Balk Ah

The detection of cytotoxic T cells with high-affinity receptors for donor antigens in the transplanted heart as a prognostic factor for graft rejection

Alloreactive T lymphocytes are the initiators and effectors of acute rejection of organ transplants, and T cells with high-affinity receptors for antigen might be especially implicated in this process. It has been shown that the cytotoxic capacity of CTL with low affinity for alloantigens can be inhibited with CD8 mAb, while high-affinity CTL are not affected. To investigate whether the presence of such high-affinity cells in human heart transplants may be predictive for acute rejection, we analyzed their frequency in cultures derived from endomyocardial biopsies in 19 patients, 9 of whom had never experienced acute rejection and 10 who had had one or more rejection episodes. IN the rejectors, already before histological signs of rejection (myocyte damage) had developed, significantly higher donor-reactive CTL frequencies were found compared with the nonrejectors (medians of 10,586 vs 1,169 reactive cells per 10(6) tested cells, P = 0.002). After CD8 inhibition, the difference between rejectors and nonrejectors was even more pronounced (P < 0.001). In patients with rejection, the number of CD8-resistant, high-affinity CTL was higher than 1000 per million cells in all cases, while in patients who had never experienced rejection this number was less than 1000. As these CTL characteristics are already present before the first histological signs of rejection have developed, this might be used as a prognostic factors.

Four-year follow-up of treatment with intramyocardial skeletal myoblasts injection in patients with ischaemic cardiomyopathy

AIMS Studies reporting improved left ventricular (LV) function of percutaneous skeletal myoblast (SkM) injection in patients with ischaemic cardiomyopathy had follow-up not exceeding 12 months, and did not include a control group. Our group has reported evidence for myoblast efficacy in the first five out of the 14 treated patients. The objective of the present evaluation was to assess if these effects were sustained at long-term follow-up. We compared function of patients treated with SkM 4 years earlier with a matched control group. Secondary endpoints included mortality, NYHA class, N-terminal pro-B-natriuretic peptide levels, incidence of arrhythmias, and quality of life. METHODS AND RESULTS Fourteen patients with ischaemic cardiomyopathy who underwent SkM injection were compared with 28 non-randomized control patients matched for age, sex, location, and extent of myocardial infarction. Contrast echocardiography and tissue Doppler imaging (TDI) was performed to compare global and regional LV function. At 4-year follow-up, three patients (21%) had died in the treated group and 11 patients (39%) in the control group (P = 0.8). In the survivors, LV ejection fraction (EF) was 35 +/- 10% and 37 +/- 9% in the SkM group and 36 +/- 8% and 36 +/- 6% in the controls at baseline and 4 years follow-up, respectively (P = 0.96 between groups at follow-up). TDI-derived systolic velocity in the injected sites was 5.4 +/- 1.8 cm/s in the SkM group when compared with 5.1 +/- 1.6 cm/s in corresponding sites in the control group (P = 0.47). None of the secondary endpoints showed a difference between the groups. However, in the patients fitted with an internal cardioverter defibrillator, more arrhythmias leading to interventions occurred in the treated group than in the control group, 87% and 13%, respectively (P = 0.015). CONCLUSION Percutaneous intramyocardial SkM injection in ischaemic cardiomyopathy has no sustained positive effect on resting global or regional LV function, respectively, at 4-year follow-up. Moreover, the procedure may induce a higher risk of developing serious arrhythmias, but larger patient series are required before more precise characterization of the safety and efficacy profile of the procedure is possible.

FUNCTIONAL RESPONSES OF T CELLS BLOCKED BY ANTI-CD25 ANTIBODY THERAPY DURING CARDIAC REJECTION

BACKGROUND Despite anti-CD25 (interleukin [IL]-2 receptor alpha chain) monoclonal antibody (mAb) therapy, rejection can still occur. T-cell activation through the IL-2 receptor beta and gamma chains by IL-2 or other growth factors may contribute to this rejection. Recently, we have demonstrated that the T-cell growth factor IL-15 was abundantly present in rejecting cardiac grafts during anti-CD25 mAb treatment. METHODS To test whether IL-2- and IL-15-responsive T cells play an active role in rejection during anti-CD25 mAb therapy, we measured the frequency of IL-2- and IL-15-proliferative T cells in peripheral blood from treated patients during rejection (n=12). Measurements were made by limiting dilution analysis in the absence and presence of extra in vitro-added mouse anti-human CD25 mAb. RESULTS In the absence of anti-CD25 mAb, the frequencies of peripheral T cells responding to recombinant human (rh)IL-2 and rhIL-15 from patients were lower than those measured in samples of healthy controls (n=7): median of IL-2-responding T cells 78 per 10(6) (range 31-210 per 10(6)) vs. 154 per 10(6) (122-484 per 10(6), P=0.008) and median of IL-15-responding T cells 62 per 10(6) (range 19-207 per 10(6)) vs. 129 per 10(6) (range 79-192 per 10(6), P=0.02), respectively. In the presence of extra in vitro-added anti-CD25 mAb, frequencies of IL-2-responding T cells from patients significantly decreased, although a considerable number of T cells still proliferated on rhIL-2 (median 85%, range 46-100%). In contrast, the frequencies of IL-15 T cells still responding remained stable (median 2%, range 0-50%, P<0.001). CONCLUSIONS Treatment with anti-CD25 mAbs cannot provide complete suppression of T-cell function because significant numbers of IL-2- and IL-15-responsive T cells remain present in the peripheral blood of allograft recipients during anti-CD25 mAb treatment.

Compliance with the medical regimen and partner's quality of life after heart transplantation

The authors investigated 40 heart transplant recipients and their partners to determine both the partners quality of life upon transplantation and the experiences of both patient and partner with compliance with the medical regimen. Data on sleep disturbances, social isolation, emotional reactions, depression, anxiety, partners apprehension, social support and compliance (regarding behaviour and emotional experience) were obtained approximately 21 months after transplantation. Compared to related study groups, partners did not experience more problems in sleep, social isolation, emotional reactions, depression and anxiety. Patients overestimated the apprehension of their partners significantly (p<0.0001). Generally speaking, with the exception of three items relating to eating fish, canned food and forgetfulness in medicine intake, patients and partners agreed with respect to actual compliance behaviour. Lowest compliance concerned regular physical exercise: 28%. Both patient and partner insisted that they had scarcely any emotional problem with the regimen. Further systematic research is needed to bring to light factors that affect compliance as well as adequate methods to bring about an improvement therein.

Performance of the Seattle Heart Failure Model in Implantable Defibrillator Patients Treated With Cardiac Resynchronization Therapy

The Seattle Heart Failure Model (SHFM) is a validated multivariate risk prediction model for mortality in patients with heart failure, using widely available clinical variables. The aim of this study was to assess the performance of the SHFM when applied to patients with heart failure who received cardiac resynchronization therapy devices with defibrillation. A total of 413 patients were identified from 2 prospective implantable cardioverter-defibrillator registries who received cardiac resynchronization therapy devices with defibrillation for the primary prevention of sudden death. Baseline laboratory and clinical data were entered in the SHFM to calculate predicted survival. The end point was all-cause mortality. During a median follow-up period of 2.8 years, 78 patients died and 9 underwent heart transplantation. Observed versus predicted 5-year mortality rates were 11.6% versus 11.4%, 21.5% versus 22.1%, and 41.4% versus 46.1% by ascending tertile of Seattle Heart Failure Score, respectively. No systematic or substantial errors of risk estimation were observed. Discrimination was excellent; the C-statistic ranged from 0.78 at 1-year follow-up to 0.70 at 5-year follow-up, and the Hosmer-Lemeshow chi-square statistic was 0.87 (p = 0.65). In conclusion, in patients with heart failure who received cardiac resynchronization therapy devices with defibrillation, the SHFM offers adequate discrimination of risk for all-cause mortality and estimation of mortality risk without substantial or systematic errors.

Prediction of Appropriate Defibrillator Therapy in Heart Failure Patients Treated With Cardiac Resynchronization Therapy

The necessity of implantable cardioverter-defibrillator (ICD) implantation in patients with systolic heart failure (HF) who undergo cardiac resynchronization therapy (CRT) may be questioned. The aim of this study was to identify patients at low risk for sustained ventricular arrhythmia. One hundred sixty-nine consecutive patients with HF (mean age 60 +/- 12 years, 125 men, 73% in New York Heart Association class III) referred for CRT and prophylactic, primary prevention ICD implantation underwent baseline clinical and echocardiographic assessment and regular device follow-up. The primary study end point was appropriate ICD therapy. During a mean follow-up period of 654 +/- 394 days, 35 patients (21%) had sustained ventricular arrhythmias requiring appropriate ICD therapy. Of the 3 patients who experienced sudden cardiac death, 2 had been treated with appropriate ICD therapy before sudden cardiac death. In a multivariate model, only history of nonsustained ventricular tachycardia (p = 0.001), a severely (<20%) decreased left ventricular ejection fraction (p = 0.001), and digitalis therapy (p = 0.08) independently predicted appropriate ICD therapy. Patients with 0 (n = 46), 1 (n = 36), 2 (n = 73), and 3 (n = 14) risk factors for appropriate ICD therapy had a 7%, 14%, 27%, and 64% and 0%, 6%, 10%, and 43% incidence of appropriate ICD therapy for ventricular arrhythmias and for rapid ventricular tachycardia or ventricular fibrillation, respectively. In conclusion, apart from commonsense considerations (age and significant co-morbidities), ICD addition seems ineffective in CRT patients without nonsustained ventricular tachycardia, digoxin therapy, and severely reduced left ventricular systolic function.

Intragraft interleukin 2 mRNA expression during acute cellular rejection and left ventricular total wall thickness after heart transplantation

Objective: To assess whether diastolic graft function is influenced by intragraft interleukin 2 (IL-2) messenger RNA (mRNA) expression in rejecting cardiac allografts. Design: 16 recipients of cardiac allografts were monitored during the first three months after transplantation. The presence of IL-2 mRNA in endomyocardial biopsies (n = 123) was measured by reverse transcriptase polymerase chain reaction. To determine heart function, concurrent M mode and two dimensional Doppler echocardiograms were analysed. Results: Histological signs of acute rejection (International Society for Heart and Lung Transplantation (ISHLT) rejection grade > 2) were strongly associated with IL-2 mRNA expression (IL-2 mRNA was present in 12 of 20 endomyocardial biopsies (60%) with acute rejection and in 24 of 103 endomyocardial biopsies (23%) without acute rejection, p = 0.002). No significant relation was found between either histology or IL-2 mRNA expression alone and the studied echocardiographic parameters. However, stratification of the echocardiographic data into those of patients with and those without acute rejection showed that during acute rejection IL-2 mRNA expression was significantly associated with increased left ventricular total wall thickness (mean change in total wall thickness was +0.22 cm in patients with IL-2 mRNA expression versus −0.18 cm in patients without IL-2 mRNA expression, p = 0.048). Conclusions: An increase in left ventricular total wall thickness precedes IL-2 positive acute rejection after heart transplantation. Thus, cardiac allograft rejection accompanied by intragraft IL-2 mRNA expression may be indicative of more severe rejection episodes.

Cytokine gene expression profiles in human endomyocardial biopsy (EMB) derived lymphocyte cultures and in EMB tissue

Abstract The reverse transcriptase polymerase chain reaction (RT‐PCR) technique was used to analyse cytokine gene expression in relation to acute cardiac rejection. Expression of interleukins, IL‐2, IL‐4, IL‐6 and IL‐10 mRNA was studied in sequential endomyocardial biopsies (EMB) and in graft‐infiltrating lymphocyte (GIL) cultures propagated from EMB taken after heart transplantation. The cytokine gene expression of GIL propagated from EMB taken during an episode of rejection and of immunological quiescence was comparable. In contrast, posttransplant EMB showed selective IL‐2 gene expression when rejection was diagnosed. IL‐4 mRNA was absent in pretransplant EMB but present in posttransplant EMB taken during periods of rejection and of immunological quiescence. Both IL‐6 and IL‐10 transcripts were found in pre‐ and posttransplant EMB. These findings confirmed that IL‐2 is specifically involved in cardiac rejection, while IL‐4 may play a role in immune responses leading to graft rejection or graft tolerance.

Effect of adopting a new histological grading system of acute rejection after heart transplantation

Background Treatment policy of acute rejection after heart transplantation has been changed after adopting the ISHLT endomyocardial biopsy grading system in 1991. Objective To determine the effect of this policy change on clinical outcome after transplantation. Methods The outcome of 147 patients who had a transplant before (early group, median follow up 96 months) and 114 patients who had a transplant after (late group, median follow up 41 months) the introduction of the ISHLT biopsy grading system was studied retrospectively. Initially “moderate rejection” according to Billingham’s conventional criteria was treated. From January 1991 grade 3A and higher was considered to require intensification of immunosuppression. Results There were some differences between the two groups: recipients (50 v 44 years) as well as donors (28 v 24 years) were older in the “late group” and more patients of this group received early anti-T cell prophylaxis (92% v 56%). Despite more extensive use of early prophylaxis more rejection episodes were diagnosed (2.4 v1.4) and considerably more courses of rejection treatment were instituted in the late compared with the early group (3.2v 1.5). There were no deaths because of rejection in the late group, however, more infections occurred within the first year (mean 1.8 v 1.4) and more non-skin malignancies within the first 41 months were diagnosed (8 of 57 v 6 of 147, 95% CIs of difference includes 0). The incidence of graft vascular disease in the late group has been comparable to the early group until now. Conclusion The interpretation of the ISHLT grading system resulted in lowering of the threshold for the diagnosis of rejection thereby increasing the number of rejections and subsequently the immunosuppressive load and its complications.

Intragraft mrna expression of the novel cytokine IL-21 during acute rejection after clinical heart transplantation

phage (CD11b ) infiltration and significantly elevated intragraft mRNA expression of iNOS. During the development of transplant arteriosclerosis (TxA) PECAM-1-/donor endothelial cells were replaced by recipient PECAM-1 / endothelial cells, a process that occurred only in the allogeneic situation. Endothelial replacement commenced 14 days after transplantation and was complete by day 30. Conclusion: PECAM-1 expression by donor endothelial cells may regulate macrophage infiltration into the graft thereby controlling the development of TxA. Furthermore, these data suggest that the alloantigen specificity of the effector cells that mediate endothelial cell destruction may change as the rejection process progresses. Initially cells responding to donor antigens via the direct pathway of allorecognition will play a key role, but later in the response, indirect pathway T cells will become increasingly important.