Granulysin expression is a marker for acute rejection and steroid resistance in human renal transplantation

Involvement of M1-Activated Macrophages and Perforin/Granulysin Expressing Lymphocytes in IgA Vasculitis Nephritis

We investigated the polarisation of CD68+ macrophages and perforin and granulysin distributions in kidney lymphocyte subsets of children with IgA vasculitis nephritis (IgAVN). Pro-inflammatory macrophage (M)1 (CD68/iNOS) or regulatory M2 (CD68/arginase-1) polarisation; spatial arrangement of macrophages and lymphocytes; and perforin and granulysin distribution in CD3+ and CD56+ cells were visulaised using double-labelled immunofluorescence. In contrast to the tubules, iNOS+ cells were more abundant than the arginase-1+ cells in the glomeruli. CD68+ macrophage numbers fluctuated in the glomeruli and were mostly labelled with iNOS. CD68+/arginase-1+ cells are abundant in the tubules. CD56+ cells, enclosed by CD68+ cells, were more abundant in the glomeruli than in the tubuli, and co-expressed NKp44. The glomerular and interstitial/intratubular CD56+ cells express perforin and granulysin, respectively. The CD3+ cells did not express perforin, while a minority expressed granulysin. Innate immunity, represented by M1 macrophages and CD56+ cells rich in perforin and granulysin, plays a pivotal role in the acute phase of IgAVN.

Novel transcriptomic signatures associated with premature kidney allograft failure

BACKGROUND

The power to predict kidney allograft outcomes based on non-invasive assays is limited. Assessment of operational tolerance (OT) patients allows us to identify transcriptomic signatures of true non-responders for construction of predictive models.

METHODS

In this observational retrospective study, RNA sequencing of peripheral blood was used in a derivation cohort to identify a protective set of transcripts by comparing 15 OT patients (40% females), from the TOMOGRAM Study (NCT05124444), 14 chronic active antibody-mediated rejection (CABMR) and 23 stable graft function patients ≥15 years (STA). The selected differentially expressed transcripts between OT and CABMR were used in a validation cohort (n = 396) to predict 3-year kidney allograft loss at 3 time-points using RT-qPCR.

FINDINGS

Archetypal analysis and classifier performance of RNA sequencing data showed that OT is clearly distinguishable from CABMR, but similar to STA. Based on significant transcripts from the validation cohort in univariable analysis, 2 multivariable Cox models were created. A 3-transcript (ADGRG3, ATG2A, and GNLY) model from POD 7 predicted graft loss with C-statistics (C) 0.727 (95% CI, 0.638-0.820). Another 3-transcript (IGHM, CD5, GNLY) model from M3 predicted graft loss with C 0.786 (95% CI, 0.785-0.865). Combining 3-transcripts models with eGFR at POD 7 and M3 improved C-statistics to 0.860 (95% CI, 0.778-0.944) and 0.868 (95% CI, 0.790-0.944), respectively.

INTERPRETATION

Identification of transcripts distinguishing OT from CABMR allowed us to construct models predicting premature graft loss. Identified transcripts reflect mechanisms of injury/repair and alloimmune response when assessed at day 7 or with a loss of protective phenotype when assessed at month 3.

FUNDING

Supported by the Ministry of Health of the Czech Republic under grant NV19-06-00031.

Altered Signatures of Plasma Inflammatory Proteins and Phonotypic Markers of NK Cells in Kidney Transplant Patients upon CMV Reactivation

Cytomegalovirus (CMV) reactivation remains a common opportunistic infection with a prominent role in immune reconstitution in organ transplant recipients. CMVs as important drivers of natural killer (NK) cell differentiation has been indicated to prompt several phenotypic and functional alteration in these cells. We aimed to monitor the reconstitution of NK cells and change the signature of inflammatory proteins at the critical phase of CMV reactivation over six months after kidney transplantation. The present study indicated that CMV reactivation is associated with the development of IL-6, IL-10, and cytotoxic granules, including granzyme-B and granulysin, and the drop in the frequency of CD16 + NKG2A-CD57 + NK cell subset in kidney transplant recipients (KTRs) with reactivation versus non- reactivated ones. Our findings describe distinct immune signatures that emerged with CMV reactivation after kidney transplantation, which may be helpful in the timely management of CMV infection in KTRs.

Characterization of NKG2-A/-C, Kir and CD57 on NK Cells Stimulated with pp65 and IE-1 Antigens in Patients Awaiting Lung Transplant

Introduction: Cytomegalovirus (CMV) is the leading opportunistic infection in lung transplant (LTx) recipients. CMV is associated with graft failure and decreased survival. Recently, new antiviral therapies have been proposed. The present study aimed to investigate NK and T cell subsets of patients awaiting LTx. We analyzed the cellular populations between reactive and non-reactive QuantiFERON (QF) CMV patients for the prediction of immunological response to infection. Methods: Seventeen pre-LTx patients and 15 healthy controls (HC) have been enrolled. QF and IFN-γ ELISA assay detections were applied. NK cell subsets and T cell and proliferation assay were detected before and after stimulation with pp-65 and IE-1 CMV antigens after stratification as QF+ and QF−. Furthermore, we quantified the serum concentrations of NK− and T-related cytokines by bead-based multiplex analysis. Results: CD56^brCD16^lowNKG2A⁺KIR⁺ resulted in the best discriminatory cellular subsets between pre-LTx and HC. Discrepancies emerged between serology and QF assay. Better proliferative capability emerged from patients who were QF+, in particular in CD8 and CD25-activated cells. CD56^brCD16^low, adaptive/memory-like NK and CD8Teff were highly increased only in QF+ patients. Conclusions: QF more than serology is useful in the detection of patients able to respond to viral infection. This study provides new insights in terms of immunological responses to CMV in pre-LTX patients, particularly in NK and T cells biology.

Molecular Diversity of Clinically Stable Human Kidney Allografts

IMPORTANCE

Clinical decision and immunosuppression dosing in kidney transplantation rely on transplant biopsy tissue histology even though histology has low specificity, sensitivity, and reproducibility for rejection diagnosis. The inclusion of stable allografts in mechanistic and clinical studies is vital to provide a normal, noninjured comparative group for all interrogative studies on understanding allograft injury.

OBJECTIVE

To refine the definition of a stable allograft as one that is clinically, histologically, and molecularly quiescent using publicly available transcriptomics data.

DESIGN, SETTING, AND PARTICIPANTS

In this prognostic study, the National Center for Biotechnology Information Gene Expression Omnibus was used to search for microarray gene expression data from kidney transplant tissues, resulting in 38 studies from January 1, 2017, to December 31, 2018. The diagnostic annotations included 510 acute rejection (AR) samples, 1154 histologically stable (hSTA) samples, and 609 normal samples. Raw fluorescence intensity data were downloaded and preprocessed followed by data set merging and batch correction.

MAIN OUTCOMES AND MEASURES

The primary measure was area under the receiver operating characteristics curve from a set of feature selected genes and cell types for distinguishing AR from normal kidney tissue.

RESULTS

Within the 28 data sets, the feature selection procedure identified a set of 6 genes (KLF4, CENPJ, KLF2, PPP1R15A, FOSB, TNFAIP3) (area under the curve [AUC], 0.98) and 5 immune cell types (CD4+ T-cell central memory [Tcm], CD4+ T-cell effector memory [Tem], CD8+ Tem, natural killer [NK] cells, and Type 1 T helper [TH1] cells) (AUC, 0.92) that were combined into 1 composite Instability Score (InstaScore) (AUC, 0.99). The InstaScore was applied to the hSTA samples: 626 of 1154 (54%) were found to be immune quiescent and redefined as histologically and molecularly stable (hSTA/mSTA); 528 of 1154 (46%) were found to have molecular evidence of rejection (hSTA/mAR) and should not have been classified as stable allografts. The validation on an independent cohort of 6 months of protocol biopsy samples in December 2019 showed that hSTA/mAR samples had a significant change in graft function (r = 0.52, P < .001) and graft loss at 5-year follow-up (r = 0.17). A drop by 10 mL/min/1.73m2 in estimated glomerular filtration rate was estimated as a threshold in allograft transitioning from hSTA/mSTA to hSTA/mAR.

CONCLUSIONS AND RELEVANCE

The results of this prognostic study suggest that the InstaScore could provide an important adjunct for comprehensive and highly quantitative phenotyping of protocol kidney transplant biopsy samples and could be integrated into clinical care for accurate estimation of subsequent patient clinical outcomes.

The Yin and Yang of Alarmins in Regulation of Acute Kidney Injury

Acute kidney injury (AKI) is a major clinical burden affecting 20 to 50% of hospitalized and intensive care patients. Irrespective of the initiating factors, the immune system plays a major role in amplifying the disease pathogenesis with certain immune cells contributing to renal damage, whereas others offer protection and facilitate recovery. Alarmins are small molecules and proteins that include granulysins, high-mobility group box 1 protein, interleukin (IL)-1α, IL-16, IL-33, heat shock proteins, the Ca++ binding S100 proteins, adenosine triphosphate, and uric acid. Alarmins are mostly intracellular molecules, and their release to the extracellular milieu signals cellular stress or damage, generally leading to the recruitment of the cells of the immune system. Early studies indicated a pro-inflammatory role for the alarmins by contributing to immune-system dysregulation and worsening of AKI. However, recent developments demonstrate anti-inflammatory mechanisms of certain alarmins or alarmin-sensing receptors, which may participate in the prevention, resolution, and repair of AKI. This dual function of alarmins is intriguing and has confounded the role of alarmins in AKI. In this study, we review the contribution of various alarmins to the pathogenesis of AKI in experimental and clinical studies. We also analyze the approaches for the therapeutic utilization of alarmins for AKI.

The number and cytotoxicity and the expression of cytotoxicity-related molecules in peripheral natural killer (NK) cells do not predict the repeated implantation failure (RIF) for the in vitro fertilization patients

Natural killer (NK) cells are thought to play a key role in the successful establishment of a pregnancy by facilitating immunological adaptation of the semi-allogeneic developing embryo. The aim of this study was to explore the cell number, immunophenotypic characteristics, and activities of peripheral blood NK cells in women with repeated implantation failure (RIF). Peripheral blood was obtained from 27 women with RIF and 11 healthy, fertile controls during the middle luteal phase of the menstrual cycle. CD3^- CD56⁺ NK cells were quantified and analyzed by flow cytometry for the expression of cytolytic molecules (granzyme B, granulysin, and perforin) as well as cell surface receptors responsible for NK cell activation or inhibition (NKG2D, NKp30, NKp46, CD158a, CD158b). NK cytotoxicity was measured at three effector-to-target cell ratios. Women with RIF and fertile controls did not differ significantly in the percentage of circulating CD3⁻CD56⁺ NK cells, or in the proportions of these cells that expressed granzyme B, granulysin, or perforin. The two groups also did not differ significantly in the proportions of NK cells expressing the receptors NKG2D, NKp30, NKp46, CD158a or CD158b. General linear model analysis showed that NK cytotoxicity increased with effector-to-target cell ratio. However, NK cytotoxicity did not differ significantly between patients with RIF and fertile controls. These results suggest that RIF is not associated with significant alterations in the number or function of peripheral blood NK cells.

Donor Genotype and Intragraft Expression of CYP3A5 Reflect the Response to Steroid Treatment During Acute Renal Allograft Rejection

BACKGROUND

Glucocorticoid (GC)-refractory acute rejection (AR) is a risk factor for inferior renal allograft outcome. We investigated genetic predisposition to the response to steroid treatment of acute allograft rejection.

METHODS

Single nucleotide polymorphisms of genes involved in GC signaling (GR, GLCCI1) and drug metabolism and transport (CYP3A5, ABCB1, and PXR) were analyzed in kidney transplant recipients (1995-2005, Leiden cohort, n = 153) treated with methylprednisolone. Significant associations were verified in a second cohort (Berlin cohort, n = 66).

RESULTS

Patients who received a CYP3A5*1 allele expressing allograft had a lower risk of resistance to methylprednisolone during AR (odds ratio, 0.29; 95% confidence interval, 0.11-0.79; P = 0.016 in combined cohorts analysis). No differences were observed for GC signaling or other drug metabolism/transport-related genes. Both before transplantation (n = 69) and at time of AR (n = 88), tissue CYP3A5 mRNA expression was significantly higher in CYP3A5*1 allele expressing donor kidneys than in CYP3A5*3/*3 allografts (P < 0.00001). Moreover, steroid-responsive patients (n = 64) expressed significantly higher intragraft CYP3A5 mRNA levels compared to steroid-refractory patients (n = 42) in AR (P = 0.006).

CONCLUSIONS

CYP3A5 protein expression was detected in tubular epithelial cells and inflammatory cells within the grafts. Our findings show that steroid resistance during AR is associated with donor genotype and intragraft expression levels of CYP3A5.

Transplantomics: Toward Precision Medicine in Transplantation Research

Precision medicine is an emerging integrative approach for disease prevention, early detection, and treatment which takes into account individual variability in genetic and other molecular measurements, medical history, environmental exposures, and lifestyle. The development and availability of genomic and other molecular profiling technologies provide an unprecedented opportunity to apply precision medicine strategies in transplantation research. Developing integrative computational methods to analyze these diverse types of data provides new opportunities to impact diagnostics and therapeutics. In this article, we discuss ways we can leverage molecular data sets to develop new hypotheses for disease mechanisms, identify new disease biomarkers, and reposition drugs for diseases with unmet needs. We specifically discuss computational methods that can be applied to achieve these goals in the context of organ transplant.

Histopathological analysis of infiltrating T cell subsets in acute T cell-mediated rejection in the kidney transplant

AIM

To compare the differential immune T cell subset composition in patients with acute T cell-mediated rejection in the kidney transplant with subset composition in the absence of rejection, and to explore the association of their respective immune profiles with kidney transplant outcomes.

METHODS

A pilot cross-sectional histopathological analysis of the immune infiltrate was performed using immunohistochemistry in a cohort of 14 patients with acute T cell-mediated rejection in the kidney transplant and 7 kidney transplant patients with no rejection subjected to biopsy to investigate acute kidney transplant dysfunction. All patients were recruited consecutively from 2012 to 2014 at the Singapore General Hospital. Association of the immune infiltrates with kidney transplant outcomes at up to 54 mo of follow up was also explored prospectively.

RESULTS

In comparison to the absence of rejection, acute T cell-mediated rejection in the kidney transplant was characterised by numerical dominance of cytotoxic T lymphocytes over Foxp3⁺ regulatory T cells, but did not reach statistical significance owing to the small sample size in our pilot study. There was no obvious difference in absolute numbers of infiltrating cytotoxic T lymphocytes, Foxp3⁺ regulatory T cells and Th17 cells between the two patient groups when quantified separately. Our exploratory analysis on associations of T cell subset quantifications with kidney transplant outcomes revealed that the degree of Th17 cell infiltration was significantly associated with shorter time to doubling of creatinine and shorter time to transplant loss.

CONCLUSION

Although this was a small pilot study, results support our suspicion that in kidney transplant patients the immune balance in acute T cell-mediated rejection is tilted towards the pro-rejection forces and prompt larger and more sophisticated studies.

Cyclosporine Use in Epidermal Necrolysis Is Associated with an Important Mortality Reduction: Evidence from Three Different Approaches

Several immunomodulatory agents are used in the treatment of epidermal necrolysis, but evidence of their efficacy is limited. The Autonomous Community of Madrid has two reference burn units to which all patients with epidermal necrolysis are referred. One burn unit has mostly used cyclosporine (CsA), and the other has used non-CsA therapies (mainly high-dose intravenous immunoglobulin). The allocation of patients to one or the other burn unit was mainly based on proximity, resembling a random assignment. Thus, we took advantage of this "natural experiment" to estimate the mortality risk ratio (MRR) of CsA (n = 26) compared with non-CsA (n = 16) treatment using hospital as an instrumental variable over the period from 2001 to 2015. We also computed the observed versus expected (O/E) MRR in a case series of 49 CsA-treated patients (including 23 patients from other regions treated in Madrid), and using the Score for Toxic Epidermal Necrolysis (i.e., SCORTEN) scale to estimate the expected values. The instrumental variable-based MRR of CsA versus non-CsA was 0.09 (95% confidence interval = 0.00-0.49). The O/E analysis also showed a reduction in mortality risk (MRR_OE = 0.42; 95% confidence interval = 0.14-0.99). We identified five other case series of CsA-treated patients providing MRR_OE and meta-analyzed their results. The pooled MRR_OE (including from this study) was 0.41 (95% confidence interval = 0.21-0.80). All three approaches consistently show that CsA reduces the mortality in epidermal necrolysis patients.

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.

Antimicrobial Properties of an Immunomodulator - 15 kDa Human Granulysin

Granulysin, a cationic protein expressed by human natural killer cells and cytotoxic T lymphocytes, is a mediator for drug-induced Stevens-Johnson syndrome and graft-versus-host disease. Some 15 kDa granulysin are processed into 9 kDa forms and sequestered in cytolytic granules, while others are constitutively secreted into body fluids. Both 9 and 15 kDa granulysin have been shown to be a serum marker for cell-mediated immunity. Furthermore, 15 kDa is able to activate monocyte differentiation. However, its antimicrobial properties have not been clearly addressed. Here, we report a novel method to prepare both the soluble 9 and 15 kDa granulysin and show that the 15 kDa form is more effective than the 9 kDa form in exerting specific antimicrobial activity against Pseudomonas aeruginosa within a range of few micromolars. We also show that the 15 kDa granulysin is able to hyperpolarize the membrane potential and increase membrane permeability of treated bacteria. Interestingly, the bactericidal activity and membrane permeability of the granulysins were markedly reduced at lower pH (pH 5.4) as a result of probable increase in hydrophobicity of the granulysins. Additionally, we’ve also shown the granulysin to inhibit biofilm formation by P. aeruginosa. These results suggest that the 15 kDa granulysin exhibits a novel mechanism in bacteria killing in a way that’s different from most antimicrobial peptides. Our novel granulysin preparation methodology will be useful for further study of action mechanisms of other antimicrobial, cytotoxic and immunomodulating properties in granulysin-mediated diseases.

Granulysin and its clinical significance as a biomarker of immune response and NK cell related neoplasms

Granulysin is a cytotoxic granular protein that was identified from human T cells by using the gene subtraction method in 1987. Based on its amino acid homology, granulysin belongs to the saposin-like protein family. The bioactive 9-kDa form of granulysin is processed from the 15-kDa pro-product in the cytoplasmic granules. It is expressed in CD8-positive αβT cells 5 d after mitogenic stimulation and constitutively in natural killer (NK) cells and γδT cells, although regulation of its expression has not yet been precisely determined. The 9-kDa granulysin form has anti-microbial activity against microorganisms such as bacteria, fungi, mycobacteria and parasites, as well as tumoricidal activity against some tumors at 1-10 μmol/L concentrations. Granulysin is secreted in both Ca-dependent and -independent manners. In sera, only the 15-kDa form is detectable and is expected to be a biomarker for immune potency, acute viral infection, anti-tumor immune reaction, acute graft vs host disease, and NK cell associated neoplasm.

Genes related to antiviral activity, cell migration, and lysis are differentially expressed in CD4(+) T cells in human t cell leukemia virus type 1-associated myelopathy/tropical spastic paraparesis patients

Human T cell leukemia virus type 1 (HTLV-1) preferentially infects CD4(+) T cells and these cells play a central role in HTLV-1 infection. In this study, we investigated the global gene expression profile of circulating CD4(+) T cells from the distinct clinical status of HTLV-1-infected individuals in regard to TAX expression levels. CD4(+) T cells were isolated from asymptomatic HTLV-1 carrier (HAC) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients in order to identify genes involved in HAM/TSP development using a microarray technique. Hierarchical clustering analysis showed that healthy control (CT) and HTLV-1-infected samples clustered separately. We also observed that the HAC and HAM/TSP groups clustered separately regardless of TAX expression. The gene expression profile of CD4(+) T cells was compared among the CT, HAC, and HAM/TSP groups. The paxillin (Pxn), chemokine (C-X-C motif ) receptor 4 (Cxcr4), interleukin 27 (IL27), and granzyme A (Gzma) genes were differentially expressed between the HAC and HAM/TSP groups, regardless of TAX expression. The perforin 1 (Prf1) and forkhead box P3 (Foxp3) genes were increased in the HAM/TSP group and presented a positive correlation to the expression of TAX and the proviral load (PVL). The frequency of CD4(+)FOXP3(+) regulatory T cells (Treg) was higher in HTLV-1-infected individuals. Foxp3 gene expression was positively correlated with cell lysis-related genes (Gzma, Gzmb, and Prf1). These findings suggest that CD4(+) T cell activity is distinct between the HAC and HAM/TSP groups.

Increased metallothionein expression reflects steroid resistance in renal allograft recipients

Steroid-refractory acute rejection is a risk factor for inferior renal allograft outcome. We aimed to gain insight into the mechanisms underlying steroid resistance by identifying novel molecular markers of steroid-refractory acute rejection. Eighty-three kidney transplant recipients (1995-2005), who were treated with methylprednisolone during a first acute rejection episode, were included in this study. Gene expression patterns were investigated in a discovery cohort of 36 acute rejection biopsies, and verified in a validation cohort of 47 acute rejection biopsies. In the discovery set, expression of metallothioneins (MT) was significantly (p < 0.000001) associated with decreased response to steroid treatment. Multivariate analysis resulted in a predictive model containing MT-1 as an independent covariate (AUC = 0.88, p < 0.0000001). In the validation set, MT-1 expression was also significantly associated with steroid resistance (p = 0.029). Metallothionein expression was detected in macrophages and tubular epithelial cells. Parallel to the findings in patients, in vitro experiments of peripheral blood mononuclear cells from 11 donors showed that nonresponse to methylprednisolone treatment is related to highly elevated MT levels. High expression of metallothioneins in renal allografts is associated with resistance to steroid treatment. Metallothioneins regulate intracellular concentrations of zinc, through which they may diminish the zinc-requiring anti-inflammatory effect of the glucocorticoid receptor.

A new nucleic acid-based agent inhibits cytotoxic T lymphocyte-mediated immune disorders

BACKGROUND

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and graft-versus-host disease (GVHD) are distinct immune reactions elicited by drugs or allogeneic antigens; however, they share a pathomechanism with the activation of cytotoxic T lymphocytes (CTLs). CTLs produce cytotoxic proteins, cytokines, chemokines, or immune alarmins, such as granulysin (GNLY), leading to the extensive tissue damage and systemic inflammation seen in patients with SJS/TEN or GVHD. Currently, there is no effective therapeutic agent specific for CTL-mediated immune disorders.

OBJECTIVES

By targeting GNLY(+) CTLs, we aimed to develop a nucleic acid-based agent consisting of an anti-CD8 aptamer with GNLY small interfering RNA (siRNA).

METHODS

We performed systematic evolution of ligands using exponential enrichment to select and identify effective anti-CD8 aptamers. We developed an aptamer-siRNA chimera using a "sticky bridge" method by conjugating the aptamer with siRNA. We analyzed the inhibitory effects of the aptamer-siRNA chimera on CTL responses in patients with SJS/TEN or GVHD.

RESULTS

We identified a novel DNA aptamer (CD8AP17s) targeting CTLs. This aptamer could be specifically internalized into human CTLs. We generated the CD8AP17s aptamer-GNLY siRNA chimera, which showed a greater than 79% inhibitory effect on the production of GNLY by drug/alloantigen-activated T cells. The CD8AP17s aptamer-GNLY siRNA chimera decreased cytotoxicity in in vitro models of both SJS/TEN (elicited by drug-specific antigen) and GVHD (elicited by allogeneic antigens).

CONCLUSIONS

Our results identified a new nucleic acid-based agent (CD8 aptamer-GNLY siRNA chimera) that can significantly inhibit CTL-mediated drug hypersensitivity, such as that seen in patients with SJS/TEN, as well as the alloreactivity seen in patients with GVHD. This study provides a novel therapeutic strategy for CTL-mediated immune disorders.

Quantitative polymerase chain reaction profiling of immunomarkers in rejecting kidney allografts for predicting response to steroid treatment

BACKGROUND

Steroid-resistant acute rejection is a risk factor for inferior renal allograft outcome.

METHODS

From 873 kidney transplant recipients (1995-2005), 108 patients with a first rejection episode were selected for study using strict inclusion criteria and clinical endpoint definition. We aimed to predict response to corticosteroid treatment using gene expression of 65 transcripts. These reflect cytokines, chemokines, and surface and activation markers of various cell types including T cells, macrophages, B cells, and granulocytes. Steroid resistance (40% of the patients) was defined as requirement for antithymocyte globulin treatment within 2 weeks after corticosteroid treatment.

RESULTS

None of the clinical and histomorphologic parameters showed a significant association with response to treatment. Univariate logistic regression analysis resulted in 11 messenger RNA markers, including T-cell-related transcripts CD25, lymphocyte activation gene-3, Granzyme B, and interleukin-10, and macrophage-specific transcripts mannose receptor and S100 calcium-binding protein A9, which significantly discriminated steroid resistant from steroid-responsive rejections (P<0.05). In multivariate logistic regression, the combination of T-cell activation markers CD25:CD3e ratio (odds ratio, 8.7; confidence interval, 2.4-31.2) and lymphocyte activation gene-3 (odds ratio, 3.3; confidence interval, 1.4-7.7) represented the best predictive model for steroid response (P<0.0001). Specificity and sensitivity were 78% and 60%, respectively. After internal stratified 10-fold cross-validation, the model remained significant. Inclusion of clinical variables into the model with molecular variables did not enhance prediction.

CONCLUSIONS

Differences in intragraft expression profiles reflect variability in the response to antirejection treatment. In acute rejection, molecular markers, particularly those reflecting T-cell activation, offer superior prognostic value compared with conventional parameters.

Elevated serum granulysin and its clinical relevance in mature NK-cell neoplasms

Mature natural killer (NK)-cell neoplasms include extranodal NK/T cell lymphoma, nasal type (ENKL), aggressive NK-cell leukemia (ANKL) and chronic lymphoproliferative disorders of NK cells (CLPD-NK). Granulysin, a cytolytic granule protein, is expressed in cytotoxic T cells and NK cells, and is found in the sera as well, and functions as a cytotoxic and proinflammatory protein. Cytolytic proteins, such as granzyme B and perforin, have been shown to play crucial pathophysiological roles in NK/T cell neoplasms and have also been utilized for diagnostic purposes. Granulysin in NK-cell proliferative disorders, however, has yet to be fully analyzed. To elucidate the clinical relevance of granulysin in mature NK-cell neoplasms, we measured serum granulysin and analyzed cytolytic molecules immunohistologically. The median concentrations of serum granulysin were 39.0, 2.85, 2.8 and 1.35 ng/ml in ANKL, ENKL, CLPD-NK and healthy subjects, respectively (P < 0.01). Serum granulysin was significantly elevated in patients with ANKL compared with the levels in ENKL (P = 0.006) and CLPD-NK (P = 0.037). Furthermore, serum granulysin was correlated with whole-blood EBV viral load in ENKL and ANKL (P = 0.005) and was significantly reduced after treatment. Different expression patterns of cytolytic granule proteins were observed among the mature NK-cell neoplasms. Granulysin is closely associated with the characteristics of NK-cell neoplasms and serum granulysin may serve as a novel biomarker for these disorders.

Evaluation of vascular lesions using circulating endothelial cells in renal transplant patients

Objective: To investigate the correlation between circulating endothelial cells (CECs) and vascular lesions in renal allografts.

Methodology: Sixty-two renal transplant patients were divided into four groups according to biopsy data. CECs were isolated from peripheral blood with anti-CD136-coated immunomagnetic Dynabeads and counted by microscopy during biopsy. CEC numbers were compared in each group, as well as the correlation between CECs and C4d and vascular changes in different groups.

Result: CECs counts were higher in the acute rejection (AR) with endarteritis group than in the normal group (p < 0.01), acute tubular necrosis (ATN) group (p < 0.01) and chronic allograft nephropathy (CAN) group (p < 0.01), there were no difference among ATN, normal and CAN) group (p = 0.587). There was no difference among the normal group without hyaline, normal group with hyaline and CAN with hyaline group. An increasing CECs count was related to C4d-positive AR (p = 0.008; κ score = 0.519) and infiltration of inflammatory cells (p = 0.002, κ score = 0.573) in proximal tubule cells (PTCs). The CECs count decreased after intensive therapy in five patients (p = 0.001).

Conclusion: Elevation of the CEC count in blood was related to endarteritis. Elevation of CEC count was related to C4d deposition and infiltration of inflammatory cells in PTCs.

Increased prevalence of peripheral blood granulysin-producing cytotoxic T lymphocytes in preeclampsia

Preeclampsia (PE) is a severe complication of pregnancy characterized by an excessive maternal systemic inflammatory response with activation of both the innate and adaptive arms of the immune system. Granulysin is a cytolytic and pro-inflammatory molecule expressed by activated human cytotoxic T lymphocytes and natural killer (NK) cells. Recent data show that serum granulysin levels are elevated in preeclampsia. The purpose of this study was to determine whether the proportion of peripheral blood cytotoxic T lymphocytes and NK cells that express intracellular granulysin is altered in PE. Twenty-two preeclamptic patients and 29 healthy pregnant women were involved in this case-control study. Intracellular granulysin expression of lymphocytes was determined with flow cytometric examination. In healthy pregnant women, the majority of NK cells and a small fraction of cytotoxic T cells expressed granulysin in their cytoplasma (median (25-75 percentile): 53.5 (45.6-68.0)% and 13.8 (8.5-23.1)%, respectively). In PE, the percentage of granulysin-positive cytotoxic T lymphocytes was markedly increased, while the proportion of granulysin-producing NK cells was unchanged as compared to healthy pregnant women (for cytotoxic T cells: 34.1 (19.3-45.6)%, p<0.001; for NK cells: 57.2 (42.9-74.9)%, p>0.05). Maternal age of healthy pregnant women showed a significant inverse correlation with the frequency of granulysin-expressing NK cells (Spearman R=-0.44, p<0.05), while their BMI correlated positively with the proportions of granulysin-positive cytotoxic T cells and NK cells (Spearman R=0.43, p<0.05 for both). In conclusion, the majority of circulating NK cells but only a small population of cytotoxic T cells shows intracellular granulysin expression in normal pregnancy. In preeclampsia, the proportion of granulysin-producing cytotoxic T cells in the peripheral blood is markedly increased, which might contribute to the development of the pro-inflammatory Th1-type immune responses characteristics of the maternal syndrome of the disease.

Biomarkers in solid organ transplantation: establishing personalized transplantation medicine

Technological advances in molecular and in silico research have enabled significant progress towards personalized transplantation medicine. It is now possible to conduct comprehensive biomarker development studies of transplant organ pathologies, correlating genomic, transcriptomic and proteomic information from donor and recipient with clinical and histological phenotypes. Translation of these advances to the clinical setting will allow assessment of an individual patient's risk of allograft damage or accommodation. Transplantation biomarkers are needed for active monitoring of immunosuppression, to reduce patient morbidity, and to improve long-term allograft function and life expectancy. Here, we highlight recent pre- and post-transplantation biomarkers of acute and chronic allograft damage or adaptation, focusing on peripheral blood-based methodologies for non-invasive application. We then critically discuss current findings with respect to their future application in routine clinical transplantation medicine. Complement-system-associated SNPs present potential biomarkers that may be used to indicate the baseline risk for allograft damage prior to transplantation. The detection of antibodies against novel, non-HLA, MICA antigens, and the expression of cytokine genes and proteins and cytotoxicity-related genes have been correlated with allograft damage and are potential post-transplantation biomarkers indicating allograft damage at the molecular level, although these do not have clinical relevance yet. Several multi-gene expression-based biomarker panels have been identified that accurately predicted graft accommodation in liver transplant recipients and may be developed into a predictive biomarker assay.

Protein expression profile of human renal mesangial cells under high glucose

BACKGROUND

To understand the spectrum of proteins affected by diabetic nephropathy and to characterize the molecular functions and biological processes they control, the protein expression profile of human renal mesangial cells (HMCs) under high glucose was analyzed.

METHODS

HMCs were divided into a high glucose-cultured group (30 mmol/l) and a normal glucose-cultured group (5 mmol/l). The total proteins of the two groups were separated and analyzed by two-dimensional difference gel electrophoresis (DIGE). Spots that were differentially expressed were picked and digested with trypsin and subjected to MALDI-TOF MS for protein identification.

RESULTS

147 protein spots whose expression levels were significantly increased or decreased more than 1.5-fold in HMCs under high glucose culture were identified. 32 proteins were identified by peptide mass fingerprinting. The protein spots of phosphatidylethanolamine-binding protein 1, granulysin, ATP synthase, H(+) transporter, mitochondrial F0 complex and subunit F2 were observed only in the high glucose group. The expression of 24 proteins was upregulated by high glucose, including eosinophil cationic protein and others. The expression of 5 proteins was downregulated by high glucose, including proteasome β6 subunit precursor, among others.

CONCLUSION

32 protein expressions of human glomerular mesangial cells were regulated by high glucose. In-depth analysis of these differentially expressed proteins' function and crosstalk is expected to provide an experimental basis for clarifying the pathogenesis of diabetic nephropathy.

Perforin: more than just a pore-forming protein

Cellular apoptosis induced by T cells is mainly mediated by two pathways. One, granule exocytosis utilizes perforin/granzymes. The other involves signaling through death receptors of the TNF-alpha R super-family, especially FasL. Perforin plays a central role in apoptosis induced by granzymes. However, the mechanisms of perforin-mediated cytotoxicity are still not elucidated completely. Perforin is not only a pore-forming protein, but also performs multiple biological functions or perforin performs one biological function (cytolysis), but has multiple biological implications in the cellular immune responses, including regulation of proliferation of CD8+ CTLs.

HLA class I (ABC) upregulation on peripheral blood CD3+/CD8+ T lymphocyte surface is a potential predictor of acute rejection in renal transplantation

BACKGROUND

Renal transplantation is currently the prevalent therapy for most patients with end-stage renal disease. No clinical markers for such rejection have been universally accepted. We aimed to investigate the possibility of use of human leukocyte antigen (HLA) class I (ABC) on peripheral blood CD3+/CD8+ T lymphocytes as a marker of acute rejection.

METHODS

For recipients undergoing renal transplantation from September 2007 to November 2008, peripheral blood samples were obtained pretransplantation and at days 3 and 7 posttransplantation when the patients were still hospitalized and at weeks 2 and 3 and months 1, 2, 3, and 6 posttransplantation. For patients with fever, lumbodynia, gross hematuria, or oliguria after transplantation, blood samples were collected immediately before and at days 3 and 7 after the administration of anti-inflammatory regents. The level of HLA class I (ABC) on peripheral-blood CD3+/CD8+ T lymphocytes was measured on flow cytometry.

RESULTS

For the 79 transplant recipients, the level of HLA class I (ABC) on peripheral-blood CD3+/CD8+ T lymphocytes was consistently elevated during the first 3 weeks after transplantation, declined gradually to pretransplantation levels, then tapered off and remained stable. Patients experiencing acute rejection (AR) or not after transplantation did not differ in level of HLA class I (ABC) up to 6-month follow-up, except at days 14 and 21 after transplantation, when the level was higher for patients experiencing AR (P<0.01).

CONCLUSIONS

Upregulation of HLA class I (ABC) on peripheral-blood CD3+/CD8+ T lymphocytes could be used as an accurate and reliable predictor of AR after renal transplantation.

Biology and clinical relevance of granulysin

Granulysin is a cytolytic and proinflammatory molecule first identified by a screen for genes expressed 'late' (3-5 days) after activation of human peripheral blood mononuclear cells. Granulysin is present in cytolytic granules of cytotoxic T lymphocytes and natural killer cells. Granulysin is made in a 15-kDa form that is cleaved into a 9-kDa form at both the amino and the carboxy termini. The 15-kDa form is constitutively secreted, and its function remains poorly understood. The 9-kDa form is released by receptor-mediated granule exocytosis. Nine kiloDalton granulysin is broadly cytolytic against tumors and microbes, including gram-positive and gram-negative bacteria, fungi/yeast and parasites. It kills the causative agents of both tuberculosis and malaria. Granulysin is also a chemoattractant for T lymphocytes, monocytes and other inflammatory cells and activates the expression of a number of cytokines, including regulated upon activation T cell expressed and secreted (RANTES), monocyte chemoattractant protein (MCP)-1, MCP-3, macrophage inflammatory protein (MIP)-1 alpha, interleukin (IL)-10, IL-1, IL-6 and interferon (IFN)-alpha. Granulysin is implicated in a myriad of diseases including infection, cancer, transplantation, autoimmunity, skin and reproductive maladies. Small synthetic forms of granulysin are being developed as novel antibiotics. Studies of the full-length forms may give rise to new diagnostics and therapeutics for use in a wide variety of diseases.

Microarrays: monitoring for transplant tolerance and mechanistic insights

With recent advances in immunology and a growing understanding of transplantation biology, the development of reliable assays that may be used for identification and prediction of the current state of an immune response (rejection and tolerance) are urgently needed to allow us to predict the development of immunologic graft injury, individualize immunosuppression, rationally minimize immunosuppressive drug toxicity, promote a better understanding of the mechanisms underlying stable graft acceptance, and aid in the design of tolerance-inducing clinical transplantation trials. Microarrays can provide nonbiased, simultaneous global expression patterns for more than 40,000 human genes across different experiments. High throughput microarray technology offers a means to study disease-specific transcriptional changes in tissue biopsy, peripheral blood, and biofluids.

Immunosuppressive drug-free operational immune tolerance in human kidney transplant recipients: Part I. Blood gene expression statistical analysis

Survival of solid organ grafts depends on life-long immunosuppression, which results in increased rates of infection and malignancy. Induction of tolerance to allografts would represent the optimal solution for controlling both chronic rejection (CR) and side effects of immunosuppression. Although spontaneous "operational tolerance" can occur in human kidney transplantation, the lack of noninvasive peripheral blood biological markers of this rare phenomenon precludes the identification of potentially tolerant patients in whom immunosuppression could be tapered as well as the development of new tolerance inducing strategies. Here, the potential of high throughput microarray technology to decipher complex pathologies allowed us to study the peripheral blood specific gene expression profile and corresponding EASE molecular pathways associated to operational tolerance in a cohort of human kidney graft recipients. In comparison with patients with CR, tolerant patients displayed a set of 343 differentially expressed genes, mainly immune and defense genes, in their peripheral blood mononuclear cells (PBMC), of which 223 were also different from healthy volunteers. Using the expression pattern of these 343 genes, we were able to classify correctly >80% of the patients in a cross-validation experiment and classified correctly all of the samples over time. Collectively, this study identifies a unique PBMC gene signature associated with human operational tolerance in kidney transplantation by a classical statistical microarray analysis and, in the second part, by a nonstatistical analysis.

Granulysin produced by uterine natural killer cells induces apoptosis of extravillous trophoblasts in spontaneous abortion

Immune changes are known to occur in recurrent spontaneous abortion, but it is unclear whether either maternal natural killer (NK) cells or T cells attack fetus-derived trophoblasts. To clarify the immunological causes of spontaneous abortion, we examined the relationship between cytotoxic granule proteins in decidual lymphocytes, such as granulysin, granzyme B, and perforin, and the induction of apoptosis in extravillous trophoblasts (EVTs). The number of granulysin-positive CD56(bright) NK cells increased significantly in the decidua basalis during spontaneous abortion compared with normal pregnancy; however, granzyme B- and perforin-positive cells did not change. Interestingly, the expression of granulysin was also detected in the nuclei of EVTs in spontaneous abortion samples. When IL-2-stimulated CD56(bright) NK cells were cocultured with EVT cells (HTR-8/SV40neo), granulysin was found initially in the cytoplasm and then accumulated in the nuclei of the HTR-8/SV40neo cells. Furthermore, transfected cells expressing a GFP-granulysin fusion protein induced apoptosis in HTR-8/SV40neo cells independently of caspases. Our results suggest that granulysin-positive uterine NK cells attack EVTs; subsequently, the uNK-derived granulysin actively accumulates in the nuclei of EVTs, causing the death of EVTs due to apoptosis. These data support a new apoptosis pathway for trophoblasts via uNK-derived granulysin, suggesting that granulysin is involved in spontaneous abortion.

Acute renal allograft rejection is associated with increased levels of vascular endothelial growth factor in the urine

AIM

The purpose of this study was to assess whether measurement of urinary vascular endothelial growth factor (VEGF) could be adopted as a new non-invasive diagnostic tool for acute rejection following renal transplantation.

METHODS

Urinary concentration of VEGF was determined by an enzyme-linked immunosorbent assay technique in 215 renal allograft recipients and 80 healthy controls.

RESULTS

Subjects with acute rejection (n=67) excreted urinary VEGF at a significantly higher level (28.57+/-6.21, 95% CI: 16.18-40.97 pg/mumol creatinine) than those without acute rejection. This included subjects with stable renal function and no abnormal histological findings (n=119), acute tubular necrosis (n=15), chronic allograft nephropathy (n=14) and healthy controls (n=80). Using a urinary VEGF/creatinine ratio of 3.64 pg/micromol as the cut-off point, the sensitivity and specificity for diagnosing acute rejection were 85.1 and 74.8%, respectively (P<0.001). Patients with steroid-resistant acute rejection had significantly greater urinary VEGF concentration than patients with steroid-sensitive acute rejection (42.09+/-10.00 vs 9.74+/-2.63 pg/micromol creatinine, P<0.001). Patients with graft loss after acute rejection had significantly greater urinary VEGF concentration than patients with reversible acute rejection (106.66+/-38.60 vs 19.46+/-4.13 pg/micromol creatinine, P=0.001). Using a urinary VEGF/creatinine ratio of 22.48 pg/micromol as the cut-off point, the sensitivity and specificity of the prediction to graft loss after acute rejection were 85.7% and 78.3%, respectively (P=0.001).

CONCLUSION

This study demonstrates that the monitoring of urinary VEGF may be a useful non-invasive approach for the detection of acute rejection. Additionally, urinary VEGF levels were shown to predict the response to anti-rejection therapy and to predict a poor outcome after acute rejection.

Diagnosis of Acute Renal Allograft Rejection by Analyzing Whole Blood mRNA Expression of Lymphocyte Marker Molecules

BACKGROUND

Currently, the diagnosis of acute rejection after kidney transplantation is based on a kidney biopsy taken after clinical rejection suspicion. A robust, noninvasive diagnostic method would allow easier and more frequent monitoring of the patient and the graft. Potentially, a straightforward method would be the analysis of lymphocyte marker molecule expression from whole blood samples.

METHODS

Whole blood samples were collected prospectively in a single kidney transplantation center from 50 adult kidney recipients transplanted between 2001 and 2005. The mRNA expression of granzyme B, perforin, FasL, granulysin, CD154, ICOS, CTLA4 and PD-1 were analyzed with real-time quantitative polymerase chain reaction.

RESULTS

The expression of ICOS and CD154 were significantly lower in rejection patients than in control patients (P<0.001). Both genes gave statistically significant area under receiver operating characteristic curve (AUC; 0.87, 0.88) with 84% sensitivity and 100% specificity for CD154 and 76% and 86% for ICOS, respectively. In paired rejection and postrejection therapy samples, the expression of both genes significantly increased during rejection therapy (P<0.001). When rejection patients were compared to patients biopsied because of other reasons of graft dysfunction, both CD154 and ICOS were lower in rejection patients but only CD154 was statistically significant (P=0.028, AUC=0.740, sensitivity 52%, specificity 90%). The other studied genes gave no consistent statistically significant results.

CONCLUSIONS

The whole blood gene expression quantities of costimulatory molecules CD154 and ICOS reasonably robustly differentiated rejection patients from control patients. The clinical use of the analysis is limited by poor capability to differentiate patients with rejection from patients with other causes of graft dysfunction.

Plasma granulysin levels and cellular interferon-gamma production correlate with curative host responses in tuberculosis, while plasma interferon-gamma levels correlate with tuberculosis disease activity in adults

Granulysin is a recently identified cytolytic protein which is expressed by human cytotoxic T-lymphocytes and natural killer (NK)-cells, and has broad antimicrobial and tumoricidal activity. Circulating granulysin levels are associated with T- and NK-cell activity, and may thus reflect protection-associated cellular immune responses. In a case-control study in Indonesia, a highly tuberculosis (TB)-endemic country, we therefore determined plasma granulysin levels in adults with active pulmonary TB before, during, and after TB treatment, both in mild/moderate-TB and advanced-TB patients, and compared these to healthy neighbourhood controls. Adults with active pulmonary TB had significantly lower plasma granulysin levels compared to controls. After 2 months of anti-TB therapy, levels in TB patients had significantly increased, reaching values similar to those in controls. Plasma granulysin levels further increased after completion of TB therapy, being significantly higher than those in controls. Plasma granulysin levels correlated inversely with TB disease activity but not with TB disease severity. In contrast, plasma interferon-gamma (IFN-gamma) levels were significantly higher in active TB cases than in controls, normalised during treatment and correlated with both TB disease activity and TB disease severity. At the cellular level, granulysin and IFN-gamma expression both correlated inversely with disease activity. Interestingly, granulysin was predominantly expressed by IFN-gamma negative T-cells, suggesting that the cellular sources of IFN-gamma and granulysin in TB are partly non-overlapping. The observation that plasma granulysin levels and cellular IFN-gamma production correlate with curative host responses in pulmonary tuberculosis points to a potentially important role of granulysin, next to IFN-gamma, in host defence against M. tuberculosis.

Decreased serum granulysin levels in childhood tuberculosis which reverse after therapy

Granulysin is a cytolytic protein of natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). Serum levels of granulysin are related to host cellular immunity. We used an ELISA to quantify granulysin serum levels in children with tuberculosis (TB), before and after chemotherapy. The study involved children affected by different clinical forms of TB (n=72) and healthy control children (n=150) from the same geographical area and of similar socio-economic background. Serum granulysin levels before the initiation of TB therapy were significantly lower in children with TB compared to controls, with the lowest levels being found in TB patients who were PPD skin test negative. No statistically significant differences were found between serum granulysin levels and clinical severity (mild/moderate or advanced pulmonary TB) or the clinical form (pulmonary or extra-pulmonary) of TB. At four months after completion of therapy, serum granulysin levels in children treated for TB were not significantly different to those observed in control children. This finding was paralleled by the increased in vitro mycobactericidal activity of sera from TB patients after completion of therapy. We propose that serum granulysin levels may provide a marker of disease activity in childhood TB and might be useful for monitoring improvement after chemotherapy.

Granulysin-mediated tumor rejection in transgenic mice

Granulysin (GNLY) is a cytolytic molecule expressed by human CTL and NK cells with activity against a variety of tumors and microbes, including Mycobacterium tuberculosis. Although the molecular mechanism of GNLY-induced apoptosis of Jurkat T cells is well defined in vitro, no direct evidence for its in vivo effects has been demonstrated. Because there is no murine homologue of GNLY, we generated mice expressing GNLY using a bacterial artificial chromosome containing the human GNLY gene and its 5' and 3' flanking regions. GNLY is expressed in leukocytes from transgenic mice with similar kinetics as in PBMC from humans: GNLY is constitutively expressed in NK cells and, following stimulation through the TCR, appears in T lymphocytes 8-10 days after activation. Both forms of GNLY (9 and 15 kDa) are produced by activated T cells, whereas the 15-kDa form predominates in freshly isolated NK cells from transgenic animals. GNLY mRNA is highest in spleen, with detectable expression in thymus and lungs, and minimal expression in heart, kidney, liver, muscle, intestine, and brain. Allospecific cell lines generated from GNLY transgenic animals showed enhanced killing of target cells. In vivo effects of GNLY were evaluated using the syngeneic T lymphoma tumor C6VL. GNLY transgenic mice survived significantly longer than nontransgenic littermates in response to a lethal tumor challenge. These findings demonstrate for the first time an in vivo effect of GNLY and suggest that GNLY may prove a useful therapeutic modality for the treatment of cancer.

Heightened expression of the cytotoxicity receptor NKG2D correlates with acute and chronic nephropathy after kidney transplantation

The activating cytotoxicity receptor NKG2D binds to stress-regulated molecules encoded by the major histocompatibility complex class I chain-related (MIC) and UL-16-binding protein (ULBP)/retinoic acid early transcript (RAET) gene family. To assess whether acute allograft rejection leads to an induction of these inducible ligands and their receptor NKG2D, we examined the mRNA profiles in kidney transplant biopsies. Expression levels were correlated with the incidence of acute rejection (aRx) episodes and chronic allograft nephropathy (CAN) proven by histology. Whereas MICA, ULBP1/3 and RAET1-E did not display heightened gene expression, elevated levels of NKG2D mRNA could be associated with aRx (p < 0.001). Immunohistology of kidney biopsies diagnosed with aRx revealed NKG2D+ cells in tubulointerstitial areas positive for CD8+ cells. Most importantly, elevated levels of NKG2D mRNA were associated with restricted long-term graft function assessed by the glomerular filtration rate at 6, 12 and 18 months posttransplantation. Induced NKG2D mRNA expression was still observable in biopsies diagnosed with CAN (p < 0.001), demonstrating a higher sensitivity and specificity compared to CD3, granzyme B and granulysin mRNA measurement. Significant elevated levels of NKG2D mRNA could be further detected in urine sediment prior to aRx, suggesting this receptor as a new candidate marker for the diagnosis of acute and chronic allograft rejection.

Designer genes: Filling the gap in transplantation

Accelerated evolution of the field of functional genomics has been greatly facilitated by high-throughput microarray-based gene function studies, relating to the parallel and serial expression measurements of genomes. Microarray experimentation is being applied for the study of basic research questions, drug target discovery, pharmacology, toxicogenomics, target selectivity, disease biomarker determination, development of prognostic tests, and disease subclass determination. This article will review the current applications of microarray technology in the field of organ transplantation and discuss the potential impact of this technology on transplantation medicine.

Microarrays: a monitoring tool for transplant patients?

Microarray technology holds a distinct advantage over traditional genomic methods, with the unique capability to rapidly generate multiple global gene expression profiles in parallel. This technology is quickly gaining widespread use in many areas of science and medicine because it can be easily adapted to study many experimental questions, particularly relating to disease heterogeneity. Microarray experiments have begun to advance our understanding of the underlying molecular processes in solid organ transplantation; however, several obstacles must be overcome before this technology is ready for application in the clinical setting. This article will review the current applications of microarray technology in the field of transplantation, and discuss the potential impact of this technology on monitoring of solid organ transplant recipients.

Expression of granulysin in polymyositis and inclusion-body myositis

BACKGROUND

Granulysin, a recently defined cytolytic molecule, is expressed in cytotoxic T cells and natural killer cells in a similar way to perforin, which is reported to have a major role in the pathogenesis of polymyositis and inclusion-body myositis (IBM).

OBJECTIVE

To clarify the role of granulysin in polymyositis and IBM.

METHODS

The expression of granulysin and perforin was examined by double staining with CD8, CD4 and CD56 in endomysial infiltrating cells and autoinvasive cells in muscle biopsy specimens of 17 patients with polymyositis (6 steroid resistant and 11 steroid responsive) and of 7 patients with IBM.

RESULTS

Similar to perforin, granulysin was expressed in CD8, CD4 or CD56 cells in patients with polymyositis and IBM. The ratio of cells double positive for granulysin and CD8 to all CD8 cells at endomysial sites was notably higher in steroid-resistant polymyositis than in steroid-responsive polymyositis and IBM.

CONCLUSION

Granulysin expression in CD8 cells seems to be correlated with steroid resistance in polymyositis.

Plasma granulysin concentrations and preeclampsia risk

OBJECTIVE

Epidemiological, clinical and histological data suggest intriguing similarities between preeclampsia and graft-host-rejection. Granulysin, a novel biomarker of overall cellular immunity, is secreted by natural killer cells and cytotoxic T lymphocytes, which are associated with graft-host-rejection. Plasma granulysin was elevated in Japanese preeclamptic women.

DESIGN AND METHODS

50 preeclampsia cases and 50 normotensive controls (USA) were studied. Plasma granulysin at delivery was determined using enzyme immunoassay. Logistic regression procedures were used to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Granulysin were elevated in preeclampsia cases compared with controls (3.01+/-0.18 vs. 2.22+/-0.14 ng/mL, p<0.01). After adjusting for age, body-mass-index and race, women with higher granulysin concentrations (> or =1.89 ng/mL) experienced a 2.9-fold (95%CI 1.1-7.8) increased preeclampsia risk compared with women with lower granulysin (<1.89 ng/mL).

CONCLUSIONS

These data offer further evidence of a predominant Th1 immune status associated with preeclampsia. Prospective studies are needed to determine whether granulysin is elevated early in pregnancy.

Analysis of serum granulysin in patients with hematopoietic stem-cell transplantation: its usefulness as a marker of graft-versus-host reaction

Granulysin is a newly identified CTL/NK cell-related cytotoxic protein, which is secreted in both constitutive and Ca-dependent manner. To evaluate its significance in stem-cell transplantation (SCT), serum granulysin was measured by newly established ELISA method in 26 patients undergoing SCT (21 allogeneic and 5 autologous). In the allogeneic SCT, granulysin was transiently increased in 3 weeks, which was not observed in autologous SCT. In acute GVHD, serum granulysin was markedly increased and correlated with the severity of GVHD. Elevation of granulysin was not necessarily associated with increase of sIL2R or IFN-gamma. In vitro, allospecific T cells released granulysin in an allo-specific manner, and it was correlated with allo-specific cytotoxic activity. These results indicate that increased release of granulysin presents alloreactivity and serum granulysin is useful as a marker of GVHD in SCT.

Chipping into the human genome: novel insights for transplantation

High throughput, high density platforms for transcriptional, proteomic, and metabonomic analyses are opening new doors for improving our understanding of the complexity and redundancy of the immune system in the interplay of the innate and allo-immune responses in organ transplantation. New insights are being obtained into the possible discrepancies between the gold standard of tissue pathological diagnosis and clinical graft outcomes, as new transcriptional categories of transplant rejection evolve. The bystander effects of chronic immunosuppression underlying the complexities of graft dysfunction are beginning to be understood. Non-invasive mechanisms to monitor transplants, by following 'footprints' of biomarker sets that reflect the disease phenotype, are being pursued for their clinical application for direct patient care. Utilization of these same biomarker sets may also offer a unique means to titrate immunosuppression and predict specific graft dysfunction events prior to clinical decline, thus bringing in the potential to reduce patient morbidity from infection and malignancy, preserve graft integrity, and limit the progression of chronic graft injury. Bioinformatics support is integral to the unraveling of the mysteries of the human genome, proteome, and metabolome in disease and in health.