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Background Patients with Tetralogy of Fallot with pulmonary stenosis (ToF/PS), the most common form of cyanotic congenital heart disease (CHD), develop adverse right ventricular (RV) remodeling, leading to late heart failure and arrhythmia. We recently demonstrated that overactive β-adrenergic receptor signaling inhibits cardiomyocyte division in ToF/PS infants, providing a conceptual basis for the hypothesis that treatment with the β-adrenergic receptor blocker, propranolol, early in life would increase cardiomyocyte division. No data are available in ToF/PS infants on the efficacy of propranolol as a possible novel therapeutic option to increase cardiomyocyte division and potentially reduce adverse RV remodeling. Methods Using a randomized, double-blind, placebo-controlled trial, we will evaluate the effect of propranolol administration on reactivating cardiomyocyte proliferation to prevent adverse RV remodeling in 40 infants with ToF/PS. Propranolol administration (1 mg/kg po QID) will begin at 1 month of age and last until surgical repair. The primary endpoint is cardiomyocyte division, quantified after 15N-thymidine administration with Multi-isotope Imaging Mass Spectrometry (MIMS) analysis of resected myocardial specimens. The secondary endpoints are changes in RV myocardial and cardiomyocyte hypertrophy. Conclusion This trial will be the first study in humans to assess whether cardiomyocyte proliferation can be pharmacologically increased. If successful, the results could introduce a paradigm shift in the management of patients with ToF/PS from a purely surgical approach, to synergistic medical and surgical management. It will provide the basis for future multi-center randomized controlled trials of propranolol administration in infants with ToF/PS and other types of CHD with RV hypertension. Clinical trial registration: The trial protocol was registered at clinicaltrials.gov (NCT04713657).

We introduce a model for auto-complete of general queries via Bayesian inference. To that end, we address three issues: First, the problem of predicting a word given previous words in a text. Usually, the context words are treated as a directional sequence. In our approach, we introduce a set-based class language model with order-independence, modeling the context words as a set of classes. Second, towards the task of predicting the next word’s class based on the classes of previous words plus an incomplete word prefix, we present a Bayesian framework that incorporates the set-based class language model in conjunction with an ontology. Third, regarding the auto-complete problem, we provide complete query suggestions via abstract class-space search which determines similar historical queries that contain the classes of previous words plus the next word’s predicted class. Subsequently, we apply the model to auto-complete inference in a system setting, in which users can access data via natural language queries.

HLA haplotype mismatches have been associated with an elevated risk of acute graft-versus-host disease (aGVHD) in patients undergoing HLA-matched unrelated donor (URD) hematopoietic cell transplantation (HCT). The gamma block (GB) is located in the central MHC region between beta and delta blocks (encoding HLA-B and -C and HLA-DQ and -DR antigens, respectively) and contains numerous inflammatory and immune regulatory genes, including Bf, C2, and C4 genes. A single-center study showed that mismatches in SNPs c.2918+98G, c.3316C, and c.4385C in the GB block (C4 SNPs) were associated with higher risk of grade III-IV aGVHD. We investigated the association of GB SNP (GBS) mismatches with outcomes after 10/10 and 9/10 URD HCT (n = 714). The primary outcome was acute GVHD. Overall survival, disease-free survival, transplantation-related mortality, relapse, chronic GVHD, and engraftment were also analyzed. DNA samples were GBS genotyped by identifying 338 SNPs across 20 kb using the Illumina NGS platform. The overall 100-day incidence of aGVHD grade II-IV and II-IV were 41% and 17%, respectively. The overall incidence of matching at all GBSs tested and at the C4 SNPs were 23% and 81%, respectively. Neither being matched across all GB SNPs tested (versus mismatched) nor having a higher number of GBS mismatches was associated with transplantation outcomes. There was no association between C4 SNP mismatches and outcomes except for an unexpected significant association between having 2 C4 SNP mismatches and a higher hazard ratio (HR) for relapse (association seen in 15 patients only; HR, 3.38, 95% confidence interval, 1.75 to 6.53; P = .0003). These data do not support the hypothesis that mismatching at GB is associated with outcomes after HCT.

Natural killer (NK) cells are regulated by killer immunoglobulin-like receptor (KIR) interactions with human leukocyte antigen class I ligands. Various models of NK cell alloreactivity have been associated with outcomes after allogeneic hematopoietic cell transplant (alloHCT), but results have varied widely. We hypothesized that somatic mutations in acute myeloid leukemia (AML) in the context of KIR profiles may further refine their association with transplant outcomes. In this single-center, retrospective, observational study, 81 AML patients who underwent matched-related donor alloHCT were included. Post-HCT outcomes were assessed based on mutational status and KIR profiles with the Kaplan–Meier method and log-rank test. On multivariable analysis those with any somatic mutations and C1/C2 heterozygosity had less acute graft-versus-host disease (GvHD) (hazard ratio [HR], 0.32; 95% confidence interval [CI], 0.14-0.75; P = .009), more relapse (HR, 3.02; 95% CI, 1.30-7.01; P = .010), inferior relapse-free survival (RFS; HR, 2.22; 95% CI, 1.17-4.20; P = .014), and overall survival (OS; HR, 2.21; 95% CI, 1.17-4.20; P = .015), whereas those with a missing KIR ligand had superior RFS (HR, 0.53; 95% CI, 0.30-0.94; P = .031). The presence of a somatic mutation and donor haplotype A was also associated with less acute GvHD (HR, 0.38; 95% CI, 0.16-0.92; P = .032), more relapse (HR, 2.72; 95% CI, 1.13-6.52; P = .025), inferior RFS (HR, 2.11; 95% CI, 1.07-4.14; P = .030), and OS (HR, 2.20; 95% CI, 1.11-4.38; P = .024). Enhanced NK cell alloreactivity from more KIR activating signals (donor B haplotype) and fewer inhibitory signals (recipient missing KIR ligand or C1 or C2 homozygosity) may help mitigate the adverse prognosis associated with some AML somatic mutations. These results may have implications for improving patient risk stratification prior to transplant and optimizing donor selection.

Natural language query understanding for unstructured textual sources has seen significant progress over the last couple of decades. For structured data, while the ecosystem has evolved with regard to data storage and retrieval mechanisms, the query language has remained predominantly SQL (or SQL-like). Towards making the latter more natural there has been recent research emphasis on Natural Language Interface to DataBases (NLIDB) systems. Piggybacking on the rise of 'deep learning' systems, the state-of-the-art NLIDB solutions over large parallel and standard benchmarks (viz, WikiSQL and Spider) primarily rely on attention based sequence-to-sequence models. Building industry grade NLIDB solutions for making big data ecosystem accessible by truly natural and unstructured querying mechanism presents several challenges. These include lack of availability of parallel corpora, diversity in underlying data schema, wide variability in the nature of queries to context and dialog management in interactive systems. In this paper, we present an end-to-end system Query Enterprise Data (QED) towards making enterprise descriptive analytics and reporting easier and natural. We elaborate in detail how we addressed the challenges mentioned above and novel features such as handling incomplete queries in incremental fashion as well as highlight the role of an assistive user interface that provides a better user experience. Finally, we conclude the paper with observations and lessons learnt from the experience of transferring and deploying a research solution to industry grade practical deployment.

With seven billion mobile phone subscriptions and a third of the world's population going online, digital information and communication technologies present untapped platforms for communication, learning and empowerment. Newer technologies such as mobile phones, the internet and computers have the potential to contribute significantly to the prevention of violence against children. Yet, efforts to date have focused primarily on the risks associated with them. It is important to consider how digital technologies can enhance social and behaviour change interventions to prevent and respond to violence against children. We conducted a systematic review of social and behaviour change interventions addressing violence against children. We searched five databases for peer-reviewed and grey literature published between 2000 and 2015, which yielded 18 manuscripts relevant to the use of computers, the internet or mobile phones. Digital technologies were typically combined with other communication channels in order to reach children, parents, teachers or service providers. We are unable to draw any conclusions on the direct effectiveness of digital technologies, indicating the need for more rigorous evaluations to assess their added value. Future work should explore how digital technologies can be integrated into programmes disseminating information, raising awareness, helping individuals report violence and mobilising communities to action. Copyright © 2017 John Wiley & Sons, Ltd. Key Practitioner Messages Successful violence prevention programmes are not taking full advantage of digital technologies. Adapting programmes and messages for computer, internet or mobile phone delivery would broaden their scope and reach. The interactive nature of digital technologies makes them ideally suited to involve and empower individuals and entire communities for change. The effectiveness of digital technologies in preventing violence against children is still unclear. More investment in research and evaluation is needed. ‘A systematic review of social and behaviour change interventions addressing violence against children’ ‘The effectiveness of digital technologies in preventing violence against children is still unclear’

Objective/Background: Cytomegalovirus (CMV) infection and disease are common infectious complications after allogeneic hematopoietic cell transplantation (alloHCT). Major histocompatibility complex (MHC) class I chain-related gene A (MICA) is a ligand of the natural killer (NKG2D) receptor on immune effector cells that helps mediate NK cell alloreactivity. We hypothesized that MICA polymorphisms may influence CMV infection and disease incidence after alloHCT. Methods: We conducted a retrospective analysis of 423 adults at the Cleveland Clinic with hematologic malignancies treated with a matched related or unrelated donor alloHCT. CMV cases analyzed included a compositive of instances of viral copy replication above detection limits as well as any biopsy-proven tissue invasive disease episodes. Genotypes at the MICA-129 position have been categorized as weak (valine/valine; V/V), intermediate (methionine/valine; M/V), or strong (methionine/methionine; M/M) receptor affinity. Results: In multivariable analysis, V/V donor MICA-129 genotype was associated with CMV infection and disease (hazard ratio [HR] = 1.40; 95% confidence interval [CI], 1.00–1.96; p = .05), but not MICA mismatch (HR = 1.38; 95% CI, 0.83–2.29; p = .22). There was no association of acute or chronic GVHD with MICA donor–recipient mismatch (HR = 1.05; 95% 95% CI, 0.66–1.68; p = .83 and HR = 0.94; 95% CI, 0.51–1.76; p = .85, respectively) or V/V donor MICA-129 genotypes (HR = 1.02; 95% CI, 0.79–1.31; p = .89 and HR = 0.89; 95% CI, 0.65–1.22; p = .47, respectively). Conclusion: These findings suggest that the donor MICA-129 V/V genotype with weak NKG2D receptor binding affinity is associated with an increased risk of CMV infection and disease after alloHCT. Keywords: Allogeneic hematopoietic cell transplantation, Cytomegalovirus, Killer cell immunoglobulin-like receptors, Major histocompatibility complex class I chain-related gene A

We report a case of primary renal allograft dysfunction and early acute cell-mediated rejection after a 12/12 HLA antigen zero-mismatch (0MM) transplant. The recipient was a 40-year-old white man who was highly allosensitized, with a calculated panel reactive antibody score of 100%. In posteroperative day 1 the recipient remained anuric and underwent dialysis because of hyperkalemia. Graft biopsy showed early acute cellular rejection, Banff grade 2B. No evidence of antibody-mediated rejection was observed. To our knowledge, this case is the 1st to report early cell-mediated rejection after 12/12 HLA antigen 0MM kidney transplantation. This case suggests that highly sensitized candidates are at high immunologic risk even in the context of 0MM kidney transplantation.

The clinical relevance of mismatches at the MHC class I–related chain A (MICA) in hematopoietic stem cell transplantation (HSCT) remains unclear. We investigated the association of MICA donor/recipient mismatch and whether there is an interaction between these and HLA-DPB1 mismatch on clinical outcomes after unrelated donor HSCT. Our study included 227 patients who underwent unrelated donor allogeneic HSCT at our institution between 2000 and 2010. Among these, 177 (78%) received HSCT from a 10/10 HLA-matched donor. MICA genotyping was performed using commercially available kits. In univariable analysis, the risk of grade II to IV acute graft-versus-host disease (GVHD) was greater for patients with MICA mismatch (hazard ratio [HR], 1.73; P = .02) than for those with HLA-DPB1 mismatch (HR, 1.62; P = .07). When MICA and HLA-DPB1 were assessed simultaneously, patients mismatched at both loci had the greatest risk (HR, 2.51; P < .01) and those mismatched at only 1 locus had somewhat greater risk (HR, 1.53; P = .12) than patients matched at both loci; this remained significant in multivariable analysis. The 100-day incidence was 66%, 45%, and 31%, respectively (P = .03). Results were similar for grade III and IV acute GVHD, with 100-day incidence 34%, 16%, and 8% (P = .01). These results are clinically pertinent to donor selection strategies and indicate that patients with mismatch at both MICA and HLA-DPB1 are at increased risk for acute GVHD.

Aim Development of de novo HLA donor-specific antibody (dnDSA) after lung transplant (LuTx) is prevalent and associated with poorer transplant outcomes. Understanding pre-LuTx determinants helps to minimize dnDSA. The aim of this study was to investigate the impact of HLA-Epitope Mismatch Load (EpiMML) in the development of dnDSA in LuTx recipients. Methods 572 recipients received LuTx during 10/2012–10/2017 and were retrospectively analyzed for the formation of dnDSA (Mean Fluorescence Intensity ⩾ 1000). Antigenic mismatches were recorded among 422 recipients. EpiMMLs were determined by HLA-Matchmaker (Version 02) among 168 recipients who had four-digit high resolution typing. There were 18 recipients who were typed by both high and low resolution. Acute Cellular Rejection (ACR) and Antibody Mediated Rejection (AMR) were assessed for LuTx outcomes. Results Of the 572 patients, 55% developed dnDSA; 25% Class I, 39% Class II, and 36% both Class I and II. In Class II, the most prevalent dnDSA was DQ (216/235; 92%). EpiMMLs for Class I, Class II, as well as single loci of HLA-A, B, C, DR, and DQ were all significantly higher from patients with positive dnDSA than from patient with negative dnDSA (Table 1a). However, for antigen-level mismatches, only HLA-A and DQ correlated with the development of dnDSA. As shown in Table 1b, certain mismatched epitopes were more frequent among patients who developed dnDSA than those who did not. Among a subgroup of 120 recipients, EpiMMLs of Class II, especially DQ, were significantly associated with the occurrence of ACR (p = 0.02 and 0.005, respectively). There was no remarkable relevance between EpiMMLs and AMR. Conclusions Compared to HLA antigen mismatching, EpiMML is a better predictor of dnDSA development in LuTx recipients. Increasing EpiMMLs, particularly for HLA-DQ, identify patients at the highest risk to develop dnDSA and ACR. Collectively, these data support the use of EpiMML assessment especially for optimizing post-transplantation immunosuppression in LuTx recipients. Download : Download high-res image (242KB) Download : Download full-size image Download : Download high-res image (182KB) Download : Download full-size image

Background: Graft-versus-leukemia (GVL) responses after allogeneic hematopoietic cell transplantation (alloHCT) for AML are mediated by alloreactive donor-derived immune effector cells including T lymphocytes and natural killer (NK) cells. The function of NK cells is regulated by inhibitory and activating signals mediated through cell-surface receptors, including KIRs. Various models of NK cell alloreactivity have been associated with post-transplant outcomes, including leukemia relapse. However, these results have varied widely between different investigators employing similar models of NK cell alloreactivity. Assessment of somatic mutations in AML on post-transplant outcomes has not been investigated in the context of KIR profiles. Methods: In this single-institution retrospective cohort study, we investigated KIR haplotypes (haplotype AA vs. Bx [associated with multiple activating KIRs]; Cooley S., et al. Blood. 113:726-732. 2009) in the context of somatic mutations. We included 34 adult patients with AML who underwent alloHCT from a matched related donor from 2006 to 2013. A targeted multi-amplicon deep NGS panel of 79 commonly mutated genes in myeloid neoplasia was performed. Post-HCT outcomes were assessed based on mutational status and KIR haplotype with Kaplan-Meier method and log-rank test. Results: Median age at transplant was 54 (range 31-73). Cytogenetic risk groups were 9% favorable, 56% intermediate, and 35% poor based on 2017 ELN classification. HCT-CI scores included 26% low, 32% intermediate, and 41% high. Disease risk group defined by ASTCT included 71% low, 26% intermediate, and 3% high. Disease status at HCT included 74% CR1 and 26% CR2. Frequencies of somatic mutations prior to HCT were: 21% DNMT3A, 18% IDH2, 9% each for STAG2 and NRAS, 6% each for ASXL1, JAK2, PHF6, RUNX1, TET2, and 3% each for CBL, FLT3, NPM1, and U2AF1. Overall, 53% of patients had at least 1 mutation: 24%, 18%, 9%, and 3% of patients had 1, 2, 3, and 4 mutations, respectively. 41% were carriers of KIR haplotype AA, and 59% were haplotype Bx. Relapse (p=0.40), relapse-free (p=0.33), and overall survival (p=0.30) between haplotypes AA and Bx were not statistically different. However, when considering somatic mutations in the context of KIR haplotypes, those with any somatic mutation (n= 18) present had inferior relapse-free (p=0.002) and overall survival (p=0.002; figures A-B) as compared to those with none. Further assessment of outcomes was then considered for those who had the following poor prognostic mutations (n=12): ASXL1, DNMT3A, FLT3, NRAS, RUNX1, and TET2. KIR haplotype AA with one or more of these mutations was associated with inferior relapse-free (p=0.05) and overall survival (p=0.008). At median follow-up of 83 (range 66-137) months, 38% were alive. Non-relapse mortality rates were 21% (9-36) at 1 year and 29% (15-39) at 3 years. The most common causes of death for all patients were relapse (48%) followed by infection (33%). Conclusion: In presence of somatic mutations, carrying KIR haplotypes Bx was associated with better survival in AML post-alloHCT. The presence of multiple activating KIRs may also help mitigate the worse prognosis associated with some of the more deleterious somatic mutations in AML. These observations may have implications for improving patient risk stratification prior to transplant and optimizing donor selection. Future investigation with larger cohorts interrogating KIR haplotypes in the context of pre-transplant AML somatic mutations on post-transplant outcomes may further elucidate which patients may benefit most from transplant. Disclosures Nazha: Tolero, Karyopharma: Honoraria; Abbvie: Consultancy; Daiichi Sankyo: Consultancy; Novartis: Speakers Bureau; Jazz Pharmacutical: Research Funding; Incyte: Speakers Bureau; MEI: Other: Data monitoring Committee. Mukherjee:Bristol-Myers Squibb: Speakers Bureau; Projects in Knowledge: Honoraria; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Partnership for Health Analytic Research, LLC (PHAR, LLC): Consultancy; McGraw Hill Hematology Oncology Board Review: Other: Editor; Pfizer: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees. Advani:Pfizer: Honoraria, Research Funding; Macrogenics: Research Funding; Glycomimetics: Consultancy, Research Funding; Kite Pharmaceuticals: Consultancy; Amgen: Research Funding; Abbvie: Research Funding. Gerds:Sierra Oncology: Research Funding; Incyte: Consultancy, Research Funding; CTI Biopharma: Consultancy, Research Funding; Imago Biosciences: Research Funding; Celgene Corporation: Consultancy, Research Funding; Roche: Research Funding; Pfizer: Consultancy. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees. Majhail:Mallinckrodt: Honoraria; Atara Bio: Consultancy; Anthem, Inc.: Consultancy; Nkarta: Consultancy; Incyte: Consultancy. Maciejewski:Novartis: Consultancy; Alexion: Consultancy.

The National Lung Screening Trial (NLST) is a randomized multicenter study comparing low-dose helical computed tomography (CT) with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer, which is the leading cause of cancer-related death in the United States. Five-year survival rates approach 70% with surgical resection of stage IA disease; however, more than 75% of individuals have incurable locally advanced or metastatic disease, the latter having a 5-year survival of less than 5%. It is plausible that treatment should be more effective and the likelihood of death decreased if asymptomatic lung cancer is detected through screening early enough in its preclinical phase. For these reasons, there is intense interest and intuitive appeal in lung cancer screening with low-dose CT. The use of survival as the determinant of screening effectiveness is, however, confounded by the well-described biases of lead time, length, and overdiagnosis. Despite previous attempts, no test has been shown to reduce lung cancer mortality, an endpoint that circumvents screening biases and provides a definitive measure of benefit when assessed in a randomized controlled trial that enables comparison of mortality rates between screened individuals and a control group that does not undergo the screening intervention of interest. The NLST is such a trial. The rationale for and design of the NLST are presented.

Background MHC class I chain-related gene A (MICA) is a polymorphic ligand of the natural killer (NKG2D) receptor on immune effector cells. The activating NKG2D receptor controls immune responses by regulating NK cells, NKT cells and γδ-T cells. Dimorphisms at sequence position 129 of the MICA gene confers varying levels of binding affinity to NKG2D receptor. MICA previously has been associated with post-allogeneic hematopoietic cell transplantation (alloHCT) outcomes including graft-versus-host-disease (GvHD), infection, and relapse. However, it is unclear how MICA interacts with cytogenetic and somatic mutations in regards to these outcomes in acute myeloid leukemia (AML). Methods We conducted a single center, retrospective analysis of adult AML patients in first or second complete remission (CR1, CR2), who underwent T-cell replete matched related or unrelated donor alloHCT. Analysis was limited to those who had MICA data available for donors and recipients. In addition to cytogenetic risk group stratification by European LeukemiaNet criteria (Döhner H, et al, Blood 2016), a subset of patients had a 36-gene somatic mutation panel assessed prior to alloHCT by next-generation sequencing. Dimorphisms at the MICA-129 position have previously been categorized as weaker (valine/valine: V/V), heterozygous (methionine/valine: M/V), or stronger (methionine/methionine: M/M) receptor binding affinity. Fine and Gray or Cox regression was used to identify the association of MICA and outcomes with results as hazard ratios (HR) and 95% confidence intervals (CI). Results From 2000 - 2017, 131 AML patients were identified meeting inclusion criteria. Median age at transplant was 54 years (18-74), with 98% Caucasian. Disease status at transplant included 78% CR1 and 22% CR2. Cytogenetic risk stratification showed 13% of patients as favorable, 56% as intermediate, and 31% as adverse-risk. The five most common somatic mutations were FLT3 (15%), NPM1 (14%), DNMT3A (11%), TET2 (7%), and NRAS (6%). 60% of patients had a related donor. A myeloablative transplant was performed in 84% of patients and 53% had a bone marrow graft source. The most common conditioning regimen used was busulfan/cyclophosphamide (52%). 12% of patients were MICA mismatched with their donor. The distribution of donor MICA-129 polymorphisms were 41% V/V, 53% M/V, and 6% M/M. In univariable analysis, donor-recipient MICA mismatch tended to be associated with a lower risk of infection (HR 0.49, CI 0.23-1.02, P=0.06) and grade 2-4 acute GvHD (HR 0.25, CI 0.06-1.04, P=0.06) but was not associated with other post-transplant outcomes. In multivariable analysis, donor MICA-129 V/V was associated with a higher risk of non-relapse mortality (NRM) (HR 2.02, CI 1.01-4.05, P=0.047) (Figure 1) along with increasing patient age at transplant (HR 1.46, CI 1.10-1.93, p=0.008) and the presence of a TET2 mutation (HR 6.00, CI 1.77-20.3, P=0.004). There were no differences between the V/V and the M/V+M/M cohorts regarding somatic mutational status, cytogenetics and other pre-transplant characteristics and post-transplant outcomes. With a median follow-up of 65 months for both cohorts, 45% vs. 49% of patients remain alive, respectively. The most common causes of death between the V/V and the M/V+M/M cohorts was relapse (38% vs. 62%) and infection (31% vs. 8%), respectively. Conclusion While previous studies have demonstrated associations of somatic mutations and cytogenetics with survival outcomes after alloHCT for AML, we observed mutations in TET2 and the V/V donor MICA-129 polymorphism to be independently prognostic for NRM. Mechanistic studies may be considered to assess for possible interactions of TET2 mutations with NK cell alloreactivity. The weaker binding affinity to the NKG2D receptor by the V/V phenotype may diminish immune responses against pathogens that subsequently contribute to higher NRM. These observations may have implications for enhancing patient risk stratification prior to transplant and optimizing donor selection. Future investigation with larger cohorts interrogating pre-transplant AML somatic mutations with MICA polymorphisms on post-transplant outcomes may further elucidate which subsets of patients may benefit most from transplant. Disclosures Nazha: MEI: Consultancy. Mukherjee:Pfizer: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Projects in Knowledge: Honoraria; BioPharm Communications: Consultancy; Bristol Myers Squib: Honoraria, Speakers Bureau; Takeda Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; LEK Consulting: Consultancy, Honoraria; Aplastic Anemia & MDS International Foundation in Joint Partnership with Cleveland Clinic Taussig Cancer Institute: Honoraria. Advani:Amgen: Research Funding; Pfizer: Honoraria, Research Funding; Glycomimetics: Consultancy; Novartis: Consultancy. Carraway:Novartis: Speakers Bureau; Balaxa: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Speakers Bureau; FibroGen: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Speakers Bureau. Gerds:Apexx Oncology: Consultancy; Celgene: Consultancy; Incyte: Consultancy; CTI Biopharma: Consultancy. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees. Maciejewski:Apellis Pharmaceuticals: Consultancy; Ra Pharmaceuticals, Inc: Consultancy; Alexion Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Ra Pharmaceuticals, Inc: Consultancy; Alexion Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Apellis Pharmaceuticals: Consultancy. Majhail:Incyte: Honoraria; Anthem, Inc.: Consultancy; Atara: Honoraria.

Background While allogeneic hematopoietic cell transplantation (alloHCT) can be curative for patients with acute myeloid leukemia (AML), relapse remains a significant challenge. Previous work has suggested that disease status at time of transplant and cytogenetics are important predictors of relapse. However, it is unclear if common somatic mutations or dimorphisms of MHC class I chain-related gene A (MICA), a ligand of the natural killer (NKG2D) receptor on immune effector cells that helps mediate NK cell alloreactivity, also contribute. Moreover, the mechanisms of early relapse are an area of ongoing investigation. We assessed risk factors for relapse within 6 and 12 months after alloHCT. Methods We conducted a single center, retrospective analysis of adults with AML who underwent a first alloHCT. Analysis was restricted to patients with T-cell replete HLA-8/8 matched related or unrelated donor. In addition to cytogenetic risk group stratification by European LeukemiaNet criteria (Döhner H, et al, Blood 2016), a subset of patients had a 36-gene somatic mutation panel assessed prior to alloHCT by next-generation sequencing. Dimorphisms at the MICA-129 position have previously been categorized as weaker (valine/valine: V/V), heterozygous (methionine/valine: M/V), or stronger (methionine/methionine: M/M) receptor binding affinity. Risk factors for early relapse were assessed with Fine and Gray competing risk regression with results as hazard ratios (HR) and 95% confidence intervals (CI). Results From 2000 - 2017, 319 adult AML patients were identified meeting inclusion criteria. Median age at transplant was 51 years (range, 18-74), with 95% Caucasian. The distribution of low, intermediate, and high HCT-CI scores was 28%, 28%, and 44%, respectively. 75% of patients were transplanted ≤12 months from diagnosis. Disease status at transplant included 48% in first complete remission (CR1), 19% in second CR (CR2), 33% in third CR or relapsed/refractory or untreated (collectively, In univariable analysis, non-Caucasian race, disease status Conclusion Relapse after alloHCT for AML remains a challenge. In our study, the strongest risk factors for early relapse after alloHCT remains absence of CR1 disease status at transplant and adverse-risk cytogenetics. We observed no prognostic effect of somatic mutations nor MICA dimorphisms prior to transplant on 6 or 12-month relapse post-transplant. Further interrogation of pre-transplant or post-transplant persistence of somatic mutations in a larger series may better risk stratify subjects who may benefit from more intensive or innovative approaches to prevent post-transplant relapse. Disclosures Nazha: MEI: Consultancy. Advani:Amgen: Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Consultancy; Glycomimetics: Consultancy. Carraway:Novartis: Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees; Balaxa: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; FibroGen: Consultancy; Jazz: Speakers Bureau; Agios: Consultancy, Speakers Bureau. Gerds:Celgene: Consultancy; Apexx Oncology: Consultancy; Incyte: Consultancy; CTI Biopharma: Consultancy. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees. Maciejewski:Apellis Pharmaceuticals: Consultancy; Alexion Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Apellis Pharmaceuticals: Consultancy; Ra Pharmaceuticals, Inc: Consultancy; Ra Pharmaceuticals, Inc: Consultancy; Alexion Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Majhail:Atara: Honoraria; Incyte: Honoraria; Anthem, Inc.: Consultancy.

Aim Autoantibodies have been implicated in the chronic rejection process after Lung Transplantation (LuT), but it is less certain if preformed non-HLA autoantibody (pAuAb) is the pre-LuT determinant for De Novo Donor Specific Antibody (dDSA) development. This study aims to investigate the relationship of pAuAb to dDSA fomation and the clinical impact of dDSA to LuT. Methods 124 recipients underwent LuT during 10/2012 −2/2014 at our center were retrospectively analyzed for dDSA (Mean Fluorescence Intensity ⩾1000). pAuAbs were detected among a subgroup of 118 patients using LABScreen™ Autoantibody (Thermofisher, panel coverage is listed in Table 1a). Cut-offs for pAuAbs were set up using 85% reference background values, which were calculated of lower than 85% population from a group of random selected non-transplanted and non-transfused individuals. Acute Cellular Rejection (ACR), Antibody Mediated Rejection (AMR) were recorded to assess LuT outcomes. Results 71 out of 124 (57%) recipients were identified with dDSA. Among dDSA recipients, Class I only, Class II only, and combined Class I and Class II were 16 (23%), 30 (42%), and 25 (35%), respectively. 53 (75%) of total dDSA was from DQ. pAuAbs to Angiotensinogen and Vimentin were clearly related to the formation of dDSA (p Conclusions The significant relevance of multiple pAuAbs to the formation of dDSA may provide a new perspective for evaluating the possibility of pAuAbs in eliciting dDSA at pre-LuT, which may help to reduce the risk of ACR and AMR related negative impact to LuT.

Killer immunoglobulin-like receptors (KIRs) expressed on natural killer and natural killer T cells are involved in activation of these cells and can influence antiviral immunity in the liver. This study investigated the association between KIR genetic diversity and sustained virologic response (SVR) to Peginterferon and Ribavirin (Peg/RBV) therapy in liver transplant (LT) recipients with hepatitis C virus (HCV) recurrence. We tested KIR genotypes in 44 HCV-infected LT recipients treated with Peg/RBV for 48 weeks. Patients were categorized as having KIR genotypes A/A or B/x and analyzed for association with SVR. Fifteen of 44 (34%) patients had SVR. Only 2 of 18 (11%) who lacked KIR2DS2/KIR2DL2 achieved SVR compared to 13 of 26 (50%) who carried these two genes (odds ratio: 8.0, 95% confidence interval: 1.5-42.0, P = 0.008). The association between lack of KIR2DS2/KIR2DL2 and SVR remained significant after exclusion of 10 patients with non-genotype 1 HCV. No correlation was found with other activating or inhibitory KIR genes. Absence of KIR2DS2 and/or KIR2DL2 is associated with failure of Peg/RBV therapy in patients with recurrent HCV after LT. These findings support the role of natural killer and natural killer T cells in HCV clearance after LT and might be generalizable to treatment of HCV infection outside the setting of LT.

Angiotensin II receptor sub-type 1 (AGTR1) plays an important role in the regulation of the cellular immune process. We hypothesized that recurrent acute rejection is associated with increased gene expression of AGTR1 in human heart transplantation.We identified a group of 14 heart transplant recipients who had recurrent acute cellular rejection (RAR), defined as three consecutive episodes of acute rejection (Gradeor =3A). These patients were matched to a control group (n = 15). mRNA gene expression of AGTR1 was measured in heart biopsy specimens of controls at 1 week post-transplant. AGTR1 mRNA was determined serially in the RAR group at baseline, each rejection episode, and after resolution of rejection. Angiotensin-converting enzyme (ACE) polymorphism was also evaluated.Both the control and RAR groups had similar mRNA AGTR1 expression at baseline. Compared with baseline, the RAR group had significantly increased mRNA expression of AGTR1 at the first episode of rejection (9-fold, p0.001), which increased further at the second episode (12-fold, p0.001) and peaked at the third episode (35-fold, p0.001). After resolution of rejection, AGTR1 expression was decreased significantly (p0.001), but remained elevated above baseline (6-fold, p0.001). No difference in ACE polymorphism was noted between the two groups. Compared with controls, the RAR patients had an increased incidence of hypertension, diabetes mellitus, chronic renal insufficiency and transplant vasculopathy during a mean follow-up period of 51.5 +/- 12 months.This is the first report to describe increased mRNA expression of AGTR1 in response to recurrent cellular rejection. Up-regulation of AGTR1 responds to treatment of rejection but not to complete recovery, a phenomenon that may potentially explain the link between rejection and subsequent clinical outcome.

Autoimmune sensorineural hearing loss (ASNHL) is the most common cause of sudden hearing loss in adults. Although autoimmune etiopathogenic events have long been suspected in ASNHL, inner ear-specific Ags capable of targeting T cell autoreactivity have not been identified in ASNHL. In this study, we show by ELISPOT analysis that compared with normal hearing age- and sex-matched control subjects, ASNHL patients have significantly higher frequencies of circulating T cells producing either IFN-γ (p = 0.0001) or IL-5 (p = 0.03) in response to recombinant human cochlin, the most abundant inner ear protein. In some patients, cochlin responsiveness involved both CD4+ and CD8+ T cells whereas other patients showed cochlin responsiveness confined to CD8+ T cells. ASNHL patients also showed significantly elevated cochlin-specific serum Ab titers compared with both normal hearing age- and sex-matched control subjects and patients with noise- and/or age-related hearing loss (p < 0.05 at all dilutions tested through 1/2048). Our study is the first to show T cell responsiveness to an inner ear-specific protein in ASNHL patients, and implicates cochlin as a prominent target Ag for mediating autoimmune inner ear inflammation and hearing loss.

Objective Management of acute Graft versus Host Disease (aGvHD) following liver transplant (LT) is critical for reducing mortality from this life-threatening disease. The aim of this study was to examine how Donor Lymphoid Chimerism (DLC) determinants associate with the diagnosis and prediction of clinical outcome of aGvHD after LT. Methods We retrospectively analyzed 17 LT patients (2007-2015) who were clinically suspected and DLC supportive of aGvHD. The DLC was tested by short tandem repeat with an initial 5% as positive cut off. The DLC determinants were: initial positive DLC after 30 days post-LT (InPD > 30D); initial positive DLCs in whole blood, T, NK, and CD8+ cells; peak DLCs of > 5% in whole blood, > 50% in each of T, NK, CD8+ cells respectively; positive DLC in both CD8+ and NK cells at initial phase, DLC 50% in both CD8+ and NK cells at peak phase. Clinical outcome was determined over the following 40-day duration of treatment and/or aGvHD related motility ( > 40D DuT/M). Logistic regression was used to analyze > 40D DuT/M in response to all the variables of DLC determinants. Results Of 17 aGvHD patients, the prevalence of 100% (16/16) in CD8+ cell was markedly higher than the prevalence of 41% (7/17) in whole blood, 59% (10/17), in T cell, and 38% (6/16) in NK cell at the initial detection of positive DLC. Amongst all analyzed variables of DLC determinants, InPD > 30D and DLC 50% in both CD8+ and NK cells at peak phase were all significantly associated with > 40D DuT/M. There was a mildly significant association with the individual variables of initial phase positive DLC in T and NK cells, and peak phase > 50% DLC in T and NK cells. Regardless of initial phase or peak phase, the individual variables of DLC in whole blood and CD8+ cell had no significant relationship with > 40D DuT/M (Figure 1). Conclusion Initial positive DLC of CD8+ cell is a sensitive and reliable indicator supporting the diagnosis of aGvHD. Both delayed diagnosis and/or peak phase DLC over 50% in both CD8+ and NK cells strongly predicts aGvHD related negative impact following LT. Download : Download full-size image

Background and Aims Early post-transplant hepatic fibrosis is associated with poor outcomes and may be influenced by donor/recipient genetic factors. The rs368234815 IFNL4 polymorphism is related to the previously described IL28B polymorphism, which predicts etiology-independent hepatic fibrosis. The aim of this study was to identify the impact of donor and/or recipient IFNL4 genotype on early fibrosis among patients transplanted for hepatitis C (HCV). Methods Clinical data were collected for 302 consecutive patients transplanted for HCV. 116 patients who had available liver biopsies and donor/recipient DNA were included. 28% of these patients with stage 2 fibrosis or greater were compared to patients without significant post-transplant fibrosis with respect to clinical features as well as donor/recipient IFNL4 genotype. Results The IFNL4 TT/TT genotype was found in 26.0% of recipients and 38.6% of donors. Patients who developed early post-transplant fibrosis had a 3.45 adjusted odds of having donor IFNL4 TT/TT genotype (p = 0.012). Donor IFNL4 TT/TT genotype also predicted decreased overall survival compared to non-TT/TT genotypes (p = 0.016). Conclusions Donor IFNL4 TT/TT genotype, a favorable predictor of spontaneous HCV clearance pre-transplant, is associated with increased early post-transplant fibrosis and decreased survival.

Objective It has been widely recognized that donor specific antibody (DSA) is correlated with antibody-mediated rejection (AMR) and graft loss in solid organ transplant (Tx). However, the impact of HLA-DP DSA in Tx has been poorly understood, especially in lung Tx. Here we analyze the association of DP DSA with lung Tx clinical outcomes. Methods This study retrospectively analyzed 213 individuals selected from 720 recipients who underwent lung Tx at Cleveland Clinic from 2008 to 2015. 213 patients were analyzed in three groups: G1- without HLA antibody (n = 144), G2- with DP antibodies (n = 69), G3- with DP DSAs among the individuals in G2 (n = 20). Two year graft survival (GS), AMR, acute cellular rejection (ACR), and bronchiolitis obliterans syndrome (BOS), were recorded as deleterious clinical outcomes. Luminex single antigen assay was used for HLA antibody testing. Results DP antibodies were detected in 10% (69/720) lung Tx patients. DP DSAs were identified in 29% (20/69) of the patients with DP antibodies. De novo DP DSA was identified in 90% (18/20) of the patients with DP DSAs. In G3, 15% (3/20) had other class I DSA, 35% (7/20) had other class II DSA, and 50% (10/20) had only DP DSAs. Compared to patients in G1, patients in G2 showed higher occurrence of AMR (p = 0.019), but there was no remarkable difference in 2 year graft survival, ACR, and BOS. A comparison between G1 and G3 showed that patients with DP DSAs (G3) presented with significantly more AMR and poor GS (p = 0.010 and 0.003 , respectively) than patients who had no HLA antibodies. However, ACR, and BOS were equivalent (Table 1a). There was higher incidence of AMR and lower rate of GS in patients with DP DSA combined with class I or class II than in patients who only had DP DSA (Table 1b). Download : Download high-res image (212KB) Download : Download full-size image Conclusion DP DSA is associated with negative impact following lung Tx by increasing the incidence of AMR and reducing GS. DP DSA combined with other HLA-DSAs demonstrates increased adverse clinical outcomes. This finding warrants further investigation with larger cohort studies.

Achievement of complete donor chimerism (CDC) after allogeneic nonmyeloablative hematopoietic stem cell transplantation (NMHSCT) is important for preventing graft rejection and for generating a graft-vs-malignancy effect. The alloreactivity of NK cells and some T-cell subsets is mediated through the interaction of their killer immunoglobulin-like receptors (KIRs) with target cell HLA/KIR ligands. The influence of KIR matching on the achievement of T-cell CDC after NMHSCT has not been previously described. We analyzed 31 patients undergoing T-cell replete related donor NMHSCT following fludarabine and 200 cGy TBI. Recipient inhibitory KIR genotype and donor HLA/KIR ligand matches were used to generate an inhibitory KIR score from 1 to 4 based upon the potential number of recipient inhibitory KIRs that could be engaged with donor HLA/KIR ligands. Patients with a score of 1 were less likely to achieve T-cell CDC (P=0.016) and more likely to develop graft rejection (P=0.011) than those with scores greater than 1. Thus, patients with lower inhibitory KIR scores may have more active anti-donor immune effector cells that may reduce donor chimerism. Conversely, patients with greater inhibitory KIR scores may have less active NK cell and T-cell populations, which may make them more likely to achieve CDC.

Many animal studies and studies on intermediate clinical endpoints have shown hormone replacement therapy (HRT) to be associated with both favourable and unfavourable cardiovascular effects. We reviewed the literature regarding HRT and the distinct endpoint of acute myocardial infarction (AMI) in peri- and postmenopausal women. Searches of the MEDLINE and EMBASE databases were conducted. Fifty papers were identified as eligible for inclusion: eight randomised controlled trials, 18 cohort studies, 23 case-control studies and one case-control and cohort study. The single large primary prevention randomised controlled trial on HRT and the risk of AMI in generally healthy women (Women’s Health Initiative trial) reported a small yet significantly increased risk of AMI in postmenopausal women receiving combined HRT. This contrasts with a large number of observational studies that suggested a protective effect, although in many of these studies the results were not statistically significant. Inconclusive evidence on the effect of duration of use does not support the notion that a possible protective association is causal. Detection bias and residual confounding are alternative explanations for the associations observed in the randomised controlled trial and observational studies. No studies on groups of women with existing cardiovascular disease or with diabetes mellitus, including the only large secondary prevention trial (Heart and Estrogen/Progestin Replacement Study), reported a significant change in AMI risk between HRT users and non-users. There is insufficient evidence to suggest that HRT is associated with a change in the risk of AMI in the majority of women. However, certain subgroups of women with specific genetic polymorphisms may be more susceptible to a change in the risk of AMI with HRT use.

Background NGS technologies have significant potential to generate high resolution HLA typing in a high throughput fashion. However, implementation in clinical immunogenetics laboratories involves extensive validation of a multitude of interdependent procedures, instruments, reagents, and software. To address these challenges we participated in March of 2014 in a multicenter Alpha study lead by the Immunogenetics Laboratory of a large academic institute that has developed an NGS-based protocol for HLA typing on the Illumina MiSeq. Methods We participated in the Alpha study with 2 main objectives: (1) validate the in-house developed NGS genotyping protocol for the HLA-A, B, C, DRB1 and DQB1 loci; (2) identify key critical steps in the protocol that we had problems with in our own lab prior NGS implementation. This abstract focuses only on key technical lessons learned from the study. The Alpha study results are independently submitted in another abstract. Results Participation in the Alpha study identified some critical steps in NGS workflow: (1) the quantitation of genomic DNA needs to be assessed by using methods that directly measure double stranded DNA concentration during primary sample preparation prior to target enrichment, (2) the library preparation reagents need to ensure adequate and uniform coverage throughout the length of the HLA targeted genomic region, (3) use appropriate methods for fragment size selection including magnetic beads and/or specialized electrophoretic instrumentation after library preparation, (4) quantitation and normalization of DNA of each amplicon to a standard DNA amount prior to amplicon pooling, (5) use two independent genotyping algorithms for data analysis to avoid systematic errors of genotype assignments caused by individual analysis software. Specific details about these lessons learned and more technical tips will be provided in this presentation. Conclusion In spite of the technical complexity of NGS workflow, identifying key critical steps in the process and identifying troubleshooting strategies are critical in implementing NGS in the clinical laboratories. Inter-laboratory validation studies and seeking the guidance from laboratories who developed NGS expertise is invaluable for expediting the learning curve for the implementation of this technology. M. Askar: Employee; Company/Organization; Cleveland Clinic.

Aim To present a highly sensitized patient with end stage renal disease who received his third kidney transplant from HLA-A, -B, -DR zero mismatched (0 MM) deceased donor (DD) and developed early acute cellular rejection (ACR – BANFF 2A) in absence of DSA. Methods Donor and recipient were HLA typed by RSSOP Luminex assay for HLA loci A, B and C, DRB1, DRB3/4/5, DQB1, DQA1, DPB1, and DPA1. HLA antibody identification were performed with One Lambda Luminex single antigen bead assay. Sera were tested untreated, treated with heat inactivation (HI) and 1:8 dilutions. CDC (with and without HI) and flow XM for T and B cells were tested at the day of transplant. Results A 40 years old man, highly sensitized (CPRA 100%) with a history of two previous renal transplants (lost due to non-immunological cause) with multiple class II DP antibodies with high MFI. The patient received a local zero mismatched donor was offered and with confirmatory testing an antigen level match for all HLA including DP. CDC and flow XM for T and B cells were negative. No DSA was detected pre or post-transplant. In post-operative day 1, the patient presented with anuria and hyperkalemia that mandated dialysis, and underwent dialysis throughout the rest of hospitalization as needed. Due to delayed graft function, he had a biopsy on post-operative day 8 that showed ACR – BANFF 2A – with negative C4d, peritubular capillaritis, and DSA. Treatment with anti-thymo globulin (ATG) did not show improvement. Consequently the patient received 3 sessions of plasmapheresis plus IvIG but the patient remained dialysis dependent. In post-operative day 50, biopsy showed chronic active T cell mediated rejection with no DSA. The graft remained non-functioning and graft nephrectomy was performed. This case suggests that highly sensitized kidney transplant candidates are at increased risk of cell mediated rejection and graft loss even in the context of 0 MM, negative DSA and flow crossmatch.

Send your letters to: The Editor, Child Care, St Jude’s Church, Dulwich Road, Herne Hill, London, SE24 0PB Fax: 020 7978 8319 email: childcare@markallengroup.com

Send your letters to: The Editor, Child Care, St Jude’s Church, Dulwich Road, Herne Hill, London, SE24 0PB Fax: 020 7978 8319 email: childcare@markallengroup.com

Abstract 4072 Donor immune effector cells including T and NK cells have been implicated in the development of GVHD after AHPCT. MICA is a ligand recognized by the activating receptor NKG2D that is expressed on the surface of NK, NKT, CD8+ and TCRγδ+ T cells. Allelic variants of MICA due to a single amino acid substitution at position 129 in the alpha2 domain have been reported to result in large differences in NKG2D binding. MICA alleles with a methionine (M) or valine (V) have been classified as having strong or weak binding affinity for NKG2D, respectively. It has been suggested that these variable affinities affect thresholds of NK cell triggering and T cell modulation. Homozygosity of V alleles (VV) has been associated with chronic GVHD (Boukouaci et al. Blood 2009;114:5216–5224). However, the effect of such polymorphisms on outcomes after RIC-AHPCT is not clear. We studied 31 patients (20 AML and 11 MDS) who had MRD RIC-AHPCT with fludarabine/low-dose TBI conditioning. All patients received peripheral blood stem cells and GVHD prophylaxis consisted of a calcineurin inhibitor and mycophenolate. Genotyping was performed retrospectively on patients' DNA samples by rSSOP to determine MICA 129 dimorphisms and they were then categorized as having VV (n=12), MV (n=17) or MM (n=2) dimorphisms. Post-transplant outcomes were compared between patients with VV (weak) vs. VM/MM (mixed/strong binding affinities). Outcomes were estimated using the cumulative incidence method and compared between groups with the Pepe-Mori test. Patients in the VV group had significantly less grade 3–4 acute GVHD (0 vs. 26%, respectively, p=0.022) and a trend to less chronic GVHD (8 vs. 37%, respectively, p=0.07) than the VM/MM group (see Figures). There were no differences between these groups regarding pre-transplant patient characteristics, CD34+/TNC doses, neutrophil or platelet engraftment, CMV/other infections, relapse, relapse mortality, non-relapse mortality, relapse-free or overall survival. We conclude that assessment of MICA gene polymorphisms in MRD RIC-AHPCT patients may have important implications for predicting GVHD. Those with a MICA dimorphism indicating weak binding affinity (VV) for the NKG2D activating receptor may have less alloreactive recipient immune effector cells that decrease the risk of developing GVHD. Further investigation of this observation with larger study populations is warranted. Disclosures: No relevant conflicts of interest to declare.

CMV remains the most common viral infection after AHSCT. NK and T cells provide protection against CMV reactivation. The interaction of inhibitory killer immunoglobulin-like receptors (KIRs) with target cell HLA class I molecules regulates NK cells and some T cell populations. Donor activating KIR genotype has been suggested to influence CMV reactivation after myeloablative AHSCT (Cook et al, Blood2006;107:1230–1232). However, the effect of donor activating or inhibitory KIR genotype on CMV reactivation after T-cell replete RIC AHSCT has not been reported. We analyzed 64 consecutive patients (pts) who underwent T-cell replete matched sibling donor RIC AHSCT at our institution from 1/16/00-4/24/07 with fludarabine and low-dose total body irradiation (200 cGy: 36 pts; 400 cGy: 28 pts). All pts received cyclosporine and mycophenolate mofetil for GVHD prophylaxis. CMV monitoring was performed by polymerase chain reaction testing. 49 (77%) pts were CMV seropositive or had a CMV seropositive donor; 25/49 (51%) had CMV reactivation post-AHSCT. 15 (23%) pts were CMV seronegative along with their donors and 1 (7%) of them had CMV reactivation. Donor activating KIR genotypes (KIR2DS1, KIR2DS2, KIR2DS3, KIR2DS4, KIR2DS5, KIR3DS1) and inhibitory genotypes (KIR2DL1, KIR2DL2, KIR2DL3, KIR3DL1, KIR3DL2) were determined by PCR-SSOP and/or PCR-SSP. Patient HLA KIR ligands including HLA-Cw groups C1 or C2, HLA-Bw4 and HLA-A3/11 (reviewed in Farag et al Blood2002; 100:1935–1947) and donor inhibitory KIR genotypes were analyzed. Missing patient KIR ligand was observed in 15 (23%) of the C1 group, 27 (42%) of the C2 group, 25 (39%) of the HLA-Bw4+ pts and 43 (67%) of the HLA-A3/11+ pts. There were no differences observed for CMV reactivation between any of these groups when comparing those with or without missing ligands. However, when the number of donor activating KIRs were considered a difference in CMV reactivation patterns was appreciated. Pts whose donor KIR genotype contained 5 or 6 activating KIR genes (N=16) had less CMV reactivation compared to those with only 1 to 4 activating KIR genes (N=48) (19% vs. 48%). This finding remained significant on multivariable analysis (p=0.038). No specific activating KIR was found to be associated with CMV reactivation. There were no differences between the groups (5–6 vs. 1–4 activating KIR genes) with regards to patient/donor CMV seropositivity, age, diagnoses, gender, race, number of prior chemotherapy regimens, prior radiation, time from diagnosis to RIC AHSCT, TBI dose, donor to patient gender, CD34+ and CD3+ cell doses. We conclude that donor activating KIR genotype influences CMV reactivation after matched sibling donor T-cell replete RIC AHSCT. These results may guide the selection of donors as well as identify patients who may benefit from closer CMV monitoring and additional strategies to prevent CMV reactivation post transplant. Figure Figure

Background: Anti B cell antibodies have been proposed as a treatment for post-transplant lymphoproliferative disorders (PTLD). Experience in children is limited. Methods and Results: We report experience (n=40) with use of the chimeric mouse/human antiCD20 monoclonal antibody (rituximab) in pediatric PTLD patients with refractory disease (no response to reduced immunosuppression, progressive or relapsed disease, or concomitant allograft rejection). Initial experience was through a voluntary registry (n=26), and most recent experience is from an onging prospective, non-randomized clinical trial (n=14). Use of chemotherapy or other experimental therapies were an exclusion criteria for both studies. All PTLD were of B cell origin and expressed CD20 and all but 2 (both in registry cohort) were EBV positive. The first cohort (registry) comprised 26 solid organ recipients from 12 centers (heart 11, kidney 6, lung 4, other 5) with mean age of 12.5 years, 29 months (range 2–132) from transplant. Histology revealed these lesions: polymorphic 17, monomorphic 7 (including 1 Burkitts-like), Hodgkins-like 1, unspecified 1. 21/26 received 375mg/m2 x 4 doses. There were no SAE’s. 18 pts (69%) showed CR, and 4 (16%) showed PR. The 4 non-responders comprised the 2 EBV negative cases, the Burkitts-like disease and the earliest onset case (fulminant disease at 2 months post-transplant). At latest follow-up (mean 41 months), 73% survive with one graft loss (kidney). In the prospective clinical trial, 14 patients (to date) with refractory disease were enrolled. The protocol comprises 4 doses of 375mg/m2 (weeks 1–4) with no further treatment for patients with CR or for those with no response. Patients with PR receive 4 further doses (weeks 5–8). The 14 patients were from 5 centers (lung 5, kidney 5, heart 4) with mean age of 6.5 years, 41 months (range 4–120) from transplant. Histology revealed the following: polymorphic 10, monomorphic 3, Hodgkin-like 1. There were no SAE’s. Two are still recieving therapy. Of the other 12, 9 (75%) acheived CR and 10 pts (83%) are alive with one graft loss (kidney) at mean follow-up of 1.5 years. The two deaths were due to fungal pneumonia and complications of elective surgery in a patient in CR (both lung recipients). Conclusions: These results suggest that rituximab may have an important role to play in management of refractory PTLD in solid organ recipients (CR rate approx. 70–75% with low incidence of graft loss). This group of patients traditionally has high mortality and has been treated with chemotherapy. Rituximab should be considered as first line treatment for refractory polymorphic PTLD in children after solid organ transplantation. Role in monomorphic disease requires further investigation. Use of rituximab as first line therapy is under investigation.