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.     

The renal medulla in acute renal allograft rejection: comparison with renal cortex

A retrospective cohort study was undertaken to evaluate thediagnostic value of the renal medulla in acute renal allograftrejection (ARAR). One hundred and ninety-five biopsies from98 patients were randomly selected out of 565 transplant biopsies.Biopsies were graded blindly from Grade 0 (no rejection) toGrade 3 (severe rejection) using standard criteria; ARAR wasconfirmed by a fall in all cases of mean serum creatinine concentrationfrom 0.331 ± 0.182 to 0.184 ± 0.079 mmol/l, withanti-rejection therapy. In the 43 biopsies which contained bothcortex and medulla, the ARAR grades and the intensities of mononuclearcell, plasma cell, polymorphonuclear cell and eosinophil infiltrates,and of interstitial oedema and haemorrhage, were similar incortex and medulla (Spearman's Rank Correlation r=0.55–0.81,P < 0.001 ). The sensitivity, specificity and overall accuracyof medullary changes in predicting ARAR changes in the cortexwere 77%, 100% and 38%, respectively. Acute vascular rejectionchanges could not be compared between renal cortex and renalmedulla because of the anatomical differences between cortexand medulla. Further evaluation of ARAR in the all 195 biopsies,of which 188 had cortical tissue and 50 had medullary tissue,showed no significant differences in histological features (P> 0.05), except for more cortical biopsies with plasma cells(29%) than medullary biopsies with plasma cells (10%; P <0.02). It is concluded that: (1) ARAR histological changes aresimilar in cortex and medulla; (2) the predictive value of ARARmedullary changes for cortical rejection changes has low sensitivity(77%) and high specificity (100%). It is suggested that a predominantlynormal medullary renal biopsy in suspected rejection shouldbe repeated to obtain cortical tissue.     

Urine cytology: an underused method to diagnose acute renal allograft rejection

In children, the early detection and accurate diagnosis of acute renal allograft rejection (AR) may be difficult. A delay in the diagnosis and treatment of AR might engender a poor outcome. Core needle biopsy is diagnostic but invasive. However, only a few less-invasive means to diagnose AR are sufficiently accurate to warrant their routine use. One such method is urine cytology. Investigators have demonstrated in more than 800 patients that urine cytology is simple and reliable for diagnosing graft failure. These observations may be important for children, for whom a non-invasive, accurate, and easily repeated indicator of AR may be particularly useful. While not a substitute for transplant biopsy, urine cytology may reduce diagnostic uncertainty and indicate the need for core needle sampling in a timely manner. Received June 4, 1996; received in revised form September 3, 1996; accepted September 12, 1996     

Chronic renal allograft rejection: the significance of non-MHC alloantigens

We studied the role of polymorphic endothelial antigens other than MHC in antibody-mediated chronic renal allograft rejection in two models. In the first model, donor Lewis rat kidneys were transplanted into BN recipients that had been made tolerant for donor class I antigens at the B cell (antibody) level. In this setting Lewis kidney grafts were chronically rejected with stable renal function but increasing proteinuria (> 100 mg/24 h). Rejected graft tissue showed mononuclear cell infiltration and the presence of glomerular vasculonecrotic lesions with fibrinoid material, associated with IgG and IgM deposition, but with absent or weak C3 binding. Graft endothelium showed no expression of MHC class II antigens. Serum antibodies were not reactive with donor class I antigens, but did react with endothelial non-MHC alloantigens. In the second model, more direct information on the role of endothelial non-MHC alloantigens in renal allograft rejection was obtained by transplanting Lewis 1 N kidneys into unmodified BN recipients (MHC-matched transplants). Here, similar to the first model, the animals developed severe proteinuria with stable renal function. Histopathological examination showed mononuclear cell infiltration and deposition of IgM and IgG along the glomerular vasculature, but this time in the presence of strong C3 reactivity. However, glomerular vasculonecrotic lesions with intense fibrin deposition were not observed. The data showed that although clinically the two kidney transplantation models used gave similar chronic rejection phenomena, histopathologically some striking differences were observed in the glomeruli. The precise mechanisms effecting chronic rejection of the grafts is still a puzzle. However, immune reactivity against graft (endothelial) non-MHC antigens may play a significant role.     

尿流式细胞术检测对移植肾急性排斥反应的诊断

目的:探讨尿流式细胞术检测对移植肾急性排斥反应的诊断价值。方法:对63例肾移植术后患者在住院期间出现血肌酐值升高,均行尿流式细胞术检测,结果与临床诊断作对比分析。结果:急性排斥反应患者的尿液细胞数超过10000以上的占97.6%,CD54阳性细胞的占81.8%,CD103阳性细胞占57.6%,HLA-DR阳性细胞占90.9%;在其他患者中,缺少特异性抗原的表达。结论:尿液中HLA-DR、CD54、CD103阳性细胞可作为急性排斥反应的特异标志。尿流式细胞术能区分急性排斥反应与其他因素引起的移植肾功能损伤。尿流式细胞术可作为评价移植肾功能的检测指标。     

重新评估可溶性白介素2受体检测诊断移植肾急性排异的意义

重新评估血、尿sIL-2R水平变化在肾移植中的临床价值。方法 观察108例同种异体肾移植患者血、尿sIL-2R水平,同时作移植肾活检监测肾组织内IL-2R表达阳性细胞。结果 急性排异组血、尿sIL-2R水平均明显高于无排异组、ATN组和CsA肾中毒组,但急性排异组与感染组之间并无显著性差异,临床上仍难以鉴别。急性排异组肾组织内IL-2R表达明显高于无排异组、ATN组、CsA肾中毒组和感染组。结论 (1)血、尿sIL-2R群体水平的变化对急性排异具有诊断价值。但是,单次测定血、尿sIL-2R结果受术后血尿、尿量、感染和肾功能等许多因素的影响;(2)肾组织内IL-2R的表达水平对急性排异的诊断比较可靠。     

Expression of cyclooxygenase-1 and cyclooxygenase-2 in human renal allograft rejection – a prospective study

Cyclooxygenases (COX) are known to be involved in inflammatory kidney diseases. However, there are no data available about the expression of COX-1 and only preliminary reports about the expression of COX-2 in biopsies of patients undergoing acute renal allograft rejection. We conducted this prospective study to analyze the expression, distribution, and cellular localization of COX-1 and -2 and thus to elucidate the role of COX in human kidney transplantation. One hundred forty-four biopsies were included from patients without rejection and unaltered morphology (n = 60), with acute interstitial rejection (n = 7), with acute vascular rejection (n = 21), with chronic allograft nephropathy (n = 16), without rejection but with various other lesions (n = 40). COX-1 and -2 expression was localized in each biopsy by immunohistochemistry. We found a highly significant up-regulation of COX-1 in vessels and in infiltrating interstitial cells of patients with acute allograft rejection compared with biopsies with well-preserved tissue. Also, COX-2 expression was significantly elevated in infiltrating interstitial cells of biopsies with acute rejection. This is the first prospective study demonstrating a significant induction of both COX-1 and -2 in human allograft biopsies with acute rejection after renal transplantation.     

Significance of subclinical rejection in early renal allograft biopsies for chronic allograft dysfunction

To determine the significance of early subclinical rejection of renal allografts, we reviewed 127 biopsy specimens obtained soon after transplantation. Histological finding was categorized according to a modification of the Banff scheme as: acute rejection (AR), borderline changes (BL); non-specific inflammatory changes, (NI) and no rejection (NR). Subclinical rejection was defined as AR, BL or NI. Patients with BL or NI were divided into two groups; one was treated with high-dose methylprednisolone (MP), the other remained untreated. Freedom from chronic allograft dysfunction (defined as non-doubling of serum creatinine 5 yr after transplantation) was significantly more frequent in the NR group (89%) than in the BL (70%) and AR (64%) groups. At 1 yr after transplantation, mean serum creatinine had increased significantly only in the untreated group (p < 0.05), and re-biopsy showed that interstitial fibrosis had developed to a significantly greater extent in the untreated group than in the treated group (p < 0.01). Subclinical rejection in the early protocol biopsies correlated closely with subsequent allograft dysfunction. High-dose MP treatment for early subclinical rejection may be effective in suppressing the development of interstitial fibrosis at 1 yr after transplantation.     

Delayed function reduces renal allograft survival independent of acute rejection

BACKGROUND: Mechanisms by which delayed allograft function reduces renalallograft survival are poorly understood, This study evaluatedthe relationship of delayed allograft function to acute rejectionand long-term survival of cadaveric allografts. METHODS: 338 recipients of cadaveric allografts were followed until death,resumption of dialysis, retransplantation, loss to follow-up,or the study's end, whichever came first. Delayed allograftfunction was defined by dialysis during the first week followingtransplantation, Multivariate Cox proportional hazards survivalanalysis was used to assess the relationship of delayed allograftfunction to rejection and allograft survival. RESULTS: Delayed allograft function, recipient age, preformed reactiveantibody levels, prior kidney transplantation, recipient race,rejection during the first 30 days and rejection subsequentto 30 days following transplantation were predictive of allograftsurvival in multivariate survival models. Delayed allograftfunction was associated with shorter allograft survival afteradjustment for acute rejection and other covariates (relativerate of failure [RR]=1.72 [95% CI, 1.07, 2.76]). The adjustedRR of allograft failure associated with any rejection duringthe first 30 days was 1.99 (1.23, 3.21), and for rejection subsequentto the first 30 days was 3.53 (2.08, 6.00). The impact of delayedallograft function did not change substantially (RR=1.84 [1.15,2.95]) in models not controlling for acute rejection. Theseresults were stable among several subgroups of patients andusing alternative definitions of allograft survival and delayedallograft function. CONCLUSIONS: This study demonstrates that delayed allograft function andacute allograft rejection have important independent and deleteriouseffects on cadaveric allograft survival. These results suggestthat the effect of delayed allograft function is mediated, inpart, through mechanisms not involving acute clinical rejection.     

Expression of nitric oxide and inducible nitric oxide synthase in acute renal allograft rejection in the rat

BACKGROUND: Recent studies have shown that nitric oxide (NO) synthases, particularly inducible nitric oxide synthase (i-NOS), are induced in acute rejection episodes following heart, liver, pancreas and kidney allotransplantation. Furthermore, tissue and cellular injury has been demonstrated to be mediated by peroxynitrite (ONOO-), a metabolite of NO as well as a potent oxidant. However, a detailed relationship between NO, i-NOS and graft injury in transplantation remains elusive. METHODS: The present study used the following models of renal transplantation in rats: allografts (n = 5, Brown-Norway to Lewis [LEW] rats), isografts (n = 5, LEW to LEW) and allografts treated with aminoguanidine (AG), an i-NOS inhibitor (n = 5). Blood urea nitrogen (BUN), serum creatinine (SCr) and urinary and serum nitrosocompounds (NOx) were measured on days 2, 4 and 7 post-transplant. Western blot analysis of i-NOS protein expression and measurement of i-NOS activity were carried out in grafts harvested on Day 7, along with immunohistochemical and histopathological examinations. RESULTS: In the allograft group, both BUN and SCr levels increased markedly on Day 7, in parallel with a sharp increase in NOx. A band stained by anti-i-NOS antibody was detected at approximately 130 kDa, along with high levels of i-NOS activity and diffusely distributed i-NOS-positive cells (macrophages). Histologically, an acute rejection episode was confirmed (Grade 3 according to Banff classifications). In the AG group, reduced renal function and graft injury were significantly less severe than in the allograft group. CONCLUSIONS: In rat renal allograft acute rejection, markedly increased levels of serum NOx were observed, along with enhanced tissue i-NOS activity, together resulting in graft injury. AG administration suppressed the increase of serum NOx levels, with concomitant mitigation of tissue injury and renal function impairment.     

Increase of sTNF receptor levels in acute renal allograft rejection after treatment with OKT3

The use of OKT3 is associated with severe clinical side-effects.Adverse reactions are partly attributed to release of tumournecrosis factor (TNF). TNF binds to two receptors on the outermembranes of most human cell lines. Shedding of these proteins(sTNFR-p55 and sTNFR-p75) may block biological effects of TNF.Here we show a fair correlation between serum levels of sTNFRsand renal function as measured by glomerular filtration rate(GFR). In addition we assessed levels of sTNFR-p55 and sTNFRp75, corrected for reduced renal clearance, in renal allograftrejection and following treatment with OKT3. Corrected serumlevels (CSL) of sTNFR-p55 and sTNFR-p75 were determined in 12renal allograft patients treated for an acute rejection episodewith either OKT3 or methylprednisolone (MPNS). Serum levelsof CSLsTNFR-p55 and CSLsTNFR-p75 in both groups prior to anti-rejectiontreatment were not elevated. CSLsTNFRs peaked at 1 h after theadministration of OKT3, whereas in the MPNS group CSLsTNFRsremained unchanged. We conclude that in acute renal transplantrejection CSLsTNFRs increase after treatment with OKT3. In spiteof high circulating sTNFRs levels all OKT3-treated patientssuffered from clinical side-effects.     

Serial analysis of biomarkers of acute pancreas allograft rejection

Cashion AK, Sabek O, Driscoll C, Gaber L, Tolley E, Gaber AO. Serial analysis of biomarkers of acute pancreas allograft rejection.
Clin Transplant 2010: 24: E214–E222. © 2010 John Wiley & Sons A/S. Abstract: Pancreas transplant recipients experience graft loss in spite of improvements in immunosuppressant therapies and diagnostic technologies. Therefore, a method to improve detection and management of acute rejection is needed. This longitudinal study investigated the usefulness of three biomarkers, granzyme B, perforin, and human leukocyte antigen‐DR alpha (HLA‐DR) measured by real‐time PCR on peripheral blood mononuclear cells, for their ability to detect acute rejection and its resolution in 13 recipients of pancreas allograft. Data demonstrated that pre‐transplant baseline expression of biomarkers decreased following the initiation of immunosuppression. Throughout follow‐up (range 3–27 months), individuals without acute rejection episodes had little variation in their biomarker levels. Recipients with biopsy‐proven rejection had a significant increase in the levels of biomarkers as early as five wk before clinical rejection diagnosis. Furthermore, all seven patients with biopsy‐proven rejection demonstrated a decrease in the levels of granzyme B and perforin following the increased immunosuppression for the treatment of rejection. This is the first clinical serial measurement of biomarkers in recipients of pancreas transplants. The data demonstrate that upregulation of granzyme B, perforin, and HLA‐DR in peripheral blood mononuclear cells are sensitive to changes in the immune environment and could possibly be used to identify those patients at higher risk of rejection.     

Reversal of acute glomerular renal allograft rejection: a possible effect of OKT3

A major cause of renal allograft loss is glomerulovascular rejection. This case report is about an episode of histologically proven acute glomerular rejection that was successfully reversed. Monoclonal antibody OKT3 may have been the effective agent.     

Reversal of acute glomerular renal allograft rejection: a possible effect of OKT3

Abstract. A major cause of renal allograft loss is glomerulovascular rejection. This case report is about an episode of histologically proven acute glomerular rejection that was successfully reversed. Monoclonal antibody OKT3 may have been the effective agent.     

Salvaging of severely ruptured living-related renal allograft secondary to acute antibody mediated rejection

INTRODUCTION

Spontaneous renal allograft rupture (RAR) is a serious and potentially life-threatening complication of kidney transplantation. Debate on the management of RAR has focused on graft nephrectomy versus salvaging in cases where: the allograft rupture site is surgically manageable; the bleeding can be controlled; and/or leaving the renal allograft in situ does not compromise patient survival.

PRESENTATION OF CASE

A 45-year-old, living-related, female, kidney allograft recipient experienced RAR on the fourth day post transplantation. Surgical exploration showed 12 cm laceration along the convex border of the graft. Histologically the graft demonstrated mild acute kidney injury and linear deposition of C4d along the cortical peritubular capillaries; morphological features for violent humoral or cellular rejection were not identified. The graft was surgically salvaged with excellent clinical and biochemical improvement.

DISCUSSION

Observations arising from this case are: (1) RAR caused by rejection is still encountered in clinical practice despite effective immunosuppressive management; (2) the severity of the histopathological features of rejection does not necessarily correlate with the extent of graft rupture; and (3) salvaging the graft should be attempted whenever possible as current immunosuppression and advances in surgical techniques may have an impact on long-term graft function and survival, differing from those previously published.

CONCLUSION

With modern immunosuppression therapy and proven surgical procedures, the efficacy of salvaged renal grafts and graft survival rates may improve substantially.     

Peritubular capillaritis in early renal allograft is associated with the development of chronic rejection and chronic allograft nephropathy

Abstract:  Peritubular capillaritis (PTCitis) has been recognized as one form of acute/active allograft rejection, and its relation to humoral immunity has been suggested. However, its mechanisms remain to be fully clarified, and there are no criteria for evaluating the extent of PTCitis in a biopsied allograft. In this study, we first evaluated the extent of PTCitis in early allografts in patients presenting with acute cellular rejection (ACR) and antibody-mediated rejection (AbAR). We also included patients who showed no evidence of ACR and/or AbAR. Next, we investigated whether or not PTCitis persisted and if peritubular capillary basement membrane (PTCBM) thickening was present in their follow-up biopsy specimens. We adopted the scoring system of PTCitis, which was presented at the Seventh Banff Conference on Allograft Pathology in 2003. In total, 53 patients were included in this study. At first biopsy, 17 showed ACR, eight showed AbAR, 16 showed mild PTCitis only, and 14 were without significant pathologic changes. The PTC score was the highest in the AbAR group, and in some patients the score gradually increased during the follow-up period. Similar changes were also observed in the group with mild PTCitis only. In late allografts, half of the patients with AbAR developed chronic rejection (CR), and the PTCBM score was the highest in that group. Surprisingly, CR was present in more than 30% of patients without ACR and/or AbAR but mild PTCitis only. In the control group, only a few showed CR and/or chronic allograft nephropathy (CAN). In conclusion, it became clear that we should carefully monitor for mild PTCitis in early allografts. In addition, our data also proved the usefulness of the PTC score and PTCBM score.     

Macrophage-derived interleukin-18 in experimental renal allograft rejection.

BACKGROUND: Interleukin 18 (IL-18) is primarily a macrophage-derived, pro-inflammatory cytokine. As macrophages can act as effector cells in acute rejection, we examined the role of IL-18 in a rat model of acute renal allograft rejection. METHODS: Life-sustaining orthotopic DA to Lewis allograft and Lewis-Lewis isograft kidney transplants were performed. In the same model, macrophage-depleted animals, achieved with liposomal-clodronate therapy, were also studied. Macrophage (ED1+) accumulation and IL-18 expression was assessed by immunohistochemistry. CD11b+ cells (macrophages) were isolated from kidney and spleen by micro beads. Real-time PCR was used to assess IL-18 and INF-gamma mRNA expression in tissue and cell isolates. RESULTS: Allografts, but not isografts, developed severe tubulo-interstitial damage and increased serum creatinine by day 5 (P<0.001). Immunohistochemistry revealed a greater ED1+ cell accumulation in day 5 allografts compared with isografts (P<0.001). IL-18 mRNA expression was increased 3-fold in allografts compared to isografts (P<0.001). Accordingly, IL-18 protein was increased in allografts (P<0.001), and was predominantly expressed by ED1+ macrophages. CD11b+ macrophages isolated from allografts had a 6-fold upregulation of IL-18 mRNA expression compared to isograft macrophages (P<0.001). Macrophage depletion resulted in a marked attenuation of allograft rejection, ED1+ and IL-18+ cells were significantly reduced (P<0.05) as was IL-18 mRNA expression (29.28+/-2.85 vs 62.48+/-3.05, P<0.001). INF-gamma mRNA expression (P<0.01) and iNOS (P<0.001) production were also significantly reduced in the macrophage-depleted animals. CONCLUSION: This study demonstrates that IL-18 is significantly increased during acute rejection and is principally produced by intra-graft macrophages. We hypothesize that IL-18 upregulation may be an important macrophage effector mechanism during the acute rejection process.