Cardiac toxicity of combined vemurafenib and cobimetinib administration
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Vemurafenib and cobimetinib are extremely effective in treating V600E-mutated metastatic melanoma, but their use is associated with toxic cardiac effects. Vemurafenib-induced prolonged QTc interval may be associated with ventricular fibrillation and sudden cardiac death. Cobimetinib-induced myocardial damage may lead to severely reduced heart function and lethal heart failure. Few data are available about the time course of recovery after these side effects. We provide the first description of cardiac recovery after potentially fatal cardiac side effects due to vemurafenib and cobimetinib administration. A 51-year-old woman was admitted to our hospital with diarrhea, vomiting, and asthenia. At admission, her left ventricular ejection fraction (LVEF) was severely reduced and QTc interval was extremely elongated (normal range QTc ≤ 440 ms). Blood levels of troponin I (normal values below 0.07 ng/mL) and brain natriuretic peptide (brain natriuretic peptide (BNP), normal range < 100 pg/mL) were elevated. During hospitalization, she developed recurrent runs of torsades de pointes degenerating into ventricular fibrillation, requiring direct current electric shock (DC shocks). Vemurafenib and cobimetinib were discontinued. Three weeks later, QTc was still higher than 500 ms and LVEF lower than 30%: an implantable cardioverter-defibrillator (ICD) was implanted. Myocardial function improved within 1 month, and QTc intervals became 500 ms 1 week later. After 6 months, a normal ejection fraction (> 55%) was observed, and the QTc interval was 455 ms. The patient died rather from metastatic melanoma recurrence 8 months later. This case report highlights the time-course of recovery after combined vemurafenib-cobimetinib-induced severe myocardial damage. Further research is warranted to assess whether and how antineoplastic therapy may be resumed after QT normalization and heart function recovery.
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Clinical usefulness of gene-expression profile to rule out acute rejection after heart transplantation: CARGO II.

AIMS: A non-invasive gene-expression profiling (GEP) test for rejection surveillance of heart transplant recipients originated in the USA. A European-based study, Cardiac Allograft Rejection Gene Expression Observational II Study (CARGO II), was conducted to further clinically validate the GEP test performance. METHODS AND RESULTS: Blood samples for GEP testing (AlloMap(®), CareDx, Brisbane, CA, USA) were collected during post-transplant surveillance. The reference standard for rejection status was based on histopathology grading of tissue from endomyocardial biopsy. The area under the receiver operating characteristic curve (AUC-ROC), negative (NPVs), and positive predictive values (PPVs) for the GEP scores (range 0-39) were computed. Considering the GEP score of 34 as a cut-off (>6 months post-transplantation), 95.5% (381/399) of GEP tests were true negatives, 4.5% (18/399) were false negatives, 10.2% (6/59) were true positives, and 89.8% (53/59) were false positives. Based on 938 paired biopsies, the GEP test score AUC-ROC for distinguishing ≥3A rejection was 0.70 and 0.69 for ≥2-6 and >6 months post-transplantation, respectively. Depending on the chosen threshold score, the NPV and PPV range from 98.1 to 100% and 2.0 to 4.7%, respectively. CONCLUSION: For ≥2-6 and >6 months post-transplantation, CARGO II GEP score performance (AUC-ROC = 0.70 and 0.69) is similar to the CARGO study results (AUC-ROC = 0.71 and 0.67). The low prevalence of ACR contributes to the high NPV and limited PPV of GEP testing. The choice of threshold score for practical use of GEP testing should consider overall clinical assessment of the patient's baseline risk for rejection.

Performance of gene-expression profiling test score variability to predict future clinical events in heart transplant recipients.

BACKGROUND: A single non-invasive gene expression profiling (GEP) test (AlloMap®) is often used to discriminate if a heart transplant recipient is at a low risk of acute cellular rejection at time of testing. In a randomized trial, use of the test (a GEP score from 0-40) has been shown to be non-inferior to a routine endomyocardial biopsy for surveillance after heart transplantation in selected low-risk patients with respect to clinical outcomes. Recently, it was suggested that the within-patient variability of consecutive GEP scores may be used to independently predict future clinical events; however, future studies were recommended. Here we performed an analysis of an independent patient population to determine the prognostic utility of within-patient variability of GEP scores in predicting future clinical events. METHODS: We defined the GEP score variability as the standard deviation of four GEP scores collected ≥315 days post-transplantation. Of the 737 patients from the Cardiac Allograft Rejection Gene Expression Observational (CARGO) II trial, 36 were assigned to the composite event group (death, re-transplantation or graft failure ≥315 days post-transplantation and within 3 years of the final GEP test) and 55 were assigned to the control group (non-event patients). In this case-controlled study, the performance of GEP score variability to predict future events was evaluated by the area under the receiver operator characteristics curve (AUC ROC). The negative predictive values (NPV) and positive predictive values (PPV) including 95 % confidence intervals (CI) of GEP score variability were calculated. RESULTS: The estimated prevalence of events was 17 %. Events occurred at a median of 391 (inter-quartile range 376) days after the final GEP test. The GEP variability AUC ROC for the prediction of a composite event was 0.72 (95 % CI 0.6-0.8). The NPV for GEP score variability of 0.6 was 97 % (95 % CI 91.4-100.0); the PPV for GEP score variability of 1.5 was 35.4 % (95 % CI 13.5-75.8). CONCLUSION: In heart transplant recipients, a GEP score variability may be used to predict the probability that a composite event will occur within 3 years after the last GEP score. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT00761787.

Successful treatment of a classic Hodgkin lymphoma-type post-transplant lymphoproliferative disorder with tailored chemotherapy and Epstein-Barr virus-specific cytotoxic T lymphocytes in a pediatric heart transplant recipient.

CHL type is the least common major form of EBV-related PTLD but rarely occurs in pediatric recipients; development of CHL subsequent to other PTLD subtypes in the same transplant recipient is even more unusual. Because of its rarity, indications on the best treatment strategy are limited. Patients have been mostly treated with standard HL chemotherapy/radiotherapy, and prognosis seems more favorable than other monomorphic PTLDs. Herein, we describe a pediatric case of EBV-associated, stage IV-B, CHL arising in a heart allograft recipient eight yr after diagnosis of B-cell polymorphic PTLD. The patient was successfully treated with adjusted-dose HL chemotherapy and autologous EBV-specific CTL, without discontinuation of maintenance immunosuppression. At two yr from therapy completion, the patient is in CR with stable organ function. With this strategy, it may be possible to reproduce the good prognostic data reported for CHL-type PTLD, with decreased risk of organ toxicity or rejection.

Fludarabine, cyclophosphamide, doxorubicin (FCD), and rituximab: a remission induction therapy for aggressive pediatric post-transplant lymphoproliferative disease (PTLD).

Management of aggressive, usually late-occurring, post-transplant lymphoproliferative disorders (PTLDs), a life-threatening complication after solid organ transplants, remains controversial. Four children affected by aggressive CD20+ PTLDs received a chemo-immunotherapy regimen for remission induction based on fludarabine, cyclophosphamide, doxorubicin, and rituximab, associated with a rapid discontinuation of immunosuppression (IS). Subsequent consolidation chemotherapy consisted of Berlin-Frankfurt-Münster-modified blocks. All patients achieved a complete remission, which persisted for 25, 68+, 80+, and 103+ months after diagnosis. Therapy was well tolerated. No patients developed allograft rejection during PTLD treatment. Our experience suggests that this chemo-immunotherapeutic approach may be an effective treatment strategy while allowing for a concomitant discontinuation of IS.

Incidence and clinical predictors of primary opportunistic deep cutaneous mycoses in solid organ transplant recipients: a multicenter cohort study.

BACKGROUND: Primary opportunistic deep cutaneous fungal infections may cause significant morbidity and mortality in solid organ transplant recipients (OTR), but no data exist about their incidence, timing, and clinical predictors in a long-term follow-up. PATIENTS AND METHODS: A series of 3293 consecutive OTR including 1991 kidney, 929 heart, and 373 liver transplant recipients were enrolled. Patients were regularly followed up since time at transplantation (mean 5.5 yr +/-5.9 SD) and primary opportunistic fungal infections registered. Persons-year at risk (PYs), incidence rates (IR), incidence rate ratios (IRR), and 95% confidence intervals were computed. RESULTS: Twenty-two cases of deep cutaneous mycoses were detected, (IR 1.2 cases per 1000 PYs) after a mean follow-up time since transplantation of 2.5 yr +/- 2.0 SD (median 1.8 yr). Six patients had subsequent systemic involvement and three patients died of systemic dissemination. A higher risk for mycoses was observed in the first two yr after transplantation, (IRR 35.9, p < 0.0001), in renal transplant recipients (IRR 5.1 p = 0.030), and in patients transplanted after the age of 50 (IRR 11.5 p = 0.020). CONCLUSIONS: Primary deep cutaneous opportunistic mycoses in OTR occur mainly in the first two yr after transplantation, in renal transplant recipients, and in older patients.

Comparison of the Innofluor certican assay with HPLC-UV for the determination of everolimus concentrations in heart transplantation.

OBJECTIVES: Therapeutic monitoring of everolimus with chromatographic methods (HPLC) enabled effective immunosuppression while limiting the incidence of drug-related adverse events. A fluorescence polarization immunoassay (FPIA) has been recently developed for the assessment of everolimus levels. The present study was designed to evaluate FPIA performance and to compare it to HPLC. DESIGN AND METHODS: The performance of HPLC and FPIA was initially tested using drug-free whole blood spiked with different amount of everolimus concentrations and, subsequently, by analyzing 113 trough blood samples from heart transplant recipients chronically given everolimus as part of their immunosuppressive regimen. RESULTS: Inaccuracy and imprecision of both methods were below 15%. The correlation between everolimus concentrations and measured FPIA and HPLC was good, with a Pearson coefficient of 0.9118. The FPIA gave a mean overestimation of 24.3% as compared with HPLC. As additional analysis, cross-reactivity ranging from 85.4% to 138.0% was found with sirolimus, an immunosuppressant with a chemical structure close to everolimus. CONCLUSION: The FPIA demonstrated acceptable performance for therapeutic drug monitoring of everolimus, and is a viable alternative to HPLC-based methods.

Risk-adapted Treatment for Severe B-Lineage Posttransplant Lymphoproliferative Disease After Solid Organ Transplantation in Children.

BACKGROUND: Optimal management of posttransplant lymphoproliferative disease (PTLD) remains to be defined due to heterogeneity of this condition and lack of predictors of the outcome. Here we report our experience with pediatric PTLD nonresponsive to immunosuppression (IS) withdrawal, managed after stratification into high and low risk according to the presenting features. METHODS: This is a single-center retrospective review of prospectively enrolled patients. From 2001 to 2011, 17 children were diagnosed with severe B-lineage, CD20+, PTLD after a median of 37 months (range, 5-93) from liver (12), heart (4), or multiorgan (1) transplantation. Treatment was tailored on 2 risk groups: (1) standard-risk (SR) patients received IS reduction and rituximab; (2) high-risk (HR) patients received IS discontinuation, rituximab and polychemotherapy. RESULTS: The cumulative incidence of rejection at 1 and 5 years after the diagnosis of PTLD was 35% (95% confidence interval [95% CI], 18-69%) and 53% (33-85%), respectively, whereas the disease-free survival at 1 and 5 years was 94% (95% CI, 65-99%) and 75% (45-90%), respectively. Three children died, PTLD-free, from different transplant-related complications: primary nonfunction after retransplantation (liver), cytomegalovirus disease 21 months after PTLD treatment (liver), graft dysfunction 25 months after PTLD (heart). CONCLUSIONS: Severe B-lineage PTLD after solid organ transplantation may be classified as SR or HR and treated accordingly with a tailored protocol obtaining a satisfactory long-term outcome. This approach accomplishes the control of lymphoproliferation in severe forms as well as the minimization of toxicity in milder PTLDs.

Energy metabolism in diabetic and nondiabetic heart transplant recipients.

OBJECTIVE: This study examined the metabolic effects of heart transplantation in patients in end-stage cardiac failure. RESEARCH DESIGN AND METHODS: A total of 18 patients after heart transplantation for end-stage heart disease (age 47 +/- 3 years; transplant age 5.5 +/- 1.5 years; BMI 25.8 +/- 0.8 kg/m(2); cyclosporin A 4.2 +/- 0.6 mg/[kg.day]; azathioprine 0.87 +/- 0.31 mg/[kg.day]), 12 patients with type 2 diabetes (D-Tx), and 6 patients without type 2 diabetes (Tx) were studied by means of 1) an oral glucose tolerance test (OGTT) to assess the beta-cell secretory response, 2) a euglycemic-hyperinsulinemic (1 mU/[kg.min]) clamp combined with indirect calorimetry and a primed continuous infusion of [6,6-2H2]glucose and [1-13C]leucine to measure postabsorptive and insulin-stimulated carbohydrate and protein metabolism, and 3) 1H-NMR spectroscopy of the calf muscles to measure intramyocellular triglyceride (IMCL) content. The patients were selected from 480 transplant patients in whom there was a 6% prevalence of type 2 diabetes. Five healthy subjects matched for anthropometric parameters served as control subjects (CON). RESULTS: Tx had postabsorptive and insulin-stimulated glucose, leucine, and free fatty acid metabolism, as well as IMCL content, similar to that of CON. D-Tx were characterized by a reduced secretory response during the OGTT and peripheral insulin resistance with respect to glucose metabolism, which was paralleled by increased plasma free fatty acid concentrations and IMCL content. A defective insulin-dependent suppression of the endogenous leucine flux (index of proteolysis) was also evident during the clamp in D-Tx. CONCLUSIONS: Heart transplantation, notwithstanding the immunosuppressive therapy, was characterized by a normal postabsorptive and insulin-stimulated glucose, leucine, and free fatty acid metabolism in Tx. In contrast, insulin resistance with respect to glucose, free fatty acids, and protein metabolism was present in D-Tx regardless of whether diabetes was preexisting or consequent to heart transplantation.

Lymphomas occurring late after solid-organ transplantation: influence of treatment on the clinical outcome.

BACKGROUND: Posttransplant lymphoproliferative disorders (PTLDs) that occur late after solid-organ transplantation are usually a monoclonal proliferation frequently characterized by the lack of the Epstein-Barr virus genome in tumor cells. The clinical outcome and the best management for patients who present with late PTLDs still remain unclear. PATIENTS AND METHODS: Thirty patients who developed PTLDs more than 12 months (range 13-156) after heart, kidney, or liver transplantation were retrospectively evaluated. Median age was 36.7 years (range 1-70). Fifty-five percent of patients presented with advanced-stage (III-IV) lymphoma, 43% of patients presented with B symptoms, and 40% of patients showed extranodal involvement. Twenty-four cases (75%) were categorized as monoclonal monomorphic PTLD. RESULTS: Three patients died of progressive multiorgan failure before any treatment was initiated. Overall, 17 (63%) patients obtained a clinical response (14 patients had complete remission [CR] and 3 patients had partial remission [PR]). Eight (47%) patients are still alive and in CR, two (12%) patients died in CR, and seven (41%) patients relapsed. With a median follow-up of 6 months (range 0.5-42.8), the median overall survival was 6.2 months. Both clinical response and survival were significantly influenced by the treatment. Indeed, all patients treated for limited disease with surgery or radiotherapy in combination with modulation of immunosuppression obtained CR and are still alive and in CR. On the contrary, 33% of patients who received chemotherapy obtained a clinical response, whereas 15% of patients who received chemotherapy showed progressive disease and 50% of patients who received chemotherapy died of toxicity (infectious or multiorgan failure). CONCLUSIONS: We suggest that patients with late PTLDs and limited disease may benefit from local treatment. For patients who require chemotherapy, we suggest that it should be administered to minimize the risk of infection complications.

Heart transplantation in patients with previous Fontan operations.

OBJECTIVE: The clinical features and outcomes of patients undergoing heart transplantation after a failed Fontan operation are still debated. The aim of this study was to retrospectively evaluate our experience in 14 patients undergoing heart transplantation after previous Fontan-type operations. METHODS: From 1990 to 2002, 14 patients underwent heart transplantation in our institution after a previous Fontan procedure. The mean age at the time of the Fontan operation and at transplantation was 7.3 +/- 2.8 and 17.2 +/- 6.3 years, respectively. The indication for transplantation was protein-losing enteropathy in 7 patients, arrhythmia with ventricular dysfunction in 5 patients, and heart failure in 2 patients. All patients received basic immunosuppressive therapy with cyclosporine (INN: ciclosporin) and azathioprine without induction therapy or maintenance steroids. RESULTS: Two hospital deaths occurred: one patient died on the fifth postoperative day of graft failure, and the second died on the 17th postoperative day after an acute neurologic event. Two patients died later, one 23 months after transplantation of acute rejection and the other after 90 months of chronic rejection and endocarditis. One patient underwent successful reintervention 2 years after heart transplantation for pulmonary vein obstruction. The 10 surviving patients are in New York Heart Association class I, with a mean follow-up of 64.5 +/- 42 months. One of them was delivered of a healthy baby 5 years after transplantation. Patients with protein-losing enteropathy reached a normal protein level within a mean of 10 months (range, 6-18 months) after transplantation. Four patients required a temporary administration (3-6 months) of oral steroid therapy for recurrent rejection episodes. Currently, 7 patients are taking cyclosporine, and 3 are taking cyclosporine and azathioprine. The actuarial survival at 1, 5, and 10 years was 86% +/- 9%, 77% +/- 12%, and 62% +/- 17%, respectively. CONCLUSION: Heart transplantation is a good option for patients with a failing Fontan operation. We documented the reversibility of protein-losing enteropathy in all patients. No mortality caused by surgical complications was observed.

Concordance among pathologists in the second Cardiac Allograft Rejection Gene Expression Observational Study (CARGO II).

BACKGROUND: There has been no large evaluation of the ISHLT 2004 acute cellular rejection grading scheme for heart graft endomyocardial biopsy specimens (EMBs). METHODS: We evaluated agreement within the CARGO II pathology panel and between the panel (acting by majority) and the collaborating centers (treated as a single entity), regarding the ISHLT grades of 937 EMBs (with all grades ≥2R merged because of small numbers). RESULTS: Overall all-grade agreement was almost 71% both within the panel and between the panel and the collaborating centers but, in both cases, was largely because of agreement on grade 0: for the average pair of pathologists, fewer than a third of the EMBs assigned grade ≥2R by at least one were assigned this grade by both. CONCLUSION: The 2004 revision has done little to improve agreement on the higher ISHLT grades. An EMB grade ≥2R is not by itself sufficient as a basis for clinical decisions or as a research criterion. Steps should be taken toward greater uniformity in EMB grading, and efforts should be made to replace the ISHLT classification with diagnostic criteria--EMB based or otherwise--that correspond better with the pathophysiology of the transplanted heart.

Heart transplantation with donor-specific antibodies directed toward denatured HLA-A*02:01: a case report.

The development of solid-phase assays for antibody detection has aided in the frequent detection of human leukocyte antigen (HLA) antibodies in nonalloimmunized males. Some scientists have reported that these HLA antibodies are produced to pathogens or allergens and the reactivity with HLA coated beads is the result of cross-reactive epitopes. These antibodies may also be directed toward cryptic epitopes exposed on the denatured beads. In this report, we describe the case of a heart transplanted patient who exhibited anti-HLA-A*02:01 donor-specific antibodies detected with a bead-based assay (Luminex) and undetected with the complement-dependent cytotoxicity (CDC) test. Posttransplant monitoring, carried out with CDC and with Luminex on sera from this patient collected at the 2nd, 4th, 8th, and 12th posttransplant weeks and at 1 year confirmed the presence of anti-HLA-A*02:01 in all serum samples. Additional tests carried out with denatured and intact HLA molecules using single antigen beads demonstrated that the antibody was directed toward a cryptic epitope. One year after transplantation the patient is doing well. No sign of antibody-mediated rejection was observed throughout the follow-up. A comprehensive evaluation of the anamnesis and of antibodies is critical to avoid needless exclusion of organ donors.

Incidence and clinical predictors of a subsequent nonmelanoma skin cancer in solid organ transplant recipients with a first nonmelanoma skin cancer: a multicenter cohort study.

OBJECTIVE: To compare the long-term risk of primary nonmelanoma skin cancer (NMSC) and the risk of subsequent NMSC in kidney and heart transplant recipients. DESIGN: Partially retrospective cohort study. SETTING: Two Italian transplantation centers. PATIENTS: The study included 1934 patients: 1476 renal transplant recipients and 458 heart transplant recipients. MAIN OUTCOME MEASURES: Cumulative incidences and risk factors of the first and subsequent NMSCs. RESULTS: Two hundred patients developed a first NMSC after a median follow-up of 6.8 years after transplantation. The 3-year risk of the primary NMSC was 2.1%. Of the 200 patients with a primary NMSC, 91 (45.5%) had a second NMSC after a median follow-up after the first NMSC of 1.4 years (range, 3 months to 10 years). The 3-year risk of a second NMSC was 32.2%, and it was 49 times higher than that in patients with no previous NMSC. In a Cox proportional hazards regression model, age older than 50 years at the time of transplantation and male sex were significantly related to the first NMSC. Occurrence of the subsequent NMSC was not related to any risk factor considered, including sex, age at transplantation, type of transplanted organ, type of immunosuppressive therapy, histologic type of the first NMSC, and time since diagnosis of the first NMSC. Histologic type of the first NMSC strongly predicted the type of the subsequent NMSC. CONCLUSIONS: Development of a first NMSC confers a high risk of a subsequent NMSC in transplant recipients. Intensive long-term dermatologic follow-up of these patients is advisable.

Colchicine-induced toxicity in a heart transplant patient with chronic renal failure.

Introduction. Therapeutic doses of colchicine in patients with renal compromise and cyclosporine therapy may result in increased plasma concentrations of colchicine and colchicine toxicity. Case Report. A 60-year-old heart transplant patient with chronic renal failure and cyclosporine-induced immunosuppression was started on colchicine for suspected gout. Four days later, he developed multi-organ failure with rhabdomyolysis, liver damage, polyneuropathy, and cardiotoxicity. Colchicine intoxication was suspected and plasma levels were 7 ng/mL 36 hours after the sixth dose. Neutropenia with an absolute neutrophil count of 700 cells/mm3 was observed five days after colchicine discontinuation. Drug discontinuation, supportive care, antibiotic therapy for a concurrent infection, and G-CSF administration resulted in recovery and he was discharged from the hospital 3 weeks later. Discussion. Cyclosporine co-administration increases colchicine toxicity by a dual mechanism: cyclosporine inhibits P-glycoprotein resulting in increased intracellular colchicine concentrations and decreased hepatic and renal excretion of the drug and cyclosporine interacts with CYP3A4 to decreases the hepatic elimination of colchicine. On the other hand, colchicine may increase cyclosporine neurotoxicity by an addictive mechanism. Conclusions. Shortterm administration of therapeutic colchicine doses may cause life-threatening side effects in cyclosporine-treated patients with renal failure.

Evaluation of an automated spectrophotometric assay for reactive oxygen metabolites in serum.

The in vivo assessment of free radicals concentration is hampered by their instability and extremely short half-life. The Diacron Reactive Oxygen Metabolites (D-ROM) test is a recently introduced method to evaluate the peroxidation of organic compounds. Since the manual performance of the test provides excessive analytical imprecision, the aim of this study was to evaluate the automation of this test. Within- and between-run imprecision and interference were assessed according to the guidelines proposed by the NCCLS. The reactive oxygen metabolites' (ROM) stability was evaluated in different physical conditions. For within-run and between-run imprecision the coefficients of variation were consistently lower than 5%. The maximum allowable concentration was 28.2 mmol/l, 0.068 mmol/l and 171 mmol/l for triglycerides, haemoglobin and bilirubin, respectively. Serum storage at -20 degrees C provided adequate ROM stability for up to 3 months, whereas storage at 4 degrees C yielded non-reproducible results. In conclusion, our data provide evidence that the D-ROM assay has both an acceptable stability and an adequate imprecision. The automated assay may be regarded as a fast and reproducible method for the quantitative evaluation of oxidative stress. Since it is easily performed, the method is suitable for routine in clinical laboratories and may provide an accurate estimation of oxidative stress in vivo.

Age-related heart rate response to exercise in heart transplant recipients. Functional significance.

The heart rate (HR) and O(2) uptake (VO(2)) responses to cycle ergometer exercise and the role of O(2) transport in limiting submaximal and maximal aerobic performance were assessed in 33 heart transplant recipients (HTR) [14 children (P-HTR), 11 young adults (YA-HTR) and 8 middle-age adults (A-HTR)] and in 28 age-matched control subjects (CTL). In 7 P-HTR ("responders") the HR response to the onset of exercise (on-response) was as fast as that of CTL, whereas in all other patients ("non-responders") the HR on-response was typical of the denervated heart. Compared with non-responder P-HTR, responder P-HTR were also characterized by a normal peak HR (177+/- 16 vs. 151+/- 25 beats/min), an equally slow time constant for the VO(2) on-response (tau: 54 +/- 11 vs. 62+/- 13 s) and a similar low (approximately 60% of that of CTL) peak VO(2) (28 +/- 7 vs. 26 +/- 10 ml/kg per min). On the other hand non-responder YA-HTR and A-HTR were characterized by a relatively low peak HR (151 +/- 21 and 144 +/- 29 beats/min, respectively), a slow tau for the on-response (63 +/- 12 and 70 +/- 11 s) and a low peak (28 +/- 7 and 19 +/- 6 ml/kg per min). In conclusion, a sizeable number of paediatric patients (responder P-HTR) may reacquire the normal HR response to exercise, both in terms of kinetics and maximal level. Despite the almost complete recovery of cardiovascular function, and, probably, oxygen delivery, both the kinetics of the VO(2) on-response and the maximal aerobic power of the responder P-HTR were similar to those of non-responder P-HTR. The latter finding is probably attributable to peripheral limitations, due to inborn and/or pharmacological muscle deterioration.

The heart rate response to exercise and circulating catecholamines in heart transplant recipients.

The plasma concentration of noradrenaline ([NA]) is higher than that of adrenaline ([A]) both in normal subjects and in heart transplant recipients (HTR). Since in both groups the myocardial density of beta1-adrenergenic receptors is much greater than that of beta2-adrenergenic receptors, the chronotropic response of a denervated heart to changes in plasma [NA] and [A] in the absence of reinnervation should be similar to that of agonist stimulation of beta1-receptors. To test this hypothesis, 17 HTR and 9 healthy subjects (CTL) performed incremental exercise on a cycle ergometer to voluntary exhaustion. Heart rate (HR) was recorded by electrocardiography. [NA] and [A] were measured by high-pressure liquid chromatography at rest and at increasing workloads (w). In both groups, HR and [NA+A] increased with w, and HR with [NA+A]. Normalized HR values, plotted against the logarithm of [NA+A], fitted significantly logistic curves. The affinity constants were different, i.e. 2599+/-350 and 487+/-37 ng.l(-1), for HTR and CTL, respectively. The chronotropic effect of changes in [NA+A] in HTR was similar to that of combined beta1- and beta2-adrenergic activation evoked by applying isoprenaline to isolated heart myocytes (Brodde OE, Pharmacol Ther 60:405-430, 1993). These findings suggest that over time sympathetic reinnervation and the modulation of beta-receptors may take place in HTR, ruling out the hypothesis of persistent heart denervation.

Infusion of autologous Epstein-Barr virus (EBV)-specific cytotoxic T cells for prevention of EBV-related lymphoproliferative disorder in solid organ transplant recipients with evidence of active virus replication.

Epstein-Barr virus (EBV)-associated posttransplantation lymphoproliferative disorders (PTLDs) are a well-recognized complication of immunosuppression in solid organ transplant recipients. The reported therapeutic approaches are frequently complicated by rejection, toxicity, and other infectious pathologies, and overall mortality in patients with unresponsive PTLD remains high. Thus, low-toxicity treatment options or, preferably, some form of prophylactic/preemptive intervention are warranted to improve PTLD outcome in this setting. We assessed whether transfer of EBV-specific cytotoxic T lymphocytes (CTLs) generated in vitro from the peripheral blood of allograft recipients receiving immunosuppression could increase EBV-specific killing in vivo without augmenting the probability of graft rejection. Autologous EBV-specific CTLs were generated for 23 patients who were identified as being at risk of developing PTLD through the finding of elevated EBV DNA load. Of the 23 patients, 7 received 1 to 5 infusions of EBV-specific CTLs. CTL transfer was well tolerated, and none of the patients showed any evidence of rejection. An increase of the EBV-specific cytotoxicity was observed after infusion, notwithstanding continuation of immunosuppressive therapy. EBV DNA levels had a 1.5- to 3-log decrease in 5 patients, whereas in the other 2 graft recipients CTL transfer had no apparent stable effect on EBV load. Our data suggest that the infusion of autologous EBV-specific CTLs obtained from peripheral blood mononuclear cells recovered at the time of viral reactivation is able to augment virus-specific immune response and to reduce viral load in organ transplant recipients. This approach may, therefore, be safely used as prophylaxis of EBV-related lymphoproliferative disorders in these patients, following a strategy of preemptive therapy guided by EBV DNA levels.