Haploidentical Stem Cell Transplant with Post-Transplant Cyclophosphamide in Pediatric Hemophagocytic Lymphohistiocytosis.

PURPOSE: Primary hemophagocytic lymphohistiocytosis is a severe and uncommon disease affecting pediatric patients. Genetic abnormalities have been related to altered apoptosis and exaggerated inflammatory reactions. Chemoimmunotherapy and stem cell transplantation are treatment options, but transplant is the only curative treatment. Here we aim to describe the treatment with hematopoietic stem cell transplantation with a novel strategy and the outcomes. METHODS: An observational, descriptive, case series study was performed in pediatric patients of two high complexity medical centers in Colombia. Data was collected retrospectively between 2015 and 2020. RESULTS: We describe five pediatric cases with a diagnosis of primary hemophagocytic lymphohistiocytosis. All were treated with replete-cell haploidentical hematopoietic stem transplantation, reduced-intensity conditioning, and post-transplant cyclophosphamide, in two high-complexity centers in Colombia. All patients are alive, and one is receiving management for chronic graft-versus-host disease. CONCLUSION: To the best of our knowledge, there are few reports in the literature with this strategy, promising a possible alternative when there are no other donor options.

Fludarabine-Based Reduced-Intensity Conditioning Regimen for Hematopoietic Stem Cell Transplantation in a Pediatric Patient with Sickle Cell Disease: A Case Report.

Reduced-intensity conditioning (RIC) regimens have the potential to decrease toxicities related to hematopoietic stem cell transplantation (HCT) in patients with sickle cell disease (SCD). While initial results may have been acceptable in adults and young adults, there are no well-established strategies in children with SCD. Here, it is described the clinical course of two children with symptomatic SCD who have successfully undergone HSCT using Fludarabin-based conditioning.

Pediatric Adapted Risk index (PARI) to predict 2-year transplant related mortality post-HSCT in children.

Several attempts have been made to optimize pre-transplant risk assessment to improve hematopoietic stem cell transplantation (HSCT) decision-making and to predict outcome post- HSCT. However, its relevance to the pediatric population remains unclear. We report the results of revalidation of the HCT-CI in 874 children who received 944 HSCTs for malignant or non-malignant diseases at a single centre. After finding the HCT-CI invalid in our patient population; we proposed a modified pediatric adapted scoring system that captures risk factors (RF) and comorbidities (CoM) relevant to pediatrics. Each RF/CoM was assigned an integer weight based on its hazard ratio (HR) for TRM; 0 (HR <1.2), 1 (1.2 ≥HR <1.75), 2 (1.75 ≥HR <2.5), 3 (HR ≥2.5) .Using these weights, the pediatric adapted HSCT-RI (PARI) was devised, and patients were divided into 4 risk groups; group 1 without RF/CoM, group 2: scores 1-2, group 3: scores 3-4, group 4: scores ≥5. There was a linear increase in 2-year TRM from group 1 to 4 (TRM= 6.2% in group 1, 50.9% in group 4). PARI was successfully validated on an internal and external cohort of pediatric patients. Comparing models using c-statistics, PARI was found to be a better model than HCT-CI in predicting 2-year TRM in children with Akaike's and Schwarz's Bayesian information criteria (AIC and BIC) of 1069.245 and 1073.269; respectively using PARI vs 1223.158 and 1227.051; respectively using HCT-CI. We believe that PARI will be a valuable tool enabling better counselling and decision making for pediatric HSCT patients.

Side Effects After Use of Bedside Thaw Method for Umbilical Cord Blood Stem Cell Allogeneic Transplantations in a Pediatric Cohort: A Single-center Experience.

BACKGROUND AND OBJECTIVES: Several strategies and procedures have been described for thawing umbilical cord blood (UCB) products. The ideal method for each center depends on the resources, staff training, and access to each of these. We retrospectively evaluated the incidence of side effects using the bedside thaw method after unrelated UCB transplantation. PATIENTS AND METHODS: For 34 children, patient, donor, graft characteristics, and side effects were identified. In addition, we attempted to identify the risk factors that could be associated with side effects. RESULTS: 68% of patients experienced any adverse reaction. All the reactions were mild and transient events. The most frequent side effects were vomiting, hypertension, hemolytic reactions, and fever. There were more gastrointestinal events with a faster infusion rate. CONCLUSION: The thawed at the bedside method is a practical, easy, and safe technique for cord blood transplantation in pediatric-patient settings.

Langerhans cell histiocytosis: Case report and literature review / Histiocitosis de células de Langerhans: reporte de caso y revisión de la literatura.

Histiocytosis comprises a heterogeneous group of inflammatory diseases whose main cellular components are dendritic cells and macrophages. The inflammatory infiltrate can affect the skin and other organs and the clinical outcome varies from mild to fatal depending on the involved cell subset and multisystemic compromise. Delay in diagnosis may occur due to its non-specific presentation and to a low suspicion on the part of the clinician. We report the case of an infant who despite multiple consultations with nonspecific but characteristic symptoms of the disease was only finally diagnosed thanks to histopathological findings.

La histiocitosis de células de Langerhans comprende un grupo heterogéneo de enfermedades inflamatorias cuyos principales componentes celulares son las células dendríticas y los macrófagos. El infiltrado inflamatorio puede afectar la piel y otros órganos, y el resultado clínico varía de leve a letal, dependiendo del subconjunto de células involucradas y el compromiso multisistémico. La demora en el diagnóstico puede ocurrir debido a su presentación inespecífica y a que los médicos tratantes no suelen sospecharla. Se reporta el caso de una lactante mayor a la cual, a pesar de múltiples consultas con síntomas inespecíficos pero característicos de la enfermedad, solamente se le pudo hacer el diagnóstico gracias a los hallazgos histopatológicos.

[Refractory kaposiforme hemangioendothelioma in the pediatric population: case report and literature review.] / Hemangioendotelioma kaposiforme refractario en población pediátrica: reporte de caso y revisión de la literatura.

INTRODUCCIÓN: El hemangioendotelioma kaposiforme (HEK) es un tumor vascular poco frecuente caracterizado por una invasión local agresiva y un síndrome de atrapamiento de plaquetas conocido como fenómeno de Kasabach-Merritt. Aunque muchos casos de HEK se tratan con éxito con control local o quimioterapia de baja intensidad, otros son resistentes y se cuenta con pocas opciones terapéuticas. El objetivo de este reporte es mostrar la experiencia del tratamiento con sirolimus por vía oral en un paciente pediátrico con HEK asociado a fenómeno de Kasabach-Merritt refractario al tratamiento de primera línea, quien mostró excelente respuesta al tratamiento. CASO CLÍNICO: Paciente de sexo masculino de 3 meses con un HEK refractario al manejo de primera línea (corticoides, propranolol, vincristina), sin posibilidad de hacer control local, por lo que se decide terapia combinada con sirolimus, presentando control local y resolución de la coagulopatía desde la primera semana de iniciado el manejo y con resolución de la malformación vascular después de 12 meses de seguimiento. CONCLUSIONES: Aunque no existen pautas claras para el tratamiento del HEK refractario en la edad pediátrica, la evidencia actual demuestra que el sirolimus es un medicamento eficaz que puede ser considerado como opción terapéutica de primera línea en estos pacientes. BACKGROUND: Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor characterized by aggressive local invasion and a platelet entrapment syndrome known as the Kasabach-Merritt phenomenon. Although many cases of KHE are successfully treated with local control or low-intensity chemotherapy, some cases are often resistant, with few therapeutic options available. Here, we report a pediatric patient with KHE associated with Kasabach-Merritt phenomenon refractory to first-line treatment, who demonstrated excellent response to treatment. CASE REPORT: We present the case of a 3-month-old male patient with a KHE refractory to first-line treatment (vincristine, corticosteroids, propranolol), without possibility of local control treatment. Therefore, combined therapy with sirolimus was decided, presenting local control and resolution of the coagulopathy from the first week after starting the management and with resolution of vascular malformation after 12 months of ­follow-up. CONCLUSIONS: Although there are no clear guidelines for the treatment of refractory KHE in the pediatric population, current evidence demonstrate that sirolimus is an effective option that could be considered as a first-line treatment in such patients.

New insights into risk factors for transplant-associated thrombotic microangiopathy in pediatric HSCT.

This study aimed to identify a risk profile for development of transplant-associated thrombotic microangiopathy (TA-TMA) in children undergoing hematopoietic stem cell transplantation (HSCT). Between 2013 and 2016, 439 children underwent 474 HSCTs at 2 supraregional United Kingdom centers. At a median of 153 days post-HSCT, TA-TMA occurred among 25 of 441 evaluable cases (5.6%) with no evidence of center variation. Sex, underlying disease, intensity of the conditioning, total body irradiation-based conditioning, the use of calcineurin inhibitors, venoocclusive disease, and viral reactivation did not influence the development of TA-TMA. Donor type: matched sibling donor/matched family donor vs matched unrelated donor vs mismatched unrelated donor/haplo-HSCT, showed a trend toward the development of TA-TMA in 1.8% vs 6.1% vs 8.3%, respectively. Presence of active comorbidity was associated with an increased risk for TA-TMA; 13% vs 3.7% in the absence of comorbidity. The risk of TA-TMA was threefold higher among patients who received >1 transplant. TA-TMA rates were significantly higher among patients with acute graft-versus-host disease (aGVHD) grades III to IV vs aGVHD grade 0 to II. On multivariate analysis, the presence of active comorbidity, >1 transplant, aGVHD grade III to IV were risk factors for TA-TMA (odds ratio [OR]: 5.1, 5.2, and 26.9; respectively), whereas the use of cyclosporine A/tacrolimus-based GVHD prophylaxis was not a risk factor for TA-TMA (OR: 0.3). Active comorbidity, subsequent transplant, and aGVHD grades III to IV were significant risk factors for TA-TMA. TA-TMA might represent a form of a vascular GVHD, and therefore, continuing control of aGVHD is important to prevent worsening of TA-TMA associated with GVHD.

Histiocitosis de células de Langerhans: reporte de caso y revisión de la literatura / Langerhans cell histiocytosis: Case report and literature review

Resumen La histiocitosis de células de Langerhans comprende un grupo heterogéneo de enfermedades inflamatorias cuyos principales componentes celulares son las células dendríticas y los macrófagos. El infiltrado inflamatorio puede afectar la piel y otros órganos, y el resultado clínico varía de leve a letal, dependiendo del subconjunto de células involucradas y el compromiso multisistémico. La demora en el diagnóstico puede ocurrir debido a su presentación inespecífica y a que los médicos tratantes no suelen sospecharla. Se reporta el caso de una lactante mayor a la cual, a pesar de múltiples consultas con síntomas inespecíficos pero característicos de la enfermedad, solamente se le pudo hacer el diagnóstico gracias a los hallazgos histopatológicos.

Abstract Histiocytosis comprises a heterogeneous group of inflammatory diseases whose main cellular components are dendritic cells and macrophages. The inflammatory infiltrate can affect the skin and other organs and the clinical outcome varies from mild to fatal depending on the involved cell subset and multisystemic compromise. Delay in diagnosis may occur due to its non-specific presentation and to a low suspicion on the part of the clinician. We report the case of an infant who despite multiple consultations with nonspecific but characteristic symptoms of the disease was only finally diagnosed thanks to histopathological findings.

Hemangioendotelioma kaposiforme refractario en población pediátrica: reporte de caso y revisión de la literatura / Refractory kaposiforme hemangioendothelioma in the pediatric population: case report and literature review

Resumen Introducción: El hemangioendotelioma kaposiforme (HEK) es un tumor vascular poco frecuente caracterizado por una invasión local agresiva y un síndrome de atrapamiento de plaquetas conocido como fenómeno de Kasabach-Merritt. Aunque muchos casos de HEK se tratan con éxito con control local o quimioterapia de baja intensidad, otros son resistentes y se cuenta con pocas opciones terapéuticas. El objetivo de este reporte es mostrar la experiencia del tratamiento con sirolimus por vía oral en un paciente pediátrico con HEK asociado a fenómeno de Kasabach-Merritt refractario al tratamiento de primera línea, quien mostró excelente respuesta al tratamiento. Caso clínico: Paciente de sexo masculino de 3 meses con un HEK refractario al manejo de primera línea (corticoides, propranolol, vincristina), sin posibilidad de hacer control local, por lo que se decide terapia combinada con sirolimus, presentando control local y resolución de la coagulopatía desde la primera semana de iniciado el manejo y con resolución de la malformación vascular después de 12 meses de seguimiento. Conclusiones: Aunque no existen pautas claras para el tratamiento del HEK refractario en la edad pediátrica, la evidencia actual demuestra que el sirolimus es un medicamento eficaz que puede ser considerado como opción terapéutica de primera línea en estos pacientes.

Abstract Background: Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor characterized by aggressive local invasion and a platelet entrapment syndrome known as the Kasabach-Merritt phenomenon. Although many cases of KHE are successfully treated with local control or low-intensity chemotherapy, some cases are often resistant, with few therapeutic options available. Here, we report a pediatric patient with KHE associated with Kasabach-Merritt phenomenon refractory to first-line treatment, who demonstrated excellent response to treatment. Case report: We present the case of a 3-month-old male patient with a KHE refractory to first-line treatment (vincristine, corticosteroids, propranolol), without possibility of local control treatment. Therefore, combined therapy with sirolimus was decided, presenting local control and resolution of the coagulopathy from the first week after starting the management and with resolution of vascular malformation after 12 months of follow-up. Conclusions: Although there are no clear guidelines for the treatment of refractory KHE in the pediatric population, current evidence demonstrate that sirolimus is an effective option that could be considered as a first-line treatment in such patients.