Allograft Fibrosis Research Articles

Usefulness of real-time sonoelastography for assessment of renal allograft fibrosis

Background: Currently, allograft renal biopsy is the only reliable tool available to detect fibrosis in the transplanted kidney. However, it is an invasive procedure and is associated with complications. Therefore, a noninvasive tool to detect renal allograft fibrosis is needed. Aims: The aim of the study was to evaluate the usefulness of real-time sonoelastography (RTS) in the diagnosis of renal allograft fibrosis. Subjects and Methods: We studied 15 renal allograft recipients who had chronic allograft nephropathy. RTS was performed by an experienced radiologist to semi-quantitatively determine cortical and medullary stain ratio. These parameters were compared with the degree of fibrosis as assessed by allograft renal biopsy. For comparison, patients were divided into two groups based on the degree of fibrosis: those with mild fibrosis (interstitial fibrosis and tubular atrophy [IFTA] 25%). A receiver operating characteristic (ROC) curve analysis was performed to evaluate the accuracy of cortical strain ratio to discriminate between patients with mild fibrosis versus patients with moderate-to-severe fibrosis. Results: The mean cortical strain ratio was significantly higher in those who had mild fibrosis as compared to those who had moderate-to-severe fibrosis (2.46 ± 0.55 vs. 1.78 ± 0.15, P = 0.01), while the medullary strain ratio was comparable between the two groups. The diagnostic accuracy of cortical strain ratio, as evaluated by area under the curve of ROC analysis, was 0.96. Conclusion: RTS can differentiate between mild fibrosis and moderate-to-severe fibrosis with high accuracy.

Peripheral Donor-specific Antibodies Are Associated With Histology and Cellular Subtypes in Protocol Liver Biopsies of Pediatric Recipients.

The cellular infiltrate in protocol liver biopsies (PB) following pediatric liver transplantation remains mostly uncharacterized, yet there is increasing concern about the role of inflammation and fibrosis in long-term liver allografts. We aimed to define cell types in PB and to analyze their relationship with donor-specific antibodies (DSA) and histological phenotype. PB were performed at least 1 year after transplantation. We identified 4 phenotypes: normal, fibrosis, inflammation, inflammation with fibrosis. Cell types were counted after immunostaining for CD3, CD4, CD8, CD68, CD20, MUM1, and FoxP3. Forty-four patients underwent 1 PB between 2000 and 2015. Eleven percent (5/44) of PB displayed normal histology, 13.6% (6/44) fibrosis, 34.1% (15/44) inflammation, and 40.9% (18/44) inflammation and fibrosis. The main cell types in the portal tracts and lobules were CD3+ and CD68+ cells. Frequency of de novo DSA was 63% (27/44). The presence of CD8+ cells in the lobules was associated with fibrosis. Inflammation and fibrosis in PB were associated with the presence of circulating de novo DSA, number of de novo DSA, and C1q binding activity when compared to other phenotypes. T cells (CD3+) and macrophages (CD68+) were the most prevalent cell-types in PB. In the presence of inflammation, portal tracts were enriched in CD3+, CD20+ but displayed fewer CD68+. This coincided with the presence and number of de novo DSA. How these cellular and humoral actors interact is unclear, but peripheral DSA may be a marker of immune cellular activity in the seemingly quiescent allograft.

Single Nucleotide Polymorphisms of Ubiquitin-Related Genes were Associated with Allograft Fibrosis of Renal Transplant Fibrosis.

BackgroundInterstitial fibrosis and tubular atrophy (IF/TA) have been recognized as crucial factors contributing to graft loss resulting from chronic renal allograft injuries. Recent studies have indicated a significant association between the progression of organ fibrosis and single nucleotide polymorphisms (SNPs) found on certain genes. Our research sought to understand these potential associations and detect the potential impact of SNPs on ubiquitin-related genes related to allograft fibrosis in kidney transplant recipients.Material/MethodsThere were 200 patients enrolled in this study, from which samples were extracted for total DNA. Targeted next-generation sequencing was used to detect SNPs on 9 genes (FBXL21, PIAS1/2, SUMO1/2/3/4, UBE2D1, and UBE2I). Minor allele frequency (MAF) and Hardy-Weinberg equilibrium (HWE) tests were used and followed by linkage disequilibrium analysis. General linear models (GLM) were used to identify significant confounding factors. Finally, multiple inheritance models and haplotype analyses were conducted to explore associations between SNPs and the degree of the severity of renal allograft fibrosis.ResultsIn total, 144 SNPs were identified in targeted sequencing. After filtering based on results from MAF and HWE tests, 15 tagger SNPs were selected for further analyses of associations. GLMs indicated that the administration of sirolimus significantly contributed to the degree of severity of allograft fibrosis (P=0.011). After adjusting for confounding factors and applying a Bonferroni correction, multiple inheritance model analyses indicated that the recessive model of rs644731 of the PIAS2 gene was significantly correlated with the occurrence of IF/TA (P=0.01). Furthermore, single-locus based analysis of rs644731 did not indicate that it had a positive influence on IF/TA in a degree-dependent manner. Finally, linkage disequilibrium analysis revealed 3 haplotypes all lacking significant correlation with respect to the IF/TA experimental cohort.ConclusionsWe are the first to reveal that mutations of rs644731 in the PIAS2 gene were significantly correlated with the progression of IF/TA in kidney transplant recipients.

Tissue inhibitor of metalloproteinase 1 and AST-to-Platelet Ratio Index as noninvasive biomarkers predict allograft fibrosis after pediatric liver transplantation.

Assessing liver fibrosis in patients after liver transplantation is still largely dependent on liver biopsy. Especially in children, noninvasive methods are of utmost importance. We evaluated tissue inhibitor of metalloproteinase 1 (TIMP1) and AST-to-Platelet Ratio Index (APRI) and their potential as serum biomarkers to predict liver allograft fibrosis (LAF) in a pediatric cohort. In this retrospective, observational study, we analyzed 91 protocol liver biopsy specimens from 73 children after pediatric liver transplantation (PLT) and compared histological stage of liver fibrosis using LAF Score (LAFSc) and Ishak Score (IshakSc) to TIMP1-serum concentration and APRI using ROC analysis. In our cohort, TIMP1 and APRI reliably predict LAF. Depending on the histological scoring system, cutoff values for TIMP1 were 328ng/mL (IshakSc≥IV) and 351ng/mL (LAFSc≥5) with AUC of 0.86 and 0.98. The cutoff for APRI was 0.8 with AUC of 0.87 (IshakSc≥IV) and 0.94 (LAFSc≥5). Using LAFSc, TIMP1 and APRI showed excellent diagnostic accuracy to detect severe LAF (LAFSc≥5) with PPV of≥90% and NPV of 100%. TIMP1 and APRI are accurate biomarkers to predict severe LAF in children. The use of TIMP1 and APRI will not replace but complement liver biopsies after PLT to further improve our understanding of each individual patient.

A B cell-dependent pathway drives chronic lung allograft rejection after ischemia-reperfusion injury in mice.

Chronic lung allograft dysfunction (CLAD) limits long-term survival after lung transplant (LT). Ischemia-reperfusion injury (IRI) promotes chronic rejection (CR) and CLAD, but the underlying mechanisms are not well understood. To examine mechanisms linking IRI to CR, a mouse orthotopic LT model using a minor alloantigen strain mismatch (C57BL/10 [B10, H-2b ] → C57BL/6 [B6, H-2b ]) and isograft controls (B6→B6) was used with antecedent minimal or prolonged graft storage. The latter resulted in IRI with subsequent airway and parenchymal fibrosis in prolonged storage allografts but not isografts. This pattern of CR after IRI was associated with the formation of B cell-rich tertiary lymphoid organs within the grafts and circulating autoantibodies. These processes were attenuated by B cell depletion, despite preservation of allograft T cell content. Our observations suggest that IRI may promote B cell recruitment that drives CR after LT. These observations have implications for the mechanisms leading to CLAD after LT.

Combination of Functional Magnetic Resonance Imaging and Histopathologic Analysis to Evaluate Interstitial Fibrosis in Kidney Allografts.

Recent developments indicated that functional magnetic resonance imaging (MRI) could potentially provide noninvasive assessment of kidney interstitial fibrosis in patients with kidney diseases, but direct evidence from histopathology is scarce. We aimed to explore the diagnostic utilities of functional MRI for the evaluation of kidney allograft interstitial fibrosis. We prospectively examined 103 kidney transplant recipients who underwent for-cause biopsies and 20 biopsy-proven normal subjects with functional MRI. Histomorphometric analyses of interstitial fibrosis and peritubular capillary densities were performed on digitally scanned Masson's trichrome- and CD34-stained slides, respectively. The performances of functional MRI to discriminate interstitial fibrosis were assessed by calculating the area under the curve using receiver-operating characteristic curve. Main pathologic findings in this single-center cohort were representative of common diagnostic entities in the kidney allografts, with rejection (32%) and glomerulonephritides (31%) accounting for the majority of diagnoses. Apparent diffusion coefficient from diffusion-weighted imaging correlated with interstitial fibrosis (ρ=-0.77; P<0.001). Additionally, decreased arterial spin labelings were accompanied by peritubular capillary density reductions (r=0.77; P<0.001). Blood oxygen level-dependent (BOLD) imaging demonstrated cortical hypoxia with increasing interstitial fibrosis (ρ=0.61; P<0.001). The area under the curve for the discrimination of ≤25% versus >25% interstitial fibrosis and ≤50% versus >50% interstitial fibrosis were 0.87 (95% confidence interval [95% CI], 0.79 to 0.93) and 0.88 (95% CI, 0.80 to 0.93) by apparent diffusion coefficient, 0.92 (95% CI, 0.85 to 0.97) and 0.94 (95% CI, 0.87 to 0.98) by arterial spin labeling, 0.81 (95% CI, 0.72 to 0.88) and 0.86 (95% CI, 0.78 to 0.92) by perfusion fraction, 0.79 (95% CI, 0.69 to 0.87) and 0.85 (95% CI, 0.76 to 0.92) by BOLD imaging, respectively. Functional MRI measurements were strongly correlated with kidney allograft interstitial fibrosis. The performances of functional MRI for discriminating ≤50% versus >50% interstitial fibrosis were good to excellent.

Non-Invasive Assessment of Graft Fibrosis After Living Donor Liver Transplantation: Is There Still a Role for Liver Biopsy?

Non-invasive methods have evolved as a surrogate for liver biopsy such as indirect markers (aspartate transaminase to platelet ratio index, fibro-α score), transient elastography (TE), and magnetic resonance elastography (MRE).The aim of this study is to prospectively compare the value of MRE, TE, and indirect markers in detecting and staging allograft fibrosis compared to liver biopsies in patients who have undergone living donor liver transplantation for complications related to hepatitis C virus.A total of 31 living donor liver transplantation recipients with hepatitis C virus recurrence underwent a liver biopsy, TE, and MRE within 3 months of a liver biopsy. Fibrosis was assessed according to the biopsy and staged according to Metavir criteria.There was a significant correlation between both MRE and fibro-α scores, as well as histologic classification by liver biopsy (P = .02, .002). The diagnostic accuracy of MRE and fibro-α scores in diagnosing significant fibrosis (F ≥ 3) was measured as the area under the curve (.708 and .833, respectively). Both methods showed good diagnostic performance. TE and aspartate transaminase to platelet ratio index were insignificantly correlated with the degree of fibrosis in liver biopsy (P value of .134, .535). At a cutoff value of 5.5 kPa, MRE predicted graft fibrosis (Metavir stage ≥ 3) with 71.43% sensitivity, 75% specificity, 45.5% positive predictive value, and 90% negative predictive value; at a cutoff value > 1.47, fibro-α scores predicted significant graft fibrosis (Metavir stage ≥ 3) with 85.7% sensitivity and 70.83% specificity, with a positive predictive value of 46.2% and a negative predictive value of 94.4%. These data suggest that non-invasive methods could be considered a reliable tool in assessing significant graft fibrosis post-living donor liver transplantation.

Cytomegalovirus prevention strategies and the risk of BK polyomavirus viremia and nephropathy.

Polyomavirus BK (BKV) is the cause of polyomavirus-associated nephropathy resulting in premature graft loss. There are limited data regarding the role of cytomegalovirus (CMV) infection and its prevention in developing BKV viremia and PVAN. In a prospective study, we analyzed 207 consecutive renal transplant recipients previously enrolled in 2 randomized trials evaluating different CMV prevention regimens with routine screening for BKV and CMV. Of these, 59 received valganciclovir and 100 valacyclovir prophylaxis; 48 patients were managed by preemptive therapy. At 3years, the incidence of BKV viremia and PVAN was 28% and 5%, respectively. CMV DNAemia developed in 55% and CMV disease in 6%. Both BKV viremia (42% vs 23% vs 21%, P=.006) and PVAN (12% vs 2% vs 2%, P=.011) were increased in patients treated with valganciclovir prophylaxis compared to valacyclovir and preemptive therapy. Using multivariate Cox proportional hazard regression, valganciclovir prophylaxis was independent predictor of BKV viremia (hazard ratio [HR]=2.38, P=.002) and PVAN (HR=4.73, P=.026). In contrast, the risk of subsequent BKV viremia was lower in patients with antecedent CMV DNAemia (HR=0.50, P=.018). These data suggest valganciclovir prophylaxis may be associated with increased risk of BKV viremia and PVAN. CMV DNAemia did not represent a risk for BKV.

Late allograft fibrosis in pediatric liver transplant recipients: Assessed by histology and transient elastography.

Late allograft fibrosis in LT recipients can cause graft dysfunction and may result in re-transplantation. TE is a non-invasive tool for the assessment of liver fibrosis. We aimed to evaluate the prevalence of allograft fibrosis in pediatric LT recipients, identify factors associated with allograft fibrosis, and determine the diagnostic value of TE, compared to histology. All children who underwent LT for ≥3years were included. TE was performed for LSM in all patients. LSM of ≥7.5kPa was considered as abnormal and suggestive of allograft fibrosis. Percutaneous liver biopsy was performed when patients had abnormal LSM and/or abnormal LFTs. Histological fibrosis was diagnosed when METAVIR score ≥F1 or LAF scores ≥1. TE was performed in 43 patients and 14 (32.5%) had abnormal LSM suggestive of allograft fibrosis. Histological fibrosis was identified in 10 of the 15 patients (66.7%) who underwent percutaneous liver biopsy and associated findings included chronic active HBV infection (n=3), and late acute rejection (n=3). Multivariate analysis showed that graft age was significantly associated with allograft fibrosis (OR=1.22, 95% CI: 1.05-1.41, P=0.01). In conclusion,late allograft fibrosis is common in children undergoing LT for ≥3years and associated with graft age. HBV infection and late acute rejection are common associated findings. Abnormal TE and/or LFTs may guide physicians to consider liver biopsy for the detection of late allograft fibrosis in LT children.

IL-3 Triggers Chronic Rejection of Cardiac Allografts by Activation of Infiltrating Basophils.

Chronic rejection is a major problem in transplantation medicine, largely resistant to therapy, and poorly understood. We have shown previously that basophil-derived IL-4 contributes to fibrosis and vasculopathy in a model of heart transplantation with depletion of CD4+ T cells. However, it is unknown how basophils are activated in the allografts and whether they play a role when cyclosporin A (CsA) immunosuppression is applied. BALB/c donor hearts were heterotopically transplanted into fully MHC-mismatched C57BL/6 recipients and acute rejection was prevented by depletion of CD4+ T cells or treatment with CsA. We found that IL-3 is significantly upregulated in chronically rejecting allografts and is the major activator of basophils in allografts. Using IL-3-deficient mice and depletion of basophils, we show that IL-3 contributes to allograft fibrosis and organ failure in a basophil-dependent manner. Also, in the model of chronic rejection involving CsA, IL-3 and basophils substantially contribute to organ remodeling, despite the almost complete suppression of IL-4 by CsA. In this study, basophil-derived IL-6 that is resistant to suppression by CsA, was largely responsible for allograft fibrosis and limited transplant survival. Our data show that IL-3 induces allograft fibrosis and chronic rejection of heart transplants, and exerts its profibrotic effects by activation of infiltrating basophils. Blockade of IL-3 or basophil-derived cytokines may provide new strategies to prevent or delay the development of chronic allograft rejection.

The prior exposure of CD4+ T cells to alloantigen blunts their secretion of the reparative growth factor amphiregulin

Abstract Objective Chronic rejection (CR) manifests after transplantation as function-limiting allograft fibrosis and vasculopathy. Insights into the mechanisms leading to CR are needed to develop effective therapies. The aggressive development of fibrosis during CR is similar to that observed in unproductive injury repair. Thus, we investigated how alloantigen (AlloAg) shapes novel mechanisms of immune-mediated tissue repair. Amphiregulin (Areg) is a growth factor secreted by innate and adaptive immune cells in response to IL-33 released during tissue injury. As IL-33 and Areg are implicated in muscle, epithelium, and nerve repair, we defined how AlloAg recognition by CD4+ T cells modulates IL-33-induced Areg secretion. Method C57BL/6 mice transgenic for a TCR recognizing a BALB/c-derived alloAg (Eα52–68) presented on I-Ab were administered IL-33 or Eα52–68 alone, or combined, 10 days before CD4+ T cell isolation. Areg secretion by isolated CD4+ during 4 days of culture with IL-33 or Eα52–68 was measured by ELISA. The signaling mediating Areg secretion was defined using inhibitors. Results CD4+ T cell exposure to IL-33 prior to alloAg secreted Areg upon de novo AlloAg exposure or secondary IL-33 stimulation. Exposure to AlloAg before IL-33, however, limited the capacity of alloreactive T cells to secrete Areg in response to either IL-33 or alloAg. Using the P38 inhibitor SB203580 and NF-κB inhibitors MG132 and TCPA-1 we established that both NF-κB and p38 are critical CD4+ T secretion of Areg. Conclusion Our studies suggest that recognition of AlloAg disrupts a reparative response mediated by CD4+ T cells. Limiting the reparative capacity of non-self T cells may aid pathogen clearance, but support development of CR in after transplant.

SDF‑1/CXCR4 induces epithelial‑mesenchymal transition through activation of the Wnt/β‑catenin signaling pathway in rat chronic allograft nephropathy.

Epithelial-mesenchymal transition (EMT) has been demonstrated to serve a crucial role in the progression of interstitial fibrosis, which is one of the principal pathological features of chronic allograft nephropathy (CAN). However, to the best of our knowledge, the mechanisms of EMT in CAN have not been investigated. In the present study, the effect of stromal cell-derived factor 1 (SDF-1) and the Wnt signaling pathway on the progression of EMT following kidney transplantation was investigated. The CAN model was established using Fisher 344 and Lewis rats, treated with low-dose cyclosporine with or without AMD3100. CAN was confirmed by the pathological alterations and chronic allograft damage index scoring, and EMT was confirmed by western blotting and reverse transcription-quantitative polymerase chain reaction. In the AMD3100 group, there were lower expression levels of α-SMA and higher expression levels of E-cadherin, which indicated that CAN and EMT were ameliorated by AMD3100. The kidney tissue was analyzed using an mRNA + long noncoding (lnc)RNA microarray. A total of 506 mRNAs and 404 lncRNAs were demonstrated to be significantly differentially expressed between the two groups, which revealed the involvement of SDF-1/CXC chemokine receptor 4 (CXCR4) and the Wnt pathway. SDF-1 was demonstrated to induce EMT in vitro through the upregulation of α-SMA, downregulation of E-cadherin and the wound healing assay, and in the rat renal tubular epithelial cells via the nuclear accumulation of β-catenin, which were all inhibited by either AMD3100 or DKK-1. CXXC finger protein 5 (CXXC5), a negative regulator of the Wnt pathway, was downregulated following treatment with SDF-1, which was inhibited by AMD3100 but not by DKK-1. Thus, CXXC5 may be a regulator downstream of SDF-1/CXCR4 in EMT. In conclusion, SDF-1/CXCR4 induces EMT of renal tubular epithelial cells with the involvement of the Wnt pathway, which may be a novel mechanism and therapeutic target in kidney allograft fibrosis of rats.

Fenofibrate Improved Interstitial Fibrosis of Renal Allograft through Inhibited Epithelial-Mesenchymal Transition Induced by Oxidative Stress

The best treatment for end-stage renal disease is renal transplantation. However, it is often difficult to maintain a renal allograft healthy for a long time following transplantation. Interstitial fibrosis and tubular atrophy (IF/TA) are significant histopathologic characteristics of a compromised renal allograft. There is no effective therapy to improve renal allograft function once IF/TA sets in. Although there are many underlying factors that can induce IF/TA, the pathogenesis of IF/TA has not been fully elucidated. It has been found that epithelial-mesenchymal transition (EMT) significantly contributes to the development of IF/TA. Oxidative stress is one of the main causes that induce EMT in renal allografts. In this study, we have used H2O2 to induce oxidative stress in renal tubular epithelial cells (NRK-52e) of rats. We also pretreated NRK-52e cells with an antioxidant (N-acetyl L-cysteine (NAC)) 1 h prior to the treatment with H2O2. Furthermore, we used fenofibrate (a peroxisome proliferator-activated receptor α agonist) to treat NRK-52e cells and a renal transplant rat model. Our results reveal that oxidative stress induces EMT in NRK-52e cells, and pretreatment with NAC can suppress EMT in these cells. Moreover, fenofibrate suppresses fibrosis by ameliorating oxidative stress-induced EMT in a rat model. Thus, fenofibrate may effectively prevent the development of fibrosis in renal allograft and improve the outcome.

T1ρ mapping for assessment of renal allograft fibrosis.

There is an unmet need for noninvasive methods to diagnose and stage renal allograft fibrosis. To investigate the utility of T1ρ measured with MRI for the assessment of fibrosis in renal allografts. Institutional Review Board (IRB)-approved prospective. Fifteen patients with stable functional allograft (M/F 9/6, mean age 56 years) and 12 patients with allograft dysfunction and established fibrosis (M/F 6/6, mean age 51 years). T1ρ imaging at 1.5T using a custom-developed sequence. Average T1ρ in the cortex and medulla was quantified and T1ρ repeatability (expressed by the coefficient of variation [CV]) was measured in four patients. Differences in T1ρ values between the 2 groups were assessed using Mann-Whitney U-tests. Diagnostic performance of T1ρ for differentiation between functional and fibrotic allografts was evaluated using receiver operating characteristic (ROC) analysis. Spearman correlations of T1ρ with Masson's trichrome-stained fractions and serum estimated glomerular filtration rate (eGFR) were assessed. Higher T1ρ repeatability was found for cortex compared with medulla (mean CV T1ρ cortex 7.4%, medulla 13.3%). T1ρ values were significantly higher in the cortex of fibrotic vs. functional allografts (111.8 ± 17.2 msec vs. 99.0 ± 11.0 msec, P = 0.027), while there was no difference in medullary T1ρ values (122.6 ± 20.8 msec vs. 124.3 ± 20.8 msec, P = 0.789). Cortical T1ρ significantly correlated with Masson's trichrome-stained fractions (r = 0.515, P = 0.044) and eGFR (r = -0.546, P = 0.004), and demonstrated an area under the curve (AUC) of 0.77 for differentiating between functional and fibrotic allografts (sensitivity and specificity of 75.0% and 86.7%, using threshold of 106.9 msec). Our preliminary results suggest that T1ρ is a potential imaging biomarker of renal allograft fibrosis. These results should be verified in a larger study. 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1085-1091.

HLA, Non-HLA Antibodies, and Eplet Mismatches in Pediatric Liver Transplantation: Observations From a Small, Single-Center Cohort.

To identify the risk of developing acute rejection, allograft fibrosis, and antibody-mediated rejection, a retrospective review of pediatric patients who underwent liver transplant between July 31, 1998 and February 29, 2016 and had donor-specific antibodies measured at time of liver biopsy was undertaken. HLAMatchmaker Software (http://www.hlamatchmaker.net) was used to define epitope mismatches between donors and recipients and to predict de novo donor-specific antibody risk. Epitope mismatches were evaluated for their immunogenicity. In our group of 42 recipients, 20 (48%) had donor-specific antibodies. Having an antibody against HLA-DQB1*02 was associated with acute rejection (66.6% vs 36%; P = .024). We found that DQ epitope mismatch load was greater in recipients with class II donor-specific antibodies (9.7 vs 3.6; P = .001). HLA-DQ (7.4 vs 3.6; P = .04) and HLA-DR (8.8 vs 3.8; P = .04) epitope mismatch loads were higher in recipients with DQ + DR donor-specific antibodies. A high portal fibrosis score was associated with higher mismatch load at the DQ locus (P = .005) and DQ + DR loci (P = .03). Having > 5 or > 6 epitope mismatch loads at the DQ locus identified a threshold above which development of DQ donor-specific antibodies would occur (area under the curve = 0.878). Mismatches for eplet 4Q, 45GE, 52PQ, and 52PL, thought to be immunodominant epitopes, were observed for several recipients. Knowledge of epitope mismatches between recipients and donors may aid transplant physicians in devising immunosuppression strategies.

Urinary transglutaminase 2 as a potent biomarker to predict interstitial fibrosis and tubular atrophy of kidney allograft during early posttransplant period in deceased donor kidney transplantation.

PurposeTransglutaminase type 2 (TG2) is an extracellular matrix crosslinking enzyme with a pivotal role in kidney fibrosis. We tested whether quantification of urinary TG2 may represent a noninvasive method to estimate the severity of kidney allograft fibrosis.MethodsWe prospectively collected urine specimens from 18 deceased donor kidney transplant recipients at 1-day, 7-day, 1-month, 3-month, and 6-month posttransplant. In addition, kidney allograft tissue specimens at 0-day and 6-month posttransplant were sampled to analyze the correlation of urinary TG2 and kidney allograft fibrosis.ResultsThirteen recipients had increased interstitial fibrosis and tubular atrophy (IFTA) scores at the 6-month protocol biopsy (IFTA group). The mean level of urinary TG2 in the IFTA group was higher compared to that of 5 other recipients without IFTA (no IFTA group). Conversely, the mean level of urinary syndecan-4 in the IFTA group was lower than levels in patients without IFTA. In the IFTA group, double immunofluorescent staining revealed that TG2 intensity was significantly upregulated and colocalizations of TG2/heparin sulfate proteoglycan and nuclear syndecan-4 were prominent, usually around tubular structures.ConclusionUrinary TG2 in early posttransplant periods is a potent biomarker for kidney allograft inflammation or fibrosis.

Silent allograft fibrosis in 10-year post-transplantation histology of pediatric liver transplantation: Is it really silent?

Silent allograft fibrosis in 10-year post-transplantation histology of pediatric liver transplantation: Is it really silent?

Alteration of urinary neutrophil gelatinase-associated lipocalin as a predictor of tacrolimus-induced chronic renal allograft fibrosis in tacrolimus dose adjustments following kidney transplantation.

Despite tacrolimus (TAC) drug-level monitoring, TAC-induced chronic renal allograft fibrosis remains an important problem. This study investigated the potential of urinary neutrophil gelatinase–associated lipocalin (uNGAL) as a chronic renal allograft fibrosis biomarker in a two-phase study (proof of concept and cohort). In the proof of concept stage of the study, increased TAC-doses at 3 days after dose adjustment compared with the baseline were associated with elevated uNGAL (+ΔuNGAL) and urinary interleukin 18 (IL-18), but normal serum creatinine (SCr), despite the therapeutic trough levels of TAC. In the cohort study, the patients with elevated uNGAL post-recruitment in comparison with the baseline (+ΔuNGAL) was associated with the more severe renal allograft fibrosis from renal pathology of the protocol biopsy at 12 months post kidney transplantation (post-KT). A cut-off value of uNGAL ≥ 125.2 ng/mL during a 3, 6, 9 and 12 months post-KT was associated with a higher fibrosis score, with an area under the receiver operating characteristics curve of 0.80 (95% confidence interval [CI] 0.72 to 0.88, p < 0.0001) and a hazard ratio (HR) of 2.54 (95% CI 1.45 to 9.33; p < 0.001). We conclude that uNGAL is a sensitive biomarker of TAC induced subtle renal injury and TAC-induced chronic renal allograft fibrosis. We propose that uNGAL measurements, in addition to trough levels of TAC, should be used to predict TAC-induced chronic renal allograft fibrosis in the recipients of KT.

Spectrum of chronic lung allograft pathology in a mouse minor-mismatched orthotopic lung transplant model.

Chronic lung allograft dysfunction (CLAD) is a fatal condition that limits survival after lung transplantation (LTx). The pathological hallmark of CLAD is obliterative bronchiolitis (OB). A subset of patients present with a more aggressive CLAD phenotype, called restrictive allograft syndrome (RAS), characterized by lung parenchymal fibrosis (PF). The mouse orthotopic single LTx model has proven relevant to the mechanistic study of allograft injury. The minor-alloantigen-mismatched strain combination using C57BL/10(B10) donors and C57BL/6(B6) recipients reportedly leads to OB. Recognizing that OB severity is a spectrum that may coexist with other pathologies, including PF, we aimed to characterize and quantify pathologic features of CLAD in this model. Left LTx was performed in the following combinations: B10→B6, B6→B10, B6→B6. Four weeks posttransplant, blinded pathologic semi-quantitative assessment showed that OB was present in 66% of B10→B6 and 30% of B6→B10 grafts. Most mice with OB also had PF with a pattern of pleuroparenchymal fibroelastosis, reminiscent of human RAS-related pathology. Grading of pathologic changes demonstrated variable severity of airway fibrosis, PF, acute rejection, vascular fibrosis, and epithelial changes, similar to those seen in human CLAD. These assessments can make the murine LTx model a more useful tool for further mechanistic studies of CLAD pathogenesis.

Less renal allograft fibrosis with valganciclovir prophylaxis for cytomegalovirus compared to high-dose valacyclovir: a parallel group, open-label, randomized controlled trial

BackgroundCytomegalovirus (CMV) prophylaxis may prevent CMV indirect effects in renal transplant recipients. This study aimed to compare the efficacy of valganciclovir and valacyclovir prophylaxis for CMV after renal transplantation with the focus on chronic histologic damage within the graft.MethodsFrom November 2007 through April 2012, adult renal transplant recipients were randomized, in an open-label, single-center study, at a 1:1 ratio to 3-month prophylaxis with valganciclovir (n = 60) or valacyclovir (n = 59). The primary endpoint was moderate-to-severe interstitial fibrosis and tubular atrophy assessed by protocol biopsy at 3 years evaluated by a single pathologist blinded to the study group. The analysis was conducted in an intention-to-treat population.ResultsAmong the 101 patients who had a protocol biopsy specimen available, the risk of moderate-to-severe interstitial fibrosis and tubular atrophy was significantly lower in those treated with valganciclovir (22% versus 34%; adjusted odds ratio, 0.31; 95% confidence interval, 0.11–0.90; P = 0.032 by multivariate logistic regression). The incidence of CMV disease (9% versus 2%; P = 0.115) and CMV DNAemia (36% versus 42%; P = 0.361) were not different at 3 years.ConclusionsValganciclovir prophylaxis, as compared with valacyclovir, was associated with a reduced risk of moderate-to-severe interstitial fibrosis and tubular atrophy in patients after renal transplantation.Trial registrationAustralian New Zealand Clinical Trials Registry (ACTRN12610000016033). Registered on September 26, 2007