Abstracts S159 patients at risk for de novo DSA (dDSA) in a large cohort of lung transplant patients. Methods: We assessed 437 first-time lung transplant recipients from 1/2009-7/2013. Of these, 41 were excluded due to follow-up less than 1 month and 69 patients for multi-organ transplant, desensitization, or DSA within 14 days of transplant. Six more were excluded for DSA present prior to transplantation. DSA were prospectively tested at 1, 2, 3, 4, 5, 6, 9 and 12 months post-transplant and then every 4 months. Results: The remaining 327 recipients were primarily Caucasian (74%) with restrictive lung disease (60%). At a median of 4.2 months, 23.2% of recipients developed a dDSA. Of those, 13 were class I, 47 class II, and 16 both. The majority of dDSA were DQ (n= 52) followed by A (n= 15), B (n= 14), DR52/53 (n= 11), DR (n= 8), CW (n= 5), and DP (n= 2). Table 1 lists significant differences between those with dDSA and those without. No differences were detected in recipient age, diag- nosis, smoking history, double vs single lung, or ischemia time. After multi-variate analysis, only non-Caucasian race, having 2 of 2 HLA DQ mismatches, and a higher Lung Allocation Score (LAS) remained risk factors for dDSA (Table 2). Conclusion: In a large population of lung transplant recipients we identified a de novo DSA rate of 23%. Recipients who were non-Caucasian, mismatched at both DQ antigens, and had a higher LAS were found to be at a higher risk for dDSA. Increased monitoring of DSA may be warranted in these recipients. Table 1. Significant risk factors for dDSA in lung transplant recipients (univariate analysis) dDSA (n=76) No dDSA (n=251) p-value Age (median years ± SD) Race 60 ± 14.1 62 ± 11.9 0.215 –African American 14 (18.4%) 25 (10.0%) 0.046 –Hispanic 9 (11.8%) 26 (10.4%) 0.714 –Caucasian 47 (61.8%) 194 (77.3%) 0.007 –Other 6 (7.9%) 6 (2.4%) 0.025 Lung Allocation Score (LAS) (median ± SD) 38.6 ± 17.3 36.8 ± 13.3 0.014 Ischemic time (average when double) (median ± SD) 212 ± 51 204 ± 62 0.672 CMV high risk (donor+/ recipient-) 11 (14.7%) 57 (23.2%) 0.115 HLA A-B-DR mismatch/6 (mean ± SD) 5.0 ± 1.1 5.0 ± 1.1 0.444 HLA A-B-DR-DQ mismatch/8 (mean ± SD) 6.0 ± 1.3 6.0 ± 1.4 0.070 HLA DQ mismatch 2/2 37 (49.3%) 77 (31.4%) 0.005 Table 2. Significant risk factors for dDSA in lung transplant recipients (multivariate analysis) Characteristics Odds Ratio p-value Non-Caucasian race 2.11 0.010 HLA DQ mismatch 2/2 2.15 0.005 LAS per 10 point increase 1.18 0.053 ( 421) The Development of De Novo Donor Specific Antibodies Following Community Acquired Respiratory Virus Infection after Lung Transplantation: A Novel Association H.W. Ainge-Allen , M. Benzimra, A.P. Havryk, A.L. Rigby, M.A. Malouf, M. Plit, A.R. Glanville. Lung Transplant Unit, St Vincent’s Hospital, Sydney, Australia. Purpose: The etiology of late de novo donor specific antibodies (DSA) following lung transplantation (LTX) remains a source of speculation. 2. ACM patients undergoing HT in era 2 were older (p<0.0001), had higher body mass index (p=0.0006), and were more likely to be African American (p<0.0001), UNOS Status 1A (p<0.0001), male (p=0.016), and highly sensi- tized (p<0.0001) than those undergoing HT in era 1. Compared to patients with other etiologies of RCM (n=703 in era 1, n=394 in era 2), the adjusted HRs for post-HT mortality of ACM were 1.9 (p<0.0001) in era 1 and 1.0 (p=NS) in era 2. The adjusted HRs for mortality of ACM vs all other etiologies of heart failure (n=42,737 in era 1, n=11,431 in era 2) were 1.7 (p<0.0001) in era 1 and 1.3 (p=NS) in era 2. While post-HT survival did not change between era 1 and era 2 among non-ACM RCM (HR 0.85, p=NS), post-HT survival was signifi- cantly better in era 2 than in era 1 among ACM patients (HR 0.48, P=0.015). Conclusion: Post-HT outcomes of ACM patients have markedly improved in recent years in conjunction with more effective chemotherapy regimens for AL amyloid and with changes in patient selection. Outcomes among this population in the modern era are equivalent to those of non-ACM RCM patients and approach those of non-RCM patients. ( 419) Postoperative Donor Specific Anti-HLA Antibodies in Lung Transplantation: Risk Factors and Impact on Mid-Term Patient and Graft Outcomes F. Ius , 1 W. Sommer, 1 I. Tudorache, 1 C. Kühn, 1 M. Avsar, 1 T. Siemeni, 1 J. Salman, 1 M. Hallensleben, 2 M. Greer, 3 J. Gottlieb, 3 A. Haverich, 1 G. Warnecke. 1 1 Department of Cardiothoracic, Transplant and Vascular Surgery, Hannover Medical School, Hannover, Germany; 2 Department of Transfusion Medicine, Hannover Medical School, Hannover, Germany; 3 Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany. Purpose: After lung transplantation the impact of donor specific anti-HLA antibodies (DSA) on patient and graft survival is still controversial. Aim of this study was to analyze the risk factors for DSA development and to com- pare mid-term outcomes in patients with or without DSA. Methods: Between January 2009 and August 2013, 544 patients underwent lung transplantation at our Institution. Ninety-seven (18%) patients showed DSA postoperatively (Group A), 447 (82%) patients (Group B) did not. DSA were detected by the Luminex assay. Patient postoperative and follow-up records were retrospectively reviewed. Binary logistic regression analysis was used to identify independent risk factors for DSA development and overall mortality. Results: Re-transplantation (OR=2.5; 95% confidence interval [CI] 1.1 to 5.7 p=0.03), preoperative anti-HLA antibodies (OR=2.0; 95% CI 1.2 to 3.2 p=0.008) and primary graft dysfunction (PGD) score grade 2-3 at 48 hours after transplantation (OR=2.7; 95% CI 1.6 to 4.8 p < 0.01) were independ- ent risk factors for postoperative DSA development. Mean follow-up was 23±16 months. At 1 and 3 years, overall survival (%) was 78±4.5 vs 88±2 and 57±8 vs 74±3, in Group A and B, respectively (p=0.01). Only postoperative dialysis (OR=44; 95% CI 4 to 525 p = 0.003) and acute rejection (OR=9; 95% CI 1.2 to 67.2 p = 0.03) were independent risk factors for mortality. At 1 and 3 years freedom from BOS (%) grade 1-3 was 84±4 vs 90±1 and 55±9 vs 51±3 (p = 0.5), and from acute rejection (%) 47±6 vs 45±3 and 37±8 vs 26±3 (p = 0.18), in Group A and B, respectively. At 1-year follow-up, forced expiratory volume at 1 second (% threshold) was 75±19 vs 82±24, in Group A and B, respectively (p = 0.09). Conclusion: Patients with preoperative antibodies or re-transplantation are at higher risk for developing DSA postoperatively. Primary graft dysfunc- tion augments DSA development. While patient survival differs significantly between groups, multivariate analysis does not detect DSA as independent risk factor. Further study on the role of DSA after lung transplantation is warranted. ( 420) Identification of Independent Risk Factors for De Novo DSA Development Through Prospective Monitoring A.K. Islam , S. Jyothula, J. Devos, L. Teeter, E. Graviss, L. Moore, N. Sinha, T. Kaleekal, B. Mankidy, S. Scheinin, M. Loebe, B. Bruckner, D. Ren, A.O. Gaber. Houston Methodist, Houston, TX. Purpose: Donor specific antibodies (DSA) after lung transplant have been associated with worse outcomes. The purpose of our study was to identify