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Previously, we demonstrated in heart transplant patients that FOXP3, a gene required for the development and function of regulatory T cells, was highly expressed in the graft during an acute cellular rejection. In this study, we analyzed whether the FOXP3 gene expression in the peripheral blood also reflects anti-donor immune responses, and therefore may provide clues for non-invasive detection of non-responsiveness or acute rejection. We examined the FOXP3 expression patterns of peripheral blood mononuclear cells (PBMC; n=69) of 19 heart transplant patients during quiescence and rejection in comparison with those of endomyocardial biopsies (EMB; n=75) of 24 heart transplant patients. While the FOXP3 mRNA levels were abundantly expressed in rejecting EMB (ISHLT rejection grade>1R) compared with EMB without histological evidence of myocardial damage (ISHLT rejection grade 0R-1R; p=0.003), no association with rejection or non-responsiveness was found for the FOXP3 mRNA levels in the peripheral blood. Thus, in contrast to intragraft FOXP3 gene expression, the peripheral FOXP3 mRNA levels lack correlation with anti-donor immune responses in the graft, and, consequently, FOXP3 does not appear to be a potential candidate gene for non-invasive diagnosis of non-responsiveness or rejection.

Background: Regulatory FOXP3+ T cells control immune responses of effector T cells. However, whether these cells regulate antidonor responses in the graft of cardiac allograft patients is unknown. Therefore, we analyzed the gene expression profiles of regulatory and effector T-cell markers during immunological quiescence and acute rejection., Methods: Quantitative real-time polymerase chain reaction was used to analyze mRNA expression levels in time-zero specimens (n=24) and endomyocardial biopsies (EMB; n=72) of cardiac allograft patients who remained free from rejection (nonrejectors; n=12) and patients with at least one histologically proven acute rejection episode (rejectors; International Society for Heart and Lung Transplantation [ISHLT] rejection grade>2; n=12)., Results: For all analyzed regulatory and effector T-cell markers, mRNA expression levels were increased in biopsies taken after heart transplantation compared with those in time-zero specimens. Posttransplantation, the FOXP3 mRNA levels were higher in EMB assigned to a higher ISHLT rejection grade than the biopsies with grade 0: the highest mRNA levels were detected in the rejection biopsies (rejection grade>2; P=0.003). In addition, the mRNA levels of CD25, glucocorticoid-induced TNF receptor family-related gene, cytotoxic T lymphocyte-associated antigen 4, interleukin-2, and granzyme B were also significantly higher in rejecting EMB than in nonrejecting EMB (rejection grade

Background: Interleukin (IL)-21 is the most recently described cytokine that signals via the common cytokine receptor (gammac), is produced by activated CD4+ T-cells, and regulates expansion and effector function of CD8+ T-cells., Materials: To explore the actions of IL-21 with other gammac-dependent cytokines in alloreactivity, mRNA expression of IL-21, IL-21R alpha-chain, and IL-2 proliferation and cytotoxicity was measured after stimulation in mixed lymphocyte reactions. Additionally, IL-21 and IL-21R alpha-chain expression was studied in biopsies of heart transplant patients., Results: Analysis of mRNA expression levels of allostimulated T-cells showed a 10-fold induction of IL-21 and IL-21R alpha-chain. Interestingly, induction of IL-21 was highly dependent on IL-2 (as in the presence of anti-IL-2, anti-IL-2R alpha-chain, and the immunosuppressive drugs cyclosporine A, tacrolimus, and rapamycin) the transcription of IL-21 was almost completely inhibited, whereas in the presence of exogenous IL-2 the mRNA expression of IL-21 was even more upregulated. IL-21 functioned as a costimulator for IL-2 to augment proliferation and cytotoxic responses, while blockade of the IL-2 route abrogated these functions of IL-21. Blockade of the IL-21 route by anti-IL-21R alpha-chain monoclonal antibodies inhibited the proliferation of alloactivated T-cells. Also, in vivo alloreactivity was associated with IL-21/IL-21R alpha-chain expression. After heart transplantation, the highest intragraft IL-21, IL-21R alpha-chain, and IL-2 mRNA expression levels were measured during acute rejection (P<0.001, P=0.01, P=0.03)., Conclusion: IL-21 is a critical cytokine for IL-2 dependent immune processes. Blockade of the IL-21 pathway may provide a new perspective for the treatment of allogeneic responses in patients after transplantation.

Allo-Ag presentation to Ag-specific T-lymphocytes by donor or recipient dendritic cells (DCs) induces acute rejection (AR) after solid organ transplantation. It is postulated that myeloid (mDC) and plasmacytoid (pDC) subsets circulate differentially between bone marrow, heart and lymphoid tissues after cardiac transplantation (HTx). We investigated peripheral blood DC subset distribution, maturation and lymphoid homing properties in relation to endomyocardial biopsy (EMB) rejection grade after clinical HTx. Twenty-one HTx recipients under standard immunosuppression were studied in a 9-month follow-up. mDC and pDC numbers were analyzed by flow cytometry in fresh venous whole blood samples collected during the EMB procedures and before histological diagnosis of AR. Subsets were further characterized for maturation marker CD83 and lymphoid homing chemokine receptor CCR7. Although numbers of both DC subsets remained low for the whole post-HTx period, we observed a negative association of mDCs with rejection grade. Repeated measurements analysis revealed that only mDCs decreased during AR episodes. Rejectors had lower mDC numbers after a 3-month follow-up compared to nonrejectors. Furthermore, patients during AR exhibited low proportions of mDCs positive for CD83 or CCR7. These findings suggest peripheral blood mDC depletion in association with selective lymphoid homing of this subset during AR after clinical HTx.

Introduction: In vitro studies have shown that apoptotic cell death is triggered by a IL-2-dependent activation of the Fas-FasL pathway and that this pathway can be inhibited by FLIP., Methods: To define whether FLIP regulates apoptotic death of graft infiltrating T-cells during IL-2-mediated rejection, we analyzed endomyocardial biopsies (EMB) from cardiac allograft recipients for CD3, DNA strand breaks (TUNEL assay), FLIP (mRNA and protein), and FasL mRNA expression., Results: Apoptosis was present in CD3+ T-cell infiltrates. The number of TUNEL-stained mononuclear cells was inversely correlated with FLIP mRNA expression levels (P=.09). FLIP protein was present in 5% to 10% of the infiltrating cells and was constitutively produced by cardiomyocytes irrespective of the rejection grade. Rejection biopsies had elevated IL-2 and FasL mRNA expression levels compared to the expression levels before and after acute rejection (P=.03 and P=.11), while FLIP mRNA expression levels were significantly decreased during rejection (P=.05)., Conclusion: Our results indicate that during the IL-2-induced rejection process, infiltrated T cells become more sensitive to apoptosis.

Peri-operative tissue injury triggers the development of Transplant Coronary Artery Disease (TCAD). Animal studies have shown that induction of heme oxygenase (HO)-1 protects the donor organ from the development of TCAD. To investigate the role of HO-1 in TCAD after clinical heart transplantation, we measured intragraft mRNA expression of HO-1, HIF-1alpha, TGF-beta, FLIP, and the Bcl-2/Bax balance. Immunohistochemical staining of HO-1 was performed to determine its origin. Myocardial biopsies taken at the end of the transplantation procedure (time 0), at 1 week and at 10 months after transplantation were studied from recipients with or without angiographic signs of accelerated TCAD, diagnosed after 1 year. At time 0, no differences in mRNA expression for any of the measured parameters were found between TCAD positive and negative patients. At 1 week, mRNA expression of HO-1 and TGF-beta was higher in grafts that developed accelerated TCAD (p=0.001 and p=0.0002). These higher mRNA levels were accompanied by a pro-apoptotic shift in Bcl-2/Bax (p=0.02), suggesting proneness for apoptosis via the mitochondrial pathway. Immunohistochemical staining showed that HO-1 was mainly produced by infiltrating macrophages. At 10 months, again HO-1 and TGF-beta levels were high in TCAD positive patients (p=0.02 and p=0.05), but the expression of apoptotic markers was comparable at this time point. Our results suggest that a higher HO-1 by macrophages in our patient population might be an adaptive response to tissue injury and inflammation, reflecting damage due to the transplantation procedure that finally results in TCAD.

Background: To define whether immunosuppressive agents that block the interleukin (IL)-2 pathway could prevent activation-induced cell death of activated T cells in the graft, we measured expression of IL-2, IL-2 receptor alpha chain (CD25), IL-15, Fas, and Fas ligand by real time reverse transcription-polymerase chain reaction in cardiac allografts., Methods: We characterized the phenotype of the infiltrating cells (CD3, CD68, CD25) by immunohistochemistry. The proportion of apoptotic graft-infiltrating cells was determined by TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) staining. We analyzed endomyocardial biopsy specimens from cardiac allograft recipients who were treated with anti-CD25 monoclonal antibody (mAb) induction therapy (daclizumab) or with matching placebo in combination with cyclosporine, steroids, and mycophenolate mofetil., Results: Treatment with anti-CD25 mAb affected the number of infiltrating CD3 and CD68 cells and the IL-2-regulated apoptotic pathway. During anti-CD25 mAb treatment, significantly lower intragraft IL-2 and CD25 mRNA transcription levels and decreased numbers of CD25+ T cells were found compared with the levels measured in endomyocardial biopsy specimens from placebo-treated patients (5- to 10-fold, P=0.002 and P<0.0001, respectively). In these samples the intragraft mRNA expression levels of IL-15 were also lower (P=0.02). Inhibition of the IL-2 pathway by anti-CD25 mAb therapy was accompanied by reduced mRNA and protein of Fas ligand and not by reduced Fas expression (P=0.001 and P=0.03). TUNEL staining revealed that the proportion of graft-infiltrating cells was lower in the anti-CD25 mAb patient group than the proportion of apoptotic cells in patients receiving placebo (P=0.06)., Conclusion: Our data suggest that immunosuppressive agents that affect the IL-2 pathway hinder the mechanism of activation-induced cell death by which the immune system eliminates alloreactive cells.

Because production of immune regulatory proteins may play a role in early graft dysfunction after heart transplantation, we analyzed whether intragraft cytokine messenger RNA (mRNA) expression levels are associated with diastolic left ventricular function in cardiac allografts. We intensively monitored 16 cardiac allograft recipients during the first 3 months after transplantation. The mRNA expression levels of tumor necrosis factor (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1), transforming growth factor (TGF-beta), platelet derived growth factor (PDGF-A), and basic fibroblast growth factor (bFGF) were measured in endomyocardial biopsies (n = 123) by quantitative RT-PCR. To determine diastolic allograft function, concurrent M-mode and two-dimensional Doppler echocardiograms were analyzed for the following parameters: left ventricular total wall thickness, maximal early and atrial mitral flow velocity, deceleration time of maximal early mitral flow velocity, and isovolumetric relaxation period. During the first 3 months post-transplant an overall decrease in mRNA expression levels of almost all measured cytokines was observed, which paralleled an improvement in diastolic left ventricular wall thickness and function. However, no straightforward relationship could be found between a specific cytokine mRNA expression pattern and the studied echocardiographic parameters. Our data suggest that the improvement in diastolic left ventricular function is associated with a general reduction of inflammation within the allograft, rather than related to a specific cytokine expression pattern.

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.

Background: Despite blockade of the interleukin-2/interleukin 2 receptor (IL-2/IL-2R) pathway by the murine anti-CD25 (i.e., IL-2R alpha chain) monoclonal antibody BT563, cardiac rejection can still occur. In these cases, growth factors other than IL-2 may contribute to allograft rejection. We studied the expression of IL-15, a macrophage-derived cytokine associated with T-cell activation, which interacts with the beta and gamma chains of the IL-2R during rejection episodes under anti-CD25 therapy., Methods: We measured intragraft IL-15 mRNA expression and the number of IL-15- and CD68-positive cells in posttransplantation endomyocardial biopsies (EMBs; n=45) and in nontransplanted, donor-heart specimens (n=11) by competitive template reverse transcription-polymerase chain reaction and immunohistochemistry, respectively., Results: IL-15 mRNA expression was present in the majority of posttransplantation EMB specimens (91%, 41/45) and in nontransplanted donor-heart specimens (91%, 10/11). Relative IL-15 mRNA levels were neither associated with transplantation nor with rejection status. After transplantation, the number of IL-15- and CD68-positive cells significantly increased (P<0.001), but IL-15-positive cell counts did not reflect the histological rejection grade. Anti-CD25 treatment, in contrast to its effects on the IL-2/IL-2R complex, had no influence on intragraft IL-15 mRNA and protein production. In rejection EMB specimens, during (n=5) and after (n=8) anti-CD25 therapy, no differences in relative IL-15 mRNA levels, or in IL-15- and CD68-positive cell counts, were measured., Conclusions: After heart transplantation, high numbers of IL-15- and CD68-positive cells infiltrate the graft. This phenomenon is independent of the rejection status. IL-15 remains present during blockade of the IL-2/IL-2R pathway by anti-CD25 monoclonal antibodies, and it may participate in T cell-dependent donor-directed immune responses, thereby explaining the occurrence of rejection in the absence of IL-2.

Background: To determine mechanisms that trigger graft vascular disease (GVD) after heart transplantation, we studied parameters that reflect both early and late intragraft allogeneic reactions., Method: With reverse transcriptase-polymerase chain reaction analysis, mRNA expression of interleukin-2 (IL-2), interleukin-4, interleukin-6, interleukin-10, interferon-gamma, platelet-derived growth factor-alpha, and transforming growth factor-beta was measured in endomyocardial biopsy (EMB) specimens obtained from 34 recipients during the first acute rejection episode (n = 29) or at a comparable time after transplantation for patients without rejection (n = 5) and at time of assessment of GVD by coronary angiography at 1 year (n = 34)., Results: At the time of assessment of GVD, mRNA expression of IL-2, interleukin-4, and interleukin-6 were barely detectable, whereas messenger coding for interferon-gamma, interleukin-10, transforming growth factor-beta, and platelet-derived growth factor-alpha genes were constitutively expressed. Moreover, intragraft mRNA patterns of cytokines and growth factors between patients with GVD (n = 17) or without GVD (n = 17) were comparable. In contrast, during the first acute rejection episode a completely different pattern was found. Development of GVD was associated with IL-2 mRNA expression and not with the other cytokines analyzed. IL-2 mRNA was present in 77% of rejection EMB specimens obtained from patients with GVD versus 33% of the EMB specimens obtained from patients without GVD (p = 0.03) and not detectable in EMB specimens obtained from patients with no rejection. Also nonimmunologic risk factors such as longer ischemia time (median 193 vs 141 minutes; p = 0.002) and higher donor age (median 32 vs 23 years; p = 0.02) were associated with GVD. But no relation was found between these nonimmunologic risk factors and IL-2-positive acute rejections., Conclusions: Nonspecific risk factors and IL-2-positive rejections may independently trigger GVD after clinical heart transplantation.

Background: Anti-interleukin (IL)-2 receptor (IL-2R) antibodies have been used as rejection prophylaxis after organ transplantation. Despite this induction treatment, acute rejections may occur. We wondered whether these rejections developed via the IL-2/IL-2R pathway., Methods: In a prospective trial using BT563, a murine IgG1 anti-IL-2R antibody, for rejection prophylaxis after heart transplantation, 20 patients were treated in combination with cyclosporine from the day of transplantation (group A). As a control group, 31 patients were also treated with BT563, but in these patients, cyclosporine treatment was initiated on day 3 (group B)., Results: Three patients from group A and two patients from group B died in the first postoperative month (of causes not related to acute rejection) and were left out of the analysis of rejection incidence. Freedom from acute rejection at 1 week after transplantation in group A (14/17; 82%) was lower than in group B (16/29; 55%), although the difference did not reach statistical significance. There was no difference in either the number of acute rejection episodes at 12 weeks or the required rejection treatments between groups A and B. Infectious complications were evenly distributed in both groups. Immunohistochemistry showed that during acute rejection, in the presence of circulating BT563, IL-2R-bearing cells were present in only one of five rejection biopsies (20%), whereas these cells were often present (6/8, or 75%) in rejections occurring in the absence of BT563. The presence of BT563 was associated with a similar difference in the mRNA expression of IL-2 (2/5 vs. 6/8)., Conclusions: Apparently, despite adequate blockade of the IL-2/IL-2R pathway, patients may develop acute rejection, reflecting the redundancy of the cytokine network. The ever-present IL-15 may well be a candidate for overtaking the role of IL-2.

Histological examination of endomyocardial biopsy (EMB) is the main technique for rejection surveillance after heart transplantation. This technique is elaborate, inconvenient for the patient, and not without complications. We prospectively analyzed whether the measurement of C-reactive protein (CRP), an acute phase protein that quickly rises when there is inflammation, can serve as a marker for immunological quiescence and as an indicator for withholding EMB. During a 6-month period, CRP was measured in all patients referred for EMB as part of the routine follow-up after heart transplantation. Acute rejection in patients with a follow-up of more than 1 year was rare (1/76). In the majority of cases, EMB was taken within the 1-year post-transplantation (170/246 = 69%). In 71/170 biopsies (42%), CRP was < or = 1; in the other 99/170 (58%), CRP was > or = 2. When CRP was < or = 1, acute rejection was diagnosed in 12/70 cases (17%). In contrast, acute rejection was found in 28/99 cases (28%) with CRP > or = 2 (P = 0.1). Although CRP is elevated more often in the presence of acute rejection, its sensitivity does not allow CRP to replace the routine performance of EMB for monitoring rejection after heart transplantation. We did, however, find a prognostic significance with regard to the effect of rejection treatment: in all acute rejections with a CRP < or = 3 (n = 11), steroids were effective.

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 v 1.4) and considerably more courses of rejection treatment were instituted in the late compared with the early group (3.2 v 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.

Background: Cytokines play an important role in allograft rejection. The local production of cytokines by T-helper 2 cells within an allograft could influence the induction of graft rejection., Methods: Therefore we studied the in vitro production of cytokines by cells infiltrating the graft. graft-infiltrating cell cultures derived from human endomyocardial biopsy specimens more often produced interleukin-2 (p < 0.001), interferon-gamma (p < 0.001), interleukin-4 (p = 0.02), and interleukin-6 (p = 0.04) after stimulation with a B-cell line obtained from the heart donor than after stimulation with a third-party B-cell line. Furthermore, the levels of these cytokines were significantly higher after donor stimulation than after third-party stimulation (p < 0.001)., Results: Within the first 90 days after heart transplantation, significantly higher levels of interleukin-2 (p = 0.050 and interferon-gamma (p = 0.02) were produced by donor-stimulated lymphocyte cultures derived from biopsy specimens taken during a rejection episode compared with cultures from biopsy specimens taken during a period without rejection. After 90 days, the levels of T-helper 1 cytokine (interleukin-2 and interferon-gamma) production were, irrespective of the rejection grade, comparable with those found in the cultures from rejection biopsy specimens taken early after transplantation. With regard to T-helper 2 cytokines (interleukin-4 and interleukin-6), no relation was found with the presence of rejection at any time after transplantation., Conclusions: These data suggest that in the first 3 months after heart transplantation, acute rejection is associated with the production of increased levels of T-helper 1 cytokines but not of T-helper 1 cytokines but not of T-helper 2 cytokines by donor stimulated graft-infiltrating lymphocytes. Thereafter, the T-helper 1 cytokine production of graft-infiltrating lymphocytes remained high, suggesting a continuous state of immunologic activity even in the absence of rejection.

The value of pulsed-wave transmitral Doppler for the diagnosis of moderate acute rejection was examined in a total of 347 Doppler recordings obtained in 32 consecutive cardiac allograft recipients. Serial Doppler examinations (median, 11 per patient; range, 1 to 23) were performed simultaneously with endomyocardial biopsies from the first week after heart transplantation to a follow-up of 186 days (median; range, 10 to 395 days after transplantation). Pulsed-wave transmitral Doppler did not allow noninvasive diagnosis of moderate acute rejection in individual patients. Peak filling rate normalized for mitral stroke volume, early diastolic velocity, and mean diastolic velocity were significantly increased, whereas diastolic filling period was decreased during moderate acute rejection compared to other biopsy classes. The wide overlap of measurements in individual recipients with or without rejection may be due, however, to a variety of hemodynamic factors after transplantation affecting diastolic function, which are superimposed on the restrictive left ventricular filling pattern caused by persistent mild acute rejection and left ventricular hypertrophy. These hemodynamic factors include pulmonary hypertension, perioperative ischemia, reperfusion injury, and changes in both blood pressure and loading conditions caused by hypertension and its treatment. Differences between studies with regard to the detection of moderate acute rejection by transmitral Doppler may be caused by chance, because most studies were relatively small. Differences in methods, patient selection, duration of follow-up, prevalence of hypertension and left ventricular hypertrophy, and differences in antihypertensive drug regimens may also play a role. Furthermore differences in the incidence of mild acute rejection, its treatment, and the type of maintenance immunosuppressive regimen used may have influenced the outcome of these studies considerably.

Recent studies comparing the effects of induction therapy with polyclonal antilymphocyte globulins (ALG) or with monoclonal T-cell-specific antibodies are not unanimous. Therefore, 55 heart recipients were allocated to either 7-day courses of polyclonal ALG (n = 28) or of monoclonal OKT3 (n = 27). Additionally, azathioprine and low dose steroids were given. There were no severe side effects after OKT3; the course of ALG, however, had to be discontinued in 20 patients because of extensive flares. No differences between the two groups were found in freedom from rejection or in the incidence of infection. The 1- and 2-year survival was 96% in both groups. Although monoclonal and polyclonal induction therapies are equally effective for rejection prophylaxis, OKT3 may be preferred because of a lack of important side effects. However, the fact that a shorter course of ALG is equally effective may be in favour of ALG.