Severe Vascular Rejection Research Articles

Synergism of imatinib, vatalanib and everolimus in the prevention of chronic lung allograft rejection after lung transplantation (LTx) in rats.

Chronic lung allograft dysfunction (CLAD) still remains a major drawback in the outcome following lung transplantation (LTx). New therapeutic strategies are warranted. Growth factors and their receptors like platelet-derived growth factor-receptor (PDGFR) and vascular endothelial growth factor-receptor (VEGFR), may play a crucial role in the development of CLAD, especially bronchiolitis obliterans (BO) and vasculopathy. In this study, we used an orthotopic left lung transplantation model from Fischer (F344) to Wystar Kyoto (WKY) rats to investigate the effect of the receptor tyrosine kinase inhibitor (RTKI) vatalanib alone, the dual combination of vatalanib and imatinib and a triple therapy consisting of vatalanib, imatinib and the mammalian target of rapamycin inhibitor (mTORI) everolimus on the development of CLAD after LTx in rats. With this trial we demonstrated that monotherapy with vatalanib attenuated mild and severe chronic vascular rejection, whereas dual therapy (vatalanib and imatinib) after LTx also showed a significant reduction of chronic bronchiolar rejection and interstitial fibrosis. By adding everolimus, the effect of vatalanib and imatinib could additionally be increased. In conclusion, the combination of mTORI and RTKIs might be a possible strategy in the prevention of CLAD and BO.

The influence of non-HLA antibodies directed against angiotensin II type 1 receptor (AT1R) on early renal transplant outcomes.

Non-HLA antibodies (Abs) targeting vascular receptors are thought to have an impact on renal transplant injury. Anti-angiotensin II type 1-receptor-activating antibodies (anti-AT1R) have been mentioned to stimulate a severe vascular rejection, but the pretransplant screening has not been introduced yet. The aim of our study was to assess the incidence and importance of anti-AT1R antibodies and their influence on renal transplant in the 1st year of observation. We prospectively evaluated the presence of anti-AT1R antibodies in 117 consecutive renal transplant recipients in pre- and post-transplant screening. Anti-AT1R antibodies were observed in 27/117 (23%) of the analyzed recipients already before transplantation. The function of renal transplant was considerably worse in anti-AT1R(+) group. The patients with anti-AT1R Abs >9U/ml lost their graft more often. Biopsy-proven AR was described in 4/27 (15%) pts in the anti-AT1R(+) group and 13/90 (14.4%) in the anti-AT1R(-) group, but more severe cases of Banff IIB or antibody-mediated rejection (AMR) were more often observed in anti-AT1R (+) 4/27 (15%) vs. 1/90 (1.1%) in anti-AT1R(+) (P=0.009). Patients with anti-AT1R Abs level >9U/ml run a higher risk of graft failure independently of classical immunological risk factors. The recipients with anti-AT1R Abs developed more severe acute rejections described as IIB or AMR in Banff classification. More recipients among the anti-AT1R-positive ones lost the graft. Our study suggests monitoring of anti-AT1R Abs before renal transplantation for assessment of immunologic risk profiles and the identification of patients highly susceptible to immunologic events, graft failure, and graft loss.

Trasplante renal en bloque de donantes pediátricos

Objetivo: Determinar la aceptación de ambos riñones de donantes pediátricos para utilizarlos como trasplante renal en bloque. Material y Métodos: La edad de los seis donantes varió entre 14 meses y 10 años. La causa de muerte fue el traumatismo encefalocraneano. La edad de los seis receptores osciló entre 15 y 48 años con peso menor de 50 kg. Ambos riñones fueron removidos en bloque. La técnica operatoria de los trasplantes consistió en la anastomosis término lateral del segmento aórtico y vena cava inferior del donante a los vasos ilíacos del receptor; ambos uréteres fueron anastomosados por separado a la vejiga. El implante fue localizado en una de las fosas ilíacas. Resultados: Los injertos en bloque funcionaron inmediatamente. Cuatro de los seis receptores cursaron con función renal adecuada a cuatro años promedio de seguimiento. Uno de los injertos en bloque se perdió por rechazo vascular severo y otro por indisciplina a la medicación inmunosupresora. Las series ecográficas de los riñones revelaron incremento de tamaño hasta en 55% de su dimensión original al tercer mes del trasplante. Conclusión: Se recomienda que los riñones procedentes de donantes menores de tres años de edad sean utilizados como trasplante en bloque y riñones de donantes mayores de tres años como trasplante renal simple. Se demuestra que es posible trasplantar exitosamente riñones en bloque de niños muy pequeños en receptores mayores, según experiencia inédita en nuestro medio.

Receptor-activating autoantibodies and disease: preeclampsia and beyond

The research reviewed in this article provides examples of autoantibody-mediated receptor activation that likely contributes to disease. The classic example is Graves’ hyperthyroidism, in which autoantibodies activate the thyroid-stimulating hormone receptor resulting in overproduction of thyroid hormones. Other compelling examples come from the cardiovascular literature and include agonistic autoantibodies targeting the cardiac β1-adrenergic receptor, which are associated with dilated cardiomyopathy. Autoantibodies capable of activating α1-adrenergic receptors are associated with refractory hypertension and cardiomyopathy. A prominent example is preeclampsia, a hypertensive disease of pregnancy, characterized by the presence of autoantibodies that activate the major angiotensin receptor, AT1. AT1 receptor-activating autoantibodies are also observed in kidney transplant recipients suffering from severe vascular rejection and malignant hypertension. AT1 receptor-activating autoantibodies and antibodies that activate the endothelin-1 receptor, ETA, are prevalent in individuals diagnosed with systemic sclerosis. Thus, the presence of agonistic autoantibodies directed to G protein-coupled receptors has been observed in numerous cardiovascular disease states. Rapidly emerging evidence indicates that receptor-activating autoantibodies contribute to disease, and that efforts to detect and remove these pathogenic autoantibodies or block their actions will provide promising therapeutic possibilities.

Cholesterol embolization and severe vascular rejection in a renal allograft recipient

Cholesterol embolization (CE) is a well-known cause of renal dysfunction, often leading to irreversible renal failure most often in elderly patients. However, because of its unspecific and subclinical appearance, CE is often misdiagnosed. As donors and recipients of increasing age or with prominent atherosclerotic disease are accepted for transplantation, CE in renal allografts may become more prevalent. Here, we report a case of a 31-year-old second renal allograft recipient with CE as a cause of early graft failure, followed by severe vascular rejection, eventually requiring nephrectomy.

An ABO‐incompatible renal transplant patient who developed severe antibody‐mediated vascular rejection 36 days after transplantation

Abstract: A 44‐yr‐old man had an ABO‐incompatible renal transplantation from his 41‐yr‐old wife. He was diagnosed with IgA nephropathy at the age of 31 and began hemodialysis to treat chronic renal failure at the age of 39. Preoperative flow panel reactive antibody was negative. An episode biopsy on post‐operative day (POD) 18 showed mild infiltrative vasculopathy (v1, g2, ptc1, TMA, PTC+). The serum creatinine (sCr) was 2.26 mg/dL. Anti‐A antibody was x32. Double filtration plasmapheresis and plasma exchange were performed. A second episode biopsy was performed on POD 36. The Cr was 3.73 mg/dL. Anti‐A antibody was x32. Histologically, antibody‐mediated vascular rejection with severe fibrinoid necrosis in the lobular arteries was detected (v3, g2, ptc2, TMA, PTC+). Steroid pulse therapy was performed, and OKT‐3 was administered for 10 d. The anti‐A antibody titer was x128 on POD 47. A biopsy specimen obtained on POD 55 showed severe vascular rejection with stenosis of the vascular lumen and fibrinoid necrosis (v3, cv2, g1, cg2, ptc1, TMA, PTC+). The sCr was 7.09 mg/dL. Despite double‐filtration plasmapheresis, the patient was reintroduced to hemodialysis. Here, we report a case showing the typical histological features of antibody‐mediated vascular rejection.

Renal Retransplantation: A Retrospective Monocentric Study

Approximately 10% to 20% of all annual renal transplantations are retransplantations and up to 20% of patients on waiting lists need a repeat kidney because of previous graft failure. The immunological risk is much greater among retransplanted patients than first-time kidney recipients. It is likely that retransplantation will become even more prevalent in the future. However, clinical studies or retrospective data are rare in this patient population. We retrospectively investigated 50 recipients after second or third renal transplantations in our center since 2001. Immunosuppression was performed with corticosteroids, mycophenolate mofetil (MMF), tacrolimus, and induction therapy with either thymoglobulin (2.5 mg/kg body weight; n = 27) or 20 mg basiliximab on days 0 and 4 (n = 22) after renal transplantation; 1 patient was treated with antithymoglobulin Fresenius after combined liver–kidney transplantation. Acute rejection occurred in 12 recipients (44.4%) after thymoglobulin and in 7 recipients (31.8%) after basiliximab induction therapy ( P < .05). In 4 (14.8%) thymoglobulin- and 5 (22.7%) basiliximab-treated recipients, vascular rejections were observed ( P = NS). Patients with basiliximab treatment showed improved renal function at 1 year after transplantation: serum creatinine 134.3 μmol/L versus 199.6 μmol/L in the thymoglobulin group ( P < .05). Over the observation period the renal function remained stable or improved in both groups if rejection treatment was successful. However, allograft failure was higher in the basiliximab-treated group, namely, 18.1% versus 14.8% in thymoglobulin-treated patients, but the difference did not reach statistical significance. In 3 (11.1%) thymoglobulin- and 4 (18.2%) basiliximab-treated patients cytomegalovirus (CMV) infections complicated the follow-up ( P = NS). In the follow-up period of 5 years, no malignant diseases were seen in either group. Three basiliximab-treated recipients died in the first year due to sepsis or cardiovascular complications. Two thymoglobulin-treated patients developed BK virus nephropathy in the follow-up period. In conclusion, we observed a high immunological risk and rejection risk among retransplanted kidney recipients in our center. Particularly, severe vascular rejections with a harmful long-term impact on allograft function were observed in this population. Induction treatment seems to be successful to reduce risk and achieve better results. Single-shot thymoglobulin may be preferable to reduce severe vascular rejection and prevent allograft failure than basiliximab with the same infection rate.

Maintenance of Airway Epithelium in Acutely Rejected Orthotopic Vascularized Mouse Lung Transplants

Lung transplantation remains the only therapeutic option for many patients suffering from end-stage pulmonary disease. Long-term success after lung transplantation is severely limited by the development of bronchiolitis obliterans. The murine heterotopic tracheal transplantation model has been widely used for studies investigating pathogenesis of obliterative airway disease and immunosuppressive strategies to prevent its development. Despite its utility, this model employs proximal airway that lacks airflow and is not vascularized. We have developed a novel model of orthotopic vascularized lung transplantation in the mouse, which leads to severe vascular rejection in allogeneic strain combinations. Here we characterize differences in the fate of airway epithelial cells in nonimmunosuppressed heterotopic tracheal and vascularized lung allograft models over 28 days. Up-regulation of growth factors that are thought to be critical for the development of airway fibrosis and interstitial collagen deposition were similar in both models. However, while loss of airway epithelial cells occurred in the tracheal model, airway epithelium remained intact and fully differentiated in lung allografts, despite profound vascular rejection. Moreover, we demonstrate expression of the anti-apoptotic protein Bcl-2 in airway epithelial cells of acutely rejected lung allografts. These findings suggest that in addition to alloimmune responses, other stimuli may be required for the destruction of airway epithelial cells. Thus, the model of vascularized mouse lung transplantation may provide a new and more physiologic experimental tool to study the interaction between immune and nonimmune mechanisms affecting airway pathology in lung allografts.

The role of angiotensin II type 1 receptor-activating antibodies in renal allograft vascular rejection

Acute rejection with vascular involvement remains a challenging problem in renal allotransplantation. Fibrinoid necrosis of the arteries with secondary thrombotic occlusions is C4d negative in 50% of cases and has the worst prognosis among all allograft vascular lesions. Nonhuman leukocyte antigen (HLA) non-complement-fixing antibodies reacting to artery-specific antigens have been speculated to be responsible for causing severe vascular injury. We recently reported the presence of agonistic antibodies against the angiotensin II type 1 receptor (AT(1)R-AA) in 16 recipients of renal allografts who had severe vascular rejection and malignant hypertension but who did not have anti-HLA antibodies. AT(1)R-AA stimulate AT(1)R and induce mediators of inflammation and thrombosis. Removal of AT(1)R-AA by plasmapheresis in combination with pharmacologic AT(1)R blockade leads to improved renal function and graft survival in AT(1)R-AA-positive patients. We have shown that the analysis of the subtle diagnostic and mechanistic differences may help to identify patients at particular risk and improve outcome of rejections with vascular pathology.

The transmission of donor‐derived malignant melanoma to a renal allograft recipient

The transmission to organ transplant recipients of donor origin malignancy in the allograft has been described. Here we report the transmission of malignant melanoma in a renal allograft transplanted from a multiorgan donor. The lung transplant recipient presented with an allograft lesion that was proven to be melanoma and of donor-origin based on human leukocyte antigen (HLA)-DR typing. One renal allograft recipient was undergoing his second deceased donor renal transplant, having lost his first graft from recurrent IgA nephropathy. He was unsensitized and immunosuppression consisted of tacrolimus, mycophenolate and prednisolone. He achieved stable graft function and there were no episodes of rejection. Four and a half months post-transplant a diagnosis of donor origin melanoma in the lung recipient was made and his immunosuppression was stopped. He presented with clinical rejection two wk later and a transplant nephrectomy was undertaken. Histology demonstrated vascular and cellular rejection and there was a 3-mm melanoma deposit with no evidence of tumour infiltrating lymphocytes. Three years post-transplant he remained clinically well with no evidence of melanoma and received his third deceased donor renal transplant. This was complicated by cellular rejection in the first week treated with methylprednisolone and vascular rejection at day 10 treated with anti-thymocyte globulin. Three months post-transplant he has achieved good allograft function and remains well with no evidence clinically or on imaging of metastatic melanoma. The other renal allograft recipient was receiving his first deceased donor transplant, having end-stage renal failure of uncertain aetiology. His immunosuppression was not stopped until melanoma was proven in the renal allograft pair six months post-transplant and he then presented with clinical rejection six wk later. Transplant nephrectomy was undertaken and histology did not demonstrate melanoma, but severe vascular and cellular rejection was evident. At three-yr post-transplant he remains disease free clinically and on imaging. At present, the cardiac allograft recipient has no evidence of transmitted melanoma. The highest risk of transmission of donor origin melanoma appears to be from donors who are older and have died from an intracerebral haemorrhage. It is likely these donors have metastatic melanoma and their intracerebral haemorrhage is not primary but has occurred in an unrecognized metastatic cerebral deposit. While the occurrence of donor-transmitted malignancy is not common, the outcome is often fatal.

Coronary artery vasospasm causing acute myocardial infarction in a heart transplant recipient

The etiology of cardiac allograft vasculopathy is not known, but may be preceded by both endothelial cell and smooth muscle dysfunction of the epicardial coronary arteries. We here report a case of acute, reversible coronary artery vasospasm which caused a myocardial infarction in a cardiac transplant recipient. The patient had a complex post-transplant course, including an episode of severe vascular rejection several months before this presentation. Interestingly, the event was captured in its early stages because the patient presented with chest pain: a rare event because of the denervation of the transplanted heart. Our ability to document the etiology of this patient’s myocardial infarction supports the concept that cardiac allograft vasculopathy is a progressive disease that, in its early stages, may include a reversible component of abnormal vasoreactivity.

Improved assessment of graft function by echocardiography in cynomolgus monkey recipients of hDAF-transgenic pig cardiac xenografts

Background The current practice of evaluating heterotopic heart xenografts by palpation allows only detection of severe graft dysfunction, which indicates terminal graft failure. Therefore, we evaluated whether echocardiography is a better method of detecting early graft dysfunction as a marker of rejection in abdominal pig heart xenografts in cynomolgus monkeys. Methods Six cynomolgus monkeys received heterotopic heart transplants from pig donors transgenic for human decay-accelerating factor (hDAF). Induction therapy consisted of either cyclophosphamide or rabbit anti-thymocyte globulin. Maintenance therapy consisted of cyclosporine or tacrolimus, steroids, and sodium mycophenolate or mycophenolate mofetil, GAS914 (αGal oligosaccharide containing glycoconjugate), and for some animals TP10 (soluble complement receptor type 1). Echocardiography was performed immediately after transplantation and 3 times a week after surgery. We scored contractility and measured left ventricular wall thickness. Impaired contractility or increased wall thickness were considered graft dysfunction and were treated with pulse steroids. Palpation score was recorded daily. We also obtained myocardial biopsy specimens. Results Palpation score remained at 4 out of 4 in all animals until 2 to 5 days before final graft failure, whereas echocardiography detected several episodes of impaired graft function, either decreased left ventricular contractility or increased left ventricular wall thickness before graft failure. Treatment with pulse steroids improved graft function only during early episodes of graft impairment. Final graft failure was steroid resistant and caused by severe vascular rejection. Conclusions Echocardiography is a better method of assessing graft dysfunction than is palpation. Therefore, echocardiography may detect early rejection episodes of heterotopic heart xenografts in non-human primates.

The role of microvascular injury on steroid and OKT3 response in renal allograft rejection.

The authors' aim is to understand the influence of human leukocyte antigen-DR positive microvascular (MV)-DR destruction on steroid and OKT3 response in acute rejection (AR). Twenty of 40 patients had steroid-resistant AR (group 1) and received OKT3 treatment, and the other 20 patients had AR that responded to steroid treatment (group 2). A renal biopsy specimen was obtained from each subject during the AR episode. The degree of MV-DR destruction and the peritubular capillary (PTC) leukocyte infiltration were recorded in each case, using three-tiered scales. The follow-up biopsy specimens of all cases were evaluated for the development of interstitial fibrosis (IF). Seventy-eight percent of the cases with severe MV destruction and 45% of those with moderate MV destruction did not show response to steroid therapy, whereas 74% of the cases with mild MV destruction responded to steroid therapy. Group 1 patients showed higher frequencies of vascular rejection (80%) and high-grade PTC leukocyte infiltration (85%) than the group 2 cases (P<0.01 for both). Seventy percent of the patients in group 1 responded to OKT3 therapy. The biopsy specimens from the six individuals who were resistant to OKT3 had shown severe MV destruction, vascular rejection, and high-grade PTC leukocyte infiltration. Severity of MV destruction in the initial AR diagnostic biopsy was positively correlated with development of diffuse IF and chronic allograft nephropathy in the follow-up biopsy specimens (P<0.001) Analysis of MV destruction may be helpful for diagnosing rejection and predicting graft prognosis. This type of assessment may be useful for determining the immune response and thus identifying the most appropriate treatment.

Endothelial cell chimerism after renal transplantation in a rat model.

Endothelial chimerism, that is, the replacement of damaged donor endothelium by recipient precursors, has been proposed to reduce the allogeneic stimulus and graft rejection. However, both its mechanism and consequence are poorly understood. In this study, we set up a rat model of renal transplantation to investigate the phenomenon of endothelial chimerism and the relationship among the factors involved in its induction, such as preischemic injury, severity of graft rejections, and the role of cyclosporine A toxicity. Female Lewis rats received renal transplants from male Brown Norway kidneys. Groups were divided according to ischemia or nonischemia of the donor kidney and cyclosporine treatment or nonimmunosuppression. To investigate the endothelial chimerism, an in situ hybridization by an X-chromosome-specific DNA probe was performed. The severity of allograft rejection was scored according to the Banff '97 classification. In grafts without preischemic injury or without cyclosporine A treatment, a low degree of endothelial chimerism was detected, although severe vascular rejection and tissue necrosis developed. More chimerism was found in recipients receiving an ischemic kidney followed by immunosuppressive treatment, although less severe rejection developed. In recipients receiving an ischemic kidney without cyclosporine A treatment, the highest degree of endothelial chimerism occurred. Endothelial chimerism demonstrated in rats after renal transplantation may be caused by endothelial damage induced by vascular rejection or ischemia. Ischemia had the strongest association with the induction of chimerism, which may function as a synergistic promoter. A low-dose cyclosporine A treatment was shown to inhibit endothelial replacement.

Ischemia-reperfusion injury in renal transplantation is independent of the immunologic background

Adhesion molecule expression is important to early transplant failure. However, whether or not adhesion molecule-facilitated inflammation is antigen-dependent is unknown. We tested this hypothesis. Rat renal grafts were four-hours cold-preserved in University of Wisconsin (UW) solution, transplanted to syngeneic or allogeneic recipients, and harvested after 2, 6, 12, 24, and 48 hours and after 1 week. The first allogeneic group receive no immunosuppression; two additional groups received either low (1.5 mg/kg) or standard (5 mg/kg) cyclosporine A (CsA). Renal function and morphology were determined; frozen sections were immunostained for P-selectin, L-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), platelet endothelial cell adhesion molecule-1 (PECAM-1), leukocyte function associated molecule-1 (LFA-1), very late antigen-4 (VLA-4), as well as for neutrophils and monocytes. Selectins increased rapidly at 2 hours and quickly decreased by 12 hours. While P-selectin was expressed on vasculature, L-selectin was found on inflammatory cells. Neutrophil influx and that of LFA-1-positive cells occurred early, peaked between 12 and 24 hours, and paralleled the maximal impairment in renal function. ICAM-1 and PECAM-1 showed similar kinetics and a diffuse distribution. VCAM-1 increased more slowly after 12 hours, peaked at 24 hours, and was localized predominantly on the endothelium of elastic vessels. Between 24 hours and 1 week, all grafts progressively developed dense VLA-4-positive monocytic infiltrates adjacent to vessels expressing VCAM-1. Functional, morphological, and immunohistochemical parameters did not differ between isografts and allografts at one week. However, by day 10, allografts showed severe vascular and cellular rejection, while injury in isografts resolved. Immunosuppression with CsA did not reverse the inflammation induced by ischemia-reperfusion injury. The early inflammation after ischemia-reperfusion injury is largely independent of the immunologic background. We suggest that initial injury prevention should receive the highest priority.

Intravenous synthetic alphaGal saccharides delay hyperacute rejection following pig-to-baboon heart transplantation.

Several oligosaccharides containing the terminal structure Gal(alpha)1-3Gal (alphaGal) and different side chains were tested in vitro for their ability to block natural anti(alpha)Gal antibodies. A di-and a trisaccharide (di(alpha)Gal and tri(alpha)Gal) were selected. A blood group B baboon, having IgG and IgM natural antipig titers of 1:256 and 1:1024 and a hemolytic titer (to pig red blood cells, RBCs) of 1:8, was chosen to measure pharmacokinetic parameters of the saccharides and to assess the extent of in vivo neutralization of the antibodies. Three grams each of the di(alpha)Gal and the tri(alpha)Gal dissolved in saline were administered by bolus intravenous (i.v.) injection. Blood samples were collected at various times and urine was collected at 8 and 24 h. Plasma and urine concentrations of the alphaGal saccharides were estimated by an ELISA specially developed for this study. A fast distribution phase followed by equilibrium and excretion phases were observed, indicating a T1/2 in the order of 1 h. Fifty-eight per cent of the saccharides were recovered in the urine within 24 h. Determination of antipig antibody binding by FACS analysis and of serum cytotoxicity titers for pig endothelial cells demonstrated that a 70% reduction in binding and cytotoxicity could be achieved with plasma saccharide levels of 300-400 microg/ml. Six months later, a pig heart was transplanted heterotopically into the baboon. A 3-g bolus of the saccharide mixture (1.5 g of each saccharide) was given i.v. before allowing blood reperfusion of the transplanted heart, followed by an i.v. infusion of 1 g/hr for 1 hr and 0.5 g/hr for the 3 succeeding hours. Blood concentrations of the saccharides, CH50, hematology and cytotoxicity for PK15 cells were estimated in blood samples taken at various times. Heart function was observed to be satisfactory for 8 h, but was found to have ceased at 18 h. Myocardial biopsies taken at 3 and 5 h showed congestion only, suggestive of minimal vascular rejection, but by 18 h demonstrated severe vascular rejection. In conclusion, alphaGal saccharide therapy given for a period of 4 h delayed, but did not totally prevent, the development of vascular rejection in the pig-to-baboon heart transplant model. alphaGal saccharide therapy may be one of several useful approaches for the prevention of hyperacute rejection in pig-to-primate organ transplantation.

Long-term survival of hamster-to-rat cardiac xenografts in the absence of a Th2 shift.

In hamster-to-rat cardiac xenografts, long-term survival (LTS) is obtained in 60% of recipients if vascular rejection is overcome by cobra venom factor and cyclosporine (CsA). It has been suggested that this accommodation state could be due to the Th2 response. We examined the infiltrate by using immunostaining and the accumulation of cytokine mRNA (interferon-gamma [IFN-gamma], interleukin [IL]-4, IL-10, IL-13, and transforming growth factor-betal [TGF-beta1]) by using competitive reverse transcriptase polymerase chain reaction, in hamster hearts grafted into LEW.1A rat. Hearts from untreated and treated (cobra venom factor and CsA) but rejecting recipients presented a rapid and severe vascular rejection. In contrast, hearts from long-surviving treated animals had subnormal cardiac muscle with a mild infiltrate, principally macrophages, which peaked on day 15. T lymphocytes were also maximal on day 15 (12% of the infiltrate). Rejected grafts from untreated recipients showed accumulation of IFN-gamma mRNA but low levels of IL-10, TGF-beta, and IL-13. In hearts rejected by treated recipients, IFN-gamma mRNA did not increase and TGF-beta mRNA was higher. In LTS, IL-10, TGF-beta, and IL-13 transcripts were up-regulated (P<0.001), while IFN-gamma mRNA decreased (P<0.001). In both groups, IL-4 expression remained at a nonsignificant level. The profile of cytokine mRNAs in LTS could result in part from CsA, known to up-regulate TGF-beta and to down-regulate IFN-gamma. Moreover, CsA does not inhibit IL-10 production by monocyte/macrophages, the major infiltrating cells (60%). Lastly, LTS is induced in the absence of IL-4, which suggests that the high IL-4 production could simply be correlated with LTS without being a condition for it.

Immunohistochemical characterization of inflammatory and proliferative events during chronic rejection in rat lung allografts.

Chronic rejection is assumed to be the principle cause of airway injury leading to obliterative bronchiolitis (OB) after lung transplantation (Tx). To better understand the contribution of chronic rejection in the development of OB in allografted lungs, we examined the histopathological changes and cytokine expression in inadequately immunosuppressed rat lung allografts. Three groups of rats were studied: group I, control nontransplanted Lewis (Lew) rats (n=5); group II, syngeneic Lew-to-Lew isografts (n=25); and group III, Brown Norway-to-Lew allografts (n=25). Groups II and III received two single doses of cyclosporine on postoperative days 2-3. Transplanted animals were killed (n=5) at monthly intervals from 2 months to 6 months after Tx. Resected lungs were stained with hematoxylin and eosin, Masson's trichrome, and Van Gieson's elastin, and immunostained with antisera to interleukin (IL)-1beta, IL-8, and basic fibroblast growth factor (bFGF). The intensity of immunostaining was graded from 0 to 4 (0=no staining, 4=strong staining). In groups I and II, normal airways and vessels were observed. Minimal intensity and distribution of immunostaining for all markers were detected in groups I and II. Group III allografts demonstrated acute grade II-III vascular rejection with mild bronchiolar injury and inflammation at 2 months after Tx. At 6 months after Tx, all allografts demonstrated severe and diffuse chronic vascular rejection. Late airway changes consistent with OB were detected in four of five allografts, however, these lesions were expressed infrequently. Immunohistochemical findings revealed moderate to strong expression for IL-8 and bFGF over the airway epithelium, acute and chronic inflammatory cells, and fibroblasts in allografts at 2 months after Tx. Despite focal development of OB at 6 months, intensity and distribution of immunostaining significantly decreased for all three cytokine markers. Inadequate immunosuppression of rat lung allografts leads primarily to chronic vascular rejection but fails to induce severe and diffuse development of OB. In this animal model, cytokines IL-1beta, IL-8, and bFGF are likely to play an important role in the early inflammatory phase but not during the late proliferative events of chronic rejection.

Single-center experience with renal transplantation in patients with Wegener's granulomatosis.

Between 1980 and 1995, 13 patients with end-stage renal disease due to Wegener's granulomatosis received 14 renal transplants (10 cadaveric, 4 living related). The mean follow-up in the 13 successfully transplanted patients was 50 months (4-107 months). One patient had primary nonfunction and received another graft 4 months later. Three episodes of acute rejection occurred in two patients, and one of these patients lost her graft due to severe vascular rejection 4 months after transplantation. Two patients died with well-functioning grafts (one of metastatic cancer and one of sepsis). One patient presented with perisinusitis and had a mild recurrence of Wegener's disease. None of the patients developed recurrent disease in the transplanted organ. At the last follow-up, the mean creatinine (+/-SD) in the 12 patients with functioning grafts was 1.6 +/- 0.6 mgdl. We conclude that renal transplantation is an excellent treatment for renal failure due to Wegener's granulomatosis. Recurrence of the disease is uncommon in patients under immunosuppression, but careful monitoring is extremely important.

Effect of Deoxyspergualin on Vascular Rejection in Canine Kidney Transplantation

Deoxyspergualin (DSG), an analogue of spergualin produced by Bacillus laterosporus, has a strong immunosuppressive effect in various transplantation models. In this study, we investigated the effect of DSG on vascular rejection in canine kidney transplantation.To enhance vascular rejection, donor-specific blood transfusion (DST) was carried out on days 28, 21 and 14 preceding kidney transplantation. After DST, the donor kidney was transplanted to the recipient iliac fossa. The recipient animals were divided into five groups: namely, Group 1 (n = 7), no treatment; Group 2 (n = 6), DST only; Group 3 (n = 5), DSG only (treated with DSG intravenously at 1.2 mg./kg./day for the first 3 days after transplantation, 1.0mg./kg./day for the following 3days and 0.8mg./kg./day for the following 8 days); Group 4 (n = 6), DST and DSG treatment (same protocol as Group 3); and Group 5 (n = 5), DST and cyclosporine (CsA) (treated with CsA orally at 10mg./kg./day for 14days after transplantation).In Group 2, DST treatment significantly reduced kidney graft survival time (8.6 ± 2.2 days) compared with Group 1 (14.1 ± 5.5 days). Despite DST, DSG treatment (Group 4) significantly prolonged graft survival time (29.5 ± 2.6 days), whereas treatment with CsA (Group 5) did not prolong survival time (14.1 ± 5.5 days) (Group 4 versus 5, p < 0.01).The onset of rejection was significantly delayed in Group 4 (22.1 ± 2.7 days) compared with Groups 2 (5.7 ± 2.4 days) and 5 (13.0 ± 5.7 days) (p < 0.01). In contrast, the interval between rejection onset and animal death was significantly reduced in Groups 2 (3.0 ± 0.6 days) and 5 (2.4 ± 1.0 days) compared with Group 4 (7.3 ± 1.7 days) (p < 0.01). These findings suggest that DSG successfully prevented humoral-type (accelerated acute-type) rejections.Histologically, nonDST groups (Groups 1 and 3) showed minimum vascular rejection. In contrast, all recipients in Group 2 showed severe vascular rejection, as did 80% of CsA treated-animals (Group 5). Despite DST, however, 84% of DSG treated-animals (Group 4) showed minimal or mild vascular rejection and only 17% had severe rejection (Group 4 versus 5, p < 0.04).These data suggest that both clinically and histologically, DSG has more potent immunosuppressive effects against humoral and vascular rejection than CsA.