Aplastic anemia (AA) occurs when the bone marrow fails to support production of all three lineages of blood cells, which are necessary for tissue oxygenation, infection control, and hemostasis. The etiology of acquired AA is elusive in the vast majority of cases but involves exhaustion of hematopoietic stem cells (HSC), which are usually present in the bone marrow in a dormant state, and are responsible for lifelong production of all cells within the hematopoietic system. This destruction is immune mediated and the role of interferons remains incompletely characterized. Interferon gamma (IFNγ) has been associated with AA and type I IFNs (alpha and beta) are well documented to cause bone marrow aplasia during viral infection. In models of infection and inflammation, IFNγ activates HSCs to differentiate and impairs their ability to self-renew, ultimately leading to HSC exhaustion. Recent evidence demonstrating that IFNγ also impacts the HSC microenvironment or niche, raises new questions regarding how IFNγ impairs HSC function in AA. Immune activation can also elicit type I interferons, which may exert effects both distinct from and overlapping with IFNγ on HSCs. IFNα/β increase HSC proliferation in models of sterile inflammation induced by polyinosinic:polycytidylic acid and lead to BM aplasia during viral infection. Moreover, patients being treated with IFNα exhibit cytopenias, in part due to BM suppression. Herein, we review the current understanding of how interferons contribute to the pathogenesis of acquired AA, and we explore additional potential mechanisms by which interferons directly and indirectly impair HSCs. A comprehensive understanding of how interferons impact hematopoiesis is necessary in order to identify novel therapeutic approaches for treating AA patients.

With the World Health Organization (WHO) Global Initiative for Childhood Cancer, there is renewed interest in sustainable interventions to improve childhood cancer care in low-/middle-income countries (LMICs). Practitioners in LMICs have traditionally practiced "twinning," i.e., targeted international pediatric oncology partnerships (TIPPs) between one or more institutions in a high-income country (HIC) and an LMIC, to improve care for children with cancer in the latter. The International Society of Paediatric Oncology Committee for Paediatric Oncology in Developing Countries Working Group on Twinning, Collaboration, and Support reviewed guidelines from https: //cancerpointe.com and the current literature, gathered input from practitioners in LMICs, and in this article discuss the role of TIPPs in the WHO initiative.

We describe the case of a 3-year-old girl who developed veno-occlusive disease of the liver while receiving chemotherapy for parameningeal rhabdomyosarcoma. After suffering lethargy and oral mucosal bleeding for one day, the patient exhibited a sudden weight gain and refractoriness to platelet transfusions. Symptoms rapidly worsened with elevation of liver enzymes, bleeding diatheses, and respiratory failure. An ultrasound scan of the liver demonstrated reversed flow in the portal vein. Maximal supportive care, including tracheal intubation and mechanical ventilation, was required. The patient gradually recovered with no respiratory and minimal neurological sequelae. Veno-occlusive disease of the liver should be considered in children receiving chemotherapy who develop weight gain, a sudden drop in platelet count and derangement of liver enzymes. Aggressive supportive measures should be instituted if necessary, as patients surviving the acute phase can expect to make a full recovery.

No abstract

Advanced small cell carcinoma of the ovary (FIGO stage III or IV) is a rare and usually lethal tumor seen in adolescents and young women. In pediatric patients with advanced disease, there have been only two case reports of successful therapy, we report a third patient, diagnosed at 17 years of age, with an abdominal mass and metastatic disease to regional and distant lymph nodes, who was successfully treated with surgery and intensive multi-agent chemotherapy. Imatinib, thalidomide, and celecoxib were also administered for up to 24 months following initial chemotherapy. She remains in remission 3 years from diagnosis.

Dactinomycin-induced cutaneous toxicity is rare in pediatric patients not receiving radiation therapy. We describe dactinomycin-related lesions in the axilla, groin, and central line exit site of two children treated for rhabdomyosarcoma, neither of whom had received radiation treatment. One patient was initially treated with systemic antifungal therapy, and developed recurrent lesions on reexposure to the drug. The other was noted to have mild, diffuse hyperpigmentation. Skin biopsies revealed interface dermatitis with syringometaplasia in both cases. Both children recovered uneventfully within 4 weeks. Recognition of unusual rashes with a characteristic distribution in patients receiving dactinomycin should aid in diagnosis, and help avoid unnecessary therapeutic procedures.

No abstract

Mental status changes in an immunosuppressed child can be due to a variety of causes; aluminum toxicity is rarely considered. We report a teenage girl with acute lymphoblastic leukemia who developed mental status changes, speech disturbance, coarse tremor, and abnormal EEG findings following intravesical 1% alum irrigation and administration of aluminum-containing antacids. Her serum aluminurn levels were mildly elevated (14-22 pg/L, normal MI pg/ L), and bone marrow biopsy specimens demonstrated aluminum deposition on special staining (Krueger's method). All abnormalities resolved after a nine-week course of intravenous deferoxamine.0 1996 Wiley-Liss, Inc.