Efficacy of off-the-shelf bone marrow mesenchymal stem cells for pediatric steroid-refractory acute graft-versus-host disease.

Introduction: Temcell is a mesenchymal stem cell (MSC) product approved for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in Japan. However, reports regarding Temcell's efficacy in pediatric patients have been scarce, and the appropriate use of MSC therapy against pediatric SR-aGVHD also remains to be determined. Patients and Methods: We retrospectively assessed a cohort of pediatric patients treated with Temcell for SR-aGVHD following allogeneic hematopoietic transplantation. MSCs were infused intravenously at a dose of 2 × 106 cells/kg according to the manufacturer's instructions. Results: Twelve patients received eighteen cycles of MSC therapy (median age, 10.3 [1.7-17.8] years), with four receiving additional cycles (one cycle: n = 3, three cycles: n = 1). The severity of aGVHD before MSC therapy was grade I-II in three patients and grade III-IV in nine patients (gut stage 3-4, n= 7; liver stage 3-4; n =2). The median number of immunosuppressive therapy regimens received prior to MSC administration was two (range: 1-5). The first MSC cycle displayed the best overall response rate of 83%, including six patients with a complete response (CR) and with a 49% reduction in the mean daily dose of prednisone after eight weeks. The median time to first response was 3.5 days (range: 2-15 days). Two of the four patients who were re-administered MSCs for recurrent or persistent GVHD achieved a CR. The three-year overall survival rate was 69.4%, while the three-year failure free survival (FFS) rate was 22.2%, with a median FFS of 4.9 months. There were no observable side effects of MSC therapy. Conclusions: MSC therapy appears to be an effective and safe treatment for pediatric SR-aGVHD, with a steroid-sparing effect and satisfactory efficacy upon re-administration. Further studies are needed to determine its appropriate combination with additional treatments and the optimal use of re-administration of MSCs.

Nelarabine-containing salvage therapy and conditioning regimen in transplants for pediatric T-cell acute lymphoblastic leukemia and lymphoma.

Therapy for relapsed or refractory (r/r) T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in children is challenging, and new treatment methods are needed. We retrospectively analyzed eight patients with r/r T-ALL (five patients) and T-LBL (three patients) who were treated with nelarabine (NEL) plus etoposide, cyclophosphamide, and intrathecal therapy, administered 3 days apart. Five patients achieved a complete response, and the other three achieved a partial response (PR). All patients underwent hematopoietic stem cell transplantation (HSCT) after two cycles of treatment, except for one patient who received one cycle. Three patients who had previously received HSCT were treated with reduced-intensity conditioning regimens, including fludarabine, melphalan, and NEL; one survived for over 5 years after the second HSCT. Grade 2 neuropathy occurred in one patient, but other severe toxicities commonly associated with NEL were not observed during NEL administration in combination with chemotherapy. The 2-year overall survival and event-free survival rates were 60.0% and 36.5%, respectively. The addition of NEL to reinduction chemotherapy was useful in achieving remission and did not lead to excessive toxicity. In addition, a conditioning regimen, including NEL, appeared to be effective in patients who had previously undergone HSCT.

Long-term efficacy and safety profile of splenectomy for pediatric chronic immune thrombocytopenia.

There are few reports of the long-term efficacy of splenectomy in children with immune thrombocytopenia (ITP). In a 33-year period, we performed splenectomies in 23 pediatric patients with ITP at a single institution in Japan. The age at surgery was 5-22 years with a median of 10 years. The follow-up period was 1-141 months with a median of 48 months. Before surgery, we confirmed the presence or absence of the accessory spleen by contrast-enhanced CT scan and we recommended vaccination with pneumococcal vaccine. Four patients underwent laparotomy before 1998, and 19 patients underwent laparoscopic surgery after 1999. Splenectomy showed high efficacy with a partial response rate of 83% and a complete response rate of 74%. Complete response was maintained in 70% of patients until the end of the observation period, and 91% were able to discontinue long-term management drugs such as steroids. No serious complications such as infectious diseases were observed. Although the number of cases here was small, the long-term efficacy and safety of splenectomy makes it a viable option in pediatric ITP despite the existence of newer therapeutic agents. Further research is necessary to compare the long-term efficacy and safety of splenectomy with new therapeutic agents.

Predictive risk score of respiratory complications in children with mediastinal tumors: A case-control study.

BACKGROUND: The aim of this study was to examine risk factors of respiratory complications at the diagnosis and establish an algorithm of clinical management in children and adolescents with mediastinal tumors. METHODS: We retrospectively collected clinical information of all children and adolescents who presented with mediastinal tumors at Saitama Children's Medical Center from 1999 to 2019, including age, sex, pathological diagnosis, eight major clinical symptoms (cough, dyspnea, hypoxia, orthopnea, chest pain, wheeze, superior vena cava syndrome, and stridor), chest computed tomography (CT) findings (tumor location, mediastinal mass ratio, pleural fluid, pericardial effusion, and compression of trachea and bronchi), types of diagnostic procedure and anesthesia, respiratory complications (severe hypoxia, difficult ventilation, respiratory failure, and cardiopulmonary arrest), and clinical outcome. Subsequently, we calculated the risk score for predicting respiratory complications by combining clinical and radiological findings. RESULTS: Of the 57 patients, 7 (12%) developed respiratory complications. Cough, dyspnea, hypoxia, and orthopnea were significantly more common in patients with complications (p = 0.02, p = 0.02, p < 0.01, p = 0.03, respectively). The reduction of percentage of tracheal cross-sectional area (%TCA) and compression of the carina in chest CT were also significantly more common in patients with complications (p < 0.01 and <0.01, respectively). We calculated the risk score of respiratory complications by combining cough, wheeze, stridor, orthopnea, dyspnea, hypoxia, %TCA < 0.5, and compression of the carina. A risk score ≥ 7 showed high predictive accuracy for complications (sensitivity: 100%, specificity: 97.7%, positive likelihood ratio: 43.0). CONCLUSION: The risk score combining clinical symptoms with radiological findings is a promising predictive tool for respiratory complications in children with mediastinal tumors.

Initial ultrasound evaluation of an anterior mediastinal mass ultimately diagnosed as T-cell acute lymphoblastic leukemia: a report of three cases in children.

Pediatric T-cell acute lymphoblastic leukemia (T-ALL) in the anterior mediastinum has an acute onset and requires early treatment. The diagnostic strategy for anterior mediastinal masses in pediatric patients usually involves imaging evaluation, surgical biopsy, or resection for diagnosis and treatment. Thereafter, appropriate chemotherapy regimen selection is based on the pathological diagnosis. In some cases, general anesthesia is avoided to prevent complications such as airway compression and circulatory collapse. We present 3 cases with T-ALL where ultrasound was used for the first evaluation of the anterior mediastinal mass. A 5-year-old girl had lymph node swelling at the supraclavicular fossa. Ultrasound examination showed a huge anterior mediastinal mass with an abnormal thymus, surrounding the proximal main trachea in the mediastinum. These sonographic findings indicated a possibility for tracheal compression during general anesthesia. A 12-year-old boy had dyspnea. Ultrasound examination showed a massive pericardial effusion and stenosis of the right pulmonary artery. These sonographic findings indicated a risk of circulation collapse. An 8-year-old boy had cervical swelling and dyspnea. Ultrasound examination showed a huge mass on the anterior mediastinum and a huge thrombus in the left atrium. This sonographic finding indicated a risk of thromboembolism. Ultrasonography is useful in pediatric patients with anterior mediastinal masses due to T-ALL. By focusing on the thymus, a diagnosis of T-ALL might be recommended. To avoid catastrophic circulation collapse, tracheal and vascular compression should be evaluated. Direct invasion may also be detectable.

A geometrical pitfall of Area-Length method; -Is left ventricle volume evaluation of repaired Tetralogy of Fallot by angiocardiography accurate?

Biplane Area-Length (AL) method by left ventriculography (LVG) has been widely adopted as a standard method to estimate left ventricular volume. However, we have experienced difficulties in adopting the value by AL method for the children with Tetralogy of Fallot (TOF) due to the discrepancy among volumetric modalities. This study validated some limitations of AL method, considering the basic principles of its formulation. A single center retrospective cohort study was conducted for 1 year. The confirmed 22 cases with repaired TOF at our hospital were enrolled. The clinical characteristics, some cardiac MRI analyses, and all the cardiac catheterization studies were collected. Angiographic data were compared with historic cohorts of Kawasaki disease without any coronary artery lesions by using AL method. Cardiac MRI analyses of ten TOF patients were additionally available. LVG studies showed that the length of the long axis on anteroposterior view (AP) was not equal to that on lateral view (LT) due to anatomically apical elevation in TOF, followed by a significant difference found in the sagittal lengths of the LV long axis between AP and LT (P = 0.003). Because the difference critically affected the formula depending on biplane AL method, the calculated LVEDV of TOF group appeared overestimated, compared with the control group (TOF vs control group: 119.5% ± 6.3% vs 96.4 ± 3.5% of Normal, P = 0.006). Available cardiac MRI analyses of some patients in TOF group revealed 55% increase of LVEDV by AL method (angiocardiography 116 ± 7.0 vs CMR 75 ± 3.7 ml/m2, P = 0.0025). A pitfall exists when applying biplane AL method to measure LV volume especially for TOF patients, because the long axis on AP view is not always identical to that on LT view.

Successful perioperative management using prothrombin complex concentrates in patients with severe congenital protein C deficiency.

Perioperative management of severe congenital protein C deficiency remains unestablished. This deficiency is often treated with anticoagulants, such as warfarin. Although anticoagulants need to be perioperatively discontinued, there are few methods for the management of such patients. We adopted a method for administering prothrombin complex concentrates (PCC), which includes intermittent administration of inactive protein C (PPSB-HT), and examined its outcome as a perioperative management approach for severe congenital protein C deficiency. Three patients underwent our perioperative management six times. We monitored activity levels of protein C, factor IX, and so forth. These patients could be perioperatively managed with PCC treatment.

[Thrombopoietin receptor agonists for pediatric refractory chronic immune thrombocytopenia].

Various treatments have been used to treat chronic immune thrombocytopenic purpura in children; however, none of it has been established as the standard of care. The administration of thrombopoietin receptor agonists (TPO-RAs) has been approved as a new treatment option in Japan. In this case series, TPO-RAs were administered to 16 patients (eltrombopag, n=9; romiplostim, n=7). Excluding the data of two patients who underwent splenectomy immediately after starting treatment with these medicines, platelet counts increased to ≥50,000/µl in seven patients. The adverse events recorded were grade 2 liver dysfunction (n=1), according to the common terminology criteria for adverse events version 4, and myelofibrosis (classified as MF1 or mild reticulin fibrosis), as observed on bone marrow biopsy (n=2). We continued the administration of TPO-RAs at the same dose in these patients because the complications they experienced were mild. The risk of adverse events associated with long-term use of TPO-RAs in this pediatric population remains unclear, and a prospective evaluation is needed.

Non-microtubule tubulin-based backbone and subordinate components of postsynaptic density lattices.

A purification protocol was developed to identify and analyze the component proteins of a postsynaptic density (PSD) lattice, a core structure of the PSD of excitatory synapses in the central nervous system. "Enriched"- and "lean"-type PSD lattices were purified by synaptic plasma membrane treatment to identify the protein components by comprehensive shotgun mass spectrometry and group them into minimum essential cytoskeleton (MEC) and non-MEC components. Tubulin was found to be a major component of the MEC, with non-microtubule tubulin widely distributed on the purified PSD lattice. The presence of tubulin in and around PSDs was verified by post-embedding immunogold labeling EM of cerebral cortex. Non-MEC proteins included various typical scaffold/adaptor PSD proteins and other class PSD proteins. Thus, this study provides a new PSD lattice model consisting of non-microtubule tubulin-based backbone and various non-MEC proteins. Our findings suggest that tubulin is a key component constructing the backbone and that the associated components are essential for the versatile functions of the PSD.

The E3 ubiquitin ligase MIB2 enhances inflammation by degrading the deubiquitinating enzyme CYLD.

The tumor suppressor CYLD is a deubiquitinating enzyme that suppresses polyubiquitin-dependent signaling pathways, including the proinflammatory and cell growth-promoting NF-κB pathway. Missense mutations in the CYLD gene are present in individuals with syndromes such as multiple familial trichoepithelioma (MFT), but the pathogenic roles of these mutations remain unclear. Recent studies have shown that CYLD interacts with a RING finger domain protein, mind bomb homologue 2 (MIB2), in the regulation of NOTCH signaling. However, whether MIB2 is an E3 ubiquitin ligase that acts on CYLD is unknown. Here, using the cell-free-based AlphaScreen and pulldown assays to detect protein-protein interactions, along with immunofluorescence assays and murine Mib2 knockout cells and animals, we demonstrate that MIB2 promotes proteasomal degradation of CYLD and enhances NF-κB signaling. Of note, arthritic inflammation was suppressed in Mib2-deficient mice. We further observed that the ankyrin repeat in MIB2 interacts with the third CAP domain in CYLD and that MIB2 catalyzes Lys-48-linked polyubiquitination of CYLD at Lys-338 and Lys-530. MIB2-dependent CYLD degradation activated NF-κB signaling via tumor necrosis factor alpha (TNFα) stimulation and the linear ubiquitination assembly complex (LUBAC). Mib2-knockout mice had reduced serum interleukin-6 (IL-6) and exhibited suppressed inflammatory responses in the K/BxN serum-transfer arthritis model. Interestingly, MIB2 significantly enhanced the degradation of a CYLDP904L variant identified in an individual with MFT, although the molecular pathogenesis of the disease was not clarified here. Together, these results suggest that MIB2 enhances NF-κB signaling in inflammation by promoting the ubiquitin-dependent degradation of CYLD.

[Allogeneic hematopoietic stem cell transplantation using myeloablative conditioning including total body irradiation for pediatric acute lymphoblastic leukemia: a single-center retrospective analysis].

This study aimed to investigate the clinical outcomes of hematopoietic stem cell transplantation (HSCT) with total body irradiation-based myeloablative conditioning (TBI-MAC) in pediatric patients with acute lymphoblastic leukemia (ALL). We retrospectively examined patients with ALL who underwent HSCT with TBI-MAC from January 2000 to August 2016 at our institute. We enrolled 67 patients with a median follow-up period of 8 years. The 5-year event-free survival (EFS) and overall survival (OS) were 51.2% and 59.6%, respectively. At the first complete remission, HSCT exhibited significantly superior EFS and OS in our patients than that in patients with other diseases. We encountered 57.9% of patients with at least one late complication. Major late complications were short stature (26.3%) and hypogonadism (18.4%). While late complications were observed in several recipients of HSCT, late complication-related deaths occurred in three patients. The TBI-MAC regimen led to favorable clinical outcomes in pediatric patients with ALL who underwent HSCT. Thus, proper evaluation and management of late complications are mandatory.