Gene expression analysis in human renal allograft biopsy samples using high-density oligoarray technology.

BACKGROUND: High-density oligoarray technology is a novel method for screening the expression of thousands of genes in a small tissue sample. Oligoarray analysis of genes expressed during human renal allograft rejection has not been reported previously. METHODS: Seven human renal allograft biopsies with histologic evidence of acute cellular rejection and three renal allograft biopsies without evidence of rejection (control) were analyzed for the expression of 6800 human genes using high-density oligoarrays (GeneChip, Affymetrix, Santa Clara, CA). Quantitative expression of gene transcripts was determined and a comparison analysis between acute rejection and control biopsy samples was performed. Up-regulation of a specific gene transcript during acute rejection was considered to be significant if transcript abundance increased fourfold or more relative to control biopsy samples. RESULTS: Comparison analysis revealed that between 32 and 219 gene transcripts are up-regulated (>fourfold) during acute rejection. Of these transcripts, only four (human monokine induced by interferon-gamma, T-cell receptor active beta-chain protein, interleukin-2 stimulated phosphoprotein, and RING4 (a transporter involved in antigen presentation)) were consistently up-regulated in each acute rejection sample relative to at least two of three control biopsy samples. Six other genes were up-regulated in six of seven acute rejection samples. These were interferon-stimulated growth factor-3, complement factor 3, nicotinamide N-methyltransferase, macrophage inflammatory protein-3beta, myeloid differentiation protein, and CD18. Only two gene transcripts were down-regulated in five of seven acute rejection samples. Significant up-regulation of cytotoxic T-cell effector molecules, previously reported as markers of acute renal rejection in humans, was not detected. CONCLUSIONS: High-density oligoarray technology is useful for screening gene expression in transplanted tissues undergoing acute rejection. Because this method does not rely on a priori knowledge of which genes are involved in acute rejection, it is likely to yield novel insights into the mechanisms and diagnosis of rejection.

Tacrolimus, cyclosporine and plasma lipoproteins in renal transplant recipients.

To compare the effect of tacrolimus (FK506) and cyclosporine (CsA) on plasma lipoproteins in renal transplant recipients receiving maintainance therapy, the following prospective study was undertaken. Blood from nineteen recipients on tacrolimus (FK group) and from twenty-one on CsA (CsA group) was collected at baseline, 3-, 6-, and 10-month intervals. Plasma lipids, lipoproteins and oxidation properties of lipoproteins were determined. Plasma total cholesterol, low density lipoprotein (LDL) cholesterol, and apolipoprotein B (apoB) were substantially increased in both groups, although only the CsA group showed significant differences at all time intervals and at the baseline. High density lipoprotein cholesterol, triglycerides, and apolipoprotein A varied in both groups at time intervals from the baseline, but not significantly. The susceptibility to oxidation of LDL isolated from the FK group at all times was uninfluenced by the tacrolimus treatment, and values were comparable to those obtained from LDL isolated from healthy individuals. A significantly higher susceptibility to oxidation as indicated by the shorter time required to start the formation of conjugated dienes was observed in LDL isolated from the CsA group at 3 and at 6 months of therapy. Tacrolimus-treated patients appear to have less hyperlipidemic and have LDL less susceptible to oxidation than patients treated with CsA.

Payment for immunosuppression after organ transplantation. American Society of Transplantation.

Dramatic improvements in organ transplantation have meant that a growing number of patients must take expensive immunosuppressive medications for the rest of their lives. Currently, Medicare covers most transplantation procedures in the United States, but ends coverage for outpatient immunosuppressive medications after 36 months. Evidence suggests that at least some patients have reduced immunosuppression and their transplants fail because they cannot afford these medication costs. In the years since the advent of effective immunosuppressive therapy, the US Congress has struggled with this issue, and in 1999 temporarily extended medication coverage for eligible patients (based on age and disability) by 8 months. However, a more permanent solution is needed. We advocate that Medicare should cover the cost of all immunosuppressive therapy for all solid organ transplant recipients who cannot afford to pay. A number of potentially cost-effective approaches could be taken, but, in any case, something must be done to ensure that transplants do not fail because recipients cannot pay for immunosuppression.

Prevention of primary cytomegalovirus disease in organ transplant recipients with oral ganciclovir or oral acyclovir prophylaxis.

BACKGROUND: Optimal prophylaxis against cytomegalovirus (CMV) disease for organ transplant patients at risk for primary infection (donor seropositive, recipient seronegative, D+R-) remains to be determined. We hypothesized that prolonged oral ganciclovir therapy following intravenous therapy would provide increased protection. METHODS: A total of 155 evaluable D+R- organ transplant recipients from 13 transplant centers were entered into the study: all received intravenous ganciclovir (5 mg/kg/day) for 5-10 days and then either oral acyclovir (400 mg tid) or oral ganciclovir (1 g tid) for an additional 12 weeks. Patients were assigned to their treatment groups at a central randomization site, with a separate randomization scheme for each of the organs transplanted (kidney, heart, or liver). In the case of kidney transplants, the patients were stratified according to source of the kidney (living related vs. cadaveric donor). The primary endpoint was the incidence of CMV disease in the first six months post-transplant. RESULTS: Treatment with oral ganciclovir was associated with a significant decrease in the incidence of symptomatic disease or viremia when compared with the oral acyclovir group (32% vs. 50%, P<0.05). This difference was most marked in terms of tissue invasive disease: only 3 of 15 symptomatic patients in the ganciclovir group vs. 10 of 21 in the acyclovir group developed tissue-invasive infection (P<0.05). There was a significant difference in the time to CMV disease or viremia in the two groups: mean time 212+/-17 days post-transplant for the acyclovir group vs. 291+/-13 days for the ganciclovir group (P<0.001). The incidence of allograft rejection was 34% in the ganciclovir group and 46% in the acyclovir group (P=NS). Leukopenia was more common in the ganciclovir group (P<0.05), but in no case did it require drug discontinuation. Ganciclovir resistance did not develop in this study. CONCLUSION: Prophylaxis with oral ganciclovir following a brief course of intravenous ganciclovir provides useful protection against primary CMV disease.

The role of tacrolimus in adult kidney transplantation: a review.

The use of tacrolimus (FK506) in adult kidney-transplant recipients has been the subject of a number of single- and multi-center studies. This review article focuses on those studies in which tacrolimus was used either as rescue therapy in patients who developed refractory rejection on cyclosporine (CyA)-based regimens or as primary immunosuppression in adult renal-allograft recipients. Twenty-five prospective and retrospective studies conducted in the US, Japan and Europe, including single- and multi-center experiences, were identified in the medical literature. Of these studies, most show a 74-98% initial success rate for tacrolimus rescue therapy. Comparative studies reviewed herein demonstrate comparable patient- and graft-survival rates between tacrolimus- and CyA-treated patients. Many studies have shown that rejection episodes occur with similar or lower frequency among patients treated with tacrolimus than among those given CyA as primary immunosuppression. The major toxicities associated with tacrolimus are nephrotoxicity, neurotoxicity and diabetogenicity. Results from several studies have also demonstrated an association between these tacrolimus side effects and high whole-blood trough levels of tacrolimus. In many cases, a reduction in dosage can reverse these adverse effects. In summary, based on both single- and multi-center data, tacrolimus has been demonstrated to be efficacious when used for either primary immunosuppression or as rescue therapy for refractory acute rejection in adult renal-allograft recipients.

Assessment of the frequency and costs of posttransplantation hospitalizations in patients receiving tacrolimus versus cyclosporine.

We assessed the frequency and costs of hospitalizations in patients receiving tacrolimus (FK506) compared with patients receiving cyclosporine A for immunosuppression during 1 year after kidney transplantation. Four hundred twelve cadaveric kidney transplant recipients were randomized onto a phase III, prospective, multicenter, clinical trial. Hospital billing data were collected for 1 year posttransplantation. Total inpatient costs were calculated from billed charges and standardized to 1995 US dollars. Medical resource utilization rates and inpatient costs were compared between treatment groups using unpaired Student's t-tests. Complete billing data (transplantation and all posttransplantation hospitalizations) were available for 65% (268 of 412) of the study patients. Among tacrolimus and cyclosporine patients with complete billing data, the rates of allograft rejection were 32% and 47%, respectively (P=0.009), and the rates of rehospitalization during the year after transplantation were 53% and 63%, respectively (P=0.080). The mean per-episode rehospitalization costs were significantly lower among tacrolimus-treated patients compared with cyclosporine-treated patients ($7,495 v $11,497; P=0.031), and the mean total rehospitalization costs were significantly lower in the tacrolimus group compared with the cyclosporine group ($8,550 v $14,869; P=0.029). In addition, the total 1-year hospitalization costs (including transplantation and posttransplantation hospitalizations) were significantly lower in the tacrolimus group compared with the cyclosporine group ($53,435 v $61,191; P=0.046). Compared with cyclosporine-based immunosuppression, tacrolimus-based immunosuppression for kidney transplant recipients was associated with a significantly lower rate of rejection, which was associated with significantly lower per-episode rehospitalization costs, lower total 1-year rehospitalization costs, and lower total 1-year hospitalization costs.

Results of the double-blind, randomized, multicenter, phase III clinical trial of Thymoglobulin versus Atgam in the treatment of acute graft rejection episodes after renal transplantation.

BACKGROUND: Thymoglobulin, a rabbit anti-human thymocyte globulin, was compared with Atgam, a horse anti-human thymocyte globulin for the treatment of acute rejection after renal transplantation. METHODS: A multicenter, double-blind, randomized trial with enrollment stratification based on standardized histology (Banff grading) was conducted. Subjects received 7-14 days of Thymoglobulin (1.5 mg/kg/ day) or Atgam (15 mg/kg/day). The primary end point was rejection reversal (return of serum creatinine level to or below the day 0 baseline value). RESULTS: A total of 163 patients were enrolled at 25 transplant centers in the United States. No differences in demographics or transplant characteristics were noted. Intent-to-treat analysis demonstrated that Thymoglobulin had a higher rejection reversal rate than Atgam (88% versus 76%, P=0.027, primary end point). Day 30 graft survival rates (Thymoglobulin 94% and Atgam 90%, P=0.17), day 30 serum creatinine levels as a percentage of baseline (Thymoglobulin 72% and Atgam 80%; P=0.43), and improvement in posttreatment biopsy results (Thymoglobulin 65% and Atgam 50%; P=0.15) were not statistically different. T-cell depletion was maintained more effectively with Thymoglobulin than Atgam both at the end of therapy (P=0.001) and at day 30 (P=0.016). Recurrent rejection, at 90 days after therapy, occurred less frequently with Thymoglobulin (17%) versus Atgam (36%) (P=0.011). A similar incidence of adverse events, post-therapy infections, and 1-year patient and graft survival rates were observed with both treatments. CONCLUSIONS: Thymoglobulin was found to be superior to Atgam in reversing acute rejection and preventing recurrent rejection after therapy in renal transplant recipients.

Racial differences in renal transplantation after immunosuppression with tacrolimus versus cyclosporine. FK506 Kidney Transplant Study Group.

BACKGROUND: Results of a multicenter, randomized, clinical trial demonstrated that tacrolimus was more effective than cyclosporine in preventing acute rejection in cadaveric renal transplant patients. As African-Americans comprised approximately 25% of the study population, their outcome was analyzed relative to the experience of Caucasian patients. METHODS: Of the 205 patients randomized to tacrolimus, 56 (27.3%) were African-American and 114 (55.6%) were Caucasian. Of the 207 patients randomized to cyclosporine, 48 (23.2%) were African-American and 123 (59.4%) were Caucasian. The efficacy variables were 1-year patient survival, graft survival, and incidence of acute rejection. RESULTS: The incidence of acute rejection was significantly lower in African-American and Caucasian patients treated with tacrolimus than with cyclosporine. Additionally, no African-American patient who was treated with tacrolimus experienced moderate or severe acute rejection, as determined by blinded independent review. The incidence of nephrotoxicity, cardiovascular and gastrointestinal events, malignancies, and opportunistic infections was similar between treatments and race groups. However, there was an increased incidence of posttransplant diabetes mellitus in tacrolimus-treated patients, particularly in African-Americans, and tacrolimus was associated with significantly lower lipid levels in both Caucasians and African-Americans. African-American patients required a 37% mean higher dose of tacrolimus than Caucasian patients to achieve comparable blood concentrations. CONCLUSIONS: Tacrolimus is more effective than cyclosporine in preventing acute rejection in both African-American and Caucasian patients. However, tacrolimus was associated with an increased risk of posttransplant diabetes mellitus, particularly in African-Americans, which was reversible in some patients.

Immunosuppressive therapy in high-risk transplant patients: dose-dependent efficacy of mycophenolate mofetil in African-American renal allograft recipients. U.S. Renal Transplant Mycophenolate Mofetil Study Group.

BACKGROUND: Numerous studies have demonstrated that renal allograft survival is reduced in African-Americans (AAs). This posthoc racial subgroup analysis (AAs vs. non-AAs) tested whether mycophenolate mofetil (MMF) might have favorable implications for the treatment of AA renal allograft recipients. METHODS: Patients received a triple therapy regimen of corticosteroids, cyclosporine, and azathioprine (AZA) 1-2 mg/kg/day, MMF 2 g/day (MMF 2 g), or MMF 3 g/day (MMF 3 g). RESULTS: AAs in the AZA group had the highest biopsy-proven rejection/treatment failure (BPR/TF) rate (57.5% vs. 43.5% for non-AAs). AAs in the MMF 3 g group showed a significant reduction in BPR/TF (57.5% vs. 24.2%, P=0.0008). BPRs were more frequent for AAs in either the AZA (47.5%) or MMF 2 g group (31.8%) than in the MMF 3 g group (12.1%), whereas rejections were reduced for non-AAs receiving either MMF dosage (AZA, 35.5%; MMF 2 g, 15.7%; MMF 3 g, 18.8%). AAs in the AZA group experienced BPR/TF earlier than AAs in the MMF 3 g group (median onset at 64 days vs. > 183 days, P=0.0012). But AAs in the MMF 3 g experienced BPR/TF the latest among the six subgroups of treatment and race. AAs had more severe rejection episodes and higher serum creatinine levels at 6 months after transplant, regardless of treatment group. CONCLUSIONS: Dose-dependent prevention of acute rejection in AAs is best afforded by a dosage of MMF at 3 g/day, whereas 2 g/day provides a superior benefit/risk ratio for non-AAs. MMF at 3 g/day thus provides an improvement over conventional immunosuppressive strategies in reducing the frequency of acute rejections in this immunologically high-risk group.

Drainage of the exocrine pancreas in clinical transplantation: comparison of bladder versus enteric drainage in a consecutive series.

The purpose of this study was to define the incidence of urologic and metabolic complications after simultaneous kidney/pancreas transplantation (SKPT) with bladder drainage (BD). Review of 55 SKPT with BD performed between 1989 and 1995 demonstrated patient, kidney, and pancreas survival rates of 95%, 89%, and 78%, respectively, with a mean follow-up of 41 months (range 12-78 months). Over this follow-up period 78% of these patients experienced a urinary tract infection, 27% had hematuria, and 38% had at least one hospital admission for dehydration. Recent experience with primary enteric drainage of the exocrine secretions of the transplanted pancreas (n = 11) has demonstrated the total absence of these complications (follow-up range 2-12 months). These results suggest the value of continuous re-evaluation of surgical techniques as the care of transplant patients evolve.

Microchimerism and rejection in clinical transplantation.

BACKGROUND: Haemopoietic microchimerism has been identified in recipients of solid-organ transplants and is thought by some to be critical for the development and maintenance of immunological tolerance. The aim of this study was to correlate prospectively the persistence of donor cells with clinical outcome in recipients of kidney, kidney and pancreas, and liver transplants. METHODS: Persistence of donor cells in recipient peripheral blood was assessed at 3 days, and at 1, 3, 6, and 12 months after transplantation by a two-stage nested PCR technique to detect donor MHC HLA DR gene specifically. A pretransplant blood sample was collected from each patient to serve as an individual negative control. Seven liver, six kidney and pancreas, and 17 kidney patients were enrolled. 12 of the 17 kidney patients and all of the kidney and pancreas, and liver recipients were suitable for analysis. Exact matches for donors and recipients at the HLA DR loci (n = 1) or inability to obain primer pair specificity among similar HLA DR types (n = 4), meant that we were unable to analyse five patients. FINDINGS: Donor DNA was detected in 20 (80%) of 25, ten (40%) of 25, seven (30%) of 23, five (22%) of 23, and six (32%) of 19 recipients at 3 days, and 1, 3, 6 and 12 months post-transplant, respectively. Within individuals, the detection of donor DNA varied over time; only two patients had detectable donor DNA at all times. Analysis of the whole group of transplant patients showed a similar frequency and severity of rejection episodes in patients with and without microchimerism as defined by detectable donor DR genes. INTERPRETATION: These data suggest that a significant percentage of the recipients had persistent donor class II DNA in the peripheral circulation for at least 1 year after transplantation. We showed that a pretransplant blood sample is critical to avoid a false-positive result, and suggest that detectable chimerism may vary over time in individual patients. Therefore, analysis of microchimerism with a single, post-transplant analysis may not help in making clinical decisions for individual patients.

An open-label, concentration-ranging trial of FK506 in primary kidney transplantation: a report of the United States Multicenter FK506 Kidney Transplant Group.

This was a multicenter, open-label, concentration-ranging trial of FK506 and cyclosporine in 120 patients undergoing primary cadaveric kidney transplant. Patients were randomized to a cyclosporine-based regimen or to one of three FK506-based regimens designed to achieve low (5-14 ng/ml), medium (15-25 ng/ml), or high (26-40 ng/ml) trough whole blood levels. Corresponding initial doses of FK506 were 0.2, 0.3, and 0.4 mg/kg/day. Patients were evaluated at 42 days after transplant for the occurrence of the first episode of acute rejection or toxicity, necessitating a dosage reduction. There was no significant difference among the three FK506-based regimens and the cyclosporine-based regimen for rejection or toxicity at 42 days. However, the incidence of acute rejection was significantly lower (14% for FK506 and 32% for cyclosporine; P=0.048) for the aggregate of all FK506-treated patients versus cyclosporine. The incidence of neurotoxic and gastrointestinal events was higher among FK506-treated patients during the first month after transplant. A significant trend was observed for increasing toxicity with increasing maximum trough FK506 concentrations (P=0.01) and for decreasing rates of rejection with increasing minimum trough FK506 concentrations (P=0.021). FK506 was effective in preventing early rejection in kidney transplant recipients. The target range of whole blood levels that optimizes efficacy and minimizes toxicity seems to be 5-15 ng/ml. The corresponding recommended initial dose of FK506 for kidney transplant recipients seems to be 0.2 mg/kg/day.

One-year follow-up of an open-label trial of FK506 for primary kidney transplantation. A report of the U.S. Multicenter FK506 Kidney Transplant Group.

Patients undergoing primary cadaveric kidney transplantation were followed for 1 year as part of a phase II, multicenter, open-label concentration-ranging trial of FK506 and cyclosporine. One hundred twenty patients were randomly assigned to a cyclosporine-based regimen or one of three FK506-based regimens designed to achieve low (5-14 ng/ml), medium (15-25 ng/ml), or high (26-40 ng/ml) trough whole blood levels. Corresponding initial doses of FK506 were 0.2, 0.3, or 0.4 mg(kg/day, respectively. Patients with toxicity to FK506 had their target concentration reduced by lowering the dose of FK506. Ninety-two patients completed a 1-year follow-up to determine patient and graft survival and long-term safety. At 1-year, the patient survival rate was 98% for FK506 and 92% for cyclosporine, and the graft survival rate was 93% and 89% in the FK506 and cyclosporine groups, respectively. The incidence of acute rejection was significantly lower (14% FK506, 32% cyclosporine, P=0.048) at day 42 after transplantation. However, the incidence of rejection episodes requiring treatment at 1 year was similar in both groups (33% for FK506 and 32% for cyclosporine). Nephrotoxicity occurred with a similar frequency with FK506 and cyclosporine, but the incidence of neurotoxic events and the incidence of new insulin use were higher among FK506-treated patients. The target range of whole blood levels that optimizes efficacy and minimizes toxicity seems to be 5-15 ng/ml. The corresponding recommended initial dose of FK506 for kidney transplant recipients is 0.2 mg/kg/day. These results indicate that the efficacy and safety of FK506 were comparable to that for cyclosporine for primary immunosuppression in patients undergoing cadaveric kidney transplantation.

Pentoxifylline does not prevent the cytokine-induced first dose reaction following OKT3--a randomized, double-blind placebo-controlled study.

The use of OKT3 as an immunosuppressive agent is accompanied by increased cytokine production and constellation of side effects collectively termed cytokine release syndrome (CRS). Pentoxifylline (PTF) inhibits synthesis of some cytokines, and has been shown to attenuate CRS when administered before OKT3. In this double-blinded, placebo-controlled study, 46 renal allograft recipients were randomized to receive either PTF (800 mg q 8 hr for at least 24 h) p.o. or placebo, along with methylprednisolone (7 mg/kg), diphenhydramine, and acetaminophen, prior to beginning OKT3 as therapy for acute rejection. Patients were observed, and symptoms scored semiquantitatively. Despite the presence of therapeutic PTF levels (721 +/- 726 ng/ml), the frequency and severity of side effects (fever, chills, headache, neurocortical symptoms, dyspnea, nausea, vomiting, diarrhea) did not differ between treatment groups. Likewise PTF did not affect renal function or immunologic response to OKT3, with similar graft and patient survival in both groups. Plasma levels of TNF alpha, IFN gamma, IL-6, and IL-8 increased as predicted following OKT3 administration, without significant differences between PTF and placebo groups. In this controlled, multicenter trial, pretreatment with oral PTF was ineffective in attenuating OKT3-related CRS in renal allograft recipients.

Evolving strategies in immunosuppressive therapy: the Emory experience.

We have reviewed our experience with various immunosuppression regimens over the past 11 years in 2,065 renal transplant recipients. Patients received triple-drug maintenance therapy with CsA, imuran and prednisone following either no induction therapy or treatment with polyclonal (PCA) or monoclonal (MCA) antibody. The most recent immunosuppressive regimen has included CsA, MMF, and prednisone without induction therapy. We observed that those patients receiving PCA had a better graft survival 5 years after transplantation than recipients with MCA induction or those receiving standard triple drug therapy without induction. Patients receiving MMF experienced superior one-year graft survival compared with those receiving induction with PCA, MCA or standard triple drug therapy. A similar one-year graft survival rate for both Black and White recipients was observed in the MMF group and raises the possibility of achieving improved long-term graft survival in Black recipients with a MMF-based immunosuppression strategy. Our experience indicates that excellent short-term graft survival can be achieved with an immunosuppressive protocol of MMF, CsA and prednisone without induction. Graft survival in MMF-treated recipients was equal to or superior to that which we previously achieved with induction therapy.

Preemptive ganciclovir therapy to prevent cytomegalovirus disease in cytomegalovirus antibody-positive renal transplant recipients. A randomized controlled trial.

OBJECTIVE: To determine whether preemptive ganciclovir therapy administered daily during antilymphocyte antibody therapy can prevent cytomegalovirus disease in renal transplant recipients who are positive for cytomegalovirus antibody. DESIGN: Randomized, controlled, multicenter trial. SETTING: 6 university-affiliated transplantation centers. PATIENTS: 113 renal transplant recipients who were positive for cytomegalovirus antibody. INTERVENTION: Patients were randomly assigned to receive either 1) ganciclovir, 2.5 mg/kg body weight administered intravenously on every day that antilymphocyte antibody therapy was administered or 2) no anticytomegalovirus therapy. MEASUREMENTS: Patients were observed for 6 months after completion of antilymphocyte antibody therapy for development of cytomegalovirus disease and cytomegalovirus viremia. RESULTS: Cytomegalovirus disease occurred in 14% of patients (9 of 64) who received preemptive ganciclovir therapy and in 33% of controls (16 of 49) (P = 0.018). Cytomegalovirus was isolated from buffy-coat specimens from 17% of patients (11 of 64) receiving preemptive ganciclovir and from 35% of controls (17 of 49) (P = 0.03). Controlling for the reason (induction or treatment of rejection) for using antilymphocyte antibodies in a Cox proportional hazards model, we found that preemptive ganciclovir still protected against cytomegalovirus disease (adjusted relative risk, 0.27; 95% CI, 0.12 to 0.64). No adverse events were attributed to preemptive ganciclovir therapy during or within 6 months of its administration. CONCLUSIONS: Preemptive ganciclovir therapy administered daily during courses of treatment with antilymphocyte antibodies reduced the excessive occurrence of cytomegalovirus disease in renal transplant recipients who were positive for cytomegalovirus antibody. This approach, which links the most potent immunosuppression to intensive antimicrobial therapy, allows preventive therapy to be given to those patients at greatest risk for developing infectious complications. These patients are likely to benefit most from the preventive strategy.