Induction therapy in renal transplantation : an overview of current developments

Effects of Reduced-Dose Anti-Human T-Lymphocyte Globulin on Overall and Donor-Specific T-Cell Repertoire Reconstitution in Sensitized Kidney Transplant Recipients

Background

Pre-sensitized kidney transplant recipients have a higher risk for rejection following kidney transplantation and therefore receive lymphodepletional induction therapy with anti-human T-lymphocyte globulin (ATLG) whereas non-sensitized patients are induced in many centers with basiliximab. The time course of lymphocyte reconstitution with regard to the overall and donor-reactive T-cell receptor (TCR) specificity remains elusive.

Methods/Design

Five kidney transplant recipients receiving a 1.5-mg/kg ATLG induction therapy over 7 days and five patients with 2 × 20 mg basiliximab induction therapy were longitudinally monitored. Peripheral mononuclear cells were sampled pre-transplant and within 1, 3, and 12 months after transplantation, and their overall and donor-reactive TCRs were determined by next-generation sequencing of the TCR beta CDR3 region. Overall TCR repertoire diversity, turnover, and donor specificity were assessed at all timepoints.

Results

We observed an increase in the donor-reactive TCR repertoire after transplantation in patients, independent of lymphocyte counts or induction therapy. Donor-reactive CD4 T-cell frequency in the ATLG group increased from 1.14% + -0.63 to 2.03% + -1.09 and from 0.93% + -0.63 to 1.82% + -1.17 in the basiliximab group in the first month. Diversity measurements of the entire T-cell repertoire and repertoire turnover showed no statistical difference between the two induction therapies. The difference in mean clonality between groups was 0.03 and 0.07 pre-transplant in the CD4 and CD8 fractions, respectively, and was not different over time (CD4: F(1.45, 11.6) = 0.64 p = 0.496; CD8: F(3, 24) = 0.60 p = 0.620). The mean difference in R20, a metric for immune dominance, between groups was -0.006 in CD4 and 0.001 in CD8 T-cells and not statistically different between the groups and subsequent timepoints (CD4: F(3, 24) = 0.85 p = 0.479; CD8: F(1.19, 9.52) = 0.79 p = 0.418).

Conclusion

Reduced-dose ATLG induction therapy led to an initial lymphodepletion followed by an increase in the percentage of donor-reactive T-cells after transplantation similar to basiliximab induction therapy. Furthermore, reduced-dose ATLG did not change the overall TCR repertoire in terms of a narrowed or skewed TCR repertoire after immune reconstitution, comparable to non-depletional induction therapy.

Modest dose anti-thymocyte globulin administered intraoperatively is safe and effective in kidney transplantations: a retrospective study

BACKGROUND

Anti-thymocyte globulin (ATG) as induction therapy in renal transplantation is facing the dilemma of reducing the incidence of acute rejection (AR) and delayed graft function (DGF) or increasing risks of infection and malignancy. The purpose of this study was to delineate the safety and efficiency of the optimal ATG dosage.

METHODS

We retrospectively evaluated 91 deceased donor kidney transplant recipients (KTRs) in our institution between March 2011 and January 2019. The patients were classified into three groups based on induction therapy: (1) Group 1: modest-dose ATG (three mg/kg) intraoperatively (N = 21); (2) Group 2: low-dose ATG (1-1.5 mg/kg) intraoperatively (N = 23); (3) Group 3: basiliximab 20 mg both on day 0 and 4 (N = 47). In Groups 1 and 2, all patients received a daily low-dose program (1-1.5 mg/kg each day) with target dosage of six mg/kg. Induction therapy was combined with standard immunosuppressive regimen consisting of calcineurin inhibitors, mycophenolate/the mammalian target of rapamycin inhibitors and corticosteroids.

RESULTS

There was no significant difference in patient characteristics among groups. The outcomes of infection rate, biopsy-proven acute rejection, post-transplant diabetes mellitus, graft survival, and patient survival were similar among groups. Compared to the daily low-dose ATG regimen, the intraoperative modest-dose regimen did not cause more dose interruption and hence was more likely to reach the target ATG dosage. The intraoperative modest-dose regimen also seemed to reduce the rate of DGF.

DISCUSSION

In recent years, a trend of using a "lower" dose of ATG has seemed to emerge. Our results suggest intraoperative modest-dose ATG followed by daily low-dose ATG regimen was safe and effective in cadaveric renal transplantations for preventing DGF, AR, and graft loss.

Treatment with intravenous immunoglobulins and methylprednisolone may significantly decrease loss of renal function in chronic-active antibody-mediated rejection

Background

Chronic-active antibody mediated rejection (c-aABMR) is a major contributor to long-term kidney allograft loss. We conducted a retrospective analysis to establish the efficacy of treatment with intravenous immunoglobulins (IVIG) and pulse methylprednisolone (MP) of patients with c-aABMR.

Methods

Sixty-nine patients, in the period 2005–2017, with the diagnosis (suspicious for) c-aABMR that were treated with IVIG and MP were included. Patients were administered three doses of 1 g intravenous MP combined with a single dose of IVIG (1 g/kg body weight). Primary outcome was the decline in allograft function one year post treatment. Responders to IVIG-MP therapy were defined by an eGFR one year after treatment which was at least 25% above the projected allograft function.

Results

Patients showed an average decline in eGFR of 9.8 ml/min/1.73m² the year prior to treatment. Following treatment, a significant reduction (p < 0.001) in eGFR decline was observed (6.3 ml/min/1.73m²). Furthermore, a significant improvement in proteinuria was observed upon treatment (p < 0.001). Sixty-two percent (n = 43) of the patients were considered a responder and showed considerable slowing of graft function deterioration in the year after treatment (p < 0.001). Three and 5-year graft survival was significantly superior in responders.

Conclusions

More than 60% of patients with c-aABMR with a progressive decline in eGFR respond favorably to treatment with IVIG-MP resulting in a significant improvement of graft survival (Sablik, Am J Transplant 18, 2018).

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1385-z) contains supplementary material, which is available to authorized users.

Belatacept-based, ATG-Fresenius-induction regimen for kidney transplant recipients: a proof-of-concept study

Belatacept provides effective immunosuppression while avoiding the nephrotoxicities associated with calcineurin inhibitors (CNIs). However, existing belatacept-based regimens still have high rates of acute rejection. We hypothesized that therapy with belatacept, mycophenolic acid (MMA), steroids and induction therapy with rabbit anti-thymocyte globulin Fresenius (ATGF), rejection rate could be reduced. Prospective, single center, proof-of-concept study including males and females aged ≥18years, Epstein-Barr virus (EBV)-seropositive recipients of a first, HLA non-identical, live or deceased donor kidney allograft. Only patients with a calculated panel reactive antibody score of 0% were included. Three donors were positive for Chagas disease. Six of twelve patients had at least one infection and five were readmitted to the hospital for treatment. One patient had a Trypanosoma cruzi infection via the graft treated successfully. Median cold ischemia time for the transplant patients with a deceased donor was 21.5h. Mean serum creatinine levels at 1, 3 and 6months were 1.76±0.59, 1.55±0.60 and 1.49±0.60mg/dl, respectively. Two of twelve patients experienced clinical, biopsy-proven rejection, successfully treated with methylprednisolone. No patient developed post-transplant lymphoproliferative disorder (PTLD) or any other malignancy and no patient lost their graft or died during follow-up. The potential of this approach makes it worthy of further investigation.

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 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.

Rabbit antithymocyte globulin (thymoglobulin): a review of its use in the prevention and treatment of acute renal allograft rejection

Rabbit antithymocyte globulin (rATG) [Thymoglobulin(R); Thymoglobuline(R)] is a purified, pasteurized preparation of polyclonal gamma immunoglobulin raised in rabbits against human thymocytes that is indicated for the prevention and/or treatment of renal transplant rejection in several countries worldwide. rATG induction in combination with immunosuppressive therapy is more effective in preventing episodes of acute renal graft rejection in adult renal transplant recipients than immunosuppressive therapy without induction. The efficacy of rATG induction is generally better than that of equine antithymocyte globulin (eATG) induction and generally no different from that of basiliximab or low-dose daclizumab induction in this patient population. However, in high-risk patients, rATG induction was more effective than daclizumab or basiliximab induction in preventing acute renal graft rejection. In the treatment of renal graft rejection in adult renal transplant recipients, rATG was more effective than eATG in terms of the successful response rate, although the agents generally did not differ with regard to most other endpoints. Both induction and treatment with rATG are generally well tolerated, although adverse events, such as fever, leukopenia and thrombocytopenia, appear more common with rATG than with other antibody preparations. The overall incidence of infection associated with rATG induction was generally no different from that seen with eATG or basiliximab induction, although was higher with rATG than with basiliximab in high-risk patients. The incidence of cytomegalovirus (CMV) disease generally did not differ between rATG and eATG induction, and there was no significant difference between rATG and daclizumab induction with regard to the incidence of CMV infections or the proportion of patients who received treatment for a CMV episode or infection. Relative to basiliximab, the incidence of CMV infection was generally higher with rATG, except in high-risk patients. In the treatment of acute renal rejection, the nature and incidence of infections were generally similar with rATG and eATG. The incidence of malignancies is generally low with rATG therapy and generally does not differ from that seen with other agents. Further prospective comparative studies would be beneficial in order to definitively position rATG with respect to other antibody preparations. In the meantime, available clinical data suggest that rATG is an effective and generally well tolerated option for the prevention and treatment of acute renal graft rejection in renal transplant recipients.