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Rat lung allograft rejection is mediated by collagen type V (col(V)) specific T-helper-cell 17 (Th17) cells. Adoptive transfer of these cells is sufficient to induce rejection pathology in isografts, whereas tolerance to col(V) suppresses allograft rejection. Therefore, we tested whether regulatory T cells from tolerant rats could suppress the Th17-mediated rejection in the syngeneic model of lung transplantation.Rats were subjected to syngeneic left lung transplantation, and acute rejection was induced by adoptive transfer of lymph node cells from col(V)-immunized rats. Tolerance was induced by intravenous injection of col(V), and spleen lymphocytes were used for adoptive transfer. CD4+ T cells were depleted using magnetic beads. Lung isografts were analyzed using micro-positron emission tomography imaging and histochemistry. The transvivo delayed type hypersensitivity assay was used to analyze the Th17 response.Adoptive cotransfer of col(V)-specific effector cells with cells from col(V)-tolerized rats suppressed severe vasculitis and bronchiolitis with parenchymal inflammation, and the expression of interleukin (IL)-17 transcripts in mediastinal lymph nodes induced by effector cells alone. Analysis by transvivo delayed type hypersensitivity showed that the reactivity to col(V) was dependent on the presence of tumor necrosis factor-alpha and IL-17 but not interferon-gamma. Depletion of CD4+ T cells from the suppressor cell population abrogated the col(V)-specific protection.Th17-mediated acute rejection after lung transplantation is ameliorated by CD4+ col(V)-specific regulatory T cells. The mechanism for this Th17 suppression is consistent with tolerance induction to col(V). The goal of transplantation treatment, therefore, should target Th17 development and not suppression of T-cell activation by suppressing IL-2.

Background. The role of bone marrow-derived “passenger” leukocytes in the outcome of solid organ transplantation remains controversial. This study tested the relationship between high levels of donorderived leukocytes within the transplanted organ and clinical outcome after lung transplantation. Methods. Sequential bronchoalveolar lavage samples were obtained from human lung allograft recipients. Leukocytes of donor origin in the bronchoalveolar lavage fluid were detected using two-color immunofluorescence, and the results were correlated with multiple clinical parameters. Results. Mean donor leukocyte levels for the first 200 days after transplantation were higher in patients with a good transplantation outcome compared with those patients who lost their grafts due to acute rejection (AR) or developed bronchiolitis obliterans syndrome. The presence of low numbers of donor-derived leukocytes for the first 200 days after transplantation was found to be a significant risk factor for graft loss due to either acute or chronic rejection (P50.032). Nearly all patients (85%) experienced AR episodes. However, the time to onset of severe AR episodes was significantly longer (P50.049), and the incidence of these episodes reduced, in patients who maintained high numbers of donor-derived leukocytes for the first 200 days after transplantation. Conclusions. The presence of high numbers of donor-derived leukocytes, particularly macrophages, in the transplanted lung in the first 200 days after transplantation was associated with stable graft function. Donor-derived leukocytes were reduced or absent in patients with a poor transplantation outcome. These findings rule out a negative influence of persisting donor leukocytes and are consistent with the emerging two-way models of transplant tolerance.

Macromolecules are present in lung preservation solutions to limit liquid filtration out of the pulmonary circulation and minimize pulmonary edema. We tested the effectiveness of these molecules by measuring interstitial edema in rat lungs perfused with macromolecular solutions (University of Wisconsin [UW] solution and Euro-Collins solution supplemented with modified pentastarch [pentafraction, PEN]) or with solutions that lacked macromolecules (UW solution with PEN and Euro-Collins solution.) The lungs were inflated with air and perfused with one of the test solutions, then rapidly frozen and prepared for histological analysis. From tissue sections, we measured cross-sectional areas of pulmonary arteries and veins, and also measured cross-sectional areas of the interstitial spaces surrounding arteries and veins. We then calculated the interstitium-to-vessel cross-sectional area ratio. In lungs perfused with macromolecular solutions these ratios were 0.09+/-0.15 and 0.53+/-0.56 (mean +/- SD) for UW solution and Euro-Collins solutions solution with PEN, respectively (P

The role of bone marrow-derived "passenger" leukocytes in the outcome of solid organ transplantation remains controversial. This study tested the relationship between high levels of donor-derived leukocytes within the transplanted organ and clinical outcome after lung transplantation.Sequential bronchoalveolar lavage samples were obtained from human lung allograft recipients. Leukocytes of donor origin in the bronchoalveolar lavage fluid were detected using two-color immunofluorescence, and the results were correlated with multiple clinical parameters.Mean donor leukocyte levels for the first 200 days after transplantation were higher in patients with a good transplantation outcome compared with those patients who lost their grafts due to acute rejection (AR) or developed bronchiolitis obliterans syndrome. The presence of low numbers of donor-derived leukocytes for the first 200 days after transplantation was found to be a significant risk factor for graft loss due to either acute or chronic rejection (P=0.032). Nearly all patients (85%) experienced AR episodes. However, the time to onset of severe AR episodes was significantly longer (P=0.049), and the incidence of these episodes reduced, in patients who maintained high numbers of donor-derived leukocytes for the first 200 days after transplantation.The presence of high numbers of donor-derived leukocytes, particularly macrophages, in the transplanted lung in the first 200 days after transplantation was associated with stable graft function. Donor-derived leukocytes were reduced or absent in patients with a poor transplantation outcome. These findings rule out a negative influence of persisting donor leukocytes and are consistent with the emerging two-way models of transplant tolerance.

Macromolecules are present in lung preservation solutions to limit liquid filtration out of the pulmonary circulation and minimize pulmonary edema. We tested the effectiveness of these molecules by measuring interstitial edema in rat lungs perfused with macromolecular solutions (University of Wisconsin [UW] solution and Euro-Collins solution supplemented with modified pentastarch [pentafraction, PEN]) or with solutions that lacked macromolecules (UW solution with PEN and Euro-Collins solution.) The lungs were inflated with air and perfused with one of the test solutions, then rapidly frozen and prepared for histological analysis. From tissue sections, we measured cross-sectional areas of pulmonary arteries and veins, and also measured cross-sectional areas of the interstitial spaces surrounding arteries and veins. We then calculated the interstitium-to-vessel cross-sectional area ratio. In lungs perfused with macromolecular solutions these ratios were 0.09+/-0.15 and 0.53+/-0.56 (mean +/- SD) for UW solution and Euro-Collins solutions solution with PEN, respectively (P/=0.05). In lungs perfused with solutions that lacked macromolecules, area ratios were 0.48+/-0.88 and 1.95+/-1.82 for UW solution without PEN and Euro-Collins solution, respectively (P/=0.05). Solutions containing PEN caused less interstitial expansion than their counterparts that lacked it, but UW solution without PEN caused interstitial expansion equal to that of Euro-Collins solution with PEN. We conclude that macromolecules limit edema formation, but other constituents of UW solution limit edema formation also.

A new flushout solution for preservation of the pancreas was tested in the dog model of segmental pancreas autotransplantation. The solution osmolality was 320 mOsm/L, K+ = 120 mM, Na+ = 30 mM, and it contained the anion, lactobionate, and raffinose as impermeants to the cell. Preservation times studied were 48 and 72 hr. The pancreas was flushed out with about 250 ml of the new solution and stored at 0 degrees C. Dogs were monitored postoperatively for blood glucose and intravenous glucose tolerance (IVGTT). Results were compared with control (no preservation) segmental pancreas autotransplants. Dogs receiving pancreases stored for 48 or 72 hr were normoglycemic on day one and remained normoglycemic for at least 28 days, or until time of sacrifice. Two of four dogs with pancreases stored for 48 hr were sacrificed on day 14 with normal IVGTT for histology. The remaining two dogs had normal pancreatic function for 28 days. Two of eight dogs receiving pancreas grafts after 72-hr cold storage died of causes unrelated to the pancreas graft, which was still functioning at the time of death. Six dogs remained normoglycemic and had a normal IVGTT at least for 28 days. This study demonstrates the feasibility of preserving the pancreas for three days for transplantation.

Human fetal pancreas (HFP) represents an ideal tissue source for transplantation into diabetic patients. Transplantation of HFP lacks many of the technical problems associated with whole organ transplantation and HFP is readily available. In order to proceed with clinical HFP transplantation it must be demonstrated that HFP can reverse experimentally induced diabetes, that HFP can respond to glucose challenge in a manner similar to adult tissue, and that the immunogenicity of HFP can be reduced. We transplanted HFP (13–17 weeks gestational age) beneath the kidney capsule of streptozotocin-induced diabetic BALB/c nu/nu mice. Within 6 to 8 weeks following transplantation, 6 out of 7 (88%) animals became normoglycemic. Oral glucose tolerance tests were performed to determine in vivo graft function. Results in cured animals 'were identical to those of normal BALB/c nu/nu mice. In vitro insulin response to glucose challenge demonstrated that grafted HFP was capable of insulin secretion in the presence of high glucose while fresh fetal tissue was not. Human passenger leukocytes, identified immunohistologically at various times after transplantation with monoclonal antibodies to HLA-DR and Leu 10, were greatly reduced by 32 weeks posttransplant. Our data demonstrate that HFP will differentiate and mature in the diabetic nude mouse and that human passenger leukocyte content can be reduced. These findings suggest that HFP is functionally suitable for transplantation into diabetic patients.