Induction immunosuppressive therapies in renal transplantation

Management of kidney transplant recipients for primary care practitioners

Patients with kidney transplants have a significant co-morbidity index, due to a high number of pre-existing conditions and use of immunosuppression medications. These patients are at higher risk of developing conditions such as hypertension, dyslipidemia, post-transplant diabetes, cardiovascular events, and anemia. Moreover, they are particularly susceptible to infections such as urinary tract infections or pyelonephritis, cancers, and gastrointestinal complications such as diarrhea, which in turn may be attributed to medication adverse effects or infectious causes. Along with these concerns, meticulous management of electrolytes and allograft function is essential. Prior to prescribing any new medications, it is imperative to exercise caution in identifying potential interactions with immunosuppression drugs. This review aims to equip primary care practitioners to address these complex issues and appropriate methods of delivering care to this rapidly growing highly susceptible group.

Use of antithymocyte globulin (rabbit) in a patient with known alpha-gal syndrome undergoing allogenic stem cell transplantation

INTRODUCTION

Alpha-gal syndrome (AGS) is a hypersensitivity disorder in which tick bites-most commonly from the lone star tick (Ambylomma americanum)-trigger immunoglobulin E-mediated hypersensitivity reaction upon exposure to oligosaccharide galactosse-alpha-1,3-galactose (α-gal). α-gal is most notorious for being found in "red meat" products but is present in mammalian meats such as beef, pork, lamb, rabbit, and others. Manifestations of AGS hypersensitivity are variable. There is currently no in vivo data describing allergic reactions against rabbit products in patients with AGS.

CASE REPORT

Here, we describe a case of a 44-year-old male with myelodysplastic syndrome and a known history of AGS undergoing allogeneic hematopoietic cell transplantation (allo-HSCT) with the use of rabbit antithymocyte globulin (rATG) for graft-versus-host disease (GVHD) prophylaxis.

MANAGEMENT AND OUTCOME

The risk of cross-reactivity against rATG in our patient with AGS could not be ruled out and, therefore, a test dose was administered. The patient tolerated the test dose with no signs of anaphylaxis. After demonstrating tolerance to the test dose, rATG was utilized for GVHD prophylaxis.

DISCUSSION

Due to the heterogeneity of AGS manifestations in patients, the use of rATG in patients with known AGS should be considered on a case-by-case basis. The administration of a test dose may help predict the occurrence of severe hypersensitivity reactions. The limited data surrounding the risk of AGS with rabbit-containing products and the various indications for the use of rATG warrants more in-depth study of the reactivity of this medication in this population.

A Fresh Glimpse into Cartilage Immune Privilege

The increasing prevalence of degenerative cartilage disorders in young patients is a growing public concern worldwide. Cartilage's poor innate regenerative capacity has inspired the exploration and development of cartilage replacement treatments such as tissue-engineered cartilages and osteochondral implants as potential solutions to cartilage loss. The clinical application of tissue-engineered implants is hindered by the lack of long-term follow-up demonstrating efficacy, biocompatibility, and bio-integration. The historically reported immunological privilege of cartilage tissue was based on histomorphological observations pointing out the lack of vascularity and the presence of a tight extracellular matrix. However, clinical studies in humans and animals do not unequivocally support the immune-privilege theory. More in-depth studies on cartilage immunology are needed to make clinical advances such as tissue engineering more applicable. This review analyzes the literature that supports and opposes the concept that cartilage is an immune-privileged tissue and provides insight into mechanisms conferring various degrees of immune privilege to other, more in-depth studied tissues such as testis, eyes, brain, and cancer.

Optimal Immunosuppression Strategy in the Sensitized Kidney Transplant Recipient

Patients with previous sensitization events against anti-human leukocyte antigens (HLA) often have circulating anti-HLA antibodies. Following organ transplantation, sensitized patients have higher rates of antibody-mediated rejection (AMR) compared to those who are non-sensitized. More stringent donor matching is required for these patients, which results in a reduced donor pool and increased time on the waitlist. Current approaches for sensitized patients focus on reducing preformed antibodies that preclude transplantation; however, this type of desensitization does not modulate the primed immune response in sensitized patients. Thus, an optimized maintenance immunosuppressive regimen is necessary for highly sensitized patients, which may be distinct from non-sensitized patients. In this review, we will discuss the currently available therapeutic options for induction, maintenance, and adjuvant immunosuppression for sensitized patients.

Impact of the immunotherapy induction on allograft outcome and survival in kidney transplant patients with donor-specific antibodies to HLA-DQB1

BACKGROUND

The presence of donor-specific antibodies (DSAs) against HLA-DQB1 is considered a significant barrier to good outcome and allograft survival in kidney transplantation (KT). This study aimed to assess the impact of induction immunotherapy on the outcome and allograft survival in KT patients with HLA-DQB1-DSA.

METHODOLOGY

Thirty-two patients who had undergone KT and found to be positive for HLA-DQB1-DSA were monitored at least one to 10 years. They were allocated into two groups of patients: G1 received induction immunotherapy (n = 14 patients; 43.75%), and G2 did not (n = 18 patients; 56.25%).

RESULTS

In G1, 6 (42.86%) patients experienced rejection episodes (RE), 2 (14.29%) due to antibody-mediated rejection (ABMR) and 4 (28.57%) due to T-cell-mediated rejection (TCMR). In G2, 13 (72.22%) patients experienced RE, 3 (16.67%) due to ABMR, and 10 (55.56%) due to TCMR. Graft loss occurred in 4 patients from G1, 2 (14.29%) due to ABMR and 2 (14.29%) due to non-immunological causes. In G2, 9 (50.00%) patients lost their grafts, 2 (11.11%) due to TCMR, 2 (11.11%) due to ABMR, and 5 (27.78%) due to non-immunological causes. The graft survival rate was 64.29% in G1 and 45.83% in G2. Glomerulitis and peritubular capillaritis were observed in 3 and C4d-positive patients with/or without induction who lost their grafts by ABMR by HLA-DQ DSA. Two patients from G2 lost their graft by TCMR due to interstitial lymphocytic infiltrate (i1), foci of mild tubulitis (t2), interstitial edema, moderate interstitial fibrosis and tubular atrophy. Better graft survival rates were shown in patients from G1 who received induction immunotherapy.

CONCLUSION

Our study suggests that patients with an immunological profile of HLA-DQ+ DSA+ treated by immunotherapy induction have a decreased risk of ABMR and increased allograft survival, and the presence of anti-HLA-DQB1 DSA+ detected before and after KT were associated with ABMR episodes and failure.

Variable Benefits of Antibody Induction by Kidney Allograft Type

BACKGROUND

Kidneys from acute renal failure (ARF), expanded criteria donors (ECD), and donation after cardiac death (DCD) donors are often discarded due to concerns for delayed graft function (DGF) and graft failure. Induction immunosuppression may be used to minimize these risks, but practices vary widely. Furthermore, little is known regarding national outcomes of transplant recipients receiving induction immunosuppression for receipt of high-risk kidneys.

MATERIALS AND METHODS

Using a center-level retrospective study, deceased donor transplants (115,485) from the Scientific Registry of Transplant Recipients from January 2003 to June 2016 were evaluated. Patients who received induction immunosuppression, including lymphocyte immune globulin, muromonab CD-3, IL-1 receptor antagonist, anti-thymocyte globulin, daclizumab, basiliximab, alemtuzumab, and rituximab, were included. Associations of center-level induction use with acute rejection in the first post-transplant year, graft failure, and patient mortality were evaluated using multivariable Cox and logistic regression.

RESULTS

Among all kidneys, increasing percentage of center-level induction was associated with lower risk of graft failure, acute rejection, and patient mortality. In recipients of ARF kidneys, the beneficial association of induction on graft failure and acute rejection was greater than in those that received non-ARF kidneys. Marginally greater benefit of induction was seen for acute rejection in ECD compared to standard criteria donor (SCD) recipients and for graft failure in DCD compared to donors after brain death (DBD). No benefit of induction was detected for patient and graft survival in ECD recipients, acute rejection in DCD recipients, and patient survival in DGF recipients. No difference in the benefit of induction was detected in any other comparisons.

CONCLUSIONS

While seemingly beneficial for recipients of all kidneys, induction has more robust associations with lower graft failure and acute rejection probability for recipients of ARF kidneys. Given the lack of observed benefit for ECD recipients, induction policies should be carefully considered in these patients.

Kidney transplant outcomes in HIV-positive patients: a systematic review and meta-analysis

Background

Kidney transplantation is now a viable alternative to dialysis in HIV-positive patients who achieve good immunovirological control with the currently available antiretroviral therapy regimens. This systematic review and meta-analysis investigate the published evidence of outcome and risk of kidney transplantation in HIV-positive patients following the PRISMA guidelines.

Methods

Searches of PubMed, the Cochrane Library and EMBASE identified 27 cohort studies and 1670 case series evaluating the survival of HIV-positive kidney transplant patients published between July 2003 and May 2018. The regimens for induction, maintenance therapy and highly active antiretroviral therapy, acute rejection, patient and graft survival, CD4 count and infectious complications were recorded. We evaluated the patient survival and graft survival at 1 and 3 years respectively, acute rejection rate and also other infectious complications by using a random-effects analysis.

Results

At 1 year, patient survival was 0.97 (95% CI 0.95; 0.98), graft survival was 0.91 (95% CI 0.88; 0.94), acute rejection was 0.33 (95% CI 0.28; 0.38), and infectious complications was 0.41 (95% CI 0.34; 0.50), and at 3 years, patient survival was 0.94 (95% CI 0.90; 0.97) and graft survival was 0.81 (95% CI 0.74; 0.87).

Conclusions

With careful selection and evaluation, kidney transplantation can be performed with good outcomes in HIV-positive patients.

Effects of immunotherapy induction on outcome and graft survival of kidney-transplanted patients with different immunological risk of rejection

BACKGROUND

In kidney transplantation, immunotherapy with thymoglobulin (rATG) has been used to down-regulate the patient immune system. rATG is a powerful immunobiologic drug used to deplete lymphocytes to prevent early acute rejection. The aim of this research was to evaluate the effects of immunotherapy by rATG on graft suvival during a 9-year period in kidney-transplanted patients with different immunological profiles.

METHODS

A sample of 469 patients were allocated into four groups (G) based on immunological risk of rejection: G1, low risk, not sensitized recipients, solid-phase immunoassay with single antigen beads (SPI-SAB) < 10%; G2, medium risk I, sensitized recipients, SPI-SAB ≥ 10 < 50%; G3, medium risk II sensitized (SPI-SAB ≥50%); and G4, high risk, sensitized recipients, SPI-SAB- donor-specific antibody positive (DSA+). Only patients from G3 and G4 received immunotherapy.

RESULTS

Of 255 patients who received a kidney from a living donor (LD), 42 (16.47%) from all groups (G) had T-cell-mediated rejection (TCMR) and four (G1) lost their grafts, 8 (3.14%) had antibody-mediated rejection (AMR), and two lost their graft in G1 and G4. Of 214 patients who received a kidney from deceased donors (DD), 37 (17.29%) had TCMR with one lost graft in G1. AMR was shown in 13 (6.07%) patients, with three losses observed in G2. Statistical differences between the groups in the 9-year graft survival rate were found only in the comparison of G1 versus G2 (P = 0.005) and G2 versus G4 (P = 0.047) for DD. For LD, no statistical differences were found.

CONCLUSION

This clinical retrospective study shows that immunotherapy induction was associated with improvement of outcomes, graft function, and survival in patients treated with immunotherapy in comparison with patients who did not received induction therapy. These findings strongly suggest that immunotherapy should be used for all patients transplanted with kidneys from deceased donors.

Comparison of Alemtuzumab Versus Basiliximab Induction Therapy in Elderly Kidney Transplant Recipients: A Single-Center Experience

BACKGROUND

The optimal choice of induction immunosuppression for elderly kidney transplant recipients remains unclear. Although alemtuzumab has been associated with escalating risk of death and graft loss in this population, this risk has not been adequately explored. The purpose of this study was to compare the safety and efficacy of alemtuzumab with basiliximab induction in this population.

METHODS

This is a retrospective matched cohort study of kidney transplant recipients aged ≥65 years. Patients who received alemtuzumab induction were matched (1:2) to a basiliximab control. The primary outcome was allograft survival. The incidence of acute rejection, infection, and all-cause mortality was measured.

RESULTS

Fifty-one and 102 patients were included in the alemtuzumab and basiliximab groups, respectively. Baseline demographics were similar between groups, except for more living donor transplant recipients in the alemtuzumab group (26/51 [51%] vs 31/102 [30.4%], P = .02). Acute cellular rejection occurred more frequently within the first year in the basiliximab group (P = .02). There was no difference in rates of infection within the first year. Graft and patient survival rates were similar over the follow-up period. Patients receiving basiliximab had a higher glomerular filtration rate at 2 years posttransplant (59 mL/min/1.73 m² vs 49 mL/min/1.73 m², P = .03).

CONCLUSIONS

Alemtuzumab induction is associated with similar outcomes to basiliximab in elderly kidney transplant recipients.

Lack of Benefit and Potential Harm of Induction Therapy in Simultaneous Liver-Kidney Transplants

The number of simultaneous liver-kidney transplantations (SLKTs) and use of induction therapy for SLKT have increased recently, without much published evidence, especially in the context of maintenance immunosuppression containing tacrolimus (TAC) and mycophenolic acid (MPA). We queried the Organ Procurement and Transplant Network registry for SLKT recipients maintained on TAC/MPA at discharge in the United States for 2002-2016. The cohort was divided into 3 groups on the basis of induction type: rabbit antithymocyte globulin (r-ATG; n = 831), interleukin 2 receptor antagonist (IL2RA; n = 1558), and no induction (n = 2333). Primary outcomes were posttransplant all-cause mortality and acute rejection rates in kidney and liver allografts at 12 months. Survival rates were analyzed by the Kaplan-Meier method. A propensity score analysis was used to control potential selection bias. Multivariate inverse probability weighted Cox proportional hazard and logistic regression models were used to estimate the hazard ratios (HRs) and odds ratios. Among SLKT recipients, survival estimates at 3 years were lower for recipients receiving r-ATG (P = 0.05). Compared with no induction, the multivariate analyses showed an increased mortality risk with r-ATG (HR, 1.29; 95% confidence interval [CI], 1.10-1.52; P = 0.002) and no difference in acute liver or kidney rejection rates at 12 months across all induction categories. No difference in outcomes was noted with IL2RA induction over the no induction category. In conclusion, there appears to be no survival benefit nor reduction in rejection rates for SLKT recipients who receive induction therapy, and r-ATG appears to increase mortality risk compared with no induction.

Over ten-year insulin independence following single allogeneic islet transplant without T-cell depleting antibody induction

Islet cell transplantation is a promising functional cure for type 1 diabetes; however, maintaining long-term islet graft function and insulin independence is difficult to achieve. In this short report we present a patient with situs inversus, who at the time of islet transplantation had a 26-year history of type 1 diabetes, complicated by hypoglycemic unawareness and severe hypoglycemic events. After a single allogeneic islet transplant of a low islet mass, and despite developing de novo anti-insulin and anti-GAD65 autoantibodies, the patient has remarkably maintained insulin independence with tight glycemic control and normal metabolic profiles for 10 years, after receiving prolonged non-T-cell depleting immunosuppression.

Treatment of membranous nephropathy: time for a paradigm shift

In patients with membranous nephropathy, alkylating agents (cyclophosphamide or chlorambucil) alone or in combination with steroids achieve remission of nephrotic syndrome more effectively than conservative treatment or steroids alone, but can cause myelotoxicity, infections, and cancer. Calcineurin inhibitors can improve proteinuria, but are nephrotoxic. Most patients relapse after treatment withdrawal and can become treatment dependent, which increases the risk of nephrotoxicity. The discovery of nephritogenic autoantibodies against podocyte M-type phospholipase A2 receptor (PLA₂R) and thrombospondin type-1 domain- containing protein 7A (THSD7A) antigens provides a clear pathophysiological rationale for interventions that specifically target B-cell lineages to prevent antibody production and subepithelial deposition. The anti-CD20 monoclonal antibody rituximab is safe and achieves remission of proteinuria in approximately two-thirds of patients with membranous nephropathy. In those with PLA₂R-related disease, remission can be predicted by anti-PLA₂R antibody depletion and relapse by antibody re-emergence into the circulation. Thus, integrated evaluation of serology and proteinuria could guide identification of affected patients and treatment with individually tailored protocols. Nonspecific and toxic immunosuppressive regimens will fall out of use. B-cell modulation by rituximab and second-generation anti-CD20 antibodies (or plasma cell-targeted therapy in anti-CD20 resistant forms of disease) will lead to a novel therapeutic paradigm for patients with membranous nephropathy.

Total Recall: Can We Reshape T Cell Memory by Lymphoablation?

Despite recent advances in immunosuppression, donor-reactive memory T cells remain a serious threat to successful organ transplantation. To alleviate damaging effects of preexisting immunologic memory, lymphoablative induction therapies are used as part of standard care in sensitized recipients. However, accumulating evidence suggests that memory T cells have advantages over their naive counterparts in surviving depletion and expanding under lymphopenic conditions. This may at least partially explain the inability of existing lymphoablative strategies to improve long-term allograft outcome in sensitized recipients, despite the well-documented decrease in the frequency of early acute rejection episodes. This minireview summarizes the insights gained from both experimental and clinical transplantation as to the effects of existing lymphoablative strategies on memory T cells and discusses the latest research developments aimed at improving the efficacy and safety of lymphoablation.

Comparing Outcomes between Antibody Induction Therapies in Kidney Transplantation

Kidney transplant recipients often receive antibody induction. Previous studies of induction therapy were often limited by short follow-up and/or absence of information about complications. After linking Organ Procurement and Transplantation Network data with Medicare claims, we compared outcomes between three induction therapies for kidney recipients. Using novel matching techniques developed on the basis of 15 clinical and demographic characteristics, we generated 1:1 pairs of alemtuzumab-rabbit antithymocyte globulin (rATG) (5330 pairs) and basiliximab-rATG (9378 pairs) recipients. We used paired Cox regression to analyze the primary outcomes of death and death or allograft failure. Secondary outcomes included death or sepsis, death or lymphoma, death or melanoma, and healthcare resource utilization within 1 year. Compared with rATG recipients, alemtuzumab recipients had higher risk of death (hazard ratio [HR], 1.14; 95% confidence interval [95% CI], 1.03 to 1.26; P<0.01) and death or allograft failure (HR, 1.18; 95% CI, 1.09 to 1.28; P<0.001). Results for death as well as death or allograft failure were generally consistent among elderly and nonelderly subgroups and among pairs receiving oral prednisone. Compared with rATG recipients, basiliximab recipients had higher risk of death (HR, 1.08; 95% CI, 1.01 to 1.16; P=0.03) and death or lymphoma (HR, 1.12; 95% CI, 1.01 to 1.23; P=0.03), although these differences were not confirmed in subgroup analyses. One-year resource utilization was slightly lower among alemtuzumab recipients than among rATG recipients, but did not differ between basiliximab and rATG recipients. This observational evidence indicates that, compared with alemtuzumab and basiliximab, rATG associates with lower risk of adverse outcomes, including mortality.

Induction Immunosuppression and Clinical Outcomes in Kidney Transplant Recipients Infected With Human Immunodeficiency Virus

There is an increased risk of acute rejection (AR) in human immunodeficiency virus-positive (HIV+) kidney transplant (KT) recipients. Induction immunosuppression is standard of care for those at high risk of AR; however, use in HIV+ patients is controversial, given fears of increased infection rates. We sought to compare clinical outcomes between HIV+ KT recipients who were treated with (i) anti-thymocyte globulin (ATG), (ii) IL-2 receptor blocker, and (iii) no induction. We studied 830 HIV+ KT recipients between 2000 and 2014, as captured in the Scientific Registry of Transplant Recipients, and compared rates of delayed graft function (DGF), AR, graft loss and death. Infections and hospitalizations were ascertained by International Classification of Diseases, Ninth Revision codes in a subset of 308 patients with Medicare. Compared with no induction, neither induction agent was associated with an increased risk of infection (weighted hazard ratio [wHR] 0.80, 95% confidence interval [CI] 0.55-1.18). HIV+ recipients who received induction spent fewer days in the hospital (weighted relative risk [wRR] 0.70, 95% CI 0.52-0.95), had lower rates of DGF (wRR 0.66, 95% CI 0.51-0.84), less graft loss (wHR 0.47, 95% CI 0.24-0.89) and a trend toward lower mortality (wHR 0.60, 95% CI 0.24-1.28). Those who received induction with ATG had lower rates of AR (wRR 0.59, 95% CI 0.35-0.99). Induction in HIV+ KT recipients was not associated with increased infections; in fact, those receiving ATG, the most potent agent, had the lowest rates. In light of the high risk of AR in this population, induction therapy should be strongly considered.

Basiliximab versus rabbit antithymocyte globulin as induction therapy for living-related renal transplantation: a single-center experience

PURPOSE

To compare the long-term effects of the interleukin-2 receptor antagonist basiliximab versus rabbit antithymocyte globulin as an induction therapy for living-related renal transplantation.

METHODS

This is a prospective, open-label, nonrandomized, controlled study including 213 cases of renal transplant. Immunosuppressive therapy containing calcineurin inhibitors, mycophenolate mofetil and steroids was applied in all cases. The interleukin-2 receptor antagonist group (IL2Ra group) included 108 cases with 20 mg basiliximab induction on Day 0 and Day 4. The other 105 cases comprised the rabbit antithymocyte globulin group (rATG group) with 1.0 mg/kg/day ATG induction from Day 0 to Day 4. The primary endpoint was biopsy-proven acute rejection. Other endpoints included delayed graft function (DGF), graft loss and death.

RESULTS

All patients were followed up for 3 years. Acute rejection rates in the IL2Ra group and the ATG group were 5.6 and 3.8 % (P = 0.781), and the differences in the DGF rates, graft loss and death were insignificant between groups. All-cause infection rates in the IL2Ra and rATG groups were 26.9 and 43.8 % (P = 0.010). Urinary tract infections were more common in the rATG group than in the IL2Ra group (15.2 vs 6.5 %, P = 0.040). Specific viral infection rates were significantly different (18.1 % in rATG group vs 8.3 % in IL2Ra group, P = 0.035).

CONCLUSIONS

IL2Ra and rATG had no significant differences as induction therapies during the perioperative period of living-related renal transplantation, according to acute rejection rates, DGF rates, graft loss, 1- and 3-year patient/graft survival rates. However, the incidence of infection, especially of urinary tract infection and specific viral infection, was higher in rATG-induced patients.

Similar survival in patients following heart transplantation receiving induction therapy using daclizumab vs. basiliximab

BACKGROUND

Induction therapy with interleukin-2 receptor antagonists has been established as an effective immunosuppressive strategy in the management of heart transplant (HTx) recipients. We compared outcomes following HTx in patients receiving basiliximab, daclizumab, or no induction therapy.

METHODS AND RESULTS

We investigated post-transplant prognosis of patients receiving basiliximab (n=67), daclizumab (n=98) or no induction therapy (n=70). Patients treated with daclizumab (50.3 ± 14.7 years) were younger than those receiving basiliximab (55.8 ± 11.2 years) or no induction therapy (54.9 ± 14.1 years; both P<0.05). Patients receiving either induction therapy showed better survival 1 year after HTx (95%) than those without induction therapy (82%; P<0.001). Survival was similar between patients receiving basiliximab and daclizumab. The incidence of acute cellular or antibody-mediated rejections did not differ among the groups. The main reason that patients did not receive induction therapy was ongoing infection (65.7%), which was more common in patients on ventricular assist device (VAD) support than those without VAD (76.1% vs. 45.8%; P=0.004). The VAD-related infection rate in the entire study cohort was 29.7% (35/118 VAD recipients).

CONCLUSIONS

Survival following HTx was worse in patients not receiving induction therapy. No differences were noted in survival or the incidence of rejection between the daclizumab- and basiliximab-treated groups. Induction therapy was less used in patients with infection, which was related to prior VAD support.

Rituximab in primary membranous nephropathy: first-line therapy, why not?

The ideal treatment of patients with primary membranous nephropathy (MN) and persistent nephrotic syndrome (NS) is still a matter of debate. This is a major issue since these patients may progress to end-stage kidney disease (ESKD) in 5-10 years. Steroids, alkylating agents, and calcineurin inhibitors have been suggested to achieve NS remission and prevent ESKD in this population. Treatment benefits, however, are uncertain and are often offset by serious adverse events (SAEs). Evidence that B cells play a crucial role in the pathogenesis of the disease, both as precursors of autoantibody-producing cells and as antigen-presenting cells, provided the background for explorative studies testing the role of B cell-depletion therapy with the monoclonal antibody rituximab. This approach aimed at selectively inhibiting disease mechanisms without the devastating consequences of unspecific immunosuppression. Finding that rituximab safely ameliorated NS in 8 patients with primary MN fueled a series of observational studies that uniformly confirmed the safety/efficacy profile of rituximab in this context. Although head-to-head comparisons in randomized clinical trials are missing, comparative analyses between series of homogeneous patient cohorts clearly show at least similar efficacy of rituximab as compared to steroid plus alkylating agents. Moreover, data confirm the dramatically superior safety profile of rituximab that actually appears to be associated with a rate of SAEs even lower than that observed with conservative therapy. Rituximab is also effective in patients resistant to other treatments and its cost-effectiveness is further increased when treatment is titrated to circulating B cells. Recently identified pathogenic antibodies against the M type phospholipase A2 receptor will likely provide a novel tool to monitor disease activity and drive rituximab therapy, at least in a subset of patients. Newly developed anti-CD20 antibodies could represent a valuable option for those who fail rituximab therapy. Steroids, alkylating agents, and calcineurin inhibitors should likely be abandoned.

Islet cell transplantation for the treatment of type 1 diabetes: recent advances and future challenges

Islet transplantation is a well-established therapeutic treatment for a subset of patients with complicated type I diabetes mellitus. Prior to the Edmonton Protocol, only 9% of the 267 islet transplant recipients since 1999 were insulin independent for >1 year. In 2000, the Edmonton group reported the achievement of insulin independence in seven consecutive patients, which in a collaborative team effort propagated expansion of clinical islet transplantation centers worldwide in an effort to ameliorate the consequences of this disease. To date, clinical islet transplantation has established improved success with insulin independence rates up to 5 years post-transplant with minimal complications. In spite of marked clinical success, donor availability and selection, engraftment, and side effects of immunosuppression remain as existing obstacles to be addressed to further improve this therapy. Clinical trials to improve engraftment, the availability of insulin-producing cell sources, as well as alternative transplant sites are currently under investigation to expand treatment. With ongoing experimental and clinical studies, islet transplantation continues to be an exciting and attractive therapy to treat type I diabetes mellitus with the prospect of shifting from a treatment for some to a cure for all.

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.

Immunoglobulin G measurement in blood plasma using infrared spectroscopy

A rapid, simple, and inexpensive method to measure the immunoglobulin G (IgG) concentrations in blood samples in human and veterinary medicine is highly desired. Infrared spectroscopy (coupled with chemometric manipulation of spectral data) has the advantages of simple sample preparation, rapid implementation of analysis, and low cost. Here a method that exploits infrared spectroscopy as the basis to measure IgG concentration in animal plasma samples is reported, with radial immunodiffusion (RID) used as the reference test method for partial least squares (PLS) calibration model development. Smoothed non-derivative and the second-order derivative spectra were used to develop calibration models. Various additional spectral preprocessing steps were evaluated to optimize the calibration models, and the possible benefits of using an internal standard (potassium thiocyanate [KSCN]) were investigated. Monte Carlo cross-validation was used to determine the optimal number of PLS factors, and an independent prediction set was used to test the predictive performances of provisional models. The effects of various preprocessing options (spectral smoothing, derivation, normalization, region selection, mean-centering, and standard deviation scaling) on quantification accuracy were investigated. The root mean squared error of prediction (RMSEP) for different combinations of spectra preprocessing steps was 394 ± 36 mg/dL for the non-derivative spectra and 427 ± 101 mg/dL for the second-order derivative spectra. Immunoglobulin G concentrations produced by the optimized PLS model for the non-derivative spectra (RMSEP = 352 mg/dL) were found to be stable with respect to different splits of the samples among the calibration, validation, and prediction sets. The precision of the Fourier transform infrared (FT-IR) method is found to be slightly superior to that of the RID method. The results of this work indicate that infrared spectroscopy is a promising technique for economically and rapidly determining the IgG concentrations of plasma and plasma-derived samples.

Biologic agents in islet transplantation

Islet transplantation is today an accepted modality for treating selected patients with frequent hypoglycemic events or severe glycemic lability. Despite tremendous progress in islet isolation, culture, and preservation, clinical use is still restricted to a limited subset, and lifelong immunosuppression is required. Issues surrounding limited islet revascularization and immune destruction remain. One of the major challenges is to prevent alloreactivity and recurrence of autoimmunity against β-cells. These two hurdles can be effectively reduced by immunosuppressive therapy combining induction and maintenance treatments. The introduction of highly potent and selective biologic agents has significantly reduced the frequency of acute rejection and has prolonged graft survival, while minimizing the complications of this therapeutic scheme. This review will address the most important biological agents used in islet transplantation. We provide a historical perspective of their introduction into clinical practice and their role in current clinical protocols, aiming at improved engraftment efficiency, increased long-term survival, and better overall results of clinical islet transplantation.

Filtering lymphocytes may decrease the need for immunosuppression in solid organ transplantation

Organ transplantation has become very important for patients with irreversible organ diseases. The transplanted organ is foreign to the host and, therefore, it induces a complex immune response of the patient. Therefore, Immunosuppressive agents are usually required to suppress both specific and nonspecific immunity and prevent allograft rejection in recipients who undergo organ transplantation. Of the late years, newer immunosuppressive agents with non-overlapping toxicities have been used in combinations in order to provide better patient and graft survival. However, these medications are associated with significant adverse effects that impact quality of life and sometimes long-term survival of the patient. Adverse effects can differ between the immunosuppressants, but many result from the overall state of immunosuppression. Strategies to manage immunosuppressant adverse effects often involve minimizing exposure to the drugs while balancing the risk for rejection. However, to prevent rejection of the transplanted organ, there may be unproven approaches other than immunosuppressive drugs. Filtering lymphocytes by a specific filter with respect to their size can be an alternative way. Our hypothesis was concerning of if such a filter could manage this and take the place of these drugs.

Alemtuzumab for cytolytic induction of immunosuppression in heart transplant recipients

OBJECTIVE

To review available evidence about the safety and efficacy of alemtuzumab for induction of immunosuppression in heart transplant recipients.

DATA SOURCES

Searches of MEDLINE, EMBASE, and Cochrane databases were conducted. Key search terms included alemtuzumab, Campath-1H, CD52, lymphocyte, cytolytic, induction, immunosuppression, rejection, and cardiac transplantation. Additional pertinent data were identified through a search of abstracts from major transplant meetings.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles and abstracts identified from the data sources were evaluated. All primary data were eligible for inclusion if they evaluated the safety or efficacy of alemtuzumab for induction of immunosuppression in heart transplant patients. One retrospective cohort, 1 case series, 1 case-control series, and 1 open-label trial were identified and included for review.

DATA SYNTHESIS

Acute cellular rejection occurs in 40% to 70% of heart transplant recipients within the first 6 months after transplant and is associated with significant morbidity and mortality. Depleting and nondepleting antibodies have displayed positive outcomes in inducing immunosuppression; however, the ideal induction strategy that balances efficacy and toxicity remains elusive. Alemtuzumab, a cytolytic anti-CD52 antibody, has been used to induce immunosuppression in kidney, pancreas, liver, intestine, and lung transplant recipients, and its use in heart transplant has been investigated. Studies of use of alemtuzumab to induce immunosuppression in heart transplant patients have shown low rates of rejection; however, it has not been directly compared with other immunosuppression-inducing agents and safety data are limited.

CONCLUSIONS

Although alemtuzumab may be a practical option for inducing immunosuppression, data are insufficient to recommend its routine use in deference to more established agents. Large, randomized clinical trials with extended durations of follow-up must be conducted to characterize its efficacy and safety further.

Is it safe to withdraw steroids within seven days of renal transplantation?

BACKGROUND

The safety of very early steroid withdrawal (VESW) in renal transplant recipients remains unclear.

METHODS

Literature searches for all randomized controlled trials comparing VESW with steroid maintenance regimens 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) and weighted mean difference with 95% confidence intervals (CI).

RESULTS

A total of 3520 participants from 15 RCTs were included. VESW regimen increased the incidence of acute rejection (AR) over controls (RR = 1.46, CI = 1.20-1.79, p = 0.04). Subsequent analysis demonstrated that such difference lost significance in patients receiving tacrolimus (p = 0.16), but remained significant in patients with cyclosporin (p < 0.00001). The increased AR episodes were predominantly mild. VESW was associated with an increased incidence of delayed graft function (DGF) when steroids were withdrawn within three d post-transplantation. Cardiovascular risk factors, including incidence of new onset diabetes and total cholesterol, were significantly reduced under VESW regimen.

CONCLUSIONS

It is safe and practical to withdraw steroids very early after renal transplantation. However, a three- to seven-d course of steroids may decrease the risk for DGF relative to steroid withdrawal in <3 d. Antibody induction is effective in preventing early AR.

Use of the ImmuKnow assay to evaluate the effect of alemtuzumab-depleting induction therapy on cell-mediated immune function after renal transplantation

BACKGROUND

Good outcomes after renal transplantation are dependent on effective immunosuppression while minimizing infection. Alemtuzumab (Campath or Campath-1H) is an anti-CD52 humanized monoclonal IgG1 antibody which induces rapid and sustained depletion of circulating lymphocytes and has been effectively used as an immunosuppressant in post-transplant induction therapy.

METHODS

We used the ImmuKnow assay to compare cell-mediated immune function in renal transplant patients treated with alemtuzumab or with conventional immunosuppressive tri-therapy. The ImmuKnow method determines the levels of adenosine triphosphate (ATP) released from CD4 cells following stimulation with a mitogen.

RESULTS

We showed a statistically significant difference in the distribution of outcome after transplantation between the conventional and the Campath groups (P = 0.010). A significantly higher number of patients treated with alemtuzumab induction therapy were stable after transplantation compared to those treated with conventional immunosuppressive tri-therapy (96.6 vs. 75.7 %). ATP values were significantly higher in the conventional group compared to the Campath group at 180 days after transplantation (P < 0.001). ATP levels did not change significantly over time in clinically stable kidney recipients treated with alemtuzumab induction therapy (P = 0.554).

CONCLUSIONS

The ImmuKnow assay is a useful tool for evaluating the global immune response in alemtuzumab-treated renal transplant patients. Alemtuzumab-depleting induction therapy remains effective for at least 180 days.

Current state of renal transplant immunosuppression: Present and future

For kidney transplant recipients, immunosuppression commonly consists of combination treatment with a calcineurin inhibitor, an antiproliferative agent and a corticosteroid. Many medical centers use a sequential immunosuppression regimen where an induction agent, either an anti-thymocyte globulin or interleukin-2 receptor antibody, is given at the time of transplantation to prevent early acute rejection which is then followed by a triple immunosuppressive maintenance regimen. Very low rejection rates have been achieved at many transplant centers using combinations of these agents in a variety of protocols. Yet, a large number of recipients suffer chronic allograft injury and adverse events associated with drug therapy. Regimens designed to limit or eliminate calcineurin inhibitors and/or corticosteroid use are actively being pursued. An ideal immunosuppressive regimen limits toxicity and prolongs the functional life of the graft. This article contains a critical analysis of clinical data on currently available immunosuppressive strategies and an overview of therapeutic moieties in development.

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.