2 died very early during TLI due to respiratory failure; 8 were stopped early (range 3-7 fractions) due to minor marrow suppression or infectious complications. The mean (sd) nadir leukocyte count was 2.98 (1.34) x 10 9 and platelet nadir 114 (41) x 10 6 . Seven (19%) required blood transfusion and only 2(5%) had serious infections as complica- tions. Duration of TLI course was mean (sd) 62.8 (41.7) days. Mean (sd) rate of decline in FEV1 was 122.7 (21.6) mls/month before TLI and 25.1(7.7) mls/month after TLI, (difference in rate of decline 95% CI 48.2-146.7), p=0.0004 (students paired t-test). Total survival in the 37 treated recipients is median (range) 59 (6-146) months and the post TLI survival is 27 (0-93) months. TLI is a well tolerated treatment with only mild marrow suppression and a low incidence of serious infection. It results in a significant reduction in the rate of FEV1 decline in rapidly progressive BOS. TLI should form part of the immunosuppressive armoury in patients with aggressive BOS. 241 THE USE OF BOSENTAN AND A PROSTACYCLIN ANALOG IN THE TREATMENT OF PRIMARY PULMONARY HYPERTENSION B.K. Rayburn, R.L. Benza, J.A. Tallaj, B.A. Foley, L.J. Pinderski, K.L. Thomas, R.C. Bourge, Medicine, University of Alabama at Birmingham, Birmingham, AL Purpose: Bosentan (B) is an ET receptor antagonist effective in the treatment of primary pulmonary hypertension (PPH). The prostacyclin analogs epoprostenol (epo) and treprostinil (tre) are also efficacious in these patients (pts). Data regarding the combined use of B and a prostacyclin analog are limited. Procedures: We added B to 23 pts with PPH receiving epo or tre. Pts included 18 women and 5 men, age 49 +/- 13 yrs, 16 receiving epo and 7 tre. Pts underwent a catheterization (RHC), echocardiogram (echo), 6 minute walk test (6 min), clinical assessment and labs at baseline. At 12 and 24 weeks (wks) 6 min, clinical assessment, labs and a repeat RHC/echo were done. Results: B was increased from 31.25 mg bid to 125 mg bid over 4 wks. To date, 21 and 10 pts have completed 12 and 24 wks of follow up, respectively. 6 min improved between baseline and the latest time point available (999 +/- 270 vs. 1094 +/- 347 ft, p=.03). RVEF improved significantly between baseline and 24 wks (27.1+/- 12 vs. 32.6 +/- 13, p=.02). 21 pts completed 12 wks follow up with significant reductions in PAS (80 vs 86, p=.008), PAD (34 vs 38, p=.01), mean PA (53 vs 57, p=.01) and PVR (609 vs 761, p=.0006). CO (5.2 vs 5.9, p=.002) and CI (2.8 vs 3.2, p=.002) improved significantly. In the 10 pts completing 24 wks follow up there remained significant reductions in PAS, PAD, mean PA and PVR and improvements in CO and CI. There were no changes in PCWP, BP or RA pressure at any time point. 73% of patients were in NYHA class3 at baseline vs 30 % and 39% at 12 and 24 wks. Conversely, 26% of patients were NYHA class 2 at baseline vs 60 % at 12 and 24 wks. There were no changes in labs, weight, SaO2 or diuretic use. Epo doses decreased from 47 +/- 78ng/kg/min to 29+/- 66 ng/kg/min by 6 mos. 3 pts died, 6 pts required dose reduction. Conclusion: The use of B in pts recieving epo/tre is safe and results in further clinical and hemodynamic improvements. 242 THE SAFETY AND EFFICACY OF BOSENTAN IN PULMONARY HYPERTENSION DUE TO CONGENITAL HEART DISEASE R.L. Benza, B.K. Rayburn, J.A. Tallaj, B.A. Foley, L.J. Pinderski, K.L. Thomas, R.C. Bourge, Medicine, University of Alabama at Birmingham, Birmingham, AL Purpose: Bosentan (B) is an ET receptor antagonist effective in the treatment of some forms pulmonary arterial hypertension (PAH). Few data exist regarding its use in PAH associated with congenital heart disease (PHC). We report our experience in treating PHC with B. Procedures: 14 pts with PHC were treated with B. Pts included 12 women and 2 men, age 50 +/- 14 yrs, 6 receiving treprostenil. The congenital defects included ASD’s, VSD’s and complex congenital pts. 6 pts were known to have an open shunt. Pts underwent a catheteriza- tion (RHC), echocardiogram (echo), 6 minute walk test (6 min), clinical assessment and labs at baseline, 12 and 24 weeks (wks). Results: B was increased from 31.25 mg bid to 125 mg bid over 4 wks. To date, 12 and 6 pts have completed 12 and 24 wks of follow up, respectively. There was no change in 6 min or RVEF over the study period. 12 pts completed 12 wks follow up with significant reductions in RV systolic pressure (107 vs 97, p=.03), PAS (97 vs 90, p=.02), mean PA (62 vs 57, p=.01) and PCWP (17 vs 12, p=.01). In the 6 pts completing 24 wks follow up there remained significant reductions in RVS, PAS, mean PA and PCWP. There were additional significant reductions in PAD (36 vs 26, p=.02), RVD (15 vs 11, p=.04) and RA (15 vs 10, p=.02). There were no changes in CO, CI, PVR, SVR and BP at any time point. 86% of patients were in NYHA class3 at baseline vs 64 % and 25% at 12 and 24 wks. Conversely, 14% of patients were NYHA class 2 at baseline vs 36 % and 75% at 12 and 24 wks. There were no changes in labs, weight, SaO2 or diuretic use. 1 pt stopped B due to malaise and 1 pt required dose reduction. No pts died. Conclusion: This first reported use of B in pts with PHC appears safe and results in clinical and hemodynamic improvements. 243 DIFFERENTIAL PROTEIN EXPRESSION IN PLEXOGENIC PULMONARY HYPERTENSIVE LUNG LESIONS M. Southwood, 1 C. Atkinson, 1 L. Long, 2 R. Pitman, 1 S. Stewart, 1 N. Morrell, 21 Pathology Department, Papworth Hospital, Cambridge, Cambridgeshire, United Kingdom; 2 Respiratory Medicine Unit, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom Background: Plexogenic pulmonary hypertension (PPH) is a devastat- ing disease with a complex aetiology, existing both as primary (PPPH) and secondary (SPPH) diseases, characterised by specific proliferative lesions within the pulmonary vasculature. We aim to identify and localise proteins implicated in the development of these lesions and evaluate differential protein expression between PPPH and SPPH patient groups. Method: Using an Affymetrix GeneChip array we identified 26 proteins up-regulated in plexogenic pulmonary hypertensive smooth muscle cell lines, compared to normal controls. Expression of tenas- cin-c, thrombomodulin and tumour necrosis factor apoptosis inducing ligand (TRAIL), each with a potential role in vascular remodelling and/or apoptosis were selected for investigation. The differential ex- pression within concentric and intimal plexiform lesions, in lung tissue from both SPPH patients (n=9) and PPPH patients (n=14), was assessed semi-quantitatively using immunohistochemistry. Results: Lesions from PPPH patients displayed an increased protein expression when compared to lesions from SPPH patients. Positive TRAIL expression is seen in 79% of SPPH plexiform lesions, 94% of PPPH plexiform lesions and in 67% and 90% of concentric lesions respectively. Positive tenascin-c expression is present in 44% of SPPH plexiform lesions, 76% of PPPH plexiform lesions and in 4% and 10% of concentric lesions respectively. Similarly, positive thrombomodulin expression is present in 55% of SPPH plexiform lesions, 90% of PPPH plexiform lesions and 52% and 60% of concentric lesions in SPPH and PPPH lesions respectively. Conclusion: The findings of increased expression of specific proteins, corresponding to genes identified by microarray analysis in PPPH, S152 Abstracts The Journal of Heart and Lung Transplantation January 2003