S. Celik

IL-10 inhibits endothelium-dependent T cell costimulation by up-regulation of ILT3/4 in human vascular endothelial cells

Effects of IL‐10 on endothelium‐dependent T cell activation have not been investigated in detail. We confirm expression of the IL‐10 receptor and effective signaling via STAT‐3 in human umbilical vein endothelial cells (HUVEC). In CD4 T cell cocultures with HUVEC, pretreatment of endothelial cells with IL‐10 resulted in significant dose‐dependent inhibition of CD4 T cell proliferation, which also occurred when IL‐10 was removed after pretreatment before starting cocultures. Th1/Th2 polarization of proliferated T cells, endothelial nitric oxide (NO), or IL‐12 production were unchanged. However, IL‐10 stimulation resulted in up‐regulation of SOCS‐3, a negative regulator of cytokine secretion, and induction of the inhibitory surface molecules immunoglobulin‐like transcript 3 and 4 (ILT3/ILT4) in EC, potentially involving glucocorticoid‐induced leucine zipper (GILZ). Addition of blocking antibodies against ILT3/ILT4 to EC/T cell cocultures resulted in nearly complete reestablishment of T cell proliferation. In contrast, addition of soluble ILT3 or overexpression of ILT3 in cocultures significantly reduced T cell proliferation. No induction of foxp3+ regulatory T cells was seen. In conclusion, the T cell costimulatory potential of human EC is markedly suppressed by IL‐10 due to up‐regulation of ILT3/ILT4, obviously not involving generation of Treg. This identifies a novel action of IL‐10 in EC and a potential therapeutical target for local immunomodulation.

Increased Adherence after Switch From Twice Daily Calcineurin Inhibitor Based Treatment to Once Daily Modified Released Tacrolimus in Heart Transplantation: A Pre-experimental Study

BACKGROUND Modified release tacrolimus (TAC) is a new, once-daily oral formulation of the established immunosuppressive agent TAC. Simplification of regimen has been associated with better adherence. This study evaluated patient adherence, as well as safety and efficacy among chronic stable heart transplantation (HT) patients switched from a conventional twice daily calcineurin inhibitor-based regimen (TAC or cyclosporine A [CsA]) to (once daily) modified release TAC. METHODS We switched 54 chronic stable patients (41 males and 13 females) from twice daily dosing with conventional TAC or CsA to once daily dosing with modified release TAC. Self-reported adherence was assessed at baseline and at 4 months after the switch using the Basel Assessment of Adherence with Immunosuppressive Medication Scale [BAASIS]), a 4-item validated questionnaire including also a Visual Analogue Scale (VAS). Nonadherence was defined as any self-reported nonadherence on any item. RESULTS Modified release TAC was discontinued in 4 patients because of diarrhea (n = 1) or gastrointestinal discomfort (n = 3) leaving 50 evaluable patients. Overall nonadherence at baseline for any of the 4 items was 74% versus 38% after 4 months (P = .0001). Thereafter, adherence improved in 28 patients (56.0%), was unchanged in 18 (36.0%), and decreased in 4 subjects (8.0%). The VAS score improved from 82.3% ± 2.6% to 97.5% ± 4.8% (P < .0001). No significant changes were observed after 4 months regarding hematologic, renal, or liver function parameters (all P = NS). CONCLUSIONS Therapeutic regimens for transplant recipients are often complex, contributing to a high incidence of medication nonadherence. This study in chronic, stable, heart transplantation patients demonstrated a significant improvement in patient adherence after a switch to modified release TAC, which was generally well tolerated.

Effects of protein A immunoadsorption in patients with chronic dilated cardiomyopathy.

The objective of this study was to investigate functional effects of immunoadsorption (IA) in patients with chronic nonfamilial dilated cardiomyopathy (DCM) regarding clinical and humoral markers of heart failure.

Malignancies After Heart Transplantation: Incidence, Risk Factors, and Effects of Calcineurin Inhibitor Withdrawal

The objectives of the present study were to evaluate the incidence of malignancies and to describe the effects of immunosuppression on survival and recurrence of malignancies after heart transplantation (HTX). Data were analyzed in 211 cardiac allograft recipients, in whom HTX was performed between 1989 and 2005. All of these patients survived for more than 2 years after HTX and received induction therapy with antithymocyte globulin (RATG) guided by T-cell monitoring since 1994. An immunosuppressive regimen consisting of cyclosporine A (CsA) combined with azathioprine was followed by CsA and mycophenolate mofetil (MMF) in 2001; mammalian target of rapamycin (mTOR) inhibitors (everolimus/sirolimus) were used since 2003. Mean patient age at HTX was 51.4 ± 10.5 years; mean follow-up time after HTX 9.2 ± 4.7 years. Overall incidence of neoplasias was 30.8%. Individual risk factors associated with a higher risk of malignancy after HTX were higher age at transplantation (P = .003), male gender (P = .005) and ischemic cardiomyopathy before HTX (P = .04). Administration of azathioprine (P < .0001) or a calcineurin inhibitor (CNI) (P = .02) for more than 1 year was associated with development of malignancy, whereas significantly fewer malignancies were noticed in patients receiving an mTOR-inhibitor (P < .0001). Kaplan-Meier analysis demonstrated a strong statistical trend toward an improved survival in patients with a noncutaneous neoplasia switched to a CNI-free protocol (P = .05). This study demonstrated the impact of a variety of individual risk factors and immunosuppressive drugs on development of malignancy after HTX. Markedly fewer patients with noncutaneous malignancies died after switch to a CNI-free regimen, not quite reaching statistical significance by Kaplan-Meier analysis, however.

Epstein-Barr virus load in whole blood is associated with immunosuppression, but not with post-transplant lymphoproliferative disease in stable adult heart transplant patients

Development of Epstein‐Barr virus (EBV)‐associated post‐transplant lymphoproliferative disease (PTLD) is a serious complication following heart transplantation (HTX). This study investigates EBV DNA load in adult heart transplant recipients, its association with immunosuppression, and its potential as a marker for development of PTLD. EBV DNA load was measured prospectively by quantitative real‐time polymerase chain reaction (PCR) in 172 stable HTX patients. Sixty‐seven patients (39.0% of total) had a positive EBV PCR at initial examination [median 4.9 (range 1.1–16.9) years post‐HTX]. In follow‐up testing of 67 positive patients 6 months later, 36 patients continued to have a positive EBV PCR. Overall incidence of EBV DNA was significantly associated with calcineurin inihibitors, azathioprine medication, and with the absence of mycophenolate mofetil (MMF) treatment. In patients with positive EBV DNA levels at initial examination and negative levels at retesting, cyclosporine A levels were found to be significantly higher at initial examination (148.4 ± 70.2 vs. 119.6 ± 53.5 ng/ml, P < 0.05). Three patients (1.7%, 3/172) were diagnosed with PTLD during the course of the study (mean follow up 4.0 years). EBV DNA viral load determination does not appear to be useful for risk prediction or early diagnosis of PTLD in adults after HTX, but an association of EBV DNA load with qualitative and quantitative immunosuppression is demonstrated.

Proton Pump Inhibitor Co-medication Reduces Active Drug Exposure in Heart Transplant Recipients Receiving Mycophenolate Mofetil

BACKGROUND Proton pump inhibitors (PPIs) are often prescribed for gastrointestinal discomfort after heart transplantation. This study investigated the impact of PPI use on mycophenolic acid (MPA) pharmacokinetics in heart transplant recipients receiving mycophenolate mofetil (MMF) in combination with a calcineurin inhibitor (tacrolimus [TAC]/cyclosporine [CsA]) or mammalian target of rapamycin inhibitor (sirolimus/everolimus). METHODS Abbreviated MPA areas under the curve (AUCs; 0, 30, and 120 minutes after morning intake) were obtained in 19 patients on a PPI (initial examination) and 1 month after PPI discontinuation (follow-up). Mean patient age was 58.2 ± 8.8 years, and mean time after transplantation was 2.3 ± 4.0 years (range, 0.2-13.0 years). RESULTS At initial examination mean daily MMF dose was 2.2 ± 0.8 g. MMF dose was kept unchanged for the duration of study (P = ns). Mean predose (C0) MPA serum concentrations were insignificantly lower with PPI comedication (2.5 ± 2.2 mg/L vs 2.8 ± 1.7 mg/L; P = .15). Dose-adjusted abbreviated MPA AUCs (adjusted to morning dose) were significantly lower during PPI therapy (45.2 ± 20.3 vs 65.2 ± 38.8 mg·h/L·g [MMF]; P = .02). CONCLUSIONS Patients with PPI comedication during MMF therapy show significantly lower exposure to mycophenolic acid determined by dose-adjusted abbreviated MPA AUCs. Although the clinical relevance of this pharmacokinetic interaction was not determined in this study, MPA drug monitoring by limited sampling strategies might be helpful during changes in antacid comedication in patients on MMF.

Negative pretransplant serostatus for Toxoplasma gondii is associated with impaired survival after heart transplantation.

Chronic Toxoplasma gondii infection is known to trigger potentially adverse immunoregulatory changes, but limited data exist on long‐term implications for heart transplant (HTX) recipients. We evaluated the risk of all cause mortality regarding T. gondii serostatus prior to HTX. Pre‐HTX T. gondii serostatus was obtained in 344 recipients and 294 donors. Mean age was 52.1 ± 10.2 years and mean follow‐up time after HTX was 5.7 (±5.5, median 3.5) years. All seronegative patients received prophylaxis with pyrimethamine/sulfomethoxazole or cotrimoxazol for 6 months after transplantation. Multivariate survival analysis adjusted for diabetes mellitus, pre‐HTX renal function, recipient age, type of primary immunosuppression (i.e. HTX before 2001), cytomegalovirus (CMV) high‐risk status, ischemic time, and number of treated rejection episodes was performed. Overall, 190 recipients (55.2% of total) were seronegative and 154 (44.8% of total) were seropositive for T. gondii prior to HTX. One hundred and fifty‐two recipients died during follow‐up (44.2% of total). Negative recipient Toxoplasma serostatus was associated with a significantly higher risk of all‐cause mortality (P = 0.0213). Recipient T. gondii serostatus did not influence the number of cellular or humoral rejection episodes. Analyses of specific causes of death showed a trend toward a higher number of infection‐related deaths in the seronegative subgroup (P = 0.13). No statistically significant effects of T. gondii donor/recipient seropairing, or seroconversion were observed. Negative preoperative serostatus for T. gondii in HTX recipients appears to be an independent risk factor associated with increased all‐cause mortality. The cause of impaired survival in Toxoplasma seronegative recipients is currently unclear; possible explanations include an alteration of immune‐reactivity/‐regulation or adverse effects of prophylactic medication.

Increased Incidence of Acute Graft Rejection on Calcineurin Inhibitor–Free Immunosuppression After Heart Transplantation

BACKGROUND Calcineurin inhibitor (CNI)-free immunosuppression is used increasingly after heart transplantation to avoid CNI toxicity, but in the absence of a randomized trial, concerns remain over an increased rejection risk. METHODS We studied the incidence of graft rejection episodes among all cardiac graft recipients, beginning with the first introduction of CNI-free protocols. We compared events during CNI-free and CNI-containing immunosuppression among 231 transplant recipients of overall mean age 55.2 ± 11.8 years, from a mean 5.2 ± 5.4 years after transplantation through a mean follow-up of 3.1 ± 1.4 years. We considered as acute rejection episodes requiring treatment those of International Society for Heart and Lung Transplantation. RESULTS During the total follow-up of 685 patient years (CNI-containing, 563; CNI-free, 122), we performed 1,374 biopsies which diagnosed 78 rejection episodes. More biopsies were performed in CNI-free patients: biopsies/patient-month of CNI-containing, 0.13 versus CNI-free, 0.22 (P < .05). The incidence of rejection episodes per patient-month was significantly higher on CNI-free compared with CNI therapy, among patients switched both early and later after heart transplantation, namely, within 1 year, 0.119 versus 0.035 (P = .02); beyond 1 year, 0.011 versus 0.004 (P = .007); beyond 2 years, 0.007 versus 0.003 (P = .04); and beyond 5 years: 0.00578 versus 0.00173 (P = .04). CONCLUSIONS Rejection incidence during CNI-free immunosuppression protocols after heart transplantation was significantly increased in both early and later postoperative periods. Given the potentially long delay to rejection occurrence, patients should be monitored closely for several months after a switch to CNI-free immunosuppressive protocols.