Two hundred living donor kidney transplantations under alemtuzumab induction and tacrolimus monotherapy: 3-year follow-up

A Phase I/IIa study of autologous tolerogenic dendritic cells immunotherapy in kidney transplant recipients

Kidney transplant survival is shortened by chronic rejection and side effects of standard immunosuppressive drugs. Cell-based immunotherapy with tolerogenic dendritic cells has long been recognized as a promising approach to reduce general immunosuppression. Published trials report the safety and the absence of therapy-related adverse reactions in patients treated with tolerogenic dendritic cells suffering from several inflammatory diseases. Here, we present the first phase I clinical trial results using human autologous tolerogenic dendritic cells (ATDC) in kidney transplantation. Eight patients received ATDC the day before transplantation in conjunction with standard steroids, mycophenolate mofetil and tacrolimus immunosuppression with an option to taper mycophenolate mofetil. ATDC preparations were manufactured in a Good Manufacturing Practice-compliant facility and fulfilled cell count, viability, purity and identity criteria for release. A control group of nine patients received the same standard immunosuppression, except basiliximab induction replaced ATDC therapy and mycophenolate tapering was not allowed. During the three-year follow-up, no deaths occurred and there was 100% graft survival. No significant increase of adverse events was associated with ATDC infusion. Episodes of rejection were observed in two patients from the ATDC group and one patient from the control group. However, all rejections were successfully treated by glucocorticoids. Mycophenolate was successfully reduced/stopped in five patients from the ATDC group, allowing tacrolimus monotherapy for two of them. Regarding immune monitoring, reduced CD8 T cell activation markers and increased Foxp3 expression were observed in the ATDC group. Thus, our results demonstrate ATDC administration safety in kidney-transplant recipients.

Tacrolimus Monotherapy is Safe in Immunologically Low-Risk Kidney Transplant Recipients: A Randomized-Controlled Pilot Study

In this randomized-controlled pilot study, the feasibility and safety of tacrolimus monotherapy in immunologically low-risk kidney transplant recipients was evaluated [NTR4824, www.trialregister.nl]. Low immunological risk was defined as maximal 3 HLA mismatches and the absence of panel reactive antibodies. Six months after transplantation, recipients were randomized if eGFR >30 ml/min, proteinuria <50 mg protein/mmol creatinine, no biopsy-proven rejection after 3 months, and no lymphocyte depleting therapy given. Recipients were randomized to tacrolimus/mycophenolate mofetil (TAC/MMF) or to taper and discontinue MMF at month 9 (TACmono). 79 of the 121 recipients were randomized to either TACmono (n = 38) or TAC/MMF (n = 41). Mean recipient age was 59 years and 59% received a living donor transplant. The median follow-up was 62 months. After randomization, 3 TACmono and 4 TAC/MMF recipients experienced a biopsy-proven rejection. At 5 years follow-up, patient survival was 84% in TACmono versus 76% in TAC/MMF with death-censored graft survival of 97% for both groups and no differences in eGFR and proteinuria. Eleven TACmono recipients had an infectious episode versus 22 TAC/MMF recipients (p < 0.03). Donor-specific anti-HLA antibodies were not detected during follow-up in both groups. Tacrolimus monotherapy in selected immunologically low-risk kidney transplant recipients appears safe and reduces the number of infections.

Regulatory T cells for minimising immune suppression in kidney transplantation: phase I/IIa clinical trial

OBJECTIVE

To assess whether reshaping of the immune balance by infusion of autologous natural regulatory T cells (nTregs) in patients after kidney transplantation is safe, feasible, and enables the tapering of lifelong high dose immunosuppression, with its limited efficacy, adverse effects, and high direct and indirect costs, along with addressing several key challenges of nTreg treatment, such as easy and robust manufacturing, danger of over immunosuppression, interaction with standard care drugs, and functional stability in an inflammatory environment in a useful proof-of-concept disease model.

DESIGN

Investigator initiated, monocentre, nTreg dose escalation, phase I/IIa clinical trial (ONEnTreg13).

SETTING

Charité-University Hospital, Berlin, Germany, within the ONE study consortium (funded by the European Union).

PARTICIPANTS

Recipients of living donor kidney transplant (ONEnTreg13, n=11) and corresponding reference group trial (ONErgt11-CHA, n=9).

INTERVENTIONS

CD4+ CD25+ FoxP3+ nTreg products were given seven days after kidney transplantation as one intravenous dose of 0.5, 1.0, or 2.5-3.0×10⁶ cells/kg body weight, with subsequent stepwise tapering of triple immunosuppression to low dose tacrolimus monotherapy until week 48.

MAIN OUTCOME MEASURES

The primary clinical and safety endpoints were assessed by a composite endpoint at week 60 with further three year follow-up. The assessment included incidence of biopsy confirmed acute rejection, assessment of nTreg infusion related adverse effects, and signs of over immunosuppression. Secondary endpoints addressed allograft functions. Accompanying research included a comprehensive exploratory biomarker portfolio.

RESULTS

For all patients, nTreg products with sufficient yield, purity, and functionality could be generated from 40-50 mL of peripheral blood taken two weeks before kidney transplantation. None of the three nTreg dose escalation groups had dose limiting toxicity. The nTreg and reference groups had 100% three year allograft survival and similar clinical and safety profiles. Stable monotherapy immunosuppression was achieved in eight of 11 (73%) patients receiving nTregs, while the reference group remained on standard dual or triple drug immunosuppression (P=0.002). Mechanistically, the activation of conventional T cells was reduced and nTregs shifted in vivo from a polyclonal to an oligoclonal T cell receptor repertoire.

CONCLUSIONS

The application of autologous nTregs was safe and feasible even in patients who had a kidney transplant and were immunosuppressed. These results warrant further evaluation of Treg efficacy and serve as the basis for the development of next generation nTreg approaches in transplantation and any immunopathologies.

TRIAL REGISTRATION

NCT02371434 (ONEnTreg13) and EudraCT:2011-004301-24 (ONErgt11).

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

Eight-year follow-up in pediatric living donor kidney recipients receiving alemtuzumab induction

Recipient lymphocytes are crucial for direct and indirect pathways of allorecognition. We proposed that the administration of alemtuzumab several weeks pretransplantation could eradicate peripheral lymphatic cells and promote donor-specific acceptance. This was a single-center, retrospective review of 101 consecutive living donor kidney transplantations in pediatric patients (age 7 months-18 years), performed between September 2006 and April 2010. IS protocol included two 30 mg doses of alemtuzumab: The first was given 12-29 days prior to transplantation, and the second at the time of transplantation. Maintenance IS was based on combination of low-dose CNI and mycophenolate, with steroids tapered over the first 5 days post-transplantation. Patients were followed for 7.8±1.3 years, and protocol biopsies were taken 1 month, 1, 3, and 5 years post-transplant. The Kaplan-Meier 8-year patient and graft survival rates in the cyclosporine-treated patients were 82.0±7.3% and 71.6±7.3, and in the tacrolimus-treated patients were 97.2±5.4 and 83.8±6.0%. Biopsy-proven acute rejection developed in 35% of cyclosporine-treated patients and in 8% of tacrolimus-treated patients. Alemtuzumab pretreatment prior to LRD kidney transplantation, followed by maintenance immunosuppression with tacrolimus and MMF, is associated with reasonable long-term results in pediatric patients.

Sequential Targeting of CD52 and TNF Allows Early Minimization Therapy in Kidney Transplantation: From a Biomarker to Targeting in a Proof-Of-Concept Trial

Background

There is high medical need for safe long-term immunosuppression monotherapy in kidney transplantation. Selective targeting of post-transplant alloantigen-(re)activated effector-T cells by anti-TNF antibodies after global T cell depletion may allow safe drug minimization, however, it is unsolved what might be the best maintenance monotherapy.

Methods

In this open, prospective observational single-centre trial, 20 primary deceased donor kidney transplant recipients received 2x20 mg Alemtuzumab (d0/d1) followed by 5 mg/kg Infliximab (d2). For 14 days all patients received only tacrolimus, then they were allocated to either receive tacrolimus (TAC, n = 13) or sirolimus (SIR, n = 7) monotherapy, respectively. Protocol biopsies and extensive immune monitoring were performed and patients were followed-up for 60 months.

Results

TAC-monotherapy resulted in excellent graft survival (5yr 92%, 95%CI: 56.6–98.9) and function, normal histology, and no proteinuria. Immune monitoring revealed low intragraft inflammation (urinary IP-10) and hints for the development of operational tolerance signature in the TAC- but not SIR-group. Remarkably, the TAC-monotherapy was successful in all five presensitized (ELISPOT+) patients. However, recruitment into SIR-arm was stopped (after n = 7) because of high incidence of proteinuria and acute/chronic rejection in biopsies. No opportunistic infections occurred during follow-up.

Conclusions

In conclusion, our novel fast-track TAC-monotherapy protocol is likely to be safe and preliminary results indicated an excellent 5-year outcome, however, a full–scale study will be needed to confirm our findings.

Trial Registration

EudraCT Number: 2006-003110-18

Failure of Calcineurin Inhibitor (Tacrolimus) Weaning Randomized Trial in Long-Term Stable Kidney Transplant Recipients

Long-term renal transplant outcome is limited by side effects of immunosuppressive drugs, particularly calcineurin inhibitor (CNI). We assumed that some patients selected for a "low immunological risk of rejection" could be eligible and benefit from a CNI weaning strategy. We designed a prospective, randomized, multicenter, double-blind placebo-controlled clinical study (Eudract: 2010-019574-33) to analyze the benefit-risk ratio of tacrolimus weaning on highly selected patients (≥4 years of transplantation, normal histology, stable graft function, no anti-HLA immunization). The primary endpoint was improvement of renal function. Fifty-two patients were scheduled in each treatment arm, placebo compared to the CNI maintenance arm. Only 10 patients were eligible and randomized. Five patients were assigned to the placebo arm and five were assigned to the tacrolimus maintenance arm. In the tacrolimus maintenance arm, all patients maintained stable graft function and no immunological events occurred. Contrastingly, in the placebo arm, all five patients had to reintroduce a full dose of tacrolimus since three of them presented an acute rejection episode (one humoral, one mixed, and one borderline) and two displayed anti-HLA antibodies without histological lesion (one donor-specific antibodies [DSA] and one non-DSA). Clearly, tacrolimus withdrawal must be avoided even in long-term highly selective stable kidney recipients.

Adverse Outcomes of Tacrolimus Withdrawal in Immune-Quiescent Kidney Transplant Recipients

Concerns about adverse effects of calcineurin inhibitors (CNIs) have prompted development of protocols that minimize their use. Whereas previous CNI withdrawal trials in heterogeneous cohorts showed unacceptable rates of acute rejection (AR), we hypothesized that we could identify individuals capable of tolerating CNI withdrawal by targeting immunologically quiescent kidney transplant recipients. The Clinical Trials in Organ Transplantation-09 Trial was a randomized, prospective study of nonsensitized primary recipients of living donor kidney transplants. Subjects received rabbit antithymocyte globulin, tacrolimus, mycophenolate mofetil, and prednisone. Six months post-transplantation, subjects without de novo donor-specific antibodies (DSAs), AR, or inflammation at protocol biopsy were randomized to wean off or remain on tacrolimus. The intended primary end point was the change in interstitial fibrosis/tubular atrophy score between implantation and 24-month protocol biopsies. Serially collected urine CXCL9 ELISA results were correlated with outcomes. The study was terminated prematurely because of unacceptable rates of AR (4 of 14) and/or de novo DSAs (5 of 14) in the tacrolimus withdrawal arm. Positive urinary CXCL9 predated clinical detection of AR by a median of 15 days. Analyses showed that >16 HLA-DQ epitope mismatches and pretransplant, peripheral blood, donor-reactive IFN-γ ELISPOT assay results correlated with development of DSAs and/or AR on tacrolimus withdrawal. Although data indicate that urinary CXCL9 monitoring, epitope mismatches, and ELISPOT assays are potentially informative, complete CNI withdrawal must be strongly discouraged in kidney transplant recipients who are receiving standard-of-care immunosuppression, including those who are deemed to be immunologically quiescent on the basis of current clinical and laboratory criteria.

Comparison of alemtuzumab vs. antithymocyte globulin induction therapy in primary non-sensitized renal transplant patients treated with rapid steroid withdrawal

Alemtuzumab and rabbit antithymocyte globulin (rATG) are commonly used for induction therapy in renal transplantation. This retrospective, single-center, cohort study evaluated cumulative incidence of one-yr biopsy-proven acute rejection (BPAR) among 200 consecutive primary non-sensitized kidney transplant recipients who received either alemtuzumab (n = 100) or rATG (n = 100) induction followed by rapid steroid taper, tacrolimus, and mycophenolate mofetil. Protocol biopsies, plasma and urine BK virus PCR, serum creatinine and iothalamate glomerular filtration rate (iGFR), were obtained at 1, 4, and 12 months from transplantation. The one-yr BPAR rates were similar between the alemtuzumab and rATG groups; however, rejection Banff IA and higher was more common in the alemtuzumab arm (18% vs. 5%, p = 0.047). After adjusting for confounding variables, alemtuzumab was still associated with Banff IA and higher rejection (adjusted OR: 3.7, CI: 1.2-10.5, p = 0.02). Despite similar rates of BK viremia, more patients in the alemtuzumab arm developed BK nephropathy (16% vs. 3%, p = 0.046). One-year iGFR (53.4 ± 20.2 vs. 71.9 ± 27.2 mL/min/1.73 m(2), p = 0.002) and three-yr graft survival (89.5% vs. 95%, p = 0.05) were lower in the alemtuzumab group. In low immunological risk kidney transplant recipients on steroid-free immunosuppression, alemtuzumab was associated with more severe rejection and BK nephropathy compared to rATG.

Alemtuzumab with corticosteroid minimization for pediatric deceased donor renal transplantation: a seven-yr experience

Alemtuzumab is a monoclonal antibody targeting CD52 receptors on B and T lymphocytes and is an effective induction agent in pediatric renal transplantation. We report a seven-yr experience using alemtuzumab induction and steroid-free protocol in the pediatric population as safe and effective. Twenty-one pediatric deceased donor renal transplants were performed at a single academic institution. All received induction with single-dose alemtuzumab and were maintained on a steroid-free protocol using TAC and MMF immunosuppression. There were 15 males and six females in the study whose ages ranged from one to 19 yr. The average follow-up was 32 months (range from 12 to 78.2 months and median 33.7 ± 23.7 months). All patients had immediate graft function. Graft survival was 95%, and patient survival was 100%. Mean 12 and 36 months eGFR were 63.33 ± 21.01 and 59.90 ± 15.27 mL/min/1.73m(2), respectively. Three patients developed acute T-cell-mediated rejection due to non-adherence while no recipients developed cytomegalovirus infection, PTLD, or polyoma BK viral nephropathy. Steroid avoidance with single-dose alemtuzumab induction provides adequate and safe immunosuppression in pediatric deceased donor renal transplant recipients receiving TAC and low-dose MMF maintenance therapy.

Monoclonal antibody therapy and renal transplantation: focus on adverse effects

A series of monoclonal antibodies (mAbs) are commonly utilized in renal transplantation as induction therapy (a period of intense immunosuppression immediately before and following the implant of the allograft), to treat steroid-resistant acute rejections, to decrease the incidence and mitigate effects of delayed graft function, and to allow immunosuppressive minimization. Additionally, in the last few years, their use has been proposed for the treatment of chronic antibody-mediated rejection, a major cause of late renal allograft loss. Although the exact mechanism of immunosuppression and allograft tolerance with any of the currently used induction agents is not completely defined, the majority of these medications are targeted against specific CD proteins on the T or B cells surface (e.g., CD3, CD25, CD52). Moreover, some of them have different mechanisms of action. In particular, eculizumab, interrupting the complement pathway, is a new promising treatment tool for acute graft complications and for post-transplant hemolytic uremic syndrome. While it is clear their utility in renal transplantation, it is also unquestionable that by using these highly potent immunosuppressive agents, the body loses much of its innate ability to mount an adequate immune response, thereby increasing the risk of severe adverse effects (e.g., infections, malignancies, haematological complications). Therefore, it is extremely important for clinicians involved in renal transplantation to know the potential side effects of monoclonal antibodies in order to plan a correct therapeutic strategy minimizing/avoiding the onset and development of severe clinical complications.

Alemtuzumab induction with tacrolimus monotherapy in 25 pediatric renal transplant recipients

ALA induction in transplantation has been shown to reduce the need for maintenance immunosuppression. We report the outcome of 25 pediatric renal transplants between 2007 and 2010 using ALA induction followed by tacrolimus maintenance monotherapy. Patient ages were 1-19 yr (mean 14 ± 4.1 yr). Time of follow-up was 7-51 months (mean 26 ± 13 months). Tacrolimus monotherapy was maintained in 48% of patients, and glucocorticoids were avoided in 80% of recipients. Mean plasma creatinine and GFR at one yr post-transplant were 0.88 ± 0.3 mg/dL and 104.4 ± 25 mL/min/1.73m(2) , respectively. One, two, and three-yr actuarial patient and graft survival rates were 100%. The incidence of early AR (<12 months after transplantation) was 12%, while the incidence of late AR (after 12 months) was 16%. Forty-four percent of the recipients recovered normal, baseline renal function after an episode of AR, and 44% had persistent renal dysfunction (plasma creatinine 1.0-1.8 mg/dL). One graft was lost four yr after transplantation due to medication non-compliance. Four (16%) patients developed BK or CMV infection. In our experience, ALA induction with tacrolimus monotherapy resulted in excellent short- and mid-term patient and graft survival in low-immunologic risk pediatric renal transplant recipients.

Delayed allograft inflammation following alemtuzumab induction for kidney transplantation

BACKGROUND

In a recent clinical trial in kidney transplant recipients, induction with alemtuzumab and rabbit-antithymocyte globulin (r-ATG) was equally effective in preventing rejection during the first post-transplant year; however, this study did not include protocol biopsies.

METHODS

The aim of this study was to analyze the impact of alemtuzumab induction on rejection and subclinical inflammation during the first post-transplant year compared with a historic control group receiving induction with r-ATG. All patients received tacrolimus and mycophenolate mofetil (MMF).

RESULTS

There were 361 in the alemtuzumab group and 478 in the r-ATG groups. Rejection (excluding Banff borderline), during the first year, occurred in 14% of the alemtuzumab group and 9% of the r-ATG group (p = 0.03). Estimated glomerular filtration rate (GFR) (chronic kidney disease (CKD)-EPI formula) at one yr and graft survival at three yr were similar. On the protocol biopsies, interstitial inflammation (Banff i scores) and tubulitis (Banff t scores) were more likely in the r-ATG group at one month, but at four and 12 months, both inflammation and tubulitis were more likely in the alemtuzumab group.

CONCLUSIONS

We conclude that alemtuzumab induction is associated with delayed inflammation at four and 12 months, but this inflammation did not appear to negatively impact the GFR or graft survival.

Reciprocal interaction between intestinal microbiota and mucosal lymphocyte in cynomolgus monkeys after alemtuzumab treatment

It has been known that the gut microbiota plays a central role in shaping normal mucosal immunity, however, little information is available whether the variability of mucosal lymphocytes impacts the commensal flora. Here, we applied a cynomolgus monkey model to characterize the structure and composition of the gut microbiota in response to lymphocyte depletion and to determine their potential association. Molecular profiling of 16S rDNA showed that the intestinal microbiota composition was perturbed after the depletion of mucosal lymphocytes and were recovered following the repopulation. Some specific bacteria from the orders Lactobacillales, Enterobacteriales and Clostridiales, and the genus Prevotella and Faecalibacterium, were primarily responsible for the variations of the gut microbiota after lymphocyte depletion. Interestingly, the species richness of the ileal mucosal microbiota was associated the proportions of TCRαβ+ or TCRγδ+ T cells (p<0.01). We demonstrate for the first time the feature of intestinal microbiota composition after lymphocyte depletion and provide novel evidence that the perturbation of gut microbiota is associated with lymphocyte depletion. It may contribute to understand the relationship between gut commensal microbiota and mucosal immune system. Study results provide insight into biological activity of alemtuzumab in intestinal barrier in organ transplantation.

Upper-extremity transplantation using a cell-based protocol to minimize immunosuppression

OBJECTIVE

To minimize maintenance immunosuppression in upper-extremity transplantation to favor the risk-benefit balance of this procedure.

BACKGROUND

Despite favorable outcomes, broad clinical application of reconstructive transplantation is limited by the risks and side effects of multidrug immunosuppression. We present our experience with upper-extremity transplantation under a novel, donor bone marrow (BM) cell-based treatment protocol ("Pittsburgh protocol").

METHODS

Between March 2009 and September 2010, 5 patients received a bilateral hand (n = 2), a bilateral hand/forearm (n = 1), or a unilateral (n = 2) hand transplant. Patients were treated with alemtuzumab and methylprednisolone for induction, followed by tacrolimus monotherapy. On day 14, patients received an infusion of donor BM cells isolated from 9 vertebral bodies. Comprehensive follow-up included functional evaluation, imaging, and immunomonitoring.

RESULTS

All patients are maintained on tacrolimus monotherapy with trough levels ranging between 4 and 12 ng/mL. Skin rejections were infrequent and reversible. Patients demonstrated sustained improvements in motor function and sensory return correlating with time after transplantation and level of amputation. Side effects included transient increase in serum creatinine, hyperglycemia managed with oral hypoglycemics, minor wound infection, and hyperuricemia but no infections. Immunomonitoring revealed transient moderate levels of donor-specific antibodies, adequate immunocompetence, and no peripheral blood chimerism. Imaging demonstrated patent vessels with only mild luminal narrowing/occlusion in 1 case. Protocol skin biopsies showed absent or minimal perivascular cellular infiltrates.

CONCLUSIONS

Our data suggest that this BM cell-based treatment protocol is safe, is well tolerated, and allows upper-extremity transplantation using low-dose tacrolimus monotherapy.

Alemtuzumab induction in pediatric kidney transplantation

Recipient parenchymal lymphatic cells are crucial for direct and indirect pathways of allorecognition. We proposed that alemtuzumab, being infused several weeks pretransplant could eradicate peripheral lymphatic cells and promote donor-specific tolerance. We present here a single center, retrospective review of 101 consecutive living-donor kidney transplantations to pediatric patients aged from seven month to 18 yr, performed between September 2006 and April 2010. Immunosupression protocol included two 30 mg doses of alemtuzumab: first given 12-29 d prior to transplantation and second at the time of transplantation. Maintenance immunosupression was based on combination of low dose and wide range CNI and mycophenolate. Patients were followed for 3.8 ± 1.4 yr and protocol biopsies were taken one month, one, and three yr post transplant. The Kaplan-Meier graft and patient survival was 96% and 97% for one yr, 89% and 93% for three yr. Biopsy proven acute rejection developed in 26% patients at one yr and in 35% at two yr, no rejections occurred beyond two yr. We conclude that alemtuzumab pretreatment prior to living related donor kidney transplantation allows to reach satisfactory middle-term results in pediatric patients with wide range and low CNI concentrations.

BK virus replication and nephropathy after alemtuzumab-induced kidney transplantation

BK virus nephropathy (BKVN) is a recognized cause of graft failure in kidney transplant recipients. There are limited data on the epidemiology of BK virus (BKV) infection after alemtuzumab induction. By clinical protocol, the kidney transplant recipients at our center were screened with BKV plasma PCR monthly for the first 4 months posttransplant then every 2-3 months for 2 years. A single center retrospective cohort study of all kidney transplant recipients from January 2008 to August 2010 was conducted to determine incidence and outcomes of BKV infection. Descriptive statistics and Kaplan-Meier analysis was performed. Of 666 recipients, 250 (37.5%) developed viruria, 80 (12%) developed viremia and 31 (4.7%) developed BKVN at a median of 17, 21 and 30 weeks, respectively. Induction with alemtuzumab did not significantly affect incidence of BKVN. Increased recipient age, African American race, acute graft rejection and CMV infection were significantly associated with the development of BKVN in multivariate analysis. The incidence of BK viruria, viremia and nephropathy was not significantly different among kidney transplant recipients who received alemtuzumab induction compared to patients receiving less potent induction.

Alternative approaches to myeloid suppressor cell therapy in transplantation: comparing regulatory macrophages to tolerogenic DCs and MDSCs

Several types of myeloid suppressor cell are currently being developed as cell-based immunosuppressive agents. Despite detailed knowledge about the molecular and cellular functions of these cell types, expert opinions differ on how to best implement such therapies in solid organ transplantation. Efforts in our laboratory to develop a cell-based medicinal product for promoting tolerance in renal transplant patients have focused on a type of suppressor macrophage, which we call the regulatory macrophage (M reg). Our favoured clinical strategy is to administer donor-derived M regs to recipients one week prior to transplantation. In contrast, many groups working with tolerogenic dendritic cells (DCs) advocate post-transplant administration of recipient-derived cells. A third alternative, using myeloid-derived suppressor cells, presumably demands that cells are given around the time of transplantation, so that they can infiltrate the graft to create a suppressive environment. On present evidence, it is not possible to say which cell type and treatment strategy might be clinically superior. This review seeks to position our basic scientific and early-stage clinical studies of human regulatory macrophages within the broader context of myeloid suppressor cell therapy in transplantation.

Long-term effects of alemtuzumab on regulatory and memory T-cell subsets in kidney transplantation

BACKGROUND

Induction with lymphocyte-depleting antibodies is routinely used to prevent rejection but often skews T cells toward memory. It is not fully understood which memory and regulatory T-cell subsets are most affected and how they relate to clinical outcomes.

METHODS

We analyzed T cells from 57 living-donor renal transplant recipients (12 reactive and 45 quiescent) 2.8±1.4 years after alemtuzumab induction. Thirty-four healthy subjects and nine patients with acute cellular rejection (ACR) were also studied.

RESULTS

We found that alemtuzumab caused protracted CD4 more than CD8 T-lymphocyte deficiency, increased proportion of CD4 memory T cells, and decreased proportion of CD4 regulatory T cells. Reactive patients exhibited higher proportions of CD4 effector memory T cells (TEM) and CD8 terminally differentiated TEM (TEMRA), with greater CD4 TEM and CD8 TEMRA to regulatory T cell ratios, than quiescent patients or healthy controls. Patients with ongoing ACR had profound reduction in circulating CD8 TEMRA. Mixed lymphocyte assays showed significantly lower T-cell proliferation to donor than third-party antigens in the quiescent group, while reactive and ACR patients exhibited increased effector molecules in CD8 T cells.

CONCLUSIONS

Our findings provide evidence that T-cell skewing toward TEM may be associated with antigraft reactivity long after lymphodepletion. Further testing of TEM and TEMRA subsets as rejection predictors is warranted.

Antibody induction therapy in adult kidney transplantation: A controversy continues

Antibody induction therapy is frequently used as an adjunct to the maintenance immunosuppression in adult kidney transplant recipients. Published data support antibody induction in patients with immunologic risk to reduce the incidence of acute rejection (AR) and graft loss from rejection. However, the choice of antibody remains controversial as the clinical studies were carried out on patients of different immunologic risk and in the context of varying maintenance regimens. Antibody selection should be guided by a comprehensive assessment of immunologic risk, patient comorbidities, financial burden as well as the maintenance immunosuppressives. Lymphocyte-depleting antibody (thymoglobulin, ATGAM or alemtuzumab) is usually recommended for those with high risk of rejection, although it increases the risk of infection and malignancy. For low risk patients, interleukin-2 receptor antibody (basiliximab or daclizumab) reduces the incidence of AR without much adverse effects, making its balance favorable in most patients. It should also be used in the high risk patients with other medical comorbidities that preclude usage of lymphocyte-depleting antibody safely. There are many patients with very low risk, who may be induced with intravenous steroids without any antibody, as long as combined potent immunosuppressives are kept as maintenance. In these patients, benefits with antibody induction may be too small to outweigh its adverse effects and financial cost. Rituximab can be used in desensitization protocols for ABO and/or HLA incompatible transplants. There are emerging data suggesting that alemtuzumab induction be more successful than other antibody for promoting less intensive maintenance protocols, such as steroid withdrawal, tacrolimus monotherapy or lower doses of tacrolimus and mycophenolic acid. However, the long-term efficacy and safety of these unconventional strategies remains unknown.

An analysis of lymphocyte phenotype after steroid avoidance with either alemtuzumab or basiliximab induction in renal transplantation

Several studies have analyzed the phenotype of repopulated T-lymphocytes following alemtuzumab induction; however there has been less scrutiny of the reconstituted B-cell compartment. In the context of a randomized controlled trial (RCT) comparing alemtuzumab induction with tacrolimus monotherapy against basiliximab induction with tacrolimus and mycophenolate mofetil (MMF) therapy in renal transplantation, we analyzed the peripheral B- and T-lymphocyte phenotypes of patients at a mean of 25 +/- 2 months after transplantation. We examined the relationship between peripheral lymphocyte phenotype and graft function. Patients who received alemtuzumab had significantly higher numbers of B cells including naïve, transitional and regulatory subsets. In contrast, the CD4(+) T-cell compartment was dominated by a memory cell phenotype. Following either basiliximab or alemtuzumab induction patients with lower numbers of B cells or B subsets had significantly worse graft function. For alemtuzumab there was also a correlation between these subsets the stability of graft function and the presence of HLA-specific antibodies. These results demonstrate that a significant expansion of regulatory type B cells is associated with superior graft function and that this pattern is more common after alemtuzumab induction. This phenomenon requires further prospective study to see whether this phenotype could be used to customize immunotherapy.

Some observations on prope tolerance

PURPOSE OF REVIEW

To outline the rationale of powerful depleting induction therapy with alemtuzumab and minimal maintenance immunosuppression after organ transplantation.

RECENT FINDINGS

The original observations in principle have been confirmed by many independent centres.

SUMMARY

Follow-up of the 'prope tolerance' protocol has confirmed a low incidence of rejection, infection and post transplant lymphoproliferative disorder (PTLD). Especially, encouraging results were obtained in African-Americans. There were few side effects and the regimen was well tolerated by patients. Treg cells were observed in the circulation, which could be an important factor in the mechanisms of graft acceptance using a prope tolerance regimen. There was a considerable reduction in the costs of the transplantation procedure. It is suggested that this minimalisation of maintenance immunosuppression is the best therapy currently available that we can offer to our patients.

Kidney transplantation with minimized maintenance: alemtuzumab induction with tacrolimus monotherapy--an open label, randomized trial

BACKGROUND

Immunosuppressive regimens for kidney transplantation which reduce the long-term burden of immunosuppression are attractive, but little data are available to judge the safety and efficacy of the different strategies used. We tested the hypothesis that the simple, cheap, regimen of alemtuzumab induction combined with tacrolimus monotherapy maintenance provided equivalent outcomes to the more commonly used combination of interleukin-2 receptor monoclonal antibody induction with tacrolimus and mycophenolate mofetil combination maintenance, both regimens using steroid withdrawal after 7 days.

METHODS

One hundred twenty-three live or deceased donor renal transplant recipients were randomized 2:1 to receive alemtuzumab/tacrolimus or daclizumab/tacrolimus/mycophenolate. The primary endpoint was survival with a functioning graft at 1 year.

RESULTS

Both regimens produced equivalent, excellent outcomes with the primary outcome measure of 97.6% in the alemtuzumab arm and 95.1% in the daclizumab arm at 1 year (95% confidence interval of difference 6.9% to -1.7%) and at 2 years 92.6% and 95.1%. Rejection was less frequent in the alemtuzumab arm with 1- and 2-year rejection-free survival of 91.2% and 89.9% compared with 82.3% and 82.3% in the daclizumab arm. There were no significant differences in terms of the occurrence of opportunistic infections.

CONCLUSION

Alemtuzumab induction with tacrolimus maintenance monotherapy and short-course steroid use provides a simple, safe, and effective immunosuppressive regimen for renal transplantation.

Allospecific CD154+ T-cytotoxic memory cells identify recipients experiencing acute cellular rejection after renal transplantation

BACKGROUND

The novel, recently described allo (antigen)-specific CD154+T cells were evaluated for their association with acute cellular rejection (ACR) in 43 adult renal transplant recipients receiving steroid-free tacrolimus after alemtuzumab induction.

METHODS

Single blood samples corresponding to "for cause" allograft biopsies were assayed for CD154+naive or memory T-helper or T-cytotoxic cells in 16-hr mixed leukocyte reaction.

RESULTS

Intra- and interassay variation was less than 10% for a variety of conditions. In logistic regression, leave-one-out cross-validation, and receiver-operating characteristic analyses, the rejection-risk threshold of allospecific CD154+T-cytotoxic memory cells (TcMs) associated best with biopsy-proven ACR with a sensitivity/specificity of 88% in 32 of 43 subjects. Sensitivity/specificity of 100%/88% was replicated in blinded prediction in the remaining 11 subjects. Allospecific CD154+TcM correlated inversely with CTLA4+TcM (Spearman r=-0.358, P=0.029) and increased significantly with increasing histological severity of ACR (P=2.99E-05, Kruskall-Wallis).

CONCLUSIONS

The strong association between ACR and allospecific CD154+TcM may be useful in minimizing protocol biopsies among recipients at reduced rejection risk.

Single shot of alemtuzumab as induction therapy after kidney transplantation is sufficient

In an earlier study, we were able to show that Tac monotherapy following 2 × 20 mg alemtuzumab induction is at least as effective as Tac-based triple-drug immunosuppression in cadaveric renal transplantation. We were interested to learn whether 1 × 30 mg of alemtuzumab is as effective as 2 × 20 mg. Patients of the initial study group (group A) received 20 mg alemtuzumab on days 0 and 2, and tac monotherapy from day 2 on. This group acted as control group for the new arm (group C), where patients were given only 1 × 30 mg alemtuzumab on day 0 followed by Tac monotherapy from day 2 on with the same target levels as in the control group. Frequency of rejection at 6 months was 15% in the control group compared to 6% in the study group and 20% at 12 months in group A versus 6% in group C (P = 0.034). Time to rejection was 4.9 months in group A and 0.8 in group C. One-year patient survival was 98.5% in both groups, graft survival 96.9% in group A, and 98.5% in group C. Safety profile was similar in both groups apart from more viral and bacterial infections in group C. Single shot alemtuzumab induction of 30 mg is as effective as 2 × 20 mg in cadaveric renal transplantation.

Cutting Edge: Immunological consequences and trafficking of human regulatory macrophages administered to renal transplant recipients

Regulatory macrophages (M regs) were administered to two living-donor renal transplant recipients. Both patients were minimized to low-dose tacrolimus monotherapy within 24 wk of transplantation and subsequently maintained excellent graft function. After central venous administration, most M regs remained viable and were seen to traffic from the pulmonary vasculature via the blood to liver, spleen, and bone marrow. By 1 y posttransplantation, both patients displayed patterns of peripheral blood gene expression converging upon the IOT-RISET signature. Furthermore, both patients maintained levels of peripheral blood FOXP3 and TOAG-1 mRNA expression within the range consistent with nonrejection. It is concluded that M regs warrant further study as a potential immune-conditioning therapy for use in solid-organ transplantation. The results of this work are being used to inform the design of The ONE Study, a multinational clinical trial of immunomodulatory cell therapy in renal transplantation.

Alemtuzumab in allogeneic hematopoetic stem cell transplantation

INTRODUCTION

With the use of reduced-intensity conditioning (RIC), early toxicity of allogeneic stem cell transplantation (SCT) has been much reduced. Graft-versus-host disease (GvHD) causes morbidities and mortality. Alemtuzumab is a mAb directed against CD52. When administered prior to transplant, it leads to T-cell depletion. Incorporation of alemtuzumab in RIC results in low rates of GvHD and treatment-related mortality (TRM) in haematological diseases, even in the setting of mismatched-donor transplantation.

AREAS COVERED

The use of alemtuzumab for GvHD prophylaxis in SCT. The benefit of alemtuzumab-based conditioning is partially offset by increased disease relapse due to impaired graft-versus-tumor effect (GvT) and by slower immune reconstitution, necessitating special precautions. While GvHD is prevented with alemtuzumab, post-SCT interventions are often required. Most studies find that alemtuzumab-based conditioning results in decreased chronic GvHD and TRM, but also in decreased progression-free survival. Overall survival after 3 - 5 years is usually equivalent and quality of life may be improved because of a lower incidence of sequelae of chronic GvHD. Many aspects of alemtuzumab treatment are under investigation.

EXPERT OPINION

Alemtuzumab reduces GvHD and TRM after SCT. Use of alemtuzumab requires awareness and strict management of the risk of opportunistic infections and of an increased risk of disease recurrence.

Five-year outcomes with alemtuzumab induction after lung transplantation

BACKGROUND

Induction therapy with alemtuzumab, followed by lower than conventional intensity post-transplant immunosuppression (eg, tacrolimus monotherapy), has been associated with reduced morbidity and mortality in abdominal and heart transplantation. We examined 5-year outcomes in lung recipients receiving alemtuzumab in conjunction with reduced-intensity post-transplant immunosuppression (early lower-dose tacrolimus; lower-dose steroids, with or without mycophenolate mofetil), compared with lung recipients receiving other induction agents or no induction in association with post-transplant immunosuppression.

METHODS

A retrospective analysis was performed using prospectively collected data from a single-site clinical database of 336 lung recipients (aged ≥ 18) who received allografts between 1998 and 2005, classified by induction type: alemtuzumab, 127; Thymoglobulin, 43; daclizumab, 73; and none, 93. Survival analyses examined patient and graft survival, and freedom from acute cellular rejection (ACR), lymphocytic bronchiolitis, obliterative bronchiolitis (OB), bronchiolitis obliterans syndrome (BOS), and post-transplant lymphoproliferative disorder (PTLD).

RESULTS

Five-year patient and graft survival differed by group (p = 0.046, p = 0.038, respectively). Alemtuzumab patient/graft survival rates were 59%/59%. Survival rates were 60%/44% for Thymoglobulin, 47%/46% for no induction, and 44%/41% for daclizumab. Freedom from ACR, lymphocytic bronchiolitis, OB, and BOS differed by group (all values, p < 0.008); alemtuzumab recipients showed greater 5-year freedom from each outcome (30%/82%/86%/54%) than Thymoglobulin (20%/54%/62%/27%), daclizumab (19%/55%/70%/43%), and no-induction groups (18%/70%/69%/46%). The groups did not differ in PTLD rates (≥ 94% free of PTLD at 5 years; p = 0.864). Effects were unchanged after controlling for potential covariates.

CONCLUSIONS

Alemtuzumab induction may be associated with improved outcomes in lung transplantation. Randomized controlled trials are needed to establish any effects of this agent.

Early steroid withdrawal in repeat kidney transplantation

BACKGROUND AND OBJECTIVES

Kidney re-transplantation (KRT) candidates are considered at high risk for graft failure. Most of these patients are kept on a chronic steroid maintenance (CSM) regimen. The safety of early steroid withdrawal (ESW) remains unanswered in KRT.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study was aimed at comparing the outcomes of ESW and CSM in KRT. Retrospective analysis of 113 KRT patients (ESW, n=59; CSM, n=54) was performed. All patients received rabbit anti-thymocyte globulin/steroid induction and were maintained on mycophenolate/tacrolimus (±steroids).

RESULTS

One- and 5-year patient survival for the ESW and the CSM group were not significantly different (98 versus 96% and 91 versus 88%, respectively; P=0.991). No significant difference was seen in the graft survival for both groups at 1 and 5 years (98 versus 93% and 80 versus 74%, respectively; P=0.779). Mean 1- and 5-year estimated GFR was not statistically different between the groups (P=0.773 and 0.790, respectively). The incidence of acute rejection at 1 year was 17 and 22% in ESW and CSM patients, respectively (P=0.635). Compared with the ESW group, patients in the CSM group were more likely to be hyperlipidemic (P=0.044), osteoporotic (P=0.010), post-transplant diabetics (P=0.051) and required more medications to control BP (P=0.004).

CONCLUSIONS

ESW seems to be a reasonable approach in KRT recipients because the short and intermediate patient survival, graft survival, and graft function is comparable to CSM immunosuppression.

Alemtuzumab in solid organ transplantation and in composite tissue allotransplantation

Alemtuzumab (Campath®, Genzyme Corporation, MA, USA) is a potent monoclonal antilymphocyte, anti-CD52 antibody. Since the 1980s, alemtuzumab has been used extensively in organ transplantation as an induction agent – also with the aim of avoiding or reducing maintenance immunosuppression. We herein review the literature on alemtuzumab in solid organ and composite tissue allotransplantation with an emphasis on clinical and mechanistic aspects of alemtuzumab. In summary, the use of alemtuzumab in solid organ and composite tissue allotransplantation shows excellent early results and holds potential for wider use in conjunction with immunosuppression minimization protocols.

Prophylaxis of invasive mycoses in solid organ transplantation

Solid organ transplantation is emerging as a lifesaving procedure for increasing numbers of patients, and invasive fungal infections are a significant cause of mortality and morbidity for patients undergoing such procedures. Risks for developing these infections are continuing to evolve, leading to shifts in the epidemiology of invasive mycoses occurring after transplantation. Targeting preventive efforts to select solid organ transplantation groups at highest risk for invasive fungal infections is critical to optimizing prophylaxis strategies. The epidemiology of posttransplantation fungal infections, antifungal drug interactions and side effects, and new diagnostic capabilities should be considered when choosing an approach to antifungal prophylaxis for this population.

Investigation of lymphocyte depletion and repopulation using alemtuzumab (Campath-1H) in cynomolgus monkeys

As the target CD52 molecule is expressed on erythrocytes of most nonhuman primate strains, using alemtuzumab in these species would cause massive hemolysis. Six cynomolgus monkeys of Indonesian origin, screened by agglutination assay for absence of CD52 on erythrocytes, were administered alemtuzumab in a cumulative dose to a maximum of 60 mg/kg. In two monkeys, mycophenolate mofetil (MMF) was added as maintenance therapy. Complete depletion of T and B lymphocytes (>99.5%) was achieved with 20 mg/kg alemtuzumab and was more profound than in monkeys treated with antithymocyte globulin (n = 5), as quantified by flow cytometry. Repopulation was suppressed by weekly injections of 10 mg/kg. Without MMF, repopulation of CD20(+)B cells and CD8(+)T cells was complete within 2 and 3 months, respectively, and repopulation of CD4(+)T cells was 67% after 1 year. MMF significantly delayed CD4(+)T-cell repopulation. Among repopulating CD4(+) and CD8(+) T cells, a phenotypic shift was observed from CD45RA(hi)CD62L(hi) naïve cells toward CD45RA(lo)CD62L(lo) effector memory cells. In lymph nodes, the depletion of naïve cells was more profound than of memory cells, which may have initiated a proliferation of memory cells. This model offers opportunities to investigate lymphocyte depletion/repopulation phenomena, as well as the efficacy of alemtuzumab in preclinical transplantation models.

Steroid-free maintenance immunosuppression in kidney transplantation: is it time to consider it as a standard therapy?

Steroid-free immunosuppression in kidney transplantation has been gaining popularity over the past decade, as documented by a continuous and steady rise in the number of kidney transplant patients discharged on steroid-free regimens. This increased interest in steroid-free immunosuppression is fueled by the recognition that half of transplant loss is related to patient death due to cardiovascular disease and/or infectious complications and that the long-term use of steroids contributes to such elevated cardiovascular morbidity and mortality. The availability of newer and more potent immunosuppressive agents has furthered such interest. Many clinical trials over the past two decades have demonstrated the feasibility of steroid-free regimens, at the expense of a slight increase in the rate of acute rejection, which is an important end point in any clinical trial of relatively short duration. The largest epidemiological study to date has reassured the transplant community that the selective use of steroid-free immunosuppression in kidney transplant patients provides no inferior outcome in patient and graft survival at intermediate term. Steroid-free regimens have the potential to improve cardiovascular risk profile. The challenges that remain are to identify the subset of kidney transplant patients who may not benefit from steroid-free immunosuppression and to demonstrate the survival advantage of steroid-free immunosuppresion in suitable kidney transplant candidates.