 5-year outcomes of sirolimus (SRL) versus cyclosporine (CsA) immunosuppressive treatment. This observational study was an extension of the SPIESSER study where deceased donor kidney transplant recipients were randomized before transplantation to a SRL- or CsA-based regimen and followed up 1 year. Data from 131 (63 SRL, 68 CsA) out of 133 patients living with a functional graft at 1 year were collected retrospectively at 5 years posttransplant. Seventy percent of CsA patients versus 54% of SRL patients were still on the allocated treatment at 5 years (p = 0.091), most discontinuations in each group being due to safety issues. In intent-to-treat, mean MDRD eGFR was higher with SRL: 54.2 versus 45.3 mL/min with CsA (p = 0.019); SRL advantage was greater in on-treatment analyses. There were no differences for patient survival (p = 0.873), graft survival (p = 0.121) and acute rejection (p = 0.284). Adverse events were more frequent with SRL (80% vs. 60%, p = 0.015). Results confirmed the high SRL discontinuation rate due to adverse events. Nevertheless, a benefit was evidenced on renal function in patients (more than 50%) still on treatment at 5 years.

Epidemiology of posttransplant lymphoproliferative disorders in adult kidney and kidney pancreas recipients: report of the French registry and analysis of subgroups of lymphomas

A registry of posttransplant lymphoproliferative disorders (PTLD) was set up for the entire population of adult kidney transplant recipients in France. Cases of PTLD were prospectively enrolled between January 1, 1998, and December 31, 2007. Ten-year cumulative incidence was analyzed in patients transplanted after January 1, 1989. PTLD risk factors were analyzed in patients transplanted after January 1, 1998 by Cox analysis. Cumulative incidence was 1% after 5 years, 2.1% after 10 years. Multivariate analysis showed that PTLD was significantly associated with: older age of the recipient 47-60 years and >60 years (vs. 33-46 years, adjusted hazard ratio (AHR) = 1.87, CI = 1.22-2.86 and AHR = 2.80, CI = 1.73-4.55, respectively, p < 0.0001), simultaneous kidney-pancreas transplantation (AHR = 2.52, CI = 1.27-5.01 p = 0.008), year of transplant 1998-1999 and 2000-2001 (vs. 2006-2007, AHR = 3.36, CI = 1.64-6.87 and AHR = 3.08, CI = 1.55-6.15, respectively, p = 0.003), EBV mismatch (HR = 5.31, CI = 3.36-8.39, p < 0.001), 5 or 6 HLA mismatches (vs. 0-4, AHR = 1.54, CI = 1.12-2.12, p = 0.008), and induction therapy (AHR = 1.42, CI = 1-2.02, p = 0.05). Analyses of subgroups of PTLD provided new information about PTLD risk factors for early, late, EBV positive and negative, polymorphic, monomorphic, graft and cerebral lymphomas. This nationwide study highlights the increased risk of PTLD as long as 10 years after transplantation and the role of cofactors in modifying PTLD risk, particularly in specific PTLD subgroups.

Immunosuppressant regimen based on sirolimus decreases aortic stiffness in renal transplant recipients in comparison to cyclosporine

Whether or not a cyclosporine A (CsA)-free immunosuppressant regimen based on sirolimus (SRL) prevents aortic stiffening and improves central hemodynamics in renal recipients remains unknown. Forty-four patients (48 ± 2 years) enrolled in the CONCEPT trial were randomized at week 12 (W12) to continue CsA or switch to SRL, both associated with mycophenolate mofetil. Carotid systolic blood pressure (cSBP), pulse pressure (cPP), central pressure wave reflection (augmentation index, AIx) and carotid-to-femoral pulse-wave velocity (PWV: aortic stiffness) were blindly assessed at W12, W26 and W52 together with plasma endothelin-1 (ET-1), thiobarbituric acid-reactive substances (TBARS) and superoxide dismutase (SOD) and catalase erythrocyte activities. At W12, there was no difference between groups. At follow-up, PWV, cSBP, cPP and AIx were lower in the SRL group. The difference in PWV remained significant after adjustment for blood pressure and eGFR. In parallel, ET-1 decreased in the SRL group, while TBARS, SOD and catalase erythrocyte activities increased in both groups but to a lesser extent in the SRL group. Our results demonstrate that a CsA-free regimen based on SRL reduces aortic stiffness, plasma endothelin-1 and oxidative stress in renal recipients suggesting a protective effect on the arterial wall that may be translated into cardiovascular risk reduction.

Efficacy and safety of early cyclosporine conversion to sirolimus with continued MMF-four-year results of the Postconcept study

Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function. We previously reported that conversion from cyclosporine A (CsA) to sirolimus (SRL) 3 months after transplantation significantly improved renal function at 1 year. In the Postconcept trial, 77 patients in the SRL group and 85 in the CsA group were followed for 48 months. Renal function (Cockcroft and Gault) was significantly better at month 48 (M48) in the SRL group both in the intent-to-treat population (ITT): 62.6 mL/min/1.73 m(2) versus 57.1 mL/min/1.73 m(2) (p = 0.013) and in the on-treatment population (OT): 67.5 mL/min/1.73 m(2) versus 57.4 mL/min/1.73 m(2) (p = 0.002). Two biopsy proven acute rejection episodes occurred after M12 in each group. Graft and patient survival were comparable (graft survival: 97.4 vs. 100%; patient survival: 97.4 vs. 97.6%, respectively). The incidence of new-onset diabetes was numerically increased in the SRL group (7 vs. 2). In OT, three cancers occurred in the SRL group versus nine in the CsA group and mean proteinuria was increased in the SRL group (0.42 ± 0.44 vs. 0.26 ± 0.37; p = 0.018). In summary, the renal benefits associated with conversion of CsA to SRL, at 3 months posttransplantation, in combination with MMF were maintained for 4 years posttransplantation.

High dose epoetin beta in the first weeks following renal transplantation and delayed graft function: Results of the Neo-PDGF Study

Erythropoietin promotes nephroprotection in animal models of ischemia-reperfusion injury. Neorecormon and Prevention of Delayed Graft Function (Neo-PDGF) is a French open-label multicenter randomized study to evaluate the effect of high doses of epoetin beta (EPO-beta) during the first 2 weeks of renal transplantation on renal function in patients at risk for delayed graft function (DGF). One hundred and four patients were included in the study. Patients randomized in treatment group (A) received four injections of EPO-beta (30.000 UI each), given before surgery and at 12 h, 7 days and 14 days posttransplantation. Patients randomized in control group (B) did not receive EPO-beta. Immunosuppression included induction with basiliximab and maintenance therapy with steroids, mycophenolate mofetil and tacrolimus. At 1 month posttransplant, the estimated glomerular filtration rate (MDRD formula) was 42.5 +/- 19.0 mL/min in the EPO-beta group and 44.0 +/- 16.3 mL/min in the control group (p = ns). The frequency of DGF was similar in both groups (32% vs. 38.8%; p = ns). No difference in the incidence of serious adverse events was observed. (ClinicalTrials.gov number, NCT00815867.).

The efficacy and safety of 200 days valganciclovir cytomegalovirus prophylaxis in high-risk kidney transplant recipients

Late-onset cytomegalovirus (CMV) disease is a significant problem with a standard 3-month prophylaxis regimen. This multicentre, double-blind, randomized controlled trial compared the efficacy and safety of 200 days' versus 100 days' valganciclovir prophylaxis (900 mg once daily) in 326 high-risk (D+/R-) kidney allograft recipients. Significantly fewer patients in the 200-day group versus the 100-day group developed confirmed CMV disease up to month 12 posttransplant (16.1% vs. 36.8%; p < 0.0001). Confirmed CMV viremia was also significantly lower in the 200-day group (37.4% vs. 50.9%; p = 0.015 at month 12). There was no significant difference in the rate of biopsy-proven acute rejection between the groups (11% vs. 17%, respectively, p = 0.114). Adverse events occurred at similar rates between the groups and the majority were rated mild-to-moderate in intensity and not related to study medication. In conclusion, this study demonstrates that extending valganciclovir prophylaxis (900 mg once daily) to 200 days significantly reduces the incidence of CMV disease and viremia through to 12 months compared with 100 days' prophylaxis, without significant additional safety concerns associated with longer treatment. The number needed to treat to avoid one additional patient with CMV disease up to 12 months posttransplant is approximately 5.

The role of organic anion-transporting polypeptides and their common genetic variants in mycophenolic acid pharmacokinetics

The goal of this study was to determine the roles of the organic anion-transporting polypeptides (OATPs) OATP1A2, OATP1B1, and OATP1B3 and their genetic variants in the pharmacokinetics of the immunosuppressive drug mycophenolate mofetil (MMF). Using OATP-transfected human embryonic kidney (HEK) cells, we measured the uptake of mycophenolic acid (MPA) and its glucuronide (MPAG). MPAG, but not MPA, significantly accumulated in cells expressing OATP1B3 or OATP1B1 (P < 0.05). The pharmacokinetics of both MPA and MPAG were significantly influenced by the OATP1B3 polymorphism 334T>G/699G>A in 70 renal transplant patients receiving combination treatment of MMF with either tacrolimus or sirolimus, but not in 115 patients receiving MMF and cyclosporine. The decrease in dose-normalized (dn) MPA exposure and the concomitant increase in the MPAG/MPA metabolic ratio are consistent with reduced enterohepatic cycling in patients carrying the OATP1B3 334G-699A haplotype. Further studies demonstrated that this variant of OATP1B3 exhibited a reduced maximal velocity (V(max)) in transfected HEK cells, thereby providing functional evidence to support our clinical findings.

Interstitial fibrosis quantification in renal transplant recipients randomized to continue cyclosporine or convert to sirolimus

Conversion from cyclosporine (CsA) to sirolimus at week 12 after kidney transplantation is associated with a significant improvement in renal function. The aim of this analysis was to investigate the effect of this conversion on interstitial fibrosis (IF), a hallmark of chronic allograft injury, in patients taking part in the CONCEPT trial. This multicenter, prospective, trial included 193 renal recipients randomized at week 12 to switch from CsA to sirolimus or to continue CsA, with mycophenolate mofetil. Routine biopsy with automated, quantified assessment of IF by a program of color segmentation was performed at 1 year in 121 patients. At 1 year, renal function was significantly improved in the conversion group as assessed by estimated GFR (MDRD) and measured GFR. Biopsy results, however, showed no between-group difference in percentage of IF. Calculated GFR at 1 year was significantly associated with the percentage of IF (p = 0.004, R(2)= 0.07). By multivariate analysis diabetic patients had more fibrosis than non-diabetic patients. In conclusion, although kidney transplant patients converted from CsA to sirolimus showed significant improvement in renal function, we found no difference of IF on 1-year biopsies.

Induction of porcine regulatory cells by mycophenolic Acid-treated dendritic cells

Tolerance induction in murine allogeneic transplantation is relatively easy, often by induction of regulatory T cells (Treg). Unfortunately, the implementation of these models in clinical situations has not yielded reliable protocols of tolerance induction in humans. Our project sought to create a preclinical model of tolerance induction in large animals. Our current efforts seek to induce and characterize porcine Treg, obtaining dendritic cells (DC) able to preferentially stimulate them. DCs were differentiated from blood monocytes with porcine recombinant interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) for 6 days. These DCs were then stimulated by human CD40 ligand-transfected L cells with or without mycophenolic acid (MPA) for 48 hours. We analyzed surface marker expression, cytokine synthesis, and ability to stimulate allogeneic peripheral blood mononuclear cells (PBMC). The porcine lymphocytes underwent 4 rounds of 1-week stimulation with allogeneic DC treated or not with MPA. At the end of this coculture we analyzed their capacity to suppress allogeneic PBMC proliferation induced by mature DC. Our results showed that porcine DCs pretreated with MPA display a low expression of B7 costimulatory molecules, produce low levels of IL-12, and induce weak proliferation of allogeneic lymphocytes. Moreover, after 4 rounds of stimulation with MPA-treated DCs, PBMCs were able to inhibit an alloreactive response. These preliminary results suggested induction of a regulatory T-cell population that we are currently seeking to characterize.

Mycophenolate mofetil in patients with systemic lupus erythematosus: a prospective pharmacokinetic study

Few studies have assessed the pharmacokinetics of mycophenolic acid (MPA) in non-transplanted patients treated with mycophenolate mofetil (MMF), and little information is available concerning a concentration-effect relationship between the MPA area under the curve (AUC) and the immunological parameters in patients treated for systemic lupus erythematosus (SLE). We evaluated the variations in pharmacokinetics for MPA in patients with SLE and the relationship between MPA-AUC and markers of disease activity. MPA blood concentrations were measured through enzyme-multiplied immunotechnique (T(0), T(30'), T(1h), T(2h), T(3h) and T(4h)) to determine the MPA AUC(0-4h) in patients treated with MMF since at least 4 weeks for SLE. Clinical examination, biochemical analyses and immunological analyses were performed on the same day. The relationship between MPA exposure and disease activity markers was assessed. A total of 20 patients were included in the study. The diagnosis of SLE had been made 87 +/- 72 months before and patients had been treated with MMF for 31 +/- 30 months. Mean dose of MMF on the day of the study was 1600 +/- 447 mg/day. Mean MPA AUC(0-4h) was 28.4 +/- 13.6 mg h/L, mean dose-normalised AUC(0-4h) was 35.5 +/- 13.8 mg h/L and mean MPA C(0) was 3.1 +/- 2.2 mg/L. There was a high correlation between MPA AUC(0-4h) and MPA C(0), (r = 0.80; P < 0.001). AUC(0-4h) tended to be lower in patients who had low complement C3 concentration (<0.67 g/L) and low complement C4 concentration (<0.14 g/L). Moreover, there was a significant relationship between MPA trough levels and complement C4 concentrations (P = 0.043). We confirmed high inter-individual variability of MPA AUC in patients treated with MMF for SLE. This suggests that MPA exposure may be unpredictable with a fixed MMF dose. There was a concentration-effect relationship between MPA exposure (C(0)) and immunological disease activity parameters.

Efficacy on renal function of early conversion from cyclosporine to sirolimus 3 months after renal transplantation: concept study

Sirolimus (SRL) allows to minimize the use of cyclosporine (CsA), but de novo administration after transplantation is associated with various complications. We report a prospective, open-label, multicenter randomized study to evaluate conversion from a CsA-based regimen to a SRL-based regimen 3 months after transplantation. One hundred ninety-two of a total of 237 patients were eligible at 3 months to be converted to SRL (n = 95) or to continue CsA (n = 97). All patients were also given mycophenolate mofetil (MMF) and oral steroids, planned to be discontinued at month 8. The primary endpoint, the clearance estimated according to Cockcroft and Gault at week 52, was significantly better in the SRL group (68.9 vs. 64.4 mL/min, p = 0.017). Patient and graft survival were not statistically different. The incidence of acute rejection episodes, mainly occurring after withdrawal of steroids, was numerically but not statistically higher in the SRL group (17% vs. 8%, p = 0.071). Sixteen patients discontinued SRL, mainly for adverse events (n = 11), and seven patients discontinued CsA for renal failure or acute rejection. Significantly, more patients in the SRL group reported aphthous, diarrhea, acne and high triglyceride levels. Conversion CsA to SRL 3 months after transplantation combined with MMF is associated with improvement in renal function.

Predominant Th1 and cytotoxic phenotype in biopsies from renal transplant recipients with transplant glomerulopathy

Transplant glomerulopathy (TGP) appears to be a pathogenic feature of chronic antibody-mediated rejection, but the pathogenesis of this histologic entity is still poorly understood. Previous studies suggest the involvement of lymphocytes but the phenotypes of these cells have never been analyzed. Here, we report the first study of mRNAs for specific markers of CD4+ T cells including Th1 (T-bet and INFgamma), Th2 (IL4 and GATA3), Treg (Foxp3) and Th17 (IL-17 and RORgammat) subsets, cytotoxic CD8 T cells (Granzyme B) and B-cell markers (CD20) in renal biopsies from renal transplant recipients suffering interstitial fibrosis and tubular atrophy (IF/TA) with or without TGP but with a similar inflammatory score and controls including transplant recipients with normal renal function. Only INFgamma, T-bet (both functionally defined markers of Th1 CD4 T cells) and granzyme B (a CD8 cytotoxic marker) were significantly more strongly expressed in patients with TGP than in patients without TGP and normal controls. These results indicate a role of an active T-mediated inflammatory and cytotoxic process in the pathogenesis of TGP.

[IL-2/IL-2R pathway in dendritic cell modulates both their cytokine synthesis profiles and their capacity to activate allogeneic CD4+ T lymphocytes]

The results provide new insights into the role of IL-2/IL-2R pathway in DC. We report that stimulation of human monocyte-derived DC with LPS strongly upregulated CD25 (α chain of the IL-2R) expression. In addition, by using a humanized monoclonal antibody against CD25, we demonstrated that the IL-2 signalling in DC upregulated both IL-12 and γIFN production but decreased IL-10 synthesis. Anti-CD25 treatment reduced the ability of LPS-DC to induce allogeneic CD4(+) T cell proliferation as compared to LPS-matured DC. In addition, LPS-matured DC treated with IL-2 had a higher allostimulatory capacity compared to LPS-DC. We also found that LPS-matured DC produced IL-2. Thus, IL-2 seems to contribute actively to DC activation through an autocrine pathway. Moreover, IL-2 pathway in DC is involved in T helper priming. These findings might be useful for protocols in cellular therapy and a valuable tool to understand graft rejection versus the acquisition of peripheral tolerance.

New approaches to de novo immunosuppression and steroid elimination

Calcineurin inhibitors (CNIs) and steroids, the cornerstones of most immunosuppressive regimens over the past 20 years, have undesirable chronic side effects, leading to the application of new strategies with sirolimus (SRL) and mycophenolate mofetil (MMF). We evaluated de novo CNI avoidance and early steroid withdrawal among 145 renal recipients randomized to receive either SRL (n = 71) or cyclosporine (CsA; n = 74). All patients received polyclonal antithymocyte globulin (ATG) for 5 days, MMF, and steroid withdrawal at 6 months (SPIESSER study). At 12 months, patient and graft survivals, incidence of biopsy-proven acute rejection (BPAR), and rates of steroid withdrawal were not statistically different namely, 97% versus 97%; 90% versus 93%, 14.3% versus 8.6%, and 82.8% versus 84.1%, respectively. Among patients who remained on treatment according to the protocol, the estimated glomerular filtration rate (eGFR) was significantly higher with SRL (69 +/- 19 versus 60 +/- 14 mL/min; P < .01). In another study of delayed introduction of SRL, 192 renal recipients were prospectively randomized at week 12 to switch from CsA to SRL (n = 95) or to continue CsA (n = 97; CONCEPT study). At 12 months, patient and graft survivals of the randomized patients, incidence of BPAR, and rates of steroid withdrawal were not significantly different: 100% versus 100%, 100% versus 98%, 17% versus 8%, and 72% versus 78%, respectively. Upon ITT eGFR was significantly higher with SRL (68.9 vs 64.4 mL/min; P = .017). In both studies, a significant improvement in renal function was observed at 12 months among patients receiving a maintenance regimen with SRL plus MMF. Furthermore, steroids could be withdrawn in three quarters of the patients.

Mycophenolic Acid Inhibits p38 Mitogen-Activated Protein Kinase in Human Monocyte-Derived Dendritic Cells Stimulated by Lipopolysaccharide

Dendritic cell (DC) maturation, a crucial stage in the immune response, can be induced by various stimuli, such as lipopolysaccharide (LPS). Maturation signals trigger up-regulation of costimulatory molecule expression, increasing the ability of DCs to prime T helper cells. We and others have previously reported that mycophenolic acid (MPA) inhibits DC maturation and activation. However, the mechanisms remain unknown. The primary effect of MPA is inhibition of inosine monophosphate dehydrogenase (IMPDH), an enzyme involved in the de novo synthesis of guanosine nucleotide. The process of DC maturation is highly dependent on mitogen-activated protein kinase (MAPK) phosphorylation, especially p38MAPK. We therefore decided to study whether MPA affects these processes. Human monocyte-derived DCs were activated by LPS in the presence or absence of MPA. To assess whether the depletion of guanine affected p38MAPK phosphorylation, increasing doses of exogenous guanosine were added before stimulation. The results by flow cytometry showed that MPA inhibited p38MAPK phosphorylation by 25%. Interestingly, exogenous guanosine did not reverse the MPA inhibition. Our results suggested that MPA inhibits p38MAPK activity independent of IMPDH in human DCs. This effect of MPA may explain its capacity to inhibit maturation marker expression on DCs.

Anti-CD25 antibodies decrease the ability of human dendritic cells to prime allogeneic CD4 T cells

Anti-CD25 monoclonal antibodies are largely used in clinical transplantation to prevent acute allograft rejection episodes. Although their effects on T lymphocytes have been extensively studied, their impact on human dendritic cells (DCs) has been less reported. Furthermore, the role of the interleukin-2 in DC functions has not yet been fully elucidated. In this study, we observed that stimulation of human monocyte-derived DCs with lipopolysa ccharide or CD40L strongly induced the expression of CD25. We showed that pretreatment of DC with anti-CD25 diminished their ability to prime T-helper cells. In contrast, humanized anti-CD25 monoclonal antibodies did not affect the up-regulation of CD86, CD80, CD83, HLA-DR, or CD40 induced by lipopolysaccharide stimulation. This study supported previously unrecognized effects of anti-CD25 monoclonal antibodies on DCs that may contribute to their clinical efficacy.

Early pulse pressure and low-grade proteinuria as independent long-term risk factors for new-onset diabetes mellitus after kidney transplantation

Risk factors for new-onset diabetes after transplantation (NODAT) need to be assessed in large cohorts. We retrospectively evaluated the impact of early (3 and 6 months after transplantation) proteinuria, urinary albumin excretion (UAE) and arterial pressure on NODAT in 828 Caucasian renal transplant recipients (median follow-up: 5.3 years; 5832 patient-years). The 10- and 20-year incidence of NODAT was 15.0% and 22.0%, respectively. Low-grade (<1 g/day) (HR: 2.04 [1.25-3.33], p = 0.0042) and very low-grade (<0.3 g/day) (HR: 2.21 [1.32-3.70], p = 0.0025) proteinuria were independent risk factors for NODAT. There was a dose-dependent relationship across UAE categories (increasing risk from normoalbuminuria to macroalbuminuria) with NODAT. Tacrolimus, sirolimus and beta-blockers (HR: 1.86 [1.07-3.22], p = 0.0277) were significantly associated with NODAT even after multiple adjustments, but not diuretics, angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers. Systolic arterial pressure (HR per 10 mmHg: 1.16 [1.03-1.29], p = 0.0126) and pulse pressure (HR: 1.26 [1.12-1.43], p = 0.0002) were associated with NODAT. Only pulse pressure remained significant after adjustments. Patients at highest risks had early proteinuria and pulse pressure >60 mmHg. Early low-grade proteinuria and pulse pressure (in addition to beta-blockers) constitute independent risk factors for NODAT; they may be markers of the metabolic syndrome and/or vascular damage in renal transplant recipients.

Anti-CD25 antibodies affect cytokine synthesis pattern of human dendritic cells and decrease their ability to prime allogeneic CD4+ T cells

Anti-CD25 monoclonal antibodies are widely used in clinical transplantation to prevent acute allograft rejection. Although their effects on T lymphocytes have been extensively studied, their impact on human dendritic cells (DC) has never been reported. Furthermore, the role of the IL-2 in DC functions has not yet been fully elucidated. In this study, we confirm that the stimulation of human monocyte-derived DC with LPS strongly induced the expression of CD25 and that LPS-matured DC also expressed the beta and gamma chain of the IL-2R. We also showed that adding anti-CD25 monoclonal antibodies to LPS induced a decrease in IL-12, IL-1, TNF-alpha, IL-6, and IFN-gamma production and an increase in IL-10 synthesis by DC compared with stimulation with LPS alone. Furthermore, we showed that these modifications diminished the T helper priming ability of DC and polarized the alloimmune response toward TH2. In contrast, humanized anti-CD25 monoclonal antibodies did not affect the up-regulation of CD86, CD80, CD83, HLADR, or CD40 induced upon LPS stimulation. Taken together, this study discloses some previously unrecognized effects of anti-CD25 monoclonal antibodies on DC that may contribute to their clinical efficacy. In addition, this study also shed some light on the role of the IL-2 in human DC activation.

Disappearance of tophi in familial juvenile hyperuricemic nephropathy after kidney transplantation

A 40-year-old man who had been on hemodialysis for 25 months due to familial juvenile hyperuricemic nephropathy (FJHN) received a kidney transplant. Biopsy of his native kidney had shown tubulo-interstitial nephropathy. Genetic analysis confirmed abnormal uromodulin expression due to a mutation in the exon 4 of the UMOD gene. He had multiple tophi on the day of transplantation, including some on his fingers. He received immunosuppressive treatment including polyclonal antilymphocyte antibodies, mycophenolate mofetil, steroids and cyclosporine and achieved excellent renal function, with serum creatinine at 13 mg/L on day 10 posttransplantation and 9.4 mg/L at 6 months. His uric acid excretion rate increased from 4.4% at day 2 posttransplantation to 7.7% 6 months after transplantation. The number and sizes of the tophi were reduced 3 months posttransplantation, and nearly disappeared at month 6. Serum uric acid level decreased slowly from 650 mumol/L before transplantation to 300 mumol/L. Reduction of tophi was probably due to the absence of the mutated UMOD gene in the transplanted kidney.

Sirolimus versus cyclosporine in kidney recipients receiving thymoglobulin, mycophenolate mofetil and a 6-month course of steroids

To evaluate the efficacy and tolerance of a calcineurin inhibitor (CNI)-free regimen, 145 renal recipients were prospectively randomized to receive either sirolimus (n = 71) or cyclosporine (CsA; n = 74). All patients received polyclonal antilymphocyte antibodies, mycophenolate mofetil (MMF) and steroids (6 months). The primary endpoint, estimated glomerular filtration rate (eGFR) was not significantly different at 12 months comparing sirolimus- and CsA-treated patients (60 +/- 27 vs. 57 +/- 21 mL/min). At 12 months, patient and graft survival, incidence of biopsy-proven rejection and rates of steroid withdrawal were not statistically different (97% vs. 97%; 90% vs. 93%; 14.3% vs. 8.6% and 82.8% vs. 84.1%, respectively). Delayed and slow graft function (SGF) was not significantly different (18.6% vs. 12.3% and 11.4% vs. 13.7%, respectively). In patients who remained on treatment according to protocol at 12 months, eGFR was significantly higher with sirolimus (69 +/- 19 vs. 60 +/- 14 mL/min, p = 0.01). Overall study drug discontinuation rates were 28.2% with sirolimus and 14.9% with CsA. Adverse events (wound complications, mouth ulcers, diarrhea, hypokalemia, bronchopneumonia) and proteinuria >0.5 g/24h (38.8% vs. 5.6%, p < 0.001) were significantly more frequent in sirolimus-treated patients. Cytomegalovirus (CMV) infections were significantly less frequent with sirolimus (6% vs. 23%, p < 0.01). A CNI-free regimen using sirolimus-MMF can achieve excellent renal function, but patients on sirolimus experienced a high rate of adverse events and study drug discontinuation.

Sirolimus versus cyclosporine in kidney recipients receiving thymoglobulin, mycophenolate mofetil and a 6-month course of steroids

To evaluate the efficacy and tolerance of a calcineurin inhibitor (CNI)-free regimen, 145 renal recipients were prospectively randomized to receive either sirolimus (n = 71) or cyclosporine (CsA; n = 74). All patients received polyclonal antilymphocyte antibodies, mycophenolate mofetil (MMF) and steroids (6 months). The primary endpoint, estimated glomerular filtration rate (eGFR) was not significantly different at 12 months comparing sirolimus- and CsA-treated patients (60 +/- 27 vs. 57 +/- 21 mL/min). At 12 months, patient and graft survival, incidence of biopsy-proven rejection and rates of steroid withdrawal were not statistically different (97% vs. 97%; 90% vs. 93%; 14.3% vs. 8.6% and 82.8% vs. 84.1%, respectively). Delayed and slow graft function (SGF) was not significantly different (18.6% vs. 12.3% and 11.4% vs. 13.7%, respectively). In patients who remained on treatment according to protocol at 12 months, eGFR was significantly higher with sirolimus (69 +/- 19 vs. 60 +/- 14 mL/min, p = 0.01). Overall study drug discontinuation rates were 28.2% with sirolimus and 14.9% with CsA. Adverse events (wound complications, mouth ulcers, diarrhea, hypokalemia, bronchopneumonia) and proteinuria >0.5 g/24h (38.8% vs. 5.6%, p < 0.001) were significantly more frequent in sirolimus-treated patients. Cytomegalovirus (CMV) infections were significantly less frequent with sirolimus (6% vs. 23%, p < 0.01). A CNI-free regimen using sirolimus-MMF can achieve excellent renal function, but patients on sirolimus experienced a high rate of adverse events and study drug discontinuation.

Urinary albumin excretion and the risk of graft loss and death in proteinuric and non-proteinuric renal transplant recipients

BACKGROUND

Microalbuminuria and macroalbuminuria constitute risk factors for ESRD and death in non-transplanted populations. Whether microalbuminuria (especially in non-proteinuric patients) and macroalbuminuria constitute risk factors for graft loss and death is presently unknown in renal transplantation.

METHODS

We retrospectively assessed the association between urinary albumin excretion (UAE) and ESRD and death in renal transplantation.

RESULTS

UAE was measured in 616 (397 proteinuric; 219 non-proteinuric patients) renal transplant recipients. They were grafted for 62 months (range: 6-192). During the 40 months (3.7-99) thereafter, 31 patients underwent dialysis and 32 died. Microalbuminuria (vs. normoalbuminuria) and macroalbuminuria (vs. microalbuminuria) were powerful risk factors for graft loss [OR: 14.25 (2.88-52.3) and 16.41 (7.46-36.0), respectively, both p < 0.0001], even after adjustments on renal function and diabetes. Among the 219 non-proteinuric patients, microalbuminuria (vs. normoalbuminuria) was a significant risk factor for graft loss [OR: 23.09 (1.93-276.4), p = 0.0132]. Both microalbuminuria (vs. normoalbuminuria) [OR: 5.55 (2.43-12.66), p < 0.0001] and macroalbuminuria (vs. microalbuminuria) [OR: 4.12 (1.65-10.29), p = 0.0024] were predictive of death.

CONCLUSIONS

Microalbuminuria and macroalbuminuria are powerful independent predictors of ESRD and death. Microalbuminuria is a risk factor for graft loss even in non-proteinuric patients. UAE provides additional information on renal and patient prognosis as compared to proteinuria and renal function.

Tolerability of enteric-coated mycophenolate sodium to 1 year in combination with cyclosporine and corticosteroids in renal transplant recipients

Enteric-coated mycophenolate sodium (EC-MPS) is therapeutically equivalent to mycophenolate mofetil, but delays release of mycophenolic acid until it reaches the small intestine. De novo renal transplant patients taking part in a 12-month, multicenter, randomized study received cyclosporine microemulsion (CsA-ME, early or delayed to day 6), EC-MPS, steroids, and interleukin-2 antagonist induction. Tolerability data relating to EC-MPS are reported. Ninety-seven patients were randomized to early CsA-ME and 100 patients to delayed CsA-ME. Median daily dose of EC-MPS was 1440 mg at all time points throughout the 12-month period. The most frequently reported adverse events were constipation, anemia, urinary tract infection, abdominal pain, leukopenia, and cytomegalovirus infection; there were four malignancies. Fifty patients (24.6%) discontinued EC-MPS prematurely by 12 months, including 42 patients (84%) who discontinued owing to adverse events. No patient discontinued treatment because of gastrointestinal adverse events. Two-thirds of patients (137 [67.5%]) maintained full EC-MPS dose throughout the 12-month study and did not require any dose reduction or dose interruption. EC-MPS is well tolerated in de novo renal transplant recipients when administered in combination with CsA-ME and steroids, with low rates of dose reductions or interruptions. Gastrointestinal adverse events were responsible for dose reduction or interruption in only 5% of patients.

Urinary albumin excretion and the risk of graft loss and death in proteinuric and non-proteinuric renal transplant recipients

BACKGROUND

Microalbuminuria and macroalbuminuria constitute risk factors for ESRD and death in non-transplanted populations. Whether microalbuminuria (especially in non-proteinuric patients) and macroalbuminuria constitute risk factors for graft loss and death is presently unknown in renal transplantation.

METHODS

We retrospectively assessed the association between urinary albumin excretion (UAE) and ESRD and death in renal transplantation.

RESULTS

UAE was measured in 616 (397 proteinuric; 219 non-proteinuric patients) renal transplant recipients. They were grafted for 62 months (range: 6-192). During the 40 months (3.7-99) thereafter, 31 patients underwent dialysis and 32 died. Microalbuminuria (vs. normoalbuminuria) and macroalbuminuria (vs. microalbuminuria) were powerful risk factors for graft loss [OR: 14.25 (2.88-52.3) and 16.41 (7.46-36.0), respectively, both p < 0.0001], even after adjustments on renal function and diabetes. Among the 219 non-proteinuric patients, microalbuminuria (vs. normoalbuminuria) was a significant risk factor for graft loss [OR: 23.09 (1.93-276.4), p = 0.0132]. Both microalbuminuria (vs. normoalbuminuria) [OR: 5.55 (2.43-12.66), p < 0.0001] and macroalbuminuria (vs. microalbuminuria) [OR: 4.12 (1.65-10.29), p = 0.0024] were predictive of death.

CONCLUSIONS

Microalbuminuria and macroalbuminuria are powerful independent predictors of ESRD and death. Microalbuminuria is a risk factor for graft loss even in non-proteinuric patients. UAE provides additional information on renal and patient prognosis as compared to proteinuria and renal function.

Long-term results of monoclonal anti-Il2-receptor antibody versus polyclonal antilymphocyte antibodies as induction therapy in renal transplantation

We compared the influence of induction therapy on 5-year patient and graft survival as well as on renal function in 100 kidney graft recipients at low immunological risk treated with antilymphocyte globulin (n = 50) versus anti-IL-2R monoclonal antibody (n = 50) in a prospective multicenter study. Long-term immunosuppressive treatment included cyclosporine, mycophenolate mofetil, and a short course of steroids in all patients. Five year graft (86% vs 86%) and patient (94% vs 94%) survivals were identical in both study arms. Moreover, neither serum creatinine or proteinuria were significantly different between the two groups. Our results showed that the choice of the induction therapy seemed to not have a major impact on long-term outcomes among renal recipients at low immunological risk.

Early Proteinuria Is a Strong Indicator of Donor Renal Lesions, Ischemia-Reperfusion Injury and Immunological Aggression

BACKGROUND

Early proteinuria is associated with reduced long-term graft survival. However, the determinants and mechanisms of proteinuria early after transplantation have not been identified.

METHODS

Parameters associated with proteinuria within the first 3 months following transplantation were retrospectively assessed among 484 renal transplant recipients.

RESULTS

Proteinuria was more abundant in patients with a history of two or more rejection episodes (0.42 +/- 0.68 vs 0.18 +/- 0.39 g/d; P = .02). Proteinuria was greater when donor age was 60 or more (OR: 4.43; P = .003), when recipient death was due to cardiovascular causes (OR: 1.98; P = .002), or when cold (OR: 1.77; P = .006) or warm (1.21; P = .09) ischemia times were prolonged.

CONCLUSIONS

Proteinuria early after transplantation was related to pretransplant renal lesions, ischemia-reperfusion, and immunologic injuries.

Estimation of the Glomerular Filtration Rate Through Different Methods in Kidney Transplant Recipients: Correlation With the Creatinine Clearance Measurement

The measurement of the glomerular filtration rate (GFR) is an important tool for physicians to follow kidney transplant recipients. Indeed, renal function has been shown to be predictive of graft outcome in retrospective studies. Several methods have been proposed to measure GFR. In the present study we evaluated the correlation of GFR between a reference method (calculation through the urine to plasma ratio of creatinine [UV/P] formula) and three estimation equations (Cockcroft and Gault; Nankivell; modification of diet in renal disease) in 81 kidney transplant recipients at 3 and 12 months posttransplantation. We showed a significant correlation between the three predictive formulas and UV/P, but none of the predictive equations showed an excellent correlation. The best correlation between an estimation equation and the UV/P formula was the CG formula. Further studies are required to compare the estimated GFR with better reference methods, such as the use of isotopic markers in kidney graft recipients.

Low 1-Year Cyclosporine Microemulsion Doses Are Associated With Better 5-Year Renal Graft Function: An Insight From MOST, a Multinational Observational Study

BACKGROUND

In earlier registry analyses, cyclosporine at doses of < 3 mg/kg/d at 1 year post-renal transplantation has been associated with significant graft loss or reduction in renal function. Improvements in cyclosporine formulation with increased bioavailability, plus the use of more efficient comedications, may now confer better outcomes. To determine the effect of the 1-year cyclosporine microemulsion (CsA-ME) dose on renal allograft function at 5 years, we analyzed data collected from 2889 patients with documented graft survival to year 5 in a prospective, multinational, observational study-Neoral MOST.

RESULTS

Glomerular filtration rate (GFR) at year 1 was 63 +/- 20 mL/min and 59 +/- 22 mL/min at year 5. The multivariate analysis including year 1 CsA-ME dose as factor and GFR at 1 year as covariate revealed the most significant factors affecting GFR at year 5 were 1-year GFR, donor age > 60 years, and CsA-ME dose at 1 year. Risk factors associated with reduction in 5-year GFR (<65 mL/min) included donor or recipient age >60 years, delayed graft function, cadaveric donor, previous graft, and acute rejection. CsA-ME dose <3 mg/kg/d was found to protect GFR. Analysis of GFR at each year posttransplantation (Wilcoxon model) found 1-year CsA-ME (cutoff 3 mg/kg/d) had a significant effect at each time point.

CONCLUSIONS

Compared to higher doses, CsA-ME <3 mg/kg/d at year 1 posttransplantation is associated with increased preservation of renal allograft function at year 5.

Renal artery aneurysm secondary to Candida albicans in four kidney allograft recipients

INTRODUCTION

Infection is a frequent cause of morbidity and mortality in solid organ transplant recipients. It may occur at different periods after transplantation. We report four cases of mycotic aneurysms due to Candida albicans (CA) in renal transplant recipients occurring early after kidney transplantation.

CASE REPORTS

Four patients (three men, one woman) aged from 24 to 55 years who underwent cadaveric renal transplantation from three different donors developed a mycotic aneurysm at 9 to 90 days after transplantation. In all cases aneurysms were located at the anastomosis between the renal graft artery and the iliac axis. The clinical presentations were fever in three cases, including endocarditis in one patient or deterioration of graft function in two cases and hemorrhagic shock secondary to a ruptured renal artery in the fourth case, which led to death. The arterial aneurysm was discovered at autopsy. The diagnosis of a mycotic aneurysm was based on morphological investigations: echotomography, spiral computed tomography, and arteriography. In all cases bacteriological studies (blood culture, culture of the aneurysmal wall and content) isolated CA. In three patients CA was isolated from the preservation solution; it was of the same phenotype as the one isolated from the aneurysm in one recipient. Antifungal therapy was started in patients who lived, but all kidney transplants had to be removed. Anatomical results of arterial reconstructions were satisfactory in all cases and remained so during the follow-up.

CONCLUSION

The insidious presentation and clinical course of mycotic aneurysms due to CA require a high degree of suspicion to make the correct diagnosis.

Delayed graft function: risk factors, consequences and parameters affecting outcome-results from MOST, A Multinational Observational Study

BACKGROUND

Delayed graft function (DGF) is a common complication after renal transplantation, and may affect graft function. The aim of this analysis was to evaluate risk factors for DGF, as well as parameters and events influencing graft function after DGF. We analyzed data collected in an ongoing international, prospective; observational study, the Neoral-MOST (Multinational Observational Study in renal Transplantation), and included in the analysis all patients with cadaveric kidney transplants for whom renal function at 1 year posttransplantation was documented (N = 8950). Logistic regression was used to evaluate the risk factors for DGF occurrence, and multifactorial analysis of variance (ANCOVA) to assess the relevance of different factors for GFR at 1 year.

RESULTS

Higher donor age, longer CIT, male recipients, Caucasian recipients, high recipients body mass index, and PRA were all associated with a higher risk for DGF. Renal function of former DGF kidneys at 1 year was lower in kidneys of elder donors, or which had experienced rejection or CMV infection. Variations of the maintenance regimen at 1 year posttransplantation were not associated with better graft function. Multifactorial analysis showed donor age and acute rejection as significant independent factors.

CONCLUSIONS

Most factors increasing the risk for DGF or having a negative impact on renal function at 1 year in grafts with DGF are predetermined. Additional posttransplant damage by acute rejection was associated with further reductions in GFR. Preventing acute rejection is an important step in achieving optimal function of DGF grafts.