A Japanese retrospective study of non-tuberculous mycobacterial infection in children, adolescents, and young adult patients with hematologic-oncologic diseases.

Non-tuberculous mycobacterial infection (NTM) is rare in healthy children, with lymphadenitis being the most common presentation. Immunocompromised populations are known to be at high risk, but the clinical picture of NTM infection in pediatric hematology/oncology patients is unclear. In this nationwide retrospective analysis of patients under the age of 40 treated in Japanese pediatric hematology/oncology departments who developed NTM infection between January 2010 and December 2020, 36 patients (21 patients with hematopoietic stem cell transplantation (HSCT) and 15 nontransplant patients) were identified. Post-transplant patients were infected with NTM at 24 sites, including the lungs (n = 12), skin and soft tissues (n = 6), bloodstream (n = 4), and others (n = 2). Nine of twelve patients with pulmonary NTM infection had a history of pulmonary graft-versus-host disease (GVHD), and rapid-growing mycobacteria (RGM) were isolated from five of them. In nontransplant patients, the primary diseases were acute lymphoblastic leukemia (ALL; n = 5), inborn errors of immunity (IEI; n = 6), and others (n = 4). All cases of ALL had bloodstream infections with RGM, whereas all cases of IEI were infected with slow-growing mycobacteria (SGM). In summary, three typical clinical scenarios for pediatric hematology/oncology patients have been established: RGM-induced pulmonary disease in patients with pulmonary GVHD, RGM bloodstream infection in patients with ALL, and SGM infection in patients with IEI. Our findings suggest that NTM must be regarded as a pathogen for infections in these high-risk patients, especially those with pulmonary GVHD, who may require active screening for NTM.

Vedolizumab for children with intestinal graft-versus-host disease: a case report and literature review.

Acute graft-versus-host disease (aGVHD) is a challenging complication of allogeneic hematopoietic stem cell transplantation, and alternative therapies for patients showing inadequate response to steroids are limited. Vedolizumab, an anti-α4ß7 integrin antibody widely used for treating inflammatory bowel diseases, has recently been studied in adult patients with steroid-refractory intestinal aGVHD. However, few studies have examined its safety and effectiveness in pediatric patients with intestinal aGVHD. We report the case of a male patient with intestinal late-onset aGVHD treated with vedolizumab. He underwent allogeneic cord blood transplantation for warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome and developed intestinal late-onset aGVHD 31 months after transplantation. The patient was refractory to steroids; however, vedolizumab was initiated 43 months after transplantation (at the age of 7 years) and the symptoms of intestinal aGVHD were alleviated. Additionally, favorable endoscopic findings were observed, such as reduction of erosion and regenerative epithelial growth. We also evaluated the efficacy of vedolizumab in 10 patients with intestinal aGVHD (9 from the literature review and the present case). Six patients (60%) showed an objective response to vedolizumab. No serious adverse events were observed in any patients. Vedolizumab is a potential treatment option for steroid-refractory intestinal aGVHD in pediatric patients.

Human leukocyte antigen 7/8-matched unrelated bone marrow transplantation using anti-thymocyte globulin in children.

Human leukocyte antigen (HLA) mismatched unrelated donor transplantation is associated with an increased risk of graft-versus-host disease, graft failure, and infection, which increases post-transplant morbidity and mortality. In this single-center retrospective study, outcomes were evaluated in 30 consecutive children who underwent bone marrow transplantation (BMT) from HLA 1 allele-mismatched (HLA 7/8-matched) unrelated donors with rabbit anti-thymocyte globulin (rATG) as graft-versus-host disease (GVHD) prophylaxis. The 3-year overall survival (OS), event-free survival (EFS), and GVHD-relapse-free survival rates were 91.7% (95% CI 70.5%-91.9%), 88.3% (95% CI 67.5%-96.1%), and 73.9% (95% CI 52.4%-86.8%), respectively. Grade II-IV and III-IV acute GVHD occurred in 10 (33%) and 2 (7.0%) patients, respectively. The 3-year cumulative incidence of chronic GVHD was 7.8%. No fatal viral infections occurred. The study results show the feasibility of HLA 7/8-matched unrelated BMT with ATG to achieve favorable outcomes and acceptable GVHD, especially for patients who lack a fully matched donor.

Clinical Impact of Melphalan Pharmacokinetics on Transplantation Outcomes in Children Undergoing Hematopoietic Stem Cell Transplantation.

Melphalan is widely used for hematopoietic stem cell transplantation (HSCT) conditioning. However, the relationship between its pharmacokinetic (PK) and transplantation outcomes in children has not been thoroughly investigated. We prospectively analyzed the relationship between melphalan area under the curve (AUC) and transplantation outcome and examined the development of a predictive model for melphalan clearance in children. This study included 43 children aged 0 to 19 years who underwent HSCT following a melphalan-based conditioning regimen from 2017 to 2021. In univariable analysis, high-melphalan AUC resulted in a significantly lower cumulative incidence of acute graft-versus-host disease and a higher cumulative incidence of thrombotic microangiopathy, although no significant difference was observed in survival. Regression analysis of a randomly selected derivation cohort (n = 21) revealed the following covariate PK model: predicted melphalan clearance (mL/min) = 6.47 × 24-h urinary creatinine excretion rate (CER, g/day) × 24-h creatinine clearance rate (CCR, mL/min) + 92.8. In the validation cohort (n = 22), the measured melphalan clearance values were significantly correlated with those calculated based on the prediction equation (R2 = 0.663). These results indicate that melphalan exposure may be optimized by adjusting the melphalan dose according to CER and CCR.

Risk factors for unplanned removal of central venous catheters in hospitalized children with hematological and oncological disorders.

Central venous catheters (CVCs) are essential devices in the treatment of pediatric patients with hematological and oncological disorders; however, the most suitable type of CVC for these patients remains unclear. We retrospectively compared risk factors for unplanned removal of two commonly used CVCs, peripherally inserted central catheters (PICCs) and tunneled CVCs, to propose which is the better device. We followed 89 patients fitted with a tunneled CVC (total 21,395 catheter-days) and 84 fitted with a PICC (total 9177 catheter-days) between January 1, 2013 and December 31, 2015, until catheter removal. Patients with a PICC had a significantly higher 3-month cumulative incidence of catheter occlusion (5.2% vs. 0%, p = 4.08 × 10-3) and total unplanned removals (29.0% vs. 6.9%, p = 0.0316) than those with tunneled CVCs. However, the cumulative incidence of central line-associated bloodstream infection did not differ significantly by CVC type. Multivariable analysis identified younger age (< 2 years) [sub-distribution hazard ratio (SHR) 2.29; 95% confidence interval (CI) 1.27-4.14] and PICC (SHR 2.73; 95% CI 1.48-5.02) as independent risk factors for unplanned removal. Thus, our results suggest that tunneled CVCs are preferable in pediatric patients with hematological and oncological disorders requiring long-term, intensive treatment.

Combination chemotherapy consisting of irinotecan, etoposide, and carboplatin for refractory or relapsed neuroblastoma.

BACKGROUND: Patients with primary refractory and relapsed neuroblastoma have a poor prognosis since safe and effective chemotherapies for these patients are currently limited. The development of new chemotherapy regimens for these patients is imperative to improve survival outcomes. METHODS: We retrospectively analyzed 40 patients with refractory (n = 36) or relapsed (n = 4) neuroblastoma who received irinotecan, etoposide, and carboplatin (IREC) as a second-line treatment. We evaluated their therapeutic response and the toxicity of IREC. We also assessed the impact of UGT1A1 gene polymorphisms, which are involved in irinotecan metabolism, on outcomes and toxicity. RESULTS: A total of 112 cycles of IREC were administered to 40 patients with a median of 2 cycles per patient (range, 1-9). Six (15%) patients (UGT1A1 wild-type [n = 2] and heterozygous [n = 4]) showed objective responses, including partial response (n = 1), tumor shrinkage (n = 4), and improved findings on their MIBG scan (n = 1). Grade 4 neutropenia, grade 4 leukopenia, and grades 3-4 gastrointestinal toxicity were observed in 110 (98%), 88 (79%), and 3 (3%) cycles, respectively. There was no IREC-related mortality. Patients with UGT1A1 polymorphisms showed a higher frequency of grade 4 leukopenia, but these patients did not have increased treatment-related mortality or non-hematologic toxicity. CONCLUSIONS: IREC showed an objective response rate of 15% including 1 case with partial response. IREC was well tolerated regardless of UGT1A1 genotype. This study suggests that IREC is a promising second-line chemotherapy for refractory or relapsed neuroblastoma.

Simple and robust methylation test for risk stratification of patients with juvenile myelomonocytic leukemia.

Juvenile myelomonocytic leukemia (JMML) is a rare myelodysplastic/myeloproliferative neoplasm that develops during infancy and early childhood. The array-based international consensus definition of DNA methylation has recently classified patients with JMML into the following 3 groups: high (HM), intermediate (IM), and low methylation (LM). To develop a simple and robust methylation clinical test, 137 patients with JMML were analyzed using the Digital Restriction Enzyme Analysis of Methylation (DREAM), which is a next-generation sequencing-based methylation analysis. Unsupervised consensus clustering of the discovery cohort (n = 99) using DREAM data identified HM (HM_DREAM; n = 35) and LM subgroups (LM_DREAM; n = 64). Of the 98 cases that could be compared with the international consensus classification, 90 HM (n = 30) and LM (n = 60) cases had 100% concordance with DREAM clustering results. Of the remaining 8 cases comprising the IM group, 4 were classified as belonging to the HM_DREAM group and 4 to the LM_DREAM group. A machine-learning classifier was successfully constructed using a support vector machine (SVM), which divided the validation cohort (n = 38) into HM (HM_SVM, n = 18) and LM (LM_SVM; n = 20) groups. Patients with the HM_SVM profile had a significantly poorer 5-year overall survival rate than those with the LM_SVM profile. In conclusion, we developed a robust methylation test using DREAM for patients with JMML. This simple and straightforward test can be easily incorporated into diagnosis to generate a methylation classification for patients so they can receive risk-adapted treatment in the context of future clinical trials.

Integrated diagnosis based on transcriptome analysis in suspected pediatric sarcomas.

Pediatric solid tumors are a heterogeneous group of neoplasms with over 100 subtypes. Clinical and histopathological diagnosis remains challenging due to the overlapping morphological and immunohistochemical findings and the presence of atypical cases. To evaluate the potential utility of including RNA-sequencing (RNA-seq) in the diagnostic process, we performed RNA-seq in 47 patients with suspected pediatric sarcomas. Histopathologists specialized in pediatric cancer re-evaluated pathological specimens to reach a consensus diagnosis; 42 patients were diagnosed with known subtypes of solid tumors whereas 5 patients were diagnosed with undifferentiated sarcoma. RNA-seq analysis confirmed and refined consensus diagnoses and further identified diagnostic genetic variants in four of the five patients with undifferentiated sarcoma. Genetic lesions were detected in 23 patients, including the novel SMARCA4-THOP1 fusion gene and 22 conventional or recently reported genetic events. Unsupervised clustering analysis of the RNA-seq data identified a distinct cluster defined by the overexpression of rhabdomyosarcoma-associated genes including MYOG and CHRNG. These findings suggest that RNA-seq-based genetic analysis may aid in the diagnosis of suspected pediatric sarcomas, which would be useful for the development of stratified treatment strategies.

Echocardiography Monitoring of Pulmonary Hypertension after Pediatric Hematopoietic Stem Cell Transplantation: Pediatric Pulmonary Arterial Hypertension and Pulmonary Veno-Occlusive Disease after Hematopoietic Stem Cell Transplantation.

Pulmonary hypertension (PH) is associated with high morbidity in children undergoing hematopoietic stem cell transplantation (HSCT). However, owing to the lack of sequential echocardiography, the nature of the condition is not fully understood. This study was conducted to investigate whether routine echocardiography performed after HSCT could detect patients with PH at an earlier stage and elucidate the role of intervention using tadalafil. The study population comprised 93 consecutive children age <18 years who underwent a total of 109 HSCTs. All patients underwent routine transthoracic echocardiography during HSCT. Four children (4%) with a median age of 4 years (range, 0.7 to 6 years) were found to have PH, and their median tricuspid regurgitation peak velocity (TRV) was 4.1 m/s (range, 3.5 to 4.2 m/s). PH was diagnosed at a median of 52 days (range, 21 to 118 days) after HSCT. Three of them were diagnosed with neuroblastoma, and 1 was diagnosed with infantile leukemia. One patient developed PH after autologous HSCT, and 3 received killer immunoglobulin-like receptor ligand-mismatched cord blood. Busulfan was used for conditioning in all patients, and the proportion of patients receiving this medication was significantly higher in the PH group compared with the non-PH group (100% versus 30%; P = .011). Three of the 4 patients had a durable response (TRV ≤2.8 m/s) at a median of 46 days (range, 14 to 79 days) after starting treatment with tadalafil. No patient experienced exacerbation of PH, and treatment was completed at median of 96 days (range, 46 to 212 days). Our data suggest that routine echocardiography monitoring after HSCT should be considered in children receiving busulfan, although the precise follow-up timing needs further study. In addition, safe and effective administration of tadalafil must be ensured by close monitoring.

Relationship between plasma rabbit anti-thymocyte globulin concentration and immunosuppressive therapy response in patients with severe aplastic anemia.

OBJECTIVES: Patients with acquired aplastic anemia (AA) without HLA-matched sibling donors or aged >40 years receive immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG). We investigated the relationship between plasma rabbit ATG (r-ATG) concentration and IST response. METHODS: From May 2012 to October 2017, 81 patients with severe AA who required initial IST were included. A 1:1 block randomization was employed for 2.5 and 3.5 mg/kg doses of r-ATG. RESULTS: No significant difference in response rates was observed between the 2.5 and 3.5 mg/kg groups (63% vs. 58%, P = .894). Median r-ATG concentrations on days 14 and 28 after IST were 15.2 (0.0-97.7) and 1.8 (0.0-74.9 µg/mL), respectively. According to r-ATG concentration, response rates were significantly higher in the group with higher r-ATG concentration than in those with lower r-ATG concentration (day 14, 88% vs. 52%; P = .006 and day 28, 79% vs. 46%; P = .005). In multivariate analysis, higher r-ATG concentrations at day 28 were independent predictors of favorable response to IST at 6 months (odds ratio, 0.29; 95% confidence interval, 0.09-0.93; P = .037). CONCLUSIONS: The present data indicate that higher r-ATG concentration at day 28 resulted in improved IST response.

Successful treatment of a novel type I interferonopathy due to a de novo PSMB9 gene mutation with a Janus kinase inhibitor.

BACKGROUND: Type I interferonopathies are a recently established subgroup of autoinflammatory diseases caused by mutations in genes associated with proteasome degradation or cytoplasmic RNA- and DNA-sensing pathways. OBJECTIVE: This study aimed to unveil the molecular pathogenesis of a patient with novel type I interferonopathy, for which no known genetic mutations have been identified. METHODS: We performed the whole-exome sequencing of a 1-month-old boy with novel type I interferonopathy. We also investigated proteasome activities using patient-derived B lymphoblastoid cell lines (LCLs) and normal LCLs transduced with the mutant gene. RESULTS: Whole-exome sequencing identified a de novo proteasome 20S subunit beta 9 (PSMB9) p.G156D mutation in the patient who developed fever, a chilblain-like skin rash, myositis, and severe pulmonary hypertension due to the hyperactivation of IFN-α. Patient-derived LCLs revealed reduced proteasome activities, and exogenous transduction of mutant PSMB9 p.G156D into normal LCLs significantly suppressed proteasome activities, and the endogenous PSMB9 protein was lost along with the reduction of other immunoproteasome subunits, PSMB8 and PSMB10 proteins. He responded to the administration of a Janus kinase inhibitor, tofacitinib, and he was successfully withdrawn from venoarterial extracorporeal membranous oxygenation. At age 7 months, he received an unrelated cord blood transplantation. At 2 years posttransplantation, he no longer required tofacitinib and experienced no disease recurrence. CONCLUSIONS: We present the case of a patient with a novel type I interferonopathy caused by a de novo PSMB9 p.G156D mutation that suppressed the wild-type PSMB9 protein expression. Janus kinase inhibitor and stem cell transplantation could be curative therapies in patients with severe interferonopathies.

Risk factors for secondary poor graft function after bone marrow transplantation in children with acquired aplastic anemia.

In patients with acquired AA, PGF is a major cause of cytopenia after hematopoietic stem cell transplantation. An increased incidence of PGF, especially sPGF, has been noted after the introduction of the FLU/CY regimen in children with acquired AA. To clarify the risk factors for sPGF, the clinical data of 49 patients (median age, 11 years; range, 1-19 years) with AA who received allogeneic BMT at Nagoya University Hospital from 1997 to 2016 were analyzed. Out of the 49 patients, 7 developed sPGF, and the 5-year CI was 0.15 (95% CI, 0.04-0.25). Five received the FLU/CY regimen, and the 5-year CI of sPGF was significantly higher in patients who received the regimen (0.36; 95% CI, 0.12-0.62) than in those who were conditioned with the non-FLU/CY regimen (0.06; 95% CI, 0.01-0.17; P = .01). The multivariate analysis confirmed that the FLU/CY regimen (hazard ratio, 6.12; 95% CI, 1.16-32.4; P = .03) was a significant risk factor for sPGF. sPGF improved spontaneously without stem cell boost infusions in 5 patients, ranging from 460 to 3539 days after BMT. The 10-year CI of the spontaneous trilineage recovery was 0.83 (95% CI, 0.00-0.97), and all 7 patients are alive. The FLU/CY regimen was identified as a risk factor for the sPGF development in patients with AA. The establishment of the optimal conditioning regimens for children with AA is warranted.

Is cell block technique useful to predict histological type in patients with ovarian mass and/or body cavity fluids?

The cell block (CB) technique is a generalized method utilized for the diagnostic evaluation of body cavity fluids. Ascites cytology is one of the most important diagnostic processes for epithelial ovarian cancer. However, in clinical practice, the usefulness of the CB method to diagnose this tumor remains unelucidated. Between 2008 and 2017, 15 peritoneal or pleural fluid samples obtained from patients with ovarian or peritoneal carcinoma or other gastrointestinal malignancies were preoperatively subjected to a diagnostic evaluation to predict the histological type and original organ. The CBs were made from 10% formalin neutral buffer solution fixed sediments of fluid samples after cytological smears were made by conventional method. Four-µm thickness sections were prepared from the cell blocks and stained with immunohistochemical method, using 16 kinds of antibodies and hematoxylin eosin staining method. The cellularity, architectural patterns, and morphological details were also studied. The median (range) age of patients was 73 (35-87) years. The clinical features were identified as follows: pleural effusion in 4, ovarian mass in 7, peritoneal dissemination in 12, para-aortic nodal swelling in one, and liver tumor in one (some overlapping). Five patients had a history of prior malignancy. Finally, we could accurately diagnose the histological type in 9 patients based on subsequent biopsy, surgery, and autopsy. In all 9 women, the clinical diagnosis, CB diagnosis and final pathological diagnosis were consistent. The CB technique may be a helpful modality for evaluating fluid cytology to obtain a final histopathologic diagnosis.

Whole abdominopelvic intensity-modulated radiation therapy for peritoneal disseminated rhabdomyosarcoma with three-year follow-up: a case report.

BACKGROUND: The role of local radiotherapy in the treatment of metastatic rhabdomyosarcoma is important. However, with peritoneal dissemination, the application of local therapy is challenging. Although there are few reports addressing the efficacy of the whole abdominopelvic irradiation to peritoneal disseminated rhabdomyosarcoma patients, no precise curse of treatment nor the follow up result is explained in paper nor in the text. CASE PRESENTATION: Six years old rhabdomyosarcoma boy with peritoneal dissemination was treated at our facility under COG D9803 protocol (vincristine, dactinomycin, and cyclophosphamide (VAC)). He underwent tumor resection on the 14th week according to the protocol. During surgery, the 2-cm residual tumor was completely resected, but in the pelvis, numerous nodules that were suspected as peritoneal disseminated tumors were observed. We administered 30 Gy/20fr whole abdominopelvic radiotherapy using volumetric modulated arc therapy (VMAT) technique and a 6 Gy sequential boost to pelvis after the surgery and completed the protocol treatment. During the course of treatment, the patient experienced G4 hematological toxicity and received multiple transfusions, particularly after whole abdominopelvic irradiation. He has achieved complete remission and is alive without evidence of recurrence and severe late adverse effect for 3 years. In terms of growth, his height and weight are within the average values for Japanese boys at the same age. CONCLUSION: By using the VMAT technique, a patient with peritoneal disseminated rhabdomyosarcoma can be treated, and a dose of 30 Gy to the whole abdominopelvis with concurrent chemotherapy may be tolerable.

Integration Mapping of piggyBac-Mediated CD19 Chimeric Antigen Receptor T Cells Analyzed by Novel Tagmentation-Assisted PCR.

Insertional mutagenesis is an important risk with all genetically modified cell therapies, including chimeric antigen receptor (CAR)-T cell therapy used for hematological malignancies. Here we describe a new tagmentation-assisted PCR (tag-PCR) system that can determine the integration sites of transgenes without using restriction enzyme digestion (which can potentially bias the detection) and allows library preparation in fewer steps than with other methods. Using this system, we compared the integration sites of CD19-specific CAR genes in final T cell products generated by retrovirus-based and lentivirus-based gene transfer and by the piggyBac transposon system. The piggyBac system demonstrated lower preference than the retroviral system for integration near transcriptional start sites and CpG islands and higher preference than the lentiviral system for integration into genomic safe harbors. Integration into or near proto-oncogenes was similar in all three systems. Tag-PCR mapping is a useful technique for assessing the risk of insertional mutagenesis.

Development of clinical paroxysmal nocturnal haemoglobinuria in children with aplastic anaemia.

The clinical significance of paroxysmal nocturnal haemoglobinuria (PNH) in children with aplastic anaemia (AA) remains unclear. We retrospectively studied 57 children with AA between 1992 and 2010. During the follow-up, five patients developed clinical PNH, in whom somatic PIGA mutations were detected by targeted sequencing. The 10-year probability of clinical PNH development was 10·2% (95% confidence interval, 3·6-20·7%). Furthermore, the detection of minor PNH clones by flow cytometry at AA diagnosis was a risk factor for the subsequent development of clinical PNH. These patients with PNH clones at AA diagnosis should undergo periodic monitoring for potential clinical PNH development.