Long-Term Outcomes among Kidney Transplant Recipients and after Graft Failure: A Single-Center Cohort Study in Brazil.

BACKGROUND: The results of kidney transplantation are impacted by the categories of events responsible for patient death and graft failure. The objective of this study was to evaluate the causes of death and graft failure and outcomes after graft failure among kidney transplant recipients. METHODOLOGY: A retrospective cohort study was conducted with 944 patients who underwent kidney transplantation. Outcomes were categorized in a managed and hierarchical manner. RESULTS: The crude mortality rate was 10.8% (n=102): in 35.3% cause of death was infection, in 30.4% cardiovascular disease, and in 15.7% neoplasia and in 6.8%, it was not possible to determine the cause of death. The rate of graft loss was 10.6%. The main causes of graft failure were chronic rejection (40%), acute rejection (18.3%), thrombosis (17.3%), and recurrence of primary disease (16.5%). Failures due to an acute rejection occurred earlier than those due to chronic rejection and recurrence (p<0.0001). As late causes of graft loss, death with the functioning kidney occurred earlier than recurrence and chronic rejection (p=0.008). The outcomes after graft failure were retransplantation in 26.1% and death in 21.4%, at a mean of 25.5 and 21.4 months, respectively. CONCLUSION: It was possible to identify more than 90% of the events responsible for the deaths of transplanted patients, predominantly infectious and cardiovascular diseases. Among the causes of graft failure, chronic and acute rejections and recurrence were the main causes of graft failure which were followed more frequently by retransplantation than by death on dialysis.

Intragraft transcriptional profiling of renal transplant patients with tubular dysfunction reveals mechanisms underlying graft injury and recovery.

BACKGROUND: Proximal tubular dysfunction (PTD) is associated with a decreased long-term graft survival in renal transplant patients and can be detected by the elevation of urinary tubular proteins. This study investigated transcriptional changes in biopsies from renal transplant patients with PTD to disclose molecular mechanisms underlying graft injury and functional recovery. METHODS: Thirty-three renal transplant patients with high urinary levels of retinol-binding protein, a biomarker of PTD, were enrolled in the study. The initial immunosuppressive scheme included azathioprine, cyclosporine, and steroids. After randomization, 18 patients (group 2) had their treatment modified by reducing cyclosporine dosage and substituting azathioprine for mycophenolate mofetil, while the other 15 patients (group 1) remained under the initial scheme. Patients were biopsied at enrollment and after 12 months of follow-up, and paired comparisons were performed between their intragraft gene expression profiles. The differential transcriptome profiles were analyzed by constructing gene co-expression networks and identifying enriched functions and central nodes in each network. RESULTS: Only the alternative immunosuppressive scheme used in group 2 ameliorated renal function and tubular proteinuria after 12 months of follow-up. Intragraft molecular changes observed in group 2 were linked to autophagy, extracellular matrix, and adaptive immunity. Conversely, gene expression changes in group 1 were related to fibrosis, endocytosis, ubiquitination, and endoplasmic reticulum stress. CONCLUSION: These results suggest that molecular networks associated with the control of endocytosis, autophagy, protein overload, fibrosis, and adaptive immunity may be involved in improvement of graft function.

Administration of α-Galactosylceramide Improves Adenine-Induced Renal Injury.

Natural killer T (NKT) cells are a subset of lymphocytes that reacts to glycolipids presented by CD1d. Invariant NKT cells (iNKT) correspond to >90% of the total population of NKTs and reacts to α-galactosylceramide (αGalCer). αGalCer promotes a complex mixture of Th1 and Th2 cytokines, as interferon (IFN)-γ and interleukin (IL)-4. NKT cells and IFN-γ are known to participate in some models of renal diseases, but further studies are still necessary to elucidate their mechanisms. The aim of our study was to analyze the participation of iNKT cells in an experimental model of tubule-interstitial nephritis. We used 8-wk-old C57BL/6j, Jα18KO and IFN-γKO mice. They were fed a 0.25% adenine diet for 10 d. Both adenine-fed wild-type (WT) and Jα18KO mice exhibited renal dysfunction, but adenine-fed Jα18KO mice presented higher expression of kidney injury molecule-1 (KIM-1), tumor necrosis factor (TNF)-α and type I collagen. To analyze the role of activated iNKT cells in our model, we administered αGalCer in WT mice during adenine ingestion. After αGalCer injection, we observed a significant reduction in serum creatinine, proinflammatory cytokines and renal fibrosis. However, this improvement in renal function was not observed in IFN-γKO mice after αGalCer treatment and adenine feeding, illustrating that this cytokine plays a role in our model. Our findings may suggest that IFN-γ production is one of the factors contributing to improved renal function after αGalCer administration.

Urinary CD20 mRNA as a surrogate of CD20-positive cells infiltration during allograft dysfunction in renal transplant patients.

B lymphocyte infiltration in renal acute allograft rejection has been associated with steroid resistance and poor outcomes. We aimed to measure CD20 mRNA in urine of renal transplant patients with graft dysfunction and correlate with the histological diagnosis and immunohistochemical (IH) staining for CD20. A total of 48 urine samples were analyzed (21 with acute rejection, 10 with chronic allograft nephropathy, 11 with unspecific tubular lesions, 3 with acute pyelonephritis and 3 with polyomavirus nephropathy). Higher urinary CD20 levels associated with a positive IH staining for CD20 (>50 positive cells/HPF) in renal tissue (p=0.04), with a sensitivity of 83.3% and a specificity of 51.6%. Within the acute rejection group, a positive staining for CD20 was not associated with graft loss, steroid resistance or lack of return to basal creatinine after treatment, but was associated with higher serum creatinine at 3 and 6 months, 1 and 2 years after the acute episode (p<0.05). In conclusion, we showed that urinary levels of CD20 detected by RT-PCR had a high sensitivity for CD20+ staining in the corresponding renal tissue, but with a low specificity. Patients with clusters of CD20+ cells >50/HPF had higher serum creatinine after 2 years of follow up.

Toll-like receptors-related genes in kidney transplant patients with chronic allograft nephropathy and acute rejection.

INTRODUCTION: Toll-like receptors (TLR) comprehend an emerging family of receptors that recognize pathogen-associated molecular patterns and promote the activation of leukocytes. Surgical trauma and ischemia-reperfusion injury are likely to provide exposure to endogenous ligands for TLR in virtually all kidney transplant recipients. METHODS: Macroarray (GEArray OHS-018.2 Series-Superarray) analyses of 128 genes involved in TLR signaling pathway were performed in nephrectomy samples of patients with chronic allograft nephropathy (CAN) and acute rejection (AR, vascular and non vascular). The analysis of each membrane was performed by GEArray Expression Analysis Suite 2.0. RESULTS: Macroarray profile identified a gene expression signature that could discriminate CAN and AR. Three genes were significantly expressed between CAN and vascular AR: Pellino 2; IL 8 and UBE2V1. In relation to vascular and non-vascular AR, there were only two genes with statistical significance: IL-6 and IRAK-3. CONCLUSION: Vascular and non-vascular AR and CAN showed different expression of a few genes in TLR pathway. The analysis of nephrectomy showed that activation of TLR pathway is present in AR and CAN.

Detection of the Tim-3 ligand, galectin-9, inside the allograft during a rejection episode.

INTRODUCTION: Tim-3 is a Th1 lymphocytes membrane protein with inhibitory function. Its ligand, galectin-9, was recently identified and it is expressed in some lymphocyte subpopulation. In addition, endothelial cells and fibroblasts can also express galectin-9 according to the local cytokine milieu. Both molecules can act as important regulatory tools in the immune system. AIM: Evaluate the expression of these immunoregulatory molecules inside kidney allografts during acute rejection episodes. METHODS: By using a quantitative polymerase chain reaction assay, we measured the levels of messenger RNA (mRNA) for galectin-9 and Tim-3 in 21 samples obtained at allograft nephrectomy. Five samples received the histological diagnosis of acute non-vascular rejection (ANVR), twelve of acute vascular rejection (AVR), and five of loss of non-immune cause (LNIC; as control). As cytolytic response markers we measured mRNA levels of granzyme B, interferon-gamma and perforin. The statistic analysis was performed using one way analysis of variance (ANOVA) and Pearson correlation. RESULTS: The mean levels of Tim-3 mRNA expression were 13.99+/-6.99 for LNIC, 48.13+/-54.47 for RACNV and 238.63+/-333.14 for RAV (p=0.004). For galectin-9, the mean values were 0.57+/-0.49 for LNIC, 0.66+/-0.36 for RACNV and 2.34+/-1.62 for RAV (p=0.006). Furthermore, there was a positive correlation between both molecules (r=0.526, p=0.016). Also, granzyme B, perforin and interferon-gamma mRNA expression were different among the three groups. CONCLUSION: Messenger RNA level expressions of all the studied molecules were higher inside allografts with more severe rejection. Moreover, there was a positive correlation between galectin-9 and Tim-3 mRNA levels. The simultaneous expression of galectin-9 and Tim-3 may indicate an immunoregulatory function, during the ongoing cytotoxic response.

Vasculite necrotizante cutânea em paciente com artrite de Takayasu / Takayasu’s arteritis associated with cutaneous manifestations

O fato de a arterite de Takayasu ser um protótipo de doença de grandes vasos pode fazer com que as manifestações cutâneas, atribuídas ao acometimento de pequenos vasos, passem despercebidas. Descrevemos um caso de arterite de Takayasu associada a manifestações cutâneas decorrentes de vasculite necrotizante. Neste caso, correlacionamos os achados clínicos e laboratoriais com os da biópsia cutânea, estabelecendo o diagnóstico. A paciente respondeu prontamente ao regime terapêutico de prednisona e metotrexate.