Serum sCD30: A promising biomarker for predicting the risk of bacterial infection after kidney transplantation

The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

Immune dysregulation as a leading principle for lymphoma development in diverse immunological backgrounds

Lymphoma is a heterogeneous group of malignancies arising from lymphocytes, which poses a significant challenge in terms of diagnosis and treatment due to its diverse subtypes and underlying mechanisms. This review aims to explore the shared and distinct features of various forms of lymphoma predisposing conditions, with a focus on genetic, immunological and molecular aspects. While diseases such as autoimmune disorders, inborn errors of immunity and iatrogenic immunodeficiencies are biologically and immunologically distinct, each of these diseases results in profound immune dysregulation and a predisposition to lymphoma development. Interestingly, the increased risk is often skewed towards a particular subtype of lymphoma. Patients with inborn errors of immunity in particular present with extreme forms of lymphoma predisposition, providing a unique opportunity to study the underlying mechanisms. External factors such as chronic infections and environmental exposures further modulate the risk of lymphoma development. Common features of conditions predisposing to lymphoma include: persistent inflammation, recurrent DNA damage or malfunctioning DNA repair, impaired tumor surveillance and viral clearance, and dysregulation of fundamental cellular processes such as activation, proliferation and apoptosis. Our growing understanding of the underlying mechanisms of lymphomagenesis provides opportunities for early detection, prevention and tailored treatment of lymphoma development.

Preoperative CD52 Level Predicts Graft Survival following Kidney Transplantation

Several factors have been reported to affect graft survival following kidney transplantation. CD52 molecules may increase T cell proliferation and activation, which may contribute to acute graft rejection and graft survival. In the current study, we studied the possible value of preoperative CD52 levels in predicting graft survival following renal transplantation. Ninety-six patients with end-stage renal disease who had kidney transplantation were included in the study from our prospective cohort. Blood samples were taken one day before surgery, and plasma CD52 levels were measured using ELISA (Cloud-Clone Corp., Houston, TX, USA). Acute rejection, acute tubular necrosis, delayed graft function, graft loss, BK infection, cytomegalovirus infection, and graft survival were evaluated. The mean age of recipients was 50.08 ± 12.82 years, and 64.6% were male. The incidence of delayed graft function, acute rejection, graft loss (p < 0.01), BK virus infection, and serum creatinine levels were significantly higher in recipients with high preoperative CD52 levels six months after transplantation (p < 0.05). Kaplan-Meier analysis revealed that three-year graft survival was significantly higher in patients with low preoperative CD52 levels (p < 0.0001). Univariate and multivariate Cox regression analyses showed that serum creatinine levels (hazard ratio [HR] = 1.7, p < 0.05), acute rejection (HR = 2.919, p < 0.05), and preoperative CD52 levels (HR = 3.114, p < 0.05) were independent prognostic factors for graft survival after kidney transplantation. We showed that high preoperative CD52 levels are associated with higher rates of acute rejection, delayed graft function, and BK virus infection and lower rates of graft survival after kidney transplantation.

Expansion of Double-Negative T Cells in Patients before Liver Transplantation Correlates with Post-Transplant Infections

Liver transplantation (LTx) is currently the only effective therapy for patients with end-stage liver diseases, but post-transplant infection is a key issue for morbidity and mortality. In this study, we found that pre-transplant patients with an expansion of double-negative T (DNT) cells (CD3⁺CD4⁻CD8⁻ T cells) had an increased incidence of infections within the first 6 months after LTx. These DNT cells also negatively correlated with their CD4/CD8 ratio. Compared to patients who had no infections after LTx, these DNT cells expressed more CD25, especially in the memory compartment. The receiver operating characteristic (ROC) analysis showed that the threshold area under the ROC curve of DNT cells which could be used to distinguish LTx patients with post-transplant infections from patients without infections after LTx was 0.8353 (95% CI: 0.6591–1.000). The cut-off for the pre-LTx DNT cell level was 11.35%. Although patients with post-transplant infections had decreased levels of CD4/CD8 T cells, CD8⁺ T cells in these patients were more exhausted, with higher PD-1 expression and lower IFNγ secretion. The increased levels of DNT cells in patients with post-transplant infections were still observed 2 weeks after LTx, with higher proportions of memory DNT cells. In conclusion, increased levels of DNT cells in pre-LTx patients may be valuable for the prognosis of post-transplant infections, especially within the first 6 months after LTx.

Cerebrospinal fluid CXCL10 is associated with the presence of low level CSF HIV during suppressive antiretroviral therapy

Surrogate markers of HIV central nervous system (CNS) persistence are needed because direct HIV measurements from the CNS require specialized protocols and are not always detectable or quantifiable. We analyzed paired plasma and CSF samples from people with HIV (PWH) on suppressive therapy (ART) with a validated HIV single copy RNA assay. Two potential markers of CNS persistence were measured (CXCL10 and sCD30). We then examined associations with CSF HIV RNA positivity in univariable and multivariable analyses. Among 66 individuals, 18.2% had detectable CSF HIV. Individuals who had detectable HIV in CSF had higher CSF CXCL10 concentrations (median 514 pg/ml versus median 317 pg/ml, p = 0.019), but did not have significantly different CSF sCD30 concentrations (median 7.5 ng/ml versus median 7.6 ng/ml, p = 0.78). In the multiple logistic analysis, both higher CSF CXCL10 (p = 0.038) and plasma HIV detectability (p = 0.035) were significantly associated with detectable CSF HIV. Both sCD30 and CXCL10 correlated positively with NfL and NSE, two neuronal markers. This study demonstrates that CSF CXCL10 concentrations reflect low level HIV CNS persistence despite virologic suppression on ART. Given that it is readily detectable and quantifiable, this chemokine may be a promising biomarker to evaluate HIV eradication therapies that target the CNS.

Role of novel biomarkers in kidney transplantation

Clinical application of biomarkers is an integral component of transplant care. Clinicians and scientists alike are in search of better biomarkers than the current serologic (serum creatinine, donor-specific antibodies), urine-derived (urinalysis, urine protein), and histologic ones we now use. The science behind recent biomarker discovery spans across multiple molecular biologic disciplines, including transcriptomics, proteomics, and metabolomics. Innovative methodology and integration of basic and clinical approaches have allowed researchers to unearth molecular phenomena preceding clinical disease. Biomarkers can be classified in several ways. In this review, we have classified them via their origin and outcome: Primarily immunologic, i.e., representative of immune regulation and dysfunction and non-immunologic, pertaining to delayed graft function, cardiovascular events/mortality, infection, malignancy, post-transplant diabetes, graft, and patient survival. Novel biomarker uses to guide the diagnosis and management of transplant-related outcomes is a promising area of research. However, the use of biomarkers to predict outcomes after kidney transplantation is not well studied. In this review, we summarize the recent studies illustrating biomarker use and transplant outcomes.

Predictive tools to determine risk of infection in kidney transplant recipients

Introduction: Infection represents a major complication after kidney transplantation (KT). Therapeutic drug monitoring is essentially the only approach for the adjustment of immunosuppression in current practice, with suboptimal results. The implementation of immune monitoring strategies may contribute to minimizing the risk of adverse events attributable to over-immunosuppression without compromising graft outcomes.Areas covered: The present review (based on PubMed/MEDLINE searches from database inception to November 2019) is focused on immune biomarkers with no antigen specificity (non-pathogen-specific), including serum levels of immunoglobulins and complement factors, peripheral blood lymphocyte subpopulations, soluble CD30, intracellular ATP production by stimulated CD4⁺ T-cells, and other cell-based immune assays. We also summarized recent advances in the use of replication kinetics of latent viruses to assess the functionality of T-cell immunity, with focus on the nonpathogenic anelloviruses. Finally, the composite risk scores reported in the literature are critically discussed.Expert opinion: Notable efforts have been made to develop an enlarging repertoire of immune biomarkers and prediction models, although most of them still lack technical standardization and external validation. Preventive interventions based on these tools (prolongation of prophylaxis, tapering of immunosuppression, or immunoglobulin replacement therapy in hypogammaglobulinemic patients) remain to be defined, ideally in the context of controlled trials.

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.

TNF-α Production by Monocytes Stimulated With Epstein-Barr Virus-Peptides as a Marker of Immunosuppression-Related Adverse Events in Kidney Transplant Recipients

Introduction

Infections and cancers now outnumber rejection as a cause of morbidity in transplant recipients, likely as a result of over-immunosuppression. Currently, there is no clinical tool to detect over-immunosuppression. We recently reported that tumor necrosis factor alpha (TNF-α) production by CD14⁺CD16⁺ intermediate monocytes, following ex vivo stimulation by Epstein-Barr virus–peptides, could identify over-immunosuppressed patients.

Methods

We conducted a pilot study the assay using 142 peripheral blood mononuclear samples from a cohort of 71 kidney transplant recipients. Patients were classified as cases or controls according to the occurrence of opportunistic infection, recurring bacterial infections or de novo neoplasia in the 12 months following blood collection. We used both the classifier rule and a threshold of <73% of CD14⁺CD16⁺TNFα⁺ cells developed in a previous training set.

Results

Cases were detected with 83% sensitivity and 68% specificity. The negative predictive value of the assay was 89%. The hazard ratio for the occurrence of the endpoint was 6.8 (95% confidence interval 2.0–23.9; P = 0.003) in patients with a positive test. Multivariable linear regression analysis revealed that the association was independent of baseline clinical characteristics, renal function, and immunosuppressive regimen.

Conclusion

These data validate this cell-based assay as a promising tool for personalizing immunotherapy. Studies are under way for a 2-step assay with improved specificity.

Can immune biomarkers predict infections in solid organ transplant recipients? A review of current evidence

Despite improvements in graft survival, solid organ transplantation is still associated with considerable infection induced morbidity and mortality. If we were able to show that serious infection risk was associated with excessive suppression of immune capacity, we would be justified in "personalizing" the extent of immunosuppression by carefully monitored reduction to see if we can improve immune compromize without increasing the risk of rejection. Reliable biomarkers are needed to identify this patients at an increased risk of infection. This review focuses on the currently available evidence in solid organ transplant recipients for immune non-pathogen specific biomarkers to predict severe infections with the susceptibility to particular pathogens according to the component of the immune system that is suppressed. This review is categorized into immune biomarkers representative of the humoral, cellular, phagocytic, natural killer cell and complement system. Biomarkers humoral and cellular systems of the that have demonstrated an association with infections include immunoglobulins, lymphocyte number, lymphocyte subsets, intracellular concentrations of adenosine triphosphate in stimulated CD4⁺ cells and soluble CD30. Biomarkers of the innate immune system that have demonstrated an association with infections include natural killer cell numbers, complement and mannose binding lectin. Emerging evidence shows that quantification of viral nucleic acid (such as Epstein Barr Virus) can act as a biomarker to predict all-cause infections. Studies that show the most promise are those in which several immune biomarkers are assessed in combination. Ongoing research is required to validate non-pathogen specific immune biomarkers in multi-centre studies using standardized study designs.

In vitro intracellular IFNγ, IL-17 and IL-10 producing T cells correlates with the occurrence of post-transplant opportunistic infection in liver and kidney recipients

AIM

To validate intracellular cytokine production functional assay as means of cell-mediated immunity monitoring of post-transplant patients with opportunistic infection (OI).

METHODS

Intracellular cytokine-producing CD4⁺ and CD8⁺ T-cell monitoring was carried out in 30 liver transplant (LTr) and 31 kidney transplant (KTr) recipients from 2010 to 2012. Patients were assessed in our Department of Immunology at the Clinical University ‘Hospital Virgen de la Arrixaca-IMIB’ in Murcia, Spain for one year following transplantation. FACS Canto II flow cytometer was employed to quantify the intracellular production of IL-17, IFNγ and IL-10 cytokines on stimulated CD4⁺CD69⁺ and CD8⁺CD69⁺ T cells and BD FACS DIVA v.6 software was used to analysed the data. Statistical analysis was carried out using SPSS 22.0.

RESULTS

LTr with OI had significantly lower % of CD8⁺CD69⁺IFNγ⁺ T cells at 60 (7.95 ± 0.77 vs 26.25 ± 2.09, P < 0.001), 90 (7.47 ± 1.05 vs 30.34 ± 3.52, P < 0.001) and 180 (15.31 ± 3.24 vs 24.59 ± 3.28, P = 0.01) d post-transplantation. Higher % of CD4⁺CD69⁺IL-10⁺ as well as CD4⁺CD69⁺IL-17⁺ T cells were yet reported at 30 (14.06 ± 1.65 vs 6.09 ± 0.53, P = 0.0007 and 4.23 ± 0.56 vs 0.81 ± 0.14, P = 0.005; respectively), 60 (11.46 ± 1.42 vs 4.54 ± 0.91, P = 0.001 and 4.21 ± 0.59 vs 1.43 ± 0.42, P = 0.03; respectively) and 90 d (16.85 ± 1.60 vs 4.07 ± 0.63, P < 0.001 and 3.97 ± 0.43 vs 0.96 ± 0.17, P = 0.001). Yet, KTr with OI had significantly lower percentage of CD4⁺CD69⁺IFNγ⁺ at 30 (11.80 ± 1.59 vs 20.64 ± 3.26, P = 0.035), 60 (11.19 ± 1.35 vs 15.85 ± 1.58, P = 0.02), 90 (11.37 ± 1.42 vs 22.99 ± 4.12, P = 0.028) and 180 (13.63 ± 2.21 vs 21.93 ± 3.88, P = 0.008) d post-transplantation as opposed to CD4⁺CD69⁺IL-10⁺ and CD8⁺CD69⁺IL-10⁺ T cells which percentages were higher at 30 (25.21 ± 2.74 vs 8.54 ± 1.64, P < 0.001 and 22.37 ± 1.35 vs 17.18 ± 3.54, P = 0.032; respectively), 90 (16.85 ± 1.60 vs 4.07 ± 0.63, P < 0.001 and 23.06 ± 2.89 vs 10.19 ± 1.98, P = 0.002) and 180 (21.81 ± 1.72 vs 6.07 ± 0.98, P < 0.001 and 19.68 ± 2.27 vs 10.59 ± 3.17, P = 0.016) d post-transplantation. The auROC curve model determined the most accurate cut-off values to stratify LTr and KTr at high risk of OI and Cox Regression model confirmed these biomarkers as the most significant risk factors to opportunistic infection.

CONCLUSION

Post-transplant percentages of T-cell subsets differed significantly amongst infected- and non-infected-LTr and -KTr and yet this imbalance was found to contribute towards a worst clinical outcome.

Peritransplant Soluble CD30 as a Risk Factor for Slow Kidney Allograft Function, Early Acute Rejection, Worse Long-Term Allograft Function, and Patients' Survival

BACKGROUND

We aimed to determine whether serum soluble CD30 (sCD30) could identify recipients at high risk for unfavorable early and late kidney transplant outcomes.

METHODS

Serum sCD30 was measured on the day of kidney transplantation and on the 4th day posttransplant. We assessed the value of these measurements in predicting delayed graft function, slow graft function (SGF), acute rejection (AR), pyelonephritis, decline of allograft function after 6 months, and graft and patient survival during 5 years of follow-up in 45 recipients.

RESULTS

We found the association between low pretransplant serum levels of sCD30 and SGF. The absence of significant decrease of sCD30 on the 4th day posttransplant was characteristic for SGF, early AR (the 8th day-6 months), late AR (>6 months), and early pyelonephritis (the 8th day-2 months). Lower pretransplant and posttransplant sCD30 predicted worse allograft function at 6 months and 2 years, respectively. Higher pretransplant sCD30 was associated with higher frequency of early AR, and worse patients' survival, but only in the recipients of deceased-donor graft. Pretransplant sCD30 also allowed to differentiate patients with early pyelonephritis and early AR.

CONCLUSIONS

Peritransplant sCD30 is useful in identifying patients at risk for unfavorable early and late transplant outcomes.