Risk factors for post-transplant lymphoproliferative disease in patients with cystic fibrosis.

The objective of this study was to retrospectively analyze risk factors associated with post-transplant lymphoproliferative disease (PTLD) in a cohort of 112 lung transplant recipients with cystic fibrosis (CF). Prior to transplantation, patients were tested for Epstein-Barr virus (EBV), human herpesvirus (HHV types 1, 2, 3, 6, and 8), herpes zoster virus, and cytomegalovirus (CMV) serologies. PTLD diagnosis was established based on increased EBV viral charge plus clinical/radiographic findings and confirmed by biopsy. Negative EBV and HHV serologies at the time of lung transplantation (LTx) were significant risk factors associated with development of PTLD in patients with CF in the univariate logistic regression analysis (p < 0.05) and also in the multivariate analysis (odds ratio of 77.5 and 12.5, respectively). CMV serology, CMV mismatch, acute rejection in the first three months following LTx, HLA-A3 antigen expression, and female gender did not affect PTLD. Our study confirmed the presence of a strong association between negative EBV serology at the time of LTx and PTLD and suggested an independent effect of negative HHV serology on PTLD.

Effect of cytochrome P450 2C19 genotype on voriconazole exposure in cystic fibrosis lung transplant patients.

PURPOSE: Voriconazole is widely used to treat invasive aspergillosis after lung transplantation. In cystic fibrosis patients, the interindividual variability in drug disposition complicates the optimal voriconazole dosing and increases the risk of toxicity. The objective of this retrospective study was to evaluate the influence of CYP2C19 genotype on voriconazole response in lung transplant patients with cystic fibrosis. METHODS: We retrospectively studied 24 Caucasian cystic fibrosis lung transplant recipients who received voriconazole. We analyzed the influence of CYP2C19 genotype (*2 and *17 alleles) on voriconazole exposure and maintenance dose and side effects. RESULTS: Heterozygous carriers of the CYP2C19*2-deficient allele required lower maintenance doses (440 ± 107 mg/day) compared with wild-type and CYP2C19*17-allele carriers (633 ± 197 mg/day and 600 ± 193 mg/day, respectively, P<0.05). The time to achieve the therapeutic range and the proportion of out-of-range concentrations were significantly higher in the CYP2C19*2 group (31.3% vs. 12.1% and 9.8% of above-range levels in the CYP2C19*1 and CYP2C19*17 groups, respectively) or CYP2C19*17 group (37.9% vs. 15.6% and 13% of below-range levels in the CYP2C19*1 and CYP2C19*2 groups, respectively) (P<0.01). No relationship was found between voriconazole toxicity and CYP2C19 status. CONCLUSIONS: In this frail population, voriconazole exposure is strongly influenced by CYP2C19 genotype, and determining the genotype before voriconazole initiation may help determine the initial dosing regimen that will promptly achieve therapeutic plasma levels without producing out-of-range levels.

Pharmacological considerations for azole antifungal drug management in cystic fibrosis lung transplant patients.

This paper aims to present our experience in the pharmacological approach of the management of azole antifungal drugs in cystic fibrosis lung transplant patients. Cystic fibrosis (CF) lung transplantation is associated with multi-factorial care management, because of immunosuppressive requirements, risk of infections, frequency of gastro-oesophageal reflux disease, hepatic alterations and CF pharmacokinetics (PK) specificities that result in important PK variability. CF is associated with frequent colonization of the airways by filamentous fungi, especially by Aspergillus species. Today the antifungal therapeutic arsenal offers several possibilities for long-term oral therapy including azole drugs (itraconazole, voriconazole and posaconazole). Therefore, nephrotoxic amphotericin B should be avoided. The liver is important in the pharmacological profile of azole drugs, due to metabolic elimination, hepatotoxicity and PK drug-drug interaction (DDI) involving CYP3A4 metabolic inhibition. Targets for such DDI are numerous, but immunosuppressive drugs are of major concern, justifying combined therapeutic drug monitoring (TDM) of both azoles (inhibitors) and immunosuppressants (targets) on an individualized patient basis to adjust the coprescription quantitatively. The risk of long under-dosed periods, frequently addressed in this population, could justify, on a PK basis, the need for combination with an exclusive parenteral antifungal while waiting for azole relevant drug level. High PK variability, the risk of low exposure, therapeutic issues and DDI management in this complex underlying disease justify close monitoring with systematic combined TDM of azole and immunosuppressants, in case of coprescription.

Safe management of tacrolimus together with posaconazole in lung transplant patients with cystic fibrosis.

Oral posaconazole (PSZ), an azole antifungal drug, was recently introduced for the treatment of invasive fungal infections. The prescription of PSZ together with the immunosuppressant tacrolimus (TRL) was evaluated in 14 lung transplant patients with cystic fibrosis. PSZ inhibited CYP3A4 TRL metabolism, resulting in a decrease of TRL dose by a factor of 3, with tapering to a mean of 2 mg/d. Previous studies with itraconazole and voriconazole showed that TRL dose could be decreased by factors of 5 and 4, respectively. Joint therapeutic drug monitoring of TRL and PSZ was carried out to investigate the high risk of interindividual variability associated with this coprescription in such patients.

Human leukocyte antigen-G expression after heart transplantation is associated with a reduced incidence of rejection.

BACKGROUND: Human leukocyte antigen (HLA)-G, a nonclassic major histocompatibility complex class I molecule expressed in the extravillous cytotrophoblast at the feto-maternal interface, is known to protect the fetus from maternal cellular immunity. In a preliminary study, we showed that HLA-G is expressed in the hearts of some patients after heart transplantation. METHODS AND RESULTS: In the present study, a larger number of patients was investigated to confirm this finding and to look for possible correlations between HLA-G expression and the number and types of rejection. Expression of HLA-G in endomyocardial biopsy specimens was investigated by immunohistochemical analysis, and detection of the soluble HLA-G in the serum was performed by immunoprecipitation followed by Western blot analysis. HLA-G was detected in the biopsy specimens and serum of 9 of 51 patients (18%). The number of episodes of acute rejection was significantly lower in HLA-G-positive patients (1.2+/-1.1) as compared with HLA-G-negative patients (4.5+/-2.8) (P<0.001). No chronic rejection was observed in HLA-G-positive patients, whereas 15 HLA-G-negative patients had chronic rejection (P<0.032). A longitudinal study of these patients reveals that the status of HLA-G expression was maintained after 6 months both in serum and in biopsy specimens. During this period, HLA-G-positive patients did not have chronic rejection. CONCLUSIONS: There is a significant correlation between rejection and HLA-G expression in the heart after transplantation. HLA-G expression and its effect in reducing the incidence and severity of rejection seem to be stable throughout the evolution.

Acute vascular humoral rejection in a sensitized cardiac graft recipient: diagnostic value of C4d immunofluorescence.

A 37-year-old female patient had a cardiac transplantation for dilated cardiomyopathy. She was sensitized by two pregnancies showing anti-human leukocyte antigen I and II antibodies. The pretransplantation crossmatch was negative, but she developed acute humoral rejection characterized by vascular C4d deposits, arteriolitis, and intravascular leukocyte accumulation and adhesion in venules. Although C4d deposits disappeared in 4 weeks, she had persistent endothelial cell activation (endothelial expression of ELAM-1, VCAM-1, or human leukocyte antigen class II) throughout the 6 months of follow-up. Although she received intensive immunosuppression, she presented three episodes of acute cellular rejection during that period of time. This case shows that C4d deposits represent a sensitive marker of acute humoral rejection in cardiac transplantation. Therefore, C4d immunofluorescence should be more frequently assessed in endomyocardial biopsies.

Ciclosporin population pharmacokinetics and Bayesian estimation in thoracic transplant recipients.

BACKGROUND AND OBJECTIVES: Therapeutic drug monitoring of ciclosporin has been recognized as an essential tool in the management of allograft transplant recipients, as it could help improve their outcome. However, there is still no consensus about the optimal method for monitoring ciclosporin after thoracic transplantation. Better knowledge of the pharmacokinetics of ciclosporin in thoracic transplant patients and design of tools dedicated to ciclosporin monitoring could help its practice and its outcome in this population of patients. The aims of this study were to (i) investigate the population pharmacokinetics of ciclosporin in thoracic (heart or lung) transplant patients and study the influence of a range of potential covariates, including demographic, clinical and genetic factors, on pharmacokinetic parameters; and (ii) develop a Bayesian estimator able to predict the individual pharmacokinetic parameters and exposures indices in this population of patients. METHODS: The analysis was performed with 187 full pharmacokinetic profiles obtained in 57 lung and 19 heart transplant patients within the first year post-transplantation. A population pharmacokinetic model was developed by non-linear mixed-effects modelling using NONMEM(®) (version 7.1) from an index dataset (118 profiles). On the basis of this population model and a limited number of blood samples, a Bayesian estimator able to determine ciclosporin area under the blood concentration-time curve (AUC) during a dosage interval was built and evaluated in the validation dataset (69 profiles). RESULTS: Ciclosporin pharmacokinetics were described using a two-compartment model with time-lagged first order absorption and first-order elimination. The final population model included sex as a covariate: ciclosporin apparent oral clearance was on average 37 % faster in male than in female patients (34.8 vs. 25.4 L/h, p < 0.001). Good predictive performance of the Bayesian estimator was obtained using three blood concentrations measured at 40 min, 2 h and 4 h post-dose, with a non-significant bias of -5 % between the estimated and the reference trapezoidal AUC and a good precision (relative mean square error = 13 %). CONCLUSION: Ciclosporin population pharmacokinetic analysis in thoracic transplant patients (including patients with cystic fibrosis) showed a significant influence of sex on apparent clearance. The Bayesian estimator developed in this study yielded accurate prediction of ciclosporin exposure in this population throughout the first year post-transplantation. This tool may allow routine ciclosporin dose individualization.

Expression of calcineurin activity after lung transplantation: a 2-year follow-up.

The objective of this pharmacodynamic study was to longitudinally assess the activity of calcineurin during the first 2 years after lung transplantation. From March 2004 to October 2008, 107 patients were prospectively enrolled and their follow-up was performed until 2009. Calcineurin activity was measured in peripheral blood mononuclear cells. We report that calcineurin activity was linked to both acute and chronic rejection. An optimal activity for calcineurin with two thresholds was defined, and we found that the risk of rejection was higher when the enzyme activity was above the upper threshold of 102 pmol/mg/min or below the lower threshold of 12 pmol/mg/min. In addition, we report that the occurrence of malignancies and viral infections was significantly higher in patients displaying very low levels of calcineurin activity. Taken together, these findings suggest that the measurement of calcineurin activity may provide useful information for the management of the prevention therapy of patients receiving lung transplantation.

Pathologic classification of antibody-mediated rejection correlates with donor-specific antibodies and endothelial cell activation.

BACKGROUND: Humoral immune responses during heart transplantation may result in antibody-mediated rejection (AMR), which is now taken into account on endomyocardial biopsy (EMB) specimens and ranked according to the pathologic AMR (pAMR) grades of the International Society for Heart and Lung Transplantation classification. This classification might benefit from new immunohistological markers and validation by others biomarkers, namely donor-specific antibodies (DSA). METHODS: From the 293 protocol EMBs performed in 113 patients in our institution during a 1-year period for this prospective study, 280 EMB specimens were available with both histology and immunohistochemistry. C4d and labeling of intravascular cells by cluster of differentiation (CD) 68 were performed on paraffin sections. Available sera (n = 150) concomitant of EMB specimens were tested for the presence of DSA. All of the pAMR+ EMB specimens, along with a set of randomized pAMR0 EMB specimens, were immunolabeled for mammalian target of rapamycin (mTOR) effectors, phosphorylated 70 S6-kinase (p70S6K) and phosphorylated S6 ribosomal protein (pS6RP). RESULTS: AMR was diagnosed in 37 EMB specimens (13.2%): 1 pAMR1(I+), 27 pAMR1(H+), and 9 pAMR2. The proportion of DSA-positive EMB varied according to the pAMR grade, with pAMR0, pAMR1(H+), and pAMR2 EMB presenting 17.6%, 77.3%, and 100% of DSA-positivity, respectively. Among the 30 pAMR+ specimens with available DSA testing and the 30 pAMR0 randomized specimens, mTOR pathway immunohistochemistry showed endothelial cell positivity for p70S6K in 17 pAMR+ EMB specimens (56.7%) and in 1 pAMR0 EMB specimen (3.3%). pS6RP was detected in 8 pAMR+ EMB specimens (26.7%) and in 1 pAMR0 EMB specimen (3.3%). CONCLUSIONS: p70S6K and pS6RP immunohistochemistry afford new markers of AMR on EMB specimens because their expression is correlated with microcirculation inflammation and DSA. The correlation of DSA with pAMR grade suggests that this grading system is valid.

Pulmonary resection after lung transplantation in cystic fibrosis patients.

Pulmonary resection after lung transplantation in end-stage cystic fibrosis presents unique challenges, and scant literature exists to guide physicians. We retrospectively reviewed 78 transplants for cystic fibrosis performed between 2003 and 2008. Fourteen patients underwent posttransplantation pulmonary resection. We analyzed the indications, surgical procedures, outcomes, and survival. Three pneumonectomies, 4 lobectomies, and 11 wedge resections were carried out. We identified 2 groups based on indication: a diagnostic group, and a therapeutic group of patients in whom the indications were septic native lung in 2, allograft infection in 2, lobar torsion in 2, pulmonary infarction in 2, and size mismatch in 4. The mean intensive care unit and hospital stays were 29 and 50 days, respectively. Four (28.57%) patients died during follow-up, including 2 who underwent pneumonectomy; 10 (71.43%) are still alive. Survival was 43.43 ± 8.06 months, and it was not significantly different from that in cystic fibrosis patients who had lung transplantation without pulmonary resection. Pulmonary resection following lung transplantation in cystic fibrosis patients showed acceptable survival and surgical risk, but metachronous pneumonectomy was associated with higher mortality.

Mechanical ventricular assistance in heart failure: pathology of the cardiac apex removed during device implantation.

BACKGROUND: Ventricular assistance device (VAD) implantation provides large ventricular core biopsies available for pathological assessment. We present here the pathological data from 60 apex removed during a 7-year-period in a single institution. RESULTS: The most frequent specific lesions were ischemic myocardial damage. Nonspecific pathological features were quite as frequently observed and correspond either to dilated cardiomyopathies, chronic ischemic cardiopathies, or miscellaneous conditions. Myocarditis represented 10 out of the 60 cases. The pathological data changed the clinical diagnosis in four cases: 1 case of juvenile hemochromatosis featuring as myocarditis and three cases of myocarditis featuring as dilated cardiomyopathies. CONCLUSION: Apex pathological analysis provides definite diagnosis and contributes to determine the cases which the cardiac disease have a possibility to recover under VAD.

Cardiac stem cells in the real world.

OBJECTIVE: Cardiac stem cell transplantation as a potential means of regenerating infarcted myocardium is currently receiving a great deal of interest. However, data on these endogenous cardiac precursors are primarily derived from animal studies, and their clinical relevance still remains elusive. METHODS: We prospectively screened 32 endomyocardial biopsies harvested from heart transplant recipients (off rejection episodes) and 18 right appendage biopsies collected during coronary artery bypass surgery, and processed the tissue specimens for the immunohistochemical detection of markers of stemness (c-kit, MDR-1, Isl-1), hematopoietic origin (CD45), mast cells (tryptase), endothelial cells (CD105), and cardiac lineage (Nkx2.5). Confocal microscopy was used for colocalization experiments. Three right appendage biopsies were also cultured for 2 to 3 weeks, at the completion of which c-kit-positive cells were sorted by flow cytometry. RESULTS: In endomyocardial biopsies, a median number of 2.7 (1.8-4) c-kit-positive cells/mm(2) were found, and this number was even significantly smaller in right appendage biopsies (1 [0.5-1.8] c-kit-positive cell/mm(2), P = .01). All of these c-kit-positive cells co-stained for CD45 and were more specifically identified as mast cells by their positive staining for the specific tryptase marker. However, none of the c-kit-positive cells expressed the markers of stemness MDR-1 and Isl-1 or colocalized with CD105. Flow cytometry confirmed the small number of c-kit-positive cells in cultured right atrial appendages. CONCLUSION: These data raise a cautionary note on the therapeutic exploitation of cardiac stem cells in patients with ischemic cardiomyopathy, who may be the elective candidates for regenerative therapy.

Unilateral pulmonary edema after pulmonary embolism in a bilateral lung transplant patient.

We report a case of unilateral pulmonary edema due to the decompensation of an asymptomatic ipsilateral pulmonary venous stenosis by a contralateral pulmonary embolism. Emergency surgery included pulmonary embolectomy and refashioning of the stenotic pulmonary venous anastomosis.

Human leukocyte antigen sensitization in ventricular assist device recipients: a lesser risk with the DeBakey axial pump.

BACKGROUND: Previous reports, all concerning pulsatile devices, have indicated an increased risk of development of circulating antileukocyte antigen (HLA; human leukocyte antigen) antibodies during ventricular assist device (VAD) support. We investigated sensitization in patients implanted with the DeBakey VAD (MicroMed Technology, Inc, Houston, TX) axial flow pump as a bridge to heart transplantation. METHODS: Inclusion criteria for this prospective study were the following. Patients implanted with the DeBakey VAD axial flow pump, without HLA antibodies prior to implantation, with a duration of support of at least one month. The HLA antibody testing for IgG and IgM class I and II antibodies was performed weekly during support, using both a complement dependant cytotoxicity assay and an enzyme-linked immunosorbent assay (ELISA). Retrospective cross match was performed for all patients transplanted. The occurrence of graft rejection was determined by regular endomyocardial biopsies after heart transplantation, graded according to the International Society for Heart and Lung Transplantation (ISHLT) guidelines. Additionally, the transfusion history was reviewed for all patients. RESULTS: Fourteen patients were included representing 1,220 cumulative patient-days of support (mean duration time on support, 87 days). No patient developed detectable IgG antibodies to class I or II. One patient had a positive ELISA, corresponding to nonsignificant (6/30) class I IgM antibodies at 3 weeks postimplantation. Ten patients underwent successful heart transplantation, representing 156 cumulative months. No retrospective cross match was positive. The percentage of significant acute rejection episodes (ISHLT grade 3A or more) was 6% and 4.3% in the first 6 months and from 6 to 12 months, respectively. No vascular rejection was noted. The posttransplantation survival rate was 87% at 6 months and 75% at 1 year, respectively. CONCLUSIONS: Patients implanted with the DeBakey VAD axial flow pump as a bridge to heart transplantation do not appear to be exposed to an increased risk of sensitization.