Adhesion molecule polymorphisms in acute renal allograft rejection

Acute rejection is the main cause of early renal allograft failure. Adhesion molecules provide signals for activation and recruitment of effector cells leading to graft infiltration by host T cells, which are key to allograft rejection. This study was undertaken to analyze the adhesion molecule gene polymorphisms in renal transplant recipients and to investigate their potential association with the development of acute allograft rejection. A total of 120 renal transplant recipients and 100 controls were retrospectively genotyped. Seven nucleotide polymorphisms in intracellular adhesion molecule (ICAM)-1, platelet endothelial cell adhesion molecule (PECAM)-1, L-selectin, and E-selectin were analyzed using allele-specific polymerase chain reaction (PCR)-SSP assay and PCR-restriction fragment length polymorphism (RFLP). Recipients were selected on the basis of the development of acute allograft rejection in the first 6 months after renal transplantation. Forty-one patients developed acute allograft rejection and 79 showed uneventful courses. There was no evidence for an association of any polymorphism with acute rejection. Thus, we concluded that these genes do not predispose to acute renal allograft rejection.     

Treatment with the humanized CD154-specific monoclonal antibody, hu5C8, prevents acute rejection of primary skin allografts in nonhuman primates.

BACKGROUND: Allogeneic skin transplantation remains a rigorous test of any immune intervention designed to prevent allograft rejection. To date, no single, clinically available immunosuppressant has been reported to induce long-term primary skin allograft survival in primates. We have previously shown that treatment with the humanized CD154-specific monoclonal antibody, humanized 5C8 (hu5C8), induces long-term renal allograft survival in nonhuman primates. In this study, we evaluated the efficacy of hu5C8 in preventing primary skin allograft rejection in rhesus monkeys. METHODS: Ten rhesus monkeys were transplanted with full-thickness skin allografts mismatched at both class I and class II major histocompatibility loci. Of these, two were given no treatment, five were treated with hu5C8 alone, and three received hu5C8 combined with whole blood donor-specific transfusion (DST). All recipients also received skin autografts for comparison. Animals were followed by inspection, serial biopsy, mixed lymphocyte culture, and alloantibody determination. RESULTS: Treatment with hu5C8 alone or hu5C8 plus DST greatly prolonged allograft survival. Rejection occurred in the untreated group within 7 days. Mean allograft survival in the monotherapy hu5C8 group was >236 days and in the DST group was >202 days; these differences were not significant. Rejection eventually occurred in most animals. Allograft survival was not correlated with the development of T cell hyporesponsiveness in mixed lymphocyte culture. Rejection was not predicted by the development of donor-specific alloantibody. CONCLUSION: These results show that treatment with the CD154-specific monoclonal antibody, hu5C8, greatly delays the onset of acute skin allograft rejection.     

Renal expression of CD44 correlates with acute renal allograft rejection

As CD44 is involved in the activation, proliferation, adhesion, and extravasation of lymphocytes, we hypothesized that CD44 could be involved in the pathogenesis of acute renal allograft rejection. Renal biopsies and plasma were collected from patients suffering an episode of acute renal allograft rejection. CD44 and its ligands, hyaluronic acid (HA) and osteopontin, were analyzed retrospectively by immunohistochemistry and, computer-aided, morphometric analysis. Soluble CD44 (sCD44) and osteopontin in the plasma were determined by enzyme-linked immunosorbent assay. During acute rejection episodes, CD44 and its ligands, HA and osteopontin, were upregulated in the renal allograft. Also, increased sCD44 plasma levels were observed, which correlated with both tubular expression of CD44 and the extent of infiltrate. No differences could be detected between the different pathologic grades of rejection. Upregulation of tubular CD44 and increased levels of circulating sCD44 may reflect a common pathogenic mechanism during acute renal rejection and could be useful markers in the diagnosis of acute renal rejection.     

细胞间粘附分子-1和血管细胞粘附分子-1在慢性排斥反应中的表达

为了探讨移植肾慢性排斥反应的发病机制，应用免疫组化技术（ＡＢＣ法）对１６例肾移植术后发生慢性排斥反应患者的移植肾组织及５例正常肾组织行细胞间粘附分子－１（ＩＣＡＭ－１）、血管细胞粘附分子－１（ＶＣＡＭ－１）染色及ＨＥ染色。结果表明ＩＣＡＭ－１、ＶＣＡＭ－１在正常肾脏和慢性排斥反应移植肾脏上的表达分布不同；结果提示，它们在移植肾慢性排斥反应的发生、发展过程中起重要作用     

Non-invasive monitoring of kidney allograft rejection through IDO metabolism evaluation

The immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) is activated by interferon-gamma (IFN-gamma) and via tryptophan depletion, suppresses adaptive T cell-mediated immunity in inflammation, host immune defense, and maternal tolerance. Its role in solid organ transplantation is still unclear. Therefore, we investigated the usefulness of IDO-mediated tryptophan catabolism in the evaluation of kidney allograft rejection. Blood, urine, and tissue samples were collected from 34 renal transplant patients without rejection and from nine patients with biopsy-confirmed episodes of acute rejection (n=12). Concentrations of kynurenine and tryptophan in serum and urine were analyzed by high-pressure liquid chromatography. Kynurenine to tryptophan ratio (kyn/trp) was calculated to estimate IDO activity. Immunostaining for IDO was performed on renal biopsies. Neopterin was assessed using radioimmunoassay. Kyn/trp and neopterin were detectable at low levels in serum of healthy volunteers and were increased in non-rejecting allograft recipients. Serum levels of kyn/trp were higher in recipients with rejection compared to non-rejectors as early as by day 1 post-surgery. Rejection episodes occurring within 13+/-5.9 days after transplantation were accompanied by elevated kyn/trp in serum (114+/-44.5 micromol/mmol, P=0.001) and urine (126+/-65.9 micromol/mmol, P=0.02) compared to levels during stable graft function. Kyn/trp correlated significantly with neopterin suggesting an IFN-gamma-induced increase in IDO activity. Immunostaining showed upregulation of IDO in rejection biopsies, localized in tubular-epithelial cells. Non-rejected grafts displayed no IDO expression. Acute rejection is associated with simultaneously increased serum and urinary kyn/trp in patients after kidney transplantation. Thus, IDO activity might offer a novel non-invasive means of immunomonitoring of renal allografts.     

Long-term outcome of the use of OKT3 to treat steroid-resistant acute renal allograft rejection

OKT3 was used to treat steroid-resistant acute renal allograft refection in 30 of 496 adult patients transplanted over a 6-year period. Rejection was reversed (defined as a fall in serum creatinine by 50% or more within 30 days of treatment with OKT3) in 40% of cases. Successful reversal was significantly more likely when rejection occurred shortly after transplantation (t ratio-2.53; P=0.019). The long-term outcome was disappointing; the actuarial graft survival at 1 year from the start of treatment with OKT3 was 42%, and no grafts have thus far survived longer than 3 years. Graft survival was horter in older patients (coefficient/standard error 2.226; P<0.05), and no other predictor of long-term outcome was identified. Patient survival at 3 years was 88%. Serious infection occurred in 33% of patients, with two deaths. Our experience suggests that treatment with OKT3 is unlikely to reverse acute renal allograft rejection in more than half of patients where rejection is resistant to steroids. Although long-term graft survival occurred in a few cases, the overall long-term outcome was disappointing, particularly in older patients. Finally, our analysis indicates the difficulty of predicting which patients will derive long-term benefit when OKT3 is used to treat steroidresistant rejection.     

Donor tissue characteristics influence cadaver kidney transplant function and graft survival but not rejection

Acute injury and age are characteristics of transplanted tissue that influence many aspects of the course of a renal allograft. The influence of donor tissue characteristics on outcomes can be analyzed by studying pairing, the extent to which two kidneys retrieved from the same cadaver donor manifest similar outcomes. Pairing studies help to define the relative role of donor-related factors (among pairs) versus non-donor factors (within pairs). This study analyzed graft survival for 220 pairs of cadaveric kidneys for the similarity of parameters reflecting function and rejection. It also examined whether the performance of one kidney was predicted by the course of its "mate," the other kidney from that donor. Parameters reflecting function showed sustained pairing posttransplantation, as did graft survival. In contrast, measures of rejection strongly affected survival but showed no pairing. Surprisingly, the survival of a kidney was predicted by the early performance of its mate, an observation we term the "mate effect." Six-month graft survival and renal function were reduced in grafts for which the mate kidney displayed any criteria for functional impairment (dialysis dependency, low urine output [/= 400 micro mol/L), even for kidneys which themselves lacked those criteria. Rejection measures did not demonstrate the mate effect. In conclusion, kidney transplant function is strongly linked to donor-related factors (age, brain death). In contrast, rejection affects survival and function, but it is not primarily determined by the characteristics of the donor tissue. Graft survival reflects both of these influences.     

Heat shock protein expression in the transplanted human kidney

Heat shock proteins (HSPs) have been shown to represent potential target molecules for T-cell-mediated allograft rejection in heart and kidney transplants. In the present study, we therefore investigated the expression of HSP subtypes 60, 72, and 73 in normal kidneys and qualitative and/or quantitative changes in rejected renal allografts. Six normal kidney tissue specimens, three biopsies from patients with minimal change nephritis, as well as 37 biopsies and eight transplant nephrectomy specimens of patients with renal allograft rejection were studied. Type and severity of rejection were assessed according to the Banff classification. Immunohistochemical demonstration of HSP expression was performed using specific monoclonal antibodies after wet autoclave antigen retrieval on sections from either Carnoy-fixed (biopsies) or formalin-fixed (transplant nephrectomies) and paraffin-embedded tissue. The expression was scored in a semiquantitative manner. All three subtypes were found to be constitutively expressed in normal kidney tissue and in noninflammatory minimal change nephritis, albeit with a characteristic compartmental and cellular distribution. Rejection resulted in a higher immunohistochemical scoring for all three HSP subtypes in compartments in which they were normally present; in addition, a de novo expression of HSP60 was found in the vascular compartment and, moreover, infiltrating mononuclear cells were strongly immunoreactive for HSP60 and HSP73. Only quantitative differences were observed for HSP72 immunoreactivity. These results indicate that rejection episodes are paralleled by an increased but differential expression of HSPs in the glomerular, tubular, and vascular compartments of the kidney. This enhancement as well as the de novo appearance of HSP60 on vascular endothelial cells might explain the presence of HSP-reactive T lymphocytes in rejected allografts.     

Serum levels of macrophage-colony stimulating factor (M-CSF): a marker of kidney allograft rejection.

BACKGROUND: Macrophage-colony stimulating factor (M-CSF) is the principal factor for survival of monocytes and macrophages that play an important role in allograft rejection. We studied M-CSF serum levels during successful renal transplantation and acute graft rejection. METHODS: A total of 114 kidney allograft recipients were assessed for M-CSF levels by enzyme-linked immunosorbent assay (ELISA). RESULTS: M-CSF serum levels were elevated in pre-transplant haemodialysis patients (611+/-355 IU/ml vs 168+/-61 in normal controls, P<0.01). Following successful renal transplantation, M-CSF decreased in the first month, stabilizing at 257+/-222 IU/ml (not significantly different from normal controls) in 52 post-transplant stable patients. There was no correlation between M-CSF level and creatinine clearance. M-CSF levels increased significantly (2-5 times) during biopsy-proven acute rejection episodes in 20 of 25 patients. All rejection episodes were successfully treated and serum M-CSF decreased rapidly to pre-rejection levels in 17/20 patients. In contrast, in five patients with cyclosporin toxicity and four patients with other causes of allograft dysfunction, M-CSF serum levels did not change. CONCLUSIONS: M-CSF serum level might be a specific marker of acute rejection. The source of increased production during rejection warrants further investigation, with infiltrating T cells and resident kidney cells being likely candidates.     

Banff schema for grading liver allograft rejection: utility in clinical practice.

An accurate and functional system for grading acute liver allograft rejection is important for patient management, research, and communication. The Banff schema is a consensus document designed to provide an internationally accepted standard for this purpose. The aim of this study is to determine if application of the Banff schema would significantly alter the grading of acute liver allograft rejection compared with the Birmingham system. One hundred twenty-four post-liver transplantation biopsies performed by the Western Australian Liver Transplantation Service between 1992 and 1997 were retrospectively analyzed by a pathologist and a hepatologist. Each was supplied with a brief clinical history before applying the Banff and Birmingham criteria. Results were compared with each other and to the diagnosis made at the time of the biopsy, which was based on the European grading system. Rejection was diagnosed by the reviewers in 61 of 124 biopsy specimens according to the criteria of Snover. The Banff schema and Birmingham system agreed on the grade of rejection in 22 of the 61 biopsy specimens. The Banff schema elevated the grade of rejection in 39 specimens by an increment of one. In no instance did the Banff schema reduce the grade. Comparison between the Banff schema and diagnosis made at the time of biopsy showed agreement in 39 specimens, whereas the Banff schema elevated the grade in 15 specimens and reduced the grade in 23 specimens. In comparison to the Birmingham system, the Banff schema elevated the grade of liver allograft rejection in the majority of biopsy specimens, and this has the potential to alter clinical management with the adoption of the Banff schema or if the systems are used interchangeably.     

Prospective evaluation of renal allograft dysfunction with 99mtechnetium-diethylenetriaminepentaacetic acid renal scans

A prospective, single-blinded study was done to determine the ability of serial 99mtechnetium-diethylenetriaminepentaacetic acid scans to diagnose renal allograft rejection. Among 28 transplant recipients 111 renal scans were obtained 1 day postoperatively and every 3 to 4 days thereafter for 3 weeks in all patients retaining an allograft. Computer-generated time-activity blood flow curves were analyzed semiquantitatively for the 1) interval between curve peaks of the allograft and iliac artery, 2) renal transit time and 3) renal washout of radionuclide. Excretory function was assessed by degree and interval to appearance of radionuclide in the calices and bladder. Deterioration of renal blood flow and excretion compared to the initial scan was considered rejection. Of 52 scans performed during clinical rejection 47 (90.4 per cent) were interpreted as showing rejection (sensitivity). Of 53 scans interpreted as showing rejection 47 (88.7 per cent) were positive for clinical rejection. The remaining 6 patients (initial false positive results) suffered clinical rejection within 24 to 72 hours. We conclude that 99mtechnetium-diethylenetriaminepentaacetic acid renal scans are useful in the differential diagnosis of renal allograft dysfunction.     

Pathogenesis of chronic renal allograft dysfunction

The pathogenesis of chronic renal allograft dysfunction was reviewed. Chronic rejection/chronic renal allograft nephropathy is the most prevalent cause of renal graft loss after the first year post-transplant. Both immunologic and non-immunologic factors play key roles in the pathogenesis of chronic allograft nephropathy. Acute rejection episodes are the most prevalent risk factor for chronic rejection. Many risk factors for chronic allograft nephropathy have been identified, such as glomerular hyper-filtration, delayed graft function, repeated acute rejection, systemic hypertension and hyperlipidemia. However, the precise pathogenesis of chronic allograft nephropathy remains obscure. The differential diagnosis of immunologically mediated chronic rejection and chronic allograft dysfunction caused by non-immunologic factors is usually impossible using clinical parameters. The histopathologic findings of chronic allograft nephropathy are progressive interstitial fibrosis with tubular atrophy and thickening of vascular intima, and these findings are non-specific. Therefore, the term chronic allograft nephropathy may be clinically preferable to chronic rejection to describe the gradual decline in graft function. The most effective way to prevent chronic allograft dysfunction is to avoid any kind of graft damage via immunologic or non-immunologic pathway.     

FK 506 rescue therapy for intractable liver allograft rejection

Abstract Intractable liver allograft rejection remains an important cause of graft loss. In this Present study, we evaluated the role of oral FK 506 in 30 rejection episodes resistant to conventional cyclosporin-based triple immunosuppression in a series of 28 patients. Rejection was reversed in 11 (91.7%) of 12 patients for intractable acute rejection and in 10 (58.8%) of 17 patients for chronic rejection. A progressive decline in serum bilirubin was observed within 14 days in those successfully salvaged and a serum bilirubin of less than 200 μmol/1 at the time of FK 506 conversion in the chronic rejection subgroup was found to be good predictor of response (specificity 100%, sensitivity 60%). New onset diabetes mellitus (29%) and reversible renal impairment (32%) were the commonest adverse events observed. Eleven (52%) of the responding patients successfully discontinued corticosteroid medication and are currently on FK 506 monotherapy. FK 506 therapy has a significant impact in the control of both intractable acute and chronic allograft rejection with an acceptable toxicity profile.     

The role of plasmapheresis in renal transplantation.

Plasmapheresis has been studied in ten patients who received cadaveric renal allografts. In six patients (group A), plasma was carried out on the first post-operative day and then on alternate days until six treatments had been completed. No beneficial effect was observed but treatment was well tolerated and there were no complications. One patient retains a functioning graft. Plasma exchange was carried out on six consecutive days in five patients (group B) who were actively rejecting their grafts and in whom conventional methods of treatment had failed. All five patients showed improvement in graft function. Rejection was reversed in four patients and was contained in one patient. Subsequently rapid recrudescence of graft rejection occurred in one patient, extended graft survival was seen in two patients, and the other two patients have retained life supporting grafts. Plasmapheresis may have a part to play in the treatment of renal allograft rejection and further evaluation of this treatment is indicated.     

Early diagnosis and treatment of pancreas allograft rejection

A major problem in vascularized pancreas transplantation is the lack of reliable methods for the early diagnosis and effective treatment of allograft rejection. Over a 2-year period, 54 rejection episodes occurred in 31 patients (13 isolated pancreas, 18 simultaneous pancreas-kidney recipients) with pancreaticoduodenocystostomy. A total of 253 radionuclide pancreas examinations were performed (mean 8.4 per patient) utilizing ^99mtechnetium-DTPA. Computer analysis generated a quantitative measure of blood flow to the allograft caused the technetium index (TI). Rejection episodes were characterized as isolated pancreas (22), combined pancreas-kidney (16), or isolated renal (16) allograft rejection in combined engraftments. The majority of rejection episodes occurred early (within 3 months of transplant, N=47) and were more responsive than late rejection to anti-rejection therapy (89.4% vs 42.9%, P=0.01). Mean urinary amylase (UA) levels and TI during normal allograft function were 29,398 U/l and 0.55%, while levels heralding rejection were 6,528 U/l and 0.40%, respectively (P<0.05). The treatment of rejection based upon renal dysfunction or combined renal and pancreas dysfunction resulted in significantly higher graft salvage with a lower incidence of hyperglycemia when compared to isolated pancreas allograft rejection. Of the 11 patients who developed hyperglycemia, 8 (72.7%) ultimately lost their pancreas grafts (P<0.001). Following therapy, a TI above 0.3% was associated with 97.4% graft survival, while levels below 0.3% resulted in a 70% rate of graft loss (P<0.001). Similarly, pancreas allografts with a UA above 10,000 U/l had 91.1% functional survival, while levels below 10,000 U/l resulted in a 66.7% rate of graft loss (P<0.001). Overall, reversal of rejection occurred in 83.3% of cases, with 9 grafts lost due to rejection at a mean of 4.7 months post-transplant. Therapy with ALG or OKT₃ was more effective in reversing allograft rejection than pulsed corticosteroids alone (68.8% vs 47.9%, P=0.05). Patient and pancreas allograft survival is 96.8% and 67.7%, respectively, after a mean follow-up interval of 14.9 months. Monitoring pancreas allograft function by UA, TI, and renal function (in simultaneous transplants) allows for the timely diagnosis and successful treatment of pancreas allograft rejection.     

Circulating immune complexes during various forms of renal allograft rejection episodes

Previous reports on the nephritogenic and immunological enhancing capacity of posttransplant circulating immune complexes (CICs) are conflicting and have been confined to the study of acute rejection episode (AR). This study was undertaken to assess the nephritogenicity of CICs in patients undergoing accelerated acute rejection (AAR) and chronic rejection (CR) episodes.We also assessed the possible role of CICs as mediators of immunological enhancement by assessing CIC levels in long-term-stable allograft recipients. To asses the nephritiogenic role of CICs, 98 CIC determinations were performed on 49 serum samples from 41 pediatric renal transplant recipients using the C1q solid-phase assay (C1q-SPA) and the Raji cell radioimmunoassay (Raji-RIA). Serum samples from normal subjects served as controls. No recipient undergoing AAR had evidence of CICs by eigher assay. 5 of 21 (23.8%) recipients undergoing CR had positive CIC levels in the Raji-RIA, while 4 of 21 (19%) recipients had positive CICs inthe C1q-SPA. There was no statistically significant correlation of CIC levels with long-term allograft function. In addition, there was no evidence supporting antithymocyte globulin as an immunogen in patients demonstrating posttransplant CICs. In summary, CICs do not appear to be an important mediator of AAR or CR episodes, and CICs were not routinely detected in patients with good long-term allograft function.     

Improved renal allograft survival with vitamin D receptor polymorphism

BACKGROUND: Polymorphisms in genes, coding for proteins involved in immune response, or the pathogenesis of atherosclerosis may influence immunological and non-immunological mechanisms that lead to allograft loss. Vitamin D receptor (VDR) agonists reduce allograft rejection in animal models, and there are a number of functional polymorphisms in VDR. METHODS: In all, 379 renal transplant recipients were genotyped for VDR (FokI & ApaI) polymorphisms, and the association of each genotype with renal allograft survival and acute rejection was determined. RESULTS: There was significantly improved allograft survival for patients who were homozygous or heterozygous for the VDR FokI T allele (Hazard Ratio [HR] = 0.488, p < 0.001). CONCLUSION: The association of VDR FokI T allele with improved renal allograft survival is a unique observation. The finding is in keeping with data showing the prevention of chronic allograft rejection with the use of Vitamin D receptor agonists.     

CD103 mRNA levels in urinary cells predict acute rejection of renal allografts

BACKGROUND: CD103 is displayed on the cell surface of alloreactive CD8 cytotoxic T lymphocytes (CTLs) and is a critical component for the intraepithelial homing of T cells. Because intratubular localization of mononuclear cells is a feature of acute cellular rejection of renal allografts, we explored the hypothesis that CD103 messenger (m)RNA levels in urinary cells predict acute rejection. METHODS: We collected 89 urine specimens from 79 recipients of renal allografts. RNA was isolated from the urinary cells, and we measured CD103 mRNA levels and a constitutively expressed 18S ribosomal (r)RNA with the use of real-time quantitative polymerase chain reaction assay. RESULTS: CD103 mRNA levels, but not 18S rRNA levels, were higher in urinary cells from 30 patients with an episode of acute rejection (32 biopsies and 32 urine samples) compared with the levels in 12 patients with other findings on allograft biopsy (12 biopsies and 12 urine samples), 12 patients with biopsy evidence of chronic allograft nephropathy (12 biopsies and 12 urine samples), and 25 patients with stable graft function after renal transplantation (0 biopsies and 33 urine samples) (P = 0.001; one-way analysis of variance). Acute rejection was predicted with a sensitivity of 59% and a specificity of 75% using natural log-transformed value 8.16 CD103 copies per microgram as the cutoff value (P = 0.001). CONCLUSION: CD103 mRNA levels in urinary cells are diagnostic of acute rejection of renal allografts. Because CD103 is a cell surface marker of intratubular CD8 CTLs, a noninvasive assessment of cellular traffic into the allograft may be feasible by the measurement of CD103 mRNA levels in urinary cells.