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Purpose Warm perfusion of donor lungs for transplantation (Tx) using Organ Care System® (OCS) may provide superior preservation compared to standard cold preservation (SOC). Release and composition of donor-derived soluble immune mediators (IM), triggering allorecognition and inflammation after Tx, might be differentially affected. We analyzed 55 soluble IM in the respective preservation solutions (PS), as well as in peripheral blood (PB) of the recipient. Methods and Materials IM were quantified at protein level (pg/ml) by Luminex-based multiplex-technology in PS at the end of cold storage (SOC, n=11) or warm preservation in OCS (n=13), either based on low potassium dextrane solution. Differences were assessed using Mann-Whitney-U and ROC / AUC statistics. Results Unexpectedly huge differences were found between concentrations in PS, extrapolating to several μg for large volume of PS (1.0– 1.5l). We focus on those 20 factors displaying highest statistical differences with higher release in OCS: IL-6 p Conclusions Donor-derived IM remained low in SOC, whereas OCS potentially depleted them from the organ with accumulation in PS. This ‘dialysis’ effect may indicate anti-inflammatory properties. Further studies on clinical outcomes of patients transplanted with OCS vs. SOC preserved lungs are warranted.

Purpose Regulatory T cells (Treg) play important roles in the induction and maintenance of immunological tolerance to self and non-self antigens. They have the potential to regulate alloantigens and thus may counteract the development of acute and chronic rejection (i.e. BOS) in lung transplant recipients. BOS affects over 60% of lung transplant recipients within 5 years after transplantation. Here, we present a cohort of 89 patients, in which we analyzed Tregs in peripheral blood prospectively during the first 2 years after lung transplantation and correlate with the onset of BOS. Methods and Materials In consecutive routine lung transplant recipients, the number of circulating Treg was detected by flow cytometry before transplantation and 3 weeks, 3 6,12, 18 and 24 months after transplantation. Treg were defined as CD4+CD25high T cells and were further analyzed for relevant surface as well as intracellular markers such as, amongst others, CTLA4, CD127, FoxP3 and IL-2. Additionally, lung function results at that time points were analyzed. We divided the cohort into two groups based on the development of BOS stage 0-p versus BOS stage 1 or higher. Results A total of 89 consecutive patients were included into the study. 25 patients developed a BOS stage 1 or higher 2 years after transplant. 64 patients showed a good clinical course with stable lung function. A statistically significant positive correlation could be detected between the frequencies of CD4+CD25highCD127low T cells, CD4+CD25highCTLA-4+ T cells, CD4+CD25highFoxP3+ T cells and CD4+CD25highIL-2 + T cells and the absence of BOS within the first 2 years after lung transplantation (p 0.05). Conclusions Higher frequencies of CD4+CD25highCD127low T cells, CD4+CD25highCTLA-4+ T cells, CD4+CD25highFoxP3+ T cells and CD4+CD25highIL-2 + T cells early after transplantation are associated with protection against development of BOS during the initial 2 years after lung transplantation.

Purpose In animal models, both naive and alloantigen-primed Treg inhibit rejection. In clinical recipients of transplants, however, not much is known with regard to the actual function of those Treg that can be found in vivo. Here, we studied the functional importance of both naive and alloantigen-primed T cell responses in a humanized mouse model, utilizing transplant arteriosclerosis as the experimental readout. Methods and Materials The pericardiophrenic artery was procured from leftover tissue of lung grafts transplanted within our clinical program and was implanted into the abdominal aorta of NRG mice. Group A received no human leukocyte and served as negative controls. Group B received 5x106 allogeneic human PBMC from the respective lung recipient harvested at the time of transplant and group C received the same naive allogeneic PBMC, depleted of CD4+CD25+ putative Treg. Group D received naive allogeneic PBMC enriched of these CD4+CD25+ cells. Group E received PBMC harvested 21 days after transplantation, containing the alloantigen-primed T cells. Human leukocyte engraftment was monitored and transplant arteriosclerosis was histologically assessed 28 days later. Results The control group A showed mild thickening of the intima. In group B intimal thickening resulting in severe obliteration of the vessel lumen was evident. In group C obliteration of the lumen was even more severe. By contrast, in group D intimal thickening was less severe. In group E, reconstituted with alloantigen-primed total PBMC, only very mild transplant arteriosclerosis developed, comparable to group D enriched of naive Treg. Conclusions We show the importance of T cell regulation for controlling alloresponses in vivo. The finding of reduced transplant arteriosclerosis elicited by alloantigen-primed PBMC is intriguing and may indicate enhanced T cell regulation in these clinical transplant recipients. Ongoing studies aim at correlating clinical transplant outcomes to T cell function assessed using humanized mouse.

Purpose Combined heart–lung transplantation (HLTx) is a therapeutic option for both adult and pediatric patients since the early 1980s. The leading indications for HLTx are congenital heart disease with Eisenmenger’s syndrome and, historically idiopathic pulmonary arterial hypertension. HLTx is plagued by frequent postoperative acute renal failure (ARF) requiring hemodialysis (up to 80%), by far not always explained by perioperative hemodynamic instability and other well-known risk factors. Here, we hypothesized that high levels of creatine phosphokinase (CPK) or myoglobine would predict acute renal failure after combined heart lung transplantation. Methods and Materials In this study, we present a cohort of 75 patients, who received combined heart and lung transplantation between 2002 and 2012 at Hanover Medical School. In this cohort we defined 2 groups according to the development of ARF requiring hemodialysis after transplant. In both groups CK, CKMB and myoglobin were measured preoperative and at the time of 6h, 12h, POD 1, POD 2, POD 3, POD 4, POD 5, POD 6 and once weekly up to 8 weeks after transplantation. We also assessed at which time after transplant the patients received the first course of hemodialysis. Results Of a total of 75 patients included into this study, 42 developed ARF after transplant und needed hemodialysis. The first course of hemodialysis was necessary on POD 2 (mean). 33 patients showed sufficient renal function. We detected a statistically significant positive correlation between CPK and myglobine levels in blood during the first 48 hours preceeding initiation of hemodialsis and the development of ARF (p Conclusions High CPK and myglobine levels in peripheral blood predict (and might even cause) the development of acute kidney injury immediately after combined heart lung transplantation.

Purpose Primary Graft Dysfunction(PGD)in Lung Transplantation (LTX) occurs in 8-20% of all LTX and usually is combined with increased morbidity and mortality of 30-40%. A deficit of C1-INH presents a clinical picture of severe capillary leakage. Therefore, we hypothesized that application of C1-INH in LTX recipients that show first signs of severe ischemia-reperfusion injury attenuates PGD. Methods and Materials All LTX recipients that showed low oxygenation indices ( Results A total of 296 LTX were performed between May 2010 and September 2012 at our centre. Out of this, 24 patients (8.11%) developed a low oxygenation index at the end of surgery (mean 85.46 mmHg) and were treated with C1-INH. The PGD Score (ISHLT) was significantly higher in the C1-INH treated group directly postoperatively, 24 hours, 48 hours and 72 hours postoperatively (T0 2.42±0.21vs. 0,74±0.06, p Conclusions PGD is a serious complication after LTX, but treatment with C1-INH led to acceptable morbidity and mortality. Although survival in the C1-INH treated patients was lower than in the remaining collective, it was effectively as good or better as what is internationally regarded as reasonable outcome after LTX in general (>83% one-year-survival).