Mycophenolate Mofetil Dose Reduction in Renal Transplant Recipients: A 5-Year Follow-up Study

Objective

Mycophenolate mofetil (MMF), an immunosuppressant that is widely used in renal transplantation, is associated with several dose-dependent hematologic and gastrointestinal side effects that may require dose reduction or even discontinuation. The aim of this study was to compare renal allograft function and acute rejection episodes among kidney allograft recipients who were on 2 regimens of MMF for at least 5 years.

Materials and Methods

This prospective cohort of 55 kidney allograft recipients was followed for deterioration of allograft function, evidence of acute rejection, and allograft survival. Twenty-two patients (40%) underwent MMF dose reduction to 1.35 to 0.23 g/d due to perceived side effects or economic reasons (group 1). The mean time for this change was 4.2 ± 2.1 months after kidney transplantation. The remaining patients (group 2, n = 33) were continued on MMF (2 g/d). All patients were followed for at least 5 years after transplantation. Renal function tests (blood urea and serum creatinine) were measured monthly for 2 years and then every 2 months. Statistical analysis was performed using SPSS 11.0 (Student t test). P ≤ .05 was considered significant.

Results

The 2 groups were comparable regarding age, gender, and immunosuppressive medications. The renal function tests were comparable at the end of the study. Mean blood urea values were 44.8 ± 5.8 and 46.8 ± 6.8 mg/dL in groups 1 and 2 (P > .05); mean serum creatinine values were 1.32 ± 0.14 and 1.38 ± 0.21 mg/dL, respectively (P > .05). There were 2 graft losses and 1 patient loss in group 2. There were also 2 graft losses among group 1 patients.

Conclusion

Our study showed that MMF dose reduction was not associated with an increased risk of acute renal allograft rejection or impaired allograft function at 5 years.     

Improvement of impaired renal function in heart transplant recipients treated with mycophenolate mofetil and low-dose cyclosporine

BACKGROUND: Cyclosporine (CsA) nephrotoxicity is a common problem after cardiac transplantation. We have studied the impact of CsA dose reduction in association with mycophenolate mofetil (MMF) treatment on renal function in heart transplant recipients with suspected CsA nephrotoxicity (serum creatinine level >2 mg/dl). METHODS: Twelve heart transplant recipients (11 men, 1 woman; 111 to 1813 days after transplantation) with CsA-based immunosuppression (plus azathioprine and/or steroids) and a serum creatinine level >2.0 mg/dl were started on a daily dose of 2000 mg of MMF. Dilated cardiomyopathy was the underlying disease in nine patients, ischemic cardiomyopathy in three patients. Mean patient age was 57 years (range 44-69 years). Azathioprine was discontinued and CsA slowly tapered. Creatinine clearance, serum creatinine level, urea nitrogen, and uric acid were monitored. CsA levels were measured, and CsA dose was adjusted for whole blood levels of 70-120 microg/L. Ten patients still had endomyocardial biopsies, whereas one had echocardiographic controls only. RESULTS: One grade 1B rejection episode according to ISHLT (International Society for Heart and Lung Transplantation) was observed until 1 year after the switch to MMF. One patient was excluded due to gastrointestinal side effects. CONCLUSIONS: Conversion from azathioprine to MMF with consecutive reduction of CsA in heart transplant recipients with CsA-impaired renal function improves renal function as evidenced by lower serum creatinine, urea nitrogen, uric acid, and higher creatinine clearance.     

Clinical experience of mycophenolate mofetil in the treatment of chronic allograft nephropathy in kidney transplantation: three-year follow-up

BACKGROUND: Mycophenolate mofetil (MMF) in conjunction with calcineura antagonists has been shown to prevent acute rejection in renal allograft recipients. Its role in treatment of chronic rejection or allograft nephropathy is still controversial. We initiated the study to investigate the effect of adding MMF to a cyclosporine plus prednisolone regimen in renal recipients with chronic allograft nephropathy. MATERIALS AND METHODS: We retrospectively studied 36 patients with chronic allograft nephropathy, defined clinically as increased of serum creatinine, proteinuria, and hypertension. Renal function, cyclosporine level, renal biopsy, and renal scan were regularly done as indicated. MMF was added to 20 recipients after initial treatment with cyclosporine and prednisolone. The other 16 recipients were managed without adding MMF. Serum creatinine was monitored for 3 years. RESULTS: The demographic characteristics of the patients in the two groups were comparable. The average dose of prednisolone was unchanged throughout the study and the trough level of cyclosporine was maintained in the range of 100 to 150 ng/mL. The serum creatinine decreased initially in the group on MMF, but renal function deteriorated progressively after 6 months. There was a difference in serum creatinine between the two groups but this did not reach statistical significance. CONCLUSION: MMF therapy tender to improve renal function initially but did not attenuate significantly the impairment in chronic allograft nephropathy.     

Prevalence and association of post-renal transplant anemia

In some renal allograft recipients, anemia persists or develops following transplantation. Anemia is associated with pre-operative blood loss and allograft dysfunction, including delayed graft function, acute rejection and chronic allograft dysfunction. To study the prevalence and association of post-renal transplant anemia, we studied 200 renal transplant recipients; 131 (65.5%) patients were males and 69 (34.5%) patients were females, and age ranged from 17 to 67 years, with a mean of 37.7 ± 10.8 years. All patients were receiving cyclosporine, prednisolone and mycophenolate mofetil (MMF). Complete blood count was done at two times: three and six months post-renal transplant. There were 74% anemic patients three months after renal transplantation and 45% anemic patients six months after renal transplantation. High creatinine value, female gender, delayed graft function, episodes of acute rejection, perioperative blood loss and infections were the only significant independent risk factors for prevalence of anemia post-renal transplant. In our study, we did not find an association between MMF and cyclosporine nor angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptors blocker (ARBs) with anemia. This study demonstrates that anemia is a common complication during the first six months after kidney transplantation, with several risk factors precipitating this complication.     

Mycophenolate mofetil dose reduction and the risk of acute rejection after renal transplantation

Mycophenolate mofetil (MMF) significantly decreases acute rejection rates after renal transplantation, but intolerance often occurs, leading to dose reduction. The clinical effect of MMF dose reduction has not been clearly established. This study determined whether MMF dose reduction after renal transplantation was associated with subsequent risk of acute rejection. This retrospective cohort study assessed 213 renal transplant recipients. Cox regression was used to model MMF dose as a time-dependent variable, with time to first acute rejection as the primary outcome. One hundred twenty-six patients (59%) had a total of 176 MMF dose reductions during the study. MMF dose was reduced because of leukopenia (55.1%), gastrointestinal symptoms (22.2%), infection (7.4%), malignancy (1.1%), and unknown reasons (14.2%). The cumulative number of days with the MMF dose reduced below full dose was an independent predictor of acute rejection. The relative risk of rejection increased by 4% for every week that the MMF dose was reduced below full dose. No significant association was observed between the number of days with MMF dropped below full dose and allograft failure. The cumulative number of days with the MMF dose dropped below full dose is a significant predictor of acute rejection after renal transplantation. Clinicians need to be aware of the rejection risk when the MMF dose is reduced and maintain close surveillance on such patients.     

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.     

应用霉酚酸酯联合小剂量环孢素A治疗肾移植术后慢性排斥反应

目的　探讨霉酚酸酯（MMF）联合小剂量环孢素A（CsA）和泼尼松（Pred)治疗肾移植术后慢性排斥反应的临床效果。方法　对临床诊断为慢性排斥反应的8例患者给予MMF1.5～2.0g/d、CsA2～3mg     

A case of acute vascular rejection after overseas deceased kidney transplantation

Abstract:  A 54-yr-old Japanese male received overseas deceased kidney transplantation in January 2006. His allograft functioned immediately and he received immunosuppression with cyclosporine A (CyA), mycophenolate mofetil (MMF), and prednisone (PR). On day 24 after transplantation, he came back to Japan. His serum creatinine level (s-Cr) was 1.39 mg/dL at two months after transplantation when he was admitted into Toda Central General Hospital on March 2006, for follow-up his renal allograft. He had taken only two immunosuppressive drugs, MMF and PR, and had not taken CyA at that time. His serum creatinine gradually rose after hospitalization. Allograft biopsy performed on April 6, 2006, showed acute vascular rejection (Banff 97 acute/active cellular rejection Grade III), together with suspicious for acute humoral rejection (Banff 97 antibody-mediated rejection Grade II). After treatment of two courses of steroid pulses and five d of gusperimus, acute vascular rejection and acute humoral rejection were relieved, which had been proven by the third allograft biopsy. In conclusion, this was a case of acute vascular rejection after overseas deceased kidney transplantation, resulted from non-compliance with immunosuppressive therapy.     

在移植肾功能稳定的受者中主动撤除环孢素A的临床研究

目的 研究在移植肾功能稳定的受者中主动撤除环孢素A(CSA)对急性排斥反应发生率及肾功能的影响.方法 选择35例肾功能稳定的肾移植受者,其中尸体肾移植23例,亲属活体肾移植12例.除2例为再次肾移植外,其余均为初次肾移植.分别在肾移植术后6个月～6年时停用CsA,平均为术后(13.3±9.1)个月.撤除CsA后免疫抑制方案为:霉酚酸酯(MMF)+西罗莫司(SRL)+泼尼松(Pred).撤除CsA前有9例做了移植肾穿刺活检,8例测定了抗HLA抗体.结果 对35例受者随访6个月～4.5年,平均14.8个月.撤除CsA前、后血肌酐平均值分别为(88.1±15.5)μmol/L和(92.3±23.7)/μmol/L(P0.05).撤除CsA后,有2例经活检证实发生急性排斥反应,治疗后均逆转;CsA所致的毒副作用,如牙龈增生、糖耐量异常和多毛症等明显改善.9例移植肾活检中,有3例肾功能正常的受者已出现轻度慢性移植肾肾病表现.抗HLA抗体检测中,7例阴性者在撤除CsA前、后肾功能无明显变化.1例抗HLA抗体呈强阳性者在撤除CsA后进展为慢性移植肾肾病,恢复血液透析.结论 对移植肾功能稳定的受者在移植6个月后撤除CsA,转换为"霉酚酸酯+西罗莫司+泼尼松"的免疫抑制方案是安全的,不增加急性排斥反应风险;撤除CsA有利于消除一些与其相关的毒副作用;对抗HLA抗体呈强阳性者.撤除CsA后很难改变肾功能的进展.     

肾移植患者术后早期应用霉酚酸酯的临床观察

目的 观察肾移植术后早期不同剂量霉酚酸酯（ＭＭＦ）与环孢素Ａ（ＣｓＡ）和泼尼松（Ｐｒｅｄ）联用预防急性排斥反应的效果及安全性。方法 将６４例肾移植患者分为３组,分别给予ＭＭＦ２．０ｇ／ｄ（Ａ组）、１．５ｇ／ｄ（Ｂ组）及Ａｚａ ５０～１００ｍｇ／ｄ（Ｃ组）,每组均联用ＣｓＡ及Ｐｒｅｄ（剂量相同）。观察肾移植术后６个月内急性排斥反应的发生率、移植肾功能及药物的副作用。结果 Ａ、Ｂ、Ｃ组急性排斥反应的发     

Cyclosporine and mycophenolate mofetil 48 hours before renal transplantation enables the use of low cyclosporine doses and achieves better graft function

Reducing calcineurin-inhibitor induced nephrotoxicity and simultaneously avoiding long-term side effects are desirable goals in renal transplantation. We examined the hypothesis that administration of cyclosporine and mycophenolate mofetil (MMF) 48 hours before renal transplantation allows reduction in the target cyclosporine C2 concentration, thus decreasing toxicity and improving graft function. We enrolled 80 kidney recipients in a single-center study comparing 2 cyclosporine-based protocols. Group I patients (n = 40) received a standard dose of cyclosporine (blood cyclosporine C2, 800-1500 ng/mL) with MMF and standard doses of corticosteroids. Group II patients (n = 40) were treated with a low dose of cyclosporine (blood cyclosporine C2, 450-800 ng/mL) and MMF plus low doses of corticosteroids after induction 48 hours before surgery with cyclosporine and MMF. Patient (97.5% vs 100%) and graft survivals (92.5% vs 95%) at 1 year were not different between the groups, although patients in group II experienced significantly fewer acute rejection episodes (10% vs 30%; P < .01). Delayed graft function occurred less often among group I than group II (17.5 vs 20%), but the difference was not significant. Graft function at 1 year was significantly better among group II (serum creatinine 1.31 vs 1.64 mg/dL and creatinine clearance 63 mL/min versus 47 mL/min; P < .05). We concluded that administration of cyclosporine and MMF 48 hours before renal transplantation allowed the safe effective use of low target C2 cyclosporine concentrations, enabling an early decrease in cyclosporine dose. These preliminary results indicated better 1-year graft function compared with the normal cyclosporine dose regimen.     

Elective withdrawal of mycophenolate mofetil in renal transplant recipients treated with mycophenolate mofetil, cyclosporine, and prednisone

In a retrospective study we investigated the risk of acute rejection after the withdrawal of mycophenolate mofetil (MMF) in 39 adult patients treated with cyclosporine (CyA), prednisone, and MMF for at least 6 months following renal transplantation. After reaching a stable renal graft function, MMF was withdrawn and CyA and prednisone were continued. Preceding the withdrawal of MMF, four patients experienced an acute rejection. During a median follow-up of 38 months after discontinuing MMF, no acute rejection occurred. The mean serum creatinine level did not change during the first 6 months after withdrawal of MMF. We conclude that elective withdrawal of MMF in stable renal transplant recipients at 6 months after transplantation bears no important risk of an occurrence of acute rejection. Received: 24 November 1999 Revised: 11 May 2000 Accepted: 18 December 2000     

Withdrawal of mycophenolate mofetil in stable renal transplant recipients

BACKGROUND: Mycophenolate mofetil (MMF) has been demonstrated to decrease episodes of acute rejection in renal transplant recipients during the first year after transplantation. The utility of MMF after 1 year is less clear. METHODS: Forty-five stable renal transplant recipients on maintenance therapy of cyclosporine microemulsion, MMF, and prednisone had MMF withdrawn at approximately 1 year after transplantation. A matching concurrent group of 45 stable renal transplant recipients served as the case control group. RESULTS: Two of 45 patients in the MMF withdrawal group suffered an acute rejection episode as opposed to 1 of 45 in the control group. Both patients who rejected in the withdrawal group had adequate cyclosporine levels and had no recent decrease in prednisone dose. There was no evidence of an increased incidence of proteinuria or increased creatinine levels in the MMF withdrawal group. CONCLUSION: In general, withdrawal of MMF in stable renal transplant recipients is well tolerated. No increased risk of rejection could be demonstrated in this patient group. A larger study will be needed to confirm our result.     

The impact of mycophenolate mofetil dosing patterns on clinical outcome after renal transplantation

BACKGROUND: Mycophenolate mofetil (MMF) has proven to be a very effective drug for the prevention of acute rejection following renal transplantation when dosed as prescribed at 2 or 3 g/d. However, circumstances arise in clinical transplantation where the dose must be lowered, either to avoid drug toxicity or because of concurrent infection. The impact on the incidence of acute rejection and graft survival when the MMF dose must be lowered has not previously been investigated. METHODS: In this study, a cohort of 721 kidney transplant recipients who received immunosuppression using MMF in conjunction with cyclosporine and prednisone and OKT3 (n = 425) or Simulect (n = 296) induction were evaluated. Clinical outcomes were compared and contrasted between patients with and without MMF dose changes within the first year post-transplantation. RESULTS: The majority of patients (70.3%, n = 507) had at least one dose change within the first post-transplant year. Compared with the 214 patients who did not have a dose change, these patients had a much higher incidence of acute rejection within the first post-transplant year (23.3% vs. 3.7%, p < 0.001). This resulted in a significantly decreased 3-yr death-censored graft survival (76.3% vs. 88.3%, p = 0.003). The incidence of acute rejection for patients who had a dose change was highest if the dose change occurred within the first post-transplant month (34.4%). The incidence of acute rejection for the dose change patients was influenced by recipient ethnicity (African-American vs. Caucasian) and the type of induction agent used (OKT3 vs. Simulect). CONCLUSION: Altering the dose of MMF within the first post-transplant year correlated with a significantly worse clinical outcome in this cohort of renal transplant recipients. These data suggest that avoidance of MMF dose changes within the first year after renal transplantation would result in improved graft survival.     

Conversion of liver transplant recipients on cyclosporine with renal impairment to mycophenolate mofetil.

The management of liver transplant recipients with renal function impairment remains controversial because cyclosporine withdrawal from triple immunosuppression regimens may be followed by graft rejection. A nonnephrotoxic and powerful immunosuppressant such as mycophenolate mofetil (MMF) could allow a reduction of cyclosporine dosage or its withdrawal and an improvement in renal function in these patients. Eleven patients with serum creatinine levels greater than 1.5 mg/dL, normal graft function, and a rejection-free period of at least 1 year started MMF at a dose of 2000 mg/d (reduced in case of adverse events) while cyclosporine dosage was slowly reduced. At last follow-up (63 +/- 5 weeks), 7 patients remained free of cyclosporine (6 of those patients are also free of steroids), 2 patients reduced their cyclosporine dose, and 2 patients developed mild acute rejection that responded to a switch to tacrolimus therapy. Serum creatinine and urea levels in the 7 patients free of cyclosporine decreased from 2.22 +/- 0.13 to 1.90 +/- 0.19 mg/dL (P =.05) and 0.95 +/- 0.10 to 0.60 +/- 0.10 g/L (P <.001), respectively. Creatinine clearance increased from 38.16 +/- 5.60 to 47.01 +/- 6. 76 mL/min (P =.005). Control of arterial hypertension also improved. Tolerance to MMF was good, but 6 patients required dose reductions, mainly because of asymptomatic anemia. In conclusion, in liver transplant recipients with stable graft function, MMF may allow cyclosporine dose reduction or discontinuation, thus improving renal function and the control of arterial hypertension. This change of treatment must be carefully monitored because of the frequent need for MMF dose reduction and the risk for rejection.     

Randomized trial of conversion from mycophenolate mofetil to azathioprine 6 months after renal allograft transplantation.

BACKGROUND: In the first year after renal allograft transplantation, triple therapy immunosuppression with cyclosporin (CsA), prednisone (P), and mycophenolate mofetil (MMF) is superior to a triple therapy treatment that includes azathioprine (AZA) instead of MMF. Whether long-term treatment with CsA-P-MMF is better than treatment with CsA-P-AZA is a matter of debate, as 3-year graft survival is similar in MMF- and AZA-treated patients. The purpose of the present study was to examine the short-term effect of changing MMF to AZA in low-risk renal allograft recipients 6 months after transplantation. METHOD: This was a randomized, open-label single-centre study, recruiting 48 low risk renal allograft recipients on CsA-P-MMF therapy 6 months after transplantation, comparing the outcome with continued MMF treatment (2 g b.i.d.) (group A, n=22) or switching MMF to AZA (1 mg/kg) treatment (group B, n=26). RESULTS: The outcome after a 6-months follow-up of patients in group A and group B was similar. Treatment failure rates (defined as clinically diagnosed acute rejection episodes) were 4.5% in group A and 3.8% in group B. There were no patient deaths and no graft failures during the 6-months observation period. Graft function was excellent and similar in both groups. CONCLUSION: Replacing MMF with AZA 6 months after transplantation in low-risk renal allograft recipients is safe and is not associated with altered graft function in the short term.     

A calcineurin inhibitor-sparing regimen with sirolimus, mycophenolate mofetil, and anti-CD25 mAb provides effective immunosuppression in kidney transplant recipients with delayed or impaired graft function

Delayed graft function (DGF) after renal transplantation is a significant risk factor for early acute rejection and graft loss. Sirolimus (SRL) can be administered in the setting of DGF without exacerbating the impaired renal function after transplantation. We examined a calcineurin-sparing regimen using SRL during the early post-operative period in renal transplant patients with delayed or impaired graft function. A retrospective review of 14 consecutive kidney transplant recipients with delayed or impaired graft function who received SRL was performed. The immunosuppressive regimen consisted of daclizumab induction (2 mg/kg), SRL (5-15 mg load followed by 2 5 mg daily maintenance therapy), corticosteroids, and mycophenolate mofetil (MMF, 1.5-3 g/d). Patients were monitored for allograft function, acute rejection, graft survival, thrombocytopenia, and leukopenia. Serum levels of SRL were determined by high-performance liquid chromatography performed at an independent commercial laboratory. Donors were cadaveric in 13 cases and living related in one. The duration of follow-up was 0.5-5.2 months. Nine patients required hemodialysis after transplantation. The mean time to initiation of calcineurin inhibitors was 21 +/- 13 d. Average serum creatinine levels at the initiation of SRL and at 1 month after transplantation were 8.4 +/- 2.7 and 2.1 +/- 1.2 mg/dL, respectively. There were 2 patients (14%) who experienced acute rejection within the first month after transplantation -1 with type I (steroid therapy) and 1 with type II (anti-thymocyte therapy). Serum levels of SRL were initially undetectable in the 2 patients with acute rejection. No grafts were lost during the period of follow-up. Three patients developed thrombocytopenia (platelets < 100 x 10(9)) and no patients developed leukopenia. The combination of SRL with anti-CD25 mAb, MMF, and corticosteroids appears to provide effective non-nephrotoxic immunosuppression for kidney transplantation without the need for a lymphocyte-depleting regimen. However, it is important to monitor serum SRL levels to determine the optimal dosing regimen. Furthermore, long-term follow-up of these patients will be helpful to determine whether improved immunosuppression can be achieved with a fully calcineurin-sparing regimen using SRL.     

Impact of mycophenolate mofetil on recurrent rejection in kidney transplant patients

PURPOSE: Mycophenolate mofetil (MMF) has emerged as a valuable adjunctive agent in renal transplantation. However, due to intolerable adverse effects associated with MMF use in our transplant population, we have used MMF selectively in patients at high risk for recurrent graft rejection, since these patients are known to be at risk for poor long-term graft outcomes. The purpose of this study was to assess the efficacy of MMF in preventing the recurrence of acute rejection following an initial rejection episode in kidney transplant patients in the first year following transplantation. METHODS: Forty-four kidney transplant recipients were given MMF prospectively following treatment of their initial rejection episode to prevent recurrent rejection. MMF 1-2 g/d was given. Doses were adjusted based on tolerance; MMF therapy was to be continued for at least 6 months. The control group consisted of 124 consecutive kidney transplant recipients who had received standard anti-rejection therapy without the addition of MMF. Maintenance immunosuppression consisted predominantly of cyclosporine, prednisone+/-azathioprine. Anti-rejection therapy for both groups consisted of either corticosteroids (methylprednisolone 500 mg i.v. for 3 d or oral prednisone 2 mg/kg/d with rapid taper over 3 wk), OKT3 5 mg/d for 10 d or ATG 15 mg/kg/d for 10 d. All rejection episodes were confirmed by biopsy. RESULTS: The majority of rejection episodes were characterized histologically as mild or moderate. Most patients (76%) received corticosteroids for treatment of their first rejection episode. There was a 68% reduction in the incidence of recurrent rejection episodes within the first year of transplant in patients receiving MMF; only 14% of recipients receiving MMF developed recurrent rejection compared to 44% of patients in the control group (p<0.05). Approximately 50% of patients developed MMF-associated adverse effects (leukopenia, GI toxicity). Only 52% of patients remained on MMF at 6 months. One-yr graft survival was 86% in the MMF group and 89% in the control group (p>0.05). One-year patient survival was 93 and 100%, respectively (p>0.05). CONCLUSIONS: The addition of MMF to maintenance therapy for patients experiencing acute renal allograft rejection may prevent recurrent rejection episodes in the subsequent follow-up year.     

Polyomavirus nephropathy after renal transplantation: a single centre experience

BACKGROUND: Polyomavirus associated nephropathy (PVN) in renal transplant recipients has been observed with increasing frequency recently and has emerged as a cause of allograft failure linked to highly potent new immunosuppressive regimens containing tacrolimus or mycophenolate mofetil (MMF). METHODS: Polyomavirus associated nephropathy was identified in nine out of 182 patients who received renal transplantation between October 1998 and July 2003. PVN was confirmed by allograft biopsy. The clinical records of these nine patients were reviewed, as were all of the allograft biopsies. Electron microscopy was performed in all nine cases. After the diagnosis of PVN, maintenance immunosuppression was reduced. The clinical course and outcome of the PVN patients were reviewed in relation to manipulation of immunosuppressive agents. RESULTS: There were nine cases of PVN in renal transplant recipients and the incidence of PVN was 4.9%. All patients with PVN were under triple immunosuppression comprising tacrolimus and MMF. The mean time to a diagnosis of PVN was 7.8 months after transplantation. Three of the nine patients received antirejection therapy prior to PVN. Seven out of nine PVN patients presenting acute allograft dysfunction were initially treated with high-dose intravenous steroid pulse or OKT3 before reduction of the immunosuppression. After reduction of the immunosuppression, seven patients stabilized their renal function. Two (22%) lost their grafts due to persistent PVN and chronic rejection. Two (22%) patients later developed acute rejection after reduction of the immunosuppression. CONCLUSION: PVN can cause allograft dysfunction and graft loss. Renal allograft recipients who are at risk of PVN should be routinely screened with urine cytology and quantitative measurements of viral load in the blood, particularly patients who had graft dysfunction. Early diagnosis and judicious alteration of immunosuppressive agents might permit a superior prognosis and reduce the graft loss from PVN in renal transplant recipients.     

Safe conversion of mycophenolate mofetil to azathioprine in kidney transplant recipients with sirolimus-based immunosuppression

Aim:   Mycophenolate mofetil (MMF) is a powerful immunosuppressive drug with established efficacy and safety. The long-term use of MMF may bring increased risk of for infection and malignancy and also increased cost of transplantation. The search for minimization of immunosuppressive protocol has led to an open randomized clinical trial of conversion from MMF to azathioprine (AZA).
Methods:   A total of 50 kidney allograft recipients treated with prednisone, sirolimus and MMF were randomized into two groups: converted (AZA group) and continuing (MMF group). The average duration of MMF therapy prior to conversion was 43 months in each group. Inclusion criteria included: patients with serum creatinine levels of less than 200 µmol/L; no past history of acute vascular rejection or recent acute rejection 6 months before randomization; and normal liver function tests.
Results:   Baseline demographics were similar in the two groups. During the 12 month observation period, there were no acute rejection episodes in either group. There were no significant differences in overall patient or graft survival or function. AZA-treated patients had a lower incidence of gastrointestinal complications ( P  = 0.03). Daily cost reduction in the AZA group was more than $US8.79/day per patient.
Conclusion:   In general, replacing MMF with AZA in stable renal transplant recipients is well tolerated and was cost effective with no increased risk of rejection. As the this study was on relatively small samples, larger and longer follow-up studies will be needed to confirm these expected advantages for the long-term outcome and to assess the long-term safety of this minimization of immunosuppressive therapy.