In situ expression of tumor necrosis factor-alpha, interferon-gamma, and interleukin-2 receptors in renal allograft biopsies

TNF-α -308A/G SNP association with kidney allograft rejection in Algerian population: A retrospective case-control study

No consensus has been reached regarding the association beween the -308A/G single nucleotide polymorphism (SNP) in the tumor necrosis factor-α gene (TNFA) and kidney allograft rejection (KAR). Our retrospective case-control study aimed to assess the association of the SNP with KAR in Algerian patients who underwent kidney transplantation. The study enrolled 313 Algerian patients: 58 kidney-transplant recipients without rejection events (PWoR); 58 kidney-transplant recipients with at least one rejection event, with or without graft loss (PWR); and 197 healthy individuals (HI). The TNFA -308A/G SNP was genotyped using a real-time polymerase chain reaction. The results demonstrated that, the frequencies of TNFA -308A allele and AA genotype were higher in the PWR than in the HI groups (p = 0.001, OR = 2.26, CI = 1.33-3.77 and p = 0.0004, OR = 5.53, CI-1.89-16.6, respectively). Furthermore, the frequencies were higher among the PWR than among the PWoR groups (p = 0.001, OR = 3.29, CI = 1.56-7.21 and p = 0.0006, OR = 28.26, CI = 1.62-493.2, respectively), particularly among PWR patients with de novo anti-human leukocyte antigens (HLA) antibodies (PG-a-HLA-Ab). However, the frequency of TNFA -308G allele was lower in the PWR group than in the PWoR group (p = 0.001, OR = 0.3, CI = 0.1-0.64) and the HI group (p = 0.001, OR = 0.44, CI = 0.27-0.44). Our results suggest an association of the TNFA -308A/G alleles with KAR in Algerian patients who underwent kidney transplantation. Carriers of TNFA -308A allele who have PG-a-HLA-Ab might have a higher risk, whereas TNFA -308G allele carriers could have a lower risk of KAR. Thus, therapeutic strategies can be adapted to minimize KAR risk in patients who have a genetic proclivity for increased pro-inflammatory TNF-α activity.

Early postoperative urinary MCP-1 as a potential biomarker predicting acute rejection in living donor kidney transplantation: a prospective cohort study

We investigated the clinical relevance of urinary cytokines/chemokines reflecting intrarenal immunologic micromilieu as prognostic markers and the optimal measurement timing after living donor kidney transplantation (LDKT). This prospective cohort study included 77 LDKT patients who were followed for ≥ 5 years. Patients were divided into control (n = 42) or acute rejection (AR, n = 35) group. Early AR was defined as AR occurring within 3 months. Serum and urine cytokines/chemokines were measured serially as follows: intraoperative, 8/24/72 h, 1 week, 3 months, and 1 year after LDKT. Intrarenal total leukocytes, T cells, and B cells were analyzed with immunohistochemistry followed by tissueFAXS. Urinary MCP-1 and fractalkine were also analyzed in a validation cohort. Urinary MCP-1 after one week was higher in the AR group. Urinary MCP-1, fractalkine, TNF-α, RANTES, and IL-6 after one week were significantly higher in the early AR group. Intrarenal total leukocytes and T cells were elevated in the AR group compared with the control group. Urinary fractalkine, MCP-1, and IL-10 showed positive correlation with intrarenal leukocyte infiltration. Post-KT 1 week urinary MCP-1 showed predictive value in the validation cohort. One-week post-KT urinary MCP-1 may be used as a noninvasive diagnostic marker for predicting AR after LDKT.

Comparison of human adipose stromal vascular fraction and adipose-derived mesenchymal stem cells for the attenuation of acute renal ischemia/reperfusion injury

Stem cells therapy has been suggested as a promising option for the treatment of acute kidney injury (AKI). This study was performed to compare the abilities of xenogenic transplantation of human adipose stromal vascular fraction (SVF) and adipose-derived mesenchymal stem cells (AdMSCs) to facilitate the recovery of renal function and structure in a rat model of ischemia/reperfusion (IR) induced AKI. SVF or AdMSCs were transplanted to the injured kidney through intra-parenchymal injection. Significantly improved renal function and reduced tubular injury were observed in SVF and AdMSCs groups. Administration of SVF or AdMSCs contributed to significantly improved cell proliferation and markedly reduced cell apoptosis in parallel with reduced microvascular rarefaction in injured kidney. IR injury resulted in higher levels of inflammatory cytokines, whereas xenogenic transplantation of SVF or AdMSCs reduced but not induced inflammatory cytokines expression. Additionally, in vitro study showed that administration of SVF or AdMSCs could also significantly promote the proliferation and survival of renal tubular epithelial cells underwent hypoxia/reoxygenation injury through secreting various growth factors. However, cell proliferation was significantly promoted in SVF group than in AdMSCs group. In conclusion, our study demonstrated that administration of SVF or AdMSCs was equally effective in attenuating acute renal IR injury.

Fish oil for kidney transplant recipients

BACKGROUND

Calcineurin inhibitors used in kidney transplantation for immunosuppression have adverse effects that may contribute to nephrotoxicity and increased cardiovascular risk profile. Fish oils are rich in very long chain omega-3 fatty acids, which may reduce nephrotoxicity by improving endothelial function and reduce rejection rates through their immuno-modulatory effects. They may also modify the cardiovascular risk profile. Hence, fish oils may potentially prolong graft survival and reduce cardiovascular mortality.

OBJECTIVES

This review aimed to look at the benefits and harms of fish oil treatment in ameliorating the kidney and cardiovascular adverse effects of CNI-based immunosuppressive therapy in kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register (up to 17 March 2016) through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs of fish oils in kidney transplant recipients on a calcineurin inhibitor-based immunosuppressive regimen. RCTs of fish oil versus statins were included.

DATA COLLECTION AND ANALYSIS

Data was extracted and the quality of studies assessed by two authors, with differences resolved by discussion with a third independent author. Dichotomous outcomes were reported as risk ratio (RR) and continuous outcome measures were reported as the mean difference (MD) with 95% confidence intervals using the random effects model. Heterogeneity was assessed using a Chi(2) test on n-1 degrees of freedom and the I(2) statistic. Data not suitable for pooling were tabulated and described.

MAIN RESULTS

Fifteen studies (733 patients) were suitable for analysis. All studies were small and had variable methodology. Fish oil did not significantly affect patient or graft survival, acute rejection rates, or calcineurin inhibitor toxicity when compared to placebo. Overall SCr was significantly lower in the fish oil group compared to placebo (5 studies, 237 participants: MD -30.63 µmol/L, 95% CI -59.74 to -1.53; I(2) = 88%). In the subgroup analysis, this was only significant in the long-course (six months or more) group (4 studies, 157 participants: MD -37.41 µmol/L, 95% CI -69.89 to -4.94; I(2) = 82%). Fish oil treatment was associated with a lower diastolic blood pressure (4 studies, 200 participants: MD -4.53 mm Hg, 95% CI -7.60 to -1.45) compared to placebo. Patients receiving fish oil for more than six months had a modest increase in HDL (5 studies, 178 participants: MD 0.12 mmol/L, 95% CI 0.03 to 0.21; I(2) = 47%) compared to placebo. Fish oil effects on lipids were not significantly different from low-dose statins. There was insufficient data to analyse cardiovascular outcomes. Fishy aftertaste and gastrointestinal upset were common but did not result in significant patient drop-out.

AUTHORS' CONCLUSIONS

There is insufficient evidence from currently available RCTs to recommend fish oil therapy to improve kidney function, rejection rates, patient survival or graft survival. The improvements in HDL cholesterol and diastolic blood pressure were too modest to recommend routine use. To determine a benefit in clinical outcomes, future RCTs will need to be adequately powered with these outcomes in mind.

Fractalkine-CX3CR1-dependent recruitment and retention of human CD1c+ myeloid dendritic cells by in vitro-activated proximal tubular epithelial cells

Chemokines play pivotal roles in tissue recruitment and retention of leukocytes, with CX3CR1 recently identified as a chemokine receptor that selectively targets mouse kidney dendritic cells (DCs). We have previously demonstrated increased tubulointerstitial recruitment of human transforming growth factor-β (TGF-β)-producing DCs in renal fibrosis and chronic kidney disease (CKD). However, little is known about the mechanism of human DC recruitment and retention within the renal interstitium. We identified CD1c+ DCs as the predominant source of profibrotic TGF-β and highest expressors of the fractalkine receptor CX3CR1 within the renal DC compartment. Immunohistochemical analysis of diseased human kidney biopsies showed colocalization of CD1c+ DCs with fractalkine-positive proximal tubular epithelial cells (PTECs). Human primary PTEC activation with interferon-γ and tumor necrosis factor-α induced both secreted and surface fractalkine expression. In line with this, we found fractalkine-dependent chemotaxis of CD1c+ DCs to supernatant from activated PTECs. Finally, in comparison with unactivated PTECs, we showed significantly increased adhesion of CD1c+ DCs to activated PTECs via a fractalkine-dependent mechanism. Thus, TGF-β-producing CD1c+ DCs are recruited and retained in the renal tubulointerstitium by PTEC-derived fractalkine. These cells are then positioned to play a role in the development of fibrosis and progression of chronic kidney disease.

Soluble FGL2 induced by tumor necrosis factor-α and interferon-γ in CD4+ T cells through MAPK pathway in human renal allograft acute rejection

BACKGROUND

Acute rejection (AR), initiated by alloreactive CD4(+) T cells, hampers allograft survival. Soluble fibrinogen-like protein 2 (sFGL2) is a novel effector of CD4(+) T cells. We previously found that serum sFGL2 significantly increased in renal allograft recipients with AR. In this study, sFGL2 secretion by CD4(+) T cells and its mechanism were further explored both in vivo and in vitro.

MATERIALS AND METHODS

Forty cases of living-related renal transplant recipients with biopsy-proven AR or stable renal function were collected and detected serum sFGL2, tumor necrosis factor (TNF)-α and interferon (IFN)-γ, and peripheral CD4(+) T cells. In vitro, the isolated human CD4(+) T cells were stimulated by TNF-α or IFN-γ. sFGL2 in the supernatant and mitogen-activated protein kinase (MAPK) proteins in the CD4(+) T cells were investigated. Approval for this study was obtained from the Ethics Committee of Fudan University.

RESULTS

sFGL2, TNF-α, IFN-γ, and CD4(+) T cells were significantly increased in the peripheral blood of renal allograft recipients with AR. Stimulation with 1000 U/mL TNF-α or 62.5 U/mL IFN-γ for 48 h provided an optimal condition for CD4(+) T cells to secrete sFGL2 in vitro. Phosphorylated (p-) c-Jun N-terminal kinase was remarkably upregulated in the activated CD4(+) T cells, whereas no significant changes were found in p-p38 MAPK or p-ERK1/2 expression. Furthermore, inhibition of c-Jun N-terminal kinase significantly reduced sFGL2 secretion by CD4(+) T cells.

CONCLUSIONS

sFGL2 secretion by CD4(+) T cells can be induced with TNF-α and IFN-γ stimulation through MAPK signaling in renal allograft AR. Our study suggests that sFGL2 is a potential mediator in the pathogenesis of allograft rejection.

Ischaemic/reperfusion injury: Role of infliximab

Ischaemia/reperfusion (I/R) injury is an underlying complex interrelated patho-physiological process which effects the outcome of many clinical situations, in particular transplantation. Tumor necrosis factor (TNF)-α is a pleiotropic inflammatory cytokine; a trimeric protein encoded within the major histocompatibility complex which plays a pivotal role in this disease process. This review is based at looking into an update, particularly the new insights in the mechanisms of action of TNF antagonist such as infliximab. Infliximab may thus play a dual role in the field of transplantation where it might not only down regulate the I/R injury, it may also have a beneficial role in the reduction of acute rejection.

MCP-1: chemoattractant with a role beyond immunity: a review

BACKGROUND

Monocyte Chemoattractant Protein (MCP)-1, a potent monocyte attractant, is a member of the CC chemokine subfamily. MCP-1 exerts its effects through binding to G-protein-coupled receptors on the surface of leukocytes targeted for activation and migration. Role of MCP-1 and its receptor CCR2 in monocyte recruitment during infection or under other inflammatory conditions is well known.

METHOD

A comprehensive literature search was conducted from the websites of the National Library of Medicine (http://www.ncbl.nlm.nih.gov) and Pubmed Central, the US National Library of Medicine's digital archive of life sciences literature (http://www.pubmedcentral.nih.gov/). The data was assessed from books and journals that published relevant articles in this field.

RESULT

Recent and ongoing research indicates the role of MCP-1 in various allergic conditions, immunodeficiency diseases, bone remodelling, and permeability of blood - brain barrier, atherosclerosis, nephropathies and tumors.

CONCLUSION

MCP-1 plays an important role in pathogenesis of various disease states and hence MCP-1 inhibition may have beneficial effects in such conditions.

Association of high IFN-gamma plasma levels with low B-cell counts in renal transplant recipients with stable long-term graft function

Recently, we reported that patients with long-term stable good graft function had higher interferon-gamma (IFN-gamma) and lower IL-4 plasma levels late as compared with early post-transplant. These patients had more often detectable CD3(+)CD4(+)CD25(+)IFN-gamma(+)Foxp3(+) peripheral blood lymphocytes (PBL) late post-transplant than patients with impaired graft function. We therefore speculated that high plasma IFN-gamma late post-transplant might contribute to the maintenance of graft acceptance. Using ELISA and four-color flow cytometry, plasma cytokines and PBL subpopulations were measured in 65 renal transplant recipients with stable graft function late post-transplant. High IFN-gamma plasma levels were associated with low CD19(+) B PBL (r = -0.329; p = 0.009) and low activated CD3(+)CD8(+)DR(+) T PBL (r = -0.266; p = 0.035). Plasma IFN-gamma increased with time post-transplant (r = 0.288; p = 0.022) and was not associated with the dose of immunosuppressive drugs (p = n.s.). High plasma IFN-gamma was not associated with serum creatinine (r = 0.038; p = 0.765). Five patients showed evidence of chronic allograft nephropathy in previous biopsies and none of them exhibited increased plasma IFN-gamma. In patients with good long-term graft function, high IFN-gamma plasma levels were associated with low numbers of B PBL and activated CD8(+) T PBL. High IFN-gamma plasma levels might prevent the development of an immunological alloresponse and thereby contribute to the maintenance of graft acceptance.

Aqueous humor alloreactive cell phenotypes, cytokines and chemokines in corneal allograft rejection

As biopsies are not taken at the time of human corneal allograft rejection, most information on the early cellular changes in rejection is from animal models. We examined the phenotype of alloreactive cells present in the human anterior chamber during corneal graft rejection by flow cytometry and quantified aqueous humor levels of cytokines and chemokines using cytometric bead array. Aqueous and peripheral blood samples were taken from patients with graft endothelial rejection (n = 11) and from control patients undergoing cataract surgery (n = 8). CD45(+)CD4(+), CD45(+)CD8(+) and CD45(+)CD14(+) cells were found in aqueous during rejection; no CD45(+) cells were seen in control samples. Higher proportions of CD45(+) cells found in aqueous during rejection were CD14(+), denoting monocyte/macrophage lineage, than were CD4(+) or CD8(+). Large elevations were seen in aqueous levels of IL-6, MCP-1 and IP-10 during rejection compared with controls; smaller but still statistically significant increases were seen in MIP-1alpha and eotaxin. The role of CD14(+) cells in allorejection is unclear as is the potential of these chemokines and their receptors as therapeutic targets. Aqueous humor samples offer a unique opportunity to analyze components of the allogeneic response in direct contact with donor tissue but without artifacts inherent in examination of tissue.

Intrarenal Cytokine and Chemokine Gene Expression and Kidney Graft Outcome

AIMS

Proinflammatory cytokines are thought to play an important role in various kidney graft diseases resulting in interstitial fibrosis and tubular atrophy frequently found in case biopsies. To explore the role of various cytokines and chemokines in the long-term graft outcome, the transcription patterns of their genes in kidney allograft biopsies were evaluated.

METHODS

The real-time RT-PCR was used to identify intragraft mRNA expression of cytokines and chemokines in 74 kidney graft recipients and the results were correlated with histological and clinical parameters and long-term graft outcome.

RESULTS

We observed up-regulated IL-10 (p < 0.001), TGF-beta1, IL-6, MCP-1, RANTES (p < 0.01) and TNF-alpha (p < 0.05) mRNA expression in patients with chronic allograft nephropathy (CAN) as compared to controls. There were positive correlations between the mRNA expression of IL-6 (p < 0.001), IL-10 (p < 0.01), TNF-alpha, MCP-1 (p < 0.05) and the proteinuria. The up-regulation of intrarenal MCP-1 in patients with CAN increased the risk for the graft failure within the next 42 months (OR 5.1, p < 0.05). Kaplan-Meier survival analysis revealed that proteinuria and higher intragraft expression of TGF-beta1 and MCP-1 predict a poor kidney graft outcome.

CONCLUSION

Expression patterns of intrarenal proinflammatory genes might discriminate patients at a higher risk for the earlier allograft failure.

Renal Allograft Immune Response Is Influenced by Patient and Donor Cytokine Genotypes

This study investigated the impact of specific cytokine genotypes on the incidence of acute rejection episodes (ARE), chronic graft dysfunction (CGD), and anti-HLA donor-specific antibody (DS-Ab) production in 86 renal transplant recipients and 70 cadaveric donors. A PCR-SSP method was performed for the analysis of polymorphisms in TNF-alpha, IL-6, TGF-beta, IL-10, and IFN-gamma cytokines. DS-Ab monitoring of sera was performed using a FCXM analysis. Observed cytokine frequencies for patients and donors were not significantly different from the expected frequencies under Hardy-Weinberg equilibrium conditions. The evaluation in recipients revealed a higher frequency of DS-Ab-positive patients among the TNF-alpha high (50.0% vs 25.7%), and for the IL-10 cytokine a greater incidence of ARE-positive patients (35.8% vs 18.2%) with the high + intermediate, compared with the low genotype. The combined effect of these 2 genotypes predisposed to DS-Abs (71.4% vs 25.3%; P = 0.02; odds ratio [OR] = 7.37). As for the TGF-beta1 cytokine, we observed a higher number of CGD-positive patients among high compared with intermediate producers (14.3% vs 0%; P = .050). The analysis of donors revealed a significantly lower incidence of ARE-positive patients among recipients whose donors were carriers of the high IL-6 G/G-genotype compared with the G/C+C/C-genotypes (16.7% vs 41.2%; P = .03), suggesting a protective effect of the G/G genotype on ARE and a predisposing role of donor (-174)allele C. In addition, we noted an association between the IFN-gamma low A/A-genotype and a higher incidence of ARE (42.1% vs 0%; P = .002) and DS-Ab production (47.4% vs 12.5%; P = .02) compared with high producers.

Evidence for IFN-? up- and IL-4 downregulation late post-transplant in patients with good kidney graft outcome

We found recently that patients with good graft outcome showed higher IFN-gamma and IL-2, and lower IL-10 plasma levels late post-transplant than early post-transplant. In this retrospective study, we compared cytokine plasma levels in 33 symptom-free outpatients with those of 33 renal transplant recipients with early acute rejection (EAR), 29 with chronic rejection (CR), and 34 healthy controls (HC) to assess whether there is evidence for Th1 activation late post-transplant in patients with good graft outcome. Cytokines were measured pre-transplant, one wk, one month, six months, one yr, and two yr after transplantation. Twelve and 24 months post-transplant, IFN-gamma plasma levels were significantly higher (p = 0.001; p = 0.001, respectively) and IL-4 plasma levels significantly lower (p = 0.028; p = 0.003, respectively) in patients with stable graft function than those in controls. Six, 12, and 24 months post-transplant, patients with stable graft function had similar IFN-gamma and IL-4 plasma levels as patients with successfully treated EAR (p = n.s.), and higher IFN-gamma (p = 0.013; p = 0.001; p = 0.0005, respectively) and lower IL-4 (p = 0.007; p = 0.417; p = 0.0001, respectively) plasma levels than patients with CR. These data suggest that increased plasma IFN-gamma and decreased plasma IL-4 late post-transplant might be involved in the induction of mechanisms that facilitate good long-term graft outcome.

Fish oil for kidney transplant recipients

BACKGROUND

Calcineurin inhibitors used in kidney transplantation for immunosuppression have adverse effects that may contribute to nephrotoxicity and increased cardiovascular risk profile. Fish oils are rich in very long chain omega-3 fatty acids, which may reduce nephrotoxicity by improving endothelial function and reduce rejection rates through their immuno-modulatory effects. They may also modify the cardiovascular risk profile. Hence, fish oils may potentially prolong graft survival and reduce cardiovascular mortality.

OBJECTIVES

To assess the benefits and harms of fish oil supplementation on kidney transplant recipients on a calcineurin inhibitor-based immunosuppressive regimen.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library, issue 2 2005), MEDLINE (1966-April 2005) and EMBASE (1980-April 2005).

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs of fish oils in kidney transplant recipients on a calcineurin inhibitor-based immunosuppressive regimen. RCTs of fish oil versus statins were included.

DATA COLLECTION AND ANALYSIS

Data was extracted and the quality of studies assessed by two authors, with differences resolved by discussion with a third independent author. Dichotomous outcomes were reported as relative risk (RR) and continuous outcome measures were reported as the mean difference (MD) with 95% confidence intervals using the random effects model. Heterogeneity was assessed using a Chi(2) test on n-1 degrees of freedom and the I(2) statistic. Data not suitable for pooling were tabulated and described.

MAIN RESULTS

Sixteen studies (733 patients) were suitable for analysis. Fish oil did not significantly affect patient or graft survival, acute rejection rates, calcineurin inhibitor toxicity or renal function, when compared to placebo. Fish oil treatment was associated with a lower diastolic blood pressure (MD 4.5 mmHg; P = 0.004) compared to placebo. Patients receiving fish oil for more than six months had a modest increase in HDL (MD 0.12 mmol/L; P = 0.01) compared to placebo. Fish oil effects on lipids were not significantly different from low-dose statins. There was insufficient data to analyse cardiovascular outcomes. Fishy aftertaste and gastrointestinal upset were common but did not result in significant patient drop-out.

AUTHORS' CONCLUSIONS

There is insufficient evidence from currently available RCTs to recommend fish oil therapy to improve renal function, rejection rates, patient survival or graft survival. The improvements in HDL cholesterol and diastolic blood pressure were too modest to recommend routine use. To determine a benefit in clinical outcomes, future RCTs will need to be adequately powered with these outcomes in mind.

In situ expression of mononuclear cell markers and interleukin-2 receptor in renal allograft biopsies of acute rejection and borderline cases

The correct diagnosis of renal allograft rejection may be difficult using only clinical and/or histopathological criteria. Immunological assays should be considered in order to evaluate the phenotype of inflammatory infiltrate in renal allograft biopsies. Immunohistochemical studies were performed to detect mononuclear cells, CD4 and CD8 T lymphocytes, B lymphocytes, macrophages, null cells, and positive cells for interleukin-2 receptors. A total of 41 allograft biopsies classified into three groups were studied: acute cellular rejection (28 biopsies/22 patients), borderline (7 biopsies/5 patients) and control (6 biopsies/6 patients). In the rejection group (RG), increased cellularity was found mainly at the tubulo-interstitial level. Expression of CD8 positive cells was higher in RG when compared to borderline (BG) and control (CG) groups, respectively (0.9 vs. 0.0 vs. 0.35 cells/mm2; p < 0.001). Expression of macrophages was not statistically significant among the three groups (RG = 0.6 vs. BG = 0.2 vs. CG = 0.0 cells/mm2; p < 0.02). In the BG, CD4 + cells predominated (BG = 0.2 vs. RG = 0.05 vs. CG = 0.0 cells/mm2; p < 0.05). Clinically these patients were treated as cases of acute rejection. The numbers and different types of infiltrating cells did not correlate with patient's clinical outcome.

Human allograft arterial injury is ameliorated by sirolimus and cyclosporine and correlates with suppression of interferon-gamma

BACKGROUND

Chronic allograft dysfunction may result from arterial injury, manifest as transplant arteriosclerosis (TA). This represents an important factor limiting long-term outcomes after heart and kidney transplantation; a relationship between acute allograft arterial injury and TA has been suggested. We have used SCID/bg mice bearing transplanted human artery, inoculated with allogeneic human PBMC to study arteriopathy in human vessels. Earlier work demonstrated arteriopathy similar to that observed clinically, and identified interferon-gamma as a mediator of the process. This study evaluated whether sirolimus (SRL), with cyclosporine A (CsA) or alone, affects TA, and examined possible mechanisms of action.

METHODS

CB17/SCID/bg mice were transplanted with human arteries replacing the abdominal aorta; reconstituted with allogeneic human PBMC. Controls received vehicle alone for comparison with mice given CsA (5 mg/kg/d), SRL (0.1 or 0.5 mg/kg/d), or CsA (5 mg/kg/d) plus SRL (0.1 mg/kg/d). Transplant arteries were examined 28 days later by histology and immunohistochemistry; circulating human interferon-gamma was evaluated by ELISA, and intragraft interferon-gamma mRNA by qRT-PCR.

RESULTS

The characteristic TA was modestly reduced by CsA or low-dose SRL, but eliminated by combination CsA plus SRL or higher dose SRL alone. Circulating interferon-gamma was reduced by CsA, but inhibition was dramatic with SRL alone or combined with CsA. Intragraft interferon-gamma and HLA-DR expression were moderately reduced by CsA or SRL, and eliminated with combined CsA plus SRL.

CONCLUSIONS

SRL plus CsA prevented allograft arteriopathy, correlating with suppression of intragraft interferon-gamma, suggesting that SRL effects may result from anti-inflammatory consequences from inhibiting interferon-gamma.

Contributions of intrinsic renal cells to crescentic glomerulonephritis

The pro-inflammatory contributions of leukocytes, particularly macrophages and T cells, to the immunopathogenesis of proliferative forms of glomerulonephritis (GN) have been clearly established by various techniques, including in vivo depletion studies in experimental models. The evidence for an active pro-inflammatory role for intrinsic renal cells in GN has relied on studies demonstrating their production of pro-inflammatory mediators in vitro and during the development of GN. Until recently,the specific in vivo contributions of mediators from intrinsic renal cells to inflammatory injury in GN have proven difficult to define. Utilising 'chimeric' mice as a tool, several studies have explored the involvement of intrinsic renal cells via their production of cytokines and other key pro-inflammatory molecules. These studies provide evidence of important functional contributions of intrinsic renal cells to inflammatory injury in GN via their expression of cytokines, cytokine receptors, MHC-II and co-stimulatory molecules. They suggest a sequence of interactions between cytokines from leukocytes and intrinsic renal cells and important contributions of glomerular epithelial cell proliferation to crescent formation.

Osteopontin expression in acute renal allograft rejection

BACKGROUND

Osteopontin (OPN) is a potent chemoattractant for mononuclear cells that is up-regulated in various inflammatory states of the kidney. The role of OPN and its expression in human renal allograft rejection are unknown.

METHODS

We examined by immunohistochemistry and in situ hybridization, renal biopsies from patients with acute rejection (N= 22), protocol biopsies without rejection (N= 9), and perioperative donor biopsies (N= 35) for intrarenal expression of OPN, and its correlation with clinical, laboratory, and histopathologic parameters. In the rejection biopsies, interstitial monocyte/macrophage infiltration, tubulointerstitial cell proliferation/regeneration and apoptosis were investigated.

RESULTS

In the majority of rejection biopsies, OPN expression by proximal tubular epithelium was widespread, and tended to be enhanced in the tubules surrounded by numerous inflammatory cells. Conversely, in patients that did not experience episodes of rejection and in donor biopsies, OPN expression by proximal tubules was nil or weak. OPN mRNA was colocalized with its translated protein in the renal tubular epithelium. OPN expression positively correlated with the degree of interstitial inflammation (P < 0.05), CD68+ monocyte infiltration (P < 0.01), Ki-67+ regenerating tubular and interstitial cells (P < 0.05 and P < 0.005, respectively), but not with terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL)-positive apoptotic tubular cells.

CONCLUSION

These data suggest that inducible expression of OPN in the tubular epithelium may have a pathogenic role in acute renal allograft rejection by mediating interstitial monocyte infiltration and possibly tubular regeneration.

Cytokines and Chemokine Gene Expression in Human Kidney Transplantation

Despite advances in immunosuppression in past decades, allograft rejection remains the main reason for kidney graft failure. Recently, despite great improvements in understanding of molecular basis of allograft rejections, renal histology remains the primary method to monitor the onset of graft rejection. The aim of the present study was to ascertain whether cytokine and chemokine expression profiles in kidney allografts contributed to the diagnosis of graft dysfunction. We analyzed mRNA expression in 174 kidney graft biopsies for the following cytokines: TGF-beta1, TNF-alpha, IL-10, and chemokine RANTES. Based on the expression levels obtained by real-time RT-PCR, we correlated data with the results of morphologic examinations. All tested cytokines and chemokines were upregulated (P < .001) during acute rejection compared to nonrejecting controls. Upregulation was also found in chronic allograft nephropathy (CAN) group for TGF-beta1, IL-10 (P < .001), TNF-alpha, and RANTES (P < .01). Upregulated expression of IL-10 (P < .001), TGF-beta1, (P < .01) and RANTES (P < .05) showed borderline changes. Higher expression levels (P < .001) of TGF-beta1 and IL-10 were also found during ATN. IL-10 was upregulated (P < .01) in specimens with recurrent glomerulonephritis. Weakly increased (P < .05) expressions of TGF-beta1 were found during CsA toxicity. Distinctive expression levels between acute rejection and CAN were only found for IL-10 (P < .01). TNF-alpha showed a different expression profile in acute rejection versus ATN (P < .001). These findings suggest that distinct cytokine and chemokine expression profiles in grafts may contribute to the diagnosis for and elucidation of the immunopathologic process during graft dysfunction.

Prevalence and immunohistochemical findings of subclinical kidney allograft rejection and its association with graft outcome

Subclinical acute rejection (SAR) occurs in about 30% of stable renal transplant patients and may be a risk factor for a poor allograft outcome. In the present study, the prevalence and clinical features of subclinical rejection, and the expression of immune activation markers in surveillance graft biopsies were assessed and correlated with late graft outcomes. Protocol biopsies were obtained at 2 and 12 months post-transplant in 32 and 26 patients, respectively, with stable renal function. The Banff 1997 criteria were used for histological diagnosis. Graft function and survival and proteinuria were assessed during the 36 months of follow-up. Immunohistochemical evaluation of cell subpopulations and immunoactivation markers were performed on protocol biopsies. The prevalence of SAR at 2 months and of chronic allograft nephropathy (CAN) at 12 months in representative biopsies was 55 and 50%, respectively. Patients with SAR presented mononuclear cell infiltration with an increased expression of CD3, CD4, CD68, IL-2R and granzyme B. Kidney graft function was significantly worse in patients with SAR at 2 months who had chronic rejection on biopsy at 12 months, but SAR was not associated with a worse graft function, greater proteinuria or a lower graft survival in 3 yr of follow-up. In conclusion, we found an elevated prevalence of SAR at 2 months after transplantation with an increased expression of activation markers. Although an association of SAR with poor graft outcome was not observed, our results suggest that SAR is an immunologically active process and underscore the importance of protocol biopsies in the surveillance of transplanted kidneys.

Cyclooxygenase-2 (COX-2) inhibition limits abnormal COX-2 expression and progressive injury in the remnant kidney

BACKGROUND

The pathogenesis of progressive nephropathies involves hemodynamic and inflammatory factors. In the 5/6 nephrectomy model, a selective increase of cyclooxygenase-2 (COX-2) expression was shown, whereas treatment with a nonsteroidal anti-inflammatory or a specific COX-2 inhibitor was renoprotective. We investigated in the 5/6 nephrectomy model (1) the renal distribution of COX-2; (2) the hemodynamic and cellular mechanisms by which chronic COX-2 inhibition prevents renal injury.

METHODS

After 5/6 nephrectomy, adult male Munich-Wistar rats were subdivided in two groups: 5/6 nephrectomy (N=20), receiving vehicle, and 5/6 nephrectomy + celecoxib (N=19), treated orally with the COX-2 inhibitor, celecoxib, 10 mg/kg/day. Untreated and treated (celecoxib) sham-operated rats were also studied. Renal hemodynamics were examined at 4 weeks, whereas renal morphologic/immunohistochemical studies were carried at 8 weeks.

RESULTS

At 4 weeks, 5/6 nephrectomy rats exhibited marked systemic and glomerular hypertension. Celecoxib attenuated both systemic and glomerular hypertension, without affecting glomerular filtration rate (GFR). At 8 weeks, glomerulosclerosis and interstitial expansion were evident in 5/6 nephrectomy rats, and markedly attenuated in 5/6 nephrectomy rats given celecoxib. In both sham-operated and 5/6 nephrectomy rats, COX-2 was expressed at the macula densa. The extent of COX-2 expression at the macula densa was nearly tripled by celecoxib, indicating the existence of a feedback mechanism. In 5/6 nephrectomy rats, COX-2 was also expressed in glomeruli, arterioles, and the cortical interstitium, mostly at inflamed or sclerosing areas. Celecoxib markedly attenuated renal injury, inflammation, and ectopic COX-2 expression in 5/6 nephrectomy rats.

CONCLUSION

Chronic COX-2 inhibition attenuated progressive nephropathy by reducing glomerular hypertension, renal inflammation, and ectopic COX-2 expression, indicating a complex contribution of COX-2 to progressive renal injury in 5/6 nephrectomy rats.

Influence of IFN-γ polymorphism on the development of coronary vasculopathy after cardiac transplantation

BACKGROUND

The development of coronary vasculopathy (CV) limits survival after cardiac transplantation. Interferon (IFN)-gamma is an important immunomodulator affecting the growth and function of T cells and macrophages, free radical formation, adhesion molecule, and MHC class I and II expression, which are important processes for CV formation. IFN-gamma is expressed early after transplantation and neutralization or genetic absence of the cytokine can abrogate CV development. The expression of IFN-gamma is influenced by a dinucleotide repeat in the first intron of the IFN-gamma gene. We investigated the effect of this polymorphism on the development of CV.

METHODS

Using sequence specific primers to the IFN-gamma polymorphic region, polymerase chain reaction (PCR) and gel electrophoresis identified the genotype in 144 cardiac transplant recipients and 134 donors. An association was sought between the presence of a high, intermediate or low IFN-gamma producing genotype and the development of CV diagnosed by routine surveillance posttransplant angiography.

RESULTS

High, intermediate, and low IFN-gamma producers made up 29.2%, 44.4%, 26.4% and 24.6%, 40.3%, 35.1% of recipients and donors respectively (p = NS). IFN-gamma polymorphism in cardiac graft recipients had no impact on the time to first diagnosis of CV; high producers 4.03 years (+/- 129.9 days), intermediate producers 3.40 years (+/- 79.7 days), low producers 4.01 years (+/- 102.9 days); p = 0.16. Similar results were found on investigating donor polymorphism; high producers (3.68 years +/- 120.1 days), intermediate producers (3.83 years +/- 105.9 days), low producers (3.3 years +/- 77.7 days); p = 0.35. Multivariate analysis identified the number of rejection episodes of ISHLT grade 3 or greater and increasing donor age to be independent risk factors for CV development.

CONCLUSIONS

Dinucleotide repeat polymorphism in the first intron of the human IFN-gamma gene does not influence CV development and cannot be used as a genetic risk marker.

IL-1beta, TNF-alpha, TGF-beta, and bFGF expression in bone biopsies before and after parathyroidectomy

BACKGROUND

There is growing evidence pointing to an involvement of cytokines and growth factors in renal osteodystrophy. In this study, the expression of interleukin-l beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), and basic fibroblast growth factor (bFGF) in bone biopsies taken from uremic patients before and 1 year after parathyroidectomy (PTX) was evaluated. Biochemical features and histomorphometric outcome were also studied.

METHODS

Iliac bone biopsies were taken before and 1 year after PTX in nine uremic patients with severe hyperparathyroidism (HPT). Immunohistochemical techniques were used to identify the expression of IL-1 beta, TNF-alpha, TGF-beta, and bFGF in these bone samples.

RESULTS

At the time of the second bone biopsy, the mean serum total alkaline phosphatase activity was normal, whereas mean serum intact parathyroid hormone (iPTH) level was slightly above the upper limit of normal values. Histomorphometric analysis showed a decrease in resorption parameters and static bone formation parameters after PTX. Dynamically, mineral apposition rate (MAR) and mineralization surface (MS/BS) decreased significantly. There was a marked local expression of IL-1beta, TNF-alpha, TGF-beta, and bFGF in bone biopsies before PTX, particularly in fibrous tissue and resorption areas. One year after PTX, IL-1beta decreased from 23.6 +/- 7.5% to 9.9 +/- 3.1%, TNF-alpha from 4.5 +/- 1.5% to 0.7 +/- 0.8%, TGF-beta from 49.6 +/- 9.8% to 15.2 +/- 4.6%, and bFGF from 50.9 +/- 12.7% to 12.9 +/- 7.9% (P < 0.001). A significant correlation was documented between cytokines and growth factors expression in bone with iPTH levels before and after PTX (P < 0.05).

CONCLUSIONS

Based on these results, we suggest that IL-1beta, TNF-alpha, TGF-beta, and bFGF are involved in bone remodeling regulation, acting as local effectors, possibly under the control of PTH.

Fractalkine expression on human renal tubular epithelial cells: potential role in mononuclear cell adhesion

Fractalkine (CX3CL1) is a transmembrane molecule with a CX3C chemokine domain attached to an extracellular mucin stalk which can induce both adhesion and migration of leucocytes. Mononuclear cell infiltration at renal tubular sites and associated tubular epithelial cell damage are key events during acute renal inflammation following renal allograft transplantation. Using northern and Western blot analysis, we have demonstrated the expression of fractalkine message and protein by renal tubular epithelial cells in vitro. The expression was up-regulated by TNF-alpha, a key proinflammatory cytokine in acute rejection. Investigation of surface expression of fractalkine on cultured proximal tubular epithelial cells revealed only a subpopulation of positively staining cells. Immunohistochemistry revealed that only a proportion of tubules in renal allograft biopsies showed induction of fractalkine expression. Studies using a static model of adhesion demonstrated CX3CR1/fractalkine interactions accounted for 26% of monocytic THP-1 cell and 17% of peripheral blood natural killer cell adhesion to tubular epithelial cells, suggesting that fractalkine may have a functional role in leucocyte adhesion and retention, at selected tubular sites in acute renal inflammation. Thus, fractalkine blockade strategies could reduce mononuclear cell mediated tubular damage and improve graft survival following kidney transplantation.

Interleukin-1 receptor antagonist as a biomarker for bronchiolitis obliterans syndrome in lung transplant recipients

BACKGROUND

The major limitation to survival after lung transplantation is bronchiolitis obliterative syndrome (BOS). BOS is a chronic inflammatory/immunologic process characterized by fibroproliferation, matrix deposition, and obliteration of the airways. The mechanism(s) that lead to fibro-obliteration of allograft airways have not been fully elucidated. Interleukin-1 receptor antagonist (IL-1Ra) is a naturally occurring antagonist of the pro-inflammatory cytokine IL-1 and has been associated with a number of fibroproliferative diseases.

METHODS

We determined whether IL-1Ra, as compared to IL-1beta, IL-10, transforming growth factor (TGF)-beta, and tumor necrosis factor (TNF)-alpha, in the bronchoalveolar lavage fluid (BALF) from lung transplant recipients was associated with BOS. BALF was collected from three groups of patients: BOS (n=22), acute rejection (n=33), and healthy transplant recipients (n=30).

RESULTS

IL-1Ra levels were significantly elevated in patients with BOS compared to healthy lung transplant recipients and patients with acute rejection (P<0.001 and P<0.05, respectively). Furthermore, when patients with BOS had their BALF analyzed from their last bronchoscopy before the development of BOS (Future BOS [FBOS] group) (n=20), their levels of IL-1Ra were also significantly elevated compared to healthy lung transplant recipients and patients with acute rejection (P<0.001 and P<0.05, respectively). Importantly, the elevated levels of IL-1Ra in the BOS and FBOS groups were not accompanied by any significant increases in IL-1beta, IL-10, TGF-beta, or TNF-alpha.

CONCLUSION

These findings suggest that elevated levels of IL-1Ra may be attenuating IL-1 bioactivity during the pathogenesis of BOS and creating a local environment that favors fibroproliferation and matrix deposition.

Fractalkine expression in human renal inflammation

Immune and inflammatory human renal disease is associated with heavy mononuclear cell infiltration. The trafficking of these cells to extravascular sites is directed by local production of chemokines. Fractalkine is the first described cell-surface anchored chemokine and has potent mononuclear cell-directed adhesion and chemotactic properties. The purpose of this study was to analyse the expression and distribution of fractalkine in human renal inflammation. In situ hybridization and immunohistochemistry were used to study renal biopsies from 15 patients with predominant glomerular inflammation (vasculitic glomerulonephritis) and 15 with predominant tubular and interstitial inflammation (acute renal allograft rejection). Controls comprised non-inflammatory glomerulonephritis and normal tissue. Fractalkine mRNA was predominantly expressed in the major compartment, glomerular or tubulointerstitial, affected by disease and with the strongest expression localized to vascular sites local to inflammation. In acute renal allograft rejection, there was increased expression of fractalkine mRNA by tubular epithelial cells. There was no expression of fractalkine by infiltrating leukocytes and there was only sparse expression in control tissue. Fractalkine mRNA expression correlated with infiltrating leukocyte subsets. Immunohistochemistry confirmed this pattern of expression, with serial section co-localization showing fractalkine expression in areas with macrophage (CD68+) and T cell (CD3+) infiltrates. These expression patterns show that fractalkine is a strong candidate for directing mononuclear cell infiltration in human renal inflammation.

The role of cytokine polymorphisms in rejection after solid organ transplantation

The importance of cytokines to the immune response is irrefutable. Their role in the biology of solid organ transplantation per se is also assured. Thus it is likely that subtle differences in cytokine composition, particularly at the initiation of an immune response, may have a major effect on the outcome of that response. This may be particularly relevant in solid organ transplantation, where it is possible that genetic polymorphisms which influence cytokine production may determine the outcome of a transplant. Indeed, it has been suggested that immunosuppression may be individualised on the basis of recipient or donor genotype. However, much of the early data regarding the importance of specific cytokine polymorphisms has not been reproduced, and the significance of this field remains controversial. Nonetheless, with the experience gained from earlier studies, some clear patterns for future studies are emerging.

IFN-gamma alters the pathology of graft rejection: protection from early necrosis

We studied the effect of host IFN-gamma on the pathology of acute rejection of vascularized mouse heart and kidney allografts. Organs from CBA donors (H-2k) were transplanted into BALB/c (H-2d) hosts with wild-type (WT) or disrupted (GKO, BALB/c mice with disrupted IFN-gamma genes) IFN-gamma genes. In WT hosts, rejecting hearts and kidneys showed mononuclear cell infiltration, intense induction of donor MHC products, but little parenchymal necrosis at day 7. Rejecting allografts in GKO recipients showed infiltrate but little or no induction of donor MHC and developed extensive necrosis despite patent large vessels. The necrosis was immunologically mediated, since it developed during rejection, was absent in isografts, and was prevented by immunosuppressing the recipient with cyclosporine or mycophenolate mofetil. Rejecting kidneys in GKO hosts showed increased mRNA for heme oxygenase 1, and decreased mRNA for NO synthase 2 and monokine inducible by IFN-gamma (MIG). The mRNA levels for CTL genes (perforin, granzyme B, and Fas ligand) were similar in rejecting kidneys in WT and GKO hosts, and the host Ab responses were similar. The administration of recombinant IFN-gamma to GKO hosts reduced but did not fully prevent the effects of IFN-gamma deficiency: MHC was induced, but the prevention of necrosis and induction of MIG were incomplete compared with WT hosts. Thus, IFN-gamma has unique effects in vascularized allografts, including induction of MHC and MIG, and protection against parenchymal necrosis, probably at the level of the microcirculation. This is probably a local action of IFN-gamma produced in large quantities in the allograft.

Potential role for monocyte chemotactic protein-4 (MCP-4) in monocyte/macrophage recruitment in acute renal inflammation

The CC chemokine, monocyte chemoattractant protein-4 (MCP-4), is an important chemoattractant for monocytes and T cells. Recent data indicate a role in renal inflammation. This study has used in situ hybridization and immunohistochemical analysis of cryostat sections of biopsy material taken from patients with acute renal allograft rejection and vasculitic glomerulonephritis to demonstrate renal expression of MCP-4, both at message and protein level. MCP-4 was primarily expressed at peritubular, periglomerular, and perivascular sites, irrespective of the inflammatory condition, and was associated with infiltrating CD3-positive lymphocytes and CD68-positive monocyte/macrophages. In addition, proximal tubular epithelial cells grown in culture from cortical fragments of human kidney showed low levels of constitutive MCP-4 expression, detectable by western blotting; this expression of MCP-4 was up-regulated in response to the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). CCR3-, CCR5- and CCR2-expressing leukocyte populations were identified at sites of MCP-4 expression. Double-staining techniques revealed that CC chemokine receptor-expressing cells were primarily CD68-positive. These studies suggest an important role for MCP-4 in the recruitment and retention of monocytes/macrophages in renal inflammation.

Mycophenolate Mofetil Reduces Renal Injury in the Chronic Nitric Oxide Synthase Inhibition Model

-We and others have recently shown that mycophenolate mofetil (MMF) reduces renal inflammation and glomerular and interstitial injury in the 5/6 renal ablation model. In the present study, we investigated whether MMF limits renal injury in a model of chronic nitric oxide (NO) inhibition associated with a high-salt diet and characterized by progressive systemic hypertension, albuminuria, glomerular sclerosis and ischemia, interstitial expansion, and progressive macrophage infiltration. Adult male Münich-Wistar rats were distributed among 3 groups: HS, rats receiving a high-salt diet (3.2% Na); HS+N, HS rats orally treated with the NO inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME), 25 mg. kg(-1). d(-1); and HS+N+MMF, HS+N rats orally treated with MMF, 10 mg. kg(-1). d(-1). Renal hemodynamics were studied after 15 days of treatment; histological and immunohistochemical studies were conducted after 30 days of treatment. MMF treatment did not reverse the hemodynamic alterations characteristic of this model. Renal injury in the HS+N group was associated with macrophage and lymphocyte infiltration. Treatment with MMF reduced glomerular and interstitial injury and limited macrophage and lymphocyte infiltration. These results suggest that renal inflammation is a strong independent factor in the pathogenesis of the nephropathy associated with the HS+N model.

Local bioactive tumour necrosis factor (TNF) in corneal allotransplantation

The aim of this study was to examine the kinetic profile of bioactive TNF levels in aqueous humour of rabbit eyes undergoing corneal allograft rejection and to investigate the effect of locally blocking TNF activity after corneal transplantation. In a rabbit corneal transplantation, endothelial allograft rejection was identified and correlated with increase in central graft thickness. Samples of aqueous humour obtained on alternate days following transplantation were tested for TNF mRNA and bioactive TNF protein. To investigate the effect of locally blocking TNF activity in allograft recipients, the fusion protein TNFR-Ig was administered by injections into the anterior chamber after transplantation. Pulsatile increases in levels of this cytokine were found in 14 of 15 allograft recipients. Peaks of TNF bioactivity preceded by varying intervals the observed onset of rejection in allograft recipients. TNF levels were not elevated in aqueous humour from corneal autograft recipient controls or in serum of allografted animals. mRNA levels were elevated before onset of and during clinically observed allograft rejection. In three of seven animals receiving TNFR-Ig injections on alternate days from day 8 to day 16 post-transplant, clear prolongation of corneal allograft survival was demonstrated. Bioactive TNF is present in aqueous humour following rabbit corneal allotransplantation. Rather than correlating directly with endothelial rejection onset, pulsatile peak levels of TNF precede and follow the observed onset of endothelial rejection. Blockade of TNF activity prolongs corneal allograft survival in some animals, indicating that this cytokine may be a suitable target in local therapy of corneal allograft rejection.

Evidence for a genetic predisposition towards acute rejection after kidney and simultaneous kidney-pancreas transplantation

BACKGROUND

In vitro production of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin 10 (IL-10), and transforming growth factor-beta (TGF-beta) correlate with their respective genetic polymorphisms. We analyzed the relationship between these genetic polymorphisms and posttransplant outcome.

METHODS

Using DNA polymerase chain reaction (PCR) technology, polymorphisms for TNF-alpha, IFN-gamma, IL-10, and TGF-beta were determined for 82 kidney (K) and 19 simultaneous kidney-pancreas (SKP) recipients. These results were analyzed with regard to the incidence of acute rejection (AR), and the timing and severity of the first AR episode.

RESULTS

A high TNF-alpha production phenotype correlated with recurrent acute rejection (AR) episodes (P<0.026). Compared with the low TNF-alpha production phenotype, more patients with the high production phenotype had a post-AR serum creatinine >2.0 mg/dl, but this was not statistically significant (64 vs. 35%, P=0.12). There was no relationship between TNF-alpha genotype and the time to first AR episode or incidence of graft loss. IFN-gamma production phenotype showed no correlation with any of these clinical outcome parameters. There was an increase in AR incidence as the IL-10 production phenotype increased (low, intermediate, high), but only in low TNF-alpha producer phenotypes (P=0.023).

CONCLUSIONS

Patients with a polymorphic cytokine genotype putatively encoding for high in vivo TNF-alpha production, and to a lesser extent IL-10 cytokine genotypes putatively encoding for higher levels of in vivo IL-10 production, had a worse clinical outcome regarding AR episodes. These data support the hypothesis that the strength of alloimmune responsiveness after transplantation in part is genetically determined.

Effect of tacrolimus (FK506) and sirolimus (rapamycin) mono- and combination therapy in prolongation of renal allograft survival in the monkey

BACKGROUND

Our previous studies confirmed that tacrolimus (FK506) and sirolimus [rapamycin (RAPA)], in combination, are not antagonistic but are synergistic in the prolongation of heart and small bowel grafts in the rodent. The aim of this study was to confirm further the synergistic effect of combined FK506 and RAPA in the more clinically relevant model, kidney transplantation in monkeys.

METHODS

A total of 60 male Vervet monkeys were randomly assigned to 10 groups (n> or =5). Monkeys with renal allografts were treated with different doses of FK506 and/or RAPA orally for 60 days. Graft survival, body weight, clinical biochemistry determinations, oral glucose tolerance test, trough levels of the two drugs, and histopathology were investigated.

RESULTS

Low doses of FK506 (1 or 4 mg/kg) combined with RAPA (0.5 mg/kg) produced synergistic effect in the prolongation of renal graft survival [combination index (CI) = 0.292, 0.565]. There were no additive or synergistic drug-associated toxicities such as hyperglycemia, nephrotoxicity, and hyperlipidemia. There also was no pharmacological antagonism.

CONCLUSION

Concomitant therapy of low-dose (drug-optimal) FK506 and RAPA produced a synergistic effect in the prolongation of kidney allograft survival in Vervet monkeys without additive drug-associated toxicities.

Cyclosporine-induced interstitial fibrosis and arteriolar TGF-beta expression with preserved renal blood flow

BACKGROUND

Cyclosporine A (CsA)-induced chronic nephrotoxicity is characterized by interstitial fibrosis and afferent arteriole hyalinosis. CsA lesion has been linked to maintained renal vasoconstriction and narrowing of the afferent arteriole lumen diameter, leading to preglomerular ischemia. We investigated the role of renal hemodynamics in CsA-induced transforming growth factor (TGF-beta) expression and interstitial fibrosis.

METHODS

Groups of rats fed a low salt diet were given CsA 5 mg/kg/day (CsA) or the vehicle (olive oil, [VH]) s.c. and had the renal blood flow (RBF), glomerular filtration rate (GFR), mean arterial pressure, renal vascular resistance, renal histologic changes, and immunohistochemical features for macrophages and TGF-beta evaluated after 1, 2, and 8 weeks of treatment.

RESULTS

At week 1, despite normal renal hemodynamics and MAP, there was a significant macrophage interstitial influx in CsA-treated rats (70+/-16 vs. 29+/-4 cells+/0.5 mm2, in CsA vs. VH, P=0.02) that was progressive with treatment (80+/-13 vs. 32+/-8 cells+/0.5 mm2, P=0.016 and 197+/-36 vs. 23+/-3 cells+/0.5 mm2, P=0.0002, CsA vs. VH at 2 and 8 weeks, respectively). After 2 weeks of treatment, CsA animals developed a significant interstitial fibrosis, with preserved RBF, even when it was assessed 2 hr after CsA injection. There was a significant increase in the immunostaining for TGF-beta in the juxtaglomerular arterioles in CsA-treated rats (48.6+/-3.8 vs. 35.1+/-1.1%, CsA vs. VH at 2 weeks, P<0.05 and 59.0+/-3.2 vs. 37.0+/-2.1%, CsA vs. VH at 8 weeks, P=0.0001). A significant and progressive GFR decrease followed the renal structural injury of CsA treatment. Arteriolar and glomerular anatomic injury were not found throughout the study.

CONCLUSIONS

Low CsA doses might generate interstitial fibrosis without any decrease in RBF or structural arteriolar lesion evidence, possibly through early macrophage influx and increased TGF-beta expression. It clearly seems that CsA-induced ischemia and tubulointerstitial injury may occur independently, suggesting that chronic CsA nephrotoxicity may be very hard to prevent or even not be preventable at all.

Improved techniques for kidney transplantation in the monkey

Improved microsurgical techniques for kidney transplantation in the monkey are described. The left graft kidney is transplanted to the lower part of abdomen with end-to-side anastomoses of renal artery to aorta without a patch of aorta, renal vein to inferior vena cava, and end-to-end anastomosis of donor and recipient ureter with 8-0 nylon sutures in a bilateral nephrectomized recipient monkey. We recently performed 60 kidney transplantations in Vervet monkeys. None died of surgery or surgical complications. This reproducible model provides a useful tool to test new immunosuppressants and to investigate the mechanism of drug-induced tolerance and xenotransplantation in primates as a support to clinical trial.

Differences in Type 1 and Type 2 intracytoplasmic cytokines, detected by flow cytometry, according to immunosuppression (cyclosporine A vs. tacrolimus) in stable renal allograft recipients

Recent multicenter, randomized clinical trials have shown that in renal transplant patients tacrolimus (FK506) was more efficient than cyclosporine A (CsA) at preventing acute rejection. In order to try and evaluate whether this difference was related to a different in vivo T-cell suppression we assessed, in a prospective study, the frequencies of interleukin (IL)-2-, IL-4-, IL-5-, IL-6-, IL-10-, interferon-gamma (IFN-gamma)- and double-positive IL-2/IFN-gamma-producing whole T cells, CD4 + and CD8 + T-cell subsets by means of cytokine flow cytometry. This was performed after in vitro stimulation of peripheral blood mononuclear cells (PBMCs) with phorbol myristate acetate (PMA) and ionomycin, in the presence of monensin, in 14 healthy volunteers (controls) and in 14 renal transplant patients. The immunosuppression of the latter was based either on CsA (n = 7) or on FK506 (n = 7). Cytokine-expressing T-cell frequencies were assessed immediately pretransplantation (DO), and subsequently 3 months (M3) and 6 months (M6) afterwards in fasting patients prior to the morning intake of the immunosuppressive drug. We found that at DO the frequencies of IL-2-(22 +/- 2% vs. 22.2 +/- 2%), IFN-gamma-(26 +/- 3% vs. 29 + 3.4%) and IL-4-(0.8 +/- 0.2% vs. 1.4 +/- 0.2%)-expressing T lymphocytes were not significantly different between the controls and the patients, respectively. Conversely, the frequency of IL-2/IFN-gamma double positive cells was higher in the latter (9.3 +/- 1.6%) than in the controls (5.6 +/- 0.8); p = 0.06. Finally, on D0 the frequencies of IL-5-, IL-6-, and IL-10-producing T lymphocytes were lower than 1%, in both groups, as well as after grafting, i.e. on M3 and M6. As compared to baseline (DO): (a) chronic immunosuppression significantly decreased the frequencies of IL-2-, IL-4- and IL-2/IFN-gamma-expressing T cells, whereas those of IFN-gamma, IL-5, IL-6, and IL-10 were not significantly affected; (b) the frequencies of cytokine-expressing T cells were not statistically different between M3 and M6; (c) the decrease in the frequencies of IL-2- and IL-2/IFN-gamma-expressing T cells affected CD4 + and CD8 + cells equally; (d) there was a marginal decrease in the frequency of IFN-gamma-expressing cells only in the CD4 + subset but not in the CD8 population; and (e) for CsA, but not for FK506, the frequency of the IL-2-expressing T cells was negatively correlated with the whole blood trough levels. When we compared the frequencies of cytokine-expressing cells in FK506- and CsA-treated patients, we found that the frequency of IL-2-expressing T cells was significantly lower with FK506 (10.9+/-1.61%) than with CsA (16.3 +/- 1.8%; p = 0.03), whereas the frequencies of the other cytokine-expressing cells were not statistically different between the two groups. In conclusion, our study clearly demonstrated that studied ex vivo, FK506 and CsA decrease the frequencies of cells expressing IL-2, IL-4 and IL-2/IFN-gamma in vivo but do not affect those expressing IFN-gamma. Meanwhile, the frequency of IL-2-producing T cells was more affected with FK506 than with CsA and was negatively correlated with the CsA trough level. Finally, our results regarding IL-2 might explain to some extent the higher efficiency of FK506 in vivo than CsA.

Clinical rejection is distinguished from subclinical rejection by increased infiltration by a population of activated macrophages

It has been reported previously that one-third of protocol renal biopsies in asymptomatic, biochemically stable renal transplant recipients in the first 6 mo show unsuspected subclinical graft rejection (both infiltrate and tubulitis) and that subclinical rejection is a risk factor for chronic renal dysfunction. This study was performed to determine whether differences in phenotype or activation status of graft-infiltrating cells underlie these different manifestations of acute rejection. Biopsies with normal histology (n = 10), subclinical rejection (n = 13), and clinical rejection (n = 9) were studied using immunohistochemistry and computerized image analysis. Subclinical and clinical rejections had similar histologic Banff scores. Univariate analysis showed a trend for a higher infiltration with CD8+ (P = 0.053) and CD68+(P = 0.06) cells in clinical rejection. Of the activation markers studied (CD25, perforin, tumor necrosis factor-alpha), only allograft inflammatory factor-1+-activated macrophages were significantly (P = 0.014) increased in the infiltrate of clinical rejection biopsies. These data suggest that activated macrophages or their products are responsible for acute renal dysfunction associated with clinical rejection episodes.

T lymphocyte adhesion mechanisms within inflamed human kidney: studies with a Stamper-Woodruff assay

Renal inflammatory conditions are characterized by mononuclear cell recruitment to sites of inflammation. We have developed a modified Stamper-Woodruff assay system to analyze mechanisms of functional T cell adhesion to cryostat sections of renal biopsy material from patients with vasculitic glomerulonephritis (GN) and acute allograft rejection. Peripheral blood T cells adhered to intraglomerular, periglomerular, and tubulointerstitial regions of the cortex. Blocking monoclonal antibodies against tissue expressed ICAM-1, VCAM-1, and the CS-1 domain of fibronectin (CS-1Fn) differentially attenuated T cell adhesion. Glomerular adhesion in vasculitic GN and tubulointerstitial adhesion in acute rejection were particularly sensitive to both anti-ICAM-1 and anti-VCAM-1 antibodies, indicating a prominent role for ICAM-1 and VCAM-1 at glomerular sites in vasculitis and at tubulointerstitial sites in rejection. Furthermore, using KL/4 cells (LFA-1 expressing) and Jurkat cells (VLA-4 expressing), we demonstrated specific LFA-1/ICAM-1- and VLA-4/VCAM-1-mediated interactions within glomerular and tubulointerstitial compartments. Jurkat cells also adhered to VCAM-1-free sites, and binding was inhibitable by anti-CS-1Fn antibody, thereby demonstrating a role for VLA-4/fibronectin interactions especially at intraglomerular sites in acute rejection where VCAM-1 is notably absent. We therefore propose a prominent functional role for ICAM-1, VCAM-1, and CS-1 domain fibronectin in T cell recruitment to the inflamed kidney.

Analysis of primate renal allografts after T-cell depletion with anti-CD3-CRM9

BACKGROUND

FN18-CRM9 is a CD3-specific immunotoxin that is capable of depleting CD3+ T cells. Pretreatment of rhesus monkeys with this agent before transplantation can induce donor-specific tolerance and "split tolerance" to renal allografts.

METHODS

Heterotopic renal transplants were performed on monkeys that received posttransplant FN18-CRM9. Histological and immunohistological staining, as well as analysis of the intragraft cytokine profile by reverse transcriptase polymerase chain reaction, was performed on percutaneous allograft biopsies.

RESULTS

Experimental monkeys had significant prolongation of allograft survival. Although an interstitial, mononuclear cell infiltrate was seen in all of the renal transplants, there was minimal evidence of acute cellular rejection. Histological evidence of alloantibody-mediated damage was detected 3 to 5 months after transplantation in the monkeys treated with FN18-CRM9. Immunohistology demonstrated the reappearance of CD3+ and CD4+ T cells, as well as CD20+ B cells, in the grafts. Cytokine analysis demonstrated expression of interferon-gamma. An intact anti-donor IgG response was seen.

CONCLUSION

Treatment of monkeys with FN18-CRM9 immediately after transplantation significantly prolongs renal allograft survival. Allograft biopsies demonstrate a lack of acute cellular rejection; however, alloantibody-mediated graft damage and rejection occur, with an intact anti-donor IgG response. The intragraft expression of the interferon-gamma may reflect this ongoing humoral rejection. These data suggest that even a brief period of T-cell allosensitization may lead to humorally mediated allograft damage. Efforts to achieve tolerance with posttransplant FN18-CRM9 will require modification of the protocol to deplete T cells before allosensitization exposure or to supplement the posttransplant immunomodification strategy.