Peripheral blood as a stem cell source for hematopoietic cell transplantation in children: is the effort in vein?

Catching Them Early: Framework Parameters and Progress for Prenatal and Childhood Application of Advanced Therapies

Advanced therapy medicinal products (ATMPs) are medicines for human use based on genes, cells or tissue engineering. After clear successes in adults, the nascent technology now sees increasing pediatric application. For many still untreatable disorders with pre- or perinatal onset, timely intervention is simply indispensable; thus, prenatal and pediatric applications of ATMPs hold great promise for curative treatments. Moreover, for most inherited disorders, early ATMP application may substantially improve efficiency, economy and accessibility compared with application in adults. Vindicating this notion, initial data for cell-based ATMPs show better cell yields, success rates and corrections of disease parameters for younger patients, in addition to reduced overall cell and vector requirements, illustrating that early application may resolve key obstacles to the widespread application of ATMPs for inherited disorders. Here, we provide a selective review of the latest ATMP developments for prenatal, perinatal and pediatric use, with special emphasis on its comparison with ATMPs for adults. Taken together, we provide a perspective on the enormous potential and key framework parameters of clinical prenatal and pediatric ATMP application.

Stem cell source and outcome after hematopoietic stem cell transplantation (HSCT) in children and adolescents with acute leukemia

Allogeneic hematopoietic stem cell transplantation from siblings, unrelated donors or HLA mismatched family members has become an important procedure to offer a chance of cure to children and adolescents with acute leukemia at high risk of relapse and those with certain genetic diseases. Bone marrow (BM) was the only stem cell source for many years. During the past 15 years, peripheral blood stem cells from granulocyte colony-stimulating factor (G-CSF) mobilized healthy donors, or umbilical cord blood from related or unrelated donors, have become available. Each stem cell source has different risks/benefits for patients and donors, the choice depending not only on availability, but also on HLA compatibility and urgency of the HSCT. This review will analyze the advantages and limitations of each of these options, and the main criteria which can be applied when choosing the appropriate stem cell source for pediatric transplant recipients with acute leukemia.

Wireless capsule endoscopy for diagnosis of acute intestinal graft-versus-host disease

BACKGROUND

The small intestine is the most common location of intestinal graft-versus-host disease (GVHD). EGD with duodenal biopsies yields the highest diagnostic sensitivity, but the jejunum and ileum are not accessible by regular endoscopy. In contrast, wireless capsule endoscopy (WCE) is a noninvasive imaging procedure offering complete evaluation of the small intestine.

OBJECTIVE

The objective was to compare the diagnostic value of EGD, including biopsies, with the results of WCE in patients with acute intestinal symptoms who received allogeneic blood stem cell transplantation and to analyze the appearance and distribution of acute intestinal GVHD lesions in these patients.

DESIGN

An investigator-blinded, single-center prospective study.

PATIENTS

Patients with acute intestinal symptoms after allogeneic stem cell transplantation underwent both EGD and WCE within 24 hours. Clinical data were recorded during 2 months of follow-up.

RESULTS

Fourteen consecutive patients with clinical symptoms of acute intestinal GVHD were recruited. In 1 patient, the capsule remained in the stomach and was removed endoscopically. In 7 of 13 patients who could be evaluated, acute intestinal GVHD was diagnosed by EGD with biopsies, but 3 of these would have been missed by EGD alone. In all 7 patients with histologically confirmed acute intestinal GVHD, WCE revealed typical signs of GVHD. Lesions were scattered throughout the small intestine, but were most accentuated in the ileum.

LIMITATIONS

This study had a small number of patients.

CONCLUSIONS

WCE, which is less invasive than EGD with biopsies, showed a comparable sensitivity and a high negative predictive value for diagnosing acute intestinal GVHD. It may be helpful to avoid repeated endoscopic procedures in patients who have undergone stem cell transplantation.

Hematopoietic stem cell donation in children: a review of the sibling donor experience

Hematopoietic Stem Cell Transplant (HSCT) represents the second most frequent major organ transplant in the United States. Compared with other family members, siblings are more likely to be immunologically matched with the recipient and therefore are often the most suitable donors. Due to a dearth of information on the positive and adverse effects of HSCT on pediatric sibling donors, we sought to examine available data. Eight published reports assessing the pediatric sibling donor experience were identified in the literature. Studies were predominately small (n < 44) and cross-sectional. Results suggest a range of psychological distress responses with higher distress in pediatric donor than non-donor siblings. Recommendations include future longitudinal research on sibling donor psychosocial adjustment, identification of sibling donors at high risk for maladaptive responses, and development of educational and psychosocial interventions for this overlooked pediatric population.

Safety and efficacy of allogeneic PBSC collection in normal pediatric donors: The Pediatric Blood and Marrow Transplant Consortium Experience (PBMTC) 1996–2003

The use of peripheral blood stem cells (PBSC) for allogeneic transplants in adults has greatly increased. This trend is reflected in pediatrics, where healthy children increasingly are donating PBSC or donor lymphocyte infusion (DLI) via apheresis for use by ill siblings. There is a potential concern that the risks of PBSC collection may differ for pediatric donors. However, no large studies have assessed safety issues in this population. To address this need, we reviewed 218 (213 PBSC, five DLI) collections in 201 normal pediatric donors (8 months to 17 years, median 11.8 years) at 22 institutions in the Pediatric Blood and Marrow Transplant Consortium. Donors received a median of 4 days of growth factor, and mean collection yield was 9.1 x 10(6) CD34+ cells/kg recipient weight. Younger age, days of apheresis, and male gender predicted increased yield of CD34+ cells/kg donor weight. Growth factor-induced pain was mild and reported in less than 15% of patients. Most donors <20 kg (23/25, 92%) required PRBC priming of the apheresis machine. This experience with over 200 collections demonstrates that PBSC collection is safe in normal pediatric donors and desired CD34 cell yields are easily achieved. Younger children utilize more medical resources and children <20 kg usually require a single blood product exposure.