Chronic Renal Allograft Rejection Research Articles

Post Renal Transplant Castleman’s Disease Resolved After Graft Nephrectomy: A Case Report

Angiofollicular lymphoid hyperplasia (Castleman’s disease) is a lymphoproliferative process thought to be mediated by overexpression of II interleukin-6. Castleman’s disease has two variants: Castleman’s disease has two variants: Hyaline vascular type and plasma cell variant (multicentric Castleman’s disease). The hyaline vascular type tends to be localized, and the plasma cell variant shows more systematic signs and carriers a worse clinical prognosis. Castleman’s disease is associated with B-cell lymphoma, Kaposi sarcoma, Human herpes virus 8 (HHV-8), and Epstein-Barr virus. Castleman’s disease have been described thrice post kidney transplant. In this report, we document the course of a renal recipient who developed the plasma cell variant of Castleman’s disease at 16 months after failure of his allograft and return to dialysis. He displayed clinical resolution of this complication after graft nephrectomy. To our knowledge, this is the first case where the disease manifestations disappeared after graft removal. Our patient experienced chronic renal allograft rejection which may have driven all the systematic manifestations of multicentric castleman’s disease and possibly reactivated a latent HHV-8 infection. In this case immunohistochemical testing for HHV-8 was not available to prove a role for this agent.

Thickening of the Peritubular Capillary Basement Membrane Is a Useful Diagnostic Marker of Chronic Rejection in Renal Allografts

In kidney transplantation, the multilayering of the peritubular capillary basement membrane (MLPTC) in electron microscopy (EM) has been recognized as a feature of chronic rejection (CR). In this study, thickening of the peritubular capillary (PTC) basement membrane was evaluated by light microscopy (LM) to determine whether it corresponds to the MLPTC in EM and whether it can be used as a diagnostic marker of CR. Forty-eight patients with late renal allograft were divided into chronic allograft nephropathy (CAN) with CR (Group 1, n = 23), CAN without CR (Group 2, n = 19) and CAN-free (Group 3, n = 6). The thickening of the PTC basement membrane (ptcbm) was scored from grades 0 to 2 (ptcbm score), and the MLPTC thickness was measured in EM. Interobserver agreement on ptcbm scores was statistically significant (Kappa coefficient = 0.63). LM and EM lesions corresponded very well. The ptcbm score was highest in Group 1, and ptcbm2 corresponded closely with CR. Group 1 showed significantly thicker MLPTC than Groups 2 and 3. The results validated the usefulness of the ptcbm score and suggested that the thickening of the PTC basement membrane can be a novel diagnostic marker of CR.

Clinical Predictors of Renal Allograft Histopathology: A Comparative Study of Single-Lesion Histology Versus a Composite, Quantitative Scoring System

Progressive injury that is refractory to conventional immunosuppression remains the major hurdle to indefinite survival of transplanted organs. Several clinical risk factors of chronic renal allograft rejection have been identified; although some (e.g., acute rejection) are direct manifestations of immunological injury, others (e.g., donor age) have been more difficult to conceptually link with graft dysfunction. We conducted formal multivariate statistical analyses to reveal associations between established clinical risk factors and allograft histopathology. In a multicenter protocol biopsy-controlled study, 17 clinical risk factors were studied in relation to either the composite Chronic Allograft Damage Index (CADI) score or, to each of eight individual histological indices, using multiple linear regression with forward selection. Nine clinical risk factors were not significantly associated with any histopathological index. Four (donor age, acute rejection, recipient age, and cold ischemia time) were associated both with the total CADI score and, to varying extents, with the individual histopathological indices. In our analysis, clinical risk factors accounted for, at best, only about 60% of the interindividual variation in histopathological score. Our study reveals a missing link between specific clinical risk factors and early histopathological findings that are known to presage accelerated failure of clinically healthy grafts. Given the complex relationship between clinical risk factors, early histopathological changes, and graft outcome, we conclude that composite, quantitative histological indices are best suited to for evaluation of the histological status of the transplant.

Expression of Fractalkine, CX3CR1, and Vascular Endothelial Growth Factor in Human Chronic Renal Allograft Rejection

Aim Fractalkine/CX3CR1 system may contribute to the pathogenesis of renal allograft chronic rejection (CR). Vascular endothelial growth factor (VEGF) is an endothelial mitogen, which shows increased expression in inflammation and vasculopathy. This study sought describe the expression and distribution of Fractalkine/CX3CR1 and VEGF, and their relationship to human renal allograft CR. Methods Renal tissue from 10 patients with CR was examined for Fractalkine/CX3CR1 and VEGF protein by immunohistochemistry for comparison with patients displaying hyperacute rejection ( n = 10), acute rejection ( n = 10), and normal kidneys ( n = 10). All patients were selected based upon histologically proven diagnoses between 1992 and 2003. Results Immunohistochemistry revealed that Fractalkine/CX3CR1 were mostly expressed in the tubulointerstitium and tubular epithelial cell basolateral membrane. Some vessels showed positive staining for Fractalkine/CX3CR1 as well as occasionally glomerular parietal wall cells. Among the CR group, VEGF was mostly expressed in tubular epithelium and the tubulointerstitium. A proportion of glomeruli and vessels had positive staining for VEGF, which was up-regulated most strikingly in the interstitial compartment in CR. There was markedly increased expression of Fractalkine/CX3CR1 and VEGF protein in the interstitium of the CR compared with other groups ( P < .05). VEGF colocalized with the expression of Fractalkine/CX3CR1. Conclusion Fractalkine/CX3CR1 and VEGF may play an important role in the development of interstitial fibrosis via mononuclear cell-induced cytokine production and myofibroblast stimulation in CR. Further studies are necessary to identify the role in the pathogenesis of CR.

Chronic Antibody Mediated Rejection of Renal Allografts: Pathological, Serological and Immunologic Features in Nonhuman Primates

The pathogenesis of late renal allograft loss is heterogeneous and difficult to diagnose. We have analyzed renal allografts in nonhuman primates to determine the relationship between alloantibodies and the graft pathology of late graft loss. Seventeen Cynomolgus monkeys were chosen from among those on several protocols for renal allotransplantation with mixed chimerism induction so that animals with and without alloantibodies were included. All animals received transient CD154 blockade and short-term cyclosporine treatment until day 28. Serial blood samples were tested for alloantibodies. Protocol biopsies and autopsy kidneys were scored for pathology and C4d deposition. Group 1, defined by complete lack of C4d deposition (24 tissue samples; 8 recipients), had no detectable alloantibodies (33 serum samples; 1-7 samples per recipient) and no evidence of chronic rejection. Three survived greater than 2 years with normal function and histology. Group 2, defined as having C4d deposition in peritubular capillaries, all made alloantibodies (100%), and most grafts later showed chronic allograft glomerulopathy (89%), and/or arteriopathy (89%). All grafts in Group 2 failed (3-27 months). Pathologic lesions of typical of chronic rejection in humans develop in monkeys, correlate with antecedent alloantibodies/C4d deposition and predict chronic rejection rather than durable accommodation.

SDF‐1 expression is elevated in chronic human renal allograft rejection

The exact mechanism of acute and chronic allograft rejection still remains unclear. The chemokine SDF-1 as mediator of allograft rejection has been under intensive investigation in liver, cardiac and bone marrow transplantation, whereas in renal transplantation, there are no reports about SDF-1 to date. This study was performed to evaluate if SDF-1 might also play an important role in human renal graft biopsies. One hundred and ninety formalin-fixed, paraffin-embedded renal allograft biopsies were included in the analysis from patients with normal renal graft morphology (according to Banff 97 classification grade 1, n = 84), with acute interstitial rejection (Banff grade 4 type I, n = 10), with acute vascular rejection (Banff grade 4 type II, n = 21), with chronic allograft nephropathy (CAN, Banff grade 5, n = 23), and without rejection but with various other lesions (Banff grade 6, n = 42). SDF-1 was localized by immunohistochemistry. In biopsies with CAN, SDF-1 expression was significantly elevated in interstitial infiltrates and infiltrating neointimal cells of arteries compared with biopsies with normal renal graft morphology. This is the first study describing a role of SDF-1 in human renal allograft rejection. We were able to demonstrate in a large number of biopsies an upregulation of SDF-1 in patients with CAN. Whether SDF-1 has pro-inflammatory or protective properties in this setting has to be evaluated in further trials.

Pathology and pathophysiology of chronic rejection

Purpose of review We summarize and update the histology and pathogenesis of chronic human renal allograft rejection. Particularly, we focus on recent biopsy-controlled clinical studies to prevent the process. Recent findings Chronic rejection is a clinical and a histological diagnosis, defined as ‘gradual deterioration in graft function in the absence of any other disease and with necessary graft histology to confirm the diagnosis’. The histological features may be explained as ‘response to injury’. In a multicenter study patients were initially immunosuppressed with calcineurin inhibitor, mammalian target for rapamycin inhibitor and steroids, and randomized at 3 months to continue with the treatment or have the calcineurin inhibitor withdrawn. The histological chronic allograft damage index score and transplant function were significantly better in the latter group 3 years later. In a single center study, basiliximab, mycophenolate and steroid-treated patients were randomized at transplantation for mammalian target for rapamycin inhibitor or calcineurin inhibitor. The chronic Banff score and transplant function were significantly better in the former group 2 years later. Summary Chronic rejection has been considered irreversible and the pathophysiology is still incompletely known. With proper use of mammalian target for rapamycin inhibitors, however, acting both as immunosuppressive and vasculoprotective compounds, the histological changes and decline in function may be reduced.

Prevention of Chronic Renal Allograft Rejection by SERP-1 Protein

In previous studies we have demonstrated that Serp-1, a myxoma virus encoded serine protease inhibitor, dramatically inhibits neointimal hyperplasia in vascular injury and aortic transplant models. Here we examined the effect of peritransplant Serp-1 administration on chronic renal allograft rejection. Rat renal transplants were performed with sequential recipient sacrifice on postoperative days 2, 10 and 140 to examine both the acute and chronic effects of Serp-1 in recipient rats. Serp-1 administration reduced early posttransplant injury (POD 2) with less acute tubular and vascular necrosis. This translated into a reduction of the characteristic late stage changes of chronic rejection (POD 140), with significantly decreased glomerulosclerosis and neointimal hyperplasia. Effects of Serp-1 treatment were already evident as early as POD 2 with markedly decreased levels of TGF-beta mRNA witnessed at both the early and late time points (POD 2, 10 and 140). We have demonstrated that peritransplant Serp-1 viral protein decreased early injury and allowed reduced chronic rejection in a rat renal model. Recipients treated with Serp-1 are associated with a decrease in TGF-beta mRNA levels in the allografts suggesting that the serine protease inhibitor may inhibit TGF-beta transcription and its profibrotic effects.

Differential regulation of metzincins in experimental chronic renal allograft rejection: Potential markers and novel therapeutic targets

Chronic renal allograft rejection is characterized by alterations in the extracellular matrix compartment and in the proliferation of various cell types. These features are controlled, in part by the metzincin superfamily of metallo-endopeptidases, including matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase (ADAM) and meprin. Therefore, we investigated the regulation of metzincins in the established Fisher to Lewis rat kidney transplant model. Studies were performed using frozen homogenates and paraffin sections of rat kidneys at day 0 (healthy controls) and during periods of chronic rejection at day +60 and day +100 following transplantation. The messenger RNA (mRNA) expression was examined by Affymetrix Rat Expression Array 230A GeneChip and by real-time Taqman polymerase chain reaction analyses. Protein expression was studied by zymography, Western blot analyses, and immunohistology. mRNA levels of MMPs (MMP-2/-11/-12/-14), of their inhibitors (tissue inhibitors of metalloproteinase (TIMP)-1/-2), ADAM-17 and transforming growth factor (TGF)-beta1 significantly increased during chronic renal allograft rejection. MMP-2 activity and immunohistological staining were augmented accordingly. The most important mRNA elevation was observed in the case of MMP-12. As expected, Western blot analyses also demonstrated increased production of MMP-12, MMP-14, and TIMP-2 (in the latter two cases as individual proteins and as complexes). In contrast, mRNA levels of MMP-9/-24 and meprin alpha/beta had decreased. Accordingly, MMP-9 protein levels and meprin alpha/beta synthesis and activity were downregulated significantly. Members of metzincin families (MMP, ADAM, and meprin) and of TIMPs are differentially regulated in chronic renal allograft rejection. Thus, an altered pattern of metzincins may represent novel diagnostic markers and possibly may provide novel targets for future therapeutic interventions.

Immunosuppressive treatment and progression of histologic lesions in kidney allografts

Renal transplantation is the best therapeutic option for patients with end-stage renal disease. Although short-term results are excellent, long-term graft survival has not improved substantially in recent times. Chronic allograft nephropathy (CAN) and death with a functioning graft are the most important causes of graft loss. Recent evidence shows that nephrotoxicity of calcineurin inhibitors contributes to CAN, and the introduction of non-nephrotoxic drugs such as mycophenolate mofetil (MMF) and mammalian target of rapamycin inhibitors may provide new immunosuppressive strategies to improve long-term results after renal transplantation. MMF decreases the risk of developing chronic allograft failure and is useful for treating established CAN, because it has a beneficial effect on allograft fibrosis. Treatment with sirolimus (SRL), a basic immunosuppressive drug given in association with MMF, may offer better renal function, decrease the prevalence of CAN, and downregulate expression of genes responsible for the progression of CAN than treatment with cyclosporine A (CsA). SRL also permits an early elimination of CsA from SRL-CsA-steroid regimens and shows better renal function and improved renal histology without risk of rejection. Notably, this approach improves graft survival at 4 years. Further multicenter studies are needed to determine whether both approaches produce similar results by comparing immunosuppression caused by SRL-based and tacrolimus (TAC)-based treatments. Because TAC is the most commonly used anticalcineurin drug, it is important to compare the effects of steroid-TAC-SRL treatment with and without elimination of TAC. Finally, although caution is needed, the use of non-nephrotoxic immunosuppressive treatment may change the natural history of CAN.

Late Developing C4d-Positive Humoral Renal Allograft Rejection Associated With Withdrawal of Mycophenolate Mofetil

In renal transplantation, C4d-positive acute humoral rejection (AHR) usually develops in the early stage posttransplantation. It is clear C4d can be detected late after the operation, when it is associated with chronic renal allograft rejection. We report a case of a renal allograft recipient who experienced C4d-positive acute renal allograft rejection associated with withdrawal of mycophenolate mofetil (MMF) at 10 months after transplantation. This 21-year-old single male patient received his first cadaveric renal allograft under immunosuppression with cyclosporine, MMF, and prednisolone. The serum creatinine recovered to the normal range within 4 days. A protocol biopsy performed at 1 month after transplantation revealed no signs of rejection. The graft function was stable until 10 months postoperation, when MMF was converted to mizoribin. Three days later a biopsy showed a C4d-positive rejection. Patient had no response to the MMF combined with tacrolimus and steroid bolus therapy, which generally improves 85% of AHR among Chinese. He finally returned to dialysis. Our report suggested that C4d positive AHR may occur late after transplantation. MMF is important to suppress the body’s humoral response to allograft; when MMF was converted to a weaker immunosuppressant, the dose of the other immunosuppressants (cyclosporine for example) must be adjusted properly.

A novel biological assay to detect the active form of TGF-β in urine to monitor renal allograft rejection

Transforming growth factor-beta (TGF-beta) plays an important role in renal fibrosis. Measurement of the concentration of the active form of TGF-beta particularly in urine may help our understanding of the mechanism of chronic allograft nephropathy and could be used as a diagnostic tool. However, TGF-beta release and activation are complex and, consequently, there is currently no accurate way to measure TGF-beta activity. TGF-beta-sensitive BL41 cells were stably transfected with a reporter plasmid harboring a synthetic TGF-beta-inducible DNA sequence upstream from the luciferase gene. Cells were incubated with urine samples from normal donors or transplanted recipients with or without patent nephropathy, and the active form of TGF-beta was determined as luciferase activity. We have established a cell line which expresses luciferase activity in response to active TGF-beta in a dose-dependent manner. Moreover, the use of a histone deacetylase inhibitor greatly increased sensitivity to TGF-beta and also stabilized luciferase inductibility. This test is highly specific to active TGF-beta. Detectable levels of TGF-beta were found in urine from patients with renal dysfunction due to acute or chronic renal allograft rejection (P < 0.001), but not in that from patients with stable, correctly functional kidneys. We describe a highly sensitive and specific assay for active TGF-beta. We also show that, in cases of renal allograft, TGF-beta expression is highly and significantly correlated with acute or chronic rejections.

IL-2–mediated apoptosis of kidney tubular epithelial cells is regulated by the caspase-8 inhibitor c-FLIP

Tubular epithelial cells (TECs) are essential in the maintenance of kidney function. Apoptosis of TECs occur during acute and chronic renal allograft rejection as well as other forms of renal injury, including autoimmune nephritis. The regulation of TEC apoptosis by proinflammatory cytokines associated with renal inflammation [e.g., interleukin (IL)-2 and interferon-gamma (IFN-gamma)] has not been extensively investigated. Apoptosis in murine TECs was determined by FACS with annexin-V or ligation-mediated-polymerase chain reaction (LM-PCR) and mRNA levels by reverse transcription (RT)-PCR or Northern blot. Protein expression was observed using Western blot. IL-2R (CD25) was expressed by murine TECs and up-regulated by IL-2. Both IL-2 and IFN-gamma induced TEC apoptosis and activated caspase-8. Apoptosis with IL-2 was concentration-dependent and blocked by z-IETD-fmk, a specific caspase-8 inhibitor. Apoptosis with IFN-gamma was associated with increased surface expression of Fas, while IL-2 had no effect on Fas. IL-2 did not induce apoptosis in Fas-deficient TECs (M3.1-lpr) suggesting IL-2 regulation of caspase-8 activity requires Fas. Consistent with this, IL-2 but not IFN-gamma was found to decrease mRNA and protein expression of c-FLIP, an endogenous caspase-8 inhibitor in murine TECs. Overexpression of c-FLIP in TECs (CS3.7-FLIP) blocked apoptosis and caspase-8 activation with both IFN-gamma and IL-2. c-FLIP expression was found in kidney cortex, primary and cloned TECs, suggesting c-FLIP is likely a key regulator of caspase-8-mediated apoptosis in vivo. This is the first report of c-FLIP regulation by IL-2 in renal TECs. Augmentation of c-FLIP in TECs may enhance an endogenous mechanism by which TECs normally resist injury to caspase-8-mediated apoptosis and thus may be a useful and novel strategy to prevent tubular injury in transplant rejection and autoimmune nephritis.

Antibodies against mesangial cells in a rat model of chronic renal allograft rejection

Chronic renal allograft rejection (CR) is the leading cause of late renal transplant failure. The histological lesions of CR may comprise glomerular basement membrane (GBM) duplications and mesangiolysis. Its pathogenesis is not yet completely understood, although lately humoral responses have been suggested to be important. Recently, we identified antibody responses directed against GBM antigens in the Fischer (F344) to Lewis (LEW) renal transplantation model. Immunofluorescent studies in this model also suggested deposition of antibodies on mesangial cells. Therefore, we hypothesized that antibodies were not only directed at GBM antigens but also to mesangial cell antigens. F344 to LEW renal transplantations were performed and sera were collected. Pre- and post-transplantation sera were tested for antibody binding to donor rat mesangial cells (RMCs) cultured from F344 kidneys. Anti-mesangial cell antibodies were compared with anti-GBM antibodies measured in the same sera. Post-transplant sera of F344 to LEW renal transplantations, but not LEW to F344, bound to F344 RMC in a dose-dependent manner. Whereas antibodies reactive with RMCs were not present before transplantation, all rats with CR developed antibodies. The antibodies were predominantly of the IgG1 isotype. Antibody binding to RMCs correlated with binding to F344 GBM. Pre-incubation with RMCs partially inhibited GBM binding, and RMC binding was inhibited by GBM. Antibody binding to RMCs did not result in complement activation or cell lysis. LEW recipients of F344 grafts produce antibodies reactive with F344 RMCs. The antigens involved are similar to or at least share antigenic epitopes with antigens recognized in the GBM.

Peritransplant treatment with cobalt protoporphyrin attenuates chronic renal allograft rejection

Allogen-independent injury contributes to chronic rejection in renal allografts and heme oxygenase-1 (HO-1) has been shown to be protective in a number of settings. This study evaluated the effect of renal allograft recipient HO-1 up-regulation on chronic rejection in a rat model. Rat (F344 to Lewis) renal transplantation recipients were grouped: (i) cyclosporine (CsA) alone (0.75 mg/kg s.c. x 10 day; n = 5); (ii) CsA + low dose cobalt protoporphyrin (CoPP) an HO-1 inducer (0.5 mg/kg i.p. on days -5,0,5; n = 13) and (iii) CsA + high dose CoPP (5.0 mg/kg i.p. on days -5,0,5; n = 8). Renal function was assessed by serum creatinine levels on day 140. Histopathologic changes in allografts were graded. Morphometric analyses performed to objectively quantify the vascular changes and glomerulosclerosis. HO-1 expression quantified by Western blot and both HO-1 and endothelin (ET-1) localized using immunohistochemistry. Recipients treated with CsA + high dose CoPP had significantly decreased cortical scarring, vascular hyalinization and intimal thickness. They also had a significant, dose-dependent, reduction in luminal obliteration and glomerulosclerosis by morphometric analyses. This freedom from chronic rejection in recipients treated with CoPP translated into quiescent grafts at postoperative day 140 with immunostaining and Western blot demonstrating decreased level of HO-1 versus controls (P = 0.012). In summary, the peritransplant up-regulation of HO-1 in renal allograft recipients significantly attenuates chronic rejection in rat renal allografts by inhibiting transplant vasculopathy.

PG490-88, a new immunosuppressant, effectively prevents acute and chronic rejection in rat renal allografts

PG490-88 is a semisynthetic derivative of the novel compound PG490 (triptolide) purified from a Chinese herb. It has been shown to prolong acute allograft survival in multiple experimental organ transplant models. However, the effect of PG490-88 on prevention of acute and chronic renal allograft rejection has not been determined. Kidneys of ACI or F344 rats were transplanted into bilaterally nephrectomized LEW recipients as the acute or chronic allograft rejection models, respectively. Treatment of LEW recipients with PG490-88 significantly prolonged ACI kidney graft survival in a dose-dependent manner when compared with the untreated allograft controls. LEW recipients of F344 kidney grafts who received PG490-88 for 90 days with a brief course of low-dose FK506 showed normal serum creatinine levels and markedly reduced histological changes of chronic rejection at day 90 after transplantation. These results suggest that PG490-88 significantly prolongs kidney allograft survival in an acute rejection model and prevents chronic allograft rejection in rats.

Cardiovascular risk profile in patients treated with sirolimus after renal transplantation

Renal transplant patients are inherently predisposed to cardiovascular disease (CVD) as a result of prolonged exposure to multiple cardiovascular risk factors. Approximately one half of all late graft losses are due to death with a functioning graft, and CVD is the most frequent cause of death with a functioning graft among these patients. Immunosuppressive therapies associated with a reduced burden of risk for CVD would therefore greatly decrease post-transplantation morbidity and mortality. The nephrotoxic effects observed with the use of calcineurin inhibitors (CNIs), such as cyclosporine (CsA), run counter to the goal of renal transplant therapy. Sirolimus, a more recent immunosuppressive agent with a unique mechanism of action, offers an alternative to CsA. Recent data from a 4-year study investigating early CsA withdrawal from a sirolimus-CsA-steroid (SRL-CsA-ST) combination demonstrated significantly better renal function, lower blood pressure, and improved graft survival after CsA withdrawal. During that trial, the increase in serum lipids induced by sirolimus was generally manageable with lipid-lowering therapy. Further investigation is warranted to evaluate the value of CNI-free therapy compared with CNI-based regimens in reducing cardiovascular risk factors and improving patient and graft survival.

Effect of posttransplant anti-HLA antibody on outcome of renal transplantation

Pretransplant anti-HLA antibody has an impact on renal transplantation (RT) outcome. However, the role of posttransplant anti-HLA antibody in renal allograft outcome remains unclear. We conducted this study to determine whether posttransplant anti-HLA plays an important role in the outcome of renal allografts. Our investigation used a cross sectional design. Class I and II anti-HLA antibodies were obtained in 41 renal transplant patients. Patients had undergone either living-related (n = 15) or cadaveric (n = 26) RT. All patients had been transplanted for >6 months. The correlation of posttransplant class I and class II, anti-HLA antibodies with renal allograft function glomerular filtration rate (GFR) was analyzed. Patients displaying a GFR of >60 mL/min showed positive anti-HLA antibody status for class I (n = 2) and class II (n = 9). In contrast, those whose renal transplants showed a GFR <60 mL/min included three patients positive for HLA class I and 19 patients for HLA class II. Posttransplant class II anti-HLA antibody showed a negative correlation with GFR ( r = −0.31, P = .03). Preliminary results indicated that class II posttransplant anti-HLA antibody might be one mechanism of chronic renal allograft rejection and may confirm the important role of HLA matching in renal transplantation outcome.

INITIAL SELECTIN BLOCKADE OF T CELL ACTIVATION AND SIGNALLING COMBINED WITH LOW-DOSE SIROLIMUS AND CYCLOSPORINE IMMUNOSUPPRESSION PREVENTS CHRONIC REJECTION OF KIDNEY ALLOGRAFTS

P1141 Aims: We examined the efficacy of recombinant soluble P-selectin glycoprotein ligand (rPSGL-Ig) ± sirolimus (SRL) ± cyclosporine (CsA) in treating the accelerated chronic rejection (CR) of renal allografts from brain dead (BD) F344 donors transplanted into LEW recipients. Methods: rPSGL-Ig (50μg, iv) was administered to the donor 3 hrs after BD and immediately to the host after transplantation to inhibit initial cellular activity. As shown previously, this strategy inhibits T cell activation and signalling. SRL ± CsA was given to immunosuppress subsequent antigen-dependent responses. Grafts from all recipient groups (n=8-12/Gp) were examined histologically at 150 days. Activated CD4+CD25+ T lymphocytes and T cell signalling (signal 1 and 2: TCR/MHC class II and CTLA-4/B7-1/B7/2/CD28) were assessed using double immunostaining. Gene expression of IL-2, IL-10, IFN-γ, TNF-α, TGF-β, and ICAM-1 were measured with RNAse protection assay and Real Time PCR. Recipient groups included: Gp1 = isografts; Gp 2 = BD donor allografts in rats treated with CsA 1mg daily, 10days; Gp 3 = SRL 0.4mg daily 21; Gp4 = SRL (as above) + rPSGLIg (as above); Gp5 = SRL + CsA; Gp6 = SRL + CsA + rPSGL-Ig; Gp7 = SRL 0.1mg, 4-13 days + CsA + rPSGL-Ig. Results: At 150 days after transplantation, Gp1 grafts showed only minor (1/4+) signs of CR (tubular atrophy, interstitial fibrosis, and vascular obliteration). CR of Gp 2 allografts was moderate (2/4+) and extensive in Gp 3 allografts (3/4+). The addition of rPSGL-Ig protected the allografts of Gp 4 hosts substantially (1/4+). Severe tubular injury (4/4+) occurred with high dose SRL+CsA treatment (Gp 5), regardless of rPSGL-Ig (Gp 6). However, grafts of Gp 7 (low dose SRL + CsA + rPSGL-Ig) resembled isografts with inhibited gene expression (IL-2, IFN-γ, and TGF-β), sporadic CD4+CD25+ cells, and signal 1 and 2. Conclusions: Organs from recipients treated with high dose SRL ± CsA showed severe chronic changes, regardless of the effects of rPSGL-Ig on initial T cell activity. In contrast, selectin blockade acts synergistically with low dose SRL plus CsA to prevent CR of renal allografts from BD donors over the long-term.

Natural History of Chronic Humoral Rejection of Renal Allografts in a Non-human Primate1

Natural History of Chronic Humoral Rejection of Renal Allografts in a Non-human Primate1