Extracorporeal photopheresis in paediatric patients: A retrospective comparison between different 'off-line' protocols.

BACKGROUND AND OBJECTIVES: Extracorporeal photopheresis (ECP) has been shown to be an effective treatment for graft-versus-host disease (GvHD). However, information regarding lymphocyte collection for ECP in children is limited. The aim of this study was to analyse and compare lymphocyte collection for ECP in children using different devices and protocols. Moreover, we have studied both safety and variables of the infused product related to treatment efficacy. PATIENTS AND METHODS: This was a retrospective study of 91 patients who underwent 1524 apheresis procedures with either the COBE Spectra or Spectra Optia system. The comparison study between the Optia protocols (MNC and CMNC) was prioritized. We analysed 578 procedures using the Optia blood cell separator: 204 and 374 using the MNC and the CMNC protocol, respectively. RESULTS: The Optia CMNC protocol showed better collection efficiency, with increased lymphocyte collection per kg of body weight (p < 0.001). On multivariate analysis, the type of protocol showed no relationship with haematocrit or platelet loss. Most procedures were well-tolerated, with the most frequent adverse events related to venous access (21.7%). Seventy-one percent of patients had either partial or complete clinical GvHD response. In the multivariate model, only two variables were associated with a better response to ECP, younger age and a greater increase of B lymphocytes after treatment. CONCLUSION: Lymphocyte collection for ECP is well-tolerated in most children, achieving complete or partial response in more than half of GvHD patients. CMNC is the optimal software to perform lymphocyte collection in children.

Mobilization with high-dose granulocyte colony-stimulating factor alone at 12 µg/kg twice a day in high-risk pediatric patients: A retrospective analysis of the experience in a single center.

INTRODUCTION: Mobilization regimes in pediatric patients at high risk for poor mobilization are not standardized across different institutions. We present a retrospective analysis of our experience with a high-dose granulocyte colony-stimulating factor (G-CSF) regime of 12 µg/Kg per body weight (BW) twice a day for 4 days used in high-risk patients. MATERIAL AND METHODS: We report the results of all pediatric patients mobilized with high-dose G-CSF between January 1999 and February 2021 in our center. A successful mobilization was defined as a peripheral blood (PB) CD34+ cell count of ≥10 CD34+ cells/µl on the fifth day of mobilization immediately before leukapheresis. A minimum cell yield of ≥2 × 106 CD34+ cells/Kg of BW was required for a successful collection. RESULTS: Of the 262 patients included in the analysis, mobilization failure was found in 27 (10.3%). In a univariate analysis, this was associated with age, weight, baseline diagnosis, and having undergone a previous mobilization cycle, the latter being the only factor that remained significantly associated in a multivariate analysis (P = 0.03). The 54 patients (20.6%) did not reach the minimum required CD34+ cell yield. 50.4% of the patients reported adverse events (AEs) during the mobilization period, and 23 (9.1%) reported 3 or more concomitant AEs. However, all of them were mild and did not affect the mobilization schedule. CONCLUSIONS: Although most high-risk pediatric patients are successfully mobilized with the high-dose G-CSF regime, this approach does not salvage all of them and significantly increases the presence of AEs in comparison to standard-dose regimes.

Defibrotide in hematopoietic stem cell transplantation: A multicenter survey study of the Spanish Hematopoietic Stem Cell Transplantation Group (GETH).

BACKGROUND: Defibrotide is approved in European Union for the treatment of severe sinusoidal obstruction syndrome (SOS) after HSCT. However, it has also been used for SOS prophylaxis, moderate SOS and in other complications such as transplant-associated thrombotic microangiopathy (TAM). The objective of this study was to evaluate current uses, effectiveness and safety of defibrotide in patients with HSCT. METHODS: This multicenter, retrospective study included patients treated with defibrotide for any indication at 28 HSCT centers of the Grupo Español de Trasplante Hematopoyetico (GETH) including the pediatric subgroup Grupo Español de Trasplante de Medula en Niños (GETMON). RESULTS: Three hundred and eighty eight patients treated with defibrotide between January 2011 and December 2018 were included. 253 patients were children, and 135 patients were adults. In total, 332 transplants were allogeneic, and the remainder were autologous. Main indications for defibrotide use were severe/very severe SOS in 173 patients, SOS prophylaxis in 135 patients, moderate SOS in 41 patients, TAM in six patients and suspected SOS in 33 patients. Overall survival (OS) at day +100 in the SOS prophylaxis group was 89% (95% CI, 87%-91%). In the group of patients with moderate and severe/very severe SOS, the OS at day +100 was 80% (95% CI, 74%-86%) and 62% (95% CI, 59%-65%), respectively (P = .0015). With a longer follow-up, median of 2 years (4 months-7 years), OS was 63% (95% CI, 59%-67%) in the SOS prophylaxis patients. OS for patients with moderate and severe/very severe SOS groups was 53% (95% CI, 47%-61%) and 26% (95% CI, 22%-30%), respectively (P = .006). 191 patients died, and SOS was the main cause of death in 23 patients (12%). CONCLUSIONS: Defibrotide has an acceptable safety profile with an improved response in severe/very severe SOS compared with historical controls, mainly in pediatric patients. Use of defibrotide for prophylaxis may improve prognosis of patients at high risk of complications due to endothelial damage such as those who receive a second transplant. SOS has an important impact on the HSCT long-term survival, as can be concluded from our study.

Secondary immune thrombocytopenia in children: Characteristics and outcome of a large cohort from two Spanish centres.

AIM: To evaluate the incidence and outcome of secondary immune thrombocytopenia (ITP) in a large cohort of paediatric Spanish patients. METHODS: A retrospective observational study was conducted in two paediatric University hospitals in Spain between 2009 and 2019, which included children from 4 months to 18 years old diagnosed with ITP. Data were recorded from clinical charts: gender, age at diagnosis, coexisting condition and associated characteristics, outcome and treatment. RESULTS: Secondary ITP was diagnosed in 87 out of 442 patients (19.6%). Post-immunisation ITP was seen in younger children. The onset of secondary ITP to autoimmune diseases (AD) and immunodeficiencies (ID) was at an older age and had more tendency to be insidious, and platelet level was higher than primary ITP. Mean time from ITP onset to AD diseases or ID diagnosis was 1.2 and 2.6 years, respectively. Whereas the cumulative incidence of remission was significantly higher in post-immunisation and post-viral infection (compared with primary ITP patients), it was worse in AD and ID patients. CONCLUSIONS: Identification of secondary ITP is important as it predicts outcome. Most of them are diagnosed at ITP onset, but AD diseases and ID should be ruled out periodically as they are usually identified later.

Ruxolitinib treatment for steroid refractory acute and chronic graft vs host disease in children: Clinical and immunological results.

Ruxolitinib is a promising treatment for steroid refractory graft-vs-host disease (GvHD). However, data concerning effects on T cells are probably involved in increased risk of opportunistic infections. We analyzed clinical and immunological changes in children with GvHD taking ruxolitinib. Twenty-two children that underwent transplantation and received ruxolitinib were included. Ruxolitinib indication was acute and chronic GvHD in 13 and 9 patients, respectively. Overall response rate (ORR) in acute GvHD and chronic GvHD was high, of 77% and 89%, respectively. Ruxolitinib was associated with an increase in CD4 effector memory (EM), and decrease of CD4 central memory percentage. CD4 regulatory T cells percentage decreased significantly. Patients who achieved complete response to ruxolitinib had higher natural killer (NK) cells before ruxolitinib that patients who did not respond. Also there was an increase of CD4 lymphocytes percentage, with decrease of CD8 and NK cells percentage in responders against non-responders. There were 54%, 18% and 13% of infections caused by virus, bacteria and fungi, respectively. Cumulative incidence of relapse and non-relapse mortality was 19 ± 9%and 28 ± 10%, respectively. Overall survival and disease-free survival rate at 2 years were 62 ± 11% and 58 ± 11%, respectively. Ruxolitinib is a promising treatment for acute and chronic GvHD with a high ORR of 77% and 89%, respectively. It produces important changes in immune system, such as increase of CD4 EM cells and decrease in NK and regulatory T cells. Now, we need pharmacokinetic studies to determine ruxolitinib dose in children and close surveillance and antimicrobial prophylaxis.

Optical Genome Mapping as a New Tool to Overcome Conventional Cytogenetics Limitations in Patients with Bone Marrow Failure.

Cytogenetic studies are essential in the diagnosis and follow up of patients with bone marrow failure syndromes (BMFSs), but obtaining good quality results is often challenging due to hypocellularity. Optical Genome Mapping (OGM), a novel technology capable of detecting most types chromosomal structural variants (SVs) at high resolution, is being increasingly used in many settings, including hematologic malignancies. Herein, we compared conventional cytogenetic techniques to OGM in 20 patients with diverse BMFSs. Twenty metaphases for the karyotype were only obtained in three subjects (15%), and no SVs were found in any of the samples. One patient with culture failure showed a gain in chromosome 1q by fluorescence in situ hybridization, which was confirmed by OGM. In contrast, OGM provided good quality results in all subjects, and SVs were detected in 14 of them (70%), mostly corresponding to cryptic submicroscopic alterations not observed by standard techniques. Therefore, OGM emerges as a powerful tool that provides complete and evaluable results in hypocellular BMFSs, reducing multiple tests into a single assay and overcoming some of the main limitations of conventional techniques. Furthermore, in addition to confirming the abnormalities detected by conventional techniques, OGM found new alterations beyond their detection limits.

Management of primary immune thrombocytopenia. A comparison between two historical cohorts.

INTRODUCTION: In recent years, there have been changes in the management of patients with primary immune thrombocytopenia. In this study, a review is presented of the characteristics and outcomes of children with primary immune thrombocytopenia in a children's hospital (Hospital Infantil Niño Jesús). Moreover, an analysis is made of the changes in the care of these patients diagnosed before and after 2011, when new guidelines were published by the Spanish Society of Paediatric Haematology Oncology (SEHOP). MATERIAL AND METHODS: Data from a cohort of primary immune thrombocytopenia patients followed up in this hospital have been retrospectively reviewed. The statistical package used for the analysis was SPSS Statistics 22.0 (IBM Corp., Chicago, IL, USA). RESULTS: A review is presented on the clinical data from 235 paediatric patients diagnosed with primary immune thrombocytopenia. It was observed that some features at diagnosis, such as age younger than five years and a previous history of infection, influenced the probability of cure. Regarding the changes in the management of patients since 2011, the steroid doses received during the first month and the first year, and the number of days corresponding to the patient's first admission have both significantly decreased. Splenectomies were also significantly reduced. CONCLUSIONS: Since 2011, there have been changes in the medical care of our primary immune thrombocytopenia patients: they receive lower doses of steroids, they stay fewer days in the hospital, and the number of splenectomies has decreased without increasing bleeding or worsening the clinical evolution. Furthermore, it was observed that age younger than 5 years and a history of infection prior to diagnosis were related to higher chances of recovery.