Increased bronchoalveolar lavage human beta-defensin type 2 in bronchiolitis obliterans syndrome after lung transplantation

Human beta-defensin-2 (HBD)2 is an antimicrobial peptide that participates in the innate host immune defense. HBD2 is present in bronchoalveolar lavage (BAL) fluid during conditions associated with airway inflammation but not in normal subjects. We measured HBD2 concentrations by semiquantitative Western analysis in BAL of prelung transplant patients (PRE) and postlung-transplant BAL associated with either "quiescent" histopathology (i.e., without acute cellular rejection or infection) (NORMAL POST) or with bronchiolitis obliterans syndrome (BOS). HBD2 levels were not different for PRE (n=9) versus NORMAL POST-transplant BAL specimens (n=22) (204+/-180 vs. 82+/-60 pg/mL; P=NS). The BAL HBD2 concentrations were significantly elevated, however, with BOS (n=8) (1,270+/-430 pg/mL; P<0.001). HBD2 has been previously shown to elicit an adaptive immune response by means of recruitment of immature CD34 dendritic cells and memory (CD4/CD45RO) T lymphocytes through interactions with their chemokine receptor, CCR6. Furthermore, HBD2 with CD14 in human tracheobronchial epithelium can complex with "toll-like receptors" to activate the nuclear factor (NF)-kappaB pathway and therefore promote cytokine gene expression. We therefore speculate that complex interactions between adaptive and innate immunity may contribute to the propagation of airway inflammation in BOS.     

Clarithromycin for prevention of bronchiolitis obliterans syndrome in lung allograft recipients

Dhillon GS, Valentine VG, Levitt J, Patel P, Gupta MR, Duncan SR, Seoane L, Weill D. Clarithromycin for prevention of bronchiolitis obliterans syndrome in lung allograft recipients.
Clin Transplant 2012: 26: 105–110.
© 2011 John Wiley & Sons A/S. Abstract: Background: Bronchiolitis obliterans syndrome (BOS) is the major limitation to long‐term survival following lung transplantation and strategies to reduce its incidence have remained elusive. Macrolides may stabilize lung function in patients with established BOS. Their role, however, in prevention of BOS remains unexamined. Methods: Survival and BOS‐free survival of 102 lung allograft recipients (LARs), transplanted at a single center between July 1995 and December 2001 who routinely received clarithromycin, were compared with two different control groups. The first control group consisted of 44 LARs from the same center who were transplanted from January 2002 onwards and did not receive clarithromycin. The second control group consisted of a contemporaneous cohort of 5089 recipients, transplanted between 1995 and 2001, reported to the United Network for Organ Sharing database. Results: When compared with the first control group, BOS‐free survival was reduced in LARs receiving clarithromycin. Univariate (hazard ratio [HR] 3.13, p‐value = 0.004) and multivariate (HR 3.49, p‐value = 0.04) analyses showed that routine use of clarithromycin was associated with an increased risk of developing BOS. When compared with the second control group, the five‐yr survival of clarithromycin group was similar (p‐value = 0.24). Conclusions: Routine use of clarithromycin does not delay development of BOS or improve survival.     

Cytomegalovirus infection accelerates obliterative bronchiolitis of rat tracheal allografts

Abstract  A cascade of inflammation and injury of the airway wall followed by a fibroproliferative process that results in airway obstruction has been suggested as the explanation of the process of obliterative bronchiolitis (OB) in lung al-lograft recipients. To determine the impact of rat cytomegalovirus (RCMV) infection on the development of OB, heterotopic rat tracheal allografts were transplanted from DA donors to WF recipients im-munosuppressed with 2 mg/kg per day cyclosporine A. Chronic RCMV infection was similarly established 8 weeks before transplantation in donors alone (D +/R -), recipients alone (D-/R+), and both donors and recipients (D+/R+). The control rats were left non-infected, but were similarly immunosuppressed. The results of this study demonstrate that both acute and chronic recipient RCMV infection, but not donor infection, amplify the development of experimental OB in the rat and suggest that RCMV infection-associated immune response, rather than the viral load in the graft, is essential for the development of the accelerated form of OB.     

Quality of life and bronchiolitis obliterans syndrome in patients after lung transplantation

BACKGROUND: Lung transplantation has become an established and effective treatment for patients with end-stage pulmonary disease. OBJECTIVE: To investigate health-related quality of life in correlation with occurrence and degree of bronchiolitis obliterans syndrome after transplantation. METHODS: In a cross-sectional study design, 119 consecutive lung transplant recipients (63.9% bilateral and 36.1% single lung transplants) responded voluntarily to a set of standardized questionnaires (12-Item Short-Form Health Survey, Center for Epidemiologic Studies-Depression Scale, Coping With Everyday Life, Beck Anxiety Inventory, Zerssen list of complaints) that covered health-related quality of life and psychological well being. Also, we performed pulmonary function studies to clinically grade bronchiolitis obliterans syndrome in all patients. RESULTS: In this cohort, 41.2% of patients developed bronchiolitis obliterans syndrome at a mean interval of 5.6 years after lung transplantation. Actuarial freedom from bronchiolitis obliterans syndrome was 90.1% +/- 2.3% at 1 year, 79.9% +/- 3.7% at 3 years, and 59.5% +/- 4.8% at 5 years after lung transplantation. Recipients with bronchiolitis obliterans syndrome reported significantly lower well being and quality of life than those without bronchiolitis obliterans syndrome, who scored similar to healthy volunteers. In a subanalysis, body functioning (P < .001) and related areas of coping (P < .001) were mostly affected by bronchiolitis obliterans syndrome. CONCLUSIONS: Quality of life was negatively affected by the onset of bronchiolitis obliterans syndrome. However, even patients who develop bronchiolitis obliterans syndrome reported a temporary benefit from lung transplantation. In addition to optimal medical care and efforts in preventing bronchiolitis obliterans syndrome, psychological support of lung recipients seems to be essential, especially when bronchiolitis obliterans syndrome occurs.     

Airway neutrophilia in stable and bronchiolitis obliterans syndrome patients following lung transplantation

BACKGROUND: The bronchiolitis obliterans syndrome (BOS) remains the major constraint on the long term success of lung transplantation. Neutrophils have been associated with fibrosing lung conditions and have been noted to be increased in the bronchoalveolar lavage (BAL) fluid of patients with BOS. METHODS: This study was undertaken to examine neutrophil accumulation in the BAL fluid, airway wall and lung parenchyma, as well as levels of interleukin (IL)-8 in the BAL fluid, in normal controls and lung transplant recipients with and without BOS. Bronchoscopic examination included endobronchial biopsy (EBB), BAL fluid, and transbronchial biopsy (TBB) sampling. Tissue neutrophils were identified by neutrophil elastase staining on 3 microm paraffin biopsy sections and quantified by computerised image analyser. IL-8 levels were measured in unconcentrated BAL fluid by ELISA. RESULTS: Compared with controls, airway wall neutrophilia was increased in both stable lung transplant recipients and those with BOS (p<0.05). BAL neutrophils and IL-8 levels were also increased in both groups of transplant recipients compared with controls (p<0.01), the levels being significantly higher in the BOS group (p<0.01). Neutrophil numbers in the lung parenchyma were not significantly different between the two groups of lung transplant recipients. CONCLUSION: Increased levels of neutrophils are present in the airway wall and BAL fluid of lung transplant recipients with and without BOS. BAL fluid levels of IL-8 are also increased, raising the possibility that neutrophils and/or IL-8 may play a part in the pathogenesis of BOS following lung transplantation.     

Development of bronchiolitis obliterans syndrome despite blood chimerism in human lung transplant recipients

Bronchiolitis Obliterans Syndrome (BOS) remains the overwhelming obstacle to the success of lung transplantations (LTx). The presence of donor-specific microchimerism (DSM) and its association with lung allograft function is not well defined. To investigate the relationship between chimerism and BOS, blood was obtained from 21 LTx recipients. Genomic DNA was isolated from patient blood, and PCR-based techniques were used to identify recipient and donor HLA-DR. Fifty percent of the LTx recipients with BOS exhibited DSM at “T₁” time post transplant, and 40 % at one year follow-up (T₂). However, 54 % exhibited DSM in the BOS-free group at T₁, and 44 % at T₂. Of the BOS-free, DSM-positive patients at T₁, 29 % developed BOS by T₂. In contrast, 50 % of BOS-free DSM-negative patients 50 % developed BOS (P > 0.05). Double LTx had a higher prevalence of DSM (73 %) and a lower prevalence of BOS (46 %) than single LTx (50 % and 80 % respectively, P > 0.05). One-HLA-DR-antigen-matched LTx recipients show a low prevalence of DSM compared to non-matched (P < 0.05). This study demonstrates that the development of BOS in LTx recipients could also occur in the presence of blood chimerism. Received: 10 February 1999 Received after revision: 29 July 1999 Accepted: 1 September 1999     

Humoral immune responses in the pathogenesis of bronchiolitis obliterans syndrome after lung transplantation

Lung transplantation is recognized as a viable treatment option in a variety of end-stage pulmonary diseases. However, the long-term survival is limited by the development of bronchiolitis obliterans syndrome (BOS). Bronchiolitis obliterans syndrome occurs in more than half of lung transplant recipients who survive more than 5 years and is the leading cause of death in the late posttransplantation period. The specific etiology and pathogenesis of BOS are not well understood. The current premise is that BOS represents a common lesion in which different inflammatory insults such as ischemia-reperfusion, rejection, and infection can lead to a similar histological and clinical outcome. However, the observation that early development of BOS is predicted by the frequency and severity of acute rejection episodes indicates that alloimmune-dependent mechanisms play a crucial role in the pathogenesis of BOS. The evidence presented in this review will demonstrate that BOS is the result of indolent humoral immune responses developed against major histocompatibility complex molecules expressed by airway epithelial cells of the lung allograft. Currently, treatment of BOS is rarely successful. Therefore, a better understanding of the immunopathogenesis of BOS is of paramount importance toward improving long-term graft function and patient survival after lung transplantation.     

Bile acid aspiration and the development of bronchiolitis obliterans after lung transplantation

BACKGROUND: Aspiration of gastroesophageal refluxate may contribute to lung transplant bronchiolitis obliterans syndrome (BOS). We investigated bile acids in bronchoalveolar lavage fluid (BALF) and studied its role in BOS. MATERIALS AND METHODS: Surveillance pulmonary function tests and BALF were evaluated in 120 lung recipients. BOS-(0p-3) was diagnosed after 6 months' survival. BOS was defined as "early" if diagnosed within 12 months after a transplant. BALF was assayed for differential cell count, bile acids, and interleukins 8 and 15. Bile acids were considered elevated if greater than normal serum levels ( or =8 micromol/L). RESULTS: Elevated BALF bile acids were measured in 20 (17%) of 120 patients. BOS was diagnosed in 36 (34%) of 107 patients and judged "early" in 21 (57%) of 36. Median BALF bile acid values were 1.6 micromol/L (range, 0-32 micromol/L) in BOS patients and 0.3 micromol/L (range, 0-16 micromol/L) in non-BOS patients ( P = .002); 2.6 micromol/L (range, 0-32 micromol/L) in early BOS patients and 0.8 micromol/L (range, 0-4.6 micromol/L) in late BOS patients, ( P = .02). Bile acids correlated with BALF IL-8 and alveolar neutrophilia (r = 0.3, P = .0004, and r = 0.3, P = .004, respectively), but not with IL-15. Freedom from BOS was significantly shortened in patients with elevated BALF bile acids (Cox-Mantel test, P = .0001). CONCLUSIONS: Aspiration of duodenogastroesophageal refluxate is prevalent after lung transplantation and is associated with the development of BOS. Elevated BALF bile acids may promote early BOS development via an inflammatory process, possibly mediated by IL-8 and alveolar neutrophilia.     

Ischemia-reperfusion injury after lung transplantation increases risk of late bronchiolitis obliterans syndrome

BACKGROUND: Bronchiolitis obliterans syndrome (BOS) is the most common cause of long-term morbidity and mortality after lung transplantation. Our hypothesis was that early ischemia-reperfusion injury after lung transplantation increases the risk of BOS. METHODS: Data on 134 patients who had lung transplantation between January 1, 1990 and January 1, 2000, was used for univariate and multivariate logistic regression analysis. RESULTS: After lung transplantation, 115 patients (115 of 134, 86%) survived more than 3 months. In that group, 41 patients developed BOS, of which 23 had progressive disease. Univariate analysis revealed that ischemia-reperfusion injury (p = 0.017) and two or more acute rejection episodes (p = 0.032) were predictors of BOS onset, whereas ischemia-reperfusion injury (p = 0.011) and cytomegalovirus infection (p = 0.009) predicted progressive BOS. Multivariate logistic regression analysis showed that ischemia-reperfusion injury was an independent predictor for both BOS development and BOS progression. Two or more acute rejection episodes were also an independent predictor of BOS development, whereas cytomegalovirus infection was an independent predictor of progressive BOS. CONCLUSIONS: Ischemia-reperfusion injury increases the risk of BOS after lung transplantation.     

The role of soluble and insoluble gastric fluid components in the pathogenesis of obliterative bronchiolitis in rat lung allografts

Repetitive gastric fluid aspirations have been shown to lead to obliterans bronchiolitis (OB), but the component or components of gastric fluid that are responsible are unknown. This study investigates the role of particulates and, separately, soluble material in gastric fluid during the development of OB. Whole gastric fluid (WGF) was collected from male Fischer 344 (F344) rats and separated by centrifugation into particle reduced gastric fluid (PRGF) and particulate components resuspended in normal saline (PNS). Orthotopic left lung transplants from male Wistar–Kyoto rats into F344 rats were performed using a modification of the nonsuture external cuff technique with prolonged cold ischemia. Rats were subjected to weekly aspiration of 0.5 ml/kg of WGF (n = 9), PRGF (n = 10), PNS (n = 9), or normal saline (control, NS; n = 9) for 8 weeks following transplantation. Lung allografts treated with WGF, PRGF, or PNS developed a significantly greater percentage of OB‐like lesions compared with the control. No statistical difference was observed when comparing the fibrosis grades or the percentage of OB lesions of WGF, PRGF, and PNS groups, suggesting that both soluble and insoluble components of gastric fluid can promote the development of aspiration‐induced OB and fibrosis in lung allografts.     

Restoration of tolerance to rat hepatic allografts by spleen-derived passenger leukocytes

The tolerance induced by orthotopic liver transplantation (OLT) in certain combinations of rat strains can be prevented by total body irradiation (TBI) of the donor. We demonstrate here that the intravenous inoculation of splenic leukocytes into irradiated donors before OLT could re-establish tolerance in association with a state of microchimerism detected in the recipients. When donor DA (RT1^a) strain rats were irradiated with 1000 rad 24 h before liver harvesting and subsequent liver implantation into PVG recipients, five out of six rats died from rejection in this normally tolerogenic OLT (DA-PVG) combination. Injection of 1.5x10⁸ splenic leukocytes from naive DA rats into the irradiated DA donor rats 24 h before OLT restored the tolerogenic potential of the liver allografts. Immunofluorescence assay revealed an increased number of donor (DA) type cells in the PVG recipient bearing a repopulated DA liver, compared to the PVG recipient of an irradiated liver. These results suggest that passenger leukocytes reconstituted by splenic leukocytes have the capacity to protect liver allografts.