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

Heat shock protein 90 is a new potential target of anti-rejection therapy in allotransplantation

The critical roles of heat shock protein 90 (HSP90) in immune reactions associated with viral infection and autoimmune disease are well known. To date, however, its roles in the alloimmune response and the immunosuppressive effect of HSP90 inhibitors in allotransplantation have remained unknown. The purpose of this study was to examine the therapeutic efficacy of the HSP90 inhibitor 17-DMAG in allotransplantation models. C57BL/6 (H-2b) and BALB/c (H-2d) mice were used as donors for and recipients of skin and heart transplantation, respectively. Treatment with 17-DMAG (daily i.p.) or a vehicle was initiated 3 days before transplantation. Immunological outcomes were assessed by histopathological examinations, flow cytometric analysis, quantitative RT-PCR, ELISA, ELISPOT assay, and MLR. 17-DMAG treatment significantly prolonged the survival of both skin and heart allografts. In 17-DMAG-treated mice, donor-reactive splenocytes producing IFN-γ were significantly reduced along with the intragraft mRNA expression level and serum concentration of IFN-γ. Intragraft mRNA expression of cytokines and chemokines associated with both innate and adaptive immunity was suppressed in 17-DMAG-treated group. MLR showed suppression of the donor-specific proliferation of CD4 + T and CD19 + B cells in the spleens of 17-DMAG-treated mice. 17-DMAG treatment also reduced the number of activated NK cells. Furthermore, the treatment lowered the titers of donor-specific antibodies in the serum and prolonged a second skin allograft in mice sensitized by previous skin transplantation. HSP90 inhibition by 17-DMAG can affect various immune responses, including innate immunity, adaptive immunity, and humoral immunity, suggesting its therapeutic potential against acute rejection in allotransplantation.

Long-Term Outcomes of Kidney Transplant Recipients with Glomerulonephritides by Induction Type and Steroid Avoidance

Kidney transplant programs have different approaches to induction immunosuppression, and conflicting data exist on the role of steroid maintenance in recipients with glomerulonephritis (GN). GN patients are unique because of a higher risk for immune system exhaustion due to prior exposure to immunosuppressants to treat their GN; this raises questions regarding the optimal immunosuppression needed for transplant success and reduction of complications. We sought to assess the effect of induction type and steroid maintenance on the recipient and kidney graft survival in those with IgA nephropathy (IgAN), systemic lupus erythematosus related GN (SLE), small-vessel vasculitis (SVV), and anti-glomerular basement membrane disease (anti-GBM). We analyzed the Scientific Registry of Transplant Recipients (SRTR) database for adult, primary kidney recipients with the above glomerulonephritides through September 2019. Kaplan–Meier curves were generated to examine kidney graft and recipient survival. We used multivariable Cox proportional hazard models to investigate the impact of induction type and steroid maintenance in each group separately. Our study included 9176 IgAN, 5355 SLE, 1189 SVV, and 660 anti-GBM recipients. Neither induction type nor steroid maintenance therapy influenced recipient or death-censored graft survival in this cohort of recipients. Our findings provide an opportunity for recipients with a history of one of the studied glomerulonephritides to receive a more tailored immunosuppression regimen, considering their previous exposure to immunosuppressants.

Corticosteroids in Immunosuppression

Corticosteroids have been utilized as mainstay pharmacological intervention for successful organ transplantation since the beginning. Several challenges exist in establishing a balance between achieving a tolerant atmosphere in the host immune system while minimizing the long-term impact of steroids on the body. Corticosteroids are used early in all solid organ transplantation but there is wide variability across various organs and centers in the duration of use and protocols of planned steroid wean. The adverse event profile of steroids is exhaustive and across many organ systems.

Remote versus early corticosteroid wean outcomes in heart transplant recipients in the contemporary era

PURPOSE

The risks and benefits of remote corticosteroid weaning in heart transplant recipients more than 2 years post-transplant are unknown. We compared outcomes in patients undergoing early and remote steroid weaning after heart transplantation.

METHODS

We performed a retrospective study (range 09, 1991-04, 2017). Primary outcomes included short-term and long-term mortality, allograft dysfunction, and burden of rejection. Secondary outcomes included impact on hemoglobin A1c, lipid panel, bone scan T-score, and body mass index.

RESULTS

63 patients underwent corticosteroid weaning between 2012 and 2017. Outcomes of patients weaned early (n = 34; median time from transplant = 1.1 years) were compared with those weaned late (n = 29; median time from transplant = 4.4 years). 52 (82.5%) patients were successfully weaned off corticosteroids. No statistically significant difference in outcomes was found between the early and late weaning groups (p = .20). There were no differences in allograft function (p-value = .16), incidence of rejection (p = .46), or mortality (p = .15). Improvement in metabolic profile was seen in both groups but was not statistically significant.

CONCLUSIONS

In heart transplant recipients, remote vs early weaning of corticosteroids is not associated with significant differences in graft function or the incidence of rejection after 1-year follow-up. Moreover, there were no significant differences in survival up to 3 years between the two groups.

Induced Intermediate Mesoderm Combined with Decellularized Kidney Scaffolds for Functional Engineering Kidney

Background

Chronic kidney disease is a severe threat to human health with no ideal treatment strategy. Mature mammalian kidneys have a fixed number of nephrons, and regeneration is difficult once they are damaged. For this reason, developing an efficient approach to achieve kidney regeneration is necessary. The technology of the combination of decellularized kidney scaffolds with stem cells has emerged as a new strategy; however, in previous studies, the differentiation of stem cells in decellularized scaffolds was insufficient for functional kidney regeneration, and many problems remain.

Methods

We used 0.5% sodium dodecyl sulfate (SDS) to produce rat kidney decellularized scaffolds, and induce adipose-derived stem cells (ADSCs) into intermediate mesoderm by adding Wnt agonist CHIR99021 and FGF9 in vitro. The characteristics of decellularized scaffolds and intermediate mesoderm induced from adipose-derived stem cells were identified. The scaffolds were recellularized with ADSCs and intermediate mesoderm cells through the renal artery and ureter. After cocultured for 10 days, cells adhesion and differentiation was evaluated.

Results

Intermediate mesoderm cells were successfully induced from ADSCs and identified by immunofluorescence and Western blotting assays (OSR1 + , PAX2 +). Immunofluorescence showed that intermediate mesoderm cells differentiated into tubular-like (E-CAD + , GATA3 +) and podocyte-like (WT1 +) cells with higher differentiation efficiency than ADSCs in the decellularized scaffolds. Comparatively, this phenomenon was not observed in induced intermediate mesoderm cells cultured in vitro.

Conclusion

In this study, we demonstrated that intermediate mesoderm cells could be induced from ADSCs and that they could differentiate well after cocultured with decellularized scaffolds.

Characterizing pre-transplant and post-transplant kidney rejection risk by B cell immune repertoire sequencing

Studying immune repertoire in the context of organ transplant provides important information on how adaptive immunity may contribute and modulate graft rejection. Here we characterize the peripheral blood immune repertoire of individuals before and after kidney transplant using B cell receptor sequencing in a longitudinal clinical study. Individuals who develop rejection after transplantation have a more diverse immune repertoire before transplant, suggesting a predisposition for post-transplant rejection risk. Additionally, over 2 years of follow-up, patients who develop rejection demonstrate a specific set of expanded clones that persist after the rejection. While there is an overall reduction of peripheral B cell diversity, likely due to increased general immunosuppression exposure in this cohort, the detection of specific IGHV gene usage across all rejecting patients supports that a common pool of immunogenic antigens may drive post-transplant rejection. Our findings may have clinical implications for the prediction and clinical management of kidney transplant rejection.

Causes of late transplant failure in cyclosporine-treated kidney allograft recipients

BACKGROUND

There is little information about very long-term outcomes of kidney allograft recipients exposed to calcineurin inhibitors.

METHODS

In this single-centre retrospective study with 20-year follow-up, we analyzed data from 644 patients who underwent primary renal transplantation between 1983 and 1993. Participants were treated with a cyclosporine-based immunosuppressive scheme and had allograft function at 1 year.

RESULTS

After 20 years, 15.2% patients died, 39.7% experienced allograft loss, 26.8% were alive with a functioning transplant, and 18.2% were lost to follow-up. Cardiovascular disease (30.8%), malignancy (26.6%) and infection (17.0%) were the main causes of death. Age, new-onset proteinuria > 1 g/day, major acute cardiovascular event (MACE), and malignancy were independent predictors of mortality at time-dependent multivariate analysis. Chronic rejection (63.3%), recurrent glomerulonephritis (14.0%), and nonspecific interstitial fibrosis/tubular atrophy (13.2%) were the leading cause of allograft loss. Basal disease, hepatitis C, difference between 1 year and nadir serum creatinine, new-onset proteinuria > 1 g/day, and MACE were independent predictors of transplant failure. Among patients with 20-year allograft function, we recorded the following complications: hypertension (85%), malignancy (13%), diabetes (9%), and cardiovascular disease (9%). Median serum creatinine and proteinuria were 1.4 mg/dL and 0.6 g/day, respectively.

CONCLUSIONS

Prolonged use of cyclosporine may expose to several dose-related adverse events and may contribute to the development of allograft dysfunction but it does not necessarily cause relentless, progressive transplant failure if patients are carefully and consistently monitored during the follow-up.

Graft outcomes following immunosuppressive therapy with different combinations in kidney transplant recipients: a nationwide cohort study

Background

Immunosuppression plays an essential role to overcome immune-related allograft rejection, but it also causes some nephrotoxicity. This study aimed to investigate how the immunosuppressant combinations affect graft outcomes in kidney transplant recipients.

Methods

A nationwide population-based cohort study using the Taiwan National Health Insurance Database was conducted. A total of 3,441 kidney transplant recipients who underwent kidney transplantation during the targeted period were included. The effects on graft outcomes contributed by conventional immunosuppressants, including corticosteroid, calcineurin inhibitors, antimetabolite purine antagonists, and mammalian target of rapamycin inhibitors, were compared.

Results

A total of 423 graft failures developed after the index date. Therapy regimens incorporated with purine antagonists had a comparable reduction of graft failure among four main drug groups regardless of whether they were given as monotherapy or in combination (adjusted hazard ratio: 0.52, 95% confidence interval: 0.42–0.63). Corticosteroid was found to have inferior effects among four groups (adjusted hazard ratio: 1.67, 95% confidence interval: 1.28–2.21). Furthermore, all 15 arrangements of mutually exclusive treatment combinations were analyzed by referencing with corticosteroid monotherapy. As referenced with steroid-based treatment, regimens incorporated with purine antagonists all have superior advantage on graft survival regardless of whether given in monotherapy (65% of graft failure reduced), dual therapy (48%–67% reduced), or quadruple therapy (43% reduced). In all triple therapies, only corticosteroid combined with calcineurin inhibitor and purine antagonist demonstrated superior protection on graft survival (52% of graft failure reduced).

Conclusion

The results may recommend several superior regimens for contributing to graft survival, and for supporting a steroid-minimizing strategy in immunosuppression maintenance.

Soluble fibrinogen like protein 2 (sFGL2), the novel effector molecule for immunoregulation

Soluble fibrinogen-like protein 2 (sFGL2) is the soluble form of fibrinogen-like protein 2 belonging to the fibrinogen-related protein superfamily. It is now well characterized that sFGL2 is mainly secreted by regulatory T cell (Treg) populations, and exerts potently immunosuppressive activities. By repressing not only the differentiation and proliferation of T cells but also the maturation of dendritic cells (DCs), sFGL2 acts largely as an immunosuppressant. Moreover, sFGL2 also induces apoptosis of B cells, tubular epithelial cells (TECs), sinusoidal endothelial cells (SECs), and hepatocytes. This mini-review focuses primarily on the recent literature with respect to the signaling mechanism of sFGL2 in immunomodulation, and discusses the clinical implications of sFGL2 in transplantation, hepatitis, autoimmunity, and tumors.

The effective bioengineering method of implantation decellularized renal extracellular matrix scaffolds

End stage renal disease (ESRD) is a progressive loss of kidney function with a high rate of morbidity and mortality. Transplantable organs are hard to come by and hold a high risk of recipient immune rejection. We intended to establish a more effective and faster method to decellularize and recellularize the kidney scaffold for transplant and regeneration. We successfully produced renal scaffolds by decellularizing rat kidneys with 0.5% sodium dodecyl sulfate (SDS), while still preserving the extracellular matrix (ECM) 3D architecture, an intact vascular tree and biochemical components. We recellularized the kidney scaffolds with mouse embryonic stem (ES) cells that then populated and proliferated within the glomerular, vascular, and tubular structures. After in vivo implantation, these recellularized scaffolds were easily reperfused, tolerated blood pressure and produced urine with no blood leakage. Our methods can successfully decellularize and recellularize rat kidneys to produce functional renal ECM scaffolds. These scaffolds maintain their basic components, retain intact vasculature and show promise for kidney regeneration.

In vivo regeneration of renal vessels post whole decellularized kidneys transplantation

Nearly 50 million patients in China live with end-stage renal disease (ESRD), and only about 4000 patients may receive kidney transplantation. The purpose of this study was to investigate regeneration of renal vessels post whole decellularized kidneys transplantation in vivo. We decellularized kidneys of donor rats by perfusing a detergent through the abdominal aorta, yielding feasible extracellular matrix, confirmed for acellularity before transplantation. Based on the concept of using the body as a bioreactor, we orthotopically transplanted the kidney and ureter scaffolds in recipient rats, and found the regeneration of vessels including artery and vein in the renal sinus following a spontaneous recanalization. Although the findings only represent an initial step toward the ultimate goal of the generation of fully functional kidneys in vivo, these findings suggest that the body itself, as the bioreactor, is a viable strategy for kidney regeneration.

National Variation in Use of Immunosuppression for Kidney Transplantation: A Call for Evidence-Based Regimen Selection

Immunosuppression management in kidney transplantation has evolved to include an increasingly diverse choice of medications. Although informed by patient and donor characteristics, choice of immunosuppression regimen varies widely across transplant programs. Using a novel database integrating national transplant registry and pharmacy fill records, immunosuppression use at 6-12 and 12-24 mo after transplant was evaluated for 22 453 patients transplanted in 249 U.S. programs in 2005-2010. Use of triple immunosuppression comprising tacrolimus, mycophenolic acid or azathioprine, and steroids varied widely (0-100% of patients per program), as did use of steroid-sparing regimens (0-77%), sirolimus-based regimens (0-100%) and cyclosporine-based regimens (0-78%). Use of triple therapy was more common in highly sensitized patients, women and recipients with dialysis duration >5 years. Sirolimus use appeared to diminish over the study period. Patient and donor characteristics explained only a limited amount of the observed variation in regimen use, whereas center choice explained 30-46% of the use of non-triple-therapy immunosuppression. The majority of patients who received triple-therapy (79%), cyclosporine-based (87.6%) and sirolimus-based (84.3%) regimens continued them in the second year after transplant. This population-based study of immunosuppression practice demonstrates substantial variation in center practice beyond that explained by differences in patient and donor characteristics.

Immunosuppressant dose reduction and long-term rejection risk in renal transplant recipients with severe bacterial pneumonia

INTRODUCTION

Due to lifelong immunosuppression, renal transplant recipients (RTRs) are at risk of infectious complications such as pneumonia. Severe pneumonia results in respiratory failure and is life‑threatening. We aimed to examine the influence of immunosuppressant dose reduction on RTRs with bacterial pneumonia and respiratory failure.

METHODS

From January 2001 to January 2011, 33 of 1,146 RTRs at a single centre developed bacterial pneumonia with respiratory failure. All patients were treated using mechanical ventilation and aggressive therapies in the intensive care unit.

RESULTS

Average time from kidney transplantation to pneumonia with respiratory failure was 6.8 years. In-hospital mortality rate was 45.5% despite intensive care and aggressive therapies. Logistic regression analysis indicated that a high serum creatinine level at the time of admission to the intensive care unit (odds ratio 1.77 per mg/dL, 95% confidence interval 1.01-3.09; p = 0.045) was a mortality determinant. Out of the 33 patients, immunosuppressive agents were reduced in 17 (51.5%). We found that although immunosuppressant dose reduction tended to improve in-hospital mortality, this was not statistically significant. Nevertheless, during a mean follow-up period of two years, none of the survivors (n = 18) developed acute rejection or allograft necrosis.

CONCLUSION

In RTRs with bacterial pneumonia and respiratory failure, higher serum creatinine levels were a mortality determinant. Although temporary immunosuppressant dose reduction might not reduce mortality, it was associated with a minimal risk of acute rejection during the two-year follow-up. Our results suggest that early immunosuppressant reduction in RTRs with severe pneumonia of indeterminate microbiology may be safe even when pathogens are bacterial in nature.

Early corticosteroid avoidance in kidney transplant recipients receiving ATG-F induction: 5-year actual results of a prospective and randomized study

One hundred ninety-seven patients received anti-T-lymphocyte globulins Fresenius, mycophenolate mofetil and delayed cyclosporine, and were randomized to ≥6-month corticosteroids (+CS; n=99) or no CS (-CS; n=98). One- and five-year actual graft survival (censored for death) was 93.2% and 86.4% in the +CS group versus 94.9% and 89.8% in the -CS group (5-year follow-up, p=0.487). Freedom from clinical rejection was 86.9% and 81.8% versus 74.5% and 74.5% (p=0.144), respectively, at 1 and 5 years; 5-year freedom from biopsy-proven rejection was 88.9% versus 83.7% (p=0.227). More late first rejections occurred in the +CS group. Significantly lower 5-year graft survival in patients experiencing rejection was observed for +CS (55.6% vs. 92.0%; p=0.005) with 8/18 versus 2/25 graft losses. Renal function at 5 years was stable and comparable (median serum creatinine, 159 vs. 145 µmol/L; creatinine clearance, 53.5 vs. 56.6 mL/min). More +CS patients developed diabetes, dyslipidemia and malignancies. Rejections in -CS patients occurred early after transplantation and did not impair long-term renal function. In patients receiving CS, rejections occurred later and with a higher risk for subsequent graft failure. A similar and not inferior 5-year efficacy profile and a reduced morbidity were observed in CS-free patients compared to patients who received CS for at least 6 months.

Three-year outcomes in kidney transplant patients randomized to steroid-free immunosuppression or steroid withdrawal, with enteric-coated mycophenolate sodium and cyclosporine: the infinity study

In a six-month, multicenter, open-label trial, de novo kidney transplant recipients at low immunological risk were randomized to steroid avoidance or steroid withdrawal with IL-2 receptor antibody (IL-2RA) induction, enteric-coated mycophenolate sodium (EC-MPS: 2160 mg/day to week 6, 1440 mg/day thereafter), and cyclosporine. Results from a 30-month observational follow-up study are presented. Of 166 patients who completed the core study on treatment, 131 entered the follow-up study (70 steroid avoidance, 61 steroid withdrawal). The primary efficacy endpoint of treatment failure (clinical biopsy-proven acute rejection (BPAR) graft loss, death, or loss to follow-up) occurred in 21.4% (95% CI 11.8–31.0%) of steroid avoidance patients and 16.4% (95% CI 7.1–25.7%) of steroid withdrawal patients by month 36 (P = 0.46). BPAR had occurred in 20.0% and 11.5%, respectively (P = 0.19). The incidence of adverse events with a suspected relation to steroids during months 6–36 was 22.9% versus 37.1% (P = 0.062). By month 36, 32.4% and 51.7% of patients in the steroid avoidance and steroid withdrawal groups, respectively, were receiving oral steroids. In conclusion, IL-2RA induction with early intensified EC-MPS dosing and CNI therapy in de novo kidney transplant patients at low immunological risk may achieve similar three-year efficacy regardless of whether oral steroids are withheld for at least three months.

Kidney transplantation with early corticosteroid withdrawal: paradoxical effects at the central and peripheral skeleton

The use of early corticosteroid withdrawal (ECSW) protocols after kidney transplantation has become common, but the effects on fracture risk and bone quality are unclear. We enrolled 47 first-time adult transplant recipients managed with ECSW into a 1-year study to evaluate changes in bone mass, microarchitecture, biomechanical competence, and remodeling with dual energy x-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HRpQCT), parathyroid hormone (PTH) levels, and bone turnover markers obtained at baseline and 3, 6, and 12 months post-transplantation. Compared with baseline, 12-month areal bone mineral density by DXA did not change significantly at the spine and hip, but it declined significantly at the 1/3 and ultradistal radii (2.2% and 2.9%, respectively; both P<0.001). HRpQCT of the distal radius revealed declines in cortical area, density, and thickness (3.9%, 2.1%, and 3.1%, respectively; all P<0.001), trabecular density (4.4%; P<0.001), and stiffness and failure load (3.1% and 3.5%, respectively; both P<0.05). Findings were similar at the tibia. Increasing severity of hyperparathyroidism was associated with increased cortical losses. However, loss of trabecular bone and bone strength were most severe at the lowest and highest PTH levels. In summary, ECSW was associated with preservation of bone mineral density at the central skeleton; however, it was also associated with progressive declines in cortical and trabecular bone density at the peripheral skeleton. Cortical decreases related directly to PTH levels, whereas the relationship between PTH and trabecular bone decreases was bimodal. Studies are needed to determine whether pharmacologic agents that suppress PTH will prevent cortical and trabecular losses and post-transplant fractures.

B-cell tolerance in transplantation: is repertoire remodeling the answer?

T lymphocytes are the primary targets of immunotherapy in clinical transplantation; however, B lymphocytes and their secreted alloantibodies are also highly detrimental to the allograft. Therefore, the achievement of sustained organ transplant survival will likely require the induction of B-lymphocyte tolerance. During development, acquisition of B-cell tolerance to self-antigens relies on clonal deletion in the early stages of B-cell compartment ontogeny. We contend that this mechanism should be recapitulated in the setting of alloantigens and organ transplantation to eliminate the alloreactive B-cell subset from the recipient. Clinically feasible targets of B-cell-directed immunotherapy, such as CD20 and B-lymphocyte stimulator (BLyS), should drive upcoming clinical trials aimed at remodeling the recipient B-cell repertoire.

Influence of steroid maintenance on the outcomes in deceased donor kidney transplant recipients experiencing delayed graft function

Delayed graft function (DGF) is a risk factor for poor long-term graft and patient survival after kidney transplantation. The aim of our study was to explore the beneficial effect of steroid maintenance on outcomes in deceased donor kidney (DDK) transplant recipients with DGF. Using organ procurement and transplant network/United network of organ sharing (OPTN/UNOS) database, we identified adult patients who developed DGF following DDK transplantation performed between January 2000 and December 2008. They received induction with rabbit antithymocyte globulin (r-ATG), alemtuzumab or an interluekin-2 receptor blocker (IL-2B) and were discharged on a calcineurin inhibitor (CNI)/mycophenolate (MMF) based immunosuppression with or without steroids. Adjusted graft and patient survivals were compared between steroid versus no steroid groups for each induction modality. Median follow-up was 29.6 months for the 10,058 patients who developed DGF. There were 5624 patients in r-ATG (steroid, n = 4569, no steroid, n = 1055), 819 in alemtuzumab (steroid, n = 301, no steroid, n = 518) and 3615 in IL-2B (steroid, n = 3380, no steroid, n = 235) groups. Adjusted graft survivals were similar for steroid versus no-steroid groups in patients who received r-ATG (HR: 0.98, 95% CI 0.85-1.13, P = 0.75), alemtuzumab (HR 0.88, 95% CI 0.65-1.19, P = 0.41), and IL-2B (HR 1.01, 95%CI 0.78-1.30, P = 0.96) inductions. The adjusted patient survivals were also similar in r-ATG (HR: 1.19, 95% CI 0.96-1.46, P = 0.19), alemtuzumab (HR: 0.89, 95% CI: 0.57-1.39, P = 0.96), and IL-2R (HR: 1.07, 95% CI: 0.77-1.49, P = 0.96) groups. Our study failed to show any significant graft or patient survival benefits associated with steroid addition to CNI/MMF regimen in DDK recipients with DGF. This may be related to the early immunogenic and non-immunogenic allograft damage from DGF with long-term consequences that are unaltered by steroids.

Physiological functions and clinical implications of fibrinogen-like 2: A review

Fibrinogen-like 2 (FGL2) encompasses a transmembrane (mFGL2) and a soluble (sFGL2) form with differential tertiary structure and biological activities. Typically, mFGL2 functions as prothrombinase that is capable of initiating coagulation in tissue without activation of the blood clotting cascade, whereas sFGL2 largely acts as an immunosuppressor that can repress proliferation of alloreactive T lymphocytes and maturation of bone marrow dendritic cells. Protein sequences of FGL2 exhibit evolutionary conservation across wide variety of species, especially at the carboxyl terminus that contains fibrinogen related domain (FRED). The FRED of FGL2 confers specificity and complexity in the action of FGL2, including receptor recognition, calcium affiliation, and substrate binding. Constitutive expression of FGL2 during embryogenesis and in mature tissues suggests FGL2 might be physiologically important. However, excessive induction of FGL2 under certain medical conditions (e.g., pathogen invasion) could trigger complement activation, inflammatory response, cellular apoptosis, and immune dysfunctions. On the other hand, complete absence of FGL2 is also detrimental as lack of FGL2 can cause autoimmune glomerulonephritis and acute cellular rejection of xenografts. All these roles involve mFGL2, sFGL2, or their combination. Although it is not clear how mFGL2 is cleaved off its host cells and secreted into the blood, circulating sFGL2 has been found correlated with disease severity and viral loading among patients with human hepatitis B virus or hepatitis C virus infection. Further studies are warranted to understand how FGL2 expression is regulated under physiological and pathological conditions. Even more interesting is to determine whether mFGL2 can fulfill an immunoregulatory role through its FRED at carboxyl end of the molecule and, and vice versa, whether sFGL2 is procoagulant upon binding to a target cell. Knowledge in this area should shed light on development of sFGL2 as an alternative immunosuppressive agent for organ transplantation or as a biomarker for predicting disease progression, monitoring therapeutic effects, and targeting FGL2 for repression in ameliorating fulminant viral hepatitis.

Recurrence of anti-neutrophil cytoplasmic antibody-associated vasculitis in appropriately immunosuppressed renal transplant patients: a discussion of two cases

Background

Granulomatosis with polyangiitis (GPA) (formerly known as Wegener's granulomatosis) is a multisystem autoimmune disease of unknown aetiology. Renal disease manifests as a crescentic glomerulonephritis, with varying degrees of renal failure. Ten percent of patients progress to end-stage kidney disease. Relapse of GPA in renal transplant patients is rare, with a rate of 0.09 relapses per patient per year.

Patients and Methods

We describe two cases of GPA relapse in immunosuppressed renal transplant patients.

Results

These patients presented with new-onset graft disfunction, having previously had an uncomplicated posttransplant course. Both patients were on appropriate doses of immunosuppressive agents at the time of relapse, with therapeutic target levels of tacrolimus. We describe the background history and management of both patients.

Conclusion

The cases described inform us that although recurrence of anti-neutrophil cytoplasmic antibody vasculitis in transplant patients is rare, it should remain on our list of differential diagnoses in allograft disfunction.

Decellularization methods of porcine kidneys for whole organ engineering using a high-throughput system

End-stage renal failure is a devastating disease, with donor organ transplantation as the only functional restorative treatment. The current number of donor organs meets less than one-fifth of demand, so regenerative medicine approaches have been proposed as potential therapeutic alternatives. One such approach for whole large-organ bioengineering is to combine functional renal cells with a decellularized porcine kidney scaffold. The efficacy of cellular removal and biocompatibility of the preserved porcine matrices, as well as scaffold reproducibility, are critical to the success of this approach. We evaluated the effectiveness of 0.25 and 0.5% sodium dodecyl sulfate (SDS) and 1% Triton X-100 in the decellularization of adult porcine kidneys. To perform the decellularization, a high-throughput system was designed and constructed. In this study all three methods examined showed significant cellular removal, but 0.5% SDS was the most effective detergent (<50 ng DNA/mg dry tissue). Decellularized organs retained intact microarchitecture including the renal vasculature and essential extracellular matrix components. The SDS-treated decellularized scaffolds were non-cytotoxic to primary human renal cells. This method ensures clearance of porcine cellular material (which directly impacts immunoreactivity during transplantation) and preserves the extracellular matrix and cellular compatibility of these renal scaffolds. Thus, we have developed a rapid decellularization method that can be scaled up for use in other large organs, and this represents a step toward development of a transplantable organ using tissue engineering techniques.

Reduced fracture risk with early corticosteroid withdrawal after kidney transplant

Corticosteroid use after kidney transplantation results in severe bone loss and high fracture risk. Although corticosteroid withdrawal in the early posttransplant period has been associated with bone mass preservation, there are no published data regarding corticosteroid withdrawal and risk of fracture. We hypothesized lower fracture incidence in patients discharged from the hospital without than with corticosteroids after transplantation. From the United States Renal Data System (USRDS), 77, 430 patients were identified who received their first kidney transplant from 2000 to 2006. Fracture incidence leading to hospitalization was determined from 2000 to 2007; discharge immunosuppression was determined from United Networks for Organ Sharing forms. Time-to-event analyses were used to evaluate fracture risk. Median (interquartile range) follow-up was 1448 (808-2061) days. There were 2395 fractures during follow-up; fracture incidence rates were 0.008 and 0.0058 per patient-year for recipients discharged with and without corticosteroid, respectively. Corticosteroid withdrawal was associated with a 31% fracture risk reduction (HR 0.69; 95% CI 0.59-0.81). Fractures associated with hospitalization are significantly lower with regimens that withdraw corticosteroid. As this study likely underestimates overall fracture incidence, prospective studies are needed to determine differences in overall fracture risk in patients managed with and without corticosteroids after kidney transplantation.

Ten-year outcome after rapid discontinuation of prednisone in adult primary kidney transplantation

BACKGROUND AND OBJECTIVES

Rapid discontinuation of prednisone after kidney transplantation potentially allows for minimization of steroid-related side effects. Although intermediate-term data with rapid discontinuation of prednisone have been promising, concern still exists regarding long-term outcomes. The 10-year experience is reported herein.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between October 1, 1999 and December 31, 2010, 1241 adult primary kidney transplants (791 living donor and 450 deceased donor) were performed using a protocol in which prednisone is discontinued after postoperative day 5. The 10-year actuarial recipient and graft survival rates and prednisone-related side effects were studied.

RESULTS

Ten-year actuarial patient survival was 71% for living donor transplants and 62% for deceased donor transplants; 10-year graft survival was 61% for living donor transplants and 51% for deceased donor transplants, and was comparable to 10-year Scientific Registry of Transplant Recipients national data. Ten-year death-censored graft survival was 79% for living donor transplants and 80% for deceased donor transplants. Ten-year acute rejection rates were 25% for deceased donor transplants and 31% for living donor transplants; 10-year chronic rejection (interstitial fibrosis/tubular atrophy) rates were 39% for deceased donor transplants and 47% for living donor transplants. For nondiabetic recipients of living donor or deceased donor allografts, the incidence of new-onset diabetes was significantly lower than in historical controls on prednisone (P<0.001). We also found significantly reduced rates of cataracts, avascular necrosis, and cytomegalovirus infection in some subgroups.

CONCLUSIONS

Prednisone-related side effects can be minimized in a protocol incorporating rapid discontinuation of prednisone for maintenance immunosuppression. Ten-year patient and graft outcomes remain acceptable.

Reduced fracture risk with early corticosteroid withdrawal after kidney transplant

Corticosteroid use after kidney transplantation results in severe bone loss and high fracture risk. Although corticosteroid withdrawal in the early posttransplant period has been associated with bone mass preservation, there are no published data regarding corticosteroid withdrawal and risk of fracture. We hypothesized lower fracture incidence in patients discharged from the hospital without than with corticosteroids after transplantation. From the United States Renal Data System (USRDS), 77, 430 patients were identified who received their first kidney transplant from 2000 to 2006. Fracture incidence leading to hospitalization was determined from 2000 to 2007; discharge immunosuppression was determined from United Networks for Organ Sharing forms. Time-to-event analyses were used to evaluate fracture risk. Median (interquartile range) follow-up was 1448 (808-2061) days. There were 2395 fractures during follow-up; fracture incidence rates were 0.008 and 0.0058 per patient-year for recipients discharged with and without corticosteroid, respectively. Corticosteroid withdrawal was associated with a 31% fracture risk reduction (HR 0.69; 95% CI 0.59-0.81). Fractures associated with hospitalization are significantly lower with regimens that withdraw corticosteroid. As this study likely underestimates overall fracture incidence, prospective studies are needed to determine differences in overall fracture risk in patients managed with and without corticosteroids after kidney transplantation.

Transplantation in diabetic kidney failure patients: modalities, outcomes, and clinical management

Diabetes mellitus (DM) is a common and devastating disease, affecting up to 19.3 million Americans. It is the leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in the United States. Diabetic patients with ESRD have a high incidence of cardiovascular disease and death. For those kidney transplant patients with no history of DM prior to transplantation, the development of new onset diabetes after transplantation (NODAT) also poses a serious threat to both graft and patient survival. Kidney transplantation is the best renal replacement option for diabetic ESRD and has the potential to halt the progression of cardiovascular diseases. Early referral for transplant evaluation is essential for pre-emptive or early kidney transplantation in this cohort of patients. In type 1 DM patients with ESRD, simultaneous pancreas and kidney transplantation (SPK) should be encouraged; and in patients facing prolonged waiting time for SPK transplantation but with an available living donor, living donor kidney transplantation followed by pancreas after kidney transplantation (PAK) is a suitable alternative. Islet transplantation in type 1 diabetics is deemed experimental by Medicare, and easy access to this modality remains restricted to qualified patients enrolled in clinical trials or with private insurance. The optimal management of kidney transplant patients with pre-existent DM or NODAT involves a multi-pronged approach consisting of pharmacological and nonpharmacological intervention to address all potential cardiovascular risk factors such as glycemic and lipid control, blood pressure control, weight loss, and smoking cessation. Finally, re-transplantation should be recommended in suitable kidney transplant patients when the kidney allograft demonstrates continuous and progressive decline in function.