Chronic Calcineurin Inhibitor Toxicity Research Articles

Skin cancer in solid organ transplant recipients: still an open problem.

In the last two decades, the optimization of organ preservation and surgical techniques, and the personalized immunosuppression have reduced the rate of acute rejections and early post-transplant complications. However, long-term graft survival rates have not improved over time, and evidence suggest a role of chronic calcineurin inhibitor toxicity in this failure. Solid organ transplant recipients may develop chronic dysfunction/damage and several comorbidities, including post-transplant malignancies. Skin cancers, mostly non-melanoma skin cancers (squamous cell carcinoma and basal cell carcinoma), are the most common malignancies in Caucasian solid organ transplant recipients. Several factors, together with immunosuppression, may contribute to the susceptibility for skin cancers which, although often treatable, could be associated with a much higher mortality rate than in the general population. The rapid identification and treatment (including reduction of immunosuppression and early surgical treatments) have an important role to avoid an aggressive behavior of these malignancies. Organ transplant recipients with a history of skin cancer should be followed closely for developing new and metastatic lesions. Additionally, patient education on the daily use of sun-protective measures and the recognition of the early signs (self-diagnosis) of coetaneous malignancies are useful preventive measures. Finally, clinicians should make themselves aware of the problem and build, in every clinical follow-up center, collaborative network involving transplant clinicians, dermatologists and surgeons who should work together to easily identify and rapidly treat these complications. In this review, we discuss the current literature regarding the epidemiology, risk factors, diagnosis, preventive strategies and treatments of skin cancer in organ transplantation.

Tacrolimus intrapatient variability in BK virus nephropathy and chronic calcineurin toxicity in kidney transplantation.

Intrapatient variability (IPV) in tacrolimus has been increasingly acknowledged as a risk factor for poor graft survival after kidney transplantation. Although past studies have mainly accounted for IPV in acute or chronic rejection states as due to underimmunosuppression, this is not yet clear. So far, tacrolimus IPV for BK virus-associated nephropathy (BKVN) and chronic calcineurin inhibitor toxicity (CNIT) has not been investigated. Here, we evaluated IPV in tacrolimus for BKVN and chronic CNIT, which are mainly considered as overimmunosuppression states. In this case-control study, kidney allograft biopsies conducted between 1998 and 2018 were included, with patients grouped by biopsy results as BKVN alone group, CNIT alone group, and normal graft function (control group). IPV was estimated as mean absolute deviation. Our study groups included 25 kidney transplant recipients with BKVN alone, 91 patients with CNIT alone, and 60 patients with normal 5-year graft survival (control group). In analyses of IPV in tacrolimus six months before graft biopsy, IPV was highest in the BKVN group (P = 0.001). The BKVN group also had the highest IPV in tacrolimus at 12 months after biopsy (P = 0.001), with all pairwise comparisons statistically different between groups. At 12 months after biopsy, five patients (20%) in the BKVN group and 10 patients (10.9%) in the CNIT group had graft loss. Among other risk factors, BKVN and chronic CNIT are consequences related to high IPV. Quantification of IVP for tacrolimus in clinical practice would help to optimize kidney transplant outcomes.

Diltiazem Böbrek Alıcılarında Greft Fonksiyonlarını İyileştirir mi?

Background: Acute and chronic calcineurin inhibitors (CNI) nephrotoxicity is a common concern in kidney transplant (KT) recipients. It is unclear whether diltiazem use can reduce CNI induced acute and chronic nephrotoxicity in (KT) recipients. In this study, we investigated the impact of diltiazem on 1 –year allograft survival and function.Materials and Methods: This single-center retrospective study included 312 kidney transplant recipients and donors. Diltiazem receiving and diltiazem-free recipients were compared for 1-year allograft survival and functions. Available allograft biopsies were investigated for the evidence pieces of CNI induced nephrotoxicity. Factors may have a potential impact on allograft functions were evaluated (cytomegalovirus and polyoma BK viremia positivity, acute rejection episodes, donors and recipients ages and body mass indexes). A statistical package program was used for data analysis. P<0.05 was assigned significant.Results: Seventy-three recipients in diltiazem arm and 239 in diltiazem-free arm were compared. In diltiazem and diltiazem-free arms, 1- year mortality, allograft survival rates and CNI induced nephrotoxicity incidences were 4.1% vs 3.8% (P=0.89), and 13.7% vs 7.1% (P=0.08), 18.8% vs 10.5% (P=0.27), respectively. However, 12-month estimated glomerular filtration rate was worse in diltiazem arm (62.75 ml/dk/1.73m2) compared to diltiazem-free group (73.19 ml/dk/1.73m2) (P=0.03). CNI toxicity had a weak impact on low eGFR in regression analysis (P=0.055 and 95% confidence interval).Conclusions: Despite diltiazem use allows to CNI dose reduction, it might have undesirable impacts on long-term allograft functions, which is the main target of the allograft care. Key Words: Allograft function, Diltiazem, Kidney transplantation

Proteomic Characterization of Urinary Extracellular Vesicles from Kidney-Transplanted Patients Treated with Calcineurin Inhibitors.

Use of immunosuppressive drugs is still unavoidable in kidney-transplanted patients. Since their discovery, calcineurin inhibitors (CNI) have been considered the first-line immunosuppressive agents, in spite of their known nephrotoxicity. Chronic CNI toxicity (CNIT) may lead to kidney fibrosis, a threatening scenario for graft survival. However, there is still controversy regarding CNIT diagnosis, monitoring and therapeutic management, and their specific effects at the molecular level are not fully known. Aiming to better characterize CNIT patients, in the present study, we collected urine from kidney-transplanted patients treated with CNI who (i) had a normal kidney function, (ii) suffered CNIT, or (iii) presented interstitial fibrosis and tubular atrophy (IFTA). Urinary extracellular vesicles (uEV) were enriched and the proteome was analyzed to get insight into changes happening during CNI. Members of the uroplakin and plakin families were significantly upregulated in the CNIT group, suggesting an important role in CNIT processes. Although biomarkers cannot be asserted from this single pilot study, our results evidence the potential of uEV as a source of non-invasive protein biomarkers for a better detection and monitoring of this renal alteration in kidney-transplanted patients.

Spectrum of renal allograft biopsy: A five-year experience at a tertiary care center of Eastern India

Renal allograft dysfunction (RAD) can have myriad causes and presentations. Allograft biopsy remains the gold standard for optimum management. This is a retrospective study carried out at a tertiary care institute from August 2011 to March 2016. Details of the renal allograft biopsy requisitions were recorded and analyzed. Two hundred and two patients had undergone kidney transplantation (KT) during the study period. One hundred and twenty-six had undergone renal biopsy for RAD. The acute asymptomatic rise of serum creatinine was the most common clinical presentation (47.61%) followed by chronic RAD (CRAD) (19.84%), proteinuria (15.87%), immediate graft dysfunction (10.31%), and persistent active urinary sediments (6.34%) in that order. The incidence of delayed graft function was 1.98%. The overall incidence of biopsy-proven rejection was 8.41% within oneyear and 8.91% beyond oneyear of transplant. Acute cellular rejection (ACR) [with or without antibody-mediated rejection (AMR)] was found in 65%; AMR was found in 40% and 15% had both ACR and AMR. Borderline acute cell-mediated rejection was found in 22.5% of biopsies. CRAD was due to chronic rejection and chronic calcineurin inhibitor toxicity in only about one-fourth of the cases. Incidence of glomerulo-nephritis was 10.89% and most of these occurred two years after KT. Renal allograft biopsy was associated with minor complications in 3.17% of cases. Clinical presentations do not reliably distinguish the various causes of RAD. Allograft biopsy is a mainstay in the diagnosis of RAD and is safe. Results of live donor first transplantation using complement-dependent cytotoxi-city crossmatch are comparable to those programs using newer methods like solid-phase assays. However, the direct comparison of these results with other studies may not be completely applicable.

Granular swollen epithelial cells in the kidney allograft: A clinicopathological study with special emphasis on possible marker for kidney allograft aging.

To elucidate the clinicopathological significance of granular swollen epithelial cells (GSECs), which provides histological evidence in the diagnosis of mitochondrial nephropathy, but incidentally observed in renal allografts, we evaluated GSECs as a surrogate histological marker for kidney allograft aging, as previously reported for p16, p21, and β-galactosidase. We retrospectively reviewed 426 kidney allograft biopsy specimens diagnosed at our university from January 2009 to April 2015. The prevalence and density of GSECs were compared with an age-matched control group of 508 native kidney biopsies. GSECs were defined as swollen (>2 times larger than normal renal tubular cells) epithelial cells best observed using Masson trichrome staining. Morphometric analyses were performed using digital microscopy software. The prevalence of GSECs was 7.7% in allograft kidneys and 8.1% in native kidneys. GSECs in kidney allografts were predominantly detected in medullary renal tubules, but not in the Bowman's capsular epithelium or podocytes. GSECs were observed in the following cases; no remarkable changes, n = 11; interstitial fibrosis and tubular atrophy, n = 7; chronic calcineurin inhibitor toxicity, n = 5; antibody-mediated rejection, n = 3; T cell-mediated rejection grade IA, n = 1; and others, n = 6. Compared with control specimens, medullary density of GSECs in kidney allografts was significantly increased. The prevalence of GSECs slightly increased with post-transplant duration; however, this trend was not statistically significant. The present study does not provide pathological significance of GSEC in kidney allografts in terms of allograft aging, and warrant the further research with molecular approach.

Is Th17 associated with fibrosis of chronic calcineurin inhibitor toxicity in renal transplant recipients?

Is Th17 associated with fibrosis of chronic calcineurin inhibitor toxicity in renal transplant recipients?

Antibody-mediated rejection: analyzing the risk, proposing solutions.

Antibody-mediated rejection: analyzing the risk, proposing solutions.

Sirolimus Immunoprophylaxis and Renal Histological Changes in Long-Term Cardiac Transplant Recipients: A Pilot Study.

The effects of sirolimus (SIR), as a substitution for calcineurin inhibitor (CNI) immunoprophylaxis, on renal function in very-long-term cardiac transplant recipients have been a matter of controversy. To assess the impacts of SIR as a substitution for CNI on renal function up to 24 months in long-term cardiac recipients as well as the renal histological changes in patients with suspected CNI-induced nephrotoxicity. A total of 23 cardiac transplant recipients aged 57.7 ± 11.2 years, 91 months post-cardiac transplantation were recruited; 15 patients were randomized to CNI-free immune suppression with SIR, and 8 patients were allocated to continue their CNI regimens. Serum creatinine and calculated serum creatinine clearance were measured at prespecified time points up to 24 months. Renal structure and function were assessed by renal biopsies, renal ultrasound, and magnetic resonance imaging at baseline. There were no significant changes in creatinine clearance during the course of the study in patients treated with SIR. However, SIR-treated patients exhibited a significant decrease in 24-hours and nighttime systolic and diastolic blood pressures. Typical findings of significant hypertensive renal disease were detected in 9 of the 11 (82%) patients. Features of chronic CNI toxicity were detected in 6 (55%) patients. There is a very high rate of hypertensive renal disease concomitantly with some degree of CNI toxicity in long-term cardiac transplant recipients with renal dysfunction. This very high rate of hypertension-related disease may limit the impact of SIR on improving renal function long term following cardiac transplantation.

Calcineurin inhibitor sparing strategies in renal transplantation, part one: Late sparing strategies.

Kidney transplantation improves quality of life and reduces the risk of mortality. A majority of the success of kidney transplantation is attributable to the calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, and their ability to reduce acute rejection rates. However, long-term graft survival rates have not improved over time, and although controversial, evidence does suggest a role of chronic CNI toxicity in this failure to improve outcomes. Consequently, there is interest in reducing or removing CNIs from immunosuppressive regimens in an attempt to improve outcomes. Several strategies exist to spare calcineurin inhibitors, including use of agents such as mycophenolate mofetil (MMF), mycophenolate sodium (MPS), sirolimus, everolimus or belatacept to facilitate late calcineurin inhibitor withdrawal, beyond 6 mo post-transplant; or using these agents to plan early withdrawal within 6 mo; or to avoid the CNIs all together using CNI-free regimens. Although numerous reviews have been written on this topic, practice varies significantly between centers. This review organizes the data based on patient characteristics (i.e., the baseline immunosuppressive regimen) as a means to aid the practicing clinician in caring for their patients, by matching up their situation with the relevant literature. The current review, the first in a series of two, examines the potential of immunosuppressive agents to facilitate late CNI withdrawal beyond 6 mo post-transplant, and has demonstrated that the strongest evidence resides with MMF/MPS. MMF or MPS can be successfully introduced/maintained to facilitate late CNI withdrawal and improve renal function in the setting of graft deterioration, albeit with an increased risk of acute rejection and infection. Additional benefits may include improved blood pressure, lipid profile and serum glucose. Sirolimus has less data directly comparing CNI withdrawal to an active CNI-containing regimen, but modest improvement in short-term renal function is possible, with an increased risk of proteinuria, especially in the setting of baseline renal dysfunction and/or proteinuria. Renal outcomes may be improved when sirolimus is used in combination with MMF. Although data with everolimus is less robust, results appear similar to those observed with sirolimus.

Challenges and considerations in diagnosing the kidney disease in deteriorating graft function

SummaryDespite significant reductions in acute-rejection rates with the introduction of calcineurin inhibitor (CNI)-based immunosuppressive therapy, improvements in long-term graft survival in renal transplantation have been mixed. Improving long-term graft survival continues to present a major challenge in the management of kidney-transplant patients. CNIs are a key component of immunosuppressive therapy, and chronic CNI toxicity has been widely thought to be a major factor in late graft failure. However, recent studies examining the causes of late graft failure in detail have challenged this view, highlighting the importance of antibody-mediated rejection and other factors. In addition, the diagnosis of CNI nephrotoxicity represents a challenge to clinicians, with the potential for over-diagnosis and an inappropriate reduction in immunosuppressive therapy. When graft function is deteriorating, accurately determining the cause of the kidney disease is essential for effective long-term management of the patient. Diagnosis requires a thorough clinical investigation, and in the majority of cases a specific cause can be identified.

Accompanying Renal Injuries Did Not Impact Graft Survival in Patients With Transplant Glomerulopathy

Transplant glomerulopathy (TG) a morphological feature of chronic active antibody-mediated rejection, is associated with donor-specific antibody, peritubular capillary deposition of C4d, and multilayering of peritubular capillary basement membranes. To evaluate the significance of accompanying nonimmunologic injuries in TG, we retrospectively reviewed 2839 renal allograft cases at our institute among which TG was diagnosed in 81 patients (2.9%). Among TG cases, 48 samples showed accompanying diseases such as chronic calcineurin inhibitor toxicity, hepatitis viral infection, posttransplant diabetes, and glomerulonephritis. Comparing the pure form of TG with TG-mixed diseases, there was no difference in patient demography, serum creatinine values, and proteinuria. Among histological parameters, severe hyalinosis was more frequently observed among the TG plus other diseases group. The two groups did not show significant difference in graft survival (P = .216).

Arteriolar Lesions in Renal Transplant Biopsies: Prevalence, Progression, and Clinical Significance

Arteriolar hyalinosis in kidney transplants is considered the histopathologic hallmark of chronic calcineurin inhibitor (CNI) toxicity. However, the lesion is not specific. We assessed prevalence, progression, and clinical significance of arteriolar lesions in 1239 renal transplant sequential protocol biopsy samples and 408 biopsy for cause samples in 526 patients. Associations between arteriolar lesions and presumed risk factors, concomitant histopathologic lesions, demographic factors, and graft function were evaluated. The frequency of arteriolar lesions was stable during the first 2 years after transplantation, and increased thereafter (14.8% at 6 months versus 48.6% at >2 years; P < 0.0001). We were unable to find associations with diabetes, hypertension, or CNI therapy. However, patients with early arteriolar lesions received grafts from older donors (mean ± SD age, 54.4 ± 13.4 years versus 43.1 ± 16.6 years; P < 0.0001), and had inferior graft function (estimated glomerular filtration rate 55 ± 21 mL/min versus 63 ± 24 mL/min at 6 weeks, 53 ± 19 mL/min versus 60 ± 23 mL/min at 1 year, and 49 ± 19 mL/min versus 59 ± 22 mL/min at 2 years; P < 0.05). Evaluation of late biopsy samples from patients not receiving CNI therapy revealed a high prevalence of AH without clear-cut identifiable underlying cause. Reproducibility of arteriolar lesions was at best moderate (κ ≤ 0.62). Sampling error in sequential biopsy samples was frequent. In conclusion, in samples from sequential protocol biopsies and biopsies for cause in individual patients, arteriolar lesions in renal transplants not only increase over time without being specific for CNI toxicity but are affected by sampling error and limited reproducibility.

Chronic Kidney Disease After Nonrenal Solid Organ Transplantation

It is proposed that chronic calcineurin inhibitor (CNI) nephrotoxicity has a central role in chronic kidney disease after nonrenal solid organ transplantation (NRSOT), although there are little data on renal histology in this setting. The aim of this study was to assess the histological features and renal outcomes of a cohort of patients with chronic kidney disease after NRSOT. Renal biopsies of 62 NRSOT recipients were evaluated for histological diagnoses. Biopsies were graded for chronic allograft damage index parameters and for arteriolar hyalinosis. The sum of all chronic allograft damage index parameters and arteriolar hyalinosis scores was called chronic damage index. The biopsies were performed at a median of 4 (range: 0.3-15.9) years after NRSOT and at serum creatinine of 318±17.7 μmol/L (mean±standard deviation). Twenty-two (35.5%) biopsies showed predominant features of chronic CNI nephrotoxicity, 27 (43.5%) predominant features of hypertensive nephropathy, and 12 (19.3%) an alternative primary renal pathology. Twenty-four (38.7%) patients had progression to end-stage renal disease, at a median of 1.5 (0-10.1) years after biopsy and 6.9 (0.3-19.2) years after NRSOT. The risk of renal progression was associated with in situ damage measured by chronic damage index. Although CNI nephrotoxicity is an important cause of renal failure after NRSOT, many patients do not have overt histological evidence of CNI toxicity. Quantitative parameters of chronic damage can stratify renal prognosis.

Chronic Calcineurin Inhibitor Nephrotoxicity—Lest We Forget

Calcineurin inhibitor (CNI) nephrotoxicity was recognized in Cambridge in the late 1970s. The vasoconstrictor impact of cyclosporine (CsA) and to a lesser extent tacrolimus, in both acute and chronic settings, results from a decrease in vasodilators and increase in vasconconstrictors while direct tubular toxicity results from blockade of mitochondrial permeability transition pores and inhibition of prolyl isomerase. A biopsy of native kidneys of recipients of CNIs reveals nephrotoxicity as the most common pathological diagnosis with chronic CNI toxicity and hypertension the primary problems. A long-term study of randomized clinical trials with up to 20 years of follow-up shows inferiority of both renal function and graft survival for continuous CsA compared to either CsA withdrawal or continuous azathioprine and prednisolone. Pathological hallmarks of chronic CNI nephrotoxicity include stripped interstitial fibrosis, arteriolar hyalinosis and glomerular sclerosis, but with the exception of nodular arteriolar hyalinosis the findings are non specific. The model for chronic renal allograft loss must be multifactorial with both immune and nonimmune factors operating dependent upon an individual's risk factors for cell and/or antibody-mediated rejection, CNI nephrotoxicity and recurrent disease. Better outcomes will require early diagnosis and individualization of therapy dependent upon the dominant mechanisms impacting each patient. The revisionist view put forward by some senior, experienced and thoughtful individuals, challenges the concept of chronic CNI nephrotoxicity as an important clinical entity. By implication, the view that appears to be promoted is as follows: we need not fear-prolonged exposure to CNIs, and in seeking better long-term solutions for transplant recipients, we have forgotten alloimmunity. It is thus apparent that we must revisit the data and again question the basis for chronic CNI nephrotoxicity in current clinical practice. This contribution to the debate will focus on the evidence that CNIs are nephrotoxic and that their impact needs to be limited if we are to improve long-term outcomes after transplantation, leaving others to promote the contrary perspective and perhaps also to reflect on the largely unproven impact of the steroid avoidance and other minimization strategies so prevalent today.

Immunohistochemical characterization of glomerular and tubulointerstitial infiltrates in renal transplant patients with chronic allograft dysfunction

The term chronic allograft nephropathy (CAN) was deleted in the Eighth Banff Classification and two new categories were introduced: chronic T-cell-mediated rejection (CTMR) and chronic active humoral rejection (CAHR). The aim of this study was to revise our CAN cases diagnosed in the last 4 years, analyse allograft survival rates and identify types of infiltrating cells in the different settings. Seventy-nine patients with biopsy-proven CAN were examined and classified into four groups according to the Banff 2005 criteria: CTMR, CAHR, chronic calcineurin inhibitor toxicity (CNITOX) and interstitial fibrosis and tubular atrophy not otherwise specified (NOS). CD4, CD8, CD20, CD68, CD103, Foxp3 and IL-17 protein expression and C4d deposits were investigated. We diagnosed 20 CTMR, 13 CAHR, 28 CNITOX, and 18 NOS. Death-censored graft survival at 4 years from renal biopsy was worse in CAHR compared with the other types of chronic injury. Glomerular CD8(+) cells were increased in CTMR vs CNITOX and NOS. Interstitial CD4(+) and CD8(+) cells were increased in CTMR vs CNITOX. CD68(+) cells in glomerular and peritubular capillaries were higher in CAHR vs CNITOX, CTMR and NOS. CD103(+) cells were higher in cases with tubulitis than in those without. T regulatory and T helper 17 cells were rarely observed in the different settings. Graft survival was worse in patients with CAHR. The presence of any grade transplant glomerulopathy and chronic allograft vasculopathy are poorer prognostic factors. Infiltrating CD8(+), CD103(+) and CD4(+) cells may help to differentiate CTMR from other types of chronic injury, thus improving diagnostic/prognostic features of biopsy in patients with chronic allograft dysfunction.

Allograft Biopsies

Advances in short-term renal allograft survival, as a result in large part of the use of calcineurin inhibitors (CNIs), have not translated into increased organ longevity.1 For decades, researchers have tried to uncover the pathogenesis of chronic graft failure using histopathologic examination of human biopsies. Despite these efforts, biopsy evaluation in the setting of chronic graft failure is often a frustrating experience for nephrologist and nephropathologist alike. There is consensus that the most frequent biopsy findings in long-term graft failure (censored for death) result from cumulative injuries to the graft, which produce a pathologic pattern of scarring involving all renal compartments.2 Controversy over the term used to describe these findings (chronic allograft nephropathy versus interstitial fibrosis and tubular atrophy (IF/TA) is less important than the recognition that the dominant changes seen by routine microscopy represent a nonspecific common injury pathway, not a diagnosis, and that in most of those biopsies we lack the ability to determine the underlying cause.3 There are many reasons for this imprecision, such as preexisting structural damage, the effects of comorbid conditions, and the structure/function interdependence of the renal compartments. Furthermore, comparisons across time and place are limited by the fact that every biopsy bears the imprint of the patient's individual immunosuppression protocol. Nevertheless, significant progress has been made in identifying many of the underlying processes, and donor age and chronic CNI toxicity both emerge as major nonimmunologic factors.4–6 Distinguishing the histopathology of these two processes from other causes of chronic injury, as well as from each other, is difficult, particularly in …

Minimizing the Risk of Chronic Allograft Nephropathy

Chronic allograft nephropathy, now defined as interstital fibrosis and tubular atrophy not otherwise specified, is a near universal finding in transplant kidney biopsies by the end of the first decade posttransplantation. After excluding death with functioning graft, caused by cardiovascular disease or malignancy, chronic allograft nephropathy is the leading cause of graft failure. Original assumptions were that this was not a modifiable process but inexorable, likely due to past kidney injuries. However, newer understandings suggest that acute or subacute processes are involved, and with proper diagnosis, appropriate interventions can be instituted. Our method involved a review of the primary and secondary prevention trials in calcineurin inhibitor withdrawal. Some of the more important causes of progressive graft deterioration include subclinical cellular or humoral rejection, and chronic calcineurin inhibitor toxicity. Early graft biopsy, assessment of histology, and changes in immunosuppression may be some of the most important measures available to protect graft function. The avoidance of clinical inertia in pursuing subtle changes in graft function is critical. Modification in maintenance immunosuppression may benefit many patients with early evidence of graft deterioration.

Late Conversion From Calcineurin Inhibitor–Based to Sirolimus-Based Immunosuppression Due to Chronic Toxicity: A Prospective Study With Protocol Biopsy Amendment

Background There is an emerging consensus on conversion from calcineurin inhibitor (CNI)-based regimens to proliferation signal inhibitor (PSI)-based protocols for the prevention of a progressive decline in graft function due to CNI toxicity. Methods Thirty-one primary renal transplant recipients within 17–48 years of age (mean, 32.2 ± 1.6) were enrolled in this dual-center study. Eligible patients had a baseline (pre-engraftment) biopsy and completed at least 12 months of follow-up with deteriorating graft function indicative of chronic CNI toxicity with or without nonspecific interstitial fibrosis/tubular atrophy (IF/TA) on a biopsy specimen. A fast conversion protocol, being defined as a 50% initial reduction followed by complete withdrawal of CNI drug within 2 weeks of introducing rapamycin was performed in all patients. A sirolimus (SRL) loading dose was not prescribed; all subjects directly received maintenance (2–5 mg/d) doses of the drug. The primary endpoint of this study was assessement of renal function using cGFR and renal histology by protocol biopsy at 1 year after conversion. Results The mean follow-up after conversion was 21.6 months. The difference between cGFR before compared with cGFR after 12 months after conversion (40.8 ± 2.36 mL/min vs 55.7 ± 3.6 mL/min; P < .000) and at the last follow-up (40.8 ± 2.36 mL/min vs 53.8 ± 2.96 mL/min; P < .000) was significant. The mean IF/TA with glomerulosclerosis and chronic vasculopathy scores of biopsy specimens at baseline, during conversion, and at 12 months of the study were 2.25 ± 0.3, 3.30 ± 0.24, and 3.0 ± 0.30, respectively. The change in scores was indicative of mild progression; however, the difference was not significant. IF/TA, glomerulosclerosis, and chronic vasculopathy scores improved in 8 (30%) subjects, remained unchanged in 11 (42%) and worsened in 7 (28%) after 1 year of SRL therapy. After conversion there was no patient or graft loss in this group. Moreover, SCr and GFR improved in 21 or 29 patients (72%), remained stable in 4 (14%), and decreased in 4 (14%) patients. The predictors of successful conversion in our study were GFR ≥ 40.6 mL/min, SCr ≤ 2.34 mg/dL, and histological allograft damage score ≤3. Conclusion SRL-MPA/MMF-ST combination may be a good therapeutic strategy against chronic CNI toxicity, particularly for patients whose conversion biopsy specimens demonstrated mild IF/TA, glomerulosclerosis, and chronic vasculopathy scores (≤3.1 ± 0.3).

Ahmedabad tolerance induction protocol and chronic renal allograft dysfunction: pathologic observations and clinical implications

BackgroundChronic Renal Allograft Dysfunction (CRAD) is responsible for a large number of graft failures. We have abrogated acute T-cell rejections using Ahmedabad Tolerance Induction Protocol (ATIP) with hematopoietic stem cell transplantation (HSCT) under non-myeloablative conditioning pre-transplant. However B-cell mediated rejections and CRAD continue to haunt us. We carried out retrospective analysis of renal allograft biopsies performed in the last 4 years to evaluate the effect of ATIP on CRAD.Materials and methodsBiopsies diagnosed as per modified Banff criteria belonged to 2 groups: ATIP under low dose immunosuppression of cyclosporine/Azathioprine/Mycofenolate mofetil+ Prednisolone, subjected to donor leucocyte transfusion, anti-T/B cell antibodies, low dose target specific irradiation, cyclophosphamide, cyclosporin followed by HSCT pre-transplant; controls who opted out of ATIP were transplanted under standard triple drug immunosuppression. Demographics of both groups were comparable.ResultsIncidence of chronic changes was higher in controls (17.5%) vs. 10.98% in ATIP over a mean follow up of 151.9 months in the former and 130.9 months in the latter. Proteinuria and hypertension were higher in controls (48.4%) vs. ATIP (32.7%) with chronic transplant glomerulopathy, focal global sclerosis in 67.7% in controls vs. 46.7% in ATIP, acute on chronic T/B cell rejection in 51.6% controls vs. 28.1% ATIP, with peritubular capillary C4d deposits in 19.4% controls vs. 1.9% ATIP biopsies. Acute on chronic calcineurin inhibitor toxicity was higher in ATIP (71.9%) vs. 48.4% in controls.ConclusionChronic immune injury was less with ATIP vs controls as compared to a higher incidence of chronic calcineurin inhibitor toxicity in the former.