Chronic lung allograft dysfunction post-lung transplantation: The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome

Proteomic Analysis of Transbronchial Biopsies to Discover Novel Biomarkers for Early Identification of Chronic Lung Allograft Dysfunction

Background

Chronic lung allograft dysfunction (CLAD) is a major contributor to poor long-term survival after lung transplantation (LTx). There is a paucity of validated tissue biomarkers which limits the early detection of CLAD. The aim of this study was to discover novel tissue proteins in CLAD.

Methods

A longitudinal cohort study analyzed 15 tissue specimens from 2 groups of bilateral LTx recipients; those with CLAD (n = 3) and those without CLAD (n = 3). In both groups, transbronchial biopsies (TBBx) were retrieved from 2 timepoints; stable surveillance at 90 d after transplant, and during episodes of acute lung allograft dysfunction. In the CLAD cohort, additional tissue from explant CLAD lungs collected at retransplantation was analyzed. Proteomics analysis and immunohistochemistry were used to identify and validate differentially expressed proteins.

Results

Tissue upregulation of a number of proteins including SerpinB1, SerpinH1, Cofilin 1, MUC1, COL15A1, COL4A4, and Coronin1B was found in recipients with CLAD. This finding was present when comparing CLAD onset and explant pathology to stable surveillance among recipients with CLAD and evident when compared with recipients without CLAD. Most of the upregulated tissue proteins in patients with CLAD had collectively critical roles in leukocytes migration and activation, inflammation, free radicals production and oxidative stress, epithelial-mesenchymal transition, myofibroblasts activation, and excessive deposition of extracellular matrix, which in turn enhance the risk of lung fibrosis and graft rejection. We also found exclusive expression of HLA-DQB1, JCHAIN, SAP18, FUCA1, MZB1, G3BP2, and BTF3 in CLAD cases, indicating they could be specific biomarkers of CLAD.

Conclusions

This study identifies distinct proteomes that are linked to CLAD development and consequently may be a useful indicator for identifying LTx patients at higher risk of CLAD.

Activation of anti-donor CD8 alloimmune response in clinically diagnosed acute rejection early after living-donor lobar lung transplantation and its impact on outcome

BACKGROUND

The characteristics and prognostic impacts of early graft infiltration after lung transplantation and clinically diagnosed acute rejection remain unclear. Furthermore, the alloimmune response status in lung transplantation remains uninvestigated.

METHODS

In this retrospective cohort study, we evaluated 92 living-donor lobar lung transplantations (LDLLT) to establish the effect of graft infiltration-diagnosed as acute rejection-within one-month post-transplantation (cAR), on chronic lung allograft dysfunction (CLAD)-free LDLLT survival. The alloimmune response was evaluated using the carboxyfluorescein diacetate succinimidyl ester (CFSE)-mixed lymphocyte reaction (MLR) in lymphocytes isolated from donor and recipient blood one week after LDLLT. The anti-donor proliferation of CD4+ and CD8+ T cells was determined using flow cytometry.

RESULTS

cAR was observed in 54 (58.7 %) patients who underwent LDLLT. The median postoperative day of cAR occurrence was 7 days (ranging between 5 and 28 days). Only one episode of cAR occurred in 51 patients (94.4 %). CLAD-free survival was significantly lower in patients who underwent cAR, especially within 2 years after LDLLT (p = 0.016). Thirteen CFSE-MLR assays were performed in seven consecutive LDLLT cases (six bilateral and one unilateral LDLLT). Increased anti-donor proliferation of CD8+ T cells, but not CD4+ T cells, was associated with cAR, irrespective of human leukocyte antigen (HLA) class I mismatch.

CONCLUSION

Early lung graft infiltration after LDLLT increases the risk of the early development of CALD. Augmented anti-donor CD8 + response was also associated with graft infiltration, which could not be predicted from HLA mismatches but could be monitored using MLR in LDLLT.

Triple role of exosomes in lung transplantation

Exosomes are tiny vesicles secreted by the vast majority of cells and play an important role in physiological as well as pathological processes in the body. Circulating exosomes in Lung Transplant Recipients (LTxR) undergoing rejection contain mismatched Human Leukocyte Antigens (HLA) and lung-associated autoantigens (e.g., K-alpha1 microtubule protein and collagen V), which may induce autoantibodies, and the circulating exosomes trigger an immune response that results in rejection of the lung transplant recipient. This article discusses the role of exosomes in lung transplantation from three perspectives: exosomes as a biomarker for rejection after lung transplantation; the mechanism of exosome-mediated activation of the immune response; and the potential of exosomes as a therapeutic strategy.

Evaluation of Complex Drug Interactions Between Elexacaftor-Tezacaftor-Ivacaftor and Statins Using Physiologically Based Pharmacokinetic Modeling

Background/Objectives: The increasing use of statins in people with cystic fibrosis (CF) necessitates the investigation of potential drug-drug interactions (DDI) of statins with cystic fibrosis transmembrane conductance regulator (CFTR) modulators, including elexacaftor, tezacaftor, and ivacaftor (ETI). The interactions may involve the potential inhibition of cytochrome P450 isoenzymes (CYPs), organic anion-transporting polypeptides (OATPs), and Breast Cancer Resistance Protein (BCRP) by ETI. This presents a therapeutic challenge in CF due to the potential for elevated statin levels, consequently heightening the risk of myopathy. This study aimed to predict potential DDIs between statins and ETI using a physiologically based pharmacokinetic (PBPK) modeling approach. Methods: We performed in vitro assays to measure the inhibitory potency of ETI against OATPs and CYP2C9 and incorporated these data into our PBPK models alongside published inhibitory parameters for BCRP and CYP3A4. Results: The PBPK simulation showed that atorvastatin had the highest predicted AUC ratio (3.27), followed by pravastatin (2.27), pitavastatin (2.24), and rosuvastatin (1.83). Conclusions: Based on these findings, rosuvastatin appears to exhibit a weak interaction with ETI, whereas other statins exhibited a moderate interaction, potentially requiring appropriate dose reductions. These data indicate potential clinically significant DDIs between ETI and certain statins, which warrants a clinical study to validate these findings.

Assessment of the Therapeutic Potential of Enhancer of Zeste Homolog 2 Inhibition in a Murine Model of Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans syndrome (BOS) is a chronic complication following lung transplantation that limits the long-term survival. Although the enhancer of zeste homolog 2 (EZH2) is involved in post-transplantation rejection, its involvement in BOS pathogenesis remains unclear. We aimed to investigate the therapeutic potential of EZH2 inhibition in BOS. 3-deazaneplanocin A (DZNep) was administered intraperitoneally to heterotopic tracheal transplant recipient model mice. Tracheal allografts were obtained on days 7, 14, 21, and 28 after transplantation. The obstruction ratios of the DZNep and control groups on days 7, 14, 21, and 28 were 15.1% ± 0.8% vs. 20.4% ± 3.6% (p = 0.996), 16.9% ± 2.1% vs. 67.7% ± 11.5% (p < 0.001), 47.8% ± 7.8% vs. 92.2% ± 5.4% (p < 0.001), and 60.0% ± 9.6% vs. 95.0% ± 2.3% (p < 0.001), respectively. The levels of interleukin (IL)-6 and interferon-γ on day 7 and those of IL-2, tumor necrosis factor, and IL-17A on days 14, 21, and 28 were significantly reduced following DZNep treatment. DZNep significantly decreased the number of infiltrating T-cells on day 14. In conclusion, DZNep-mediated EZH2 inhibition suppressed the inflammatory reactions driven by pro-inflammatory cytokines and T cell infiltration, thereby alleviating BOS symptoms.

Differences in chronic lung allograft dysfunction between deceased-donor lung transplantation and living-donor lobar lung transplantation

OBJECTIVE

To explore the characteristics and prognostic impact of chronic lung allograft dysfunction (CLAD) after deceased-donor lung transplantation and living-donor lobar lung transplantation, wherein the lower lobes from 2 donors are usually transplanted into one recipient.

METHODS

The clinical data of 123 deceased-donor and 67 living-donor lung transplantations performed in adult patients at our institution between June 2008 and September 2019 were retrospectively reviewed. The cumulative incidence of CLAD was evaluated on a per-recipient and per-donor graft basis using the Kaplan-Meier method.

RESULTS

A smaller number of human leukocyte antigen mismatches, shorter ischemic time, and lower incidence of grade 3 primary graft dysfunction were observed in living-donor transplantation than in deceased-donor transplantation (P < .001). Restrictive allograft syndrome-type CLAD occurred in 9 (20.9%) of 43 patients with CLAD after deceased-donor transplantation and 9 (45.0%) of 20 patients with CLAD after living-donor transplantation. CLAD occurred unilaterally in 15 patients (75.0%) after bilateral living-donor transplantation. Despite the greater incidence of restrictive allograft syndrome-type CLAD after living-donor transplantation, the overall survival rates after the transplantation and survival rates after the onset of CLAD were comparable between the patients receiving deceased-donor transplants and living-donor transplants. The cumulative incidence of CLAD per recipient was similar between recipients of deceased-donor and the living-donor transplants (P = .32). In the per-donor graft analysis, the cumulative incidence of CLAD was significantly lower in the living-donor grafts than in the deceased-donor grafts (P = .003).

CONCLUSIONS

The manifestation of CLAD after living-donor lobar lung transplantation is unique and differs from that after deceased-donor lung transplantation.

A Complement to Traditional Treatments for Antibody-Mediated Rejection? Use of Eculizumab in Lung Transplantation: A Review and Early Center Experience

OBJECTIVE

To review the efficacy and safety of eculizumab for prevention and treatment of antibody-mediated rejection (AMR) in lung transplant recipients (LTRs).

DATA SOURCES

A literature search of PubMed and the Cochrane Controlled Trials Register (2007 to mid-October 2023) was performed using the following search terms: eculizumab, complement inhibitor, solid organ transplant, lung transplant, and AMR.

STUDY SELECTION AND DATA EXTRACTION

All relevant English-language studies were reviewed and considered.

DATA SYNTHESIS

Eculizumab, a monoclonal antibody that binds complement protein C5 to inhibit its cleavage and subsequent generation of the membrane attack complex, is currently approved to treat paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, generalized myasthenia and neuromyelitis optica spectrum disorder. Given the role of antibodies directed against donor antigens that are produced by allospecific B-cells and plasma cells in AMR, eculizumab is being investigated for use within this indication. Three case reports have described the successful use of eculizumab for the prevention and treatment of AMR in LTRs. Given this lack of robust data, evidence for the use of eculizumab in other solid organ transplant recipients is of increased value. Early experiences from a single center's use of eculizumab in LTRs are also described.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Lung transplant is a recognized treatment for end-stage lung disease, though complications posttransplant can be associated with significant morbidity and mortality. While prevention and management of AMR remains a substantial challenge without comprehensive guidance from societal guidelines, recently published literature may be helpful to guide clinical practice using alternative treatment options. However, this remains an area of great clinical importance, given the impact of AMR on long-term allograft function.

CONCLUSIONS

Optimizing use of current therapies, as well as identifying and advancing novel therapeutic modalities such as eculizumab, are vital for the improvement of AMR prevention and treatment in LTRs to extend long-term allograft function and survival.

IL-33: Friend or foe in transplantation?

Several reports have highlighted the dichotomous nature of the Interleukin-33 (IL-33) system in cardiac and lung disease, where this cytokine can exert both protective effects and drive pro-inflammatory responses in a context-specific manner. This State-of-the-Art review focuses on preclinical mechanistic studies of the IL-33 system in development of allograft rejection in heart and lung transplantation. We address the scope of potential cellular sources of IL-33 and pathways for cellular release that may impact the study of this cytokine system in transplant models. We then highlight soluble IL-33 receptor as a biomarker in cardiac allograft rejection and detail preclinical models that collectively demonstrate a role for this cytokine in driving type-2 immune programs to protect cardiac allografts. We contrast this with investigation of IL-33 in lung transplantation, which has yielded mixed and somewhat conflicting results when comparing human studies with preclinical models, which have implicated the IL-33 system in both allograft tolerance and acceleration of chronic rejection. We summarize and interpret these results in aggregate and provide future directions for study of IL-33 in heart and lung transplantation.

Imaging of Small Airways Disease

Bronchiolitis refers to a small airways disease and may be classified by etiology and histologic features. In cellular bronchiolitis inflammatory cells involve the small airway wall and peribronchiolar alveoli and manifest on CT as centrilobular nodules of solid or ground glass attenuation. Constrictive bronchiolitis refers to luminal narrowing by concentric fibrosis. Direct CT signs of small airway disease include centrilobular nodules and branching tree-in-bud opacities. An indirect sign is mosaic attenuation that may be exaggerated on expiratory CT and represent air trapping. Imaging findings can be combined with clinical and pathologic data to facilitate a more accurate diagnosis.

Fibrotic progression from acute cellular rejection is dependent on secondary lymphoid organs in a mouse model of chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) remains one of the major limitations to long-term survival after lung transplantation. We modified a murine model of CLAD and transplanted left lungs from BALB/c donors into B6 recipients that were treated with intermittent cyclosporine and methylprednisolone postoperatively. In this model, the lung allograft developed acute cellular rejection on day 15 which, by day 30 after transplantation, progressed to severe pleural and peribronchovascular fibrosis, reminiscent of changes observed in restrictive allograft syndrome. Lung transplantation into splenectomized B6 alymphoplastic (aly/aly) or splenectomized B6 lymphotoxin-β receptor-deficient mice demonstrated that recipient secondary lymphoid organs, such as spleen and lymph nodes, are necessary for progression from acute cellular rejection to allograft fibrosis in this model. Our work uncovered a critical role for recipient secondary lymphoid organs in the development of CLAD after pulmonary transplantation and may provide mechanistic insights into the pathogenesis of this complication.

Cell-Free DNA Maps Tissue Injury and Correlates with Disease Severity in Lung Transplant Candidates

Rationale: Plasma cell-free DNA levels correlate with disease severity in many conditions. Pretransplant cell-free DNA may risk stratify lung transplant candidates for post-transplant complications. Objectives: To evaluate if pretransplant cell-free DNA levels and tissue sources identify patients at high risk of primary graft dysfunction and other pre- and post-transplant outcomes. Methods: This multicenter, prospective cohort study recruited 186 lung transplant candidates. Pretransplant plasma samples were collected to measure cell-free DNA. Bisulfite sequencing was performed to identify the tissue sources of cell-free DNA. Multivariable regression models determined the association between cell-free DNA levels and the primary outcome of primary graft dysfunction and other transplant outcomes, including Lung Allocation Score, chronic lung allograft dysfunction, and death. Measurements and Main Results: Transplant candidates had twofold greater cell-free DNA levels than healthy control patients (median [interquartile range], 23.7 ng/ml [15.1-35.6] vs. 12.9 ng/ml [9.9-18.4]; P < 0.0001), primarily originating from inflammatory innate immune cells. Cell-free DNA levels and tissue sources differed by native lung disease category and correlated with the Lung Allocation Score (P < 0.001). High pretransplant cell-free DNA increased the risk of primary graft dysfunction (odds ratio, 1.60; 95% confidence interval [CI], 1.09-2.46; P = 0.0220), and death (hazard ratio, 1.43; 95% CI, 1.07-1.92; P = 0.0171) but not chronic lung allograft dysfunction (hazard ratio, 1.37; 95% CI, 0.97-1.94; P = 0.0767). Conclusions: Lung transplant candidates demonstrate a heightened degree of tissue injury with elevated cell-free DNA, primarily originating from innate immune cells. Pretransplant plasma cell-free DNA levels predict post-transplant complications.

Unique Changes in the Lung Microbiome following the Development of Chronic Lung Allograft Dysfunction

The importance of lung microbiome changes in developing chronic lung allograft dysfunction (CLAD) after lung transplantation is poorly understood. The lung microbiome-immune interaction may be critical in developing CLAD. In this context, examining alterations in the microbiome and immune cells of the lungs following CLAD, in comparison to the lung condition immediately after transplantation, can offer valuable insights. Four adult patients who underwent lung retransplantation between January 2019 and June 2020 were included in this study. Lung tissues were collected from the same four individuals at two different time points: at the time of the first transplant and at the time of the explantation of CLAD lungs at retransplantation due to CLAD. We analyzed whole-genome sequencing using the Kraken2 algorithm and quantified the cell fractionation from the bulk tissue gene expression profile for each lung tissue. Finally, we compared the differences in lung microbiome and immune cells between the lung tissues of these two time points. The median age of the recipients was 57 years, and most (75%) had undergone lung transplants for idiopathic pulmonary fibrosis. All patients were administered basiliximab for induction therapy and were maintained on three immunosuppressants. The median CLAD-free survival term was 693.5 days, and the median time to redo the lung transplant was 843.5 days. Bacterial diversity was significantly lower in the CLAD lungs than at transplantation. Bacterial diversity tended to decrease according to the severity of the CLAD. Aerococcus, Caldiericum, Croceibacter, Leptolyngbya, and Pulveribacter genera were uniquely identified in CLAD, whereas no taxa were identified in lungs at transplantation. In particular, six taxa, including Croceibacter atlanticus, Caldiserium exile, Dolichospermum compactum, Stappia sp. ES.058, Kinetoplastibacterium sorsogonicusi, and Pulveribacter suum were uniquely detected in CLAD. Among immune cells, CD8+ T cells were significantly increased, while neutrophils were decreased in the CLAD lung. In conclusion, unique changes in lung microbiome and immune cell composition were confirmed in lung tissue after CLAD compared to at transplantation.

Readmissions and costs in cadaveric and living-donor lobar lung transplantation: Analysis using a national database

Living-donor lobar lung transplantation (LDLLT) is a well-established surgical procedure with favorable outcomes; however, the frequency of readmission and costs in LDLLT are poorly understood. Here, we aimed to compare health care costs and readmissions at 90 days and 1 year after the index discharge in LDLLT and cadaveric lung transplantation (CLT) and evaluate the reasons for readmission and in-hospital mortality. In this retrospective cohort study, we used the Diagnosis Procedure Combination database, a nationwide inpatient database in Japan to obtain initial lung transplantation data for all patients from July 2010 to March 2020. Multivariable Poisson or multiple regression analyses after multiple imputation was performed to compare the cumulative number of readmissions and costs between patients receiving LDLLT and CLT. Among 514 recipients, 115 (22%) underwent LDLLT and 399 (78%) received CLT. Overall, in-hospital mortality after transplantation was 4.5%. The LDLLT group showed a significantly lower crude readmission rate (90 days, 22% vs 37%, p = 0.004; 1 year, 48% vs 62%, p = 0.031) and median readmission cost (90 days, United States dollar (USD) 0 vs 0, p = 0.003; 1 year, USD 1178 vs 4714, p = 0.005) than the CLT group. Multivariable regression analyses showed that the LDLLT group had a lower risk of readmission (incidence rate ratio, 0.59; 95% confidence interval, 0.38-0.92; p = 0.020) and lower costs at 90 days (difference, USD -11,629; 95% confidence interval, -5682 to -17,462; p < 0.001). The most frequent cause of readmission was pneumonia in both groups. LDLLT was associated with lower readmissions and health care costs in comparison with CLT. Our findings provide a scientific basis for further studies with larger cohorts.

Lung Transplantation From Controlled and Uncontrolled Donation After Circulatory Death (DCD) Donors With Long Ischemic Times Managed by Simple Normothermic Ventilation and Ex-Vivo Lung Perfusion Assessment

Donation after cardiac death (DCD) donors are still subject of studies. In this prospective cohort trial, we compared outcomes after lung transplantation (LT) of subjects receiving lungs from DCD donors with those of subjects receiving lungs from donation after brain death (DBD) donors (ClinicalTrial.gov: NCT02061462). Lungs from DCD donors were preserved in-vivo through normothermic ventilation, as per our protocol. We enrolled candidates for bilateral LT ≥14 years. Candidates for multi-organ or re-LT, donors aged ≥65 years, DCD category I or IV donors were excluded. We recorded clinical data on donors and recipients. Primary endpoint was 30-day mortality. Secondary endpoints were: duration of mechanical ventilation (MV), intensive care unit (ICU) length of stay, severe primary graft dysfunction (PGD3) and chronic lung allograft dysfunction (CLAD). 121 patients (110 DBD Group, 11 DCD Group) were enrolled. 30-day mortality and CLAD prevalence were nil in the DCD Group. DCD Group patients required longer MV (DCD Group: 2 days, DBD Group: 1 day, p = 0.011). ICU length of stay and PGD3 rate were higher in DCD Group but did not significantly differ. LT with DCD grafts procured with our protocols appears safe, despite prolonged ischemia times.

Immune processes in the pathogenesis of chronic lung allograft dysfunction: identifying the missing pieces of the puzzle

Lung transplantation is the optimal treatment for selected patients with end-stage chronic lung diseases. However, chronic lung allograft dysfunction remains the leading obstacle to improved long-term outcomes. Traditionally, lung allograft rejection has been considered primarily as a manifestation of cellular immune responses. However, in reality, an array of complex, interacting and multifactorial mechanisms contribute to its emergence. Alloimmune-dependent mechanisms, including T-cell-mediated rejection and antibody-mediated rejection, as well as non-alloimmune injuries, have been implicated. Moreover, a role has emerged for autoimmune responses to lung self-antigens in the development of chronic graft injury. The aim of this review is to summarise the immune processes involved in the pathogenesis of chronic lung allograft dysfunction, with advanced insights into the role of innate immune pathways and crosstalk between innate and adaptive immunity, and to identify gaps in current knowledge.

Lung Retransplantation

Lung retransplantation remains the standard treatment of irreversible lung allograft failure. The most common indications for lung retransplantation are acute graft failure, chronic lung allograft dysfunction, and postoperative airway complications. Careful patient selection with regards to indications, anatomy, extrapulmonary organ dysfunction (specifically renal dysfunction), and immunologic consideration are of utmost importance. The conduct of the lung retransplantation operation is arduous with special considerations given to operative approach, type of surgery (single vs bilateral), use of extracorporeal circulatory support, and hematological management. Outcomes have improved significantly for most patients, nearing short and midterm outcomes of primary lung recipients in select cases.

Allograft Dysfunction After Lung Transplantation for COPA Syndrome: A Case Report and Literature Review

COPA syndrome is an autoinflammatory disease with autoimmune and autoinflammatory manifestations affecting lungs, joints, and kidneys. COPA syndrome is caused by heterozygous loss-of-function mutations in the coatmer subunit alpha (COPA) gene, encoding α subunit of coatmer protein complex I (COP-I) coated vesicles. Mutant COPA induces constitutive activation of stimulator of interferon (IFN) genes (STING), leading to systemic inflammation and elevated type I interferon response. We have previously reported a Japanese family of COPA syndrome with a novel V242G mutation. Two out of 4 patients required lung transplantation due to intractable interstitial lung disease (ILD) and respiratory failure. Both of them deceased after lung transplantation, one due to sepsis and the other due to allograft dysfunction possibly caused by the reccurent ILD. The literature review indentified unfavorable outcome of the solid organ transplant in COPA syndrome and its related disease, however, precise clinico-pathological description of these cases has been scarce. Here, we report in detail the clinical course of our cases to clarify the pathophysiology of allograft dysfunction in COPA syndrome and propose potential therapeutic approaches to improve post-transplant graft survival.

Graft dysfunction and rejection of lung transplant, a review on diagnosis and management

Introduction

Lung transplantation has proven to be an effective treatment option for end‐stage lung disease. However, early and late complications following transplantation remain significant causes of high mortality.

Objectives

In this review, we focus on the time of onset in primary graft dysfunction and rejection complications, as well as emphasize the role of imaging manifestations and pathological features in early diagnosis, thus assisting clinicians in the early detection and treatment of posttransplant complications and improving patient quality of life and survival.

Data source

We searched electronic databases such as PubMed, Web of Science, and EMBASE. We used the following search terms: lung transplantation complications, primary graft dysfunction, acute rejection, chronic lung allograft dysfunction, radiological findings, and diagnosis and treatment.

Conclusion

Primary graft dysfunction, surgical complications, immune rejection, infections, and neoplasms represent major posttransplant complications. As the main posttransplant survival limitation, chronic lung allograft dysfunction has a characteristic imaging presentation; nevertheless, the clinical and imaging manifestations are often complex and overlap, so it is essential to understand the temporal evolution of these complications to narrow the differential diagnosis for early treatment to improve prognosis.

Early and late complications after lung transplantation remain essential causes of high mortality. In this review, we focus on the timing of the onset of primary graft dysfunction and rejection complications and highlight the role of imaging manifestations and clinicopathologic features in early diagnosis, thus assisting clinicians in the early detection and treatment of posttransplant complications and improving patient quality of life and survival.