| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
a Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
b Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
c Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
d Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri
Accepted for publication March 28, 2008.
* Address correspondence to Dr Mohanakumar, Washington University School of Medicine, Department of Surgery, Box 8109-3328 CSRB, 660 S Euclid Ave, St. Louis, MO 63110 (Email: kumart{at}wustl.edu).
Presented at the Forty-fourth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28–30, 2008. Winner of the J. Maxwell Chamberlain Memorial Award for General Thoracic Surgery.
 |
Abstract |
|---|
 Top Abstract IntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
Methods: Primary graft dysfunction and broncholitis obliterans syndrome were diagnosed according to the established International Society for Heart and Lung Transplantation criteria. Anti–human leukocyte antigen (HLA) alloantibodies were analyzed using Flow-PRA. Donor HLA class II–specific T cells were analyzed using interferon (IFN)-
ELISPOT. Serum levels of 25 cytokines and chemokines were measured using LUMINEX.
Results: Of the 127 subjects, 29 (22.8%) had no PGD (grade 0), 42 (33.2%) had PGD-1, 36 (28.3%) had PGD-2, and 20 (15.7%) had PGD-3. Patients with PGD grades 1 to 3 (PGD1-3) had elevated proinflammatory mediators MCP-1, IP-10, interleukin (IL)-1β, IL-2, IFN-, and IL-12 in the sera during the early posttransplant period compared with patients with PGD grade 0 (PGD0). On serial analysis, PGD1-3 patients revealed increased development of de novo anti-HLA-II (5 years: 52.2% versus PGD0 13.5%, p = 0.008). However, no difference was found in anti-HLA-I alloantibody development (PGD1-3 patients 48% versus PGD0 39.6%, p = 0.6). Furthermore, PGD1-3 patients had increased frequency of donor HLA class II–specific CD4+ T cells [(91.4 ± 19.37) x 10–6 versus (23.6 ± 15.93) x 10–6, p = 0.003].
Conclusions: Primary graft dysfunction induces proinflammatory cytokines that can upregulate donor HLA-II antigens on the allograft. Increased donor HLA-II expression along with PGD-induced allograft inflammation promotes the development of donor specific alloimmunity. This provides an important mechanistic link between early posttransplant lung allograft injury and reported association with broncholitis obliterans syndrome.
|
Introduction |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
There is now accumulating evidence that early posttransplant events promote the development of BOS. In a previous study from our laboratory, we found that patients with BOS had elevated proinflammatory mediators including IP-10, MCP-1, interleukin (IL)-1β, IL-2, IL-12, and IL-15 during the early posttransplant interval [5]. The increase in proinflammatory mediators was associated with the development of donor-specific HLA class II alloimmunity. However, the cause of elevated proinflammatory cytokines in patients with BOS remained unclear. Recently, in a retrospective review of 334 adult lung transplant recipients, Hachem and colleagues [10] found that primary lung allograft dysfunction (PGD) was associated with increased risk of BOS (relative risk, 1.73 to 2.53), independent of acute rejection, lymphocytic bronchitis, and community-acquired respiratory viral infections. Primary graft dysfunction has been proposed to produce inflammation and amplify the immunogenicity of the allograft. Here, we hypothesized that PGD-induced inflammation upregulated major histocompatibility complex expression on the allograft, leading to increased alloantigen presentation and production of antidonor antibodies that are known to contribute to the immunopathogenesis of BOS.
|
Material and Methods |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
Definitions
Broncholitis obliterans syndrome was diagnosed according to the International Society for Heart and Lung Transplantation (ISHLT) criteria [11] based on the percentage decline in forced expiratory volume in 1 second (FEV1) compared with baseline and graded as follows: 1 = 80% to 66% of baseline value, 2 = 65% to 51% of baseline value, and 3 = 50% or less of baseline value. Other causes of decreased lung function such as infection and bronchial anastomotic stricture were ruled out.
Primary graft dysfunction was diagnosed immediately after transplant on arrival of the patient to the intensive care unit according to the established definition of the ISHLT [12]. Grade 0 is characterized by a partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) ratio greater than 300 mm Hg and a clear chest radiograph; grade 1 by a PaO2/FiO2 ratio greater than 300 mm Hg and radiographic infiltrates consistent with pulmonary edema; grade 2 by a PaO2/FiO2 ratio = 200 to 300 mm Hg and pulmonary infiltrates; and grade 3 by a PaO2/FiO2 ratio less than 200 mm Hg with pulmonary infiltrates. The absence of other potential causes of lung allograft dysfunction such as hyperacute rejection, venous anastomotic complications, cardiogenic pulmonary edema, and pneumonia are implicit in this definition.
Assays and Reagents
Flow-panel reactive antibodies (PRA) analysis for the detection of HLA antibodies was done using flow-cytometry as per the manufacturer's protocol (One Lambda, Canoga Park, California). The percent PRA is determined by the percent of microparticles that are bound by the antibodies in the serum. A PRA of 2.9% or greater for HLA class I and 2.4% for HLA class II was considered positive. Serum levels of IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-15, IL-17, Eotaxin, IP-10, MIG, MCP-1, MIP-1
, MIP-1β, RANTES, tumor necrosis factor (TNF)-, IFN-, IFN-, GM-CSF, IL-1R, and IL-2R were analyzed using the solid phase sandwich multiplex bead LUMINEX immunoassays (Biosource International, Carlsbad, California) according to the manufacturer's protocols. To detect donor specific anti-HLA class II CD4+ T-cell alloreactivity, we used peptides corresponding to the to the β-chain hypervariable region of the mismatched HLA-DR*0101, HLA-DR*0301, HLA-DR*0701, and HLA-DR*1501 (Research Genetics, Huntsville, Alabama) [8]. These techniques have been described in detail in our previous publication [5].
ELISPOT Assay
The ELISPOT assay for IFN- was performed as previously described [13]. ELISPOT is a recent technique to analyze the frequency of antigen-specific T cells in a given sample. Briefly, multiscreen 96-well filtration plates (Millipore, Billerica, Massachusetts) were coated with 5.0 µg/mL capture human cytokine-specific mAb (BD Biosciences) at 4°C overnight. The plates were then blocked with 1% BSA for 2 hours and washed with phosphate-buffered saline. Subsequently, 3 x 105 PBMCs were cultured in triplicate in the presence of donor HLA-DR peptides (10 µg/mL) and irradiated feeder autologous PBMCs (antigen presenting cells [APC]; 1:1 ratio). After 48 hours, the plates were washed, and then 2.0 µg/mL biotinylated human cytokine-specific mAb (BD Biosciences, San Jose, California) in PBS/BSA/Tween-20 was added to the wells. After an overnight incubation at 4°C, the plates were washed (three times) and horseradish peroxidase-labeled streptavidin (BD Biosciences), diluted 1:2000 in PBS/BSA/Tween-20, was added to the wells. After 2 hours, the assay was developed by 3-amino-9-ethylcarbazole substrate reagent (BD Biosciences) for 5 to 10 minutes. The plates were washed with tap water to stop the reaction and air dried. The spots were analyzed in an ImmunoSpot Series I analyzer (Cellular Technology, Shakey Heights, Ohio).
Statistical Analysis
Continuous data were checked for normality using the Shapiro-Wilk test. Nonnormal data were transformed with a log transformation. Type 1 error was controlled when performing multiple t tests using the Dunn-Sidak correction. Tabular data were compared using Fisher's exact test for 2 x 2 tables and 
2 for 2 x n tables. For more than two group comparisons and analyzing multiple dependent variables, multiple analysis of variance was used. The frequency of alloreactive T cells was compared between PGD0 and PGD1-3 patients using a two-tailed t test. Serial development of HLA antibodies on Flow-PRA was analyzed using the Kaplan-Meier analysis, and the groups were compared using the log-rank test.
|
Results |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
|
and IL-12; p < 0.05 for all; Fig 1B). Although there was a trend toward increased proinflammatory cytokines with higher grades of PGD, the differences were not statistically significant in this cohort (data not shown). There was no difference in the levels of IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-13, IL-15, IL-17, Eotaxin, MIG, MIP-1, MIP-1β, RANTES, TNF-, IFN-, GM-CSF, IL-1R, and IL-2R (data not shown).
|
|
ELISPOT assays. These HLA class II peptides are capable of stimulating CD4+ T cells after being presented on autologous APC. Therefore, they elicit an indirect alloreactive CD4+ T-cell response. Samples were selected after 90 days after transplant to avoid any confounding effects of induction immunosuppression as well as perioperative stress. The sampling time was similar between groups (PGD1-3 135 ± 35.0 days versus PGD0 125.4 ± 28.0 days, p = 0.6). Patients with PGD were found to have increased donor-specific HLA class II alloreactive IFN- producing CD4+ T cells compared with patients who did not have PGD [(91.4 ± 19.37) x 10–6 PBMC versus (23.6 ± 15.93) x 10–6 PBMC; p = 0.003). No difference was found in the frequency of CD4+ T cells reactive to a third-party (mumps) antigen (PGD1-3 35.7 ± 18.3 x 10–6 PBMC versus PGD0 24.1 ± 13.8 x 10–6 PBMC; p = 0.1). The response of 10 normal subjects (mean age, 29.7 ± 11.3 years; male:female ratio 6:4) to mumps antigen was not statistically different (25.5 ± 16.9 x 10–6 PBMC, p = 0.08). Taken together, these data indicate that PGD promotes the development of donor-specific HLA class II alloimmunity.
|
|
Comment |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
, IL-1β, IL-2, and IL-12 in the early posttransplant period supports this notion; IP-10 and MCP-1 belong to the CXC and CC family of chemokines, respectively, and have been previously implicated in allograft rejection [16, 17]. They are also known to upregulate HLA class I and II, costimulatory molecules such as CD80 and CD86 on immune cells, and cell adhesion molecules such as CD54 and CD58 on allograft airway epithelial cells [18]. In addition, they activate APC and Th1-lymphocytes [19] that can augment the inflammatory cascade by producing Th1-cytokines. Several studies published in the past have demonstrated an increase in proinflammatory cytokines in patients with PGD immediately after transplant [20, 21]. In this report, we included cytokine analysis done several weeks after PGD to demonstrate that these patients remain "immunologically charged" for a significant period after the initial injury. However, the duration that this inflammation lasts remain unknown from this present study. It is also unclear if other injury mechanisms such as acute rejection, gastroesophageal reflux disease, and respiratory infections propagate the inflammation. Further, the power of the present study was not sufficient enough to correlate the severity of PGD with cytokine levels. A larger study performed longitudinally would be important to address these questions.
Inflammatory mediators including IFN- and IL-2 can induce expression of HLA-class II antigens on donor vascular endothelium [22, 23]. We further found that IFN- significantly increased the expression of HLA class II antigens both on the larger (bronchial) as well as the small AEC (data not shown). Human and murine studies have demonstrated that donor airway epithelium may constitute the predominant target of BOS pathogenesis [9]. Upregulation of HLA class II molecules on donor cells in PGD patients can increase the donor antigen presentation to the recipient immune system promoting the expansion of alloreactive CD4+ T cells. The CD4+ T cells can further augment antidonor antibody development that was consistent with the higher incidence of de novo HLA class II alloantibody production observed in PGD patients (Fig 2). Additional inflammatory risk factors such as acute rejection, gastroesophageal reflux, and respiratory infections would further propagate donor-specific alloimmunity and promote ligation of HLA class II alloantibodies to AEC by up-regulating HLA class II antigens. Binding of the alloantibodies to the AEC can produce deleterious effects such as complement-mediated cytotoxicity, apoptosis, and production of stress proteins as well as growth factors that lead to smooth muscle cell proliferation and fibrosis [24]. The increased risk of BOS from HLA class II alloimmunity has been previously reported by our laboratory and others [5, 6, 8].
Human leukocyte antigen class I alloimmunity has also been strongly implicated in the pathogenesis of BOS [9]. However, in this study, we found that PGD did not significantly increase the development of HLA class I antibodies. The HLA class I antigens are constitutively expressed on somatic cells of the donor tissue, whereas HLA class II antigens are upregulated owing to inflammatory mediators during PGD. Primary graft dysfunction can be hypothesized to promote alloimmunity by increasing the donor antigen load and activating immune cells. Whereas in the case of donor HLA class II alloimmunity both mechanisms are effective, only the latter may play a role in the development of HLA class I alloimmunity. However, this does not exclude the role of HLA class I alloimmunity in the development of BOS. We postulate that, within the same PGD grade, patients with HLA class I antibodies would be more likely to develop BOS compared with patients without them. It is noteworthy that there was a higher incidence of HLA antibody development in this study compared with the previous reports [3, 25, 26]. This finding is most likely due to the longer and close follow-up of patients, combined with using the Flow-PRA technique, which is known to have higher sensitivity. We also noted that HLA antibodies developed after transplantation can disappear from the sera, most likely because of immunoadsorption at the allograft site. Therefore, cross-sectional or studies without close follow-up of patients may underestimate the development of HLA antibodies.
It is intriguing how PGD can impact the development of antibodies and BOS several years later. There are two pathways of alloantigen recognition: direct and indirect. In the direct pathway, the recipient T cells directly react with the donor antigens present on the donor APC (in context of the recipient major histocompatibility complex). In contrast, the indirect pathway involves recognition of processed donor antigens on recipient APC (in context of the recipient major histocompatibility complex). While the direct pathway is more important for acute allograft rejection, the indirect pathway is postulated to play a dominant role in chronic allograft rejection [27]. Interestingly, immunosuppressive agents are effective in depleting the direct alloreactive T cells but not the indirect alloreactive T cells [28]. The presence of donor HLA class II (indirect) alloreactive T cells in the early posttransplant period (Table 2) further supports this notion. The development of alloantibodies is dependent on CD4+ T-helper cells that recognize donor antigens through the indirect pathway. These indirectly alloreactive "effector" T cells in lung transplant patients remain suppressed by the naturally occurring CD4+CD25+foxp3+ regulatory T cells [29].
The long-term outcome after lung transplantation may depend on the balance of regulatory T cells and effector T cells. There are mechanisms that can lead to impairment of the regulatory T-cell function and lead to a favorable effector T-cell response. For example, the widely used calcineurin inhibitors block the production of IL-2, which is also crucial for regulatory T-cell function. Therefore, while effective in preventing acute rejection, the impact of calcineurin inhibitors on BOS has been limited. Recent data from our laboratory also demonstrate that respiratory viral infections induce apoptosis in regulatory T cells and promote chronic allograft rejection (manuscript under preparation). In addition, there are mechanisms that can augment inflammation, increase donor antigen load, and activate effector T cells. Besides PGD, these include acute rejection, gastroesophageal reflux, and respiratory viral infections that have been shown to correlate with increased incidence of BOS. Repeated injuries that produce allograft inflammation also lead to tissue remodeling and development of autoimmunity [29]. Both alloantibodies as well as autoantibodies have the ability to stimulate epithelial and endothelial cells and produce growth factors that result in the gradual process of luminal obliteration seen in BOS.
|
Discussion |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
One thing that would have made the paper more compelling would have been had you made the link more directly to the development of BOS. All patients in this paper had 2 to 17 years of follow-up, so it would have been possible to know precisely which patients with enhanced cytokine and alloimmune responses actually developed BOS. In two papers that your group published in the last year, one demonstrated an association between PGD and BOS and the other showed increased levels of cytokines in BOS-positive patients. First question: Are some of these patients included in the present study, or alternatively, do you know which patients in the present study actually went on to develop BOS?
The precise mechanism whereby an increase in selected proinflammatory cytokines leads to enhanced production of anti-HLA antibodies or donor class II specific T cells is unclear. The number of cytokines you measured that were not increased in PGD patients are also known to enhance class II antigen expression and promote rejection of other solid organ allografts. The ability of gamma interferon to induce relatively weak expression of class II antigens on cultured airway epithelial cell lines compared with, say, mononuclear cells may model a contributing factor but seems unlikely to be the centrally important mechanism whereby PGD enhances immunity. Furthermore, increased levels of IL-2 among PGD patients could signify an attempted expansion of Foxp3+ T regulatory cells. Second question: Why did you measure this battery of cytokines, and given the delay in antibody development, how specifically would you propose they lead to enhanced alloimmune responses?
It strikes me that the increased global inflammatory state would be expected to stimulate B-cells and produce a PRA response. Serial PRA assessed with flow beads with a cutoff of 3% is likely to pick up a lot of nonspecific reactivity, especially in the early posttransplant period. Did you verify that these indeed were anti-HLA antibodies perhaps with a single antigen assay, and were they IgG or IgM?
And finally, one might expect that over time with receptor editing we would see specific B-cell populations expand with production of higher affinity antibodies. Do you have any serial data that examine whether or not that occurs? Or stated differently, do you have any data on trends in the development of donor-specific anti-HLA class II antibodies? Once again, congratulations to you and your colleagues, and I would like to thank the Society for the privilege of discussing this very fine paper.
DR BHARAT: Thanks, Dr Mulligan, for those very interesting questions. Let me try and answer them in the same sequence. First of all, for these patients I did not present the data about the development of BOS in our study subjects because I felt that other studies have actually looked at it, and Dr Hachem's group clearly demonstrated an increased risk. So each of these patients was followed, and we have the data on who developed antibodies, and we also estimated the relative risk of developing BOS if you have PGD-associated inflammation, and the data correlate with Dr Hachem's study earlier. We found that patients who have any form of PGD have a relative risk of 1.8 of developing BOS ultimately.
The second question was about IL-2 and FoxP3. I think that is a very important point. Although I showed only five cytokines, we actually analyzed 25 different cytokines. So it is a very extensive cytokine assay that was performed looking at all clinically relevant cytokines, chemokines, and their receptors. In the interest of time, I had taken that data off. Interleukin-2 is a very interesting cytokine. Although it can promote FoxP3 development, it is also associated with the inflammatory response. And I think combined with the other inflammatory chemokines and cytokines, it tilts the favor towards the inflammatory pathway.
Now, these antibodies that we analyzed were detected by Flow-PRA, and they were not exactly donor specific. We test these by taking a panel of HLA antigens coated on beads and react them with the recipient sera. It is technically very challenging to look at donor-specific antibodies because you need to have donor T cells or some form of donor HLA available prospectively to test the recipient sera every single time, and from the figures it may be evident that some of these follow-ups were over a 10-year period. So it is very difficult to maintain that amount of donor tissue, and that is why Flow-PRA was used in this study, and this is becoming a commonly used technique to prospectively study patients for HLA antibodies.
DR DIMITRI NOVITZKY (Tampa, FL): In the University of Cape Town, we did extensive experimental studies inducing brain death by raising the endocranial pressure; this induced a short-lived but devastating catecholamine storm. Also significant endocrine changes were observed which eventually lead to inhibition of aerobic metabolism, thus adversely impacting on all organs used for transplantation. Brain death induces expression on the sarcommere of class I and class II antigens, and there is release of proinflammatory cytokines. Primary graft failure in the recipient in many instances is directly related to the brain dead effect on the organs while they were in the donor, such as the lungs, heart, liver, and so forth. Some patients die rapidly, such as in a car accident, or a gun shot into the head. Others die slowly, after undergoing multiple therapeutic interventions, for example, neurosurgical procedure, have blood transfusion, resuscitation, and so forth. All these events potentiate the inflammatory response in the future donor. I think that is essential to study the brain dead organ donor, the mechanism of death, for how long has been the donor brain dead. That may allow us to extrapolate the future organ function in the recipient.
Doctors Rose and Miller found in animal and clinical studies calcifications in the media of coronary arteries. Using von Kossa staining techniques, fine crystals of calcium can be appreciated. Chronic rejection of the heart is a chronic vascular degeneration that is initiated in the donor, and leads to microinfarcts in the recipient. Therefore, chronic rejection is a vascular disease that starts in the brain dead organ donor and is translated in the recipient. Do you have clinical data from the donors, and the mechanism leading to the death of the brain?
DR BHARAT: That is a very important point and we are just starting to understand that and look into the donor characteristics. Unfortunately, the way the study was planned, we did not expect this kind of finding and we did not collect all the donor data. But as a sequel to the study, we have started looking into that, and we are trying to see what donor characteristics can predispose to PGD. So that is something that we are working on now. It was not done for this study.
DR NOVITZKY: There is a very strong correlation between the donor and the recipient, and if you look at the brain death in an experimental fully instrumented animal, pulmonary artery pressure rises very high, the same as the left atrium, may reach up to 90 mmHg. That is enough to disrupt the endothelium in the lung.
DR BHARAT: Thank you very much for bringing up that point. Like I said, we are trying to look at the donor characteristics that can predispose to these early posttransplant events.
DR THOMAS M. BEAVER (Gainesville, FL): We have looked at the inflammatory cytokine response immediately after lung transplantation and were able to show graded elevations in the inflammatory response, for example, IL-6, IL-10, and the severity of the PGD response. You measured cytokines at 3 months, and I was just curious why you didn't measure them immediately postoperatively. I think your link of PGD to OB would be a little closer then.
DR BHARAT: We actually have data in the immediate posttransplant period as well, and I did not present that in the interest of time. The reason I chose to present these data was to make a point that these patients who have PGD immediately after transplant are still charged several months down the road, and that somehow perpetuates the development of alloimmunity. But you are absolutely right, we have actually looked at patients on the day of transplant and they have sky-high levels of the proinflammatory cytokines.
|
Acknowledgments |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
|
References |
|---|
|
TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  N. M. Walker, L. N. Badri, A. Wadhwa, S. Wettlaufer, M. Peters-Golden, and V. N. Lama Prostaglandin E2 As an Inhibitory Modulator of Fibrogenesis in Human Lung Allografts Am. J. Respir. Crit. Care Med., January 1, 2012; 185(1): 77 - 84. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Kreisel, S. Sugimoto, J. Zhu, R. Nava, W. Li, M. Okazaki, S. Yamamoto, M. Ibrahim, H. J. Huang, K. A. Toth, et al. Emergency granulopoiesis promotes neutrophil-dendritic cell encounters that prevent mouse lung allograft acceptance Blood, December 1, 2011; 118(23): 6172 - 6182. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Ahmad, O. A. Shlobin, and S. D. Nathan Pulmonary Complications of Lung Transplantation Chest, February 1, 2011; 139(2): 402 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Bharat, D. Saini, N. Steward, R. Hachem, E. P. Trulock, G. A. Patterson, B. F. Meyers, and T. Mohanakumar Antibodies to Self-Antigens Predispose to Primary Lung Allograft Dysfunction and Chronic Rejection Ann. Thorac. Surg., October 1, 2010; 90(4): 1094 - 1101. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Meloni and M. Strueber Early peri-operative care Lung Transplantation, June 7, 2010; 131 - 146. [Abstract] [Fulltext] [PDF]
|
|
|
|
|
|
V. N. Lama Update in Lung Transplantation 2008 Am. J. Respir. Crit. Care Med., May 1, 2009; 179(9): 759 - 764. [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. Lee and J. D. Christie Primary Graft Dysfunction Proceedings of the ATS, January 15, 2009; 6(1): 39 - 46. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
