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The childhood obesity epidemic involves unusual and underrecognized complications associated with this clinical and public health problem. Obesity hypoventilation syndrome (OHS) is defined as the triad of obesity, daytime hypoventilation, and sleep-disordered breathing in the absence of an alternative neuromuscular, mechanical or metabolic explanation for hypoventilation. We herewith report a 12-year-old boy who was diagnosed with OHS. The patient improved with phlebotomy and bi-level positive airway pressure. To the best of our knowledge, this is the first reported case of secondary polycythemia due to OHS requiring therapeutic phlebotomy.

Acquired hemophilia A is a very rare, serious bleeding disorder. We describe a 5-year-old female who developed an acquired factor VIII inhibitor, and while under treatment with steroids, had an intestinal perforation with peritonitis and septic shock, making her a poor candidate for further immunosuppression. She was treated with rituximab with rapid, complete eradication of the inhibitor. She represents the first published case of a pediatric patient with acquired hemophilia A successfully treated with rituximab.

T-cell acute lymphoblastic leukemia (ALL) accounts for 15% of ALL cases in children and has been associated with a worse prognosis. Cytogenetic studies show an abnormal karyotype in 50-60% of the T-cell ALL patients; ABL1 fusions are present in approximately 8% of the cases. Dasatinib, a second-generation tyrosine kinase inhibitor, directly targets the BCR-ABL gene. We describe a pediatric case of T-cell ALL with amplification of the ABL1 gene in which remission was achieved only after the addition of dasatinib to conventional chemotherapy.

6580 Background: Advances in therapies have resulted in an overall complete remission rate of approximately 85% for childhood acute lymphoblastic leukemia (ALL). In contrast, the overall remission rate of adults with leukemia continues to be poor, only about 40% in cases of T cell-ALL (T-ALL). Therefore, it is imperative to generate new therapies that alone or in combination with other treatments could potentially increase the percentages of complete responders or be used to treat the refractory ALL population. Our published results show that a pegylated form of human arginase I (peg-Arg I) prevented T-ALL cell proliferation in vitro and in vivo through the induction of tumor cell apoptosis. Interestingly, the anti-leukemic effects induced by peg-Arg I did not affect the anti-tumor activity of normal T cells, suggesting an anti-tumor specific effect. Our hypothesis states that peg-Arg I has an anti-tumoral effect on B-ALL and T-ALL cells in vitro and that the sensitivity of ALL cells to peg-Arg I depends on their expression of argininosuccinate synthase (ASS) and their ability to produce L-arginine de novo from citrulline. Methods: Malignant T cell proliferation was tested using nonradioactive cell proliferation yellow tretrazolium salt kit. Apoptosis studies were based on the expression of annexin V. Western blot assays were conducted to determine enzymatic expression in different cell lines. Results: The results of our in vitro experiments showed that peg-Arg I had a pro-apoptotic and anti-proliferattive effect on B-ALL cells similar to the one previously seen on T-ALL cells. These effects can be overcome in cell lines able that express ASS and therefore to produce L-arginine de novo. Conclusions: Our results suggest the role of ASS in the ALL-apoptosis induced by peg-Arg-I. Our next steps include: _Understand why ASS-expressing ALL cells do not undergo apoptosis when cultured with peg-Arg-I_Determine the role of ASS in the anti-leukemic effect induced by peg-Arg-I in vivo. Completion of this research is expected to lead to a better understanding of how peg-Arg-I kills ALL cells and could provide the foundation for a novel therapy for ALL patients.

with promyelocytes 1%, myelocytes 5%, metamyelocytes 9%, stabs 4%, neutrophils 41%, monocytes 8%, eosinophils 1%, lymphocytes 29%, blasts cells 2%, normoblasts 3%, and platelets 70 £ 10 9 /L. The bone marrow examination showed increased cellularity, a moderate decrease in megakaryopoietic and erythropoietic systems, and hyperplasia of granulopoietic system with 1% blasts cells. The myeloid to erythroid ratio was 5,8:1. The same alterations were found in the bone marrow biopsy. Myelo® brosis was not observed. The fetal hemoglobin was 9,2%, A2 hemoglobin 2,6%. The molecular study did not reveal the ber-abl rearrangement by PCR. The Epstein Barr virus serological studies were negative. The cell culture with Pike method 3 showed spontaneous granulocyte/macrophage colonies growth and an abnormal increase pattern of the same line when calf bovine serum was added to the medium [3]. One month later the WBC was 44.9 £ 10 9 /L, the hemoglobin fell to 7.4 g/dL, and a red cell transfusion was administered. The child received treatment with mercaptopurine at 60 mg/m 2 daily for 9 months. No changes in the clinical symptoms, physical ® ndings, or