Risk factors for severe acute kidney injury after pediatric hematopoietic cell transplantation.

BACKGROUND: Acute kidney injury (AKI) is common after hematopoietic cell transplantation (HCT) and is associated with poorer outcomes. Risk factors for AKI after pediatric HCT are not fully understood. The study objective was to assess unique risk factors for AKI in the HCT population and evaluate post-HCT AKI patterns. METHODS: We conducted a retrospective cohort study of patients < 21 years of age who underwent HCT at Seattle Children's Hospital/Fred Hutchinson Cancer Center from September 2008 to July 2017 (n = 484). We defined AKI using KDIGO criteria. We collected demographics, baseline HCT characteristics, post-HCT complications, and mortality. Multinomial logistic regression was used to estimate association between AKI and potential risk factors. We used adjusted Cox proportional hazard ratios to evaluate differences in mortality. RESULTS: One hundred and eighty-six patients (38%) developed AKI. Seventy-nine (42%) had severe AKI and 27 (15%) required kidney replacement therapy. Fluid overload was common in all groups and 67% of those with severe AKI had > 10% fluid overload. Nephrology was consulted in less than 50% of those with severe AKI. In multivariable analysis, risk of severe AKI was lower in those taking a calcineurin inhibitor (CNI). Risk of death was higher in severe AKI compared to no AKI (RR 4.6, 95% CI 2.6-8.1). CONCLUSIONS: AKI and fluid overload are common in pediatric patients after HCT. Severe AKI occurred less often with CNI use and was associated with higher mortality. Future interventions to reduce AKI and its associated complications such as fluid overload are approaches to reducing morbidity and mortality after HCT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Effective Multi-lineage Engraftment in a Mouse Model of Fanconi Anemia Using Non-genotoxic Antibody-Based Conditioning.

Conditioning chemotherapy is used to deplete hematopoietic stem cells in the recipient's marrow, facilitating donor cell engraftment. Although effective, a major issue with chemotherapy is the systemic genotoxicity that increases the risk for secondary malignancies. Antibody conjugates targeting hematopoietic cells are an emerging non-genotoxic method of opening the marrow niche and promoting engraftment of transplanted cells while maintaining intact marrow cellularity. Specifically, this platform would be useful in diseases associated with DNA damage or cancer predisposition, such as dyskeratosis congenita, Schwachman-Diamond syndrome, and Fanconi anemia (FA). Our approach utilizes antibody-drug conjugates (ADC) as an alternative conditioning regimen in an FA mouse model of autologous transplantation. Antibodies targeting either CD45 or CD117 were conjugated to saporin (SAP), a ribosomal toxin. FANCA knockout mice were conditioned with either CD45-SAP or CD117-SAP prior to receiving whole marrow from a heterozygous healthy donor. Bone marrow and peripheral blood analysis revealed equivalent levels of donor engraftment, with minimal toxicity in ADC-treated groups as compared with cyclophosphamide-treated controls. Our findings suggest ADCs may be an effective conditioning strategy in stem cell transplantation not only for diseases where traditional chemotherapy is not tolerated, but also more broadly for the field of blood and marrow transplantation.

HLA-Haploidentical Hematopoietic Cell Transplantation for Treatment of Nonmalignant Diseases Using Nonmyeloablative Conditioning and Post-Transplant Cyclophosphamide.

Allogeneic hematopoietic cell transplant (HCT) is often the only curative therapy for patients with nonmalignant diseases; however, many patients do not have an HLA-matched donor. Historically, poor survival has been seen after HLA-haploidentical HCT because of poor immune reconstitution, increased infections, graft-versus-host disease (GVHD), and graft failure. Encouraging results have been reported using a nonmyeloablative T cell-replete HLA-haploidentical transplant approach in patients with hematologic malignancies. Here we report the outcomes of 23 patients with various nonmalignant diseases using a similar approach. Patients received HLA-haploidentical bone marrow (n = 17) or granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (n = 6) grafts after conditioning with cyclophosphamide 50 mg/kg, fludarabine 150 mg/m2, and 2 or 4 Gy total body irradiation. Postgrafting immunosuppression consisted of cyclophosphamide, mycophenolate mofetil, tacrolimus, ± sirolimus. Median patient age at HCT was 10.8 years. Day 100 transplant-related mortality (TRM) was 0%. Two patients died at later time points, 1 from intracranial hemorrhage/disseminated fungal infection in the setting of graft failure and 1 from infection/GVHD. The estimated probabilities of grades II to IV and III to IV acute GVHD at day 100 and 2-year National Institutes of Health consensus chronic GVHD were 78%, 26%, and 42%, respectively. With a median follow-up of 2.5 years, the 2-year overall and event-free rates of survival were 91% and 78%, respectively. These results are encouraging and demonstrate favorable disease-specific lineage engraftment with low TRM in patients with nonmalignant diseases using nonmyeloablative conditioning followed by T cell-replete HLA-haploidentical grafts. However, additional strategies are needed for GVHD prevention to make this a viable treatment approach for patients with nonmalignant diseases.

Potential for cellular stress response to hepatic factor VIII expression from AAV vector.

Hemophilia A and B are coagulation disorders resulting from the loss of functional coagulation factor VIII (FVIII) or factor IX proteins, respectively. Gene therapy for hemophilia with adeno-associated virus vectors has shown efficacy in hemophilia B patients. Although hemophilia A patients are more prevalent, the development of therapeutic adeno-associated virus vectors has been impeded by the size of the F8 cDNA and impaired secretion of FVIII protein. Further, it has been reported that over-expression of the FVIII protein induces endoplasmic reticulum stress and activates the unfolded protein response pathway both in vitro and in hepatocytes in vivo, presumably due to retention of misfolded FVIII protein within the endoplasmic reticulum. Engineering of the F8 transgene, including removal of the B domain (BDD-FVIII) and codon optimization, now allows for the generation of adeno-associated virus vectors capable of expressing therapeutic levels of FVIII. Here we sought to determine if the risks of inducing the unfolded protein response in murine hepatocytes extend to adeno-associated virus gene transfer. Although our data show a mild activation of unfolded protein response markers following F8 gene delivery at a certain vector dose in C57BL/6 mice, it was not augmented upon further elevated dosing, did not induce liver pathology or apoptosis, and did not impact FVIII immunogenicity.

Left Ventricular Metastasis in Neuroblastoma: A Case Report.

Neuroblastoma is the most common extracranial solid tumor in children. Most common sites of metastases from neuroblastoma are bone marrow, bone and lymph nodes, however cardiac metastasis is rarely seen. Metastatic cardiac tumors are 20 to 40 times more common than primary cardiac tumors. Mechanism of cardiac metastasis can be hematogenous, lymphatogenous, and direct extension/infiltration of tumor cells. Usually right heart metastasis is seen. Left ventricular metastatic tumor has never been reported with neuroblastoma.

Store-operated cyclic AMP signalling mediated by STIM1.

Depletion of Ca(2+) from the endoplasmic reticulum (ER) results in activation of plasma membrane Ca(2+) entry channels. This 'store-operated' process requires translocation of a transmembrane ER Ca(2+) sensor protein, stromal interaction molecule 1 (STIM1), to sites closely apposed to Ca(2+) channels at the cell surface. However, it is not known whether a reduction in Ca(2+) stores is coupled to other signalling pathways by this mechanism. We found that lowering the concentration of free Ca(2+) in the ER, independently of the cytosolic Ca(2+) concentration, also led to recruitment of adenylyl cyclases. This resulted in enhanced cAMP accumulation and PKA activation, measured using FRET-based cAMP indicators. Translocation of STIM1 was required for efficient coupling of ER Ca(2+) depletion to adenylyl cyclase activity. We propose the existence of a pathway (store-operated cAMP signalling or SOcAMPS) in which the content of internal Ca(2+) stores is directly connected to cAMP signalling through a process that involves STIM1.