Alemtuzumab (Campath-1H) and tacrolimus monotherapy after renal transplantation: results of a prospective randomized trial

Long-Term Infectious and Noninfectious Outcomes of Monthly Alemtuzumab as a Calcineurin Inhibitor- and Steroid-Free Regimen for Pancreas Transplant Recipients

Multiple doses of alemtuzumab for immunosuppressive therapy of patients with hematologic malignancies and hematopoietic stem cell transplant have been associated with a high rate of infection. In transplantation, limited alemtuzumab dosing has been successfully used as induction immunosuppression. The effect of multiple doses of alemtuzumab, used as maintenance therapy to minimize steroid and/or calcineurin inhibitor toxicity in solid organ transplant recipients, is unknown. We evaluated the infectious and noninfectious outcomes of 179 pancreas transplant recipients treated with alemtuzumab for induction and maintenance therapy (extended alemtuzumab exposure (EAE)) from 2/28/2003 through 8/31/2005, compared with 159 pancreas transplant recipients with standard induction and maintenance (SIM) therapy performed before (1/1/2002 until 12/31/2002) and after (1/1/2006 until 12/31/2006) the implementation of EAE. EAE was associated with higher risk of overall infections (hazard ratio (HR) 1.33 (1.06–1.66), P=0.01), bacterial infections (HR 1.33 (1.05–1.67), P=0.02), fungal infections (HR 1.86 (1.28–2.71), P < 0.01), and cytomegalovirus infections (HR 2.29 (1.39–3.77), P < 0.01). In addition, EAE was associated with higher risk of acute cellular rejection (HR 2.09 (1.46–2.99), P < 0.01). In conclusion, while a limited alemtuzumab dosing is safe and effective for induction therapy in pancreas transplantation, EAE combined with steroid and calcineurin minimization is associated with a high risk of infectious complications and acute cellular rejection.

Low-dose alemtuzumab induction in a tailored immunosuppression protocol for sensitized kidney transplant recipients

Background

Induction therapy is crucial in kidney transplantation and constitutes an important cornerstone for long-term allograft survival. Alemtuzumab is a depleting CD52-specific antibody with T- and B-cell activity, leading to prolonged lymphocyte depletion for up to 12 months, with profound immunosuppression and an associated risk of serious infections. Current concepts aim to optimize dosing strategies to reduce side effects. Here we present data from an ongoing centre protocol consisting of low-dose alemtuzumab induction and tailored immunosuppression in sensitized patients undergoing kidney transplantation.

Methods

10-year results of the protocol were analysed. Low-dose alemtuzumab induction consisted of a single dose of 20 mg intraoperatively, followed by tacrolimus and corticosteroids for initial immunosuppression, with mycophenolate mofetil suspended until a total lymphocyte count (TLC) >5% or 200/μl was reached.

Results

Between 01/2007 and 04/2017, 46 patients were treated in accordance with the protocol in 48 kidney transplantations. Median PRA_max was 43 [22-76; IQR] %; all patients had negative CDC-crossmatch prior to transplantation. Low-dose alemtuzumab was well tolerated. Median time to TLC recovery was 77 [62-127; IQR] d. Within a median follow-up of 3.3 [1.5-5.6; IQR] years, 12 (25%) patients developed BPAR, 10 of which were antibody-mediated (3 acute, 7 chronic ABMR). Death-censored 5-year allograft survival was 79.2%, with an excellent allograft function at the end of follow-up. There was no increased rate of infections, in particular viral infections.

Conclusions

Our protocol, comprising low-dose alemtuzumab induction, initial suspension of mycophenolate mofetil and triple maintenance immunosuppression, provides excellent patient and allograft outcome in sensitized renal allograft recipients.

Outcomes of Deceased Donor Kidney Transplantation Using Expanded Criteria Donor Kidneys Following Pulsatile Preservation

Aim

We compared the outcomes of transplanting expanded criteria donor (ECD) kidneys undergoing machine perfusion (MP) versus cold storage (CS).

Material and methods

Data on all expanded criteria deceased donor kidney transplants performed at the University of Pittsburgh Medical Center from January 2003 through December 2012 were collected from an in-house electronic repository. There were 78 patients in the MP group and 101 patients in the CS group. The majority of the ECD kidneys were imported from other organ procurement organizations: 69 of 73 in the MP group (94.5%, 5 from unknown sources); and 90 of 99 in the CS group (91%), 2 from an unknown source). Most of the patients in the MP group (77 of 78) received a combination of MP and static CS. MP was performed just prior to transplantation in all MP patients. We used descriptive statistics to characterize our sample. We used logistic regression analysis to model the binary outcome of delayed graft function (DGF; i.e., “yes/no”) and Cox (proportional hazard) regression to model time until graft failure. The Kaplan-Meier product-limit method was used to estimate survival curves for graft and patient survival.

Results

A total of 179 transplants were done from ECD donors (MP, 78; CS, 101). The mean static cold storage time was 14 ± 4.1 hours and the mean machine perfusion time was 11.2 ± 6.3 hours in the MP group. The donor creatinine was higher (1.3 ± 0.6 mg/dl vs. 1.2 ± 0.4 mg/dl, p = 0.01) and the cold ischemia time was longer (28.9 ± 10 hours vs. 24 ± 7.9 hours, p = 0.0003) in the MP patients. There were no differences between the two groups in DGF rate (20.8% [MP] vs. 25.8% [CS], p = 0.46), six-year patient survival (74% [MP] vs. 63.2% [CS], p = 0.11), graft survival (64.3% [MP] vs. 51.5% [CS], p = 0.22), and serum creatinine levels (1.5 mg/dl vs. 1.5 mg/dl) on univariate analysis. On unadjusted analysis, MP subjects without DGF had longer graft survival compared to CS subjects with DGF (p < 0.0032) and MP subjects with DGF (p < 0.0005). MP subjects without DGF had longer death-censored graft survival compared to CS subjects with DGF (p < 0.0077) and MP subjects with DGF (p < 0.0016). However, on regression analysis, MP subjects had longer graft survival than CS subjects when DGF was not present. MP subjects without DGF had longer patient survival compared to CS subjects with DGF (p < 0.0289), on unadjusted analysis. MP subjects had a reduced risk of graft failure (hazard ratio [HR], 0.34; 95% confidence interval [CI], 0.17, 0.68) and death-censored graft failure (HR, 0.44; 95% CI, 0.19, 1.00), compared to CS subjects when DGF was not present.

Conclusions

Reduction of DGF rates for imported ECD kidneys is vital to optimize outcomes and increase their utilization. One strategy to decrease DGF rates may be to reduce static CS time during transportation, by utilizing a portable kidney perfusion machine.

Mesenchymal stromal cells for tolerance induction in organ transplantation

The primary challenge in organ transplantation continues to be the need to suppress the host immune system long-term to ensure prolonged allograft survival. Long-term non-specific immunosuppression can, however, result in life-threatening complications. Thus, efforts have been pursued to explore novel strategies that would allow minimization of maintenance immunosuppression, eventually leading to transplant tolerance. In this scenario, bone marrow-derived mesenchymal stromal cells (MSC), given their unique immunomodulatory properties to skew the balance between regulatory and memory T cells, have emerged as potential candidates for cell-based therapy to promote immune tolerance. Here, we review our initial clinical experience with bone marrow-derived MSC in living-donor kidney transplant recipients and provide an overview of the available results of other clinical programs with MSC in kidney and liver transplantation, highlighting hurdles and success of this innovative cell-based therapy.

Alemtuzumab Induction Is Associated With an Equalization of Outcomes Between White and African American Kidney Transplant Recipients

OBJECTIVES

Our aim was to assess outcomes in White and African American kidney transplant recipients after induction with alemtuzumab.

MATERIALS AND METHODS

We performed a retrospective study of 464 patients who received deceased-donor kidney transplants and were induced with alem-tuzumab between March 2006 and May 2015. We evaluated ethnic influences on patient and graft survival, delayed graft function, allograft failure, and rejection.

RESULTS

There were 337 White (67.3%) and 127 African American (25.3%) patients. We observed no significant differences in 1-, 3-, 5-, and 7- year death-censored graft survival. We also observed no significant differences in 1-, 3-, and 5-year patient survival rates. Having African American ethnicity was not a significant predictor of rejection, graft survival, or patient survival.

CONCLUSIONS

Our results indicate that recipient ethnicity is not a predictor of rejection, graft survival, or patient survival. White and African American kidney transplant recipients induced with alemtuzumab experienced an equalization of outcomes.

Comparative efficacy and safety of antibody induction therapy for the treatment of kidney: a network meta-analysis

To evaluate the efficacy and safety of antibody induction therapies in kidney transplantation. Systematic literature searches were undertaken using MEDLINE, Embase, and Cochrane Library database from 1980 to 2016. Randomized controlled trials (RCTs) comparing three antibody induction therapies (alemtuzumab, interleukin-2 receptor antibodies and antithymocyte globulin) between each other were identified. Bayesian network meta-analysis was used to combine both the direct and indirect evidence on treatment efficacy and its safety. Antibody induction therapy studies, comprising of 18 RCTs (3444 kidney transplant recipients), were included. Overall, alemtuzumab treatment was superior to the ATG group (OR: 0.49, 95% CI: 0.32 to 0.71) and IL-2RAs group (OR: 0.36, 95% CI: 0.25 to 0.52) for reducing the 1-year acute rejection in kidney transplant recipients. Although alemtuzumab treatment was nearly same with ATG group and IL-2RAs group in improving patient survival and renal function, it can reduce the adverse effects of cytomegalovirus infection more efficiently than ATG group (OR: 0.59, 95% CI: 0.32 to 0.95) and IL-2RAs group (OR: 1.08, 95% CI: 0.61 to 1.73). Alemtuzumab was not associated with increased other adverse effects. Alemtuzumab treatment is safe and effective for kidney transplant recipients. No serious adverse effects were observed in trials or in general populations.

Alemtuzumab versus antithymocyte globulin induction therapies in kidney transplantation patients: A systematic review and meta-analysis of randomized controlled trials

Alemtuzumab (ALEM) is widely used as an induction therapy for organ transplantation, and numerous randomized controlled trials (RCTs) have been published to evaluate its efficacy and safety in kidney transplantation as compared with antithymocyte globulin (ATG). The purpose of this study was to compare the benefits and safety of ALEM with those of ATG for induction therapy.A systematic literature search in three electronic databases, including PubMed, EmBase, and Cochrane Library, since inception through October 2016, was conducted to identify potential RCTs for inclusion. Trials that investigated the risk of biopsy-proven acute rejection (BPAR), mortality, graft failure, delayed graft function (DGF), chronic allograft nephropathy (CAN), infections, cytomegalovirus (CMV) infections, new-onset diabetes mellitus after transplant (NODAT), and granulocyte colony stimulation factor (GCSF) use in kidney transplant recipients who received ALEM or ATG as an induction therapy were included. Relative risk (RR) and 95% confidence intervals (CIs) were calculated using a random-effects model.Six RCTs involving 446 kidney transplantation patients were included in this meta-analysis. The effects of ALEM therapy were not significantly different from those of ATG therapy, including the incidence of BPAR (RR: 0.77; 95% CI: 0.51-1.18; P = .229), mortality (RR: 0.64; 95% CI: 0.30-1.39; P = .263), graft failure (RR: 0.81; 95% CI: 0.49-1.33; P = .411), DGF (RR: 1.00; 95% CI: 0.60-1.67; P = .999), CAN (RR: 1.42; 95% CI: 0.44-4.57; P = .556), infections (RR: 1.00; 95% CI: 0.74-1.35; P = .989), CMV infections (RR: 0.70; 95% CI: 0.38-1.30; P = .263), NODAT (RR: 0.50; 95% CI: 0.18-1.36; P = .174), and GCSF use (RR: 1.16; 95% CI: 0.81-1.66; P = .413). Sensitivity analyses were consistent with the overall analysis for all effects except CAN, suggesting that the risk of CAN might be higher with ALEM therapy than ATG therapy (RR: 2.45; 95% CI: 1.02-5.94; P = .046).The findings of this study suggest that the beneficial effects of ALEM therapy are greater than those of ATG therapy in kidney transplantation patients; however, the effects were not statistically significant because of the limited number of trials. Further large-scale RCTs are needed to verify the treatment effects of ALEM.

Safety and Efficacy of Alemtuzumab Induction in Highly Sensitized Pediatric Renal Transplant Recipients

BACKGROUND

Studies show that alemtuzumab, a potent lymphocyte-depleting agent, is well tolerated in pediatric renal transplantation. We report on the use of alemtuzumab induction in highly HLA sensitized (HS) pediatric kidney transplant patients.

METHODS

Fifty pediatric renal transplants were performed from 1/2009-12/2014. 15 HS patients received IVIG (2 g/kg ×2 doses)/rituximab (375 mg/m ×1) for desensitization with alemtuzumab induction (15-30 mg, 1 dose, subcutaneous), whereas 35 nonsensitized patients received anti-IL-2R. Graft survival and infections were compared between 2 groups.

RESULTS

All HS patients had received a prior transplant and were older with lower risk for viral infections due to serostatus. Patient survival was 100%, and graft outcomes were similar with mean 1-year creatinine of 1.03 ± 0.45 versus 0.99 ± 0.6 (P = 0.48). Although a higher incidence of acute cellular rejection was seen in HS patients receiving alemtuzumab (P = 0.001), there was a nonsignificant difference in antibody-mediated rejection. White blood cell and absolute lymphocyte count were significantly lower in alemtuzumab group at 30 days (P < 0.0001) and at 1 year (P = 0.026 and P = 0.001), respectively. There was no significant difference in bacterial, viral, or fungal infections after transplant.

CONCLUSIONS

Alemtuzumab induction with desensitization led to nearly equivalent graft survival and functional outcomes in HS pediatric patients as nonsensitized patients receiving anti-IL-2R induction. With this small sample size, we observed significant reduction of white blood cell and absolute lymphocyte count up to 1 year posttransplant. The risk of infection was comparable between the 2 groups; however, patients who received alemtuzumab were older and at lower risk of viral infection due to serostatus.

Polyclonal and monoclonal antibodies for induction therapy in kidney transplant recipients

BACKGROUND

Prolonging kidney transplant survival is an important clinical priority. Induction immunosuppression with antibody therapy is recommended at transplantation and non-depleting interleukin-2 receptor monoclonal antibodies (IL2Ra) are considered first line. It is suggested that recipients at high risk of rejection should receive lymphocyte-depleting antibodies but the relative benefits and harms of the available agents are uncertain.

OBJECTIVES

We aimed to: evaluate the relative and absolute effects of different antibody preparations (except IL2Ra) when used as induction therapy in kidney transplant recipients; determine how the benefits and adverse events vary for each antibody preparation; determine how the benefits and harms vary for different formulations of antibody preparation; and determine whether the benefits and harms vary in specific subgroups of recipients (e.g. children and sensitised recipients).

SEARCH METHODS

Randomised controlled trials (RCTs) comparing monoclonal or polyclonal antibodies with placebo, no treatment, or other antibody therapy in adults and children who had received a kidney transplant.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing monoclonal or polyclonal antibodies with placebo, no treatment, or other antibody therapy in adults and children who had received a kidney transplant.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) together with their 95% confidence intervals (CI).

MAIN RESULTS

We included 99 studies (269 records; 8956 participants; 33 with contemporary agents). Methodology was incompletely reported in most studies leading to lower confidence in the treatment estimates.Antithymocyte globulin (ATG) prevented acute graft rejection (17 studies: RR 0.63, 95% CI 0.51 to 0.78). The benefits of ATG on graft rejection were similar when used with (12 studies: RR 0.61, 0.49 to 0.76) or without (5 studies: RR 0.65, 0.43 to 0.98) calcineurin inhibitor (CNI) treatment. ATG (with CNI therapy) had uncertain effects on death (3 to 6 months, 3 studies: RR 0.41, 0.13 to 1.22; 1 to 2 years, 5 studies: RR 0.75, 0.27 to 2.06; 5 years, 2 studies: RR 0.94, 0.11 to 7.81) and graft loss (3 to 6 months, 4 studies: RR 0.60, 0.34 to 1.05; 1 to 2 years, 3 studies: RR 0.65, 0.36 to 1.19). The effect of ATG on death-censored graft loss was uncertain at 1 to 2 years and 5 years. In non-CNI studies, ATG had uncertain effects on death but reduced death-censored graft loss (6 studies: RR 0.55, 0.38 to 0.78). When CNI and older non-CNI studies were combined, a benefit was seen with ATG at 1 to 2 years for both all-cause graft loss (7 studies: RR 0.71, 0.53 to 0.95) and death-censored graft loss (8 studies: RR 0.55, 0.39 to 0.77) but not sustained longer term. ATG increased cytomegalovirus (CMV) infection (6 studies: RR 1.55, 1.24 to 1.95), leucopenia (4 studies: RR 3.86, 2.79 to 5.34) and thrombocytopenia (4 studies: RR 2.41, 1.61 to 3.61) but had uncertain effects on delayed graft function, malignancy, post-transplant lymphoproliferative disorder (PTLD), and new onset diabetes after transplantation (NODAT).Alemtuzumab was compared to ATG in six studies (446 patients) with early steroid withdrawal (ESW) or steroid minimisation. Alemtuzumab plus steroid minimisation reduced acute rejection compared to ATG at one year (4 studies: RR 0.57, 0.35 to 0.93). In the two studies with ESW only in the alemtuzumab arm, the effect of alemtuzumab on acute rejection at 1 year was uncertain compared to ATG (RR 1.27, 0.50 to 3.19). Alemtuzumab had uncertain effects on death (1 year, 2 studies: RR 0.39, 0.06 to 2.42; 2 to 3 years, 3 studies: RR 0.67, 95% CI 0.15 to 2.95), graft loss (1 year, 2 studies: RR 0.39, 0.13 to 1.30; 2 to 3 years, 3 studies: RR 0.98, 95% CI 0.47 to 2.06), and death-censored graft loss (1 year, 2 studies: RR 0.38, 0.08 to 1.81; 2 to 3 years, 3 studies: RR 2.45, 95% CI 0.67 to 8.97) compared to ATG. Creatinine clearance was lower with alemtuzumab plus ESW at 6 months (2 studies: MD -13.35 mL/min, -23.91 to -2.80) and 2 years (2 studies: MD -12.86 mL/min, -23.73 to -2.00) compared to ATG plus triple maintenance. Across all 6 studies, the effect of alemtuzumab versus ATG was uncertain on all-cause infection, CMV infection, BK virus infection, malignancy, and PTLD. The effect of alemtuzumab with steroid minimisation on NODAT was uncertain, compared to ATG with steroid maintenance.Alemtuzumab plus ESW compared with triple maintenance without induction therapy had uncertain effects on death and all-cause graft loss at 1 year, acute rejection at 6 months and 1 year. CMV infection was increased (2 studies: RR 2.28, 1.18 to 4.40). Treatment effects were uncertain for NODAT, thrombocytopenia, and malignancy or PTLD.Rituximab had uncertain effects on death, graft loss, acute rejection and all other adverse outcomes compared to placebo.

AUTHORS' CONCLUSIONS

ATG reduces acute rejection but has uncertain effects on death, graft survival, malignancy and NODAT, and increases CMV infection, thrombocytopenia and leucopenia. Given a 45% acute rejection risk without ATG induction, seven patients would need treatment to prevent one having rejection, while incurring an additional patient experiencing CMV disease for every 12 treated. Excluding non-CNI studies, the risk of rejection was 37% without induction with six patients needing treatment to prevent one having rejection.In the context of steroid minimisation, alemtuzumab prevents acute rejection at 1 year compared to ATG. Eleven patients would require treatment with alemtuzumab to prevent 1 having rejection, assuming a 21% rejection risk with ATG.Triple maintenance without induction therapy compared to alemtuzumab combined with ESW had similar rates of acute rejection but adverse effects including NODAT were poorly documented. Alemtuzumab plus steroid withdrawal would cause one additional patient experiencing CMV disease for every six patients treated compared to no induction and triple maintenance, in the absence of any clinical benefit. Overall, ATG and alemtuzumab decrease acute rejection at a cost of increased CMV disease while patient-centred outcomes (reduced death or lower toxicity) do not appear to be improved.

Alemtuzumab Induction and Delayed Acute Rejection in Steroid-Free Simultaneous Pancreas-Kidney Transplant Recipients

Supplemental digital content is available in the text.

Background

The optimal immunosuppressive regimen in simultaneous pancreas-kidney transplant (SPKT) recipients that prevents acute rejection episodes (AREs) and allows optimal outcome remains elusive.

Methods

This cohort study assessed incidence and time to AREs in 73 consecutive SPKT recipients receiving alemtuzumab induction and steroid-free maintenance with tacrolimus and mycophenolate mofetil. A cohort with single high-dose antithymocyte globulin (ATG; n = 85) and triple therapy served as controls. In addition, we provided mechanistic insights in AREs after alemtuzumab depletion, including composition and alloreactivity of lymphocytes (flow cytometry and mixed lymphocyte reaction) plasma alemtuzumab levels (enzyme-linked immunosorbent assay), and maintenance drug exposure.

Results

Overall number of AREs at 3 years was significantly lower with alemtuzumab versus ATG induction (26.0% vs 43.5%; adjusted hazard ratio, 0.38; P = 0.029). Most AREs (94.6%) with ATG occurred within the first month, whereas 84.2% of AREs with alemtuzumab occurred beyond 3 months. Patients with and without an ARE in the steroid-free alemtuzumab group showed no differences in composition of lymphocytes, or in alemtuzumab levels. Of note, more than two thirds of these AREs were preceded by empiric tacrolimus and/or mycophenolate mofetil dose adjustments due to viral infections, leukopenia, or gastrointestinal symptoms.

Conclusions

Alemtuzumab induction resulted in a significant lower incidence of AREs. Empiric dose adjustments beyond 3 months in the absence of steroids carry a significant risk for subsequent rejection in SPKT recipients.

Randomized trial of rATg/Daclizumab vs. rATg/Alemtuzumab as dual induction therapy in renal transplantation: Results at 8years of follow-up

Our goal in using dual induction therapy is to bring the kidney transplant recipient closer (through more effectively timed lymphodepletion) to an optimally immunosuppressed state. Here, we report long-term results of a prospective randomized trial comparing (Group I,N=100) rATG/Dac (3 rATG, 2 Dac doses) vs. (Group II,N=100) rATG/Alemtuzumab(C1H) (1 dose each), using reduced tacrolimus dosing, EC-MPS, and early corticosteroid withdrawal. Lower EC-MPS dosing was targeted in Group II to avoid severe leukopenia. Median follow-up was 96mo post-transplant. There were no differences in 1st BPAR (including borderline) rates: 10/100 vs. 9/100 in Groups I and II during the first 12mo(P=0.54), and 20/100 vs. 20/100 throughout the study(P=0.90). Equally favorable renal function was maintained in both treatment arms(N.S.). While not significant, more patients in Group II experienced graft loss, 25/100 vs. 18/100 in Group I(P=0.23). Actuarial patient/graft survival at 96mo was 92%/83% vs. 85%/73% in Groups I and II(N.S.). DWFG-due-to-infection(N.S.), EC-MPS withholding-due-to-leukopenia during the first 2mo(P=0.03), and incidence of viral infections(P=0.09) were higher in Group II, whereas EC-MPS withholding-due-to-GI symptoms was higher in Group I(P=0.009). No other adverse event differences were observed. While long-term anti-rejection and renal function efficacy were demonstrated in both treatment arms, slight over-immunosuppression of Group II patients occurred.

Impact of Human Mutant TGFβ1/Fc Protein on Memory and Regulatory T Cell Homeostasis Following Lymphodepletion in Nonhuman Primates

Transforming growth factor β1 (TGFβ1) plays a key role in T cell homeostasis and peripheral tolerance. We evaluated the influence of a novel human mutant TGFβ1/Fc (human IgG4 Fc) fusion protein on memory CD4⁺ and CD8⁺ T cell (Tmem) responses in vitro and their recovery following antithymocyte globulin (ATG)-mediated lymphodepletion in monkeys. TGFβ1/Fc induced Smad2/3 protein phosphorylation in rhesus and human peripheral blood mononuclear cells and augmented the suppressive effect of rapamycin on rhesus Tmem proliferation after either alloactivation or anti-CD3/CD28 stimulation. In combination with IL-2, the incidence of CD4⁺ CD25^hi Foxp3^hi regulatory T cells (Treg) and Treg:Th17 ratios were increased. In lymphodepleted monkeys, whole blood trough levels of infused TGFβ1/Fc were maintained between 2 and 7 μg/mL for 35 days. Following ATG administration, total T cell numbers were reduced markedly. In those given TGFβ1/Fc infusion, CD8⁺ T cell recovery to predepletion levels was delayed compared to controls. Additionally, numbers of CD4⁺ CD25^hi CD127^lo Treg increased at 4-6 weeks after depletion but subsequently declined to predepletion levels by 12 weeks. In all monkeys, CD4⁺ CD25^hi Foxp3^hi Treg/CD4⁺ IL-17⁺ cell ratios were reduced, particularly after stopping TGFβ1/Fc infusion. Thus, human TGFβ1/Fc infusion may delay Tmem recovery following lymphodepletion in nonhuman primates. Combined (low-dose) IL-2 infusion may be required to improve the Treg:Th17 ratio following lymphodepletion.

Drug target molecules to guide immunosuppression

The individual and interindividual variability of response to immunosuppressants combined with the prevailing concept of lifelong immunosuppression following any organ transplantation motivates the search for methods to further individualize such therapy. Traditional therapeutic drug monitoring, adapting dose according to concentrations in blood, targets the pharmacokinetic variability. It has been increasingly recognized, however, that there is also a considerable variability in the response to a given concentration. Attempts to overcome this variability in response include the efforts to identify relevant targets and methods for pharmacodynamic monitoring. For several of the currently used immunosuppressants there is experimental data suggesting markers that are relevant as indicators for individual monitoring of the effects of these drugs. There are also some clinical data to support these approaches; however what is generally missing, are studies that in a prospective manner demonstrates the benefits and effects on outcome. The monitoring of antithymocyte globulin by lymphocyte subset counts is actually the only well established example of pharmacodynamic monitoring. For drugs such as MPA and mTOR inhibitors, there are candidates such as IMPDH activity expression and p70SK6 phosphorylation status, respectively. The monitoring of CNIs using assays for NFAT RGE, either alone or combined with concentration measurements, is already well documented. Even here, some further investigations relating to the categories of organ transplant, combination of immunosuppressants etc. will be requested. Although some further standardization of the assay is warranted and there is a need for specific recommendations of target levels and how to adjust dose, the NFAT RGE approach to pharmacodynamic monitoring of CNIs may be close to implementation in clinical routine.

Outcomes Associated with Steroid Avoidance and Alemtuzumab among Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

Alemtuzumab is a humanized anti-CD52 monoclonal antibody used as induction in kidney transplantation (KTX) since 2003. Few studies have evaluated long-term outcomes of this agent or changes in outcomes over time.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort study was performed examining United States registry data from 2003 to 2014 of primary KTX recipients receiving induction with alemtuzumab (AZ; n=5521) or antithymocyte globulin (ATG; n=8504) and maintenance immunosuppression with tacrolimus and mycophenolate mofetil and early withdrawal of steroids. The primary outcome was overall death-censored graft survival (DCGS), and secondary outcomes were overall patient survival and 1-year acute rejection. Multivariate models were fit with donor, recipient, and transplant covariates. Because poorer outcomes with AZ may occur from a learning curve impact with the use of a new medication, transplant year was categorized into three time periods to evaluate outcomes over time (2003-2005, 2006-2008, ≥2009), and an interaction term of induction type with transplant year category was included in all models to test for era impacts.

RESULTS

On multivariate analysis of DCGS there was a significant interaction between AZ and era (P<0.001). AZ was significantly associated with inferior DCGS in the earliest 2003-2005 era (adjusted hazard ratio [aHR], 2.21; 95% confidence interval [95% CI], 1.72 to 2.84) but not in the middle 2006-2008 era (aHR, 1.14; 95% CI, 0.96 to 1.36) or the most recent 2009-2014 era (aHR, 1.08; 95% CI, 0.90 to 1.29) compared with ATG. Risk-adjusted patient survival (aHR, 1.32; 95% CI, 1.08 to 1.61; aHR, 1.26; 95% CI, 1.09 to 1.46; and aHR, 1.10; 95% CI, 0.93 to 1.29 by era, respectively) and acute rejection (adjusted odds ratio [aOR], 1.17; 95% CI, 0.96 to 1.42; aOR, 0.94; 95% CI, 0.82 to 1.07; aOR, 0.89; 95% CI, 0.81 to 0.98 by era, respectively) with AZ was comparable with ATG in the most recent era; however, there was no significant interaction with time (P=0.13 and P=0.06, respectively).

CONCLUSIONS

Current alemtuzumab utilization is associated with comparable graft and patient survival and acute rejection compared with ATG. Graft survival with alemtuzumab has improved over time.

Lymphocytes as an Indicator for Initial Kidney Function: A Single Center Analysis of Outcome after Alemtuzumab or Basiliximab Induction

Alemtuzumab, an anti-CD52 T-cell and B-cell depleting monoclonal antibody, is established for induction therapy in renal transplantation (KTx). We herein provide a comparative analysis between alemtuzumab and basiliximab induction therapy and correlate lymphocyte depletion and recovery with the clinical course after KTx. This is a single center retrospective analysis of 225 patients/consecutive kidney transplantations treated with alemtuzumab for lymphocyte depletion and 205 recipients treated with basiliximab. Mean lymphocyte counts were 22.8 ± 9.41% before Tx and 2.61 ± 3.11% between week 1 and week 3 in the alemtuzumab group and 23.77 ± 10.42% before Tx and 13.92 ± 8.20% in the basiliximab group. Delayed graft function (DGF), cytomegalovirus (CMV) status, and recipient age showed a significant correlation with lymphocyte counts in the alemtuzumab group only. The outcome was read in reference to the velocity of lymphocyte recovery and in comparison to the control group. Lymphocyte counts early after transplantation, following alemtuzumab treatment, could be identified as a predictive factor for kidney function early after transplantation. A detailed analysis of phenotype and function of lymphocytes after alemtuzumab induction together with a correlation with the clinical course is warranted.

Rapidly growing non-tuberculous mycobacterial infection in a renal transplant patient after alemtuzumab induction

Renal transplant recipients are at high risk of developing opportunistic infections particularly in the first 6 months after transplantation. Organisms causing such infections include rapidly growing non-tuberculous mycobacteria (NTM). Lymphocytes have a central role in combating mycobacterial infections. The use of lymphocyte-depleting agents, such as alemtuzumab, in the renal transplant population has increased in recent years. A case of multifocal osteomyelitis caused by one of the NTM, Mycobacterium chelonae, in a renal transplant recipient, after alemtuzumab induction, is presented.

Characterization, prophylaxis, and treatment of infectious complications in craniomaxillofacial and upper extremity allotransplantation: a multicenter perspective

BACKGROUND

Vascularized composite allotransplants consist of heterogeneous tissues from different germ layers, which include skin, muscle, bone, fat, nerves, and lymph nodes. The antigenic diversity of these tissues, particularly of the highly immunogenic skin component, necessitates potent immunosuppressive regimens similar to that of some solid organ transplants. Indeed, the lifelong, high-dose, multidrug immunosuppressive protocols expose vascularized composite allotransplant recipients to considerable risk of infectious, metabolic, and neoplastic sequelae. In this article, the authors review the infectious risk to patients after vascularized composite allotransplantation, with special attention to the somewhat limited experience with the prophylaxis and treatment of infections after this innovative reconstructive surgery.

METHODS

A review of the literature was undertaken to elucidate the characterization, prophylaxis, and treatment of all documented infectious complications.

RESULTS

Infections in face and hand vascularized composite allotransplants follow a course similar to that of solid organ transplants. Several differences exist, including the unique flora of craniomaxillofacial transplants, the increased risk of donor-derived infections, and the alteration of the risk-to-benefit ratio for cytomegalovirus infections.

CONCLUSIONS

The patient with a face or limb transplant has many of the same infectious risks as a lung transplant recipient, which include bacterial, viral, and fungal infections. Because of the anatomy, mucosal exposure, and differing donor flora, however, the face or limb transplant is susceptible to invasive diseases from a variety of microbes.

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.

Alemtuzumab induction therapy in solid organ transplantation

Alemtuzumab (Campath) is a monoclonal antibody that has a profound lymphocyte-depleting effect, targeting the CD52 antigen that is present on all lymphocytes. Alemtuzumab has been used for the treatment of chronic lymphocytic leukaemia and various autoimmune disorders, and has also shown potential as an induction agent in the prevention of rejection following solid organ transplantation. Alemtuzumab has been studied in randomised controlled trials and has demonstrated low levels of rejection in renal transplant recipients compared with other induction agents, albeit mainly in the early months following transplantation. Studies have shown that alemtuzumab enables the use of lower calcineurin inhibitor (CNI) maintenance drugs; however, this reduction in nephrotoxic immunosuppression has not consistently been matched by an improvement in renal function. The hypothesis has been suggested that alemtuzumab might allow the development of immunosuppressive regimens that avoid CNIs completely; studies have investigated the combination of alemtuzumab with mammalian target of rapamycin-inhibitor maintenance therapy, and, in particular, sirolimus. Initial studies with this combination showed that regimens of sirolimus alone and of sirolimus with mycophenolate mofetil were unsuccessful, with a high rate of rejection and complications. Subsequent studies have targeted the combination of alemtuzumab induction with a short course of a CNI, before switching to maintenance therapy with sirolimus. This regimen might combine good protection from acute cellular rejection and chronic nephrotoxicity. A randomised controlled trial has been established to study this regimen, with results pending.

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.

Alemtuzumab induction therapy in kidney transplantation: a systematic review and meta-analysis

BACKGROUND

Alemtuzumab (MabCampath or Campath; Genzyme, Cambridge, MA) is a CD52-specific monoclonal antibody that causes profound and sustained lymphocyte depletion. Its use as an induction therapy in organ transplantation is increasing. Since our last systematic review in 2006, where we identified the need for good-quality randomized controlled trials (RCTs), several RCTs have been published that examine its efficacy and safety in kidney transplantation. The aim of this study was to evaluate the current evidence for alemtuzumab induction therapy in kidney transplantation.

METHODS

We performed a systematic literature search using Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Transplant Library from the Centre for Evidence in Transplantation, and International Clinical Trials Registry Platform. Inclusion criteria specified all RCTs in which kidney transplant recipients receiving induction with alemtuzumab were compared with those receiving another induction agent or no induction. Studies were assessed for methodological quality. The primary outcome was the incidence of biopsy-proven acute rejection (BPAR) (Banff grade ≥1), and secondary outcomes included graft loss, renal function, delayed graft function (DGF), patient death, and the incidence of infection, autoimmunity, malignancy, and new-onset diabetes mellitus after transplantation.

RESULTS

Ten RCTs, with a total of 1223 patients, were included. Studies were grouped according to induction regimens. Alemtuzumab induction has a lower risk of BPAR compared with induction with the interleukin-2 receptor antibodies (IL-2RAs): basiliximab (Simulect; Novartis, Basel, Switzerland) and daclizumab (Zenapax; Roche, Basel, Switzerland) combined (relative risk, 0.54; 95% confidence interval, 0.37-0.79; P<0.01). No significant difference was observed in the risk of BPAR when alemtuzumab induction was compared with rabbit antithymocyte globulin (rATG) (Thymoglobulin [Genzyme] or ATG-Fresenius S [Fresenius, Munich, Germany]) (relative risk, 0.79; 95% confidence interval, 0.52-1.21; P=0.28). There was no difference in graft loss, DGF, patient death, and new-onset diabetes mellitus after transplantation when alemtuzumab was compared with IL-2RAs or rATG induction. The effect of alemtuzumab induction on renal function and the incidence of infection, malignancy, and autoimmunity were limited by the data available. There were two trials comparing alemtuzumab with no induction, but neither trial reported a significant reduction in BPAR at 12 months.

CONCLUSIONS

Alemtuzumab induction reduces the risk of BPAR compared with IL-2RAs but not rATG. Because the incidence of other efficacy outcomes (graft loss, DGF, and patient death) was similar, if it is felt that an induction agent is necessary, then our analysis suggests that it is more acceptable to base the choice of induction agent on safety outcomes and/or costs.

Cancer risk with alemtuzumab following kidney transplantation

Alemtuzumab has been employed for induction therapy in kidney transplantation with low rates of acute rejection and excellent graft and patient survival. Antibody induction therapy has been linked to increased vulnerability to cancer. Data regarding malignancy rates with alemtuzumab are limited. We studied 1350 kidney transplant recipients (between 2001 and 2009) at the University of Pittsburgh Starzl Transplant Institute, for post-transplant de novo and recurrent malignancy, excluding non-melanoma skin cancer, among patients receiving alemtuzumab, thymoglobulin, and no induction therapies. Of the 1350 patients, 1002 (74.2%) received alemtuzumab, 205 (15.2%) received thymoglobulin, and 122 (9%) received no induction therapy. After excluding cancers occurring within 60 d post-transplantation, 43 (3.25%) malignancies were observed during a median follow-up time of 4.0 yr. The incidence of malignancy was 5.4% (1.09 per 100 patient-years [PY]) with thymoglobulin, 2.8% (0.74 per 100 PY) with alemtuzumab, and 3.3% (0.66 per 100 PY) with no induction (across all groups; p = 0.2342, thymoglobulin vs. alemtuzumab; p = 0.008). Thus, with the exception of non-melanoma skin cancer which we did not evaluate, alemtuzumab induction was not associated with increased cancer incidence post-kidney transplantation when compared to no induction therapy and was associated with lower cancer incidence when compared to thymoglobulin.

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.

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.

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.

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.

Review of cytomegalovirus infection findings with mammalian target of rapamycin inhibitor-based immunosuppressive therapy in de novo renal transplant recipients

Cytomegalovirus (CMV) infection and disease are major complications in the renal transplant recipient. The occurrence of CMV is associated with acute rejection, allograft dysfunction, significant end-organ disease, and mortality. Several clinical studies have indicated that the use of certain immunosuppressive drugs can delay the reconstitution of CMV-specific cell-mediated immune responses, thereby leading to uncontrolled CMV replication. Accumulating evidence indicates, however, that the use of the mammalian target of rapamycin (mTOR) inhibitors, sirolimus, and everolimus, may decrease the incidence and severity of CMV infection in renal transplant recipients. The purpose of this article is to review CMV infection data from randomized clinical trials that investigated the use of sirolimus- and everolimus-based treatment regimens in de novo renal transplantation. The mTOR inhibitor clinical trials included were primarily identified using biomedical literature database searches, with additional studies added at the authors' discretion. This review will summarize these studies to discuss whether mTOR inhibitor-based immunosuppressive therapy can reduce the magnitude of CMV-related complications in the de novo renal transplantation setting.

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.

Use of monoclonal antibodies in renal transplantation

Monoclonal antibodies are applied in various settings in renal transplantation. Depleting T-cell antibodies are used for treatment of steroid-resistant acute rejection and as induction therapy to reduce the intensity of concomitant immunosuppressive drug therapy. Induction therapy with the nondepleting IL-2 receptor antagonists basiliximab and daclizumab, added to cyclosporine-based regimens, reduces the incidence of acute rejection without side effects. However, an increase in long-term graft and patient survival has not been demonstrated yet. The B-cell-targeting antibody rituximab is used in blood group ABO-incompatible transplantation, in desensitization protocols, and for treatment of antibody-mediated rejection. Eculizumab interrupts the complement pathway and is a promising tool for the treatment of antibody-mediated rejection and post-transplant hemolytic-uremic syndrome. Future options are monoclonal antibodies with new molecular targets and antibodies that can be used for maintenance immunosuppression in order to avoid the toxicity of existing drugs. However, in several cases, the development of new monoclonal antibodies has been hampered by safety issues.

Alemtuzumab induction in deceased donor kidney transplantation

PURPOSE

Alemtuzumab (Campath-1H), a humanized monoclonal antibody directed against CD52, is a lymphocyte-depleting agent currently being evaluated as an induction agent in solid organ transplantation. This study analyzed the clinical outcomes and effects on peripheral blood lymphocyte subset counts in adult deceased donor renal transplant recipients who received an alemtuzumab-based induction protocol.

METHODS

Eleven kidney alone or simultaneous pancreas-kidney transplant recipients received 20 mg alemtuzumab on postoperative days 0 and 1, followed by calcineurin inhibitor-based maintenance immunosuppression after postoperative day 5. We collected 1-year data including recipient and donor demographic features, renal function and adverse events including endocrine impact, incidence of acute rejection episodes, infections or malignancies as well as hematologic and late immunologic parameters for correlation with patient or graft survival.

RESULTS

Mean HLA mismatch was 3.6 and 8/11 deceased donors were of the extended criteria type. Only 2 (18%) recipients displayed delayed graft function with a failure of the serum creatinine to decrease by 25% on the first day; however, their long-term outcomes were similar to other nonaffected patients. Serious adverse events were absent; there was no hyperlipidemia or new-onset diabetes. We failed to observe an acute rejection. The 3 (27%) recipients with infectious complications experienced pericardial tuberculosis, urinary tract infection, or invasive pulmonary aspergillosis. Two (18%) cases of posttransplantation lymphoproliferative disease were diagnosed in this study during the follow-up. Overall patient and graft survival rates were both 91%.

CONCLUSION

This study demonstrated that preconditioning with antibody-depletion using alemtuzumab was efficient with satisfactory patient and graft survivals at 1 year. Alemtuzumab induction was safe even for recipients of extended criteria donor renal transplantation.

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.