Sirolimus-associated pulmonary toxicity

BACKGROUND: Pulmonary toxicity has recently been recognized as a potentially serious complication associated with sirolimus therapy. We further detail this condition on the basis of our own cases and those reported in the literature. METHODS: We report three cases of suspected sirolimus-induced pulmonary toxicity that occurred in three renal transplant recipients and searched PubMed for all previously reported cases. RESULTS: Including our current cases, 43 patients with sirolimus-induced pulmonary toxicity have now been reported. Clinical data were incomplete in 28 cases. Analysis of available data for 15 patients revealed that the most commonly presenting symptoms were dyspnea on exertion and dry cough followed by fatigue and fever. Chest radiographs and high-resolution computed tomography scans commonly revealed bilateral patchy or diffuse alveolo-interstitial infiltrates. Bronchoalveolar fluid analysis and lung biopsy in selected case reports revealed several distinct histologic features, including lymphocytic alveolitis, lymphocytic interstitial pneumonitis, bronchoalveolar obliterans organizing pneumonia, focal fibrosis, pulmonary alveolar hemorrhage, or a combination thereof. The diagnosis of sirolimus-associated pulmonary toxicity was made after an exhaustive work-up to exclude infectious causes and other pulmonary disease. Sirolimus discontinuation or dose reduction resulted in clinical and radiologic improvement in all 15 patients within 3 weeks. CONCLUSION: The temporal relationship between sirolimus exposure and onset of pulmonary symptoms in the absence of infectious causes and other alternative pulmonary disease and the associated clinical and radiologic improvement after its cessation suggests a causal relationship. Because the use of sirolimus in organ transplantation has become more widespread, clinicians must remain vigilant to its potential pulmonary complication.     

肾移植后使用西罗莫司继发间质性肺炎七例

目的 分析肾移植术后使用西罗莫司(SRL)的受者继发间质性肺炎的情况,以指导临床治疗。方法 7例肾移植受者在使用SRL后发生间质性肺炎8次,其中2例初始免疫抑制治疗即采用含SRL的方案,5例的初始免疫抑制方案为他克莫司（或环孢素A）+吗替麦考酚酯+泼尼松,后因移植肾肾病（4例）或并发肿瘤（1例）而将他克莫司（或环孢素A）转换为SRL。发生间质性肺炎时,临床表现为发热,伴有呼吸道症状以及呼吸困难,CT和胸片检查有阳性表现。结果 发生间质性肺炎后,4例5次停用SRL,另外3例减少SRL的用量,3～14 d后发热和呼吸道症状逐渐好转,2～4周后胸部影像学检查提示肺炎开始逐渐吸收,而病变完全吸收则需要2～6个月。结论 肾移植后使用SRL可继发间质性肺炎,一旦发生间质性肺炎,应立即减少SRL的用量或停用SRL。     

Pneumonitis associated with sirolimus: clinical characteristics, risk factors and outcome--a single-centre experience and review of the literature.

BACKGROUND: The introduction of sirolimus as an immunosuppressive drug for renal transplantation has lead to an increase of unexplained interstitial pneumonitis. METHODS: Out of a cohort of 115 patients receiving sirolimus for prophylaxis of renal and/or pancreas transplant rejection, 11 patients with interstitial pneumonitis were identified. Medical records and published case series were reviewed to identify risk factors associated with the occurrence of pneumonitis. RESULTS: Eleven out of 80 patients (14%) with late switch to sirolimus developed pneumonitis, in contrast to none of the 35 patients with de novo use of sirolimus. The mean sirolimus trough level at presentation was 16.7 mug/l (range: 6.2-38.7 mug/l). Glomerular filtration rate (GFR) was significantly lower in patients with pneumonitis compared to controls (mean 21.3 +/- 3.9 ml/min vs 38.65 +/- 2.14 ml/min P = 0.002). Two patients needed haemodialysis shortly before pneumonitis was diagnosed. In a multivariate analysis only serum creatinine and GFR were independent predictors for pneumonitis. Sirolimus was discontinuated in five patients and the dose reduced in the other patients. Pneumonitis resolved within 14-28 days in all patients. One patient who had continued low-dose sirolimus treatment relapsed after 5 months, the other five patients had no relapse over a period of 15-48 months. Pooled analysis of our data and other published case series showed that the frequency of pneumonitis in patients with de novo use of sirolimus is significantly lower than in patients with late switch [5/133 (4%) vs 46/326 (14%) patients, P = 0.0024]. CONCLUSIONS: Late switch to sirolimus and impaired renal function are risk factors for pneumonitis. A sirolimus blood trough level above 12 mug/l may increase the risk, but pneumonitis may also occur at blood trough levels as low as 6 mug/l. Since pneumonitis may recur during low-dose sirolimus treatment, discontinuation of sirolimus appears to be the safest treatment option.     

Sirolimus-induced pneumonitis after renal transplantation: a single-center experience

Purpose

Sirolimus is a potent immunosuppressive agent used with increasing frequency in kidney transplantation. However, sirolimus can increase the rate of unexplained interstitial pneumonitis. The aim of this study was to evaluate the clinical characteristics of sirolimus-induced pneumonitis and the therapeutic results in renal transplant recipients.

Patients and methods

Seventy-two patients received sirolimus, conversion or de novo regimen, at our center between January 2007 and April 2011. Twelve of the 72 patients (16.7%) developed interstitial pneumonitis. The patients were divided into three groups according to the following indications of sirolimus use: de novo, early conversion, and late conversion groups.

Results

The mean duration of follow-up was 11.0 ± 11.5 months. The mean blood level of sirolimus measured by microparticulate enzyme immunoassay was 16.5 ± 7.4 ng/mL at the time of diagnosis. The mean time from the start of sirolimus to pneumonitis onset was 14.7 ± 8.0 months. The clinical presentation included fever, cough, dyspnea, general weakness, and periorbital edema. In most cases, radiological imaging tests revealed bilateral lower-lobe involvement. Bronchoalveolar lavage was performed in three patients and two patients showed lymphocytic alveolitis. Sirolimus was discontinued or reduced for the treatment of pneumonitis. All cases of pneumonitis were resolved within 2 to 4 weeks.

Conclusion

Sirolimus blood level should be monitored tightly and early intervention is important when sirolimus-induced pneumonitis is suspected.     

Initial single-center experience with sirolimus after lung transplantation

BACKGROUND: Standard immunosuppression after lung transplantation includes calcineurin inhibitors, mycophenolate mofetil, and steroids. Long-term survivors of lung transplantation are often confronted with chronic kidney disease, by definition related to the intake of calcineurin inhibitors. Sirolimus has been increasingly proposed as an alternative immunosuppressive agent due to its absence of nephrotoxicity, which could be used in selected patients. METHODS: We prospectively administered sirolimus as an alternative to calcineurin inhibitors in 10 lung transplantation recipients with persistent drug nephrotoxicity. They were switched from tacrolimus to sirolimus. Four patients also had bronchiolitis obliterans syndrome. The conversion scheme consisted of an immediate stop of tacrolimus and an 6 to 8-mg loading dose of sirolimus, followed by 4 mg/d. After 5 days, the sirolimus dose was adjusted to maintain trough levels between 12 and 18 ng/mL or 6 and 12 ng/mL for combined sirolimus and tacrolimus. Patients were monitored for renal and graft function as well as clinical status. RESULTS: A significant decrease in creatinine was observed after 1 week of treatment (P = .011). Azotemia decreased after 1 month, remaining stable (P < .01). Pulmonary function tests did not show significant modification from before sirolimus, inception in patients with or without bronchiolitis obliterans syndrome. There were seven infections. One patient died of complications related to bronchiolitis obliterans. CONCLUSION: Sirolimus was a useful alternative immunosuppressant, allowing significant tacrolimus withdrawal in transplant recipients with renal impairment. Sirolimus administration allowed recovery of renal function with low morbidity; it was useful for rescue of chronic renal impairment after lung transplantation.     

Sirolimus-associated diffuse alveolar hemorrhage in a renal transplant recipient on long-term anticoagulation

Sirolimus (rapamycin, rapamune) is an effective immunosuppressant that has been widely used in solid organ transplantation. Recently, two disconcerting side effects, namely pulmonary toxicity, usually in the form of interstitial pneumonitis, and the onset of nephrotic range proteinuria, have been recognized. We report the case of a renal transplant recipient who had been on chronic anticoagulation therapy for a mechanical aortic valve, and who developed pulmonary distress necessitating emergent intubation 18 days after starting sirolimus therapy. Open lung biopsy showed diffuse alveolar hemorrhage with fibrin deposits in the alveolar spaces and small bronchi. Urine protein/creatinine ratio at that time was 16.7. Upon discontinuation of sirolimus, alveolar hemorrhage and nephrotic range proteinuria resolved. We suggest that extra vigilance be paid in individuals who are on chronic anticoagulation and who are started on sirolimus.     

An unusual presentation of sirolimus associated cough in a renal transplant recipient

Sirolimus-associated pulmonary problems are rare but life threatening. Pulmonary problems due to sirolimus treatment are interstitial pneumonitis, bronchiolitis obliterans organizing pneumonia (BOOP), and alveolar hemorrhage. We present a case of sirolimus-related cough in the absence of any pulmonary radiological findings. A 55-year-old man with a history of 4 years of hemodialysis therapy because of end-stage renal disease of unknown etiology underwent cadaveric renal transplantation in June 2006. Three days following the initiation of sirolimus therapy he complained of dry cough and fever. There were no clinical or laboratory findings compatible with specific pulmonary disease. After switching sirolimus to tacrolimus, the cough improved within 1-2 days and resolved in 5 days. Sirolimus should be considered in the differential diagnosis of pulmonary problems in the early posttransplantation period even in the absence of radiological findings.     

Proteinuria Developing After Clinical Islet Transplantation Resolves with Sirolimus Withdrawal and Increased Tacrolimus Dosing

Sirolimus is a potent immunosuppressant, which may permit the avoidance of nephrotoxic calcineurin inhibitors (CNI). However, cases of proteinuria associated with sirolimus have been reported following renal transplantation. Here, we report three cases of proteinuria (1, 2 and 7 g/day) developing during therapy with sirolimus plus low-dose tacrolimus following clinical islet transplantation (CIT) in type I diabetic subjects. The proteinuria resolved after discontinuation of sirolimus, substituted by mycophenolate mofetil (MMF) combined with an increased dose of tacrolimus. A renal biopsy in one case indicated only the presence of diabetic glomerulopathy. Five other CIT recipients developed microalbuminuria while on sirolimus which all resolved after switching to tacrolimus and MMF. The resolution of proteinuria from the native kidneys of CIT recipients after the discontinuation sirolimus suggests that, at least in some individuals, sirolimus itself may have adverse renal effects. Sirolimus should be used cautiously with close monitoring for proteinuria or renal dysfunction.     

Sirolimus conversion experience in a single center

OBJECTIVE: One major cause of graft loss is chronic allograft nephropathy (CAN), which may relate to calcineurin inhibitors (CNIs). We converted CAN cases from CNIs to sirolimus and observed the outcomes. METHOD: From January 2004 to August 2007, there were 28 kidney recipients in our center with creeping creatinine levels compatible with CAN. We started sirolimus at 2 mg/d and reduced the CNIs gradually. Sirolimus trough levels were kept between 5 and 8 ng/mL. Mycophenolic acid was cut in half; there was no adjustment on prednisolone dose. RESULTS: The mean switch time was 47.3 months after transplantation. One case discontinued sirolimus due to severe drug-induced pneumonitis. Twelve of the 27 (45%) patients showed improvements in graft function. The most frequent complications were anemia (13/28), hyperlipidemia (13/28), and pneumonitis (4/28). A baseline serum creatinine level less than 2.2 mg/dL seemed to forecast a response to sirolimus conversion. Most of the graft functional improvement occurred within 6 months after the switch. No graft or patient loss was encountered. CONCLUSION: Our experience suggested that 45% of patients with sirolimus conversion showed improved graft function. Among patients within 1 year after transplantation, those with a creatinine level less than 2.2 mg/dL, no proteinuria, and no hyperlipidemia seemed to be better candidates for Sirolimus conversion.     

Interstitial pneumonitis associated with sirolimus in liver transplantation: a case report

Sirolimus is a powerful immunosuppressive drug initially used in kidney transplant patients but now increasingly employed in recipients of other types of solid organ transplants, such as liver, heart, lung, or pancreas. Sirolimus is indicated for rescue therapy and to reduce the toxic side effects of calcineurin inhibitors. However, its use has been associated with an uncommon but important pulmonary toxicity. Reports have described interstitial pneumonitis, bronchiolitis obliterans, organizing pneumonia, and alveolar proteinosis. We present the case of a liver transplant patient with interstitial pneumonitis associated with sirolimus.     

Sirolimus-associated acute respiratory distress syndrome in a renal transplant recipient

Sirolimus is a new potent immunosuppressive drug used in organ transplantation; its major advantage is the absence of deterioration in renal function. Documented adverse effects include myelosuppression and hyperlipidemia. Recently several cases of sirolimus-associated interstitial pneumonitis have been reported, usually of mild severity. We report a new case that was complicated by a severe acute respiratory distress syndrome, which required several days of mechanical ventilation. No infectious or cardiogenic etiology was documented. Low sirolimus blood levels and acute CD4 lymphocytic alveolitis suggested an immune-related mechanism rather than a direct toxic effect of the drug. The patient recovered after discontinuation of sirolimus and the administration of corticosteroids.     

Bronchoalveolar lavage cell profile in methotrexate induced pneumonitis

BACKGROUND: Pneumonitis is a rare but potentially life threatening side effect of methotrexate treatment for rheumatoid arthritis which needs to be distinguished from interstitial lung disease due to rheumatoid arthritis. METHODS: To examine the value of bronchoalveolar lavage (BAL) in diagnosing methotrexate pneumonitis, the BAL cell profile of four patients with methotrexate pneumonitis was compared with findings in 16 patients with rheumatoid arthritis treated with methotrexate without clinical or radiological evidence of lung disease and eight patients with interstitial lung disease secondary to rheumatoid arthritis treated with methotrexate. RESULTS: Methotrexate pneumonitis was associated with an increase in the lymphocytes in the BAL fluid to 33-68% of total BAL cells. BAL lymphocytosis was also found in five patients in each of the two control groups. The four patients with methotrexate pneumonitis had a disproportionate increase in CD4+ cells to 72-84% of total lymphocytes and in the CD4/CD8 ratio to 17.0, 6.6, 8.7, and 4.0, respectively, figures which exceeded those of the two control groups. CONCLUSIONS: Methotrexate pneumonitis was associated with lymphocytic alveolitis with a preferential increase in CD4+ cells. This pattern differs from that in interstitial lung disease due to rheumatoid arthritis and may therefore assist in making an early diagnosis of methotrexate pneumonitis.


     

Four cases of sirolimus-associated interstitial pneumonitis: identification of risk factors

Sirolimus-associated interstitial pneumonitis is a severe side effect of sirolimus therapy; fatal outcomes have been described. We report 4 patients with sirolimus-associated interstitial pneumonitis and review the literature for risk factors for the development of disease. Until June 2005, 48 patients received either de novo sirolimus treatment (n = 7) or were switched from a calcineurin inhibitor-containing regimen to a sirolimus-based protocol for various indications (n = 41). Compared with the 44 patients on sirolimus therapy with no evidence of a disorder, the 4 patients (8.3%) who developed suspected sirolimus-associated interstitial pneumonitis showed no difference in gender, immunosuppressive therapy, days posttransplantation, comorbidity, or preexistent lung disease. Several points, however, are of interest. None of the de novo-treated patients except 4 patients (9.8%) with late administration of sirolimus developed interstitial pneumonitis. The 4 patients with interstitial pneumonitis tended to be older (58.7 +/- 5.5 vs 46.9 +/- 1.7 years) and received higher sirolimus doses (3.5 +/- 0.5 vs 1.4 +/- 0.2 mg/d) with greater trough levels (15.4 +/- 2.9 vs 8.0 +/- 1.2 micro g/L) at the onset of symptoms. Most notably, all patients with interstitial pneumonitis had a loading dose at the start of therapy, and an increase in sirolimus dose (or trough level) within 3 weeks prior to the onset of symptoms. Additional potential risk factors identified from the literature include allograft dysfunction, hypervolemia, and male gender. With careful monitoring (or even exclusion from therapy) of patients at risk for the development of disease, we have had no case of sirolimus-associated interstitial pneumonitis since September 2004.     

Sirolimus immunosuppression in pediatric heart transplant recipients: a single-center experience.

BACKGROUND: Sirolimus has been used in heart transplant recipients for treatment of rejection, alternative immunosuppression (IS) and promotion of regression and prevention of graft vasculopathy (coronary artery disease [CAD]). This study reports on our center's experience with 16 children who underwent heart transplantation. METHODS: Data were obtained by retrospective review. RESULTS: Median age at time of review was 12.3 years (n = 16, 5.1 to 18.0 years; 9 boys, 7 girls), and at time of transplant 7.5 years (6 months to 18.0 years). Median time of sirolimus introduction was 2.7 years (1 month to 8.2 years) post-transplant. Fifteen patients were on steroids, 10 on tacrolimus (FK) and mycophenolate mofetil (MMF), 5 on FK and 1 on MMF with no calcineurin inhibitors (CNIs). The average dose of sirolimus was 0.25 mg/kg or 7.0 mg/m(2) to maintain a target level of 5 to 15 mug/liter. Sirolimus was started for CAD in 6 patients (38%), rejection in 5 (31%), and in 5 with combinations of CNI intolerance, CAD, renal dysfunction and rejection. All 6 who received sirolimus for rejection (International Society for Heart and Lung Transplantation [ISHLT] Grade 3A) showed improvement on follow-up biopsies. Two of 3 who received sirolimus for renal dysfunction showed improvement (glomerular filtration rate [GFR] 43 to 67 and 32 to 106 ml/min per 1.73 m(2), respectively). Side effects included hyperlipidemia (38%), abdominal pain (31%), mouth ulcers (26%), anemia or neutropenia (12.5%), persistent pericardial effusion (6%) and interstitial lung disease (6%). Sirolimus therapy was discontinued in 3 patients due to side effects. CONCLUSIONS: In this study sirolimus was found to be a valuable IS agent for the management of rejection, significant renal dysfunction and CNI side effects. These results support the need for prospective studies of the role of sirolimus in primary rejection prophylaxis, primary CAD prophylaxis and CAD regression. There also exists a need to establish an adverse event profile for this drug.     

Renoprotective effects of sirolimus in non-immune initiated focal segmental glomerulosclerosis.

BACKGROUND: In this study we tested the hypothesis that sirolimus (a target of rapamycin inhibitor that attenuates intrinsic renal and immune cell proliferation) reduces glomerular hypertrophy and tubular epithelial cell (TEC) proliferation, and attenuates the progression of renal scarring and dysfunction, in a non-immune initiated model of focal segmental glomerulosclerosis (FSGS). METHODS: Adult male Wistar rats with adriamycin nephropathy (AN) were stratified into two groups, according to proteinuria on day 12, and received either vehicle (dimethylsulphoxide) or sirolimus (0.1 mg/kg) by daily subcutaneous injection, from day 14 until day 49 (n = 8 each). Control animals were also examined (n = 3 each). RESULTS: Sirolimus did not affect the progression of proteinuria, renal dysfunction, hypercholesterolaemia, body weight or alter intraluminal cast formation in AN. Sirolimus prevented the increase in kidney enlargement in AN, and attenuated glomerular capillary tuft expansion, glomerulosclerosis and periglomerular myofibroblast accumulation. In the tubulointerstitium, sirolimus attenuated tubular dilatation, TEC proliferation and interstitial fibrosis. This was accompanied by a reduction in renal cortical TGF-beta1, but peritubular myofibroblast accumulation and renal inflammation (glomerular and interstitial ED-1 and CD3-positive cell accumulation), were unaffected. CONCLUSION: The anti-renotrophic properties of sirolimus were correlated with a reduction in renal scarring in AN. These data suggest that sirolimus has renoprotective effects when administered during the early stages of an FSGS pattern of chronic renal injury.     

Use of sirolimus and low-dose calcineurin inhibitor in lung transplant recipients with renal impairment: results of a controlled pilot study

BACKGROUND: Renal failure induced by calcineurin-inhibitor agents is a common complication of lung transplantation. Sirolimus, a macrolide immunosuppressant with a distinct mechanism of action, may prevent renal failure but was found to have a high infectious and toxicity rate in the only relevant study conducted so far. The aim of the present prospective pilot study was to assess the benefit of sirolimus combined with low-dose calcineurin inhibitors in this patient population. METHODS: Sixteen lung transplant recipients with post-transplantation renal dysfunction were allocated to receive the standard immunosuppression regimen or a combination sirolimus/low-dose calcineurin-inhibitor regimen. Target trough levels of sirolimus were 4 to 8 ng/mL. Tacrolimus was tapered down to target trough levels of 4 to 8 ng/mL and cyclosporine to 80 to 120 ng/mL. Duration of follow-up was 18 months. RESULTS: At the end of follow-up, the sirolimus group showed a significant improvement in creatinine clearance (42.6 mL/min vs. 32.5 mL/min, P= 0.05), whereas the control group showed a significant reduction (32.3 mL/min vs. 40.3 mL/min, P= 0.02). The difference between the groups was statistically significant (P < 0.0001). Acute rejection episodes occurred in 2 patients in the sirolimus group and 1 patient in the control group (P= NS). Pneumonia developed in 6 study patients and 4 controls; all responded to antibiotics. CONCLUSION: Sirolimus combined with low-dose calcineurin inhibitors appears to be a safe and effective alternative immunosuppressive therapy to sirolimus alone in lung transplant recipients with renal failure. Graft function is preserved, and infection and drug toxicity rates are low.     

Initial experience with sirolimus and mycophenolate mofetil for renal rescue from cyclosporine nephrotoxicity after heart transplantation

Calcineurin inhibitors (CNIs) have become the cornerstone of immunosuppressive regimens following heart transplantation, but their use is associated with nephrotoxicity. We evaluated a CNI elimination protocol in 14 patients with renal impairment at 48.3 +/- 36.0 months after heart transplantation. The mean serum creatinine was 321 +/- 107 micromol/L; cyclosporine (n=13) or tacrolimus (n=1) was discontinued with sirolimus commenced immediately, initially aiming for a target trough level of 16 (12 to 20) ng/mL. If patients were not receiving mycophenolate (MMF) this was initiated at 1 g bid. The transfer period was covered with a tapering course of corticosteroids. In addition to monitoring clinical status, hematology, biochemistry, and sirolimus levels, graft function was assessed by echocardiography, ECG, and, where indicated, endomyocardial biopsy. Renal function improved in 12 patients (with 6 having a greater than 40% decrease in serum creatinine), remained unchanged in 1, and deteriorated in 1. Two patients who were converted at 15 and 139 months after transplantation experienced grade 3A rejection. One patient experienced a fall in ejection fraction without histologic evidence of rejection. Sirolimus was discontinued in three patients because of side effects: bone marrow suppression, presumed lymphocytic pneumonitis, and generalized acneform rash complicated by an axillary abcess; 50% of patients continue on sirolimus. In conclusion, withdrawal of CNIs after heart transplantation resulted in an improvement in renal function in most patients: 43% experienced a substantial improvement. CNI elimination protocols need to be refined to reduce the risk of breakthrough rejection and to minimize side effects while protecting renal function after heart transplantation.     

Sirolimus toxicity and vascular endothelial growth factor release from islet and renal cell lines

Presently, sirolimus (rapamycin) is used as both induction and maintenance immunosuppression in solid organ transplants, including whole pancreas and kidney, and islet transplantation. Sirolimus has been suggested to have deleterious effects on islet beta-cell and renal function. We investigated the effect of sirolimus on the viability of islets, podocytes, and renal tubular cells. Sirolimus reduced the viability of islets and HK-2 human proximal renal tubular cells in vitro. This toxic effect was associated with a reduction of vascular endothelial growth factor (VEGF) release by islets but not the proximal tubular cells. Sirolimus reduced both viability and VEGF production by murine beta-cells, and blockade of VEGF-164 was associated with a reduction in viability. Transfection of murine islets with adenoviral VEGF-165 improved islet viability. These data are consistent with the hypothesis that sirolimus is toxic to islets and beta-cells by blockade of VEGF-mediated survival pathways.