Impact of mother donor, peripheral blood stem cells and measurable residual disease on outcomes after haploidentical hematopoietic cell transplantation with post-transplant cyclophosphamide in children with acute leukaemia.

Haploidentical hematopoietic-cell transplantation using post-transplant cyclophosphamide(Haplo-PTCy) is a feasible procedure in children with haematologic malignancies. However, data of a large series of children with acute leukaemia(AL) in this setting is missing. We analysed 144 AL Haplo-PTCy paediatric recipients; median age was 10 years. Patients had acute lymphoblastic(ALL; n = 86) or myeloblastic leukaemia(AML; n = 58) and were transplanted in remission(CR1: n = 40; CR2: n = 57; CR3+: n = 27) or relapse (n = 20). Bone marrow was the graft source in 57%; donors were father (54%), mother (35%), or sibling (11%). Myeloablative conditioning was used in 87%. Median follow-up was 31 months. At day +100, cumulative incidence (CI) of neutrophil recovery and acute GVHD (II-IV) were 94% and 40%, respectively. At 2-years, CI of chronic GVHD and relapse, were 31%, 40%, and estimated 2-year overall survival (OS), leukaemia-free survival (LFS) and graft-versus-host-relapse-free survival (GRFS) were 52%, 44% and 34% respectively. For patients transplanted in remission, positive measurable residual disease (MRD) prior to transplant was associated with decreased LFS (p = 0.05) and GRFS (p = 0.003) and increased risk of relapse (p = 0.02). Mother donor was associated with increased risk of chronic GVHD (p = 0.001), decreased OS (p = 0.03) and GRFS (p = 0.004). Use of PBSC was associated with increased risk of chronic GVHD (p = 0.04). In conclusion, achieving MRD negativity pre-transplant, avoiding use of mother donors and PBSC as graft source may improve outcomes of Haplo-PTCy in children with AL.

PO-60 - Renal tumors with extensive vascular disease: management challenges in a pediatric series from the Hospital for Sick Children.

INTRODUCTION: Venous thrombotic events (VTE) are becoming more and more common in children, particularly in the hospital setting. To date, 1 in 200 children admitted to tertiary pediatric hospitals are now being recognized to develop VTE. Amongst those patients with an identified thrombotic occlusion, pediatric patients diagnosed with renal tumors have long been recognized, but their ideal management in the instances of vascular invasion remains controversial. AIM: We describe the clinical behavior of patients diagnosed with renal tumors and extra renal vascular involvement at The Hospital for Sick Children in Toronto, Canada. MATERIALS AND METHODS: A retrospective analysis was conducted in patients diagnosed from 1990 to 2012. Data collected included: age, gender, symptoms at presentation, staging, pathology report, radiological evidence of intravascular thrombus [i.e. renal veins (RV), inferior vena cava (IVC) and right atrium (RA)], intraoperative findings, therapeutic protocol implemented and anticoagulation; for outcomes, tumor and/or thrombus recurrence, thromboembolic phenomena [i.e. pulmonary embolism (PE)] and survival. RESULTS: Of 299 patients with renal tumors identified, 292 were included: Wilms (219), Renal Cell Carcinoma (RCC, 29), Clear Cell Sarcoma of the Kidney (CCSK, 12), others (32). The median age of the group was 4.53years (4days - 18 years). Extra renal vascular disease was identified in 29 patients, with a median age 7.05years (0.6-16 years; p=0.03), including Wilms tumors (22/219, 10%), RCC (2/29, 7%), CCSK (1/12, 8.3%) and others (4/32, 12.5%; p=0.01). Vascular involvement comprised exclusive evidence of RV disease (7), IVC disease (19; 15 infra-hepatic), RA disease (3) and PE (5).Treatment escalation because of vascular disease included neo-adjuvant chemotherapy (12; Wilms [11], RCC [1]), intraoperative cavectomy/ thrombectomy (1; Wilms), and cavotomies (11 Wilms [7], RCC [1], CCSK [1], PNET [1], sarcoma [1]). Four patients were placed under cardiopulmonary bypass. Anticoagulation was administered in 9/29 patients for their tumor-related thrombus, and one had a minor bleeding complications (oozing from the central venous line insertion site). CONCLUSIONS: Renal tumors with vascular invasion are a rare and challenging entity. Treatment included mostly cancer-related therapies and the role of vascular surgical approaches and/or systemic anticoagulation remains to be clarified.

Sequence change in the HS2-LCR and Gg-globin gene promoter region of sickle cell anemia patients

The fetal hemoglobin (HbF) levels and betaS-globin gene haplotypes of 125 sickle cell anemia patients from Brazil were investigated. We sequenced the Gg- and Ag-globin gene promoters and the DNase I-2 hypersensitive sites in the locus control regions (HS2-LCR) of patients with HbF level disparities as compared to their ßS haplotypes. Sixty-four (51.2 percent) patients had CAR/Ben genotype; 36 (28.8 percent) Ben/Ben; 18 (14.4 percent) CAR/CAR; 2 (1.6 percent) CAR/Atypical; 2 (1.6 percent) Ben/Cam; 1 (0.8 percent) CAR/Cam; 1 (0.8 percent) CAR/Arab-Indian, and 1 (0.8 percent) Sen/Atypical. The HS2-LCR sequence analyses demonstrated a c.-10.677G>A change in patients with the Ben haplotype and high HbF levels. The Gg gene promoter sequence analyses showed a c.-157T>C substitution shared by all patients, and a c.-222_-225del related to the Cam haplotype. These results identify new polymorphisms in the HS2-LCR and Gg-globin gene promoter. Further studies are required to determine the correlation between HbF synthesis and the clinical profile of sickle cell anemia patients.

ßS-Haplotypes in sickle cell anemia patients from Salvador, Bahia, Northeastern Brazil

ßS-Globin haplotypes were studied in 80 (160 ßS chromosomes) sickle cell disease patients from Salvador, Brazil, a city with a large population of African origin resulting from the slave trade from Western Africa, mainly from the Bay of Benin. Hematological and hemoglobin analyses were carried out by standard methods. The ßS-haplotypes were determined by PCR and dot-blot techniques. A total of 77 (48.1 percent) chromosomes were characterized as Central African Republic (CAR) haplotype, 73 (45.6 percent) as Benin (BEN), 1 (0.63 percent) as Senegal (SEN), and 9 (5.63 percent) as atypical (Atp). Genotype was CAR/CAR in 17 (21.3 percent) patients, BEN/BEN in 17 (21.3 percent), CAR/BEN in 37 (46.3 percent), BEN/SEN in 1 (1.25 percent), BEN/Atp in 1 (1.25 percent), CAR/Atp in 6 (7.5 percent), and Atp/Atp in 1 (1.25 percent). Hemoglobin concentrations and hematocrit values did not differ among genotype groups but were significantly higher in 25 patients presenting percent fetal hemoglobin ( percentHbF) > or = 10 percent (P = 0.002 and 0.003, respectively). The median HbF concentration was 7.54 ± 4.342 percent for the CAR/CAR genotype, 9.88 ± 3.558 percent for the BEN/BEN genotype, 8.146 ± 4.631 percent for the CAR/BEN genotype, and 4.180 ± 2.250 percent for the CAR/Atp genotype (P = 0.02), although 1 CAR/CAR individual presented an HbF concentration as high as 15 percent. In view of the ethnic and geographical origin of this population, we did not expect a Hardy-Weinberg equilibrium for CAR/CAR and BEN/BEN homozygous haplotypes and a high proportion of heterozygous CAR/BEN haplotypes since the State of Bahia historically received more slaves from Western Africa than from Central Africa