Human leukocyte antigen evolutionary divergence influences outcomes of paediatric patients and young adults affected by malignant disorders given allogeneic haematopoietic stem cell transplantation from unrelated donors.

High genetic heterogeneity in the human leukocyte antigen (HLA) increases the likelihood of efficient immune response to pathogens and tumours. As measure of HLA diversity, HLA evolutionary divergence (HED) has been shown to predict the response of tumours to immunotherapy and haematopoietic stem cell transplantation (HSCT) in adults. We retrospectively investigated the association of HED with outcomes of 153 paediatric/young adults patients, treated for malignant disorders with HSCT from 9-10/10 HLA-matched unrelated donors. HED was calculated as pairwise genetic distance between alleles in patient HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1, using the locus median to stratify patients with 'high' or 'low' HED. Patients with high HED-B and -DRB1 showed significantly improved disease-free survival (DFS), especially when combined (70.8% vs 53.7% p = 0.008). High HED-B + -DRB1 was also associated with improved overall survival (OS) (82.1 vs 66.4% p = 0.014), and concomitant reduction of non-relapse-mortality (5.1% vs 21.1% p = 0.006). The impact on OS and DFS of combined HED-B + -DRB1 was confirmed in multivariate analysis [hazard ratio (HR) 0.39, p = 0.009; and HR 0.45, p = 0.007 respectively]. Only high HED scores for HLA-DPB1 were associated, in univariate analysis, with reduced incidence of relapse (15.9% vs 31.1%, p = 0.03). These results support HED as prognostic marker in allogeneic HSCT and, if confirmed in larger cohorts, would allow its use to inform clinical risk and potentially influence clinical practice.

Higher growth, fat and fat-free masses correlate with larger cerebellar volumes in preterm infants at term.

AIM: Smaller cerebellar volumes in very low-birthweight (VLBW) infants at term have been related to adverse cognitive outcomes, and this study evaluated whether these volumes were associated with a growth in body composition during hospital stays. METHODS: We prospectively recruited 42 VLBW infants from an Italian neonatal unit between January 2013 and August 2015. Cerebellar volumes and body composition were measured by magnetic resonance imaging (MRI) and air-displacement plethysmography, respectively, at 40 weeks of gestational age and anthropometric and nutritional data were collected. We also included 20 term-born controls. RESULTS: The mean gestational age and birthweight of the VLBW infants were 29.4 (±1.9) weeks and 1120 (±290) g. There was a positive correlation between cerebellar volumes and daily weight gain from birth to term (R2 = 0.26, p = 0.001), weight (R2 = 0.25, p = 0.001), length (R2 = 0.16, p = 0.01), fat mass (R2 = 0.15, p = 0.01) and fat-free mass at term (R2 = 0.20, p = 0.003). In multiple regression analysis, daily weight gain, mechanical ventilation and postconceptional age at MRI were independently associated with cerebellar volumes. Anthropometric data and cerebellar volumes were similar between VLBW and control infants. CONCLUSION: Higher growth, higher fat mass and fat-free mass were associated with larger cerebellar volumes in VLBW infants at term.

Hematopoietic stem cell transplantation-induced bone remodeling in autosomal recessive osteopetrosis: Interaction between skeleton and hematopoietic and sensory nervous systems.

OBJECTIVE: Autosomal recessive osteopetrosis (ARO) is a rare congenital disorder of defective bone resorption. The inability of osteoclasts to resorb bone compromises the development of bone marrow cavity, and ultimately, leads to defective hematopoiesis and death within the first decade. The only curative treatment currently available for certain forms of ARO is hematopoietic stem cell transplantation (HSCT). Infants over ten months of age suffering from ARO are defined as patients with advanced disease; HSCT to these patients is associated with high risk of transplant-related mortality (TRM). Because of the extreme variability of ARO clinical phenotypes, the most reliable predictive factor of TRM and graft failure risk is the residual bone marrow space volume. CASE REPORT: We report clinical and radiological outcomes of one patient affected by ARO and treated with HSCT at advance stage of the disease. We describe the anomalies in various tissues, including bone marrow and bones at the moment of the diagnosis and document their gradual disappearance after HSCT until their complete resolution based on magnetic resonance imaging (MRI) observations. We provided radiological images of the cranial vault bone structure modifications, correlating the radiological appearance of the optical canals and nerves and of the cerebellum with the neurological manifestations of the disease. CONCLUSIONS: Our results demonstrate that MRI is a highly sensitive technique that provides excellent images of bone marrow space before and after HSCT without exposing children to ionizing radiation. MRI also permits us to evaluate post-transplant skeletal remodeling and the deriving changes in the hematopoietic and sensory system.

Parasitic Hypereosinophilia in Childhood: a Diagnostic Challenge.

Severe hypereosinophilia (HE) in children is rare, and its etiological diagnosis is challenging. We describe a case of a 30-month-old boy, living in a rural area, who was admitted to our Clinic with a 7-day history of fever and severe hypereosinophilia. A comprehensive diagnostic workup could not identify the cause of this condition. On day 6, the rapidly increasing eosinophil count (maximum value of 56,000/mm3), the risk of developing hypereosinophilic syndrome, and the patient's history prompted us to undertake an empiric treatment with albendazole. The eosinophil count progressively decreased following treatment. On day 13, clinical condition and hematological data were satisfactory, therefore the treatment was discontinued, and the patient was discharged. Three months later, anti-nematode IgG antibodies were detected in patient serum, thus establishing the etiological diagnosis. In conclusion, an empiric anthelmintic treatment seems to be justified when parasitic hypereosinophilia is strongly suspected, and other causes have been excluded.

Total body irradiation and iron chelation treatment are associated with pancreatic injury following pediatric hematopoietic stem cell transplantation.

Whereas many studies have addressed the risk of organ dysfunction following hematopoietic stem cell transplantation (HSCT), little is known about pancreatic susceptibility in this setting. We aimed to investigate the effect of iron overload (IO) and total body irradiation (TBI) on pancreatic function of children undergoing HSCT. We retrospectively evaluated children admitted between 2012-2016 fulfilling the following criteria: normal pancreatic iron concentration (PIC), regular pancreatic function before HSCT, availability of abdominal magnetic resonance imaging with gradient-recalled-echo sequences and a full set of biochemical markers of IO and pancreatic function performed before HSCT and at discharge. We divided the patients according to the use of TBI or myeloablative chemotherapy (MCHT) in the conditioning regimen. All patients with severe IO or moderate IO with a high risk of engraftment delay or transplantation-related complications underwent chelation therapy with deferoxamine (DFO) from the first day of conditioning to discharge. 63 patients had a HSCT in the study period, 13 did not fulfill the inclusion criteria; 50 (25 in each group) are included in the analysis, and did not show differences at baseline evaluation. At follow up testing the TBI group showed a significantly higher PIC (107,8±100,3 µmol/g vs 28,4±37,9 in MCHT group, p<0,0001). In the TBI group the patients who had DFO treatment had higher PIC (223,2±48,8 µmol/g vs 55,7±10,5 without DFO treatment, p<0,0001), and all patients having PIC >100 µmol/g at follow up had DFO-based chelation therapy, versus 26% of those with lower PIC (p<0,0001). The number of patients presenting exocrine pancreatic dysfunctions one month after transplantation was significantly higher in the TBI group (48% vs 4%; p<0.0001). The mean pancreatic volume reduction was significantly greater in the TBI group (39,1% vs 0,9% in the MCHT group; p<0,05), and was significantly worse on those who received DFO therapy. Based on our data, we suggest that TBI is detrimental for pancreatic functions, and speculate that DFO may contribute to the rapid pancreatic IO observed in these patients.

Safety and tolerability of deferasirox in pediatric hematopoietic stem cell transplant recipients: one facility's five years' experience of chelation treatment.

42 pediatric patients with iron overload, who underwent liver biopsy and DFX treatment after hematopoietic stem cell transplantation were included in the study group. The patients were divided into two groups diversified according to deferasirox trough plasma concentrations (DFX Ctrough) with cut-off equal to10 mcg/mL. The average dose of DFX was 25.9 mg/kg in the DFX Ctrough < 10 mcg/mL group versus 19.2 mg/kg in the DFX Ctrough > 10 mcg/mL group (p=0,0003). The mean duration of DFX treatment was 135.7 days in the DFX Ctrough < 10 mcg/mL group versus 41.8 days in the DFX Ctrough > 10 mcg/mL group (p<0.0001). The mean tissue iron concentration in the DFX Ctrough < 10 mcg/mL group was 261.9 µmol/g versus 133.4 µmol/g in the DFX Ctrough > 10 mcg/mL group (p < 0.0001). 21 patients (100%) in the DFX Ctrough > 10 mcg/mL group had ductopenia which was complete in 47.6% of them and severe in 52.4%. All patients with particularly high Ctrough (> 25 mcg/mL) were found to have total ductopenia. 90.5% of all deferasirox-related adverse events and 100% of major adverse events occurred in the DFX Ctrough > 10 mcg/mL group. In the DFX Ctrough < 10 mcg/mL group only one patient interrupted chelation therapy versus 16 (84.2%) patients in the DFX Ctrough > 10 mcg/mL group. We would recommend a close monitoring in pediatric hematopoietic transplant recipients subjected to deferasirox-based therapy because we have observed a high incidence of adverse events and discontinuation of chelation treatment.

MRI-based evaluation of multiorgan iron overload is a predictor of adverse outcomes in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation.

The medical records of 44 pediatric patients who underwent allogeneic transplantation from 2011 to 2015 were retrospectively reviewed. Magnetic resonance imaging was used to measure iron concentrations in the liver, spleen, pancreas and bone. These patients were divided into two groups, 18 with non-elevated (< 100 µmol/g; Group 1) liver iron concentration before transplantation and 26 with elevated (> 100 µmol/g; Group 2) concentration . We compared transplant-related outcomes in the two groups. Iron overload was a negative prognostic risk factor for sinusoidal obstruction syndrome (OR = 17), osteoporosis (OR = 6.8), pancreatic insufficiency (OR = 17) and metabolic syndrome (OR = 15.1). No statistically significant differences in overall survival, disease-free survival, relapse incidence and incidence of acute or chronic graft-versus host disease were observed between the two groups. Mean times to engraftment of platelets (43.0 ± 35.3 days vs. 22.1 ± 9.5 days, p < 0.05) and neutrophils (23.1 ± 10.4 days vs. 17.8 ± 4.6 days, p < 0.05) appear significantly longer in Group 2 than in Group 1. Time to platelet engraftment showed statistically significant correlation with pre-transplant liver (r = 0.5775; p < 0.001) and bone iron concentration (r = 0.7305; p < 0.001). Post-transplant evaluation pointed out that iron concentration analyzed at the first follow-up peaked in all tissues. The iron accumulation was highest in bone, followed by the spleen, liver and pancreas. One year post transplant 9 of 18 (50%) patients in Group 1 and 6 of 22 (27%) in Group 2 presented with bone and/or spleen iron overload, but not with liver overload. Liver iron concentration is not always a reliable indicator of systemic siderosis or of the efficacy of chelation therapy.