Bronchiolitis obliterans in single-lung transplant recipients

Parametric Response Mapping as an Imaging Biomarker in Lung Transplant Recipients

RATIONALE

The predominant cause of chronic lung allograft failure is small airway obstruction arising from bronchiolitis obliterans. However, clinical methodologies for evaluating presence and degree of small airway disease are lacking.

OBJECTIVES

To determine if parametric response mapping (PRM), a novel computed tomography voxel-wise methodology, can offer insight into chronic allograft failure phenotypes and provide prognostic information following spirometric decline.

METHODS

PRM-based computed tomography metrics quantifying functional small airways disease (PRM^fSAD) and parenchymal disease (PRM^PD) were compared between bilateral lung transplant recipients with irreversible spirometric decline and control subjects matched by time post-transplant (n = 22). PRM^fSAD at spirometric decline was evaluated as a prognostic marker for mortality in a cohort study via multivariable restricted mean models (n = 52).

MEASUREMENTS AND MAIN RESULTS

Patients presenting with an isolated decline in FEV₁ (FEV₁ First) had significantly higher PRM^fSAD than control subjects (28% vs. 15%; P = 0.005), whereas patients with concurrent decline in FEV₁ and FVC had significantly higher PRM^PD than control subjects (39% vs. 20%; P = 0.02). Over 8.3 years of follow-up, FEV₁ First patients with PRM^fSAD greater than or equal to 30% at spirometric decline lived on average 2.6 years less than those with PRM^fSAD less than 30% (P = 0.004). In this group, PRM^fSAD greater than or equal to 30% was the strongest predictor of survival in a multivariable model including bronchiolitis obliterans syndrome grade and baseline FEV_1% predicted (P = 0.04).

CONCLUSIONS

PRM is a novel imaging tool for lung transplant recipients presenting with spirometric decline. Quantifying underlying small airway obstruction via PRM^fSAD helps further stratify the risk of death in patients with diverse spirometric decline patterns.

Comparison of extracorporeal photopheresis and alemtuzumab for the treatment of chronic lung allograft dysfunction

BACKGROUND

Survival after lung transplantation is limited by chronic lung allograft dysfunction (CLAD). Immunomodulatory therapies such as extracorporeal photopheresis (ECP) and alemtuzumab (AL) have been described for refractory CLAD, but comparative outcomes are not well defined.

METHODS

We retrospectively reviewed spirometric values and clinical outcomes after therapy with ECP, AL, or no treatment (NT) in patients with CLAD who underwent transplant between January 2005 and December 2014. We used inverse probability-weighted regression adjustment (IPWRA) to adjust for potential confounders affecting treatment choice.

RESULTS

Of 267 patients, 31 received immunomodulatory therapies for CLAD, and 78 received NT. The slope of forced expiratory volume in 1 second (FEV₁) decline significantly improved after treatment with AL and with ECP compared with pre-treatment FEV₁ slope; however, there was no significant change in slope of forced vital capacity (FVC). Comparison with NT was limited because of clinical differences in treatment groups. After IPWRA, we found no significant difference in mean difference of FEV₁ slope (ml/month) when comparing treatment with NT, suggesting stabilization of lung function in the treatment group. We found no difference between the 2 immunomodulatory therapies 1, 3, and 6 months post-treatment (-49.9 [95% CI -581.8, +482.0], p = 0.85; +27.7 [95% CI -167.6, +223.0], p = 0.78; -9.6 [95% CI -167.5, +148.2], p = 0.91). We found no difference in mean FVC slope or differences between ECP and AL in infection rates or survival after treatment.

CONCLUSIONS

Immunomodulatory therapy for CLAD with ECP or AL was associated with a significant change in FEV₁ slope post-treatment compared with pre-treatment slope, with minimal effect on FVC. There was no difference between the 2 therapies in their effect on pulmonary function.

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.

Longitudinal Forced Vital Capacity Monitoring as a Prognostic Adjunct after Lung Transplantation

RATIONALE

After lung transplantation, spirometric values are routinely followed to assess graft function. FEV1 is used to characterize chronic allograft dysfunction, whereas the course of FVC change has been less acknowledged and rarely used.

OBJECTIVES

To better understand the temporal relationship and prognostic ability of FEV1 and FVC decline after lung transplantation.

METHODS

Serial FEV1 and FVC values were studied among 205 bilateral lung transplant recipients. Different decline patterns were characterized and evaluated for prognostic value via restricted mean modeling of mortality and times to other pertinent events.

MEASUREMENTS AND MAIN RESULTS

Baseline FEV1 was achieved earlier than baseline FVC (median, 296 vs. 378 d; P < 0.0001). Decline in FEV1 or FVC from their respective post-transplant baselines occurred in 85 patients (41%). Fifty-nine of 85 (69%) had an isolated FEV1 decline, with 80% later meeting the FVC decline criterion. This subsequent FVC decline was associated with worsening FEV1 and lower median survival. Twenty-five of 85 patients (29%) demonstrated concurrent FEV1 and FVC decline. Patients with concurrent decline had higher 1- and 5-year mortality rates (1-yr, 53% vs. 18%, P < 0.0001; 5-yr, 61% vs. 48%, P = 0.001). These patients were more likely to have rapid-onset of spirometry decline (P = 0.05) and lower FEV1% predicted (P = 0.04) at presentation.

CONCLUSIONS

FVC decline from its post-transplant baseline provides valuable prognostic information. Concurrent FEV1 and FVC decline identifies patients with fulminant, rapid deterioration and is the strongest clinical predictor of poor survival. Subsequent FVC decline in patients with an initial isolated FEV1 decline identifies disease progression and portends poor prognosis.

An international ISHLT/ATS/ERS clinical practice guideline: diagnosis and management of bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is a major complication of lung transplantation that is associated with poor survival. The International Society for Heart and Lung Transplantation, American Thoracic Society, and European Respiratory Society convened a committee of international experts to describe and/or provide recommendations for 1) the definition of BOS, 2) the risk factors for developing BOS, 3) the diagnosis of BOS, and 4) the management and prevention of BOS. A pragmatic evidence synthesis was performed to identify all unique citations related to BOS published from 1980 through to March, 2013. The expert committee discussed the available research evidence upon which the updated definition of BOS, identified risk factors and recommendations are based. The committee followed the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) approach to develop specific clinical recommendations. The term BOS should be used to describe a delayed allograft dysfunction with persistent decline in forced expiratory volume in 1 s that is not caused by other known and potentially reversible causes of post-transplant loss of lung function. The committee formulated specific recommendations about the use of systemic corticosteroids, cyclosporine, tacrolimus, azithromycin and about re-transplantation in patients with suspected and confirmed BOS. The diagnosis of BOS requires the careful exclusion of other post-transplant complications that can cause delayed lung allograft dysfunction, and several risk factors have been identified that have a significant association with the onset of BOS. Currently available therapies have not been proven to result in significant benefit in the prevention or treatment of BOS. Adequately designed and executed randomised controlled trials that properly measure and report all patient-important outcomes are needed to identify optimal therapies for established BOS and effective strategies for its prevention.

Survival after bronchiolitis obliterans syndrome among bilateral lung transplant recipients

RATIONALE

Despite the importance of bronchiolitis obliterans syndrome (BOS) in lung transplantation, little is known regarding the factors that influence survival after the onset of this condition, particularly among bilateral transplant recipients.

OBJECTIVES

To identify factors that influence survival after the onset of BOS among bilateral lung transplant recipients.

METHODS

The effect of demographic or clinical factors, occurring before BOS, upon survival after the onset of BOS was studied in 95 bilateral lung transplant recipient using Cox proportional hazards models.

MEASUREMENTS AND MAIN RESULTS

Although many factors, including prior acute rejection or rejection treatments, were not associated with survival after BOS, BOS onset within 2 years of transplantation (early-onset BOS), or BOS onset grade of 2 or 3 (high-grade onset) were predictive of significantly worse survival (early onset P = 0.04; hazard ratio, 1.84; 95% confidence interval, 1.03-3.29; high-grade onset P = 0.003; hazard ratio, 2.40; 95% confidence interval, 1.34-4.32). The effects of both early onset and high-grade onset on survival persisted in multivariable analysis and after adjustment for concurrent treatments. Results suggested an interaction might exist between early onset and high-grade onset. In particular, high-grade onset of BOS, regardless of its timing after transplant, is associated with a very poor prognosis.

CONCLUSIONS

The course of BOS after bilateral lung transplantation is variable. Distinct patterns of survival after BOS are evident and related to timing or severity of onset. Further characterization of these subgroups should provide a more rational basis from which to design, stratify, and assess response in future BOS treatment trials.

Azithromycin is associated with increased survival in lung transplant recipients with bronchiolitis obliterans syndrome

BACKGROUND

Previous studies have suggested that azithromycin improves lung function in lung transplant recipients with bronchiolitis obliterans syndrome (BOS). However, these studies did not include a non-treated BOS control cohort or perform survival analysis. This study was undertaken to estimate the effect of azithromycin treatment on survival in lung transplant recipients with BOS.

METHODS

We conducted a retrospective cohort study of consecutive lung transplant recipients who developed BOS between 1999 and 2007. An association between azithromycin treatment and death was assessed using univariate and multivariate time-dependent Cox regression analysis.

RESULTS

Of the 178 recipients who developed BOS in our study, 78 did so after 2003 and were treated with azithromycin. The azithromycin-treated and untreated cohorts had similar baseline characteristics. Univariate analysis demonstrated that azithromycin treatment was associated with a survival advantage and this beneficial treatment effect was more pronounced when treatment was initiated during BOS Stage 1. Multivariate analysis demonstrated azithromycin treatment during BOS Stage 1 (adjusted hazard ratio = 0.23, p = 0.01) and absolute forced expiratory volume in 1 second (FEV(1)) at the time of BOS Stage 1 (adjusted hazard ratio = 0.52, p = 0.003) were both associated with a decreased risk of death.

CONCLUSIONS

In lung transplant recipients with BOS Stage 1, azithromycin treatment initiated before BOS Stage 2 was independently associated with a significant reduction in the risk of death. This finding supports the need for a randomized, controlled trial to confirm the impact of azithromycin on survival in lung transplant recipients.

Saber-sheath trachea in a patient with bronchiolitis obliterans syndrome after lung transplantation

Chronic rejection remains a major source of morbidity and mortality following lung transplantation. The clinical characteristics of chronic rejection involves bronchiolitis obliterans syndrome (BOS), which leads to progressive airway obstruction. Changes in intrathoracic tracheal dimensions and shape are commonly present in the setting of airway obstruction, leading to the narrowing of the intrathoracic trachea in the coronal plane with anteroposterior lengthening characteristic of the saber-sheath trachea deformity. We present a 64-year-old man who underwent left lung transplantation for idiopathic pulmonary fibrosis who later developed saber-sheath trachea as a result of chronic airway obstruction due to BOS.

CD28 down-regulation on CD4 T cells is a marker for graft dysfunction in lung transplant recipients

RATIONALE

Repeated antigen-driven proliferations cause CD28 on T cells to down-regulate. We hypothesized that alloantigen-induced proliferations could cause CD28 down-regulation in lung transplant recipients.

OBJECTIVES

To ascertain if CD28 down-regulation on CD4 T cells associated with manifestations of allograft dysfunction in lung transplant recipients.

METHODS

Peripheral blood CD4 T cells from 65 recipients were analyzed by flow cytometry, cytokine multiplex and proliferative assays, and correlated with clinical events.

MEASUREMENTS AND MAIN RESULTS

Findings that CD28 was present on less than 90% of total CD4 T cells were predominantly seen among the recipients with bronchiolitis obliterans syndrome (specificity = 88%). Perforin and granzyme B were produced by >50% of the CD4(+)CD28(null) cells, but less than 6% of autologous CD4(+)CD28(+) cells (P < 0.006). CD4(+)CD28(null) cells also had increased productions of proinflammatory cytokines, but less frequently expressed regulatory T-cell marker FoxP3 (2.1 +/- 1.3%), compared with autologous CD4(+)CD28(+) (9.5 +/- 1.4; P = 0.01). Cyclosporine A (100 ng/ml) inhibited proliferation of CD4(+)CD28(null) cells by 33 +/- 11% versus 68 +/- 12% inhibition of CD4(+)CD28(+) (P = 0.025). FEV(1) fell 6 months later (0.35 +/- 0.04 L) in recipients with CD4(+)CD28(+)/CD4(total) less than 90% (CD28% Low) compared with 0.08 +/- 0.08 L among CD4(+)CD28(+)/CD4(total) (CD28% High) greater than 90% (CD28% High) recipients (P = 0.013). Two-year freedom from death or retransplantation in CD28% Low recipients was 32 +/- 10% versus 78 +/- 6% among the CD28% High subjects (P < 0.0001).

CONCLUSIONS

CD28 down-regulation on CD4 cells is associated with bronchiolitis obliterans syndrome and poor outcomes in lung transplantation recipients. CD4(+)CD28(null) cells have unusual, potentially pathogenic characteristics, and could be important in the progression of allograft dysfunction. These findings may illuminate a novel paradigm of transplantation immunopathogenesis, and suggest that CD28 measurements could identify recipients at risk for clinical deteriorations.

Course of Illness after the Onset of Chronic Rejection in Lung Transplant Recipients

Background Despite the overall negative impact of chronic rejection on quality of life and survival after lung transplant, the specific clinical indicators of deterioration have not been identified.

Objectives To describe the course of illness after the onset of chronic rejection, including demographic and transplant variables, morbidity, mortality, health resource utilization, and end-of-life care, and to identify clinical indicators of deterioration in health and limited survival after the onset of chronic rejection.

Methods The medical records of 311 recipients of lung transplants between 1998 and 2004 were reviewed retrospectively to identify 60 recipients who experienced chronic rejection.

Results Median survival after chronic rejection was 31.34 months. Time to rejection (mean, 26.05 months; SD, 16.85) was significantly correlated with overall survival without need of a retransplant (r = 0.64; P &lt; .001). The earlier the onset of chronic rejection or the need for oxygen at home, the shorter was the period of survival after chronic rejection and the more frequent were hospital and intensive care unit admissions and prolonged stays. Of the 26 recipients who died, 65% died at the transplant center, and all but 1 died in the intensive care unit; 3 died after multiple attempts of cardiopulmonary resuscitation; life support was ultimately withdrawn in 69%.

Conclusions Lung transplant recipients who experience chronic graft rejection have high rates of morbidity, mortality, and health resource utilization; however, the course of illness after chronic rejection is highly variable.

Obliterative Bronchiolitis

Obliterative bronchiolitis (OB) is a condition characterized by inflammation and fibrosis of the bronchiolar walls resulting in narrowing or obliteration of the bronchiolar lumen. The most common causes are childhood lower respiratory tract infection, hematopoietic stem cell or lung and heart-lung transplantation, and toxic fume inhalation. The most frequent clinical manifestations are progressive dyspnea and dry cough. Pulmonary function tests demonstrate airflow obstruction and air trapping. Radiographic manifestations include reduction of the peripheral vascular markings, increased lung lucency, and overinflation. The chest radiograph, however, is often normal. High-resolution CT is currently the imaging modality of choice in the assessment of patients with suspected or proven OB. The characteristic findings on high-resolution CT consist of areas of decreased attenuation and vascularity (mosaic perfusion pattern) on inspiratory scans and air trapping on expiratory scans. Other CT findings of OB include bronchiectasis and bronchiolectasis, bronchial wall thickening, small centrilobular nodules, and three-in-bud opacities. Recent studies suggest that hyperpolarized ³He-enhanced magnetic resonance imaging may allow earlier recognition of obstructive airway disease and therefore may be useful in the diagnosis and follow-up of patients with OB.

Course of FEV(1) after onset of bronchiolitis obliterans syndrome in lung transplant recipients

RATIONALE

Bronchiolitis obliterans syndrome (BOS), defined by loss of lung function, develops in the majority of lung transplant recipients. However, there is a paucity of information on the subsequent course of lung function in these patients.

OBJECTIVES

To characterize the course of FEV(1) over time after development of BOS and to determine the predictors that influence the rate of functional decline of FEV(1).

METHODS

FEV(1)% predicted (FEV(1)%pred) trajectories were studied in 111 lung transplant recipients with BOS by multivariate, linear, mixed-effects statistical models.

MEASUREMENTS AND MAIN RESULTS

FEV(1)%pred varied over time after BOS onset, with the steepest decline typically seen in the first 6 months (12% decline; p < 0.0001). Bilateral lung transplant recipients had significantly higher FEV(1)%pred at BOS diagnosis (71 vs. 47%; p < 0.0001) and at 24 months after BOS onset (58 vs. 41%; p = 0.0001). Female gender and pretransplant diagnosis of idiopathic pulmonary fibrosis were associated with a steeper decline in FEV(1)%pred in the first 6 months after BOS diagnosis (p = 0.02 and 0.04, respectively). A fall in FEV(1) greater than 20% in the 6 months preceding BOS (termed "rapid onset") was associated with shorter time to BOS onset (p = 0.01), lower FEV(1)%pred at BOS onset (p < 0.0001), steeper decline in the first 6 months (p = 0.03), and lower FEV(1)%pred at 2 years after onset (p = 0.0002).

CONCLUSIONS

Rapid onset of BOS, female gender, pretransplant diagnosis of idiopathic pulmonary fibrosis, and single-lung transplantation are associated with worse pulmonary function after BOS onset.

Distal esophagitis in patients with mustard-gas induced chronic cough

Although confounded by some factors such as medications or surgical complications, the relationship between esophageal pathology and pulmonary disorders has been the subject of many studies. The present study sought to investigate the said relationship in patients inflicted by respiratory disorders induced by mustard gas (MG). A case group of patients complaining of respiratory complications and chronic coughs following MG exposure, and a control group of patients with chronic coughs but without a history of MG exposure were studied. All the case and control subjects had symptoms of gastro-esophageal reflux disease. Chest high resolution tomography (HRCT) was performed to evaluate the existence of pulmonary disorders. Endoscopy and histological studies were carried out to determine the severity of esophagitis in both groups presenting with gastroesophageal reflux. Ninety male patients, who had met our criteria, along with 40 male control cases underwent the diagnostic procedures. The frequency of endoscopic esophagitis findings in the chemically exposed group was significantly higher than that in the control group (70.0%vs. 42.5%). A pathological evaluation revealed that the frequency of esophagitis in the cases was more than that in the controls (32.3%vs. 14.2%). Chest HRCT evaluation demonstrated that half the case group had more than 25% air trapping in expiratory films, mostly compatible with bronchiolitis obliterans (BO). In addition, they were suffering from asthma, chronic bronchitis and bronchiectasis. Bronchiolitis obliterans, along with other lung disorders, can be considered as contributors in the pathogenesis of esophagitis in MG exposed patients.

Recovery of Chronic Renal Impairment With Sirolimus After Lung Transplantation

BACKGROUND

Standard immunosuppression after lung transplantation includes calcineurin inhibitors, azathioprine, and steroids. Calcineurin inhibitor administration is associated with an increased renal impairment. Sirolimus shows no renal toxicity and could be used in selected patients.

METHODS

We have prospectively administered sirolimus as an alternative to calcineurin inhibitors in 15 lung transplantation recipients with persistent drug nephrotoxicity. Eight patients had also bronchiolitis obliterans syndrome. The mean serum creatinine and azotemia were 2.7 +/- 1.1 mg/dL and 111 +/- 39 mg/dL. After starting sirolimus, azathioprine was reduced to 50%-25% of baseline, calcineurin inhibitors were gradually reduced and eventually stopped, and steroids were maintained stable. Patients started sirolimus with 2 to 5 mg/d orally; adjustments were made according to trough levels (4 to 12 ng/mL for combined sirolimus + calcineurin inhibitors; 12 to 20 ng/mL as monotherapy), toxicity, and perceived efficacy. Patients were monitored for renal and graft function and clinical status.

RESULTS

A significant creatinine decrease was observed after 6 months of treatment (p < 0.02); azotemia decreased after 1 month and remained stable (p < 0.01). Pulmonary function tests did not show any significant modification from before sirolimus baseline in patients without bronchiolitis obliterans syndrome. There were eight infectious complications and 10 episodes of toxicity (4 dermatitis, 2 epistaxis, 1 headache, 1 diarrhea, 1 nausea, 1 laryngeal cancer). Moderate leukocytopenia (n = 3) and hypertriglyceridemia (n = 6) responded to dose reduction. One patient was lost to follow-up. Three patients died of complications related to bronchiolitis obliterans. One patient underwent transplantation again.

CONCLUSIONS

Sirolimus administration allows amelioration of renal function with a relatively low morbidity and is useful for chronic renal impairment rescue after lung transplantation.

Bronchiolitis obliterans

Bronchiolitis obliterans (BO) is a disease of small airways that results in progressive dyspnea and airflow limitation. It is a common sequela of bone marrow, lung, and heart-lung transplantation, but can also occur as a complication of certain pulmonary infections, adverse drug reaction, toxic inhalation, and autoimmune disorders. Non-transplant-related BO is rare and can mimic asthma and chronic obstructive pulmonary disease (COPD). In transplant-related BO, the diagnosis can be suggested by obstructive changes in serial pulmonary function testings, while open lung biopsy is usually required in non-transplant cases. High-resolution computerized tomography (HRCT) is also a helpful tool to diagnose and assess the severity of BO. The treatment of BO, regarding of the cause, is usually disappointing. Systemic corticosteroid immunosuppression and retransplantation have been described with variable success.

Bronchiolitis obliterans

PURPOSE OF REVIEW

Bronchiolitis obliterans (BO) occurs in both post-lung transplant and nontransplant-related individuals, and is characterized by mainly irreversible airflow obstruction that is often ultimately progressive.

RECENT FINDINGS

While post-lung transplant BO is a major cause of lung allograft dysfunction, and hence is better characterized than nontransplant-related BO, it is likely that many similarities in pathogenesis and treatment apply to both categories.

SUMMARY

Optimal management for BO remains to be established, and the role of retransplantation in this disease requires further consensus. Minimization of risk factors for BO and earlier detection in the form of methacholine challenge testing and HRCT scans of the chest amongst other forms of detection, may help in the stabilization and possible resolution of early BO.

Bronchiolitis obliterans syndrome: utility of the new guidelines in single lung transplant recipients

BACKGROUND

Bronchiolitis obliterans syndrome is defined by a >20% decrease from baseline in the forced expiratory volume in 1 second (FEV(1)). Recently, a consensus panel under the auspices of the International Society for Heart and Lung Transplantation proposed a new stage, designated "potential BOS" or BOS 0-p. This study sought to validate retrospectively this new stage in a cohort of single-lung transplant recipients.

METHODS

A retrospective analysis of serial pulmonary function tests in 43 single-lung transplant recipients was performed. Baseline FEV(1) and midflow rate (FEF(25-75%)) were determined and compared with the most recent set of pulmonary function tests in clinically stable patients.

RESULTS

The sensitivity of the FEF(25-75%) at <or=75% of baseline for subsequently detecting BOS Stage 1 was 80%, with a specificity of 82.6%. For the patients with idiopathic pulmonary fibrosis, the sensitivity was 62.5% and the specificity was 100.0%, whereas in the patients with chronic obstructive lung disease, the sensitivity was 91.7% and the specificity was 69.2%. Different cutoff points for the FEF(25-75%) also were tested and are shown in receiver operator curves. Likelihood ratios for the different cutoff points also were calculated. Five of 9 (55.6%) patients qualified for BOS 0-p using the FEV(1) parameter (FEV(1) of 81-90% of baseline) alone.

CONCLUSION

The FEF(25-75%) seems to be a useful criterion for predicting BOS development in single-lung transplant recipients. The FEF(25-75%) might best be used with likelihood ratios for different values rather than for 1 defined cutoff point of or=75% of baseline. The value of the second criterion that constitutes BOS 0-p (FEV(1), 81-90%of baseline) remains uncertain.

Bronchiolitis obliterans syndrome in lung transplant recipients: correlation of computed tomography findings with bronchiolitis obliterans syndrome stage

The purpose of this study was to correlate the extent of computed tomographic (CT) findings with the severity of respiratory dysfunction in lung transplant recipients with bronchiolitis obliterans syndrome (BOS). Eighty-nine conventional and 61 thin-section CT scans performed in 44 transplant recipients (17 bilateral, 27 single) with BOS were reviewed for mosaic attenuation, degree of bronchial dilation, bronchial thickening, central and peripheral bronchiectasis, mucus plugging, and air trapping. Findings on conventional and thin-section CT scans were correlated with BOS stage for bilateral and single-lung transplant recipients. In bilateral-lung recipients, a significant correlation existed, although weak, between BOS stage and findings of degree of bronchial dilation (P < 0.01), bronchial wall thickening (P = 0.01), peripheral bronchiectasis (P = 0.01), and mosaic attenuation (P = 0.01) on conventional CT; and bronchial wall thickening (P = 0.01) and mosaic attenuation (P = 0.03) on thin-section CT. In single-lung recipients, BOS stage correlated only with the finding of central bronchiectasis (P = 0.02) on conventional CT scans. No correlation was found between the extent of air trapping and BOS stage in either single- or bilateral-lung transplant recipients. CT findings are relatively poor indices of airflow obstruction in lung transplant recipients with BOS, particularly in those with single-lung transplants for emphysema.

Early experience with sirolimus in lung transplant recipients with chronic allograft rejection

BACKGROUND

Chronic lung allograft rejection, commonly manifest as obliterative bronchiolitis (OB/BOS), hinders long-term survival after lung transplantation (LT). OB/BOS is traditionally treated with augmented immunosuppression and results in short-term stabilization in pulmonary function for most patients. However, peribronchiolar fibroproliferation and airway obstruction usually recur despite initial improvements seen with increases in immunosuppression. In this observational, uncontrolled study, the effect of sirolimus, a novel immunosuppressant with anti-proliferative activity, was assessed in LT patients with OB/BOS.

METHODS

Between June 1999 to November 2000, LT recipients with newly diagnosed or progressive OB/BOS received sirolimus in combination with a calcineurin inhibitor (CI) and prednisone. Pulmonary function, laboratory data and adverse effects were monitored for the first 24 weeks of therapy.

RESULTS

Sirolimus was utilized in 12 LT recipients with OB/BOS. After drug initiation, 58% of patients required a reduction in CI dose to maintain appropriate CI trough concentrations. Despite CI dose reduction, serum creatinine rose in 75% of patients. Unexpected adverse effects included anemia of chronic disease (100%), edema (50%) and malignancy (17%). For the group, the rate of change in FEV(1) and FEF(25%-75%) was unchanged with sirolimus, but individual responses varied.

CONCLUSIONS

For the group, the decline in pulmonary function was not affected by the addition of sirolimus. However, among individuals with rapidly declining pulmonary mechanics, sirolimus resulted in stabilization or improvement in pulmonary function. Significant adverse effects resulted from combination sirolimus plus CI therapy. Until optimal dosing strategies and a more complete adverse effect profile are established, combination therapy should be utilized cautiously in these patients.

Growth factor upregulation during obliterative bronchiolitis in the mouse model

Obliterative bronchiolitis (OB), or chronic allograft rejection, is a major cause of morbidity and mortality after lung transplantation. The goal of these experiments was to determine whether several important growth factors were upregulated during OB in the mouse heterotopic trachea model. Isografts (BALB/c into BALB/c) and allografts (BALB/c into C57BL/6) were implanted in three sets of cyclosporine-treated animals and were harvested from 2 to 10 weeks. Ribonucleic acid was isolated using the cesium chloride-guanidine method and was reverse transcribed and semiquantitated with the polymerase chain reaction using specific primers for platelet-derived growth factor (PDGF)-A and PDGF-B chains, fibroblast growth factor (FGF) isoforms 1 and 2, transforming growth factor-beta, tumor necrosis factor-alpha (TNF-alpha), edothelin-1, (prepro) epidermal growth factor, insulin-like growth factor-1, and beta-actin as a control. Transforming growth factor-beta, TNF-alpha, endothelin-1, and insulin-like growth factor-1 expression were increased 1.5-fold to 5.0-fold (p < or = 0.04 for each) in the allografts compared with the isografts at Weeks 2 through 6. Significantly increased expression of FGF-1, FGF-2, and PDGF-B was noted in the allografts at 4 weeks (p < 0.05 for each), which reversed at 6 and 10 weeks. No differences were found with the PDGF-A chain. The isografts expressed more epidermal growth factor than allografts (p < 0.001). Treatment with a TNF-alpha-soluble receptor (human TNFR:Fc) significantly reduced epithelial injury (p = 0.01) and lumenal obstruction (p = 0.037) in this model. We conclude that increased expression of a large number of growth factors occurs during OB in this model. Growth factor blockade (in particular with regard to TNF-alpha) may be useful in ameliorating OB in this model.

Bronchiolitis obliterans syndrome after single-lung transplantation: impact of time to onset on functional pattern and survival

INTRODUCTION

Among risk factors for the progression of bronchiolitis obliterans syndrome (BOS) after lung transplantation (LT), the influence of time to BOS onset is not known. The aim of the study was to assess if BOS occurring earlier after LT is associated with worse functional prognosis and worse graft survival.

METHOD

We retrospectively compared functional outcome and survival of all single-LT (SLT) recipients who had BOS develop during follow-up in our center according to time to onset of BOS (< 3 years or > or = 3 years after transplantation).

RESULTS

Among the 29 SLT recipients with BOS identified during the study period, 20 patients had early-onset BOS and 9 patients had late-onset BOS. The mean decline of FEV(1) over time during the first 9 months in patients with early-onset BOS was significantly greater than in patients with of late-onset BOS (p = 0.04). At last follow-up, patients with early-onset BOS had a lower mean FEV(1) value (25% vs 39% of predicted, p = 0.004), a lower mean PaO(2) value (54 mm Hg vs 73 mm Hg, p = 0.0005), a lower 6-min walk test distance (241 m vs 414 m, p = 0.001), a higher Medical Research Council index value (3.6 vs 1.6, p = 0.0001), and a higher percentage of oxygen dependency (90% vs 11%, p = 0.001) compared with patients with late-onset BOS. In addition, graft survival of patients with early-onset BOS was significantly lower than that of patients with late-onset BOS (log-rank test, p = 0.04). There were 18 of 20 graft failures (90%) in the early-onset BOS group, directly attributable to BOS in all cases (deaths [n = 10] or retransplantation [n = 8]). In the late-onset BOS group, graft failure occurred in four of nine patients due to death from extrapulmonary causes in three of four cases. The median duration of follow-up after occurrence of BOS was not statistically different between patients with early-onset BOS and patients with late-onset BOS (31 +/- 28 months and 37 +/- 26 months, respectively; p = not significant).

CONCLUSION

The subgroup of patients who had BOS develop > or = 3 years after SLT are less likely to have worrisome functional impairment develop in long-term follow-up. Considering the balance between the advantages and risks, enhancement of immunosuppression should be regarded with more caution in this subgroup than in patients with early-onset BOS.

Dynamic ventilation (3)He-magnetic resonance imaging with lung motion correction: gas flow distribution analysis

RATIONALE AND OBJECTIVES

Software was developed to correct for lung motion to improve the description of hyperpolarized (3)He gas distribution in the lung.

METHODS

Five volunteers were studied by dynamic ventilation (3)He-MRI using an ultrafast FLASH 2D sequence with a temporal resolution of 128 milliseconds. Signal kinetics were evaluated in the trachea and seven parenchymal Regions of Interest. Reference ranges for healthy subjects were defined for motion-corrected and uncorrected images.

RESULTS

Motion correction was successfully performed. Reference ranges were 0.11-1.21 seconds for tracheal transit time, 0-0.02 seconds for trachea-alveolar interval, 0.22-0.62 seconds for alveolar rise time and 0-76.6 arbitrary units for alveolar amplitude for motion corrected images, and 0-1.09 seconds, 0-0.11 seconds, 0.26-0.85 seconds, 46.4-99.8 arbitrary units for uncorrected images.

CONCLUSIONS

Evaluation of (3)He-distribution in the lung using motion correction of dynamic (3)He-ventilation imaging is feasible and gives more narrow reference ranges.

Early bronchiolitis obliterans following lung transplantation: accuracy of expiratory thin-section CT for diagnosis

PURPOSE

To evaluate the accuracy of thin-section computed tomography (CT) with expiratory scans in diagnosing early bronchiolitis obliterans after lung transplantation.

MATERIALS AND METHODS

Thin-section CT scans were reviewed by two observers blinded to the diagnoses in seven consecutive lung transplant recipients with histopathologically proved bronchiolitis obliterans (group A) and 21 with normal biopsy findings (group B). All patients had normal biopsy and stable pulmonary function test (PFT) results 2-36 weeks prior to CT. Patients with normal biopsy results were placed into subgroups based on abnormal (group B1) or stable (group B2) PFT results. Air-trapping extent on expiratory scans was scored on a 24-point scale.

RESULTS

The mean air-trapping score in group A (6.6) was not significantly different from that in group B (4.5, P =. 17). The air-trapping score was significantly higher in groups A and B1 than in group B2 (6.2 and 2.6, respectively; P =.03). The frequency of an air-trapping score of 3 or more in groups A and B1 was significantly higher than that in group B2 (P =.03). By using a score of 3 or more to indicate air trapping, the sensitivity of expiratory CT was 74%, specificity was 67%, and accuracy was 71%.

CONCLUSION

Thin-section CT, including expiratory scans, is of limited accuracy in diagnosing early bronchiolitis obliterans after lung transplantation.

Tests of airway function in detecting and monitoring treatment of obliterative bronchiolitis after lung transplantation

BACKGROUND

This study evaluated different tests of airway function in detection of obliterative bronchiolitis. It included analysis of spirogram within the time domain in patients with and without obliterative bronchiolitis (OB) after heart lung and lung transplantation. The purpose of this analysis is to evaluate which tests are of greatest value for early recognition of OB.

METHODS

The coefficient of variation of different airway function tests was calculated in 13 patients who had no evidence of OB and 12 patients who developed OB post-transplantation. In the patients with OB the effect of treatment with total lymphoid irradiation (TLI) was investigated by comparing the rate of change of lung function before and after TLI. Several lung function tests were used.

RESULTS

The measurements that showed the least variation were FEV(1), FVC, PEF, FEV(1)/FVC ratio and the Moment Ratio, while those which became abnormal earlier were FEV(1), FEV(1)/FVC, MEF(50), and the first moment. Additionally, the tests that became abnormal in a higher proportion of patients were MMEF, MEF(50), MEF(75), and the first moment.

CONCLUSIONS

The results o thi support the use of simple spirometric indices for the detection of OB. In the patients with OB the rates of decline of lung function were significantly attenuated by treatment with TLI as determined by several different tests.

KEYWORDS

obliterative bronchiolitis, lung transplantation, moments analysis, airway function tests, total lymphoid irradiation

Obliterative bronchiolitis after lung transplantation

Despite marked improvements in early survival, long-term outcome after lung transplantation is still threatened by obliterative bronchiolitis (OB). Thought to be a manifestation of chronic allograft rejection, OB affects up to 65% of patients at 5 years after surgery and produces a relentless airflow obstruction. Early and late acute rejection are the primary risk factors for OB, but cytomegalovirus infection and airway ischemia may also play a role. In most patients, OB responds poorly to augmented immunosuppression and eventually leads to infectious complications and terminal respiratory failure. Because early diagnosis is associated with better prognosis, every effort should be made to detect OB in a preclinical stage. This may be best achieved by combining several techniques, such as surveillance transbronchial biopsy and bronchoalveolar lavage, measurements of ventilation distribution and exhaled nitric oxide, and expiratory computed tomography.

Constrictive (obliterative) bronchiolitis: diagnosis, etiology, and a critical review of the literature

Constrictive bronchiolitis (CB) (or obliterative bronchiolitis) designates inflammation and fibrosis occurring predominantly in the walls and contiguous tissues of membranous and respiratory bronchioles, with resultant narrowing of their lumens. It differs from bronchiolitis obliterans-organizing pneumonia in its histopathology and clinical course. Most cases of CB occur in the setting of organ transplants, particularly lung and heart-lung transplants, but also in bone marrow transplants. Other bona fide cases are rare: infection, particularly viral infection, appears to be a well-documented precursor to CB in children, but not in immunocompetent adults. Constrictive bronchiolitis also has been reported in the course of rheumatoid arthritis, in certain other autoimmune diseases such as pemphigus vulgaris, after inhalation of toxic gases such as nitrogen oxide, after ingestion of certain drugs or medicinal agents such as Sauropus androgynous, and as a cryptogenic illness. Recent reports suggest that CB, as defined by clinical criteria (that is, bronchiolitis obliterans syndrome), is very common in lung allograft recipients who survive more than 5 years and, although it is associated with significant mortality, it also can be clinically stable. Furthermore, with the current practice of close monitoring of these patients, it appears that CB may now be diagnosed at an earlier stage, at which resolution, or at least stabilization of progression, is possible. A histopathologic diagnosis of CB in lung transplant and other patients may be difficult to make due to the patchy distribution of lesions, the technical difficulty in obtaining tissue in late lesions with extensive fibrosis, and the failure to recognize lesions. With regard to the last of these, in early stages of disease, CB may be subtle and easily missed in routine hematoxylin-eosin-stained specimens, while in advanced stages the disease may be equally difficult to diagnose if the patchy scarring in the lung is interpreted as nonspecific. The relative loss of bronchioles and the relationship of the scars to contiguous arteries should signal the need for elastic stains to look for the residual elastica of the bronchioles amidst the foci of fibrosis. Increasingly, clinical grounds, including pulmonary functions studies and high-resolution computed tomography findings, are proving to be relatively sensitive methods of detecting CB. Finally, the progressive airway destruction in chronic transplantation rejection appears to be a T-cell-mediated process. The "active" form of constrictive bronchiolitis, with attendant lymphocytic inflammation of the airways, likely precedes the "inactive" or scarred form of constrictive bronchiolitis.

Lung transplantation for cystic fibrosis

Lung transplantation currently stands as the only therapeutic option that carries the potential to restore patients with advanced cystic fibrosis to a more normal state of health. Nonetheless, the procedure carries significant risk and median survival following transplantation is only 5 years. This article discusses the currently achievable outcomes and the common short-comings of transplantation. Strategies to optimize outcomes through appropriate patient selection, use of living donors, and novel research initiatives are discussed.

Lung transplantation at the University of Lund 1990-1995. Analysis of the first 39 consecutive patients

Between 1990 and 1995 39 patients were lung transplanted at the University Hospital in Lund. This is a retrospective review of survival and lung function in these patients. There were 17 single-lung transplants (SLT), 21 double-lung transplants (DLT) and 1 heart-lung transplant (HLT). Seven patients died during the period, giving an overall survival of 82%. One-year survival according to Kaplan-Meier survival analysis was 87%, and 2-year survival was 83%. Vital capacity and forced expiratory volume in 1 s (FEV1) 1 year after transplantation were 91% and 100% of predicted, respectively, in the DLT group and 60% and 50% in the SLT group. Bronchiolitis obliterans syndrome (BOS) developed in 11 of the 35 patients (31%) surviving more than 6 months, 2/21 in the DLT group and 8/13 in the SLT group and in the patient with HLT. The median time until detection of BOS was 11 months after the operation (range 6-18 months). Working capacity 1 year after transplantation was 60% of predicted in the DLT group and 47% of predicted in the SLT group. Ventilatory capacity was no longer function limiting. Lung transplantation today is a therapeutic option with a good medium-term survival and good functional results in selected patients with severe lung disease.

Preoperative and postoperative imaging in the surgical management of pulmonary emphysema

For patients with emphysema, imaging studies have been useful for diagnostic purposes and for preoperative patient selection for surgical intervention, such as bullectomy, lung transplantation, and LVRS. Chest radiography is useful in evaluating hyperinflation. Inspiratory and expiratory films are used to estimate diaphragmatic excursion and air-trapping. CT scan is used to evaluate the anatomy and distribution of emphysema throughout the lungs, providing information clinically unobtainable by other means. Both imaging techniques are useful for detecting other disease processes. Radionuclide lung scanning also provides an estimate of target areas, volume occupying but nonfunctioning lung. Cohort studies utilizing these imaging techniques have demonstrated associations between preoperative characteristics and postoperative outcome. The imaging studies, especially the chest radiograph, have also played an important role in postoperative management. Many other imaging options are available, such as HRCT scan, quantitative CT scan, and single photon emission CT scan. Other techniques, such as MR imaging, may play a future role as well.

FK 506 'rescue' immunosuppression for obliterative bronchiolitis after lung transplantation

PRELIMINARY EXPERIENCE

In a consecutive case series (level V evidence) involving 10 recipients of unilateral lung transplantation (LT) with bronchiolitis obliterans, in conjunction with Fujisawa protocol 93-0-003, the physiologic responses to FK 506 (tacrolimus) "rescue" immunosuppression were assessed. Recipients were 22+/-18 months post-LT and demonstrated progressive allograft dysfunction that was refractory to pulsed-dose methylprednisolone therapy. All recipients received induction immunosuppression with Minnesota antilymphocyte globulin (10 to 15 mg/kg/d) for 5 to 10 days, cyclosporine (CsA) (whole-blood Abbott TDX fluorescence polarization immunoassay (Abbott Inc, Abbott Park, IL)=600 to 800 ng/mL), azathioprine (2 mg/kg/d), and prednisone (tapered to 0.2 mg/kg/d). The "rescue" regimen consisted of oral FK 506 adjusted to maintain a whole-blood Abbott IMX microparticle enzyme immunoassay (Abbott Inc, Abbott Park, IL) of 10 to 15 ng/mL with an initial increase in prednisone (1.0 mg/kg/d) during conversion that was subsequently tapered to 0.2 mg/kg/d. Spirometry was performed monthly in accordance with accepted American Thoracic Society criteria. Recipients were classified in accordance with the International Society for Heart and Lung Transplantation (ISHLT) "Working Formulation for Standardization of Nomenclature and for Clinical Staging of Chronic Dysfunction in Lung Allografts" as stages Ib (n=2), IIb (n=4), and IIIb (n=4) upon entry to the protocol. The deltaFEV1/month relationships during CsA- and FK 506-based regimens were analyzed by linear regression and compared by signed rank test (p<0.05).

RESULTS

The deltaFEV1/month slopes were -0.0687+/-0.0221 and +0.0300+/-0.033 L/mo (mean+/-SEM) for CsA and FK 506, respectively (p=0.037). Although no significant spirometric improvement was noted in most recipients, no further decline in FEV1 occurred after conversion to FK 506. Recipients with less severe chronic dysfunction (ie, obliterative bronchiolitis [OB] stages Ib and IIb) stabilized their spirometric indexes at higher levels. Two recipients with OB stage IIIb died of hypercapnic respiratory failure at 6 and 8 months after conversion.

CONCLUSIONS

The deltaFEV1/mo slopes stabilized after FK 506 conversion. Earlier conversion may be beneficial in stabilizing FEV1 at a higher plateau. Significant economic impact may be anticipated with FK 506 compared to alternative cytolytic strategies for OB. However, multicenter prospective controlled investigations are necessary to further address the potential role of FK 506 after LT (level I evidence). Furthermore, the ISHLT "Staging of OB Syndrome" may have significant clinical implications vis-à-vis prognosis and potential therapies.

Mycophenolate mofetil for obliterative bronchiolitis syndrome after lung transplantation

BACKGROUND

The development of obliterative bronchiolitis after lung transplantation portends a poor long-term outcome because of progressive decline in allograft function. There are currently no effective means of treating this condition.

METHODS

Thirteen patients in whom obliterative bronchiolitis syndrome developed after lung transplantation were treated with mycophenolate mofetil, an antimetabolite immunosuppressant, at a dose of 1.5 g orally twice daily. Patients were followed up clinically and with pulmonary function testing.

RESULTS

Duration of mycophenolate mofetil therapy ranged from 1 week to 24 months (mean duration, 11.4 months). Pulmonary function test results stabilized in the majority of patients with no significant further decline in forced expiratory volume in 1 second. Two patients died of progressive obliterative bronchiolitis, 1 patient is alive with progressive disease, and 1 patient died of an acute infection. The drug was discontinued in 2 additional patients. In no patient did severe leukopenia or cytomegalovirus infection develop; 1 patient had a fungal infection, and 7 patients experienced gastrointestinal side effects.

CONCLUSIONS

In the setting of obliterative bronchiolitis syndrome, mycophenolate mofetil is generally well tolerated and is associated with stabilization of pulmonary function test results. These findings suggest that the otherwise progressive process of obliterative bronchiolitis can be slowed.

Cytolytic therapy for the bronchiolitis obliterans syndrome complicating lung transplantation

The bronchiolitis obliterans syndrome (BOS) is the major cause of late morbidity and mortality after lung transplant (LTx). Previous studies suggest cytolytic therapy may be effective for the BOS but this therapy has not been proved effective or safe.

METHOD

A retrospective study of a predetermined treatment regimen to determine if the rate of fall in FEV1 can be reduced by corticosteroids and cytolytic therapy. Since August 1992, 10 to 65 long-term survivors of LTx (5 men, 5 women; mean age 36 +/- 10 years) developed BOS. All had previously had lymphocyte immune globulin, antithymocyte globulin (equine) (ATGAM sterile solution; Upjohn Pty Ltd; Sydney, Australia) induction therapy and corticosteroid avoidance for the first 7 to 10 days post-LTx. Therapy for the BOS was initiated with pulse methylprednisolone and ATGAM (aiming for an absolute CD3 count of < or - 100 cells per microliter for 5 days). ATGAM therapy was initiated at a mean 657 +/- 323 days post-LTx. Subsequent follow-up has been for 310 +/- 110 days (range, 163 to 530 days).

RESULTS

Nine of ten patients had a response with tolerable side effects. Preintervention, there was a linear fall in FEV1 of 0.22 +/- 0.15% predicted FEV1 per day (mean +/- SD) (range, 0.06 to 0.56%) compared with a postintervention linear fall of 0.036 +/- 0.019% predicted per day (range, 0 to 0.13%) (paired t test; p<0.005). This effect is sustained over the follow-up period.

CONCLUSION

The fall off in FEV1 that characterizes the BOS may be altered usefully by augmented immunotherapy. This effect can be rapid and sustained although it is neither completely arrested nor ever reversed. These data are preliminary but encourage a randomized control trial in the BOS.

Delayed development of obliterative bronchiolitis syndrome with OKT3 after unilateral lung transplantation. A plea for multicenter immunosuppressive trials

There is no consensus regarding the optimal induction immunosuppression regimen after lung transplantation (LT). In addition to the potential benefit of a reduced incidence of early acute allograft rejection, cytolytic induction immunosuppression may impact on long-term allograft function. We retrospectively assessed our incidence of obliterative bronchiolitis syndrome (OBS) stages Ia and IIa in LT survivors given two different cytolytic induction immunosuppression regimens: (between March 1989 and October 1990) OKT3 (5 mg/d)x10 to 14 days (n=11) vs (between November 1990 and April 1993) Minnesota antilymphocyte globulin (MALG) (10 to 15 mg/kgdx5 to 7 days. Cyclosporine (CSA) (whole blood polyclonal assay=600 to 800 ng/mL), azathioprine (1 to 2 mg/kg/d), and maintenance prednisone (0.2 mg/kg/d) were similar. Surveillance spirometry was performed monthly, in accordance with accepted American Thoracic Society criteria. Fiberoptic bronchoscopy with transbronchial biopsies (TBBs) were performed for clinical indications. Surveillance TBBs were not performed during the era of this study. As defined by the ISHLT "Working Formulation for the Standardization of Nomenclature and for Clinical Staging of Chronic Dysfunction in Lung Allografts," latencies to development of OBS stages Ia and IIa were determined by Kaplan-Meir analysis. Stepwise regression (Cox proportional hazards model) was performed for the variables: cytolytic induction regimen, episodes cytomegalovirus (CMV) pneumonitis, episodes CMV infection, serologic CMV donor (+): recipient (-) mismatch, prior pregnancy, HLA (A,B,DR +/- DQ) mismatches, episodes greater than grade A1 acute cellular rejection (ACR). We found that the OKT3 cohort experienced longer latencies for OBS stages Ia and IIa. Latencies to OBS stages Ia for OKT3 ve MALG were 962 +/- 65 vs 354 +/- 85 days (X +/- SEM) respectively. Brookmeyer-Crowley 95% confidence intervals for median latencies were 744 to 1,180 vs 266 to 510 days for OKT3 vs MALG, respectively. The Cox model was significant only for the variable of the induction cytolytic immunosuppression regimen (p=0.0015). By physiologic criteria, a longer course of OKT3 appeared superior to the short-course MALG protocol in delaying chronic lung allograft dysfunction. These effects may be related either to inherent differences in the antilymphocyte preparations or, alternatively, the difference in duration of treatment between groups. Surveillance TBB and treatment of detected occult ACR may serve to negate the observed differences in latencies for OBS.