Post Transplant Lymphoproliferative Disorder risk factors in children: Analysis of a 23-year single-institutional experience.

INTRODUCTION: PTLD is the most frequent malignancy following SOT in children and the second most common SOT complication in adults. However, factors determining outcomes in children are poorly understood due to its relative rarity. METHODS: This study was performed at the University of Florida. Univariate and multivariate analyses were used to identify prognostic factors in pediatric patients diagnosed with PTLD. RESULTS: We reviewed records of 54 pediatric (younger than 18 years old at diagnosis) patients diagnosed with PTLD from 1994 to 2017. The median follow-up was 28.8 months. The estimated 5-year survival rate was 87.6% (95% CI 74.3-94.2%). Univariate analysis showed that organ transplanted (specifically heart transplant), poor response to initial treatment, allograft rejection, and low Karnofsky score were statistically significant for negative prognostic factors in determining survival. Multivariate analysis determined progression in response to initial treatment and presence of allograft rejection as statistically significant prognostic factors affecting overall survival. We found no statistically significant impact of EBV serological status on PTLD prognosis. CONCLUSIONS: Disease progression and allograft rejection were strong negative prognostic indicators in our study cohort. Close attention to graft status and development of therapies that protect the graft from rejection while bolstering anti-EBV immunity will be essential to further improving PTLD outcomes in children.

Detailed analysis of bone marrow from patients with ischemic heart disease and left ventricular dysfunction: BM CD34, CD11b, and clonogenic capacity as biomarkers for clinical outcomes.

RATIONALE: Bone marrow (BM) cell therapy for ischemic heart disease (IHD) has shown mixed results. Before the full potency of BM cell therapy can be realized, it is essential to understand the BM niche after acute myocardial infarction (AMI). OBJECTIVE: To study the BM composition in patients with IHD and severe left ventricular (LV) dysfunction. METHODS AND RESULTS: BM from 280 patients with IHD and LV dysfunction were analyzed for cell subsets by flow cytometry and colony assays. BM CD34(+) cell percentage was decreased 7 days after AMI (mean of 1.9% versus 2.3%-2.7% in other cohorts; P<0.05). BM-derived endothelial colonies were significantly decreased (P<0.05). Increased BM CD11b(+) cells associated with worse LV ejection fraction (LVEF) after AMI (P<0.05). Increased BM CD34(+) percentage associated with greater improvement in LVEF (+9.9% versus +2.3%; P=0.03, for patients with AMI and +6.6% versus -0.02%; P=0.021 for patients with chronic IHD). In addition, decreased BM CD34(+) percentage in patients with chronic IHD correlated with decrement in LVEF (-2.9% versus +0.7%; P=0.0355). CONCLUSIONS: In this study, we show a heterogeneous mixture of BM cell subsets, decreased endothelial colony capacity, a CD34+ cell nadir 7 days after AMI, a negative correlation between CD11b percentage and postinfarct LVEF, and positive correlation of CD34 percentage with change in LVEF after cell therapy. These results serve as a possible basis for the small clinical improvement seen in autologous BM cell therapy trials and support selection of potent cell subsets and reversal of comorbid BM impairment. CLINICAL TRIAL REGISTRATIONS URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00684021, NCT00684060, and NCT00824005.

Investigation of Complications Following Port Insertion in a Cancer Patient Population: A Retrospective Analysis.

Central venous access devices, specifically implantable ports, play an essential role in the care of oncology patients; however, complications are prevalent. This retrospective single-institutional review was performed to identify rates of complications from port placement and potential factors associated with these events. A retrospective analysis of 539 cancer patients who underwent port insertion between March 2016 and March 2017 at our institution was conducted. Data examining 18 potentially predictive factors were collected, and multivariate analysis was conducted using logistic regression and odds ratios (ORs) with standard errors to determine predictive factors. Out of 539 patients, 100 patients (19%) experienced 1 complication, and 12 patients (2%) experienced 2 or more complications. An overall lower rate of complications was seen in patients on therapeutic anticoagulation (OR: 0.17, P < .001) or on antiplatelet agents (OR: 0.47, P = .02). No patients on therapeutic anticoagulation developed venous thromboembolism (VTE; 0%). Right-sided port insertion was associated with decreased rates of infection (OR: 0.44, P = .04). Insertion as inpatient was associated with an increased risk for mechanical failure (OR: 4.60, P < .01). This analysis identified multiple predictive factors that can potentially put patients at a higher risk of experiencing complications following port insertion. Our data show lower rates of VTE for patients on anticoagulation or antiplatelet therapy. Further analysis is also necessary to determine why port insertion as an inpatient places patients at a higher risk of complications. This study highlights the risks associated with port placement and prompts the clinician to have an informed discussion with the patient weighing the risks and benefits.

Acute myeloid leukemia in the vascular niche.

The greatest challenge in treating acute myeloid leukemia (AML) is refractory disease. With approximately 60-80% of AML patients dying of relapsed disease, there is an urgent need to define and target mechanisms of drug resistance. Unfortunately, targeting cell-intrinsic resistance has failed to improve clinical outcomes in AML. Emerging data show that cell-extrinsic factors in the bone marrow microenvironment protect and support AML cells. The vascular niche, in particular, regulates AML cell survival and cell cycling by both paracrine secretion and adhesive contact with endothelial cells. Moreover, AML cells can functionally integrate within vascular endothelia, undergo quiescence, and resist cytotoxic chemotherapy. Together, these findings support the notion of blood vessels as sanctuary sites for AML. Therefore, vascular targeting agents may serve to remit AML. Several early phase clinical trials have tested anti-angiogenic agents, leukemia mobilizing agents, and vascular disrupting agents in AML patients. In general, these agents can be safely administered to AML patients and cardiovascular side effects were reported. Response rates to vascular targeting agents in AML have been modest; however, a majority of vascular targeting trials in AML are monotherapy in design and indiscriminate in patient recruitment. When considering the chemosensitizing effects of targeting the microenvironment, there is a strong rationale to build upon these early phase clinical trials and initiate phase IB/II trials of combination therapy where vascular targeting agents are positioned as priming agents for cytotoxic chemotherapy.

Chemosensitizing AML cells by targeting bone marrow endothelial cells.

Refractory disease is the greatest challenge in treating patients with acute myeloid leukemia (AML). Blood vessels may serve as sanctuary sites for AML. When AML cells were co-cultured with bone marrow endothelial cells (BMECs), a greater proportion of leukemia cells were in G0/G1. This led us to a strategy of targeting BMECs with tubulin-binding combretastatins, causing BMECs to lose their flat phenotype, degrade their cytoskeleton, cease growth, and impair migration despite unchanged BMEC viability and metabolism. Combretastatins also caused downregulation of BMEC adhesion molecules known to tether AML cells, including vascular cell adhesion molecule (VCAM)-1 and vascular endothelial (VE)-cadherin. When AML-BMEC co-cultures were treated with combretastatins, a significantly greater proportion of AML cells dislodged from BMECs and entered the G2/M cell cycle, suggesting enhanced susceptibility to cell cycle agents. Indeed, the combination of combretastatins and cytotoxic chemotherapy enhanced additive AML cell death. In vivo mice xenograft studies confirmed this finding by revealing complete AML regression after treatment with combretastatins and cytotoxic chemotherapy. Beyond highlighting the pathologic role of BMECs in the leukemia microenvironment as a protective reservoir of disease, these results support a new strategy for using vascular-targeting combretastatins in combination with cytotoxic chemotherapy to treat AML.