Induction Antibody Therapy in Kidney Transplantation

The impact of induction therapy in low-immunological risk kidney transplant recipients regardless of HLA matching

BACKGROUND

Induction agents have proved to reduce the rate of acute rejection (AR) in kidney transplant recipients (KTRs) without improving long-term graft and patient survival (PS).

OBJECTIVE

This study evaluates the utility of induction therapy in low immunological risk KTRs regardless of donor-to-recipient HLA matching.

METHODS

We retrospectively reviewed the records of 218 patients undergoing kidney transplantation (KT). These patients were divided into two groups according to the usage of induction therapy: 82 did not receive any induction therapy (Group I), and 136 patients received either Anti-IL2 receptor antibodies or anti-thymocyte globulin (Group II). All patients had panel reactive antibody (PRA) < 20% and absence of donor-specific antibodies (DSA). The difference in outcomes were assessed at different intervals following KT.

RESULTS

The rate of bacterial infections at one year (p-value = 0.032) and the frequency of CMV disease (p-value = 0.044) were significantly higher in Group II (with induction therapy). The duration of hospital stay, the rate and severity of acute rejection, the occurrence of delayed graft function, the rate and type of surgical complications at one year, and the graft function and survival at one and three years were similar between the two groups (p-value = NS). In addition, the financial burden is much less in Group I (without induction therapy), reducing the total cost of the transplant procedure.

CONCLUSION

We conclude that induction therapy in low-immunological risk kidney transplant patients is not a must regardless of donor-to-recipient HLA matching. Therefore, induction therapy did not yield significant health results, but had negative financial consequences.

Comparison of Thymoglobulin and Grafalon as Induction Agents in Renal Transplantation: A Prospective Study

BACKGROUND

Induction immunosuppression is used to reduce the incidence of acute rejection and prevent delayed graft function. The 2 rabbit anti-thymocyte globulins- thymoglobulin and Grafalon (ATG Fresenius) have been commonly used for induction immunosuppression and treatment of acute rejection in solid organ transplantation. There are very few studies comparing the efficacy and side effects of both the anti-thymocyte globulins therefore this prospective study comparing the 2 types of anti-thymocyte globulins would be of clinical interest.

PATIENTS AND METHODS

This prospective single center study was conducted at Rabindranath Tagore International Institute of Cardiac Sciences, Kolkata, India from April 2019 to June 2020. Sixty-two ABO-compatible renal transplant recipients were included in the study. They were divided in 2 groups of 31 patients each. One group received thymoglobulin (3 mg/kg) and the second group received Grafalon (6 mg/kg). All patients were followed up for 12 months and the 2 groups were compared for incidence of rejections, infections, graft function, patient survival, and graft survival.

RESULTS

There was no significant difference in the incidence of rejections, infective episodes, graft function, posttransplant diabetes mellitus, graft survival and patient survival in thymoglobulin or Grafalon groups. The hematological parameters were similar in both groups at 7 days, 1 month, and 6 months of follow-up. The absolute lymphocyte count was significantly lower in the thymoglobulin group at 12 months posttransplant.

CONCLUSIONS

Thymoglobulin and Grafalon were found to be equivalent in terms of safety and efficacy in short term, with no difference in rejections, infections, graft survival, or patient survival.

Anti-T-Lymphocyte Immunoglobulin (Grafalon) as an Induction Agent for Renal Transplantation: A Real-World, Retrospective, Single-Center Experience

OBJECTIVES

Polyclonal antithymocyte globulins are widely used in the induction regimens of solid-organ transplant recipients; however, their doses and outcomes remain to be standardized in Indian patients. We report our clinical experience from the real-world use of Grafalon (an anti-T-lymphocyte globulin; ATG-Fresenius) as an induction agentin renal transplant recipients from India.

MATERIALS AND METHODS

In this retrospective, single- center, observational study, we analyzed the medical records of 177 consecutive, kidney-only transplant recipients who received induction therapy with Grafalon from September 2016 to March 2018 at our center. Incidences of biopsy-proven acute rejection and graft dysfunction, immunosuppression protocol, Grafalon dosage, 18-month post-transplant graft and patient survival, treatment-related adverse events, and infective complications were reported.

RESULTS

Mean age of patients was 41.46 years (range, 14-68 years), (85% were males). The average dose of Grafalon was 5.81 ± 1.95 mg/kg (range, 2.41 to 10.07 mg/kg). Graft dysfunction (ie, at least 20% increase in serum creatinine from baseline) was observed in 26 patients (14%): 11 patients (6.2%) had biopsy-proven acute rejections, 11 patients (6.2%) had acute tubular necrosis, and 4 patients (2.2%) had calcineurin inhibitor toxicity. Seven deaths were recorded: 2 each from fungal pneumonia, bacterial pneumonia, and acute coronary syndrome and 1 with urinary tract infection with septicemia. Death-censored graft survival was 100% at 12 months and 98% at 18-month follow-up; overall patient survival was 96%. Infective complications occurred in 40 patients (22.5%), with the most common being urinary tract infection in 32 patients (18%). No malignancies were reported.

CONCLUSIONS

Use of a potent induction therapy like anti-T-lymphocyte globulin (Grafalon) is often restricted by the risk of side effects and lack of local clinical evidence supporting its role in long-term graft survival. Real-world evidence support the safe and effective use of anti-T-lymphocyte globulin as an induction agent in renal transplant recipients with an individualized dosing approach.

A Randomized Prospective Study Comparing Anti-T-Lymphocyte Igs to Basiliximab in Highly Sensitized Kidney Transplant Patients

Background

Two prospective studies that were performed before the era of highly sensitive solid-phase assays have shown a lower incidence of acute rejection in highly sensitized kidney-transplant patients given polyclonal antibodies compared with those given anti-CD25 monoclonal antibodies.

Methods

This prospective pilot randomized French multicenter study aimed to compare anti–T-lymphocyte Ig (ATLG) (n = 32) and basiliximab (n = 27) in highly sensitized kidney-transplant patients without preformed donor-specific antibodies (pDSAs) as assessed by a Luminex Single-Antigen flow bead assay. Only patients with a calculated panel reactive antibody ≥50%, with at least 1 antibody with a mean fluorescence intensity ≥5000 and without a historical pDSA and without a pDSA on the day of transplantation were included.

Results

Treatment failure as defined by biopsy-proven acute rejection, patient lost to follow-up, graft loss, and death was observed in 18.8% (95% confidence interval [CI], 8.9%–37.1%) and 18.8% (95% CI, 8.9%–37.1%) in patients who received ATLG and 14.8% (95% CI, 5.8%–34.8%) and 28.2% (95% CI, 14.2%–51.2%) of patients who received basiliximab, respectively at 6 (P = 0.66) and 12 (P = 0.62) months post-transplantation. One T cell–mediated rejection was observed in ATLG-treated patients (3.1%). One antibody-mediated rejection due to a de novo donor-specific antibody (DSA) occurred in basiliximab-treated patients (3.7%). Patient survival, graft survival, kidney parameters, and infection rate were similar in the 2 groups.

Conclusion

This pilot study indicates that in highly sensitized kidney-transplant patients without pDSAs, both ATLG and basiliximab can be used efficiently and safely. However, because of the lack of power, these results should be interpreted with caution.

Thymoglobulin vs. ATG-Fresenius as Induction Therapy in Kidney Transplantation: A Bayesian Network Meta-Analysis of Randomized Controlled Trials

Background: Thymoglobulin (THG) and antithymocyte globulin-Fresenius (ATG-F) have not been compared directly as induction therapies in kidney transplantation. Materials and Methods: We performed a Bayesian network meta-analysis to compare THG with ATG-F by pooling direct and indirect evidence. Surface under the cumulative ranking curve (SUCRA) values were used to compare the superiority of one method over the other. Results: A total of 27 randomized controlled trials (RCT) were eligible for the network meta-analysis. Efficacy endpoints, as well as safety indicators, were statistically comparable. For efficacy endpoints, THG seemed inferior to ATG-F in preventing delayed graft function [odds ratio (OR): 1.27; SUCRA: 78% vs. 58%], patient deaths (OR: 2.78; SUCRA: 83% vs. 34%), and graft loss (OR: 1.40; SUCRA: 83% vs. 59%), but superior to ATG-F in biopsy-proven acute rejection (BPAR; OR: 0.59; SUCRA: 78% vs. 39%) and steroid-resistant BPAR prevention (OR: 0.61; SUCRA: 76% vs. 49%) within the first year. For safety endpoints, THG was associated with higher risk of infection (OR: 1.49, SUCRA: 79% vs. 54%), cytomegalovirus infection (OR: 1.04; SUCRA: 40% vs. 37%), de novo diabetes (OR: 1.10; SUCRA: 90% vs. 30%), and malignancy (OR: 8.40; SUCRA: 89% vs. 6%) compared to ATG-F. A subgroup analysis of patients at high risk for immunologic complications revealed similar results, but THG performed better for graft loss (OR: 0.82; SUCRA: 68% vs. 54%). Conclusion: ATG-F seemed to be more effective than THG in improving the short-term kidney transplantation outcomes. Prospective head-to-head comparison of THG and ATG-F with larger sample sizes and longer follow-up is still required.

Induction Therapy With ATG Compared With Anti-IL2 Basiliximab in Low-Immunologic Risk Kidney Transplant Recipients

Practically all kidney allograft recipients require immunosuppressive therapy to prevent rejection and loss of the allograft. The aim of this study was to determine the occurrence of biopsy-proven acute rejection in low-immunologic risk kidney transplant recipients according to the type of induction (basiliximab vs low-dose of rabbit antithymocyte globulin [rATG], 3.5 mg/kg).

MATERIALS AND METHODS

A total of 125 patients after primary kidney transplant were included in the retrospective analysis with 6-month follow-up. The immunosuppression regimen included tacrolimus, mycophenolic acid, and corticoids.

RESULTS

We did not find any significant difference in the occurrence of acute rejection or difference in the occurrence of infection complications. Patients in the rATG group had a significantly longer period of cold ischemia, more frequently received kidney transplants from expanded criteria donors, and had significantly more mismatches in HLA-DR. Delayed graft function (DGF) was identified as an independent risk factor for biopsy-proven acute rejection (hazard ratio, 3.4859; P = .003). There was comparable incidence of DGF between the 2 groups despite that there were several factors that are more commonly associated with DGF in the rATG group.

CONCLUSION

Patients with low immunologic risk and high risk of DGF benefit from the rATG induction in dose of 3.5 mg/kg without the increased risk of infection complications with the assumption of good graft function in long-term post-transplant period.

Polyclonal anti T-lymphocyte antibody therapy monitoring in kidney transplant recipients: comparison of CD3+ T cell and total lymphocyte counts

Objective:

To investigate the correlation between total lymphocyte and CD3⁺ T cell counts in peripheral blood in renal transplant patients treated with anti-thymocyte globulin, and discuss related outcomes.

Methods:

A single-center, retrospective study involving 226 patients submitted to kidney transplant between 2008 and 2013, and treated with anti-thymocyte globulin for induction or treatment of cellular rejection. Doses were adjusted according to CD3⁺ T cell or total lymphocyte counts in peripheral blood.

Results:

A total of 664 paired samples were analyzed. The Spearman's correlation coefficient was 0.416 (p<0.001) for all samples combined; the overall Kappa coefficient was 0.267 (p<0.001). Diagnostic parameters estimated based on total lymphocyte counts were also calculated using the number of CD3⁺ T cells (gold standard), with a cut off of >20 cells/mm³.

Conclusion:

Total lymphocyte and CD3⁺ T cell counts in peripheral blood are not equivalent monitoring strategies in anti-thymocyte globulin therapy.

Efficacy and safety of antibody induction therapy in the current era of kidney transplantation

BACKGROUND

Antibody induction with polyclonal rabbit-antithymocyte globulin (rATG) or an interleukin-2 receptor antagonist (IL-2RA) is widely used in kidney transplantation.

METHODS

Collaborative Transplant Study data from 38 311 first deceased-donor kidney transplants (2004-13) were analysed. Transplants were classified as 'normal risk' or 'increased risk' according to current guidelines. Cox regression analysis was applied to subpopulations of propensity score-matched recipients.

RESULTS

rATG or IL-2RA induction was given to 64% of increased-risk and 53% of normal-risk patients, respectively. rATG and IL-2RA induction were each associated with reduced risk for graft loss versus no induction in increased-risk patients [hazard ratio (HR) 0.85, P = 0.046 and HR 0.89, P = 0.011, respectively]. The HR values for incidence of treated rejection in increased-risk patients for rATG and IL-2RA versus no induction were 0.75 (P = 0.037) and 0.77 (P < 0.001), respectively. In the normal risk subpopulation, neither induction therapy significantly affected the risk of graft loss or treated rejection. Hospitalization for infection was increased by rATG (P < 0.001) and IL-2RA (P < 0.001) induction. In contrast to patients transplanted during 1994-2003, among patients transplanted during 2004-13, rATG did not significantly affect the risk of non-Hodgkin's lymphoma versus no induction (P = 0.68).

CONCLUSION

Induction therapy following kidney transplantation should be targeted to increased-risk transplants. In this analysis, a beneficial effect of antibody induction in normal-risk transplants could not be demonstrated.

Comparison of efficacy and safety between rabbit anti-thymocyte globulin and anti-T lymphocyte globulin in kidney transplantation from donation after cardiac death: a retrospective cohort study

AIM

To compare the efficacy and safety between rabbit anti-thymocyte globulin (Thymoglobulin) and anti-T lymphocyte globulin (ATG-Fresenius, ATG-F) in donation after cardiac death (DCD) kidney transplantation.

METHODS

We retrospectively analyzed 255 cases of DCD kidney transplantation performed at our hospital from February 2007 to October 2013. The patients were divided into two groups based on their induction therapies with Thymoglobulin (n = 188) or ATG-F (n = 67). Clinical data were collected and compared between the two groups.

RESULTS

Delayed graft function (DGF) occurred in 36 (19.1%) patients in the Thymoglobulin group versus 17 (25.4%) patients in the ATG-F group (P = 0.281). However, if we subgroup the patients with increased risk factors for DGF, the DGF rate was 9/40 (22.5%) in the Thymoglobulin group versus 9/16 (56.3%) in the ATG-F group (P = 0.015). Duration of DGF was significantly shorter in the Thymoglobulin group (11.7 days vs. 16.1 days). The acute rejection rate was significantly lower in the Thymoglobulin group (9.6% vs. 19.4%, P = 0.035). One-year graft and patient survival were both comparable between the Thymoglobulin and ATG-F groups. The adjusted odds ratio of DGF was 4.283 (1.137-16.13) between the ATG-F and Thymoglobulin groups in patients with increased risk factors for DGF.

CONCLUSION

Compared with ATG-F, Thymoglobulin may reduce duration of DGF and acute rejection rate after DCD kidney transplantation. Moreover, Thymoglobulin significantly reduced DGF in patients with increased risk factors for DGF.

Predictive model for delayed graft function based on easily available pre-renal transplant variables

Identification of pre-transplant factors influencing delayed graft function (DGF) could have an important clinical impact. This could allow clinicians to early identify dialyzed chronic kidney disease (CKD) patients eligible for special transplant programs, preventive therapeutic strategies and specific post-transplant immunosuppressive treatments. To achieve these objectives, we retrospectively analyzed main demographic and clinical features, follow-up events and outcomes registered in a large dedicated dataset including 2,755 patients compiled collaboratively by four Italian renal/transplant units. The years of transplant ranged from 1984 to 2012. Statistical analysis clearly demonstrated that some recipients' characteristics at the time of transplantation (age and body weight) and dialysis-related variables (modality and duration) were significantly associated with DGF development (p ≤ 0.001). The area under the receiver-operating characteristic (ROC) curve of the final model based on the four identified variables predicting DGF was 0.63 (95 % CI 0.61, 0.65). Additionally, deciles of the score were significantly associated with the incidence of DGF (p value for trend <0.001). Therefore, in conclusion, in our study we identified a pre-operative predictive model for DGF, based on inexpensive and easily available variables, potentially useful in routine clinical practice in most of the Italian and European dialysis units.

Karyopherins: potential biological elements involved in the delayed graft function in renal transplant recipients

Background

Immediately after renal transplantation, patients experience rapid and significant improvement of their clinical conditions and undergo considerable systemic and cellular modifications. However, some patients present a slow recovery of the renal function commonly defined as delayed graft function (DGF). Although clinically well characterized, the molecular mechanisms underlying this condition are not totally defined, thus, we are currently missing specific clinical markers to predict and to make early diagnosis of this event.

Methods

We investigated, using a pathway analysis approach, the transcriptomic profile of peripheral blood mononuclear cells (PBMC) from renal transplant recipients with DGF and with early graft function (EGF), before (T0) and 24 hours (T24) after transplantation.

Results

Bioinformatics/statistical analysis showed that 15 pathways (8 up-regulated and 7 down-regulated) and 11 pathways (5 up-regulated and 6 down-regulated) were able to identify DGF patients at T0 and T24, respectively. Interestingly, the most up-regulated pathway at both time points was NLS-bearing substrate import into nucleus, which includes genes encoding for several subtypes of karyopherins, a group of proteins involved in nucleocytoplasmic transport. Signal transducers and activators of transcription (STAT) utilize karyopherins-alpha (KPNA) for their passage from cytoplasm into the nucleus. In vitro functional analysis demonstrated that in PBMCs of DGF patients, there was a significant KPNA-mediated nuclear translocation of the phosphorylated form of STAT3 (pSTAT3) after short-time stimulation (2 and 5 minutes) with interleukin-6.

Conclusions

Our study suggests the involvement, immediately before transplantation, of karyopherin-mediated nuclear transport in the onset and development of DGF. Additionally, it reveals that karyopherins could be good candidates as potential DGF predictive clinical biomarkers and targets for pharmacological interventions in renal transplantation. However, because of the low number of patients analyzed and some methodological limitations, additional studies are needed to validate and to better address these points.

Central memory CD8+ T lymphocytes mediate lung allograft acceptance

Memory T lymphocytes are commonly viewed as a major barrier for long-term survival of organ allografts and are thought to accelerate rejection responses due to their rapid infiltration into allografts, low threshold for activation, and ability to produce inflammatory mediators. Because memory T cells are usually associated with rejection, preclinical protocols have been developed to target this population in transplant recipients. Here, using a murine model, we found that costimulatory blockade-mediated lung allograft acceptance depended on the rapid infiltration of the graft by central memory CD8+ T cells (CD44(hi)CD62L(hi)CCR7+). Chemokine receptor signaling and alloantigen recognition were required for trafficking of these memory T cells to lung allografts. Intravital 2-photon imaging revealed that CCR7 expression on CD8+ T cells was critical for formation of stable synapses with antigen-presenting cells, resulting in IFN-γ production, which induced NO and downregulated alloimmune responses. Thus, we describe a critical role for CD8+ central memory T cells in lung allograft acceptance and highlight the need for tailored approaches for tolerance induction in the lung.

A review on comparing two commonly used rabbit anti-thymocyte globulins as induction therapy in solid organ transplantation

INTRODUCTION

Two rabbit anti-thymocyte globulins (ATGs) (Thymoglobulin™ and ATG-Fresenius (ATG-F)™) have been used commonly for induction immunosuppression and treatment of acute rejection in solid organ transplantation. Therefore, literature review on comparative efficacy and side-effect profile of them would be of clinical interest.

AREAS COVERED

This review evaluated all comparative studies in English language, focusing on the solid organ transplant patients who received Thymoglobulin or ATG-F as induction therapy. This review concluded that compared to ATG-F, Thymoglobulin possibly provides better protection against acute rejection and improves patient and graft survival but may result in more cytomegalovirus infection and post-transplant malignancy. Thymoglobulin produced more leukocyte depletion with a greater delay to recover, while ATG-F had more reduction effects on platelet and erythrocyte counts with an increased need to erythropoiesis-stimulating agent.

EXPERT OPINION

The benefits of induction therapy with ATGs must be weighed against the costs and post-transplant complications. It is suggest that there is no substantial clinical difference between these two rabbit ATGs and each may be considered as induction therapy for solid organ transplantation based on availability and drug cost. Of special importance is adding antiviral therapy to the treatment regimen of patients who receive ATGs as induction therapy.

Impact of anti-T-cell therapy in the immunogenicity of seasonal influenza vaccine in kidney transplant recipients

BACKGROUND

The influence of anti-T-cell therapy in the immunogenicity of the influenza vaccine in kidney transplant recipients remains unclear.

METHODS

During the 2010 to 2011 influenza season, we evaluated the immune response to the inactivated trivalent influenza vaccine in kidney transplant recipients having received Thymoglobulin or basiliximab as induction therapy. A hemagglutination inhibition assay was used to assess the immunogenicity of the vaccine. The primary outcome was geometric mean titers of hemagglutination inhibition after influenza vaccination.

RESULTS

Sixty patients (Thymoglobulin n=22 and basiliximab n=38) were included. Patients in the Thymoglobulin group were older (P=0.16), showed higher creatinine levels (P=0.16) and had more frequently received a previous transplant (P=0.02). There were no significant differences in geometric mean titers for any of the three viral strains between groups (P=0.69 for H1N1, P=0.56 for H3N2, and P=0.7 for B strain). Seroconversion to at least one viral strain was seen in 15 (68%) of 22 patients in the Thymoglobulin group and 28 (73%) of 38 in the basiliximab group (P=0.77). In patients vaccinated during the first year after receiving anti-T-cell therapy (n=25), there was a trend toward lower vaccine responses in the Thymoglobulin group. Patients who received Thymoglobulin showed lower CD4(+) cell counts and lower levels of IgM, at an average of 16.2 months after transplantation. A multivariate analysis showed that only the absence of mycophenolate was associated with a better vaccine response (odds ratio=9.47; 95% confidence interval, 1.03-86.9; P=0.047).

CONCLUSION

No significant differences were seen in immunogenicity of the influenza vaccine in kidney transplant recipients having received either Thymoglobulin or basiliximab.

The implications of acute rejection for allograft survival in contemporary U.S. kidney transplantation

BACKGROUND

We examined the frequency and clinical impact of acute rejection (AR) in contemporary U.S. kidney transplantation.

METHODS

Data for Medicare-insured kidney transplant recipients in 2000 to 2007 (n=48,179) were drawn from the United States Renal Data System. AR events were ascertained from Organ Procurement and Transplantation Network reports. AR was subclassified as antibody (Ab)-treated AR or other management (non-Ab-treated AR). Associations of AR with subsequent all-cause graft loss were estimated with time-varying Cox regression. Covariates included recipient, donor, and transplant factors in the United Network for Organ Sharing Kidney Allocation Review Committee survival model.

RESULTS

The frequencies of non-Ab-treated AR per 100 graft-years at risk among standard criteria donor recipients over the first 6, 12, 24, and 36 months after transplantation were 9.93, 8.43, 5.71, and 4.70, respectively. Non-Ab-treated AR was consistently more than twice as common as Ab-treated AR by risk period and donor type. Development of Ab-treated AR predicted a greater risk of graft loss than non-Ab-treated AR. The relative risk for graft loss from Ab-treated AR continuously increased with later timing of AR after transplantation, whereas risk associated with non-Ab-treated AR peaked for events reported in months 13 to 24 after kidney transplantation. Regardless of the diagnosis time, the relative risk of graft loss was higher in the first 89 days after a given AR report compared with 90 days and beyond.

CONCLUSIONS

AR events recognized later after transplantation have more serious graft loss implications, especially within the first 89 days after AR reporting. This observation may reflect reduced intensity of monitoring, delays in diagnosis, or clinicopathologic features of late AR.

Alemtuzumab induction in renal transplantation: a meta-analysis and systemic review

OBJECTIVE

To compare the efficacy and safety of alemtuzumab versus traditional antibodies for induction therapy in renal transplantation.

METHODS

Literature searches for all randomized controlled trials comparing alemtuzumab with traditional antibodies for post renal transplant induction therapy were performed using MEDLINE, EMBASE and the Cochrane Library. Quality assessment was performed in each trial. Meta-analyses were performed to demonstrate the pooled effects of relative risk (RR) with 95% confidence intervals (CI).

RESULTS

A total of 808 participants from six randomized controlled trials (RCTs) were included. Alemtuzumab was associated with lower incidence of biopsy-proven acute rejection over traditional antibodies (RR 0.63, CI 0.45-0.87, p=0.005). This difference remained when only studies comparing alemtuzumab with rabbit antithymocyte globulin were included (RR 0.32, CI 0.11-0.91, p=0.03), but lost significance when only patients at high-risk were included (RR 0.86, CI 0.48-1.55, p=0.62). No significant differences were detected between alemtuzumab and traditional antibodies in terms of delayed graft function, patient death, graft loss, and safety profile.

CONCLUSIONS

Alemtuzumab induction is superior to traditional antibodies in preventing AR in renal transplantation, but this benefit may not extend to recipients at high immunologic risk. The lower rejection rates do not translate into a uniform increase in graft or patient survival.

Routine induction therapy in living donor liver transplantation prevents rejection but may promote recurrence of hepatitis C

BACKGROUND

Routine induction therapy in living donor liver transplantation (LDLT) has not been well described.

METHODS

We reviewed outcomes of induction therapy with rabbit antithymocyte globulin (rATG) or basiliximab within 1 year of LDLT.

RESULTS

Between 2002 and 2007, 184 adults underwent LDLT and received induction therapy in addition to standard immunosuppression. Acute cellular rejection (ACR) developed in 17 of 130 patients (13.1%) who received rATG and 13 of 54 patients (24.1%) who received basiliximab (P = .066). The interval between transplantation and rejection as well as rejection severity was similar in patients who received rATG and those who received basiliximab. Hepatitis C (HCV) recurrence requiring initiation of antiviral therapy was more common in patients who received rATG compared with basiliximab (34.5% vs 8.7%; P = .021), and in those who received induction combined with tacrolimus as opposed to cyclosporine (38.5% vs 3.9%; P = .001). rATG and basiliximab were associated with excellent patient and graft survivals well as low rates of opportunistic infections and malignancies.

CONCLUSION

Induction with rATG or basiliximab was well tolerated and highly effective at preventing ACR within 1 year of LDLT, but may be associated with a higher risk of clinically significant HCV recurrence in some patients.

A CD3+ count-based thymoglobulin induction regimen permits delayed introduction of calcineurin inhibitors in kidney transplantation

BACKGROUND

Withholding calcineurin inhibitors (CNIs) can be considered when graft function is inadequate following kidney transplantation (KT). Thymoglobulin (rATG) can be used to prevent acute rejection while CNIs are being withheld. Here, we report our results of a novel CNI-sparing induction protocol, which utilizes a CD3+ cell count-based rATG treatment regimen when delayed graft function (DGF) develops in the immediate postoperative period.

METHODS

In a cohort of 153 consecutive deceased-donor KT recipients, all received a single intraoperative dose of basiliximab; 84 subsequently developed DGF and therefore received rATG (rATG+ group), while 69 demonstrated immediate graft function and received CNIs (rATG- group).

RESULTS

In the rATG+ group, mean duration of therapy was 8.5±6.0 d, permitting CNI initiation to be delayed until postoperative day 10.3±6.2. Cumulative dose of rATG was only 5.1±4.5 mg/kg while targeting CD3+ counts of ≤30 cells/mm3. CD3+ counts were reduced to a mean of 16.7±17.0 cells/mm3 during therapy. At one yr, patient and graft survival rates were 97.6% and 92.9%, respectively, while the frequency of infections and malignancies were not significantly increased compared to the rATG- group.

CONCLUSION

A unique induction regimen successfully delayed CNI initiation by using modest doses of rATG to deplete CD3+ cells, while yielding excellent long-term graft outcome without increased risk of infection or malignancy.

A randomized trial with steroids and antithymocyte globulins comparing cyclosporine/azathioprine versus tacrolimus/mycophenolate mofetil (CATM2) in renal transplantation

BACKGROUND

The best immunosuppressive regimen in benefit-risk ratio in renal transplantation is debated. Nowadays, tacrolimus (Tac) and mycophenolate mofetil (MMF) are considered more efficient than cyclosporine A (CsA) and MMF, but recent studies have challenged this assumption.

METHODS

We conducted a monocentric, prospective, open-labeled, randomized, and controlled trial comparing CsA/azathioprine (Aza) versus Tac/MMF in 289 kidney transplant recipients treated with antithymocyte globulins and prednisone. Primary outcome was the number of patients with clinically suspected acute rejection at 1 year. Secondary outcomes were the number of patients with biopsy-proven acute rejection (BPAR), estimated glomerular filtration rate (eGFR), patient and graft survivals, and adverse events at 1 and 3 years.

RESULTS

During the first year, 21 patients had clinically suspected acute rejection with CsA/Aza (14.4%) vs. 11 (7.7%) with Tac/MMF (P=0.07). BPAR, including borderline, was more frequent in the CsA/Aza group (14.4%) than in the Tac/MMF group (5.6%; P=0.013). At 1 year, patient and graft survivals were not different, and eGFR was 48±1 in the CsA/Aza group and 53±1 mL/min/1.73 m in the Tac/MMF group (P=0.007). There was no significant difference in diabetes after transplantation (16.8% and 18.8%, respectively).

CONCLUSIONS

With antithymocyte globulins and steroids, clinically suspected acute rejections did not differ between CsA/Aza and Tac/MMF arms. Analysis of secondary endpoints showed a lower rate of BPAR, including border line, and a higher eGFR in the Tac/MMF group. CsA/Aza allowed a low acute rejection rate, but Tac/MMF seemed as a better regimen regarding severe secondary outcomes.

The effect of low and ultra-low dosages Thymoglobulin on peripheral T, B and NK cells in kidney transplant recipients

INTRODUCTION

Rabbit Anti-Thymocyte Globulin (r-ATG) is a polyclonal antibody preparation, used to prevent and treat acute rejection episodes after organ transplantation. However, despite more than 40 years of clinical use, the optimal dose of r-ATG is still not defined. To find a better balance between efficacy and infectious complications, we embarked on a controlled study and monitored the effect of low and ultra-low dosages Thymoglobulin (Genzyme) on peripheral T, B, and NK cells.

PATIENTS AND METHODS

Kidney transplant recipients received either 0.5 mg/kg, 1.0 mg/kg or 2.0 mg/kg on the first 3 consecutive days post-transplantation. Thus, total doses were 1.5 mg/kg, 3.0 mg/kg and 6.0 mg/kg. A total of 40 patients were enrolled, including 11 controls. All patients were treated with Prednisolon, Advagraf (Astellas) and Mycophenolate Mofetil (Roche). T (CD3+), B (CD19+) and NK (CD3-CD16+56+) cells were analyzed by flow cytometry. Baseline cell counts were compared to forty age and sex matched healthy persons. Post-transplantation cell counts of the 3 Thymoglobulin groups were compared to the 11 control patients, who received no induction therapy.

RESULTS

Absolute numbers of T, B, and NK cells were comparable in all patients pre-transplantation, but T and B cells were lower than in healthy persons (p=0.007 and p=0.0003, Mann Whitney test). In the first week, T cells and NK cells were significantly lower in all Thymoglobulin groups compared to controls. B cells were not affected. One month after Thymoglobulin NK cells had returned to control numbers in all groups, while T cells had already recovered to control counts in the 1.5 mg/kg group. During follow-up, T cells in the 3.0mg/kg group also returned to control values, but at one year the patients in the 6.0 mg/kg group still had significantly lower T cells (p=0.03). Patient and graft survival, rejection and infection incidence and renal function did not differ between groups.

CONCLUSION

Patients with end stage renal disease have significantly lower peripheral T and B cell counts than healthy persons. (Ultra-) low Thymoglobulin schedules deplete peripheral lymphocytes in a dose dependent way. Knowledge of the duration of this depletion contributes to finding the optimal immunosuppressive strategy for kidney transplant recipients.

Relationship of tacrolimus exposure and mycophenolate mofetil dose with renal function after renal transplantation

INTRODUCTION

The most common immunosuppressive treatment in de novo renal transplantation is a triple regimen that includes tacrolimus, mycophenolate mofetil (MMF) and corticosteroids, and that may also include antibody induction. Whether nephrotoxicity is an issue with tacrolimus at the currently used dosages remains an open question.

METHODS

We pooled data from three large, randomized, de novo renal transplantation studies (Symphony, Fixed Dose Concentration Controlled [FDCC], and OptiCept) that used variations of the triple regimen with respect to tacrolimus target levels, MMF dosing, and antibody induction. We used multivariate linear regression to explore the relationship of renal function at 1 year after transplantation (estimated glomerular filtration rate) with tacrolimus levels and MMF dose measured over the previous 6 months. The model included also a series of possible confounders. RESULTS.: The analysis population consisted of 998 patients. On average, tacrolimus levels were in a range considered low (mean ± standard deviation 7.2 ± 2.54 ng/mL), and MMF dose was 1.5 ± 0.61 g/day. Lower tacrolimus levels and higher MMF doses were associated with significantly better renal function. There were other variables associated with renal function, most notably acute rejection, donor age, and delayed graft function. Subanalyses in each of the three studies gave a consistent picture. There was no overt difference in the effect sizes when patients with stage II (estimated glomerular filtration rate 60-89 mL/min) or stage III (30-59 mL/min) chronic kidney disease were assessed separately.

CONCLUSION

Tacrolimus seems to have a moderate but consistent nephrotoxic effect even in modern efficient immunosuppressive regimens where it is used at lower doses than in previous years.

Induction antibody therapy in renal transplantation using early steroid withdrawal: long-term results comparing anti-IL2 receptor and anti-thymocyte globulin

BACKGROUND

The present study intends to investigate the effects of anti-IL2 receptors (anti-IL2R) vs. lymphocyte-depleting agents in the early steroid withdrawal (ESW) scheme.

METHODS

This is a retrospective cohort of 167 consecutive adult renal transplant recipients. Immunosuppression was based on tacrolimus and mycophenolate mofetil. Antibody induction therapy was carried out with lymphocyte-depleting agent (thymoglobulin) or anti-IL2R (Basiliximab or Daclizumab). ESW protocol was performed by administering intravenous methlyprednisolone as follows: 500 mg on day 0, 250 mg on day 1, 125 mg on day 2, 60 mg on day 3, and then stopped.

RESULTS

Among the 167 studied patients, 79 (47.3%) received anti-IL2R and 88 (52.7%) received thymoglobulin induction. Significantly fewer episodes of acute rejection were seen at one year in patients treated with thymoglobulin as compared to anti-IL2R (25.6% vs. 11.4%, p=0.01). At five years, a significant difference in graft survival was observed in anti-IL2R-treated patients compared with thymoglobulin (83.5% vs. 95.5%, p=0.01). Multivariate analysis disclosed that female sex, antibody induction therapy using thymoglobulin and a trough tacrolimus level higher than 10 were protective factors against acute rejection, while there was a trend to increased risk of acute rejection at first year post-transplantation in patients presenting delayed graft function (DGF). Antibody induction was independently associated with patient and graft survival at five years (OR 0.213, 95% CI 0.046-0.991, p=0.04).

CONCLUSION

ESW scheme seems to be safe and its use is beneficial since there are fewer adverse effects. Thymoglobulin induction therapy is associated with fewer rejection episodes. Induction therapy with thymoglobulin is associated with higher patient and allograft survival when comparing with anti-IL2R.

Obesity in renal transplantation: the role of induction therapy on long-term outcomes

Obesity is a burgeoning problem among renal transplant recipients given its association with increased morbidity, graft loss, and mortality. The long-term influence of different induction therapies in obese compared to nonobese patients is uncertain. We examined the long-term effect of low-dose rabbit antithymocyte globulin (rATG; 3-5 mg/kg) induction therapy compared to two doses of 20 mg basiliximab (BSX) in nonobese and obese renal transplant patients. The medical records of all adult (>18 years) recipients of kidney transplants between June 2001 and June 2009 in our center were reviewed. Patients whose body mass index (BMI) was greater than 30 were considered to be obese. The average dose of rATG was 3.2±1.6 mg/kg. A total of 475 patients were included. In the nonobese group with a BMI less than 30, 68 received BSX and 247, rATG. In the obese group, 27 patients were given BSX and 133 were given rATG. Mean follow-up was 1523 days. These four groups were similar in baseline characteristics including: donor and recipient age, percent diabetes, living donors, panel-reactive antibodies>35, HLA mismatch, race, gender, and maintenance immunosuppression. Serum creatinine levels at 3 months and 1, 5, and 7 years were not statistically different between groups. Compared to BSX induction therapy, rATG was associated with better graft survival at 47.4±10 months in obese (63.6% vs 90.3%, P<.05, respectively) as well as nonobese patients (68.2% vs 88.7%, P<.05, respectively). Rejections were numerically lower in rATG-treated obese patients, which reached statistical significance in nonobese patients. Wound and viral infections were not statistically different between rATG and BSX groups. Therefore, low-dose rATG is associated with a better long-term graft survival rate in obese patients without incurring an increased risk of infectious complications. When rATG was used in obese and nonobese patients, there was no difference in graft and patient survival.

Inflammation and the balance of Treg and Th17 cells in transplant rejection and tolerance

PURPOSE OF REVIEW

Inflammation of the allograft, occurring as a consequence of hypoxia and ischemia/reperfusion injury, adversely influences short-term and long-term transplant outcomes. Thus far, imbalance of tissue-protective Treg and tissue-destructive Th17 cells has been confirmed in a number of tissue-inflammatory states, including autoimmune disease. Hence, benefits of tilting Treg-Th17 equilibrium toward dominance of Tregs may promote transplant tolerance.

RECENT FINDINGS

Adverse graft inflammation creates extreme resistance to the induction of donor-specific tolerance. Proinflammatory cytokines, when abundantly expressed within the graft and draining lymph nodes, prevent commitment of donor-activated T cells into graft-protective, T-regulatory phenotype, while fostering generation of donor-reactive Th1, Th2 or Th17 effector subsets. In addition, the inflammatory milieu may destabilize the program of both natural and induced Tregs, converting them into inflammatory, effector-like phenotypes. Therefore permanent, Treg-dependent acceptance of an allograft may not be achieved without limiting adverse tissue inflammation.

SUMMARY

Balance of graft-protective regulatory and graft-destructive effector T cells largely depends on the balance of proinflammatory and anti-inflammatory cytokines in the milieu, in which donor-directed T-cell response occurs. In the absence of proinflammatory cytokines, the constitutive expression of TGF-beta may guide recipient T cells into a tissue-protective, pro-tolerant mode. Therefore, targeting adverse tissue inflammation may represent a powerful means to tilt antidonor immunity towards tolerance.

Heterogeneity of induction therapy in Spain: changing patterns according to year, centre, indications and results

Background. The use of induction drugs has increased markedly over the last 15 years in the USA, but there are few data about their use in other countries. Moreover, there are not enough data about when they are indicated and their long-term effects. The aim of our study was to know the rates of use and the drugs used as induction therapy, in which patients they were prescribed and the long-term graft survival effect in Spain.

Methods. We conducted a retrospective cohort study with adult patients (4861) receiving a kidney allograft in Spain over four different years (1990, 1994, 1998 and 2002) with a functioning graft at the end of the first post-transplant year. Induction therapy was defined as when the patient received polyclonal antibodies, OKT3 monoclonal antibodies or anti-CD25 monoclonal antibodies.

Results. From 1990 to 2002, the use of induction therapy in Spain changed, with a progressive reduction in the use of OKT3 and an increasing use of anti-CD25 antibodies. There were great differences in the rate of induction use from one centre to another, although with a common trend to greater use at each centre. Induction therapy was mainly prescribed in patients with a higher rejection risk (higher panel reactive antibody (PRA) titres and mismatches and re-transplants) and in older and diabetic recipients. Lastly, patients who were treated with induction therapy had significant higher allograft survival than those who did not (P value = 0.035).

Conclusions. The use of induction therapy in Spain has changed, with an increasing use of monoclonal antibodies in recent years. Induction therapy has a protective role in long-term graft survival.