Serum fractalkine and interferon-gamma inducible protein-10 concentrations are early detection markers for acute renal allograft rejection

Characterizing of intra-amniotic inflammatory changes associated with chronic inflammation in the placenta marked by elevated amniotic fluid interferon gamma-induced protein 10 (IP-10) in pregnancies complicated by preterm prelabor rupture of membranes

OBJECTIVES

This study aimed to determine the occurrence of intra-amniotic inflammatory changes associated with chronic inflammation in the placenta, marked by elevated levels of interferon gamma-induced protein 10 (IP-10) (≥2200 pg/mL) in the amniotic fluid of women with preterm prelabor rupture of membranes (PPROM). Specifically, the study investigated whether these intra-amniotic inflammatory changes were more common in women with microbial invasion of amniotic cavity (MIAC) and intra-amniotic inflammation (IAI), as indicated by increased amniotic fluid interleukin (IL)-6 concentration (≥3000 pg/mL).

STUDY DESIGN

A cohort of 114 women with singleton pregnancies complicated by PPROM between 24+0 and 36+6 weeks of gestation were included. Amniotic fluid samples were obtained via amniocentesis upon admission. MIAC diagnosis involved aerobic and anaerobic cultures, as well as polymerase chain reaction (PCR) analysis of the amniotic fluid. Immunoassay tests and enzyme-linked immunosorbent assay (ELISA) were used to determine IL-6 and IP-10 concentrations, respectively.

RESULTS

Among the participants, 19.3 % and 15.8 % had MIAC and IAI, respectively. The occurrence of intra-amniotic inflammatory changes associated with chronic inflammation in the placenta was similar between women with and without MIAC (25 % vs. 40.9 %, p = 0.136, adjusted p = 0.213). The rate of intra-amniotic inflammatory changes associated with chronic inflammation in the placenta was significantly higher in women with IAI compared to those without, after adjusting for gestational age at sampling (55.6 % vs. 22.9 %, p = 0.005, adjusted p = 0.011).

CONCLUSION

This study revealed comparable rates of intra-amniotic inflammatory changes associated with chronic inflammation in the placenta in women with and without MIAC, but a higher prevalence of intra-amniotic inflammatory changes associated with chronic inflammation in the placenta in women with IAI. These findings suggest involvement of chronic inflammation even in women with PPROM with acute intra-amniotic inflammation.

Role of the CX3CL1-CX3CR1 axis in renal disease

Excessive infiltration of immune cells into the kidney is a key feature of acute and chronic kidney diseases. The family of chemokines comprises key drivers of this process. Fractalkine [chemokine (C-X3-C motif) ligand 1 (CX3CL1)] is one of two unique chemokines synthesized as a transmembrane protein that undergoes proteolytic cleavage to generate a soluble species. Through interacting with its cognate receptor, chemokine (C-X3-C motif) receptor 1 (CX3CR1), CX3CL1 was originally shown to act as a conventional chemoattractant in the soluble form and as an adhesion molecule in the transmembrane form. Since then, other functions of CX3CL1 beyond leukocyte recruitment have been described, including cell survival, immunosurveillance, and cell-mediated cytotoxicity. This review summarizes diverse roles of CX3CL1 in kidney disease and potential uses as a therapeutic target and novel biomarker. As the CX3CL1-CX3CR1 axis has been shown to contribute to both detrimental and protective effects in various kidney diseases, a thorough understanding of how the expression and function of CX3CL1 are regulated is needed to unlock its therapeutic potential.

CX3CR1 at V249M and T280M Gene Polymorphism and Its Potential Risk for End-Stage Renal Diseases in Egyptian Patients

CX3CL1-CX3CR1 pathway may be one of the future treatment targets to delay the progression of end-stage renal diseases. This study aimed to evaluate the CX3CR gene polymorphism in Egyptian patients with ESRD and its relation to fractalkine blood level. The study included 100 patients with ESRD on dialysis, 61 males and 39 females with mean age 51.02 ± 7.8 years. The V2491 genotype revealed a significant increase in the frequency of GG genotype in healthy control (83%) compared to patients [69%] with a significant increase in GA in patients [30%] compared to control subjects [15%], P = 0.03. T280M study showed a statistically significant prevalence of TT genotype in healthy control subjects [86%-OR 95% CI 1.7] compared to patients [70%] with a significant increase in the prevalence of TA in patients [29%] compared to control subjects [13%], P = 0.01. There was a significant increase in fractalkine levels in genotypes GA + AA [503.04±224.1] pg/ml compared to genotype GG [423.6 210.3], P = 0.03. Moreover, there was a significant increase in the blood level of fractalkine in genotype TA + AA [498.8 219.6] compared to genotype TT [426.8±212.8], P = 0.05. In conclusion, our study showed that both V2491-GA genotype and T280M-TA are associated with potential risk for end-stage renal disease in Egyptian patients.

Macrophage depletion of CMV latently infected donor hearts ameliorates recipient accelerated chronic rejection

Cytomegalovirus (CMV) infection is linked to acceleration of solid organ transplant vascular sclerosis (TVS) and chronic rejection (CR). Donor latent CMV infection increases cardiac-resident macrophages and T cells leading to increased inflammation, promoting allograft rejection. To investigate the role of cardiac-resident passenger macrophages in CMV-mediated TVS/CR, macrophages were depleted from latently ratCMV (RCMV)-infected donor allografts prior to transplantation. Latently RCMV-infected donor F344 rats were treated with clodronate, PBS, or control liposomes 3 days prior to cardiac transplant into RCMV-naïve Lewis recipients. Clodronate treatment significantly increased graft survival from post-operative day (POD)61 to POD84 and decreased TVS at rejection. To determine the kinetics of the effect of clodronate treatment's effect, a time study revealed that clodronate treatment significantly decreased macrophage infiltration into allograft tissues as early as POD14; altered allograft cytokine/chemokine protein levels, fibrosis development, and inflammatory gene expression profiles. These findings support our hypothesis that increased graft survival as a result of allograft passenger macrophage depletion was in part a result of altered immune response kinetics. Depletion of donor macrophages prior to transplant is a strategy to modulate allograft rejection and reduce TVS in the setting of CMV + donors transplanted into CMV naïve recipients.

A pilot study evaluating GSK1070806 inhibition of interleukin-18 in renal transplant delayed graft function

INTRODUCTION

Delayed graft function (DGF) following renal transplantation is a manifestation of acute kidney injury (AKI) leading to poor long-term outcome. Current treatments have limited effectiveness in preventing DGF. Interleukin-18 (IL18), a biomarker of AKI, induces interferon-γ expression and immune activation. GSK1070806, an anti-IL18 monoclonal antibody, neutralizes activated (mature) IL18 released from damaged cells following inflammasome activation. This phase IIa, single-arm trial assessed the effect of a single dose of GSK1070806 on DGF occurrence post donation after circulatory death (DCD) kidney transplantation.

METHODS

The 3 mg/kg intravenous dose was selected based on prior studies and physiologically based pharmacokinetic (PBPK) modeling, indicating the high likelihood of a rapid and high level of IL18 target engagement when administered prior to kidney allograft reperfusion. Utilization of a Bayesian sequential design with a background standard-of-care DGF rate of 50% based on literature, and confirmed via extensive registry data analyses, enabled a statistical efficacy assessment with a minimal sample size. The primary endpoint was DGF frequency, defined as dialysis requirement ≤7 days post transplantation (except for hyperkalemia). Secondary endpoints included safety, pharmacokinetics and pharmacodynamic biomarkers.

RESULTS

GSK1070806 administration was associated with IL18-GSK1070806 complex detection and increased total serum IL18 levels due to IL18 half-life prolongation induced by GSK1070806 binding. Interferon-γ-induced chemokine levels declined or remained unchanged in most patients. Although the study was concluded prior to the Bayesian-defined stopping point, 4/7 enrolled patients (57%) had DGF, exceeding the 50% standard-of-care rate, and an additional two patients, although not reaching the protocol-defined DGF definition, demonstrated poor graft function. Six of seven patients experienced serious adverse events (SAEs), including two treatment-related SAEs.

CONCLUSION

Overall, using a Bayesian design and extensive PBPK dose modeling with only a small sample size, it was deemed unlikely that GSK1070806 would be efficacious in preventing DGF in the enrolled DCD transplant population.

TRIAL REGISTRATION

NCT02723786.

A novel approach reveals that HLA class 1 single antigen bead-signatures provide a means of high-accuracy pre-transplant risk assessment of acute cellular rejection in renal transplantation

BACKGROUND

Acute cellular rejection (ACR) is associated with complications after kidney transplantation, such as graft dysfunction and graft loss. Early risk assessment is therefore critical for the improvement of transplantation outcomes. In this work, we retrospectively analyzed a pre-transplant HLA antigen bead assay data set that was acquired by the e:KID consortium as part of a systems medicine approach.

RESULTS

The data set included single antigen bead (SAB) reactivity profiles of 52 low-risk graft recipients (negative complement dependent cytotoxicity crossmatch, PRA < 30%) who showed detectable pre-transplant anti-HLA 1 antibodies. To assess whether the reactivity profiles provide a means for ACR risk assessment, we established a novel approach which differs from standard approaches in two aspects: the use of quantitative continuous data and the use of a multiparameter classification method. Remarkably, it achieved significant prediction of the 38 graft recipients who experienced ACR with a balanced accuracy of 82.7% (sensitivity = 76.5%, specificity = 88.9%).

CONCLUSIONS

The resultant classifier achieved one of the highest prediction accuracies in the literature for pre-transplant risk assessment of ACR. Importantly, it can facilitate risk assessment in non-sensitized patients who lack donor-specific antibodies. As the classifier is based on continuous data and includes weak signals, our results emphasize that not only strong but also weak binding interactions of antibodies and HLA 1 antigens contain predictive information.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00724022 . Retrospectively registered July 2008.

Cytokine-Mediated Induction and Regulation of Tissue Damage During Cytomegalovirus Infection

Human cytomegalovirus (HCMV) is a β-herpesvirus with high sero-prevalence within the human population. Primary HCMV infection and life-long carriage are typically asymptomatic. However, HCMV is implicated in exacerbation of chronic conditions and associated damage in individuals with intact immune systems. Furthermore, HCMV is a significant cause of morbidity and mortality in the immunologically immature and immune-compromised where disease is associated with tissue damage. Infection-induced inflammation, including robust cytokine responses, is a key component of pathologies associated with many viruses. Despite encoding a large number of immune-evasion genes, HCMV also triggers the induction of inflammatory cytokine responses during infection. Thus, understanding how cytokines contribute to CMV-induced pathologies and the mechanisms through which they are regulated may inform clinical management of disease. Herein, we discuss our current understanding based on clinical observation and in vivo modeling of disease of the role that cytokines play in CMV pathogenesis. Specifically, in the context of the different tissues and organs in which CMV replicates, we give a broad overview of the beneficial and adverse effects that cytokines have during infection and describe how cytokine-mediated tissue damage is regulated. We discuss the implications of findings derived from mice and humans for therapeutic intervention strategies and our understanding of how host genetics may influence the outcome of CMV infections.

Multiple-biomarkers provide powerful prediction of early acute renal allograft rejection by combination of serum fractalkine, IFN-γ and IP-10

Biomarkers are urgently required for predicting rejection so that anti-rejection treatment can be taken early to protect the allograft from irreversible damage. We hypothesized that the combination of circulating fractalkine, IFN-γ and IP-10 might serve as effective biomarkers for predicting early acute renal allograft rejection. We conducted a retrospective study of 87 subjects, who were classified into acute rejection group (ARG; n = 38) and non-rejection group (NRG; n = 49). Serum fractalkine, IFN-γ and IP-10 levels were measured by Luminex. The levels of fractalkine on day 0 and 7th day, IP-10 on 4th and 7th day, and IFN-γ on 7th day in ARG was significantly higher than that in NRG. Kaplan-Meier survival analysis highlighted the higher-levels groups of fractalkine on day 0, 4th and 7th day, IFN-γ on day 0, 1st, 4th, and 7th day and IP-10 on the 4th and 7th day in rejection-free survival probability were significantly lower than low-levels groups. ROC analyses highlight the superiority of fractalkine on day 0, IP-10 on day 0, 4th and 7th day, and IFN-γ on day 0, 1st and 7th day in prediction of acute rejection. We found the combination of fractalkine on day 0, IP-10 on 7th day and IFN-γ on 7th day had the highest AUC (0.866) for predicting rejection with a sensitivity of 86.8% and a specificity of 89.8%. Our findings demonstrated a more powerful prediction of early acute renal allograft rejection during the first month after transplantation by combination of multiple-biomarkers of fractalkine, IFN-γ and IP-10, and the results might help stratify the immunologic risk of acute allograft rejection in recipients.

Chronic inflammatory lesions of the placenta are associated with an up-regulation of amniotic fluid CXCR3: A marker of allograft rejection

OBJECTIVE

The objective of this study is to determine whether the amniotic fluid (AF) concentration of soluble CXCR3 and its ligands CXCL9 and CXCL10 changes in patients whose placentas show evidence of chronic chorioamnionitis or other placental lesions consistent with maternal anti-fetal rejection.

METHODS

This retrospective case-control study included 425 women with (1) preterm delivery (n=92); (2) term in labor (n=68); and (3) term not in labor (n=265). Amniotic fluid CXCR3, CXCL9 and CXCL10 concentrations were determined by ELISA.

RESULTS

(1) Amniotic fluid concentrations of CXCR3 and its ligands CXCL9 and CXCL10 are higher in patients with preterm labor and maternal anti-fetal rejection lesions than in those without these lesions [CXCR3: preterm labor and delivery with maternal anti-fetal rejection placental lesions (median, 17.24 ng/mL; IQR, 6.79-26.68) vs. preterm labor and delivery without these placental lesions (median 8.79 ng/mL; IQR, 4.98-14.7; P=0.028)]; (2) patients with preterm labor and chronic chorioamnionitis had higher AF concentrations of CXCL9 and CXCL10, but not CXCR3, than those without this lesion [CXCR3: preterm labor with chronic chorioamnionitis (median, 17.02 ng/mL; IQR, 5.57-26.68) vs. preterm labor without chronic chorioamnionitis (median, 10.37 ng/mL; IQR 5.01-17.81; P=0.283)]; (3) patients with preterm labor had a significantly higher AF concentration of CXCR3 than those in labor at term regardless of the presence or absence of placental lesions.

CONCLUSION

Our findings support a role for maternal anti-fetal rejection in a subset of patients with preterm labor.

CXCL10 and IL-6: Markers of two different forms of intra-amniotic inflammation in preterm labor

Problem

To determine whether amniotic fluid (AF) CXCL10 concentration is associated with histologic chronic chorioamnionitis in patients with preterm labor (PTL) and preterm prelabor rupture of the membranes (PROM).

Method of Study

This study included 168 women who had an episode of PTL or preterm PROM. AF interleukin (IL)‐6 and CXCL10 concentrations were determined by immunoassay.

Results

(i) Increased AF CXCL10 concentration was associated with chronic (OR: 4.8; 95% CI: 1.7‐14), but not acute chorioamnionitis; (ii) increased AF IL‐6 concentration was associated with acute (OR: 4.2; 95% CI: 1.3‐13.7) but not chronic chorioamnionitis; and (iii) an increase in AF CXCL10 concentration was associated with placental lesions consistent with maternal anti‐fetal rejection (OR: 3.7; 95% CI: 1.3‐10.4). (iv) All patients with elevated AF CXCL10 and IL‐6 delivered preterm.

Conclusion

Increased AF CXCL10 concentration is associated with chronic chorioamnionitis or maternal anti‐fetal rejection, whereas increased AF IL‐6 concentration is associated with acute histologic chorioamnionitis.

CX3CL1/CX3CR1 Axis, as the Therapeutic Potential in Renal Diseases: Friend or Foe?

The fractalkine receptor chemokine (C-X3-C motif) receptor 1 (CX3CR1) and its highly selective ligand CX3CL1 mediate chemotaxis and adhesion of immune cells, which are involved in the pathogenesis and progression of numerous inflammatory disorders and malignancies. The CX3CL1/CX3CR1 axis has recently drawn attention as a potential therapeutic target because it is involved in the ontogeny, homeostatic migration, or colonization of renal phagocytes. We performed a Medline/PubMed search to detect recently published studies that explored the relationship between the CX3CL1/CX3CR1 axis and renal diseases and disorders, including diabetic nephropathy, renal allograft rejection, infectious renal diseases, IgA nephropathy, fibrotic kidney disease, lupus nephritis and glomerulonephritis, acute kidney injury and renal carcinoma. Most studies demonstrated its role in promoting renal pathopoiesis; however, several recent studies showed that the CX3CL1/CX3CR1 axis could also reduce renal pathopoiesis. Thus, the CX3CL1/CX3CR1 axis is now considered to be a double-edged sword that could provide novel perspectives into the pathogenesis and treatment of renal diseases and disorders.

Non-invasive approaches in the diagnosis of acute rejection in kidney transplant recipients, part II: omics analyses of urine and blood samples

Kidney transplantation (KTx) represents the best available treatment for patients with end-stage renal disease. Still, the full benefits of KTx are undermined by acute rejection (AR). The diagnosis of AR ultimately relies on transplant needle biopsy. However, such an invasive procedure is associated with a significant risk of complications and is limited by sampling error and interobserver variability. In the present review, we summarize the current literature about non-invasive approaches for the diagnosis of AR in kidney transplant recipients (KTRs), including in vivo imaging, gene-expression profiling and omics analyses of blood and urine samples. Most imaging techniques, such as contrast-enhanced ultrasound and magnetic resonance, exploit the fact that blood flow is significantly lowered in case of AR-induced inflammation. In addition, AR-associated recruitment of activated leucocytes may be detectable by 18F-fluorodeoxyglucose positron emission tomography. In parallel, urine biomarkers, including CXCL9/CXCL10 or a three-gene signature of CD3ε, CXCL10 and 18S RNA levels, have been identified. None of these approaches has yet been adopted in the clinical follow-up of KTRs, but standardization of analysis procedures may help assess reproducibility and comparative diagnostic yield in large, prospective, multicentre trials.

Chronic inflammation of the placenta: definition, classification, pathogenesis, and clinical significance

Chronic inflammatory lesions of the placenta are characterized by the infiltration of the organ by lymphocytes, plasma cells, and/or macrophages and may result from infections (viral, bacterial, parasitic) or be of immune origin (maternal anti-fetal rejection). The 3 major lesions are villitis (when the inflammatory process affects the villous tree), chronic chorioamnionitis (which affects the chorioamniotic membranes), and chronic deciduitis (which involves the decidua basalis). Maternal cellular infiltration is a common feature of the lesions. Villitis of unknown etiology (VUE) is a destructive villous inflammatory lesion that is characterized by the infiltration of maternal T cells (CD8+ cytotoxic T cells) into chorionic villi. Migration of maternal T cells into the villi is driven by the production of T-cell chemokines in the affected villi. Activation of macrophages in the villi has been implicated in the destruction of the villous architecture. VUE has been reported in association with preterm and term fetal growth restriction, preeclampsia, fetal death, and preterm labor. Infants whose placentas have VUE are at risk for death and abnormal neurodevelopmental outcome at the age of 2 years. Chronic chorioamnionitis is the most common lesion in late spontaneous preterm birth and is characterized by the infiltration of maternal CD8+ T cells into the chorioamniotic membranes. These cytotoxic T cells can induce trophoblast apoptosis and damage the fetal membranes. The lesion frequently is accompanied by VUE. Chronic deciduitis consists of the presence of lymphocytes or plasma cells in the basal plate of the placenta. This lesion is more common in pregnancies that result from egg donation and has been reported in a subset of patients with premature labor. Chronic placental inflammatory lesions can be due to maternal anti-fetal rejection, a process associated with the development of a novel form of fetal systemic inflammatory response. The syndrome is characterized by an elevation of the fetal plasma T-cell chemokine. The evidence that maternal anti-fetal rejection underlies the pathogenesis of many chronic inflammatory lesions of the placenta is reviewed. This article includes figures and histologic examples of all chronic inflammatory lesions of the placenta.