Indiscernible Benefit of Double-Unit Umbilical Cord Blood Transplantation in Children: A Single-Center Experience From Hong Kong.

Double-unit umbilical cord blood (DU-UCB) may extend the use of UCB transplantation and improve clinical outcomes. Data in the literature show that single-unit dominance happened in a vast majority of recipients, and the mechanism is unknown. We examined the clinical relevance and engraftment kinetics of DU-UCB transplant in 65 consecutive children who underwent unrelated single-unit (n = 25) and double-unit (n = 40) UCB transplantation for various hematological malignancies (n = 45) and nonmalignant disorders (n = 20). Our result showed no discernible benefit to children receiving double-unit transplant over those receiving single-unit transplant when the total nucleated cell (TNC) doses are ≥2.5 × 10(7)/kg, in terms of the hastening of the engraftment of neutrophils and platelets, reduction of nonengraftment, disease recurrence, early mortality, and graft-versus-host disease, despite significantly higher numbers of TNCs in double units. Further analyses demonstrated that the phenomena were not associated with underlying disease, duration of UCB storage, postthaw viability, HLA disparity, ABO incompatibility, gender, or doses of TNCs, CD34(+) cells, CD3(+) cells, or colony-forming units. Engrafting units in DU-UCB transplants were notably associated with higher CD34(+) cell dose. Chimerism studies demonstrated that single-unit dominance started before neutrophil engraftment in DU-UCB transplants. Data from the study suggested no advantage of infusing double-unit UCB, if an adequately dosed single-unit UCB is available. Successful prediction of the dominant graft would optimize algorithms of UCB selection and maximize the long-term engraftment of chosen units.

Vitamin D deficiency is associated with diagnosis and severity of childhood atopic dermatitis.

BACKGROUND: Recent studies implicated the importance of vitamin D in innate immune defense and pathogenesis of allergic diseases. However, the impact of vitamin D deficiency on atopic dermatitis (AD) diagnosis and severity remains unclear. This case-control study investigated such relationship in Hong Kong Chinese children. METHODS: Serum 25-hydroxyvitamin D [25(OH)D] levels of 498 AD children and 328 non-allergic controls were measured by immunoassay. Subjects were categorized into deficient (< 25 nm), insufficient (25-49.9 nm), and sufficient (≥ 50 nm) groups. Short-term and long-term AD severity was evaluated by physician-diagnosed SCORing Atopic Dermatitis (SCORAD) and Nottingham Eczema Severity Score (NESS), respectively. Atopy biomarkers were also measured for analysis. RESULTS: The mean (s.d.) serum 25(OH)D levels in AD patients and controls were 28.9 (15.3) and 34.2 (14.5) nm, respectively (p < 0.001). More patients had serum 25(OH)D levels <25 nm than controls (47.8% vs. 26.6%). AD severity as indicated by both SCORAD and NESS showed inverse associations with serum 25(OH)D levels (respective p = 3.6 × 10(-4) and 0.004 when adjusted for age, sex, month of assessment, and immunoassay batch as covariates). Vitamin D-deficient patients (3.08 ± 0.76) had higher logarithm-transformed total IgE than those with insufficient (2.74 ± 0.69) and sufficient (2.72 ± 0.72) serum 25(OH)D levels (p < 0.001). The proportion of subjects with elevated IgE was higher in vitamin D-deficient (43.2%) than vitamin D-sufficient (20.0%) groups. CONCLUSIONS: Vitamin D deficiency and insufficiency are prevalent in Hong Kong Chinese children. Vitamin D deficiency is associated with childhood AD and high total IgE. Serum 25(OH)D levels correlate inversely with both long- and short-term AD severity.