High expression of TIM-3 and KIM-1 in blood and urine of renal allograft rejection patients

Elevated Serum KIM-1 in Sepsis Correlates with Kidney Dysfunction and the Severity of Multi-Organ Critical Illness

The kidney injury molecule (KIM)-1 is shed from proximal tubular cells in acute kidney injury (AKI), relaying tubular epithelial proliferation. Additionally, KIM-1 portends complex immunoregulation and is elevated after exposure to lipopolysaccharides. It thus may represent a biomarker in critical illness, sepsis, and sepsis-associated AKI (SA-AKI). To characterise and compare KIM-1 in these settings, we analysed KIM-1 serum concentrations in 192 critically ill patients admitted to the intensive care unit. Irrespective of kidney dysfunction, KIM-1 serum levels were significantly higher in patients with sepsis compared with other critical illnesses (191.6 vs. 132.2 pg/mL, p = 0.019) and were highest in patients with urogenital sepsis, followed by liver failure. Furthermore, KIM-1 levels were significantly elevated in critically ill patients who developed AKI within 48 h (273.3 vs. 125.8 pg/mL, p = 0.026) or later received renal replacement therapy (RRT) (299.7 vs. 146.3 pg/mL, p < 0.001). KIM-1 correlated with markers of renal function, inflammatory parameters, hematopoietic function, and cholangiocellular injury. Among subcomponents of the SOFA score, KIM-1 was elevated in patients with hyperbilirubinaemia (>2 mg/dL, p < 0.001) and thrombocytopenia (<150/nL, p = 0.018). In univariate and multivariate regression analyses, KIM-1 predicted sepsis, the need for RRT, and multi-organ dysfunction (MOD, SOFA > 12 and APACHE II ≥ 20) on the day of admission, adjusting for relevant comorbidities, bilirubin, and platelet count. Additionally, KIM-1 in multivariate regression was able to predict sepsis in patients without prior (CKD) or present (AKI) kidney injury. Our study suggests that next to its established role as a biomarker in kidney dysfunction, KIM-1 is associated with sepsis, biliary injury, and critical illness severity. It thus may offer aid for risk stratification in these patients.

Non-invasive molecular biomarkers for monitoring solid organ transplantation: A comprehensive overview

Solid organ transplantation is a life-saving intervention for individuals with end-stage organ failure. Despite the effectiveness of immunosuppressive therapy, the risk of graft rejection persists in all viable transplants between individuals. The risk of rejection may vary depending on the degree of compatibility between the donor and recipient for both human leucocyte antigen (HLA) and non-HLA gene-encoded products. Monitoring the status of the allograft is a critical aspect of post-transplant management, with invasive biopsies being the standard of care for detecting rejection. Non-invasive biomarkers are increasingly being recognized as valuable tools for aiding in the detection of graft rejection, monitoring graft status and evaluating the efficacy of immunosuppressive therapy. Here, we focus on the importance of molecular biomarkers in solid organ transplantation and their potential role in clinical practice. Conventional molecular biomarkers used in transplantation include HLA typing, detection of anti-HLA antibodies, killer cell immunoglobulin-like receptor genotypes, and anti-MHC class 1-related chain A antibodies, which are important for assessing the compatibility of the donor and recipient. Emerging molecular biomarkers include the detection of donor-derived cell-free DNA, microRNAs (regulation of gene expression), exosomes (small vesicles secreted by cells), and kidney solid organ response test, in the recipient's blood for early signs of rejection. This review highlights the strengths and limitations of these molecular biomarkers and their potential role in improving transplant outcomes.

Tim-3 deficiency aggravates cadmium nephrotoxicity via regulation of NF-κB signaling and mitochondrial damage

Kidney is the target organ of serious cadmium injury. Kidney damage caused by cadmium exposure is greatly influenced by the inflammatory response and mitochondrial damage. T cell immunoglobulin domain and mucin domain 3 (Tim-3) is an essential protein that functions as a negative immunological checkpoint to regulate inflammatory responses. Mice were given cadmium treatments at various dosages (0, 1.5, 3, 4.5 mg/kg) and times (0, 3, 5, 7 days) to assess the effects of cadmium on kidney damage. We found that the optimal way to induce kidney injury in mice was to inject 4.5 mg/kg of cadmium intraperitoneally for five days. It is interesting that giving mice 4.5 mg/kg of cadmium intravenously for seven days drastically lowered their survival rate. After cadmium exposure, Tim-3 knockout mice exhibited higher blood concentrations of urea nitrogen and creatinine compared to control mice. Tim-3 impacted the expression of oxidative stress-associated genes such as UDP glucuronosyltransferase family 1 member A9 (Ugt1a9), oxidative stress-induced growth inhibitor 2 (Osgin2), and S100 calcium binding protein A8 (S100a8), according to RNA-seq and real-time RT-PCR data. Tim-3 deficiency also resulted in activated nuclear factor-kappa B (NF-κB) signaling pathway. The NF-κB inhibitor 2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide (TPCA-1) significantly alleviated cell apoptosis, oxidative stress response, and renal tubule inflammation in Tim-3 knockout mice exposed to cadmium. Furthermore, cadmium caused obvious B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax) translocation from cytoplasm to mitochondria, which can be inhibited by TPCA-1. In conclusion, Tim-3 prevented mitochondrial damage and NF-κB signaling activation, hence providing protection against cadmium nephrotoxicity.

Biomarker-Development Proteomics in Kidney Transplantation: An Updated Review

Kidney transplantation (KT) is the optimal therapeutic strategy for patients with end-stage renal disease. The key to post-transplantation management is careful surveillance of allograft function. Kidney injury may occur from several different causes that require different patient management approaches. However, routine clinical monitoring has several limitations and detects alterations only at a later stage of graft damage. Accurate new noninvasive biomarker molecules are clearly needed for continuous monitoring after KT in the hope that early diagnosis of allograft dysfunction will lead to an improvement in the clinical outcome. The advent of “omics sciences”, and in particular of proteomic technologies, has revolutionized medical research. Proteomic technologies allow us to achieve the identification, quantification, and functional characterization of proteins/peptides in biological samples such as urine or blood through supervised or targeted analysis. Many studies have investigated proteomic techniques as potential molecular markers discriminating among or predicting allograft outcomes. Proteomic studies in KT have explored the whole transplant process: donor, organ procurement, preservation, and posttransplant surgery. The current article reviews the most recent findings on proteomic studies in the setting of renal transplantation in order to better understand the effective potential of this new diagnostic approach.

Soluble TIM-3 as a biomarker of progression and therapeutic response in cancers and other of human diseases

Immune checkpoints inhibition is a privileged approach to combat cancers and other human diseases. The TIM-3 (T cell immunoglobulin and mucin-domain containing-3) inhibitory checkpoint expressed on different types of immune cells is actively investigated as an anticancer target, with a dozen of monoclonal antibodies in (pre)clinical development. A soluble form sTIM-3 can be found in the plasma of patients with cancer and other diseases. This active circulating protein originates from the proteolytic cleavage by two ADAM metalloproteases of the membrane receptor shared by tumor and non-tumor cells, and extracellular vesicles. In most cancers but not all, overexpression of mTIM-3 at the cell surface leads to high level of sTIM-3. Similarly, elevated levels of sTIM-3 have been reported in chronic autoimmune diseases, inflammatory gastro-intestinal diseases, certain viral and parasitic diseases, but also in cases of organ transplantation and in pregnancy-related pathologies. We have analyzed the origin of sTIM-3, its methods of dosage in blood or plasma, its presence in multiple diseases and its potential role as a biomarker to follow disease progression and/or the treatment response. In contrast to sPD-L1 generated by different classes of proteases and by alternative splicing, sTIM-3 is uniquely produced upon ADAM-dependent shedding, providing a more homogenous molecular entity and a possibly more reliable molecular marker. However, the biological functionality of sTIM-3 remains insufficiently characterized. The review shed light on pathologies associated with an altered expression of sTIM-3 in human plasma and the possibility to use sTIM-3 as a diagnostic or therapeutic marker.

The Most Promising Biomarkers of Allogeneic Kidney Transplant Rejection

Clinical transplantology is a constantly evolving field of medicine. Kidney transplantation has become standard clinical practice, and it has a significant impact on reducing mortality and improving the quality of life of patients. Allogenic transplantation induces an immune response, which may lead to the rejection of the transplanted organ. The gold standard for evaluating rejection of the transplanted kidney by the recipient's organism is a biopsy of this organ. However, due to the high invasiveness of this procedure, alternative diagnostic methods are being sought. Therefore, the biomarkers may play an essential predictive role in transplant rejection. A review of the most promising biomarkers for early diagnosis and prognosis prediction of allogenic kidney transplant rejection summarizes novel data on neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), C-X-C motif chemokine 10 (CXCL-10), cystatin C (CysC), osteopontin (OPN), and clusterin (CLU) and analyses the dynamics of changes of the biomarkers mentioned above in kidney diseases and the mechanism of rejection of the transplanted kidney.

An Emerging Role of TIM3 Expression on T Cells in Chronic Kidney Inflammation

T cell immunoglobulin domain and mucin domain 3 (TIM3) was initially identified as an inhibitory molecule on IFNγ-producing T cells. Further research discovered the broad expression of TIM3 on different immune cells binding to multiple ligands. Apart from its suppressive effects on the Th1 cells, recent compelling experiments highlighted the indispensable role of TIM3 in the myeloid cell-mediated inflammatory response, supporting that TIM3 exerts pleiotropic effects on both adaptive and innate immune cells in a context-dependent manner. A large number of studies have been conducted on TIM3 biology in the disease settings of infection, cancer, and autoimmunity. However, there is a lack of clinical evidence to closely evaluate the role of T cell-expressing TIM3 in the pathogenesis of chronic kidney disease (CKD). Here, we reported an intriguing case of Mycobacterium tuberculosis (Mtb) infection that was characterized by persistent overexpression of TIM3 on circulating T cells and ongoing kidney tubulointerstitial inflammation for a period of 12 months. In this case, multiple histopathological biopsies revealed a massive accumulation of recruited T cells and macrophages in the enlarged kidney and liver. After standard anti-Mtb treatment, repeated renal biopsy identified a dramatic remission of the infiltrated immune cells in the tubulointerstitial compartment. This is the first clinical report to reveal a time-course expression of TIM3 on the T cells, which is pathologically associated with the progression of severe kidney inflammation in a non-autoimmunity setting. Based on this case, we summarize the recent findings on TIM3 biology and propose a novel model of CKD progression due to the aberrant crosstalk among immune cells.

Establishment of Galectin-3 Time-resolved Fluoroimmunoassay and its Application in Idiopathic Membranous Nephropathy

The aim of this study was to establish a time-resolved fluorescent immunoassay (TRFIA) for the detection of serum Galectin-3 (Gal-3) and apply this method to evaluate the clinical significance of serum Gal-3 in predicting Idiopathic Membranous Nephropathy (IMN) progression. The Gal-3-TRFIA was established using the double antibody sandwich method, with the capture antibodies coated on a 96-well microplate and the detection antibodies chelated with Europium (III) (Eu³⁺). Serum Gal-3 was detected in 81 patients with IMN and 123 healthy controls to further evaluate the value of the Gal-3 in staging of IMN. The sensitivity of the Gal-3-TRFIA assay was 0.85 ng/mL, and the detection range was 0.85-1000 ng/mL. The Gal-3 intra-batch and inter-batch coefficients of variation were 3.45% and 5.12%, respectively. The correlation coefficient (R) between the Gal-3-TRFIA assay and commercially available enzyme-linked immunosorbent assay kits was 0.83. The serum Gal-3 concentration was higher in patients with IMN (65.57 ± 55.90 ng/mL) compared to healthy controls (16.29 ± 9.91 ng/mL, P < 0.0001). In this study, a wide detection range Gal-3-TRFIA assay was developed using lanthanide (Eu³⁺) chelates for the detection of Gal-3 concentrations in serum. Gal-3 concentration is elevated in patients with IMN.

Soluble Tim-3/Gal-9 as predictors of adverse outcomes after kidney transplantation: a cohort study

BACKGROUND

In our previous study, serum soluble T-cell immunoglobulin and mucin structure-3 (stim-3) and galactosin-9 (sGal-9) were found to be associated with renal function after kidney transplantation. However, it is unclear whether these two indicators can predict adverse outcomes after transplantation.

METHODS

Ninety-one recipients of kidney transplantation were enrolled and divided into a stable group and an adverse outcome group (consisting of biopsy-proven rejection, graft loss, death and clinically diagnosed rejection). The expression levels of sTim-3 and sGal-9 before (pre-Tim-3 and pre-Gal-9) and one month after transplantation (post-Tim-3 and post-Gal-9) were measured by ELISA.

RESULTS

The level of pre-Tim-3 was significantly higher in the stable group than in the adverse outcome group [median (range), 2275 (840-4236) pg/mL vs. 1589 (353-3094) pg/mL, P=0.002]. The level of post-Gal-9 was significantly lower in the stable group than in the adverse outcome group [median (range), 4869 (1418-13080) pg/mL vs. 6852: (4128-10760) pg/mL, P=0.003]. The areas under the curve (AUCs) for pre-Tim-3 and post-Gal-9 were 0.737 (P=0.002) and 0.751 (P=0.003), respectively, better than AUC of post-eGFR (0.633) (P=0.071), according to the receiver operating characteristic (ROC) curve. Through Cox regression analysis, including pre-Tim-3, post-Gal-9, post-eGFR, sex, age, BMI of recipients and donors, pre-Tim-3 and post-Gal-9 were independent risk factors for adverse outcomes after kidney transplantation (P=0.016, P=0.033, respectively).

CONCLUSION

Serum sTim-3 and sGal-9 can predict adverse outcomes within two years after kidney transplantation.

Kidney Injury Molecule 1 (KIM-1): a Multifunctional Glycoprotein and Biological Marker (Review)

KIM-1 (kidney injury molecule 1) is a transmembrane glycoprotein also known as HAVcr-1 and TIM-1 belongs to the T-cell immunoglobulin and mucin domain family (TIM) of proteins. TIM glycoproteins are presented on the immune cells and participate in the regulation of immune reactions. KIM-1 differs from other members of its family in that it is expressed not only by immunocompetent cells but epithelial cells as well. Cellular and humoral effects mediated by KIM-1 are involved in a variety of physiological and pathophysiological processes.

Current understanding of the mechanisms determining the participation of KIM-1 in viral invasion, the immune response regulation, adaptive reactions of the kidney epithelium to acute ischemic or toxic injury, in progression of chronic renal diseases, and kidney cancer development have been presented in this review. Data of clinical researches demonstrating the association of KIM-1 with viral diseases and immune disorders have also been analyzed. Potential application of KIM-1 as urinary or serological marker in renal and cardiovascular diseases has been considered.

Expanding the Non-Invasive Diagnosis of Acute Rejection in Kidney Transplants Through Detection of Donor-Derived DNA in Urine: Proof-of-Concept Study

Background

Approximately 10%-20% of kidney transplant (KT) recipients suffer from acute rejection (AR); thus, sensitive and accurate monitoring of allograft status is recommended. We evaluated the clinical utility of donor-derived DNA (dd-DNA) detection in the urine of KT recipients as a non-invasive means for diagnosing AR.

Methods

Urine samples serially collected from 39 KT recipients were tested for 39 single-nucleotide variant loci selected according to technical criteria (i.e., high minor allele frequency and low analytical error) using next-generation sequencing. The fraction of dd-DNA was calculated and normalized by the urine creatinine (UCr) level (%dd-DNA/UCr). The diagnostic performance of %dd-DNA/UCr for AR was assessed by ROC curve analysis.

Results

There was an increasing trend of %dd-DNA/UCr in the AR group before subsequent graft injury, which occurred before (median of 52 days) histological rejection. The serum creatinine (SCr) level differed significantly between the AR and non-AR groups at two and four months of follow-up, whereas %dd-DNA/UCr differed between the groups at six months of follow-up. The combination of %dd-DNA/UCr, SCr, and spot urine protein (UPtn)/UCr showed high discriminating power, with an area under the ROC curve of 0.93 (95% confidence interval: 0.81-1.00) and a high negative predictive value of 100.0%.

Conclusions

Although the dd-DNA-based test cannot eliminate the need for biopsy, the high negative predictive value of this marker could increase the prebiopsy probability of detecting treatable injury to make biopsy an even more effective diagnostic tool.

Urinary mRNA Expression of Glomerular Podocyte Markers in Glomerular Disease and Renal Transplant

The research of novel markers in urinary samples, for the description of renal damage, is of high interest, and several works demonstrated the value of urinary mRNA quantification for the search of events related to renal disease or affecting the outcome of transplant kidneys. In the present pilot study, a comparison of the urine mRNA expression of specific podocyte markers among patients who had undergone clinical indication to renal transplanted (RTx, n = 20) and native (N, n = 18) renal biopsy was performed. The aim of this work was to identify genes involved in podocytes signaling and cytoskeletal regulation (NPHS1, NPHS2, SYNPO, WT1, TRPC6, GRM1, and NEUROD) in respect to glomerular pathology. We considered some genes relevant for podocytes signaling and for the function of the glomerular filter applying an alternative normalization approach. Our results demonstrate the WT1 urinary mRNA increases in both groups and it is helpful for podocyte normalization. Furthermore, an increase in the expression of TRPC6 after all kinds of normalizations was observed. According to our data, WT1 normalization might be considered an alternative approach to correct the expression of urinary mRNA. In addition, our study underlines the importance of slit diaphragm proteins involved in calcium disequilibrium, such as TRPC6.

Non-Invasive Diagnosis for Acute Rejection Using Urinary mRNA Signature Reflecting Allograft Status in Kidney Transplantation

Urine has been regarded as a good resource based on the assumption that urine can directly reflect the state of the allograft or ongoing injury in kidney transplantation. Previous studies, suggesting the usefulness of urinary mRNA as a biomarker of acute rejection, imply that urinary mRNA mirrors the transcriptional activity of the kidneys. We selected 14 data-driven candidate genes through a meta-analysis and measured the candidate genes using quantitative PCR without pre-amplification in the cross-sectional specimens from Korean kidney transplant patients. Expression of 9/14 genes (CXCL9, CD3ϵ, IP-10, LCK, C1QB, PSMB9, Tim-3, Foxp3, and FAM26F) was significantly different between acute rejection and stable graft function with normal pathology and long-term graft survival in 103 training samples. CXCL9 was also distinctly expressed in allografts with acute rejection in in situ hybridization analysis. This result, consistent with the qPCR result, implies that urinary mRNA could reflect the magnitude of allograft injury. We developed an AR prediction model with the urinary mRNAs by a binary logistic regression and the AUC of the model was 0.89 in the training set. The model was validated in 391 independent samples, and the AUC value yielded 0.84 with a fixed manner. In addition, the decision curve analysis indicated a range of reasonable threshold probabilities for biopsy. Therefore, we suggest the urine mRNA signature could be used as a non-invasive monitoring tool of acute rejection for clinical application and could help determine whether to perform a biopsy in a recipient with increased creatinine.

Tackling Chronic Kidney Transplant Rejection: Challenges and Promises

Despite advances in post-transplant management, the long-term survival rate of kidney grafts and patients has not improved as approximately forty percent of transplants fails within ten years after transplantation. Both immunologic and non-immunologic factors contribute to late allograft loss. Chronic kidney transplant rejection (CKTR) is often clinically silent yet progressive allogeneic immune process that leads to cumulative graft injury, deterioration of graft function. Chronic active T cell mediated rejection (TCMR) and chronic active antibody-mediated rejection (ABMR) are classified as two principal subtypes of CKTR. While significant improvements have been made towards a better understanding of cellular and molecular mechanisms and diagnostic classifications of CKTR, lack of early detection, differential diagnosis and effective therapies continue to pose major challenges for long-term management. Recent development of high throughput cellular and molecular biotechnologies has allowed rapid development of new biomarkers associated with chronic renal injury, which not only provide insight into pathogenesis of chronic rejection but also allow for early detection. In parallel, several novel therapeutic strategies have emerged which may hold great promise for improvement of long-term graft and patient survival. With a brief overview of current understanding of pathogenesis, standard diagnosis and challenges in the context of CKTR, this mini-review aims to provide updates and insights into the latest development of promising novel biomarkers for diagnosis and novel therapeutic interventions to prevent and treat CKTR.

Prediction of acute renal allograft rejection by combined HLA-G 14-bp insertion/deletion genotype analysis and detection of kidney injury molecule-1 and osteopontin in the peripheral blood

INTRODUCTION

Acute renal rejection usually fails to be diagnosed before the increase in the serum creatinine levels, and the resultant damage to the renal tissues occur in varying degrees. We hypothesized that the combined detection of human leucocyte antigen-G (HLA-G) 14-bp insertion/deletion genotypes and kidney injury molecule-1 (KIM-1) and osteopontin (OPN) levels in serum might facilitate the prediction of acute renal allograft rejections in kidney transplant recipients.

METHODS

HLA-G 14-bp insertion/deletion genotypes and the serum KIM-1 and OPN levels of 77 kidney transplant recipients were determined and compared before operation and on days 1, 4, and 7 after the operation (32 in acute rejection [AR] group and 45 in stable allograft function [STA] group). These 3 indicators were combined to establish a model for the early prediction of AR.

RESULTS

The KIM-1 levels in the serum of patients were significantly higher in the AR group than in the STA group. The area under the receiver operator characteristics (ROC) curve (AUC) of KIM-1 for the prediction of rejection was maximized on the1st day after operation, with a sensitivity of 84.4% and a specificity of 86.7%. The OPN levels in the serum of patients were significantly higher in the AR group than in the STA group only before operation and on the 7th day after operation. The AUC of OPN for the prediction of rejection was maximized on 7th day after operation, with a sensitivity of 68.8% and a specificity of 88.9%. The HLA-G + 14-bp allele frequency was also significantly higher in the AR group than in the STA group. The results of these three indicators were converted into a qualitative method. If any two of the three indicators show as positive, it was diagnosed as acute rejection, and it has the highest ability to predict acute rejection with a sensitivity and specificity of 84.38% and 91.11%, respectively.

CONCLUSIONS

The HLA-G 14-bp insertion/deletion genotype and KIM-1 and OPN levels in the patients' serum were significantly different between the AR and STA groups. The power of predicting acute renal allograft rejection could be improved by combined these three biomarkers.

Soluble Tim3 detection by time-resolved fluorescence immunoassay and its application in membranous nephropathy

Background

We aimed to develop a time‐resolved fluorescence immunoassay (TRFIA) for detecting soluble T‐cell immunoglobulin and mucin domain 3 (sTim3) in serum samples and to demonstrate a preliminary application of this method in membranous nephropathy (MN).

Methods

sTim3 TRFIA was developed, and the sTim3 concentration in the serum of patients with MN and healthy individuals was detected using a sandwich method.

Results

The sensitivity of the developed sTim3 TRFIA was 0.66 ng/mL, higher than that of an enzyme‐linked immunosorbent assay (ELISA) (1.11 ng/mL). The detection range was 0.66‐40 ng/mL. The intra‐assay coefficient of variation (CV) for sTim3 was 1.64%‐4.68%, and the inter‐assay CV was 5.72%‐9.32%. The cross‐reactivity to interleukin 6 (IL‐6) and kidney injury molecule 1 (KIM‐1) was 0.25% and 0.04%, respectively. The average recovery was 105.26%. The sTim3 concentration in patients with MN was considerably higher than that in healthy individuals (P < .001). The sTim3 concentration in the serum of patients with MN was significantly increased from G1 to G4 based on the Jonckheere‐Terpstra test (P < .001). Thus, we used sTim3 as a diagnostic indicator for distinguishing between healthy individuals and patients with MN as well as between different stages of MN.

Conclusion

We successfully established TRFIA to detect sTim3 in serum. We then applied this method to patients with MN, demonstrating for the first time that TRFIA is a valid diagnostic tool to detect sTim3 in serum.

Prognostic value of serum and urine kidney injury molecule-1 in infants with urinary tract infection

Introduction

Kidney injury molecule-1 (KIM-1) is an important diagnostic and prognostic marker in acute kidney injury and chronic kidney disease of various aetiologies. The aim of the study was to evaluate the usefulness of serum KIM-1 (sKIM-1) and urine KIM-1 (uKIM-1) for predicting febrile and non-febrile urinary tract infection (UTI) in infants.

Material and methods

A prospective study included 101 children divided into three groups: febrile UTI 49 children, non-febrile UTI 22 children, and healthy controls 30 children. The following laboratory tests were performed: sKIM-1, uKIM-1, white blood count (WBC), C-reactive protein (CRP), and procalcitonin (PCT).

Results

Median levels of sKIM-1 were significantly higher in the febrile and non-febrile UTI group compared to the healthy controls (both p < 0.05). Mean levels of uKIM-1 were significantly lower in the febrile UTI group compared to the non-febrile UTI group and healthy controls (p < 0.001 and p < 0.0001, respectively). Univariate logistic regression analysis has demonstrated a positive association of sKIM-1 with febrile and non-febrile UTI (both p < 0.05), and negative association uKIM-1 with febrile UTI (p < 0.0001). Receiver operating curve (ROC) analysis showed good diagnostic profiles of uKIM-1 with a best cut-off value of 2.4 ng/ml and sKIM-1 with a best cut-off value of 3.88 ng/ml for predicting febrile UTI (area under the curve [AUC] 0.82 and 0.67, sensitivity 73% and 63%, specificity 86% and 80%, respectively).

Conclusions

sKIM-1 can be useful for predicting febrile UTI. We do not recommended use of uKIM-1 as a marker of febrile UTI because of its negative association with febrile UTI. Both markers are not useful for predicting non-febrile UTI.

Assessment of serum Tim-3 and Gal-9 levels in predicting the risk of infection after kidney transplantation

Infection remains a major cause of morbidity and mortality after kidney transplantation (KT). Reliable biomarkers to predict post-transplant infection are lacking. We investigated the predictive performance of pre- and post-transplant levels of T-cell immunoglobulin and mucin domain-3 (Tim-3) and Galectin-9 (Gal-9), two pleiotropic immunomodulatory molecules, in early identification of infection. Serum Tim-3 and Gal-9 were paired measured before and 30 days after transplantation (PTD 30) in 95 KT recipients (KTRs). The decline rates of Tim-3 and Gal-9 were calculated relative to pre-transplant levels. KTRs with infection history had significantly higher levels of PTD 30 Tim-3 and Gal-9, and slower decrease rates of Gal-9 compared to non-infected recipients, while no difference was observed between two groups regarding pre-transplant levels. The AUCs for predicting 1-year post-transplant infection were 0.653 and 0.711 for post-transplant Tim-3 and Gal-9, 0.664 and 0.670 for relative Tim-3 and Gal-9, respectively. After adjusting for potential confounders, PTD 30 Tim-3, Gal-9 and relative Gal-9 remained as independent risk factors for post-transplant infection. Our results suggested that PTD 30 Tim-3 and Gal-9 and relative decrease of Gal-9 were promising predictors for identifying KTRs with high risk of infection, while pre-transplant Tim-3 and Gal-9 showed no predictive power to infection.

Sequential monitoring of TIM-3 mRNA expression in blood and urine samples of renal transplant recipients

BACKGROUND

T cell immunoglobulin and mucin domain 3 (TIM-3), as a co-inhibitory receptor expressed on Th1, Th17, CD8T, FoxP3 + Treg and innate immune cells, plays an important role in suppression of T cell-mediated immune responses, tolerance induction and T cell exhaustion. In this study, we evaluated sequential alterations of TIM-3 mRNA expression level in blood and urine samples of renal transplant recipients to predict approaching clinical episodes.

METHODS

A total of 52 adult renal transplant recipients (31 male and 21 female) were enrolled in this study. All the patients received kidney transplant from living unrelated donors. TIM-3 mRNA expression in peripheral blood mononuclear cells (PBMCs) and urinary cells were quantified using Real Time TaqMan polymerase chain reaction (PCR) at 4 different time points (pre-transplantation, 2, 90 and 180 days post-transplantation).

RESULT

TIM-3 mRNA expression level on days 2, 90 and 180 after transplantation was significantly higher in blood and urine samples of patients with graft dysfunction (GD) compared with patients with well-functioning graft (WFG). Our results also showed a high correlation between blood and urinary level of TIM-3 mRNA expression. The data from Receiver Operating Characteristic (ROC) Curve Analysis showed that blood and urinary TIM-3 mRNA expression level at month 3 and 6 could discriminate graft dysfunction (GD) from well-functioning graft (WFG) with high specificity and sensitivity.

CONCLUSION

Our data suggested that serial monitoring of TIM-3 mRNA level in the blood and urine samples of renal transplant recipients could be a useful non-invasive biomarker for prediction and diagnosis of allograft dysfunction.

Soluble Tim-3 and Gal-9 are associated with renal allograft dysfunction in kidney transplant recipients: A cross-sectional study

BACKGROUND

T cell immunoglobulin mucin-3 (Tim-3) has been reported to participate in the regulation of immune response and the induction of allograft tolerance. However, the association between Tim-3 and renal allograft dysfunction is unclear. We studied the expression of cellular and soluble Tim-3 (sTim-3), soluble galectin-9 (sGal-9) and carcinoembryonic antigen-related cell adhesion molecule-1 (sCEACAM-1) in kidney transplantation recipients (KTRs) to explore their roles in allograft dysfunction.

METHODS

96 KTRs (53 with stable graft and 43 with graft dysfunction) and 30 healthy controls (HC) were enrolled. Among the KTRs, 55 used Tacrolimus (TAC) and 41 used Sirolimus (SRL). In the dysfunction group, 29 recipients have undergone graft biopsy and 14 were classified as biopsy-proven rejection (BPR). Cellular Tim-3 was determined by flow cytometry. sTim-3 was determined by ELISA. sGal-9 and sCEACAM-1 were determined by Bio-Plex® suspension array system.

RESULTS

KTRs with renal dysfunction showed significantly higher levels of sTim-3 and sGal-9 but similar levels of cellular Tim-3 and sCEACAM-1 compared with stable recipients. Correlation analysis revealed that estimated glomerular filtration rate (eGFR) was negatively associated with sTim-3 and sGal-9. Both BPR and non-BPR groups showed comparable levels of Tim-3, Gal-9 and CEACAM-1. Moreover, SRL group showed significantly higher levels of sCEACAM-1 than TAC and HC groups.

CONCLUSIONS

sTim-3 and sGal-9 were promising biomarkers for allograft dysfunction, but unable to differentiate allograft rejection from other causes of renal dysfunction in KTRs. Moreover, long-term administration of sirolimus would up-regulate sCEACAM-1 level, while exert similar regulatory effects on Tim-3 and Gal-9 compared to tacrolimus.