Optimized peripheral blood progenitor cell mobilization for autologous hematopoietic cell transplantation in children with high-risk and refractory malignancies.

BACKGROUND: Autologous hematopoietic stem cell transplantation (aHSCT) using hematopoietic progenitor cells (HPCs) has become an important therapeutic modality for patients with high-risk malignancies. Current literature on standardized method for HPC apheresis in children is sparse and failure rate reported as high as 30%. PATIENTS/METHODS: A retrospective study of 125 pediatric patients with high-risk malignancies undergoing aHSCT in Western Australia between 1997 and 2016 was conducted. RESULTS: Mobilization was achieved by means of chemotherapy and granulocyte colony-stimulating factor (G-CSF). Patients underwent apheresis the day after CD34+ counts reached ≥20/µL and an additional dose of G-CSF. Peripheral arterial and intravenous lines were inserted in pediatric intensive care unit under local anesthetic and/or sedation, omitting the need for general anesthesia as well as facilitating an uninterrupted apheresis flow. Larger apheresis total blood volumes were processed in patients weighing ≤20 kg. The minimal dose of ≥2 × 106 CD34+ cells/kg was successfully collected in 98.4% of all patients. The optimal dose of 3-5 × 106 CD34+ cells/kg was collected in 96% of patients scheduled for a single aHSCT, 87.5% for tandem, and 100% for triple aHSCT. All HPC collections were completed in one apheresis session. Mobilization after ≤3 chemotherapy cycles and cycles including cyclophosphamide resulted in a significantly higher yield of CD34+ cells. CONCLUSION: Our approach to HPC mobilization by means of chemotherapy and single myeloid growth factor combined with optimal collection timing facilitated by continuous apheresis flow resulted in highly effective HPC harvest in children and adolescents with high-risk cancers.

Vaccine-preventable disease following allogeneic haematopoietic stem cell transplant in Western Australia.

AIM: Infection is an important and frequent cause of mortality and morbidity following allogeneic haematopoietic stem cell transplantation (HSCT). This study was conducted to determine the epidemiology and clinical phenotype of vaccine-preventable disease in children who have undergone HSCT following the implementation of a standard revaccination programme. METHODS: Children receiving first allogeneic HSCT in Western Australia between January 2005 and December 2014 were eligible for recruitment. Patients received standard antimicrobial prophylaxis and were vaccinated according to the West Australian post-HSCT immunisation schedule, commencing 6 months following HSCT. Children who developed any illness post-HSCT were reviewed, and investigations for infectious disease were undertaken as clinically indicated. Positive identification of vaccine-preventable disease was documented with the clinical course of the illness. RESULTS: A total of 71 patients were enrolled in the study. The overall incidence of vaccine-preventable disease following HSCT was 19.7%; influenza accounted for 50% of all cases, herpes zoster for 42.9%. All episodes occurred late, beyond day 100 post-HSCT. Overall survival for matched-sibling donor transplants was 83.3 and 75.0% at 1 and 5 years, respectively, and was 72.3 and 63.3% for alternative donor transplants. Mortality due to vaccine-preventable disease was low, with one death from disseminated herpes zoster. CONCLUSIONS: There is a high incidence of vaccine-preventable morbidity post-allogeneic HSCT in West Australian children. Viral aetiology constitutes the main burden, namely, influenza infection and varicella zoster virus reactivation. Further efforts are required to identify the most appropriate preventative strategies.

Automated enumeration of lymphoid and plasma cells in bone marrow to establish normal reference ranges.

AIMS: The number of precursor and mature lymphoid cells and plasma cells in normal bone marrow trephine (BMT) biopsies throughout the human lifespan is unknown. Reference ranges have been established from aspirated marrow, but due to haemodilution errors, these do not accurately reflect the native marrow milieu. We aimed to define age-specific, normal reference ranges for lymphoid and plasma cells in BMT biopsy specimens using a combined immunophenotyping and digital enumeration approach. METHODS: Morphologically normal BMT biopsy specimens (n=483) were obtained from patients aged 1 month to 90 years of age. Immunohistochemistry was performed to identify lymphoid progenitors , T-lymphocytes (CD3), B-lymphocytes (CD20) and plasma cells (CD138 and MUM1). Positive cells were counted using digital enumeration software, and the percent positivity for each antigen was determined per case. Mean values were generated for specific age groups, and age-defined reference ranges were determined for each antigen using normalised data. RESULTS: A mean of 16 609 cells (range: 7210-34 097) were counted per biopsy. Infant marrows showed a predominance of immature lymphoid progenitors and B cells. With increasing age, an increase in mean T cell and plasma cell numbers were observed. The results showed the same trends to flow cytometry references for aspirate material although the absolute values differed. CONCLUSIONS: Combined immunohistochemistry and automated enumeration gives an accurate, reproducible number of antigen-positive cells and has generated normal reference ranges for these cell types in BMT biopsies. The method and ranges we have established have the potential to be applied in routine clinical practice.

Haemopoietic stem cell transplantation for children in Australia and New Zealand, 1998-2006: a report on behalf of the Australasian Bone Marrow Transplant Recipient Registry and the Australian and New Zealand Children's Haematology Oncology Group.

OBJECTIVE: To document haemopoietic stem cell transplantation (HSCT) activity and trends among paediatric patients in Australia and New Zealand. DESIGN, SETTING AND PARTICIPANTS: A retrospective analysis of data reported to the Australasian Bone Marrow Transplant Recipient Registry by the seven paediatric HSCT institutions in Australia and New Zealand over the 9-year period 1998-2006, with particular focus on the most recent years (2002-2006). MAIN OUTCOME MEASURES: Types of HSCT performed; transplant-related mortality (TRM); stem cell sources; indications for HSCT; causes of death after HSCT. RESULTS: Over the period 1998-2006, 522 autologous HSCT procedures (41%) and 737 allogeneic procedures (59%) were performed. About 60% of allogeneic transplants involved alternative donors (donors other than a human leukocyte antigen-matched sibling). The use of umbilical cord blood as a source of haemopoietic stem cells has doubled since 1998, with 34% of allogeneic transplants in 2006 using cord blood. Over the period 2002-2006, the median age of patients receiving transplants was 7 years (range, 0-19 years). The most common indications for allogeneic HSCT were acute lymphoblastic leukaemia (33%) and acute myeloid leukaemia (24%). The most common indications for autologous HSCT were neuroblastoma (23%), medulloblastoma (21%) and Ewing sarcoma (10%). TRM at 1 year after transplant was 22% for alternative donor transplants, 7% for matched-sibling transplants and 5% for autologous transplants. Relapse or persistence of a child's underlying condition accounted for 54% of all deaths within 1 year after transplant. CONCLUSIONS: HSCT is an important procedure for children with a range of life-threatening illnesses. Local trends in the indications for HSCT, donor selection and TRM reflect contemporary international practice.

Few differences in diet and health behaviors and perceptions were observed in adult urban Native American Indians by tribal association, gender, and age grouping.

Diet and health behaviors and perceptions of adult urban Native American Indians in a large Midwestern city were evaluated for differences by tribal association, gender, and age grouping. The hypothesis was that human behavior is influenced by tribal association, gender, and age grouping in the subject population. The subjects included 33 men and 32 women, with 26 being Sioux; 22 Omaha; and 17 a combination of other tribes. The descriptive survey included two interviewer-administered 24-hour recalls. The majority of subjects were overweight or obese. Significant differences (P< .05) were observed in vitamin A and calcium intakes by tribal association. Men reported consuming significantly more (P< .05) kilocalories, vitamin C, and sodium. Over half the subjects consumed more than the recommended 20% to 35% kcal from fat, >or=10% kcal from saturated fat, and >or=300 mg cholesterol/d. Less than Estimated Average Requirements for vitamin A, vitamin C, and iron were consumed by 31%, 59%, and 6%, respectively; 79% consumed less than Adequate Intakes for calcium. Ninety-two percent consumed more than the Tolerable Upper Intake Level for sodium. Few differences were observed in the kilocalorie, vitamin A, vitamin C, calcium, and sodium intakes of these Native American Indians by tribal association, gender, or age grouping. Significant differences in percentages consuming alcohol were observed by gender (P< .05) and by age grouping (P< .01). A significant difference (P< .01) was observed by gender regarding the subjects' perceptions of their being alcoholics. Overall, few differences were observed in diet and health behaviors and perceptions of adult urban Native American Indians by tribal association, gender, and age grouping.

Deletion of one copy of the p16INK4A tumor suppressor gene is implicated as a predisposing factor in pediatric leukemia.

The p16INK4A tumor suppressor gene is frequently disrupted by mutation or deletion in a wide range of cancer types, ranging from leukemia to cancers of the bladder, skin, lung, liver, and spleen. We have previously shown that deletion of at least one copy of the p16INK4A gene is associated with an increased risk of relapse in pediatric leukemia. Our data suggest that hemizygous p16INK4A deletion may be constitutional, conferring susceptibility to leukemia. Confirmation of this association is worthy of a larger study. Data from primary leukemia specimens are also presented here which examined the possibility that the remaining allele of the gene was inactivated by another mechanism such as mutation or was silenced by methylation. These possibilities were formally excluded in a case of hemizygous loss of the p16INK4A gene in leukemia, establishing that in this case the p16INK4A deletion was either semidominant or fully haploinsufficient for relapse susceptibility in this disease. Implementation of high throughput methods such as those used here for detecting hemizygous loss of tumor suppressor genes will become increasingly important for molecular diagnosis of cancer. This is particularly true for the emerging class of tumor suppressor genes where deletion of one allele is sufficient to confer cancer susceptibility or poor prognosis with standard treatment.