Subclinical Rejection Episodes Research Articles

Clinical Value of Surveillance Biopsies in Pediatric Liver Transplantation.

Although pediatric liver transplantation (LT) results in excellent long-term outcomes, a high incidence of early acute cellular rejection and late graft fibrosis persists. Routine measurement of allograft enzymes may not reliably detect rejection episodes, identify candidates for immunosuppression minimization, or indicate allograft fibrosis. Surveillance biopsies (SBs) can provide valuable information in this regard, but their role in pediatric LT is not fully established. A retrospective cohort of 236 pediatric LT recipients from a high-volume center was studied to characterize the risks and benefits of SB versus for-cause biopsies (FCBs). The study population was 47.1% male and 54.7% Hispanic, and 31% received living donor grafts. Our data suggest that patients in the SB group had better transplant outcomes (rejection-free, graft, and patient survival) compared with patients who had FCBs or who never underwent biopsy. Among 817 biopsies obtained from 236 patients, 150 (18.4%) were SBs. Only 6 patients had a biopsy-related complication, and none were observed in the SB subset. Graft biochemical blood tests did not accurately predict rejection severity on biopsy, with aspartate aminotransferase area under the receiver operating characteristic curve (AUROC) 0.66, alanine aminotransferase AUROC 0.65 (very poor predictions), and gamma-glutamyltransferase AUROC 0.58 (no prediction). SBs identified subclinical rejection in 18.6% of biopsies, whereas 63.3% of SBs had evidence of fibrosis. SBs prompted changes in immunosuppression including dose reduction. Our experience suggests that SB in pediatric LT is safe, offers valuable information about subclinical rejection episodes, and can guide management of immunosuppression, including minimization. Improved outcomes with SB were likely multifactorial, potentially relating to a more favorable early posttransplant course and possible effect of management optimization through SB. Further multicenter studies are needed to examine the role of SBs on long-term outcomes in pediatric LT.

A Prospective Controlled Trial to Evaluate Safety and Efficacy of in vitro Expanded Recipient Regulatory T Cell Therapy and Tocilizumab Together With Donor Bone Marrow Infusion in HLA-Mismatched Living Donor Kidney Transplant Recipients (Trex001).

Background: The induction of donor-specific immunological tolerance could improve outcome after kidney transplantation. However, no tolerance protocol is available for routine clinical use. Chimerism-based regimens hold promise, but their widespread application is impeded in part by unresolved safety issues. This study tests the hypothesis that therapy with polyclonal recipient regulatory T cells (Tregs) and anti-IL6R (tocilizumab) leads to transient chimerism and achieves pro-tolerogenic immunomodulation in kidney transplant recipients also receiving donor bone marrow (BM) without myelosuppressive conditioning of the recipient.Methods/design: A prospective, open-label, controlled, single-center, phase I/IIa academic study is performed in HLA-mismatched living donor kidney transplant recipients.Study group: Recipients of the study group receive in vitro expanded recipient Tregs and a donor bone marrow cell infusion within 3 days after transplantation and tocilizumab for the first 3 weeks post-transplant. In addition they are treated with thymoglobulin, belatacept, sirolimus, and steroids as immunosuppression. Starting 6 months post-transplant, sirolimus and steroids are withdrawn in a step-wise manner in stable patients.Control group: Recipients of the control group are treated with thymoglobulin, belatacept, sirolimus, and steroids as immunosuppression. Co-primary endpoints of safety (impaired graft function [eGFR <35 mL/min/1.73 m2], graft-vs.-host disease or patient death by 12 months) and efficacy (total leukocyte donor chimerism within 28 days post-transplant) are assessed. Secondary endpoints include frequency of biopsy-proven acute rejection episodes and subclinical rejection episodes on surveillance biopsies, assessment of kidney graft function, and the evaluation whether the study protocol leads to detectable changes in the immune system indicative of pro-tolerogenic immune modulation.Discussion: The results of this trial will provide evidence whether treatment with recipient Tregs and donor BM is feasible, safe and efficacious in leading to transient chimerism. If successful, this combination cell therapy has the potential to become a novel treatment option for immunomodulation in organ transplantation without the toxicities associated with myelosuppressive recipient conditioning.Trial registration: European Clinical Trials Database EudraCT Nr 2018-003142-16 and clinicaltrials.gov NCT03867617.

Single center experience of subclinical rejections and BK nephropathies by kidney allografts’ surveillance biopsies

PurposeAcute rejection of the kidney allograft remains the most important factor affecting the long-term graft outcome and is a major predictor of development of chronic damage and graft loss. Several studies have shown that early detection and treatment of subclinical rejection episodes may be beneficial for the graft outcome. The role of protocol (surveillance) biopsies and the value of donor specific antibodies (DSA) monitoring are still debatable. MethodsThis is a prospective observational study involving seventeen kidney recipients transplanted in north-eastern part of Poland who underwent “zero”, 3-month and 12-month allograft biopsies as well as DSA assessment. ResultsHistologic analysis of the biopsies showed subclinical acute cellular rejection in 17.6% of patients (two tubulointerstitial, one vascular) at 3-months post transplantation, and additional case of borderline rejection at the 12-month point. Moreover, two cases (11.8%) of polyomavirus BK nephropathy were diagnosed (one at 3 and one at 12 month point). None of the patients developed de novo DSA. ConclusionsOur protocol biopsies allowed us to detect significant proportion of patients with subclinical, but histologically relevant acute cellular rejection and BK nephropathy. Early therapeutic intervention had beneficial effects in a 4-year follow up.

Uterus transplantation trial: 1-year outcome

To report the 12-month outcome of seven patients with viable uteri after uterus transplantation (UTx). Prospective observational study. University hospital. Seven patients with absolute uterine infertility and viable uteri for 12 months after live-donor UTx. Predetermined immunosuppression was with tacrolimus and mychophenolate mofetil (MMF) during 6 months, whereupon MMF should be withdrawn. Frequent ultrasound examinations were performed to assess uterine appearance and uterine artery blood flow. Cervical biopsies (for histological detection of rejection) were obtained at preset time points, with temporary adjustments of immunosuppression if there were signs of rejection. Menstruations were systematically recorded. Menstruation, uterine artery blood flow, histology of cervical biopsies, and blood levels of tacrolimus. All patients showed regular menses after 1-2 months. Uterine artery blood flow was unchanged, with a median pulsatility index of 1.9 (range, 0.5-5.4). Blood levels of tacrolimus were approximately 10, 9, and 8 (μg/L) during months 2, 9, and 12, respectively. Four recipients showed mild inflammation in biopsies after MMF withdrawal and were treated with corticosteroids and azathioprine during the remainder of the 12 months. Subclinical rejection episodes were detected on ectocervical biopsies in five recipients. Histology showed apoptotic bodies and occasional spongiosis in the squamous epithelium. Moderate infiltration of lymphocytes and neutrophils was seen in the epithelial/stromal interface. All rejection episodes were successfully treated for 2 weeks with corticosteroids or dose increments of tacrolimus. We demonstrate long-term uterine viability after UTx, with continued menstruation and unaltered uterine artery blood flow. Subclinical rejection episodes were effectively reversed by temporary increase of immunosuppression. NCT01844362.

Optimal Mycophenolic Acid and Mycophenolic Acid Glucuronide Levels at the Early Period After Kidney Transplantation Are the Key Contributors to Improving Long-Term Outcomes

Introduction Suboptimal mycophenolic acid (MPA) and its metabolite MPA glucuronide (MPAG) levels are associated with significant increased incidences of graft loss. This study assessed the influence of MPA and MPAG C 0 levels on glomerular filtration rate (GFR) values and histopathologic changes in protocol biopsies of kidney allograft recipients. Patients and methods This prospective study of 42 low-risk patients receiving mycophenolate mofetil, prednisone, and a low or normal cyclosporine dose included histological assessment, according to the Banff'97 classification, of protocol biopsies before and at 3, 12, and 36 months after transplantation, as well as GFR at 1, 3, 12, 36, and 60 months and MPA enzyme-linked immunosorbent assay, MPAG (HPLC/UV) C 0 levels at 7 days as well as at 1, 3, 12, and 36 months. Results We observed nonlinear, significant correlations between MPA, MPAG C 0 levels and subclinical rejection episodes (SCR) according to chronic interstitial changes (ci), chronic tubulitis (ct), arteriolar hyalinization (ah) and chronic allograph nephropathy (CAN) indices in protocol biopsies. MPA C 0 levels below 1.0 to 1.5 μg/mL at day 7 were associated with an increased risk of SCR ( P < .03), ci ≥ 2 ( P < .05), CAN ≥ 2 ( P < .04), and ah ≥ 2 ( P < .07). MPAG C 0 levels above 100 to 150 μg/mL at day 7 were associated with a decreased risk of ct ≥ 2 ( P < .01), ci ≥ 2 ( P < .04), or CAN ≥ 2 ( P < .04). We also observed a significant linear positive correlation between MPA C 0 level and a significant negative correlation between MPAG C 0 level at 1 month with GFR. Conclusion Optimal MPA and MPAG exposure in the early posttransplant period may improve renal graft outcomes.

No Difference in Degree of Interstitial Sirius Red–Stained Area in Serial Biopsies from Area under Concentration-over-Time Curves–Guided Cyclosporine versus Tacrolimus-Treated Renal Transplant Recipients at One Year

Interstitial fibrosis is the main characteristic of chronic allograft nephropathy and long-term graft failure. Cyclosporin (CsA) is thought to be more fibrogenic than tacrolimus. In a prospective, randomized, multicenter trial using a calcineurin-sparing regimen, renal interstitial volume was compared in CsA- and tacrolimus-treated renal transplant recipients by image analysis of Sirius red (SR)-stained cortical areas in protocol biopsies obtained at 6 mo (n = 94) and 12 mo (n = 97) after transplantation. Immunosuppression consisted of CsA or tacrolimus, CD25 mAb, mycophenolate mofetil, and prednisolone. CsA therapy increased the 6-mo risk for subclinical rejection. The prevalence of subclinical rejection was 38.8% in the CsA-treated and 15.2% in the tacrolimus-treated patient group (P = 0.012). Strikingly, no difference in the degree of interstitial SR-stained area was detectable between the two treatment groups. In particular, previous subclinical rejection episodes did not influence the degree of interstitial volume. Also, no difference in GFR occurred at 1 yr, when the mean GFR mounted 63 ml/min. No significant differences in the degree of interstitial SR-stained area could be observed at 6 and 12 mo between CsA- and tacrolimus-treated renal transplant recipients. Although CsA-treated patients developed significantly more subclinical rejections at 6 mo, this did not influence the degree of SR staining or the change in renal function at 1 yr.

αvβ6 integrin expression in diseased and transplanted kidneys

Integrins have been implicated in the pathogenesis of a diverse range of kidney diseases. Herein, we provide the first detailed description of an epithelial restricted integrin, alpha(v)beta(6), in kidney biopsies from patients suffering acute and chronic renal diseases and after transplantation. Immunoperoxidase staining for beta(6) was performed on 267 selected biopsy specimens from native (N= 126) and transplanted kidneys (N= 141) and scored semiquantitatively. The site of beta(6) expression in tubules was determined using haematoxylin counterstaining and by colocalization with Tamm-Horsfall protein. Comparisons were made between subcategories of diseases of native kidneys and between "service" and "protocol" biopsies of transplanted kidneys. beta(6), when present, is largely confined to the distal tubules and collecting ducts, colocated with Tamm-Horsfall protein. When sparsely present, it was often restricted to the tubular segment associated with the juxtaglomerular apparatus. It was found in tubular cells shed into the urine. beta(6) was not expressed in thin membrane nephropathy, or in nonproliferative forms of glomerulonephritis, with the exception of focal and segmental glomerulosclerosis (FSGS). It was diffusely expressed where there was glomerular necrosis or thrombosis and in most forms of acute or chronic tubulointerstitial disease. beta(6) was diffusely up-regulated in allografts biopsied for delayed function, in almost all kidneys that have clinical or subclinical rejection episodes and was prominent in chronic allograft nephropathy. beta(6) integrin is not normally expressed in adult native or transplanted kidneys but is commonly up-regulated in the distal tubule in disease. Our descriptive study suggests that it is a molecule worthy of further study.

ANTI-VIMENTIN ANTIBODIES ARE ASSOCIATED WITH CHRONIC ALLOGRAFT NEPHROPATHY (CAN) IN RHESUS MONKEYS AND THE INCIDENCE IS DEPENDENT ON THE TYPE OF IMMUNOSUPPRESSION USED

P965 Aims: Chronic allograft nephropathy (CAN) is a common late complication of kidney transplantation. Antibodies have often been implicated in the development of this condition. Here we describe the presence of anti-vimentin antibodies in non-human primate recipients of kidney allografts as a possible predictor of CAN. Vimentin is expressed in normal rhesus monkey kidney in the vessel walls of peritubular capilaries and in the glomeruli. Enhanced expression in fibroblast is seen in early kidney biopsies (day 21 after transplantation). Methods: Rhesus monkeys that received a kidney allograft to study the immunosuppressive potency of several different immunosuppressive regimens were tested for the presence of anti-vimentin antibody by ELISA and for the presence of anti-donor antibody by staining donor spleen cells with recipient serum and FACS analysis. The appearance of antibodies were correlated with the graft pathology in biopsy and necropsy material (rejection grading according to Banff criteria). Results: Anti-vimentin antibodies were found in 27 of 33 animals, while only 15 of 32 animals made anti-donor antibodies. Conventional immunosuppression (T-cell depletion, cyclosporine, rapamycin) did not prevent anti-vimentin antibody formation. In contrast, costimulation blockade, in particular blocking CD40 plus CD86 delayed or prevented anti-vimentin antibody formation. There was a stronger association between the presence of anti-vimentin and the occurrence of CAN (P=0.026 in the costimulation blockade group) than between anti-donor antibodies and CAN (P=0.855 in the costimulation blockade group). Conclusions: S We hypothesize that after transplantation aberrant vimentin expression and the release of vimentin by cells dying in the graft as a result of reperfusion injury or subclinical rejection episodes may lead to an anti-vimentin response. Whether these antibodies are directly responsible for the later occurrence of CAN is not yet clear. Anti-vimentin antibodies can be a useful predictor for CAN after kidney transplantation.

The role of the protocol biopsies in renal allograft recipients

Subclinical rejection and long-term cyclosporine nephrotoxicity are well-known risk factors of chronic allograft nephropathy. In a prospective study 32 low-risk patients were randomized to either a reduced CsA dose (5 mg/kg/d) and daclizumab (group A, n = 16) for 7 months posttransplant with subsequent CsA tapering/withdrawal, or to a normal CsA dose (10 mg/kg/day) without daclizumab (group B, n = 16). Both groups received MMF and prednisone. Protocol biopsies were obtained at engraftment and 3 and 12 months after Tx. The number of rejection episodes was the primary endpoint. The secondary endpoints were: renal function, histological parameters related to CsA, and serum levels of TGF-β and PDGF-BB. A low incidence of clinically suspected rejection episodes was observed (19% in group A and 12.4% in group B; P = NS). Although protocol biopsies showed 12 subclinical rejection episodes (six in group A, six in group B), serum creatinine levels were not different between the examined groups at 3 months. However, at 12 months, there was a statistically improved mean creatinine level in group A patients (1.2 mg/dL ± 0.5 in group A vs 1.54 mg/dL in group B; P < .05). Chronic histopathologic changes were significant for biopsies at 3 and 12 months in both groups compared to the baseline findings for protocol biopsies (with no differences between groups, or between 3 and 12 months in both groups). Serum TGF-β and PDGF-BB did not differ between the groups. Protocol biopsies may be useful to monitor safety and efficiency of new immunosuppressive protocols. Immunosuppressive regimens with low CsA doses followed by the drug's complete withdrawal seem to be efficient and safe in low-risk kidney allograft recipients.

Plasma C3a and C4a levels in liver transplant recipients: a longitudinal study.

Liver transplant patients were enrolled in a study designed to investigate correlations between plasma complement C3a or C4a levels and various postoperative complications. Longitudinal EDTA-plasma levels of C3a and C4a were measured by quantitative radioimmunoassay. Acute rejection gave a characteristic and marked increase in blood C3a, C4a and gamma-glutamyl transferase (gammaGT) levels, which rapidly resolved after high dose steroid treatment. Cytomegalovirus (CMV) infections in two of three patients gave an initial small increase only in C3a levels (i.e., alternative pathway activation) followed approximately 6 weeks later by a marked increase in C4a levels (i.e., classical or lectin pathway activation). In a third patient diagnosed for CMV infection, the complement activation profile was complicated by a coincident minor rejection episode. However, a late stage elevation in C4a was also noted. Two patients experiencing biopsy proven recurrent hepatitis C infections following transplantation exhibited increases in both gammaGT and C4a levels, without a significant increase in the level of C3a. Several hepatitis C and one hepatitis B patient had multiple late activation episodes involving marked elevation in both plasma C3a and C4a levels without detectable increases in the liver enzymes conventionally used to monitor organ function. We also showed that ex vivo activation of complement in EDTA plasma from all transplant patients was abnormally high. The classical or lectin pathway is believed to be responsible for this excessive ex vivo complement activation in the plasma of these patients. Therefore, subclinical rejection episodes and/or viral infections may be effectively detected or monitored by measuring C3a and C4a levels in plasma samples from liver transplant patients. Routine measurement of plasma complement products may provide an early non-invasive mode for detecting infections and also serve to monitor chronic or acute changes in the patient's immune system.

Plasma C3a and C4a levels in liver transplant recipients: A longitudinal study

Abstract Liver transplant patients were enrolled in a study designed to investigate correlations between plasma complement C3a or C4a levels and various postoperative complications. Longitudinal EDTA–plasma levels of C3a and C4a were measured by quantitative radioimmunoassay. Acute rejection gave a characteristic and marked increase in blood C3a, C4a and gamma-glutamyl transferase (γGT) levels, which rapidly resolved after high dose steroid treatment. Cytomegalovirus (CMV) infections in two of three patients gave an initial small increase only in C3a levels (i.e., alternative pathway activation) followed approximately 6 weeks later by a marked increase in C4a levels (i.e., classical or lectin pathway activation). In a third patient diagnosed for CMV infection, the complement activation profile was complicated by a coincident minor rejection episode. However, a late stage elevation in C4a was also noted. Two patients experiencing biopsy proven recurrent hepatitis C infections following transplantation exhibited increases in both γGT and C4a levels, without a significant increase in the level of C3a. Several hepatitis C and one hepatitis B patient had multiple late activation episodes involving marked elevation in both plasma C3a and C4a levels without detectable increases in the liver enzymes conventionally used to monitor organ function. We also showed that ex vivo activation of complement in EDTA plasma from all transplant patients was abnormally high. The classical or lectin pathway is believed to be responsible for this excessive ex vivo complement activation in the plasma of these patients. Therefore, subclinical rejection episodes and/or viral infections may be effectively detected or monitored by measuring C3a and C4a levels in plasma samples from liver transplant patients. Routine measurement of plasma complement products may provide an early non-invasive mode for detecting infections and also serve to monitor chronic or acute changes in the patient's immune system.

Histological findings in early routine biopsies of stable renal allograft recipients.

Seventy renal allograft biopsies were done in 31 patients, routinely at 1, 2, and 3 months posttransplant, and as clinically indicated, using an automated biopsy "gun." The histological diagnosis was made according to the Banff schema, which emphasizes tubulitis and vascular inflammation over mononuclear cell infiltration. Fifty-three biopsies satisfied histological inclusion criteria. Twenty-nine biopsies were obtained from stable patients, defined as those in whom serum creatinine had changed < 10% in 2 weeks, and in whom immunosuppression (cyclosporine, azathioprine, and prednisone) had not been increased in that interval. Of these biopsies, 30% (9/29) showed rejection, which could not have been predicted from pretransplant (HLA mismatch, panel-reactive antibody titer) or posttransplant (cyclosporine and serum interleukin 2 receptor levels) variables. The significance of these early subclinical rejection episodes is unknown, and their effects on long-term graft histology and function are being examined in a controlled study.

Further assessment of rosette inhibition test in clinical organ transplantation.

The rosette inhibition test was used in the clinical management of organ allografts to estimate the amount of immunosuppressive drugs necessary to prevent rejection. In patients surviving more than three months renal function appeared to be better than in a similar group of patients managed without the test. It is suggested that this was due to a reduction in the number of clinical or subclinical rejection episodes. On the other hand, the test indicates that in many cases the level of immunosuppression should be much higher, and if this advice is followed the patients become increasingly exposed to the risk of infection. In other words, those patients with good renal function remained well, whereas those who might otherwise have rejected their kidney and survived had in fact died of sepsis.