Rationale and design of the OPTIMIZE trial: OPen label multicenter randomized trial comparing standard IMmunosuppression with tacrolimus and mycophenolate mofetil with a low exposure tacrolimus regimen In combination with everolimus in de novo renal transplantation in Elderly patients.

BACKGROUND: In 2019, more than 30 % of all newly transplanted kidney transplant recipients in The Netherlands were above 65 years of age. Elderly patients are less prone to rejection, and death censored graft loss is less frequent compared to younger recipients. Elderly recipients do have increased rates of malignancy and infection-related mortality. Poor kidney transplant function in elderly recipients may be related to both pre-existing (i.e. donor-derived) kidney damage and increased susceptibility to nephrotoxicity of calcineurin inhibitors (CNIs) in kidneys from older donors. Hence, it is pivotal to shift the focus from prevention of rejection to preservation of graft function and prevention of over-immunosuppression in the elderly. The OPTIMIZE study will test the hypothesis that reduced CNI exposure in combination with everolimus will lead to better kidney transplant function, a reduced incidence of complications and improved health-related quality of life for kidney transplant recipients aged 65 years and older, compared to standard immunosuppression. METHODS: This open label, randomized, multicenter clinical trial will include 374 elderly kidney transplant recipients (≥ 65 years) and consists of two strata. Stratum A includes elderly recipients of a kidney from an elderly deceased donor and stratum B includes elderly recipients of a kidney from a living donor or from a deceased donor < 65 years. In each stratum, subjects will be randomized to a standard, tacrolimus-based immunosuppressive regimen with mycophenolate mofetil and glucocorticoids or an adapted immunosuppressive regimen with reduced CNI exposure in combination with everolimus and glucocorticoids. The primary endpoint is 'successful transplantation', defined as survival with a functioning graft and an eGFR ≥ 30 ml/min per 1.73 m2 in stratum A and ≥ 45 ml/min per 1.73 m2 in stratum B, after 2 years, respectively. CONCLUSIONS: The OPTIMIZE study will help to determine the optimal immunosuppressive regimen after kidney transplantation for elderly patients and the cost-effectiveness of this regimen. It will also provide deeper insight into immunosenescence and both subjective and objective outcomes after kidney transplantation in elderly recipients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03797196 , registered January 9th, 2019. EudraCT: 2018-003194-10, registered March 19th, 2019.

Hyperhomocysteinemia: a trigger for complement-mediated TMA?

A 34-year-old man of North African descent was referred to the emergency department because of malignant hypertension (220/113 mmHg), acute visual disturbances and acute kidney failure (serum creatinine 14.0 mg/dL). Blood analysis was compatible with thrombotic microangiopathy (TMA). Kidney biopsy confirmed this diagnosis with histological changes including intimal edema, arteriolar thrombi, and severe tubulointerstitial damage. Fundoscopy showed hypertensive retinopathy stage IV. Subsequent biochemical screening revealed normal complement testing and a marked elevation in homocysteine concentration (161 µmol/L; normal value 7-15 µmol/L). Other secondary causes of TMA were excluded. Further genetic testing for cobalamin C (cblC) deficiency showed no pathogenic mutations in the MMACHC gene. However, a homozygous c.665C>T polymorphism (NM_005957.4) in the methylenetetrahydrofolate reductase (MTHFR) gene was found explaining the severe hyperhomocysteinemia due to reduced activity of MTHFR. Additional genetic testing for alternative complement pathway proteins showed mutations in the genes encoding factor H and factor B, both categorized as possibly pathogenic using mutation prediction software. This is the first described case of TMA in a patient with severe hyperhomocysteinemia caused by a genetic defect other than cblC. We postulate that endothelial damage due to hyperhomocysteinemia and hypertension could have triggered the TMA episode in this patient with two possible predisposing pathogenic mutations in the alternative complement pathway. Furthermore, our case demonstrates the need for complete full diagnostic testing in patients with TMA.

Disseminated histoplasmosis in a kidney liver transplant patient from a non-endemic area: A diagnostic challenge.

Disseminated histoplasmosis is a rare opportunistic infection in non-endemic areas, where the disease is often diagnosed late. The spectrum of clinical manifestations is broad and life-threatening complications occur. We present a detailed case of a kidney liver transplant patient with disseminated histoplasmosis in a non-endemic area. Our case highlights the wide range of pathogens to consider in the immunocompromised patient, the delayed diagnosis of Histoplasmosis Capsulatum in non-endemic areas and the possibility of severe gastrointestinal disease. We also briefly review diagnostic tests and treatment options.

Determinants of the Magnitude of Interaction Between Tacrolimus and Voriconazole/Posaconazole in Solid Organ Recipients.

Administration of azole antifungals to tacrolimus-treated solid organ recipients results in a major drug-drug interaction characterized by increased exposure to tacrolimus. The magnitude of this interaction is highly variable but cannot currently be predicted. We performed a retrospective analysis of 126 solid organ recipients (95 lung, 31 kidney) co-treated with tacrolimus and voriconazole (n = 100) or posaconazole (n = 26). Predictors of the change in tacrolimus dose-corrected trough concentrations (C/D) between baseline and tacrolimus-azole co-therapy were assessed using linear mixed modeling. Patients were genotyped for relevant polymorphisms in CYP3A4, CYP3A5, MDR1, CYP2C19, POR, and UGT1A4. Tacrolimus C/D increased by a factor 5.0 ± 2.7 (range 1.0-20.2) for voriconazole and 4.4 ± 2.6 (range 0.9-18.0) for posaconazole, suggesting that a 66% dose reduction is insufficient for the majority of patients. Change in C/D was blunted in CYP3A5 expressors (estimated effect: -43%, p = 0.017) and affected by hematocrit (+8% per %, p = 0.004), baseline C/D (-14% per 100% increase, p < 0.001), and age (+1%, p = 0.008). However, the final model explained only 22% of interindividual variability in C/D change. In conclusion, CYP3A5 genotype and several clinical variables were identified as modulators of the tacrolimus-azole interaction, but these did not permit accurate predictions in individual patients.

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.

Effect of ABCB1 diplotype on tacrolimus disposition in renal recipients depends on CYP3A5 and CYP3A4 genotype.

The relevance of most genetic polymorphisms beyond CYP3A5*1 on tacrolimus disposition remains unclear. We constructed a predictive mixed model for tacrolimus dose-corrected trough concentration (C0/dose) at months 3, 12 and 24 after transplantation in a retrospective cohort of 766 predominantly Causasian adult renal recipients (n=2042 trough concentrations). All patients were genotyped for 32 single-nucleotide polymorphisms with a proven or possible relevance to tacrolimus disposition based on the previous studies. Of these, ABCB1, ABCC2, OATP1B1, COMT, FMO, PPARA and APOA5 were analyzed as (functional) diplotype groups. Predictors of C0/dose were CYP3A5*1, hematocrit, age, CYP3A4*22, use of concomitant CYP3A4 inhibitor or inducer, ALT, estimated glomerular filtration rate, tacrolimus formulation (once vs twice daily), ABCB1 diplotype and time after transplantation. The effect of ABCB1 diplotype was small but strongly accentuated in CYP3A4*22 carriers and non-existent in CYP3A5 expressors. ABCC2 diplotype had a limited effect on C0/dose that was only statistically significant in CYP3A5 non-expressors.

Long-Term Outcomes in Belatacept- Versus Cyclosporine-Treated Recipients of Extended Criteria Donor Kidneys: Final Results From BENEFIT-EXT, a Phase III Randomized Study.

In the Belatacept Evaluation of Nephroprotection and Efficacy as First-Line Immunosuppression Trial-Extended Criteria Donors (BENEFIT-EXT), extended criteria donor kidney recipients were randomized to receive belatacept-based (more intense [MI] or less intense [LI]) or cyclosporine-based immunosuppression. In prior analyses, belatacept was associated with significantly better renal function compared with cyclosporine. In this prospective analysis of the intent-to-treat population, efficacy and safety were compared across regimens at 7 years after transplant. Overall, 128 of 184 belatacept MI-treated, 138 of 175 belatacept LI-treated and 108 of 184 cyclosporine-treated patients contributed data to these analyses. Hazard ratios (HRs) comparing time to death or graft loss were 0.915 (95% confidence interval [CI] 0.625-1.339; p = 0.65) for belatacept MI versus cyclosporine and 0.927 (95% CI 0.634-1.356; p = 0.70) for belatacept LI versus cyclosporine. Mean estimated GFR (eGFR) plus or minus standard error at 7 years was 53.9 ± 1.9, 54.2 ± 1.9, and 35.3 ± 2.0 mL/min per 1.73 m2 for belatacept MI, belatacept LI and cyclosporine, respectively (p < 0.001 for overall treatment effect). HRs comparing freedom from death, graft loss or eGFR <20 mL/min per 1.73 m2 were 0.754 (95% CI 0.536-1.061; p = 0.10) for belatacept MI versus cyclosporine and 0.706 (95% CI 0.499-0.998; p = 0.05) for belatacept LI versus cyclosporine. Acute rejection rates and safety profiles of belatacept- and cyclosporine-based treatment were similar. De novo donor-specific antibody incidence was lower for belatacept (p ≤ 0.0001). Relative to cyclosporine, belatacept was associated with similar death and graft loss and improved renal function at 7 years after transplant and had a safety profile consistent with previous reports.

High Intrapatient Variability of Tacrolimus Concentrations Predicts Accelerated Progression of Chronic Histologic Lesions in Renal Recipients.

High intrapatient variability (IPV) of tacrolimus concentrations is increasingly recognized as a predictor of poor outcome in solid organ recipients. How it relates to evolution of histology has not been explored. We analyzed tacrolimus IPV using the coefficient of variability (CV) from months 6-12 after transplantation in a cohort of 220 renal recipients for whom paired protocol biopsies at 3 mo and 2 years were available. Recipients in the highest CV tertile had an increased risk of moderate to severe fibrosis and tubular atrophy by 2 years compared with the low-IPV tertile (odds ratio [OR] 2.47, 95% confidence interval [CI] 1.09-5.60, p = 0.031; and OR 2.40, 95% CI 1.03-5.60, p = 0.043, respectively). Other predictors were donor age, severity of chronic lesions at 3 mo, and presence of borderline or subclinical rejection at 3 mo. Chronicity score increased significantly more in the high CV tertile group than in the middle and low tertiles (mean increase 1.97 ± 2.03 vs. 1.18 ± 2.44 and 1.12 ± 1.80, respectively; p < 0.05). CV did not predict evolution of renal function, which did not deteriorate within the 2-year follow-up period. These results indicate that high IPV is related to accelerated progression of chronic histologic lesions before any evidence of renal dysfunction.

Mycobacterium genavense infection in a solid organ recipient: a diagnostic and therapeutic challenge.

Renal transplant recipients are highly susceptible to infections caused by uncommon pathogens because of their immunocompromised state. We report a case of disseminated Mycobacterium genavense infection in a patient with a combined renal and cardiac transplant. Diagnosing M. genavense infections remains a challenge because of the absence of specific clinical symptoms in combination with the difficulties of culturing the organism using standard mycobacterial culture procedures. This clinical case demonstrates the importance of molecular techniques as part of the initial work-up in order to rapidly establish the diagnosis.

The effect of anastomosis time on outcome in recipients of kidneys donated after brain death: a cohort study.

Whether warm ischemia during the time to complete the vascular anastomoses determines renal allograft function has not been investigated systematically. We investigated the effect of anastomosis time on allograft outcome in 669 first, single kidney transplantations from brain-dead donors. Anastomosis time independently increased the risk of delayed graft function (odds ratio per minute [OR] 1.05, 95% confidence interval [CI] 1.02-1.07, p < 0.001) and independently impaired allograft function after transplantation (p = 0.009, mixed-models repeated-measures analysis). In a subgroup of transplant recipients, protocol-specified biopsies at 3 months (n = 186), 1 year (n = 189), and 2 years (n = 153) were blindly reviewed. Prolonged anastomosis time independently increased the risk of interstitial fibrosis and tubular atrophy on these protocol-specified biopsies posttransplant (p < 0.001, generalized linear models). In conclusion, prolonged anastomosis time is not only detrimental for renal allograft outcome immediately after transplantation, also longer-term allograft function and histology are affected by the duration of this warm ischemia.

Resolution of diffuse skin and systemic Kaposi's sarcoma in a renal transplant recipient after introduction of everolimus: a case report.

We present a case report of a patient with diffuse skin and systemic Kaposi's sarcoma (KS), 1 year after renal transplantation. A concomitant Pyrenochaeta romeroi granuloma of the right hallux was diagnosed and illustrated an important immunodysfunction in our patient. Four months after reduction in immunosuppression and switch to everolimus, a total regression of the KS was observed. Reduction in the immunosuppression and treatment with terbinafine cleared the P. romeroi infection, while lowering immunosuppression and changing the type of immunosuppressive therapy were important steps in the successful management of the KS. In recent years, evidence of the antitumor effects of everolimus is increasing: total regression of KS in combination with renal function preservation in renal graft recipients is possible with mammalian target of rapamycin (mTOR) inhibitor-based regimens. In addition, with increasing numbers of human immunodeficiency virus-positive transplant recipients, mTOR inhibitors may play a more crucial role in the management of KS.

The CYP3A4*22 C>T single nucleotide polymorphism is associated with reduced midazolam and tacrolimus clearance in stable renal allograft recipients.

Tacrolimus, a dual substrate of CYP3A4 and CYP3A5 has a narrow therapeutic index and is characterized by high between-subject variability in oral bioavailability. This study investigated the effects of the recently described CYP3A4*22 intron 6 C>T single nucleotide polymorphism on in vivo CYP3A4 activity as measured by midazolam (MDZ) clearance and tacrolimus pharmacokinetics in two cohorts of renal allograft recipients, taking into account the CYP3A5*1/*3 genotype and other determinants of drug disposition. In CYP3A5 non-expressers, the presence of one CYP3A4*22T-allele was associated with a 31.7-33.6% reduction in MDZ apparent oral clearance, reflecting reduced in vivo CYP3A4 activity. In addition, at ⩾12 months after transplantation, steady-state clearance of tacrolimus was 36.8% decreased compared with homozygous CYP3A4*22CC-wild type patients, leading to 50% lower dose requirements. Both concurrent observations in stable renal allograft recipients are consistent with a reduced in vivo CYP3A4 activity for the CYP3A4*22T-allele.

Hypotrichosis-lymphedema-telangiectasia-renal defect associated with a truncating mutation in the SOX18 gene.

SOX18 mutations in humans are associated with both recessive and dominant hypotrichosis-lymphedema-telangiectasia syndrome (HLTS). We report two families with affected children carrying a SOX18 mutation: a living patient and his stillborn brother from Canada and a Belgian patient. The two living patients were diagnosed with HLTS and DNA analysis for the SOX18 gene showed that both had the identical heterozygous C > A transversion, resulting in a pre-mature truncation of the protein, lacking the transactivation domain. Both living patients developed renal failure with severe hypertension in childhood for which both underwent renal transplantation. To our best knowledge this is the first report of renal failure associated with heterozygous mutations in the SOX18 gene. We conclude that this specific mutation results in a new, autosomal dominant condition and propose the acronym HLT-renal defect syndrome for HLTRS.

Effect of clinical examination and anatomical location on native arteriovenous fistula maturation rate in high risk patients.

BACKGROUND: Maximal use of native arteriovenous fistulas (AVFs) for patients on hemodialysis therapy remains a clinical challenge. Primary failure rates remain high with risk factors such as female gender, diabetes mellitus, lower arm AVF and higher age. We wondered if a strategy of careful clinical examination prior to AVF creation and a preference towards an upper arm AVF in case of doubt about the quality of the vein in patients with any of the above mentioned risk factors, would lead to better maturation rates. METHODS: The records of all patients who received an AVF between January 2005 and December 2009 at our University Hospitals Leuven were studied retrospectively. Demographic data, comorbidity, fistula characteristics, fistula maturation and fistula complications were recorded and analyzed. RESULTS: Of 344 patients enrolled, 156 (45.3%) received a lower arm AVF and 188 (54.7%) an upper arm AVF. Two hundred and seventy-six (80.2%) fistulas had a normal maturation. Lower arm AVF was a significant risk factor for non-maturation in this series (73.1% versus 86.2% ; p = 0,0024). Female gender, diabetes and high age were not, but female gender showed a significant difference in distribution in upper arm versus lower arm fistulas (62.40% versus 37.6% ; p = 0,0218). CONCLUSIONS: Careful clinical examination prior to upper or lower arm AVF creation together with the integration of risk assessment in the planning of AVF is worthwhile. A preference towards upper arm fistulas if major risk factors are -present can improve overall maturation rates and lead to the same maturation rates as in the overall dialysis population. Therefore, the presence of risk factors for non-maturation should not lead to the underuse of native AVFs.

Post-streptococcal glomerulonephritis: not an extinct disease!

We present the case of a 29-year-old type 1 diabetic patient with the diagnosis of acute post-streptococcal glomerulonephritis. The incidence of this textbook example of acute glomerulonephritis has dropped dramatically in the developed world during the past decades due to the more widespread use of antibiotics. However, the present case illustrates that it is not an extinct disease and that clinicians should be aware of this entity. Particular attention is needed for the fact that the clinical context in which the disease occurs may be different from the classical "post-angina" presentation.

Chronic wounds in a kidney transplant recipient with moderate renal impairment.

Calcific uremic arteriolopathy (CUA) or calciphylaxis is a condition predominantly observed in patients with end-stage kidney disease characterized by small vessel calcification, intimal proliferation, endovascular fibrosis and intravascular thrombosis causing down-stream infarction predominantly of skin resulting in extremely painful necrotic ulceration. Several interventions have been proposed in an attempt to attenuate the high mortality associated with CUA. One of the most promising therapeutic approaches is the administration of sodium thiosulfate which is able to chelate cations such as calcium and in this way possibly dissolving tissue calcium deposits into more hydrophilic calcium thiosulfate. Due to the scarcity of reports of CUA patients treated with sodium thiosulfate the safety profile of this drug is not (well) established at this moment especially in patients not receiving kidney replacement therapy. Here, we describe a case of a kidney transplant recipient with CUA and moderately declined kidney function who was treated with sodium thiosulfate and developed important hypernatremia and high anion gap acidosis necessitating significant reduction in dosing.

Combined kidney and intestinal transplantation in patients with enteric hyperoxaluria secondary to short bowel syndrome.

Kidney transplantation is the treatment of choice for end-stage renal disease whereas indications for intestinal transplantation are currently restricted to patients with irreversible small bowel failure and severe complications of total parenteral nutrition (mostly shortage and infection of venous accesses, major electrolyte disturbances and liver failure). Enteric hyperoxaluria is secondary to certain intestinal diseases like intestinal resections, chronic inflammatory bowel disease and other malabsorption syndromes and can lead to end-stage renal disease requiring kidney transplantation. We report two patients suffering from renal failure due to enteric hyperoxaluria (secondary to extensive intestinal resection) in whom we elected to replace not only the kidney but also the intestine to prevent recurrence of hyperoxaluria in the transplanted kidney.

Efficacy of sotrastaurin plus tacrolimus after de novo kidney transplantation: randomized, phase II trial results.

Sotrastaurin, a novel immunosuppressant, blocks early T cell activation through protein kinase C inhibition. Efficacy and safety of sotrastaurin with tacrolimus were assessed in a dose-ranging non-inferiority study in renal transplant recipients. A total of 298 patients were randomized 1:1:1:1 to receive sotrastaurin 100 (n = 77; discontinued in December 2011) or 200 mg (n = 73) b.i.d. plus standard tacrolimus (sTAC; 5-12 ng/mL), sotrastaurin 300 mg (n = 75) b.i.d. plus reduced tacrolimus (rTAC; 2-5 ng/mL) or enteric-coated mycophenolic acid (MPA) plus sTAC (n = 73); all patients received basiliximab and corticosteroids. Composite efficacy failure (treated biopsy-proven acute rejection ≥ grade IA, graft loss, death or loss to follow up) rates at Month 12 were 18.8%, 12.4%, 10.9% and 14.0% for the sotrastaurin 100, 200 and 300 mg, and MPA groups, respectively. The median estimated glomerular filtration rates were 55.7, 53.3, 64.9 and 59.2 mL/min, respectively. Mean heart rates were faster with higher sotrastaurin doses and discontinuations due to adverse events and gastrointestinal adverse events were more common. Fewer patients in the sotrastaurin groups experienced leukopenia than in the MPA group (1.3-5.5% vs. 16.5%). Sotrastaurin 200 and 300 mg had comparable efficacy to MPA in prevention of rejection with no significant difference in renal function between the groups.