Efficacy of tacrolimus rescue therapy in refractory acute rejection after lung transplantation.

BACKGROUND: Encouraging results in transplantation of other solid organs led to investigation of the use of tacrolimus in lung transplantation as a salvage immunosuppressant in persistent acute rejection. METHODS: The incidence and severity of acute rejection and the number of steroid pulses were analyzed in 20 lung recipients who were converted from a cyclosporine- to a tacrolimus-based immunosuppressive regimen because of refractory biopsy-proven acute rejection. RESULTS: Tacrolimus was started 12.0 +/- 13.0 months after transplantation, and the mean follow-up was 25.0 +/- 13.7 months. After shifting to tacrolimus, a significant decline was observed in both the number of acute rejections per patient (3.0 +/- 1.56 to 0.85 +/- 1.14, p < 0.0001), and the incidence of acute rejection per 100 patient-days (1.52 +/- 0.99 to 0.14 +/- 0.21, p < 0.0001). Furthermore, the average histologic grade of rejection decreased from 1.9 +/- 0.8 to 0.4 +/- 0.5 (p < 0.0001). Methylprednisolone pulses similarly decreased from 1.9 +/- 1.3/patient to 0.3 +/- 0.7/patient (p < 0.0001). During cyclosporine immunosuppression, the mean forced expiratory volume in 1 second decreased to 84.4% +/- 13.3% of individual best value. The average lung function parameters were stable 3 months after the change of medication, and then began to improve. After an average follow-up of 36.5 +/- 19.2 months, 2 patients have developed bronchiolitis obliterans syndrome (one has Stage 1 and one has Stage 3). CONCLUSION: Conversion to a tacrolimus-based immunosuppressive regimen for refractory acute lung rejection is associated with reduced incidence and severity of acute rejection episodes, steroid sparing, and stabilization or improvement of pulmonary function.     

Sirolimus-based rescue therapy after rejection in liver transplantation

Abstract:  Steroid-resistant acute rejection (SR-AR) and ductopenic rejection (DR) after liver transplantation are infrequent, but difficult to manage. We performed a retrospective review of patients with SR-AR or DR treated with sirolimus-based therapy. Since 2002, we have treated five patients with SR-AR and eight patients with DR. All patients had associated renal insufficiency. Six patients showed no response, of whom five died and one was retransplanted. In six cases, rejection was resolved after changing, while one improved. Therefore, the total response rate was 54%. Ten of 13 patients (77%) suffered some type of adverse event. Ten of these (77%) suffered a hematologic event. Four patients (31%) had infection. Only two patients had to discontinue treatment. Univariate analysis showed that pre-conversion bilirubin was lower in responders (Bilirubin: R: 210 ± 205 vs. NoR: 554 ± 159 μmol/L; p = 0.07 and Creatinine clearance higher: R: 37 ± 11 vs. NoR: 25   ±   11 mL/min; p = 0.09). Sirolimus trough levels one month after switching were higher in responders (R: 11 ± 1.8 vs. NoR: 7.5 ± 3.3 ng/mL; p = 0.03). We conclude that a dual therapy regimen of tacrolimus and sirolimus can achieve a high response rate as a rescue therapy for SR-AR and DR, provided it is begun as soon as possible.     

Sirolimus rescue therapy for refractory rejection in renal transplantation.

BACKGROUND: Acute renal allograft rejection episodes refractory to antilymphocyte preparations almost inevitably progress to transplantation loss. To reverse ongoing rejection processes, we administered sirolimus (RAPA) after failure of conventional immunosuppressive regimens including full courses of antilymphocyte sera. METHODS: All 36 renal transplantation recipients reported herein displayed either Grade IIB or Grade III biopsy-proven (Banff 1993 criteria) ongoing rejection episodes despite prior treatment with pulse and/or oral recycling of steroids and at least one 14- to 21-day course of murine (OKT3) or equine (ATGAM) antilymphocyte treatment. We compared the actual 12-month outcomes of two demographically similar cohorts of patients treated for refractory rejection with RAPA (Group I; n=24) or mycophenolate mofetil (MMF; Group II; n=12) added to a baseline regimen of cyclosporine (CsA)/prednisone (Pred). RESULTS: Rescue therapy reversed the renal dysfunction in 96% of patients in the RAPA group versus 67% in the MMF group (P=0.03) despite the fact that a greater fraction of patients in the RAPA (17 of 24) than the MMF group (6 of 12) had experienced two or more episodes of acute rejection before study entry and the fact that the recurrent bouts of acute rejection occurred within the first 6 months posttransplant in 94% of patients in the RAPA group compared with 50% (P=0.005) in the MMF group. Among the patients who were reversed successfully, the rates of rebound acute rejection were similar (4% vs. 8%). The mean serum creatinine values were slightly, although not significantly, lower among RAPA than MMF patients at 1, 3, 6, and 12 months: namely, 2.6 vs. 2.8, 2.8 vs. 3.2, 3.0 vs. 3.3, and 2.8 vs. 3.2 mg/dL, respectively. The 1-year patient and graft survival rates were similar: namely, 88% vs. 92% and 83% vs. 67% for the RAPA versus MMF groups. CONCLUSION: RAPA is a potent immunosuppressive agent for the treatment of refractory renal allograft rejection.     

Current views on chronic rejection after lung transplantation

Chronic lung allograft dysfunction (CLAD) was recently introduced as an overarching term mainly to classify patients with chronic rejection after lung transplantation, although other conditions may also qualify for CLAD. Initially, only the development of a persistent and obstructive pulmonary function defect, clinically identified as bronchiolitis obliterans syndrome (BOS), was considered as chronic rejection, if no other cause could be identified. It became clear in recent years that some patients do not qualify for this definition, although they developed a chronic and persistent decrease in FEV₁, without another identifiable cause. As the pulmonary function decline in these patients was rather restrictive, this was called restrictive allograft syndrome (RAS). In the present review, we will further elaborate on these two CLAD phenotypes, with specific attention to the diagnostic criteria, the role of pathology and imaging, the risk factors, outcome, and the possible treatment options.     

Acute allograft rejection after lung transplantation: diagnosis and therapy

Acute rejection remains a significant problem after lung transplantation. While it generally is a treatable condition, significant resources and therapies are directed toward its prevention and resolution. Its larger significance undoubtedly rests in its contribution to the pathogenesis of BOS. Significant questions regarding the origins of AR, the role of LBB, alternative histologic appearances of acute allograft injury, and optimal therapy remain. Controversy regarding the utility of surveillance bronchoscopy and preemptive treatment of occult AR persists because of lack of conclusive evidence. Future investigations might resolve these matters and provide more efficacious and less toxic therapies that will hopefully reduce the impact of chronic rejection and improve long-term outcomes.     

The need for a new animal model for chronic rejection after lung transplantation

The single most important cause of late mortality after lung transplantation is obliterative bronchiolitis (OB), clinically characterized by a decrease in lung function and morphologically by characteristic changes. Recently, new insights into its pathogenesis have been acquired: risk factors have been identified and the use of azithromycin showed a dichotomy with at least 2 different phenotypes of bronchiolitis obliterans syndrome (BOS). It is clear that a good animal model is indispensable to further dissect and unravel the pathogenesis of BOS. Many animal models have been developed to study BOS but, so far, none of these models truly mimics the human situation. Looking at the definition of BOS, a good animal model implies histological OB lesions, possibility to measure lung function, and airway inflammation. This review sought to discuss, including pros and cons, all potential animal models that have been developed to study OB/BOS. It has become clear that a new animal model is needed; recent developments using an orthotopic mouse lung transplantation model may offer the answer because it mimics the human situation. The genetic variants among this species may open new perspectives for research into the pathogenesis of OB/BOS.     

Donor brain death aggravates chronic rejection after lung transplantation in rats

BACKGROUND: Many recipients of lung transplants from brain-dead donors develop bronchiolitis obliterans, a manifestation of chronic rejection. It has been shown that brain death increases inflammatory mediators and accelerates acute rejection in kidney, liver, and heart transplants. In this study, the authors investigated the hypothesis that brain death increases inflammatory mediators in the donor lung and subsequently aggravates chronic rejection of the lungs after transplantation in rats. METHODS: Brain death was induced in F344 rats by inflation of a subdurally placed balloon catheter. After 6 hr, donor lungs were assessed for influx of leukocytes, expression of cell adhesion molecules, and cytokine mRNA expression. For assessment of the lung after transplantation, lungs from brain-dead F344 rats were transplanted into WKY rats. Lung function after transplantation was monitored by chest radiographs during an observation period of 100 days. At the end of this period, the lungs were histologically examined; also, cytokine mRNA expression was measured. Lungs from ventilated living donors and living donors served as controls. RESULTS: After 6 hr of brain death, influx of polymorphonuclear cells and macrophages and expression of vascular cell adhesion molecule-1 in the donor lungs was increased. After transplantation at postoperative day 100, the lung function was significantly decreased compared with allografts from living donors. In the lung allografts from brain-dead donors, histologic symptoms of chronic rejection were obvious, including severe intimal hyperplasia but without bronchiolitis obliterans. Interleukin-2 mRNA was significantly increased in allografts from brain-dead donors compared with living donors. CONCLUSIONS: This study shows that brain death induces an inflammatory response in the donor lung and subsequently aggravates chronic rejection after transplantation. This may explain the clinical difference in long-term function between lungs from cadaveric donors and living donors.     

Fulminant hyperacute rejection after unilateral lung transplantation

Hyperacute rejection (HAR) is a well-known complication in renal and cardiac transplantation, but rare in lung recipients. We present a case of HAR of the lung graft with a fatal outcome of a male patient with preformed class II anti-HLA antibodies.     

Reliability for grading acute rejection and airway inflammation after lung transplantation.

BACKGROUND: The Lung Rejection Study Group (LRSG) created a scheme for grading acute allograft rejection in 1990 and then revised it in 1996, but virtually no studies have evaluated the reliability of this formulation. This investigation assessed the reliability of the current LRSG system by determining inter- and intrareader agreement for grading transbronchial biopsy samples from lung transplant recipients. METHODS: Biopsy samples from a cohort of 204 recipients were reviewed and classified by a single pathologist who was blinded to original interpretations. The "A" and "B" rejection grades from this contemporary review were compared with original grades by the kappa statistic. RESULTS: For "A" grading, weighted kappa was 0.65 (95% confidence interval [CI] 0.60-0.70) for interreader agreement (n = 529 specimens) and 0.65 (95% CI 0.53-0.76) for intrareader agreement (n = 97 specimens). For "B" grading, weighted kappa was 0.26 (95% CI 0.14-0.39) for interreader agreement (n = 164 specimens) and 0.33 (95% CI 0.15-0.51) for intrareader agreement (n = 58 specimens). CONCLUSIONS: On the basis of the analysis of the LRSG scheme, "A" grades exhibit very good reliability, but "B" grades have only fair reliability, and steps to improve this shortcoming should be taken.     

Risk factors for chronic rejection after pediatric liver transplantation

BACKGROUND: Chronic rejection is a major cause of graft failure and a frequent reason for retransplantation after pediatric liver transplantation. Identification of risk factors for chronic rejection in pediatric transplant recipients is vital to understanding the pathogenesis of chronic rejection and may help prevent further graft loss. METHODS: The study population consisted of 285 children with 385 liver transplants performed at University of Chicago between 1991 and 1999. Logistic regression analysis was used to evaluate risk factors for chronic rejection, including age, sex, race, type of graft (living related vs. cadaveric), native liver disease, acute rejection episodes, cytomegalovirus (CMV) infection, and posttransplant lymphoproliferative disease (PTLD). RESULTS: The chronic rejection rate was significantly lower in recipients of living-related grafts than in recipients of cadaveric grafts (4% vs. 16%, P=0.001). African-American recipients had a significantly higher rate of chronic rejection than did Caucasian recipients (26% vs. 8%, P<0.001). Numbers of acute rejection episodes, transplantation for autoimmune disease, occurrence of PTLD, and CMV infection were also significant risk factors for chronic rejection. However, recipient age, gender, donor-recipient gender mismatch, and donor-recipient ethnicity mismatch were not associated with higher incidence of chronic rejection CONCLUSION: We have identified a number of risk factors for chronic rejection in a large group of pediatric liver allograft recipients. We believe that donor-recipient matching for gender or race is not likely to reduce the incidence of chronic rejection. The elucidation of the mechanisms by which living-related liver transplantation affords protection against chronic rejection may provide insight into the immunogenetics of chronic rejection and help prevent further graft loss.     

Rituximab therapy for acute humoral rejection after kidney transplantation

A pilot study was performed on eight consecutive renal-transplant (RT) patients presenting with acute humoral rejection (AHR) to assess the efficacy of monoclonal anti-B cell antibodies, such as rituximab (375 mg/m weekly) for 3 to 5 consecutive weeks, in addition to plasma exchange (PE), steroids, mycophenolate mofetil, and tacrolimus. AHR was associated with increased serum creatinine, the appearance of donor-specific alloantibodies (DSA), and the presence of C4d in a transplant biopsy. After a follow-up of 10 months (range 7-23), patient and graft survivals were 100% and 75%, respectively. Renal function improved in six cases in which serum creatinine decreased from 297+/-140 to 156+/-53 micromol/L (P=0.015); graft loss occurred in two cases; and four patients had infectious complications. At last follow-up, DSA had disappeared or decreased in four cases. Rituximab therapy, in addition to PE, might be of benefit for RT patients presenting with AHR.