The prevalence of osteopenia and osteoporosis after heart transplantation assessed using CT

OBJECTIVE

Osteoporosis is frequently observed in patients after heart transplantation (HT), although the prevalence long-term post-HT is unknown. Most studies investigating bone mineral density (BD) after HT were performed using dual-energy X-ray absorptiometry. In this study BD, including the prevalence of osteopenia and osteoporosis, was investigated using coronary computed tomography (CCT) long-term post-HT. Moreover, risk factors for abnormal BD were investigated.

METHODS

All first CCT scans between February 2018 and June 2020 used for the annual screening for cardiac allograft vasculopathy were included. Retransplantations and scans with not fully imaged vertebrae were excluded. BD was measured as a mean of the BD of three consecutive thoracic vertebrae and categorized into normal BD, osteopenia or osteoporosis. Binary logistic regression was used to find determinants for an abnormal BD. Linear regression was used to explore determinants for the mean Hounsfield unit (HU) value of the BD.

RESULTS

In total, 140 patients were included (median age 55.2 [42.9-64.9] years, 51 (36%) female). Time between HT and CT scan was 11.0 [7.3-16.1] years. In total, 80 (57%), 43 (31%), and 17 (12%) patients had a normal BD, osteopenia, or osteoporosis, respectively. Osteoporotic fracture or vertebrae fractures was seen in 11 (8%) patients. Determinants for an abnormal BD were recipient age (OR 1.10 (1.06-1.14), p<0.001) and prednisolone use (OR 3.75 (1.27-11.01), p=0.016). In linear regression, left ventricular assist device use pre-HT (p=0.024) and time since HT (p=0.046) were additional BD determinants.

DISCUSSION

Osteopenia and osteoporosis are frequently seen on CCT post-HT. More investigation on appropriate measures to maintain a normal BD in these patients are needed.

The mast cell: A Janus in kidney transplants

Mast cells (MCs) are innate immune cells with a versatile set of functionalities, enabling them to orchestrate immune responses in various ways. Aside from their known role in allergy, they also partake in both allograft tolerance and rejection through interaction with regulatory T cells, effector T cells, B cells and degranulation of cytokines and other mediators. MC mediators have both pro- and anti-inflammatory actions, but overall lean towards pro-fibrotic pathways. Paradoxically, they are also seen as having potential protective effects in tissue remodeling post-injury. This manuscript elaborates on current knowledge of the functional diversity of mast cells in kidney transplants, combining theory and practice into a MC model stipulating both protective and harmful capabilities in the kidney transplant setting.

Corrigendum: The mast cell: A Janus in kidney transplants

[This corrects the article DOI: 10.3389/fimmu.2023.1122409.].

Resistant hypertension improved after 3 months by measuring drug levels to identify non-adherence

Introduction

Identification of non-adherence to antihypertensive drugs is crucial to improve resistant hypertension (RH). For this therapeutic drug monitoring is the most reliable method.

Purpose

The primary objective of this analysis is to determine whether drug levels measured with a dried blood spot (DBS) method combined with personalized feedback leads to a decrease in prevalence of RH after 3 months due to an increase in adherence.

Methods

This is a multi-centre single-blinded randomized controlled trial (RHYME-RCT, NL6736). Patients went to an eligibility visit, where DBS sampling and a 24-hour ambulatory blood pressure measurement (ABPM) was performed simultaneously. Patients with a daytime systolic blood pressure (SBP) &gt;135 and/or diastolic blood pressure (DBP) &gt;85 mmHg were randomized to standard treatment (control) or intervention. The intervention was performed by the treating physician and included information on drug levels and a personalized feedback conversation based on a feedback tool. The follow-up period was one year and included visits at 3, 6 and 12 months after the eligibility visit. At each visit an ABPM and DBS were performed.

Results

A total of 53 patients (mean age of 59±11 years, 78.7% male) with at least three months of follow-up were included. The prevalence of RH decreased from 100% in both arms to 75.0% in the intervention arm (p=0.014, n=24) and 58.6% in the control arm (p=0.001, n=29). No improvements were seen in adherence rates over time. Furthermore, no significant differences were found after three months between the two groups in the degree of RH (p=0.214), SBP (p=0.551) or adherence (p=0.746).

Conclusion

Measuring blood pressure and drug levels led to a decrease in the prevalence of RH. However, this improvement could not be linked to the actual intervention or improvement of adherence.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ZonMW

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.

Circulating endothelial cells transiently increase in peripheral blood after kidney transplantation

The diagnosis of kidney allograft rejection is based on late histological and clinical markers. Early, specific and minimally-invasive biomarkers may improve rejection diagnosis. Endothelial cells (EC) are one of the earliest targets in kidney transplant rejection. We investigated whether circulating EC (cEC) could serve as an earlier and less invasive biomarker for allograft rejection. Blood was collected from a cohort of 51 kidney transplant recipients before and at multiple timepoints after transplantation, including during a for cause biopsy. The number and phenotype of EC was assessed by flow-cytometric analysis. Unbiased selection of EC was done using principal component (PCA) analysis. Paired analysis revealed a transient cEC increase of 2.1-fold on the third day post-transplant, recovering to preoperative levels at seventh day post-transplant and onwards. Analysis of HLA subtype demonstrated that cEC mainly originate from the recipient. cEC levels were not associated with allograft rejection, allograft function or other allograft pathologies. However, cEC in patients with allograft rejection and increased levels of cEC showed elevated levels of KIM-1 (kidney injury marker-1). These findings indicate that cEC numbers and phenotype are affected after kidney transplantation but may not improve rejection diagnosis.

Care for the organ transplant recipient on the intensive care unit

All transplant recipients receive tacrolimus, mycophenolate and glucocorticoids and these drugs have many side-effects and drug-drug interactions. Common complications include surgical complications, infections, rejection and acute kidney injury. Infections as CMV and PJP can be prevented with prophylactic treatment. Given the complexity of organ transplant recipients a multi-disciplinary team of intensivists, surgeons, pharmacists and transplant specialists is essential. After heart transplantation a temporary pacemaker is required until the conduction system recovers. Stiffening of the heart and increased cardiac markers indicate rejection. An endomyocardial biopsy is performed via the right jugular vein, necessitating its preservation. For lung transplant patients, early intervention for aspiration is warranted to prevent chronic rejection. Risk of any infection is high, requiring active surveillance and intensive treatment, mainly of fungal infections. The liver is immunotolerant requiring lower immunosuppression. Transplantation surgery is often accompanied by massive blood loss and coagulopathy. Other complications include portal vein or hepatic artery thrombosis and biliary leakage or stenosis. Kidney transplant recipients have a high risk of cardiovascular disease and posttransplant anemia should be treated liberally. After postmortal transplantation, delayed graft function is common and dialysis is continued. Ureteral anastomosis complications can be diagnosed with ultrasound.

A population pharmacokinetic model to predict the individual starting dose of tacrolimus in adult renal transplant recipients

Aims

The aims of this study were to describe the pharmacokinetics of tacrolimus immediately after kidney transplantation, and to develop a clinical tool for selecting the best starting dose for each patient.

Methods

Data on tacrolimus exposure were collected for the first 3 months following renal transplantation. A population pharmacokinetic analysis was conducted using nonlinear mixed‐effects modelling. Demographic, clinical and genetic parameters were evaluated as covariates.

Results

A total of 4527 tacrolimus blood samples collected from 337 kidney transplant recipients were available. Data were best described using a two‐compartment model. The mean absorption rate was 3.6 h⁻¹, clearance was 23.0 l h^–1 (39% interindividual variability, IIV), central volume of distribution was 692 l (49% IIV) and the peripheral volume of distribution 5340 l (53% IIV). Interoccasion variability was added to clearance (14%). Higher body surface area (BSA), lower serum creatinine, younger age, higher albumin and lower haematocrit levels were identified as covariates enhancing tacrolimus clearance. Cytochrome P450 (CYP) 3A5 expressers had a significantly higher tacrolimus clearance (160%), whereas CYP3A4*22 carriers had a significantly lower clearance (80%). From these significant covariates, age, BSA, CYP3A4 and CYP3A5 genotype were incorporated in a second model to individualize the tacrolimus starting dose: Dosemg=222nghml–1*22.5lh–1*1.0ifCYP3A5*3/*3or1.62ifCYP3A5*1/*3orCYP3A5*1/*1*1.0ifCYP3A4*1or unknownor0.814ifCYP3A4*22*Age56−0.50*BSA1.930.72/1000Both models were successfully internally and externally validated. A clinical trial was simulated to demonstrate the added value of the starting dose model.

Conclusions

For a good prediction of tacrolimus pharmacokinetics, age, BSA, CYP3A4 and CYP3A5 genotype are important covariates. These covariates explained 30% of the variability in CL/F. The model proved effective in calculating the optimal tacrolimus dose based on these parameters and can be used to individualize the tacrolimus dose in the early period after transplantation.

Personalized immunosuppression in elderly renal transplant recipients

The number of elderly people has increased considerably over the last decades, due to a rising life expectancy and ageing populations. As a result, an increased number of elderly with end-stage-renal-disease are diagnosed, for which the preferred treatment is renal transplantation. Over the past years the awareness of the elderly as a specific patient population has grown, which increases the importance of research in this group. Elderly patients often receive kidneys from elderly donors while younger donor kidneys are preferentially reserved for younger recipients. Although the rate of acute rejection after transplantation is lower in the elderly, these rejections may lead to graft loss more frequently, as kidneys from elderly donors have marginal reserve capacity. To prevent acute rejection, immunosuppressive therapy is needed. On the other hand, elderly patients have a higher risk to die from infectious complications, and thus less immunosuppression would be preferable. Immunosuppressive treatment in the elderly is complicated further by changes in the pharmacokinetics and pharmacodynamics, with increasing age. Adjustments in standard immunosuppressive regimes are therefore suggested for this population. An unmet need in transplantation medicine is a tool to guide a personalized approach to immunosuppression. Recently several promising biomarkers that identify injury to the graft at an early stage or predict acute rejection have been identified. Unfortunately, none of these biomarkers were tested specifically in the elderly. We believe there is an urgent need to perform clinical trials investigating novel immunosuppressive regimens in conjunction with biomarker studies in this specific population.

Co-inhibitory profile and cytotoxicity of CD57+ PD-1- T cells in end-stage renal disease patients

Blockade of the CD80/86-CD28 pathway by belatacept after kidney transplantation is associated with an increased risk of rejection compared with standard, calcineurin inhibitor (CNI)-based therapy. CD28^- T cells, which express CD57, are not susceptible to belatacept treatment. High numbers of CD4⁺ CD57⁺ programmed death 1 (PD-1)^- T cells pretransplantation have been associated with a higher chance of rejection, although conflicting data have been reported. To investigate the working mechanism behind this possible higher chance of rejection, we studied the expression of co-inhibitory molecules (CD223, CD244 and PD-1), proliferative capacity and cytotoxic potential of fluorescence activated cell sorted (FACS) CD4⁺ CD57⁺ PD-1^- and CD8⁺ CD57⁺ PD-1^- T cells, and their CD57^- control populations, after alloantigen stimulation. The effect of belatacept on the cytotoxic capacity of pretransplantation peripheral blood mononuclear cells from 20 patients who received belatacept post-transplantation was also tested. Expression of co-inhibitory molecule CD223 increased by approximately 10-fold after allogeneic stimulation in all four T cell subsets. Proliferation and up-regulation of CD244 and PD-1 was observed for CD4⁺ CD57^- PD-1^- T cells after allogeneic stimulation, but no up-regulation of these markers occurred on CD8⁺ T cells or CD4⁺ CD57⁺ PD-1^- T cells. However, CD4⁺ CD57⁺ PD-1^- T cells and, to a lesser extent, CD8⁺ CD57⁺ PD-1^- T cells displayed higher cytotoxicity as indicated by granzyme B expression. Belatacept inhibited the cytotoxic potential of CD4⁺ CD57⁺ PD-1^- T cells (median of inhibition 31%, P < 0·01) and CD8⁺ CD57⁺ PD-1^- T cells (median of inhibition 10%, P < 0·05). In conclusion, alloantigen-activated CD4⁺ CD57⁺ PD-1^- T cells exhibited a less proliferative but more cytotoxic profile than their CD57^- counterparts. Their cytotoxic capacity can be inhibited partly by belatacept and was not associated with development of rejection after kidney transplantation.

Characterization of ectopic lymphoid structures in different types of acute renal allograft rejection

We hypothesize that T cells such as interleukin (IL)-21⁺ B cell lymphoma 6 (BCL6)⁺ T follicular helper cells can regulate B cell-mediated immunity within the allograft during acute T cell-mediated rejection; this process may feed chronic allograft rejection in the long term. To investigate this mechanism, we determined the presence and activation status of organized T and B cells in so-called ectopic lymphoid structures (ELSs) in different types of acute renal allograft rejection. Biopsies showing the following primary diagnosis were included: acute/active antibody-mediated rejection, C4d⁺ (a/aABMR), acute T cell-mediated rejection grade I (aTCMRI) and acute T cell-mediated rejection grade II (aTCMRII). Paraffin sections were stained for T cells (CD3 and CD4), B cells (CD20), follicular dendritic cells (FDCs, CD23), activated B cells (CD79A), immunoglobulin (Ig)D, cell proliferation (Ki67) and double immunofluorescent stainings for IL-21 and BCL6 were performed. Infiltrates of T cells were detected in all biopsies. In aTCMRI, B cells formed aggregates surrounded by T cells. In these aggregates, FDCs, IgD and Ki67 were detected, suggesting the presence of ELSs. In contrast, a/aABMR and aTCMRII showed diffuse infiltrates of T and B cells but no FDCs and IgD. IL-21 was present in all biopsies. However, co-localization with BCL6 was observed mainly in aTCMRI biopsies. In conclusion, ELSs with an activated phenotype are found predominantly in aTCMRI where T cells co-localize with B cells. These findings suggest a direct pathway of B cell alloactivation at the graft site during T cell mediated rejection.

Conversion from tacrolimus to everolimus with complete and early glucocorticoid withdrawal after kidney transplantation: a randomised trial

BACKGROUND

While conversion from cyclosporine to everolimus is well documented, conversion from tacrolimus has been poorly studied. In this randomised, controlled trial the safety and tolerability of switching from tacrolimus to everolimus with glucocorticoid withdrawal after living-donor kidney transplantation was studied.

METHODS

A total of 194 patients were planned to be randomised 1:1 to either continue tacrolimus or to convert to everolimus at month 3 after transplantation. At randomisation, all patients received tacrolimus, mycophenolate mofetil and prednisolone. Everolimus was started in a dose of 1.5 mg twice daily, aiming for predose concentrations of 4-7 ng/ml. Prednisolone was gradually withdrawn in both groups.

RESULTS

The trial was stopped prematurely after the inclusion of 60 patients. The interim analysis showed an unacceptably high rejection rate in the everolimus group as compared with the control group: 30.0% vs. 6.7% (95% CI: 0.047-0.420; p = 0.045). An additional 8 patients stopped everolimus because of toxicity. At the end of follow-up (month 12) only 12 (40%) patients assigned to everolimus were still on the study drug.

CONCLUSIONS

Conversion from tacrolimus to everolimusbased immunosuppression with withdrawal of prednisolone three months after kidney transplantation results in an unacceptably high risk of acute rejection and causes considerable toxicity. Based on our findings, such a switch strategy cannot be recommended.

Systematic review of surgical and medical treatment for tertiary hyperparathyroidism

BACKGROUND

A significant proportion of patients with chronic kidney disease and secondary hyperparathyroidism (HPT) remain hyperparathyroid after kidney transplantation, a state known as tertiary HPT. Without treatment, tertiary HPT can lead to diminished kidney allograft and patient survival. Parathyroidectomy was commonly performed to treat tertiary HPT until the introduction of the calcimimetic drug, cinacalcet. It is not known whether surgery or medical treatment is superior for tertiary HPT.

METHODS

A systematic review was performed and medical literature databases were searched for studies on the treatment of tertiary HPT that were published after the approval of cinacalcet.

RESULTS

A total of 1669 articles were identified, of which 47 were included in the review. Following subtotal and total parathyroidectomy, initial cure rates were 98·7 and 100 per cent respectively, but in 7·6 and 4 per cent of patients tertiary HPT recurred. After treatment with cinacalcet, 80·8 per cent of the patients achieved normocalcaemia. Owing to side-effects, 6·4 per cent of patients discontinued cinacalcet treatment. The literature regarding graft function and survival is limited; however, renal graft survival after surgical treatment appears comparable to that obtained with cinacalcet therapy.

CONCLUSION

Side-effects and complications of both treatment modalities were mild and occurred in a minority of patients. Surgical treatment for tertiary HPT has higher cure rates than medical therapy.

Ferric carboxymaltose-induced hypophosphataemia after kidney transplantation

BACKGROUND

Ferric carboxymaltose (FCM) can induce hypophosphataemia in the general population and patients with chronic kidney disease (CKD). Less is known about the effect of FCM in the kidney transplant population. It has been suggested that fibroblast growth factor 23 (FGF-23)-mediated renal phosphate wasting may be the most likely cause of this phenomenon. In the current study, the effects of FCM on phosphate metabolism were studied in a cohort of kidney transplant recipients.

METHODS

Two index patients receiving FCM are described. Additionally, data of 23 kidney transplant recipients who received a single dose of FCM intravenously between 1 January 2014 and 1 July 2015 were collected. Changes in the serum phosphate concentration were analysed in all subjects. Change in plasma FGF-23 concentrations was analysed in the index patients.

RESULTS

In the two index patients an increase in FGF-23 and a decrease in phosphate concentrations were observed after FCM administration. In the 23 kidney transplant patients, median estimated glomerular filtration rate was 42 ml/min/1.73 m2 ( range 10-90 ml/ min/1.73 m2). Mean phosphate concentration before and after FCM administration was 1.05 ±; 0.35 mmol/l and 0.78 ±; 0.41 mmol/l, respectively (average decrease of 0.27 mmol/l; p = 0.003). In the total population, 13 (56.5%) patients showed a transient decline in phosphate concentration after FCM administration. Hypophosphataemia following FCM administration was severe (i.e. < 0.5 mmol/l) in 8 (34.8%) patients.

CONCLUSION

Administration of a single dose of FCM may induce transient and mostly asymptomatic renal phosphate wasting and hypophosphataemia in kidney transplant recipients. This appears to be explained by an increase in FGF-23 concentration.

Uremia-Associated Premature Aging of T Cells Does Not Predict Infectious Complications After Renal Transplantation

Patients with end-stage renal disease have prematurely aged T cell systems. We tested whether T cell aging parameters were associated with the risk of infections after renal transplantation (RTx). We studied 188 patients over 1 year. Peripheral T cells were analyzed before and at 3 and 6 mo after RTx for frequency of recent thymic emigrants, relative telomere length and differentiation status. These parameters were related to the occurrence of opportunistic and serious infections. Overall, 84 patients developed an infection. In this group, 50 developed an opportunistic infection and 53 developed a serious infection. T cell aging parameters assessed before RTx were not associated with infection risk. The memory T cells showed a decrease within the first 3 mo in both groups (p < 0.001). The CD4(+) memory T cells increased between 3 and 6 mo within the infection group (p = 0.015). The number of CD8(+) memory T cells increased in both groups (p < 0.001) but reached baseline levels only in the infection group. In the infection group, the CD8(+) CD28(null) T cell percentage increased between 3 and 6 mo (p = 0.024), tending to be higher than at baseline (p = 0.061). These differences in post-RTx dynamics resulted from infections. Parameters of uremia-associated premature aging of peripheral T cells do not predict posttransplant infections.

A Randomized Controlled Trial Comparing the Efficacy of Cyp3a5 Genotype-Based With Body-Weight-Based Tacrolimus Dosing After Living Donor Kidney Transplantation

Patients expressing the cytochrome P450 (CYP) 3A5 gene require a higher tacrolimus dose to achieve therapeutic exposure compared with nonexpressers. This randomized-controlled study investigated whether adaptation of the tacrolimus starting dose according to CYP3A5 genotype increases the proportion of kidney transplant recipients being within the target tacrolimus predose concentration range (10-15 ng/mL) at first steady-state. Two hundred forty living-donor, renal transplant recipients were assigned to either receive a standard, body-weight-based or a CYP3A5 genotype-based tacrolimus starting dose. At day 3, no difference in the proportion of patients having a tacrolimus exposure within the target range was observed between the standard-dose and genotype-based groups: 37.4% versus 35.6%, respectively; p = 0.79. The proportion of patients with a subtherapeutic (i.e. <10 ng/mL) or a supratherapeutic (i.e. >15 ng/mL) Tac predose concentration in the two groups was also not significantly different. The incidence of acute rejection was comparable between both groups (p = 0.82). Pharmacogenetic adaptation of the tacrolimus starting dose does not increase the number of patients having therapeutic tacrolimus exposure early after transplantation and does not lead to improved clinical outcome in a low immunological risk population.

Pharmacogenetic aspects of the use of tacrolimus in renal transplantation: recent developments and ethnic considerations

INTRODUCTION

Tacrolimus (Tac) is effective in preventing acute rejection but has considerable toxicity and inter-individual variability in pharmacokinetics and pharmacodynamics. Part of this is explained by polymorphisms in genes encoding Tac-metabolizing enzymes and transporters. A better understanding of Tac pharmacokinetics and pharmacodynamics may help to minimize different outcomes amongst transplant recipients by personalizing immunosuppression.

AREAS COVERED

The pharmacogenetic contribution of Tac metabolism will be examined, with a focus on recent discoveries, new developments and ethnic considerations.

EXPERT OPINION

The strongest and most consistent association in pharmacogenetics is between the CYP3A5 genotype and Tac dose requirement, with CYP3A5 expressers having a ~ 40-50% higher dose requirement compared to non-expressers. Two recent randomized-controlled clinical trials using CYP3A5 genotype, however, did not show a decrease in acute rejections nor reduced toxicity. CYP3A4*22, CYP3A4*26, and POR*28 are also associated with Tac dose requirements and may be included to provide the expected improvement of Tac therapy. Studies focusing on the intracellular drug concentrations and on calcineurin inhibitor-induced nephrotoxicity also seem promising. For all studies, however, the ethnic prevalence of genotypes should be taken into account, as this may significantly impact the effect of pre-emptive genotyping.

Primary Cytomegalovirus Infection Significantly Impacts Circulating T Cells in Kidney Transplant Recipients

Cytomegalovirus (CMV) infection profoundly affects the T cell compartment and is associated with alterations in T cell aging parameters and generation of cytotoxic CD4(+) CD28null T cells. Hence, the effect of a primary CMV infection post-kidney transplantation (KT) on the peripheral T cell compartment was examined. As aging parameters, we determined the T cell differentiation status, T cell receptor excision circle (TREC) content, CD31(+) naïve T cell numbers and relative telomere length (RTL) pre-KT and 12 months post-KT. CMV-seronegative KT recipients, receiving a kidney from a CMV-seropositive donor (D+/R-) were compared to D+/R+ KT recipients. Eleven out of the 22 D+/R- KT recipients had CMV viremia post-KT. They developed CMV-specific CD4(+) and CD8(+) T cells and their T cell compartment shifted towards a more differentiated memory phenotype with expansion of CD4(+) CD28null and CD8(+) CD28null cells. One year post-KT, the CD8(+) T cell count was almost doubled compared to nonviremic D+/R- and D+/R+ KT recipients. In addition, the RTL of the CD8(+) T cell was significantly lower and both the TREC content and CD31(+) naïve T cell numbers significantly decreased. Moreover, primary CMV infection was associated with a negative impact on glomerular filtration rate. In conclusion, primary CMV infection has a substantial impact on the number and phenotype of peripheral T cells and may negatively affect renal allograft function.

Follicular T helper cells and humoral reactivity in kidney transplant patients

Memory B cells play a pivotal role in alloreactivity in kidney transplantation. Follicular T helper (Tfh) cells play an important role in the differentiation of B cells into immunoglobulin-producing plasmablasts [through interleukin (IL)-21]. It is unclear to what extent this T cell subset regulates humoral alloreactivity in kidney transplant patients, therefore we investigated the absolute numbers and function of peripheral Tfh cells (CD4(POS) CXCR5(POS) T cells) in patients before and after transplantation. In addition, we studied their relationship with the presence of donor-specific anti-human leucocyte antigen (HLA) antibodies (DSA), and the presence of Tfh cells in rejection biopsies. After transplantation peripheral Tfh cell numbers remained stable, while their IL-21-producing capacity decreased under immunosuppression. When isolated after transplantation, peripheral Tfh cells still had the capacity to induce B cell differentiation and immunoglobulin production, which could be inhibited by an IL-21-receptor-antagonist. After transplantation the quantity of Tfh cells was the highest in patients with pre-existent DSA. In kidney biopsies taken during rejection, Tfh cells co-localized with B cells and immunoglobulins in follicular-like structures. Our data on Tfh cells in kidney transplantation demonstrate that Tfh cells may mediate humoral alloreactivity, which is also seen in the immunosuppressed milieu.

Tacrolimus predose concentrations do not predict the risk of acute rejection after renal transplantation: a pooled analysis from three randomized-controlled clinical trials(†)

Therapeutic drug monitoring (TDM) for tacrolimus (Tac) is universally applied. However, the concentration-effect relationship for Tac is poorly defined. This study investigated whether Tac concentrations are associated with acute rejection in kidney transplant recipients. Data from three large trials were pooled. We used univariate and multivariate analysis to investigate the relationship between biopsy-proven acute rejection (BPAR) and Tac predose concentration at five time points (day 3, 10 and 14, and month 1 and 6 after transplantation). A total of 136/1304 patients experienced BPAR, giving an overall incidence of 10.4%. We did not find any significant correlations between Tac predose concentrations and the incidence of BPAR at the different time points. In the multivariate analysis, only delayed graft function (DGF) and the use of induction therapy were independently correlated with BPAR, with an odds ratio of 2.7 [95% CI: 1.8-4.0; p < 0.001] for DGF and 0.66 [95% CI: 0.44-0.99; p = 0.049] for induction therapy. The other variables, including the Tac predose concentrations, were not statistically significantly associated with BPAR. We did not find an association between the Tac predose concentrations measured at five time points after kidney transplantation and the incidence of acute rejection occurring thereafter. Based on this study it is not possible to define the optimal target concentrations for Tac.

Treatment of steroid-resistant acute renal allograft rejection with alemtuzumab

Steroid-resistant renal allograft rejections are commonly treated with rabbit antithymocyte globulin (RATG), but alemtuzumab could be an effective, safe and more convenient alternative. Adult patients with steroid-resistant renal allograft rejection treated with alemtuzumab (15-30 mg s.c. on 2 subsequent days) from 2008 to 2012 (n = 11) were compared to patients treated with RATG (2.5-4.0 mg/kg bodyweight i.v. for 10-14 days; n = 20). We assessed treatment-failure (graft loss, lack of improvement of graft function or need for additional anti-rejection treatment), infections during the first 3 months after treatment and infusion-related side effects. In both groups, the median time-interval between rejection and transplantation was 2 weeks, and approximately 75% of rejections were classified as Banff-IIA or higher. Three alemtuzumab-treated patients (27%) experienced treatment failure, compared to eight RATG treated patients (40%, p = 0.70). There was no difference in the incidence of infections. There were mild infusion-related side-effects in three alemtuzumab-treated patients (27%), and more severe infusion-related side effects in 17 RATG-treated patients (85%, p = 0.013). Drug related costs of alemtuzumab-treatment were lower than of RATG-treatment (€1050 vs. €2024; p < 0.01). Alemtuzumab might be an effective therapy for steroid-resistant renal allograft rejections. In contrast to RATG, alemtuzumab is nearly devoid of infusion-related side-effects. These data warrant a prospective trial.

The effects of renal transplantation on circulating dendritic cells

The effects of immunosuppressive agents on T cell function have been well characterized but virtually nothing is known about the effects of renal transplantation on human dendritic cells (DCs). With the use of flow cytometry, we studied the kinetics of myeloid and plasmacytoid DCs in peripheral blood of 24 kidney allograft recipients before and after transplantation, and in 23 donors before and after kidney donation. All patients were treated with tacrolimus, mycophenolate mofetil and prednisone. Surgery resulted in a strong decline in the number of myeloid and plasmacytoid DCs, both in kidney donors and in their recipients. However, in donors this effect was transient, as the numbers of both DC subsets had normalized completely by the third postoperative month. In contrast, the recovery of myeloid DC counts in kidney transplant recipients was only incomplete at the end of the 3-month follow-up, despite tapering of immunosuppression. The seven patients who required additional immunosuppressive treatment because of acute rejection experienced an even more marked decrease in DC counts in the early postoperative period compared with patients who remained rejection-free. Surgical procedures markedly affect the numbers of circulating myeloid and plasmacytoid DCs. Immunosuppressive drugs have important additional in vivo effects on this cell type and impair the reconstitution of the myeloid DC subset in peripheral blood after renal transplantation.

Experience with cyclosporine in endogenous uveitis posterior

Treatment with cyclosporine (CsA) has considerably improved the visual prognosis of patients suffering from endogenous posterior uveitis (EPU). However, the therapeutic benefits of CsA are partially outweighed by its many side effects, most notably nephrotoxicity and hypertension. Low-dose CsA regimens have reduced toxicity but have not been able to completely eliminate this problem. New therapeutic approaches, such as anti-tumor necrosis factor alpha treatment or immunosuppression with drugs including tacrolimus, sirolimus, and interleukin-2 receptor antibodies, are currently under evaluation. Hopefully such strategies will further reduce the morbidity of EPU and minimize the adverse effects associated with conventional therapies.

The relative importance of cyclosporine exposure in heart, kidney or liver transplant recipients on maintenance therapy

We investigated the relationship between cyclosporine exposure and the presence of cyclosporine-related side effects and assessed the advantage of the cyclosporine concentration 2 h post-dose (C(2)) over pre-dose concentration (C(0)) monitoring. Cyclosporine area-under-the-concentration-time curves were measured during the absorption phase (AUC(0-4 h)) in 49 liver, 28 heart and 26 kidney transplant recipients (time since transplantation >6 years) with or without cyclosporine-related side effects on maintenance therapy. The cyclosporine C(0) correlated well with AUC(0-4) (r=0.77), whereas C(2) levels correlated strongly with AUC(0-4) (r=0.92). Although we observed a trend towards higher CsA concentrations in transplant recipients with side effects than in patients without CsA toxicity, the large majority of those differences were not statistically significant. Thus, as cyclosporine exposure was not clearly related to the presence of side effects, and C(0) correlated fairly with AUC(0-4), the advantage of monitoring cyclosporine treatment using C(2) rather than C(0), may be limited for patients on cyclosporine maintenance therapy.

The use of cyclosporine in renal transplantation

The introduction of cyclosporine (CsA) into clinical practice resulted in a dramatic reduction in the incidence and severity of acute rejection. As a result, short-term and medium-term kidney allograft survival increased greatly. However, the long-term patient and graft survival have not improved to a similar degree. This can partly be attributed to the side effects of CsA and partly to the fact that the use of CsA has not led to a reduced incidence of chronic allograft nephropathy. Thus, there has been a continuing search for strategies that minimize CsA toxicity but maintain adequate immunosuppression. This has resulted in the development of the CsA microemulsion formulation and improved methods for therapeutic drug monitoring. With the introduction of newer immunosuppressive drugs, early CsA withdrawal and CsA-free immunosuppressive therapy have become feasible. However, CsA weaning or complete avoidance is associated with a slightly higher risk of acute rejection, and the long-term efficacy and safety of such strategies remain to be established. Therefore, it is to be expected that in the near future CsA will remain part of the standard immunosuppressive regimen in many transplant centers.

Profiles of the acute-phase reactants C-reactive protein and ferritin related to the disease course of patients with systemic lupus erythematosus

OBJECTIVE

To obtain insight in the acute-phase response in SLE.

METHODS

The clinical history, SLEDAI, CRP and ferritin concentrations were analysed throughout the disease course of 10 SLE patients.

RESULTS

During a mean follow-up of 4.8 years, 10 exacerbations (SLEDAI > or = 11) occurred. Throughout the disease course, CRP and SLEDAI correlated positively in 5 patients, whereas the correlation between SLEDAI and ferritin was positive in 7 patients. However, elevated CRP concentrations together with elevated ferritin levels were only observed during 4 exacerbations. Ferritin concentrations were exceptionately high (> 1500 microg/L) during 4 flare-ups. CRP and ferritin levels remained normal during 5 exacerbations.

CONCLUSION

SLE is characterised by highly variable and unusual CRP and ferritin responses that do not always reflect the extent of inflammation in individual patients. Despite severe disease activity, ferritin levels can remain well within the normal range, limiting its clinical usefulness as a marker for disease activity.

[Kidney transplantation: more kidneys from living donors, individualised immunosuppression and better results]

In the period 1996-2001, the number of transplanted postmortal kidneys decreased from 425 to 380, while at the same time the number of kidneys transplanted from living donors increased from 81 in 1996 to 155 per year in 2001. There was a striking increase in the proportion of living non-related donors (59/155). Although the short-term results of kidney transplantation have improved, and kidneys are very rarely lost as a consequence of acute rejection, the average life of a transplanted kidney has scarcely improved. Chronic allograft dysfunction is now the major cause of transplant loss. This process is hardly influenced by the immunosuppressive drugs currently used. To improve the cardiovascular risk profile, several centres discontinue the use of cyclosporin, tacrolimus or prednisone at 6 or 12 months after transplantation or substitute these with other drugs. This is complicated by acute rejection episodes in 10-20% of patients. With the arrival of a number of new immunosuppressive drugs the risk of rejection might be reduced.

[Twenty-five years of cyclosporin use in transplantation medicine]

Cyclosporin has greatly improved the short and medium-term outcomes for solid organ transplantation. However, the effect on the long-term outcome has been less impressive. This can partly be attributed to the side effects of cyclosporin, and partly to the fact that the use of cyclosporin has not led to a reduced incidence of chronic allograft nephropathy. Efforts to minimise these side effects have led to the development of the microemulsion form of cyclosporin and improved methods for therapeutic drug monitoring (dosage based on blood levels instead of body weight). Finally, the introduction of new immunosuppressive drugs has made it possible to further reduce the dose of cyclosporin; this might eventually lead to cyclosporin-free immunosuppressive regimens.

A high prevalence of culture-positive extrapulmonary tuberculosis in a large Dutch teaching hospital

BACKGROUND

In the Netherlands the incidence of tuberculosis (TB) has increased during the last decade. Growing immigration and international travel were important determining factors. To determine if this has resulted in altered clinical manifestations of the disease, we assessed the clinical spectrum of all TB cases diagnosed at our hospital in the period 1994 to 2000.

METHODS

All culture-proven TB cases during the study period were retrospectively reviewed for clinical and demographic data.

RESULTS

Sixty-five patients were identified. Solitary pulmonary TB was diagnosed in 33.9%, extrapulmonary TB in 51.8% and combined pulmonary and extrapulmonary TB in 14.3% of all cases. Patients were of foreign descent in 78.6% of all cases. Incidence peaked between 15 to 45 years. Decreased immunity was an important determining factor in the older patients. Presenting symptoms were mostly aspecific causing an important doctor's delay in establishing the diagnosis in 25%. Mortality was 3.6% and isoniazid resistance 3.6%

CONCLUSIONS

Our data suggest an increase in the percentage of extrapulmonary TB concomitantly with an increasing percentage of patients of foreign descent. Because of aspecific presenting symptoms, TB was often diagnosed late. Treatment is mainly hindered by non-compliance and a high index of suspicion is necessary in making the diagnosis.

Cardiac tamponade secondary to chest tube placement

A 69-year-old woman was hospitalized because of a left-sided pneumothorax due to chronic obstructive pulmonary disease. During chest tube placement she developed hypotension and a decrease in peripheral oxygen saturation. A diagnosis of heart tamponade was made and the patient was treated successfully with pericardiocentesis and placement of a pericardial drain. Cardiac tamponade following chest tube placement is a rare and serious complication. When the clinical condition deteriorates following chest tube insertion, cardiac tamponade should be considered.