Heightened peripheral blood lymphocyte CD69 expression is neither sensitive nor specific as a noninvasive diagnostic test for renal allograft rejection

Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio Predict Acute Cellular Rejection in the Kidney Allograft

Background

Kidney transplantation is the treatment of choice for end stage kidney disease, but acute rejection remains a limiting factor in optimizing allograft and patient survival. Needle biopsy is the current standard of care for this diagnosis. The potential for complications with repeat biopsies limits the ability to obtain temporal immune surveillance of the allograft. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been shown to be strong predictors of inflammation and of worse prognosis in a variety of conditions.

Material/Methods

This is a single center retrospective case control study which included all patients who underwent a “for -cause biopsy” of a transplanted kidney. NLR and PLR were calculated 1 month prior, at the time, and 6 months and 1 year after the biopsy.

Results

A total of 159 biopsies were reviewed; 127 (79.9%) of these satisfied all inclusion and exclusion criteria, and 63.0% of the sample cohort (n=80) demonstrated acute cellular rejection (ACR). Patients without evidence of ACR had an average NLR of 26.8, which was approximately 7-fold greater than those patients with findings of ACR (P<0.01). A similar trend was found for PLR, where patients without ACR had a 5.5-fold greater PLR compared to those with rejection (P<0.01). The ROC showed AUC of 0.715 and 0.716 respectively. The NLR cutoff of 9.5 had a positive predictive value (PPV) of 80% and a negative predictive value (NPV) of 77.8%; the PLR cutoff of 380 had a PPV of 75% and a NPV of 100%.

Conclusions

This study showed that NLR and PLR are easily obtainable and reproducible predictors of ACR in the kidney allograft. Serial monitoring of these ratios will help identify subclinical inflammation before evidence of allograft dysfunction.

Increased expression of CD69 on T cells as an early immune marker for human cytomegalovirus reactivation in chronic lymphocytic leukemia patients

Reactivation of human cytomegalovirus (HCMV) remains a serious problem in immunosuppressed individuals. To investigate whether a change in the immune status can be used as an earlier marker for HCMV reactivation than the traditional PCR analysis, eight chronic lymphocytic leukemia (CLL) patients at risk for reactivation due to commencement of alemtuzumab (anti-CD52) treatment were longitudinally followed. Five series of consecutive weekly blood samples were immunophenotyped by flow cytometry to cover both the innate and adaptive immune responses. Concurrently, patients were monitored by PCR for HCMV reactivation. We found a minor upregulation of the early activation marker CD69 on NK cells immediately before HCMV was detected in circulation by PCR. Interestingly, for the specific immune response, CD69 was highly upregulated on CD3(+) T cells, especially for the CD8(+) subset, in the two patients experiencing an HCMV reactivation between 6 and 20 d before HCMV viremia was measured by PCR. Moreover, a CD4(+):CD8(+) ratio lower than 0.6 may indicate a trend toward an increased risk for viral reactivation. In conclusion, an increase in CD69 expression is a promising candidate as an early predictor of HCMV reactivation.

Peripheral blood sampling for the detection of allograft rejection: biomarker identification and validation

Currently, acute allograft rejection can only be detected reliably by deterioration of graft function confirmed by allograft biopsy. A huge drawback of this method of diagnosis is that substantial organ damage has already taken place at the time that rejection is diagnosed. Discovering and validating noninvasive biomarkers that predict acute rejection, and chronic allograft dysfunction, is of great importance. Many studies have investigated changes in the peripheral blood in an attempt to find biomarkers that reflect changes in the graft directly or indirectly. Herein, we will review the promises and limitations of the peripheral blood biomarkers that have been described in the literature so far.

Lymphocyte activation markers may predict the presence of donor specific alloreactivity in pediatric living related liver transplant recipients

This is an observational study with the primary objective to measure donor-specific immune responses by pediatric liver transplant (LT) recipients, using cell surface expression of lymphocyte activation markers and cytokine secretion in mixed lymphocyte reactions. The secondary objective was to demonstrate possible mechanism(s) involved in those who demonstrated donor-specific hyporesponsiveness. Study participants included 17 recipients, their respective parental donors, the non-donor parent, as well as unrelated third party individuals. Within the CD4(+) population, two distinct patterns of CD69 and CD71 expressions were observed: recipients who had a lower percentage of CD4(+)CD69(+) and CD4(+)CD71(+) cells after donor versus non-donor stimulation (therefore a donor/non-donor ratio <1); and recipients who had a higher percentage of CD4(+)CD69(+) and CD4(+)CD71(+) cells after donor versus non-donor stimulation (therefore a donor/non-donor ratio ≥1). Eight recipients had the above defined ratio of <1, with significantly decreased interferon-γ secretion after donor versus non-donor stimulation. CD4(+)CD25(hi.)CD127- regulatory T cells from these eight recipients suppressed donor and non-donor cell induced proliferation. Suppression of proliferation was partially abrogated by interleukin-2. In conclusion, CD69 and CD71 cell surface expression with interferon-γ secretion can be used to identify two distinct populations in pediatric LT recipients. Both active regulation and anergy underlie donor specific hyporesponsiveness.

Effects of the new immunosuppressive agent AEB071 on human immune cells

BACKGROUND. The novel immunosuppressive agent AEB071 is currently being evaluated for its capability to prevent rejection after kidney transplantation as a potential adjunct to calcineurin inhibitor-based regimen. AEB071 is a selective protein kinase C inhibitor and has been shown to be well tolerated in humans. We here present extensive in vitro studies that contribute to the understanding of AEB071 effects on human lymphocyte, natural killer (NK) cell and dendritic cell (DC) action.

METHODS

The impact of AEB071 on several T-cell activation and costimulatory markers was assessed. Furthermore, assays were performed to study the effect on T-cell proliferation and intracellular cytokine production. Additionally, the effect of AEB071 on DC maturation and their capacity to stimulate allogeneic T-cells was examined. Also, an evaluation of AEB071 effects on the lytic activity of human NK cells was performed.

RESULTS

We were able to show that T-cell proliferation and cytokine production rates are significantly reduced after AEB071 administration. Also, mitogen-induced T-cell activation characterized by expression levels of surface markers could be significantly inhibited. In contrast, the T-cell stimulatory capacity of AEB071-treated mature monocyte-derived DC (Mo-DC) is not reduced, and AEB071 administration does not prevent lipopolysaccharide (LPS)-induced Mo-DC maturation. It could be demonstrated that AEB071 significantly inhibited the cytotoxic activity of NK cells.

CONCLUSIONS

The promising immunosuppressive agent AEB071 has a strong impact on T-cell activation, proliferation and cytokine production as well as NK cell activity, but not DC maturation in vitro, and therefore, seems to function T-cell and NK cell specific via protein kinase C (PKC) inhibition.

Renal transplant rejection markers

Acute rejection is one of the key factors which determine long-term graft function and survival in renal transplant patients. Timely detection and treatment of rejection is therefore, an important goal in the post-transplant surveillance. The standard care with serum creatinine measurements and biopsy upon allograft dysfunction implies that acute rejection is detected in an advanced stage. Therefore, non-invasive monitoring for acute rejection by markers in blood and urine has been tried over the past decades. This review describes the requirements that should be met by non-invasive markers. The experience with single biomarkers and with newer approaches--mRNA expression analysis, metabolomics, and proteomics--will be discussed, including future directions of necessary research.

Lymphocyte propagation from biopsies of kidney allografts

Morphological evaluation of transplant biopsies, usually using the Banff classification, is the most important tool to diagnose rejection after kidney transplantation. However, morphological analysis only scores the amount and localisation of infiltrating cells, and studies show that up to 30% of grafts with a stable function display infiltration of lymphocytes consistent with acute cellular rejection. Methods to study the functional properties of the infiltrating lymphocytes are therefore needed. We applied a tissue culture system on biopsies from transplanted human kidneys, allowing infiltrating cells to propagate out from the tissue. Cells were then counted and subtyped by flow cytometry. The results were correlated to morphology. In total, 92 biopsies from 69 patients were analysed. For 14 patients, serial biopsies were available. In grafts with cellular or combined cellular and vascular rejection, the number of ex vivo propagated mononuclear cells was higher than from non-rejecting grafts. A similar pattern was seen for CD3(+) T cells as well as for T cells expressing CD25 or MHC class II antigens. However, the proportion of CD25(+) or MHC class II(+) T lymphocytes was similar in all groups (no rejection, vascular rejection, borderline changes, cellular rejection, combined cellular and vascular rejection). In all groups the number of CD4(+) cells was higher than the number of CD8(+) cells. The results confirm previous experimental studies showing that graft-infiltrating cells are possible to culture in vitro and that lymphocyte propagation correlates to acute cellular rejection. Tissue culturing is easy to perform and evaluate and can be used to determine and analyse the cellular immune response to allografts and may thus be used as a complement to morphological analyses.

Developing a tool for noninvasive monitoring of renal allografts

Renal transplantation has emerged as the therapy of choice for many patients with end-stage renal disease. One of the major goals is to tailor immunosuppressive therapy to the individual needs of every patient at every time point post transplant, balancing the risk for rejection and over-immunosuppression. Such individualized treatment will require assays that can detect harmful processes in the allograft early and that can be measured repeatedly. In this review, advantages and disadvantages of current assays to monitor renal allografts noninvasively and how proteomic technology might contribute to the development of novel biomarkers to improve patient management will be discussed.

Ageing and plasma adiponectin concentration in apparently healthy males and females

OBJECTIVE

It is well known that ageing is associated with several hormonal alterations. However, the consequence of ageing on the endocrine function of adipose tissue is not fully elucidated. Adiponectin is a new anti-inflammatory protein secreted exclusively by adipocytes and plays a protective role against insulin resistance and atherosclerosis. Therefore, the aim of present study was to estimate plasma adiponectin concentration in apparently healthy elderly subjects.

SUBJECTS

Fifty-eight women and 67 men aged 20-93 years were included in this study. Subjects were divided into three groups: younger than 50 years, between 50 and 70 years and older than 70 years of age.

MEASUREMENTS

Plasma adiponectin concentration was estimated by an enzyme-linked immunosorbant assay in blood samples withdrawn in the morning after overnight fasting. In males plasma testosterone and dehydroepiandrostendione sulphate concentrations were assessed by a radioimmunoassay method.

RESULTS

Plasma adiponectin concentration only tended to be higher in all elderly subjects (above 70 years) than in the group of all subjects aged between 50 and 70 and the group younger than 50 years of age (12.8 +/- 5.7; 9.9 +/- 5.7 and 10.7 +/- 5.4 microg/ml, respectively). Plasma adiponectin concentration was of similar magnitude in female subjects of these three groups (11.2 +/- 5.7; 11.2 +/- 6.8 and 11.7 +/- 4.9 microg/ml, respectively). In contrast, males over 70 years old are characterized by significantly higher plasma adiponectin (14.0 +/- 5.4 microg/ml) concentration than males between 50 and 70 years of age (8.9 +/- 4.7 microg/ml, P < 0.01) and males younger than 50 years of age (9.6 +/- 5.7 microg/ml, P < 0.05). In the entire studied group a significant but weak, positive correlation was found between plasma adiponectin concentration and age (tau = 0.12; P = 0.04). Additionally, significant correlation was found between plasma adiponectin concentration and age in males when analysed separately (tau = 0.28; P = 0.0007). Such correlation was not significant in females (tau = -0.06; P = 0.5).

CONCLUSIONS

Plasma adiponectin concentration in females did not change significantly with age. In contrast to females, elderly males over 70 years of age are characterized by significantly higher plasma adiponectin concentration than younger ones.

Biomarkers and surrogate endpoints in renal transplantation: present status and considerations for clinical trial design

Of major importance in clinical trials is the ability to predict individual patient outcome or endpoints using biomarkers, also known as variables or predictors, in as safe, efficient, and accurate a manner as possible. This review addresses the concepts and possible strategies for use of predictor and surrogate biomarkers in the design of clinical trials in renal transplantation. The statistical concepts apply equally well to other organ grafts.