Treatment of relapse after allogeneic stem cell transplantation in children and adolescents with ALL: the Frankfurt experience.

Therapy for post-transplant relapse of paediatric ALL is limited. Standardised curative approaches are not available. We hereby describe our local procedure in this life-threatening situation. A total of 101 ALL patients received their first allogeneic stem cell transplantation (SCT) in our institution. After relapse, our primary therapeutic goal was to cure the patient with high-dose chemotherapy or specific immunotherapy (HDCHT/SIT) followed by a second SCT from a haploidentical donor (transplant approach). If this was not feasible, low-dose chemotherapy and donor lymphocyte infusions (LDCHT+DLI) were offered (non-transplant approach). A total of 23 patients suffered a post-transplant relapse. Eight patients received HDCHT/SIT, followed by haploidentical SCT in 7/8. Ten received LDCHT+DLI. The eight patients treated with a second transplant and the ten treated with the non-transplant approach had a 4-year overall survival of 56% and 40%, respectively (P=0.232). Prerequisites for successful treatment of post-transplant relapse by either a second transplant or experimental non-transplant approaches are good clinical condition and the capacity to achieve haematological remission by the induction treatment element.

Percentiles of Lymphocyte Subsets in Preterm Infants According to Gestational Age Compared to Children and Adolescents.

Preterm newborns show an increased susceptibility to infections, conceivably related to their immature immune system. To gain further knowledge about the immune development in early preterm infants, we aimed to establish references for lymphocyte subsets and compare the maturation process during hospitalization to healthy term-born children and adolescents. For this purpose, peripheral blood samples (n = 153) were collected from 40 preterm infants, gestational age (GA) 26-30 week between 2nd and 6th day of life, and were monitored in intervals of every 2 or rather 4 weeks until the end of hospitalization. Furthermore, we analysed single sample controls of 10 term neonates. We compared these data with results of a study in healthy children and adolescent (n = 176). Flow cytometry of immune cell subsets was performed as single-platform analysis using 10-colour flow cytometry. Based on preterm's age, our percentile model allows readout of absolute cell count for lymphocytes, B cells, T cells, NK cells, T8 and T4 cells. The median (minimum) value of T-, B- and NK cells after birth was 2800 (600), 790 (120) and 140 (20) cells/µl, respectively. Major differences were found in absolute cell numbers of B cells, and in the frequency of regulatory T cells, most pronounced in the earliest preterm infants (GA 26). Compared to healthy children and adolescents, preterm infants reached lymphocyte counts in between the 5th and 50th percentile when discharging the hospital. This prospective observational study provides reference percentiles for lymphocytes subsets of preterm infants. These data are conducive to interpret immunological capability of preterm infants with possible immune disorders appropriate.

Age-matched dendritic cell subpopulations reference values in childhood.

Dendritic cells (DCs) are the most potent antigen-presenting cells and are the key link between the innate and adaptive immune response. Only a few reports with study populations of up to 50 individuals have been published with age-based reference values for DC subpopulations in healthy children. Therefore, we aimed to establish reference ranges in a larger study population of 100 healthy children, which allowed age-matched subgroups. Most previous studies were performed using a dual-platform approach. In this study, a single-platform approach in a lyse no-wash procedure was used. DC subpopulations were defined as follows: CD45(+) CD85k(+) HLA-DR(+) CD14(-) CD16(-) CD33(+) cells as myeloid DCs (mDCs) and CD45(+) CD85k(+) HLA-DR(+) CD14(-) CD16(-) CD123(+) cells as plasmacytoid DCs (pDCs). Reference ranges were established using a semi-parametric regression of age-matched absolute and relative DC counts. We found a significant decline with increasing age in the medians of mDCs (P = 0.0003) and pDCs per µl peripheral blood (PB) (P = 0.004) and in the 50%, 90% and 95% reference ranges. We also identified significantly lower absolute cell counts of mDCs per µl PB in girls than in boys for all age groups (P = 0.0015). Due to the larger paediatric study population and single-platform approach, this study may give a more precise overview of the normal age-matched development of DC subpopulations and may provide a basis for analyzing abnormal DC counts in different illnesses or therapies such as post stem cell transplantation.