The Effect of Monthly Anti-CD25+ Treatment with Basiliximab on the Progression of Chronic Renal Dysfunction after Lung Transplantation.

BACKGROUND: Chronic renal dysfunction (CRD), as predominantly related to calcineurin-inhibitor (CNI) nephrotoxicity, is associated with increased morbidity and mortality after lung transplantation (LTx). Basiliximab (BSX), a recombinant chimeric monoclonal antibody against CD25+ on activated T-lymphocytes, although often employed as an "induction immunosuppression" after solid organ transplantation, may further allow for reduction in CNI exposure with monthly administration and amelioration of CRD. OBJECTIVE: To determine the effect of monthly anti-CD25+ treatment with basiliximab on the progression of chronic renal dysfunction after lung transplantation. METHODS: Post-LTx recipients with stages IIIB-V CRD were treated with monthly intravenous infusion of BSX 20 mg. They were analyzed for creatinine clearance at 1, 3, 6, and 12 months; rate of the change in the clearance (the slope of the regression line) and FEV1/month; de novo HLA class I or II DSA; and infectious events (IE). Tacrolimus (TAC) trough levels were concurrently targeted at 2-4 ng/mL during BSX therapy. The criteria for BSX discontinuation included acute lung allograft rejection, acute respiratory infection, and progression to end-stage renal disease (ESRD). RESULTS: 9 LTx recipients were treated with BSX for ≥6 months. The median time past after their LTx was 1853 (range: 75-7212) days; the mean±SD age was 64.3±11.3 years; the male:female ratio was 7:2. The baseline mean±SD creatinine clearance 1-3 months prior to BSX initiation was 22.8±5.14 mL/min/1.73 m2 (CI: 3.95) consistent with CRD stages-IIIB (2), IV (6), and V (1). Prior to BSX treatment, all 9 patients had established CLAD-obstructive-phenotype (BOS, n=4) and restrictive-phenotype (RAS, n=5). During the course of BSX treatment, the aggregate creatinine clearance mean slope increased by a mean±SD of 0.747±0.467 mL/min/1.72 m2/month (CI: 0.359), consistent with "stabilization" of renal function in 7 patients; deterioration occurred in 2 with transition to chronic hemodialysis. Spirometric stability in lung allograft function was observed in 5 patients with a mean±SD aggregate FEV1 slope of -1.49±1.08 mL/month (CI: 2.50). 3 deaths occurred due to the following conditions during BSX treatment-HFpEF/Sepsis + CLAD/Parainfluenza type 2 bronchiolitis + CLAD. 2 recipients developed "weak MFI" HLA class II DSA; no HLA class I DSA was detected during the treatment. CONCLUSION: Renal sparing therapy with monthly BSX infusion with concurrent reduction in CNI exposure (TAC = 2-4 ng/mL) for stages IIIB-V CRD was associated with stability in creatinine clearance in 78% of patients over a treatment course of 6-12 months. Pre-existing CLAD afflicting all patients and inherent variability in progression of chronic rejection, limits our assessment of BSX efficacy in this context. We detected an infrequent de novo HLA class II DSA during BSX therapy.

The Prognostic Importance of Bronchoalveolar Lavage Fluid CXCL9 During Minimal Acute Rejection on the Risk of Chronic Lung Allograft Dysfunction.

The clinical significance and treatment strategies for minimal acute rejection (grade A1), the most common form of acute rejection (AR), remain controversial. In this retrospective single-center cohort study of 441 lung transplant recipients, we formally evaluate the association between minimal AR and chronic lung allograft dysfunction (CLAD) and test a novel hypothesis using bronchoalveolar lavage (BAL) CXCL9 concentration during minimal AR as a biomarker of subsequent CLAD development. In univariable and multivariable models adjusted for all histopathologic injury patterns, minimal AR was not associated with CLAD development. However, minimal AR with elevated BAL CXCL9 concentrations markedly increased CLAD risk in a dose-response manner. Minimal AR with CXCL9 concentrations greater than the 25th, 50th, and 75th percentile had adjusted hazard ratios (HRs) for CLAD of 1.1 (95% confidence interval [CI] 0.8-1.6), 1.6 (95% CI 1.1-2.3), and 2.2 (95% CI 1.4-3.4), respectively. Thus we demonstrate the utility of BAL CXCL9 measurement as a prognostic biomarker that allows discrimination of recipients at increased risk of CLAD development after minimal AR. BAL CXCL9 measurement during transbronchial biopsies may provide clinically useful prognostic data and guide treatment decisions for this common form of AR, as a possible strategy to minimize CLAD development.

Impact of Allograft Injury Time of Onset on the Development of Chronic Lung Allograft Dysfunction After Lung Transplantation.

The impact of allograft injury time of onset on the risk of chronic lung allograft dysfunction (CLAD) remains unknown. We hypothesized that episodes of late-onset (≥6 months) allograft injury would produce an augmented CXCR3/ligand immune response, leading to increased CLAD. In a retrospective single-center study, 1894 transbronchial biopsy samples from 441 lung transplant recipients were reviewed for the presence of acute rejection (AR), lymphocytic bronchiolitis (LB), diffuse alveolar damage (DAD), and organizing pneumonia (OP). The association between the time of onset of each injury pattern and CLAD was assessed by using multivariable Cox models with time-dependent covariates. Bronchoalveolar lavage (BAL) CXCR3 ligand concentrations were compared between early- and late-onset injury patterns using linear mixed-effects models. Late-onset DAD and OP were strongly associated with CLAD: adjusted hazard ratio 2.8 (95% confidence interval 1.5-5.3) and 2.0 (1.1-3.4), respectively. The early-onset form of these injury patterns did not increase CLAD risk. Late-onset LB and acute rejection (AR) predicted CLAD in univariable models but lost significance after multivariable adjustment for late DAD and OP. AR was the only early-onset injury pattern associated with CLAD development. Elevated BAL CXCR3 ligand concentrations during late-onset allograft injury parallel the increase in CLAD risk and support our hypothesis that late allograft injuries result in a more profound CXCR3/ligand immune response.

The Role of TGF-ß in the Association Between Primary Graft Dysfunction and Bronchiolitis Obliterans Syndrome.

Primary graft dysfunction (PGD) is a possible risk factor for bronchiolitis obliterans syndrome (BOS) following lung transplantation; however, the mechanism for any such association is poorly understood. Based on the association of TGF-ß with acute and chronic inflammatory disorders, we hypothesized that it might play a role in the continuum between PGD and BOS. Thus, the association between PGD and BOS was assessed in a single-center cohort of lung transplant recipients. Bronchoalveolar lavage fluid concentrations of TGF-ß and procollagen collected within 24 h of transplantation were compared across the spectrum of PGD, and incorporated into Cox models of BOS. Immunohistochemistry localized expression of TGF-ß and its receptor in early lung biopsies posttransplant. We found an association between PGD and BOS in both bilateral and single lung recipients with a hazard ratio of 3.07 (95% CI 1.76-5.38) for the most severe form of PGD. TGF-ß and procollagen concentrations were elevated during PGD (p < 0.01), and associated with increased rates of BOS. Expression of TGF-ß and its receptor localized to allograft infiltrating mononuclear and stromal cells, and the airway epithelium. These findings validate the association between PGD and the subsequent development of BOS, and suggest that this association may be mediated by receptor/TGF-ß biology.

Staphylococcus via an interaction with the ELR+ CXC chemokine ENA-78 is associated with BOS.

Staphylococcus aureus is the most commonly isolated gram-positive bacterium after lung transplantation (LT) and has been associated with poor posttransplant outcomes, but its effect on bronchiolitis obliterans syndrome (BOS) and death in the context of the allograft inflammatory environment has not been studied. A three-state Cox semi-Markovian model was used to determine the influence of allograft S. aureus and the ELR+ CXC chemokines on the survival rates and cause-specific hazards for movement from lung transplant (State 1) to BOS (State 2), from transplant (State 1) to death (State 3), and from BOS (State 2) to death (State 3). Acute rejection, pseudomonas pneumonia, bronchoalveolar lavage fluid (BALF) CXCL5 and its interaction with S. aureus all increased the likelihood of transition from transplant to BOS. Transition to death from transplant was facilitated by pseudomonas infection and single lung transplant. Movement from BOS to death was affected by the interaction between aspergillus, pseudomonas and CXCL5, but not S. aureus. S. aureus isolation had state specific effects after LT and only in concert with elevated BALF CXCL5 concentrations did it augment the risk of BOS. Pseudomonas and elevated BALF concentrations of CXCL5 continued as significant risk factors for BOS and death after BOS in lung transplantation.

Selecting oversized donor cardiac allografts for patients with pulmonary hypertension may be unnecessary.

INTRODUCTION: There is a tendency to favor oversized donor hearts for heart transplant candidates affected by mild to moderate pulmonary hypertension (PHTN). We hypothesize that both undersized and oversized donor hearts fare equally well in this setting. METHODS: A total of 107 cases from 2003 to 2008 were retrospectively reviewed and subsequently divided into those receiving organs from undersized donors (group 1: donor weight/recipient weight ≤ 0.90, n = 37) and oversized donors (group 2: donor weight/recipient weight ≥ 1.2, n = 70). PHTN was identified in the perioperative period in those patients with systolic pulmonary artery pressure (SPAP) ≥ 40 mm Hg. Endpoints of mortality and hemodynamic data were investigated. RESULTS: Of 107 patients, 37 received undersized donor allografts, with a mean donor-to-recipient weight ratio of 0.8, and 70 received oversized donors allografts, with a mean donor-to-recipient ratio of 1.4. Perioperative PAH was diagnosed in 20 of the 37 (54%) patients from the undersized group (mean SPAP = 45.9 mm Hg) and 41 of 70 (59%) patients from the oversized group (mean SPAP = 46.5 mm Hg). There was no significant difference in right ventricular function at 1 week, 1 month, or 6 months. Left ventricular function was similar between both groups at 6 months (P = .22). The mean SPAP in the undersized group was 45.9, 33.4, 31.8, and 23.1 mm Hg at the perioperative, 1 week, 1 month, and 6 month time points, respectively. Corresponding mean SPAP for the oversized group was 46.5, 35.0, 29.4, and 26.1 mm Hg. The 1 month, 1 year, and 3 year survivals were similar in both groups. CONCLUSIONS: Oversized and undersized donor hearts fared equally well in the setting of mild to moderate perioperative PAH. This in addition to the propensity for resolution of pulmonary hypertension over time suggests that the current practice of favoring oversized donor hearts for patients with pre-transplantation PAH may be unwarranted.

Colonization with small conidia Aspergillus species is associated with bronchiolitis obliterans syndrome: a two-center validation study.

Aspergillus colonization after lung transplantation may increase the risk for bronchiolitis obliterans syndrome (BOS), a disease of small airways. We hypothesized that colonization with small conidia Aspergillus species would be associated with a greater risk of BOS, based upon an increased likelihood of deposition in small airways. We studied adult primary lung recipients from two large centers; 298 recipients at University of California, Los Angeles and 482 recipients at Duke University Medical Center. We grouped Aspergillus species by conidia diameter≤3.5 µm. We assessed the relationship of colonization with outcomes in Cox models. Pre-BOS colonization with small conidia Aspergillus species, but not large, was a risk factor for BOS (p=0.002, HR 1.44, 95% CI 1.14-1.82), along with acute rejection, single lung and Pseudomonas. Colonization with small conidia species also associated with risk of death (p=0.03, HR 1.30, 95% CI 1.03-1.64). Although other virulence traits besides conidia size may be important, we have demonstrated in two large independent cohorts that colonization with small conidia Aspergillus species increases the risk of BOS and death. Prospective evaluation of strategies to prevent Aspergillus colonization of small airways is warranted, with the goal of preserving lung allograft function as long as possible.

CXCR3 chemokine ligands during respiratory viral infections predict lung allograft dysfunction.

Community-acquired respiratory viruses (CARV) can accelerate the development of lung allograft dysfunction, but the immunologic mechanisms are poorly understood. The chemokine receptor CXCR3 and its chemokine ligands, CXCL9, CXCL10 and CXCL11 have roles in the immune response to viruses and in the pathogenesis of bronchiolitis obliterans syndrome, the predominant manifestation of chronic lung allograft rejection. We explored the impact of CARV infection on CXCR3/ligand biology and explored the use of CXCR3 chemokines as biomarkers for subsequent lung allograft dysfunction. Seventeen lung transplant recipients with CARV infection had bronchoalveolar lavage fluid (BALF) available for analysis. For comparison, we included 34 BALF specimens (2 for each CARV case) that were negative for infection and collected at a duration posttransplant similar to a CARV case. The concentration of each CXCR3 chemokine was increased during CARV infection. Among CARV infected patients, a high BALF concentration of either CXCL10 or CXCL11 was predictive of a greater decline in forced expiratory volume in 1 s, 6 months later. CXCR3 chemokine concentrations provide prognostic information and this may have important implications for the development of novel treatment strategies to modify outcomes after CARV infection.

Systemic sclerosis and bilateral lung transplantation: a single centre experience.

Lung involvement is the leading cause of death in systemic sclerosis (SSc), but lung transplantation (LT) for systemic disease remains controversial. Our objective was to comprehensively evaluate post-LT outcomes for SSc compared to idiopathic pulmonary fibrosis (IPF). We retrospectively evaluated bilateral LT recipients (LTRs) with SSc or IPF at our centre between January 1, 2003 and December 31, 2007. The primary end-point was all-cause mortality at 1 yr post-LT. Secondary end-points included assessments of acute rejection (AR), pulmonary function, infection and chronic rejection. 14 patients with SSc and 38 patients with IPF underwent LT. Apart from a younger SSc cohort (53.2 versus 58.8 yrs; p = 0.02), the two groups were well matched. 1-yr all-cause mortality was no different between SSc (6.6%) and IPF (13.1%) groups, after adjusting for age (p = 0.62). Rates of (AR) ≥2 were significantly increased for the SSc compared with the IPF group (hazard ratio (HR) 2.91; p = 0.007). Other end-points, including chronic rejection, infection and pulmonary function, showed no differences. SSc LTRs experience similar survival 1 yr post-LT when compared to IPF. AR rates may be significantly higher in the SSc group. Longer follow-up is necessary to determine the effects of gastrointestinal dysfunction and AR on late allograft function in SSc LTR.

Aspergillus colonization of the lung allograft is a risk factor for bronchiolitis obliterans syndrome.

Multiple infections have been linked with the development of bronchiolitis obliterans syndrome (BOS) post-lung transplantation. Lung allograft airway colonization by Aspergillus species is common among lung transplant recipients. We hypothesized that Aspergillus colonization may promote the development of BOS and may decrease survival post-lung transplantation. We reviewed all lung transplant recipients transplanted in our center between January 2000 and June 2006. Bronchoscopy was performed according to a surveillance protocol and when clinically indicated. Aspergillus colonization was defined as a positive culture from bronchoalveolar lavage or two sputum cultures positive for the same Aspergillus species, in the absence of invasive pulmonary Aspergillosis. We found that Aspergillus colonization was strongly associated with BOS and BOS related mortality in Cox regression analyses. Aspergillus colonization typically preceded the development of BOS by a median of 261 days (95% CI 87-520). Furthermore, in a multivariate Cox regression model, Aspergillus colonization was a distinct risk factor for BOS, independent of acute rejection. These data suggest a potential causative role for Aspergillus colonization in the development of BOS post-lung transplantation and raise the possibility that strategies aimed to prevent Aspergillus colonization may help delay or reduce the incidence of BOS.

Pulmonary hypertension associated with lung transplantation obliterative bronchiolitis and vascular remodeling of the allograft.

Pathologic obliterative bronchiolitis (OB)/Bronchiolitis obliterans syndrome (pathologic OB/BOS) is the major obstacle to long-term survival post-lung transplantation (LT). Our group has demonstrated that pulmonary hypertension (PH) complicates the course of chronic inflammatory lung diseases that have similarities to pathologic OB/BOS and that vascular remodeling of the bronchial circulation occurs during BOS. Consequently, we hypothesized that PH is associated with pathologic OB/BOS and may result from a vasculopathy of the allograft pulmonary circulation. We conducted a single-center, retrospective study and examined the presence of PH and vasculopathy in patients with pathologic OB/BOS. Fifty-two pathologic specimens post-LT were recovered from January 10, 1997 to January 5, 2007 and divided into two groups, those with and without pathologic OB/BOS.PH was defined as a mean pulmonary artery pressure (mPAP) > 25 mmHg by right heart catheterization (RHC) or right ventricular systolic pressure (RVSP) > or = 45 mmHg by transthoracic echocardiogram (TTE). PH was more prevalent in those LT recipients with pathologic OB/BOS (72% vs. 0%, p = 0.003). Furthermore, pulmonary arteriopathy and venopathy were more prevalent in patients with pathologic OB/BOS (84% vs. 4%, p < 0.0001, and 77% vs. 35%, p = 0.004, respectively). PH is common in LT recipients with pathologic OB/BOS and is associated with a vasculopathy of the allograft pulmonary circulation.

Altered levels of CC chemokines during pulmonary CMV predict BOS and mortality post-lung transplantation.

Pulmonary CMV infection (CMVI) and disease (CMVD) is associated with reduced long-term survival post-lung transplantation, however, the specific biologic mechanisms remain unclear. We have demonstrated a role of CC chemokines during lung allograft dysfunction. Based on these findings, we hypothesized that pulmonary CMV upregulates the expression of multiple CC chemokines that leads to allograft dysfunction and decreased long-term survival. We performed a nested case control study in lung transplant recipients to investigate alterations in CC chemokine biology during pulmonary CMV. Levels of CC chemokines were measured in bronchoalveolar lavage fluid (BALF) from recipients with CMVI (n = 33), CMVD (n = 6), and in healthy lung transplant controls (n = 33). We found a trend toward increased levels of MIP-1alpha/CCL3 during pulmonary CMVI. Levels of MCP-1/CCL2 and RANTES/CCL5 were significantly elevated during pulmonary CMV. Interestingly, elevated levels of CCL3 in BALF were protective with regards to survival. Importantly, elevated levels of CCL2 in BALF predicted the development of BOS, while elevated levels of CCL5 in BALF predicted an increase in mortality post-lung transplant. Altered levels of specific CC chemokines during pulmonary CMV are associated with future clinical outcomes. These results suggest a possible utility of BALF CC chemokines as biomarkers for guiding risk assessment during pulmonary CMV post-lung transplantation.

Role of CXCR3 and CCR5 in allograft rejection.

UNLABELLED: Chemokines are known to participate in allograft rejection by mediating leukocyte trafficking. Despite redundancy in chemokine family, several chemokine-chemokine receptor interactions have proven critical in alloimmune responses. We sought to determine the effect of combined blockade of CXCR3 and CCR5, two critical chemokine receptors, in acute rejection. METHODS: Heterotopic heart transplantation was performed using BALB/c to B6/129 mice deficient in CCR5. Following transplantation these mice were treated with goat anti-CXCR3 serum every other day. In the control group, BALB/c hearts were transplanted in wild type B6/129 recipients and treated with goat serum alone. No immunosuppression was given to either group. Recipient mice were then assessed daily for allograft function by abdominal palpation, and graft survival was confirmed by laparotomy. RESULTS: The donor hearts in the control group were rejected at 6 +/- 1 days posttransplantation. Combined blockade of CXCR3 and CCR5 prolonged allograft survival versus control; all allografts survived to 24 days. In addition, there was a decrease in graft infiltrating CD4 and CD8 lymphocytes in the experimental group at 24 days. CONCLUSION: Combined CXCR3 and CCR5 blockade is effective in prolonging allograft survival in a fully MHC mismatched murine model. Combined chemokine blockade holds promise in control of acute rejection in organ transplantation.

Cytoprotective gene HO-1 and chronic rejection in heart transplantation.

Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading cause of late death among heart transplant recipients. We hypothesized that induction of HO-1 by D4-F, an apoA-I mimetic peptide with potent antiinflammatory/antioxidant properties, attenuated CAV. We utilized a previously characterized murine model of CAV. B6.C-H2(bml2) hearts were heterotopically transplanted into C57BL/6 mice. In the control group, recipient mice were treated with 20 microg of saline daily. In experimental group I, mice were treated daily with 20 microg of D4-F. In experimental group II, mice were treated daily with 20 microg of D4-F daily, plus CuPP, which does not have any effect on HO-1 activity. In experimental group III, recipient mice were treated with 20 mug of D4-F daily, plus SnPP, which is a competitive inhibitor of HO-1. Donor hearts were harvested on day 24 after transplantation. The donor hearts in the control group developed severe intimal lesions. In experimental group I, treatment with D4-F was associated with upregulation of HO-1 and a marked reduction in intimal lesions, which was consistent in experimental group II. In experimental group III, inhibition of HO-1 was associated with partial restoration of intimal lesions. Induction of HO-1 by an apoA-1 mimetic peptide was effective to control CAV. This class of antiinflammatory peptides, which show an ability to induce HO-1, provides a novel strategy for the treatment of CAV.

Thoracic organ transplantation in the United States, 1995-2004.

This article reviews trends in thoracic organ transplantation based on OPTN/SRTR data from 1995 to 2004. The number of active waiting list patients for heart transplants continues to decline, primarily because there are fewer patients with coronary artery disease listed for transplantation. Waiting times for heart transplantation have decreased, and waiting list deaths also have declined, from 259 per 1000 patient-years at risk in 1995 to 156 in 2004. Fewer heart transplants were performed in 2004 than in 1995, but adjusted patient survival increased to 88% at 1 year and 73% at 5 years. Emphysema, idiopathic pulmonary fibrosis and cystic fibrosis were the most common indications among lung transplant recipients in 2004. Waiting time for lung transplantation decreased between 1999 and 2004. Waiting list mortality decreased to 134 per 1000 patient-years at risk in 2004. One-year survival following transplantation has improved significantly in the past decade. The number of combined heart-lung transplants performed in the United States remains low, with only 39 performed in 2004. Overall unadjusted survival, at 58% at 1 year and 40% at 5 years, is lower among heart-lung recipients than among either heart or lung recipients alone.

Inhaled nitric oxide for pulmonary hypertension after heart transplantation.

BACKGROUND: Recipient pulmonary hypertension due to chronic congestive heart failure is a major cause of right ventricular (RV) dysfunction after heart transplantation. We hypothesized that inhaled nitric oxide (NO), in the postoperative period, would a) selectively reduce pulmonary vascular resistance and improve RV hemodynamics and b) reduce the incidence of RV dysfunction compared with a matched historical group. METHODS: Sixteen consecutive adult heart transplant recipients with lowest mean pulmonary artery (PA) pressures >25 mmHg were prospectively enrolled. Inhaled NO at 20 parts per million (ppm) was initiated before termination of cardiopulmonary bypass (CPB). At 6 and 12 hours after CPB, NO was stopped for 15 minutes and systemic and pulmonary hemodynamics were measured. RV dysfunction was defined as central venous pressure >15 mmHg and consistent echocardiographic findings. The incidence of RV dysfunction and 30-day survival in this group was compared with a historical cohort of 16 patients matched for pulmonary hypertension. RESULTS: Discontinuation of NO for 15 minutes at 6 hours after transplantation resulted in a significant rise in mean PA pressure, pulmonary vascular resistance (PVR), and RV stroke work index. Systemic hemodynamics were not affected by NO therapy. One patient in the NO-treated group, compared with 6 patients in the historical cohort group, developed RV dysfunction (P< .05). The 30-day survival in the NO-treated group and the historical cohort group were 100% and 81%, respectively (P> .05). CONCLUSION: In heart transplant recipients with pulmonary hypertension, inhaled NO in the postoperative period selectively reduces PVR and enhances RV stroke work. Furthermore, NO reduces the incidence of RV dysfunction in this group of patients when compared with a historical cohort matched for pulmonary hypertension. Inhaled NO is a useful adjunct to the postoperative treatment protocol of heart transplant patients with pulmonary hypertension.

A prospective trial of inhaled nitric oxide in clinical lung transplantation.

BACKGROUND: Reperfusion injury (RI) is a major cause of mortality and morbidity among lung transplant recipients. We sought to determine if prophylactic administration of inhaled nitric oxide (NO) to lung transplant recipients at reperfusion would prevent RI. We also hypothesized that if prophylactic NO proves ineffective in preventing RI then it may improve pulmonary hemodynamics and gas exchange in the subset of patients who develop RI. METHODS: After informed consent, 28 consecutive, adult lung transplant recipients received NO at 20 ppm at reperfusion. NO was withdrawn for 15 min at 6 and 12 hr after reperfusion, and gas exchange and hemodynamics were measured. RESULTS: Five of the 28 lung transplant recipients (18%) developed RI. Withdrawal of NO for 15 min in this subset of patients resulted in a significant rise in mean pulmonary artery pressure and a reduction in oxygenation index. All five patients with RI were kept on inhaled NO until full functional recovery of the allograft and were then weaned from mechanical ventilation. None required extracorporeal membrane oxygenation support; the early mortality in this group was 20% (1/5). The remaining 23 patients without RI had uneventful early postoperative course and were weaned from NO and mechanical ventilation within 36 hr of transplantation. CONCLUSIONS: Prophylactic-inhaled NO does not prevent RI in human lung transplantation. However, inhaled NO, started at reperfusion, improves gas exchange and reduces pulmonary artery pressure in those patients who develop RI.

Rantes production during development of cardiac allograft vasculopathy.

BACKGROUND: RANTES (regulated on activation, normal T cell expressed and secreted) production has been shown to correlate with mononuclear cell recruitment and precede intimal thickening in cardiac allograft vasculopathy (CAV). However, the cells that produce RANTES in CAV are undefined. Therefore, in an MHC II-mismatched murine model of CAV, we sought to (1) define the cellular sources of RANTES and (2) determine the role of CD4+ lymphocytes in RANTES production during CAV development. METHODS: B6.CH-2bm12 strain donor hearts were transplanted heterotopically into wild-type (WT) or CD4 knockout (CD4KO) C57BL/6 mice (MHC II mismatch). No immunosuppression was used. Recipients were sacrificed at 7, 14, and 24 days. Intragraft RANTES gene expression and protein levels were determined with ribonuclease protection assay and ELISA, respectively. At days 7 and 24, RANTES production by graft-infiltrating cells was defined with intracellular RANTES staining and multicolor FACS analysis. Intimal thickening was quantitated morphometrically. In murine hearts and in six explanted human hearts with advanced CAV, RANTES was also localized immunohistochemically. RESULTS: NK, NKT, and gammadelta+ cells, in addition to CD4+, CD8+ lymphocytes, and CD11b+ macrophages, produced RANTES in early and late stages of CAV. RANTES-producing NK, NKT, and gammadelta+ cells tripled in number during CAV development; by day 24, NK and gammadelta+ cells each outnumbered CD4+ lymphocytes and CD11b+ macrophages. The presence of CD4+ lymphocytes was required for sustained RANTES production in allografts, which correlated with mononuclear cell recruitment and preceded intimal thickening. In murine and explanted human hearts with advanced CAV, RANTES immunolocalized with graft-infiltrating mononuclear cells and vessel wall cells. CONCLUSIONS: We present evidence that other cell types in addition to CD4+, CD8+ T lymphocytes, and CD11b+ macrophages contribute significantly to RANTES production in CAV. In this MHC II-mismatched murine model of CAV, sustained RANTES production requires CD4+ lymphocytes, correlates with mononuclear cell recruitment, and precedes intimal thickening. In experimental and human CAV, vessel wall cells may also produce RANTES. Interventions aimed at inhibiting RANTES production in CAV may need to target several types of cells, and neutralization of RANTES bioactivity may reduce mononuclear cell recruitment and CAV development.

CD8+ lymphocytes augment chronic rejection in a MHC class II mismatched model.

UNLABELLED: Chronic rejection, or cardiac allograft vasculopathy (CAV), remains the leading cause of late death in heart transplant recipients. The precise role and contributions of T lymphocyte subsets to CAV development remains unknown. METHODS: Donor hearts from B6.C-H2bm12 mice were transplanted into T lymphocyte subset knockout recipients and T lymphocyte-reconstituted nude recipients. No immunosuppression was used. Intimal proliferation was measured morphometrically. In vitro studies were performed to analyze the donor-specific activation status of recipient CD8+ lymphocytes by examining cellular proliferation, interleukin-2 secretion, and interleukin-2Ralpha expression. Intracellular cytokine staining assay was performed to determine both the profile and source of intragraft cytokines. RESULTS: Hearts transplanted into wild-type recipients developed severe CAV by 24 days. Intimal lesions were absent in the hearts that were transplanted into nude and CD4-/- knockout mice (containing CD8+ lymphocytes). In contrast, the donor hearts in CD8-/- knockout recipients (containing CD4+ lymphocytes) developed CAV, but significantly less than in wildtype. Adoptive transfer of T lymphocyte subset populations into nude recipients confirmed that CAV was absolutely contingent on CD4+ lymphocytes, and that CD8+ lymphocytes played an additive role in intimal lesion progression in the presence of CD4+ lymphocytes. Although CD8+ lymphocytes alone did not cause CAV in vivo, we demonstrated that MHC class II disparate alloantigens activated CD8+ lymphocytes both in vivo and in vitro. Finally, both CD4+ and CD8+ lymphocytes contributed to the intragraft IL-2 and IFN-gamma production. CONCLUSIONS: In this MHC class II mismatched murine model, CAV is a T lymphocyte dependent event, and absolutely contingent on the presence of CD4+ lymphocytes. Furthermore, CD8+ lymphocytes (1) are activated by MHC class II disparate antigens and (2) play a significant role in the progression of lesion development. Finally, both CD4+ and CD8+ lymphocytes contribute to CAV development via secretion of IFN-gamma, a known mediator of CAV in this model.