Chronic hypogammaglobulinemia after allogeneic stem cell transplantation and their treatment with subcutaneous immunoglobulin in pediatric patients.

INTRODUCTION: Hypogammaglobulinemia in the first months after allogeneic hematopoietic stem cell transplantation (HSCT) is common in paediatric patients. During this phase, replacement therapy with human immunoglobulin must be administered parenterally to prevent infections. In some cases, this hypogammaglobulinemia persists over time, which forces further treatment when the patient is usually no longer a carrier of a central line, making them ideal candidates for subcutaneous replacement therapy. There is little published literature describing the use of this method in paediatric patients undergoing HSCT, widely described in replacement treatment in children with primary immunodeficiencies with very good results. PATIENTS AND METHODS: An observational, descriptive, longitudinal and retrospective study is carried out. During the years 2008-2019, we evaluated all paediatric patients undergoing HSCT in our center with persistent chronic hypogammaglobulinemia (for over a year). The treatment phase with intravenous immunoglobulin (Privigen®) and the first four years of treatment with subcutaneous immunoglobulin (Hizentra®) are evaluated using a questionnaire. RESULTS: During the years 2008-2019, 175 patients underwent HSCT, 143 (82%) of whom exceeded three months after transplantation. Three (2%) of them had persistent hypogammaglobulinemia. All three share factors described in the literature involved in immune reconstitution. After analysing the questionnaire, it is observed that switching from intravenous to subcutaneous gammaglobulin has involved a great improvement in their quality of life. CONCLUSIONS: The origin of chronic hypogammaglobulinemia in our patients shows different factors and cannot be attributed to a single cause. Due to the limited number of patients no conclusions can be drawn at the population level. We have been able to observe that replacement treatment with Hizentra 20% has been as effective as the intravenous administration without evidence of an increase in bacterial infections. Furthermore, it has also led to an improvement in quality of life and increased comfort, as the patients themselves have stated.

Three years pilot of spinal muscular atrophy newborn screening turned into official program in Southern Belgium.

Three new therapies for spinal muscular atrophy (SMA) have been approved by the United States Food and Drug Administration and the European Medicines Agency since 2016. Although these new therapies improve the quality of life of patients who are symptomatic at first treatment, administration before the onset of symptoms is significantly more effective. As a consequence, newborn screening programs have been initiated in several countries. In 2018, we launched a 3-year pilot program to screen newborns for SMA in the Belgian region of Liège. This program was rapidly expanding to all of Southern Belgium, a region of approximately 55,000 births annually. During the pilot program, 136,339 neonates were tested for deletion of exon 7 of SMN1, the most common cause of SMA. Nine SMA cases with homozygous deletion were identified through this screen. Another patient was identified after presenting with symptoms and was shown to be heterozygous for the SMN1 exon 7 deletion and a point mutation on the opposite allele. These ten patients were treated. The pilot program has now successfully transitioned into the official neonatal screening program in Southern Belgium. The lessons learned during implementation of this pilot program are reported.

[Reduced-intensity conditioning haematopoietic stem cell transplantation in genetic diseases: Experience of the Spanish Working Group for Bone Marrow Transplantation in Children]. / Trasplante de progenitores hematopoyéticos con intensidad reducida en enfermedades genéticas. Experiencia del grupo GETMON (Grupo Español de Trasplante de Médula Ósea en Niños).

INTRODUCTION: Haematopoietic stem cell transplantation (HSCT) involves implanting cellular elements capable of generating a new and healthy haematopoietic system. Reduced intensity conditioning (RIC) consists of an immunosuppressive treatment to facilitate a progressive implant with lower morbidity. This type of conditioning can also lead to myelosuppression, which is potentially reversible over time. Reduced intensity conditioning enables HSCT to be performed on patients with genetic diseases for whom added comorbidity is undesirable due to the high doses of chemotherapy that accompanies conventional myeloablative regimens. PATIENTS AND METHODS: An analysis was performed on the outcomes of 68 paediatric patients with genetic diseases who underwent HSCT with RIC between 2005 and 2013 in the of Paediatric Haematopoietic Stem Cell Transplantation Units that are part of the Spanish Working Group for Bone Marrow Transplantation in Children. A multicentre study was conducted including 68 patients, of whom 43 had Primary Immunodeficiency, 21 with congenital haematological diseases, and 4 with metabolic diseases. RESULTS: Fifty (73.5%) of the 68 patients were still alive. The Overall Survival (OS) at nine years was 0.74. Twenty-three (33.8%) had some event during the course of the HSCT, with an event-free survival rate of 0.66. The OS in patients with haematological diseases was 0.81, being 0.7 in primary immunodeficiencies, and 0.4 in metabolic diseases. No significant difference was observed between the 3 groups of diseases. As regards the source of haematopoietic progenitors, there was an OS rate of 0.74 in patients transplanted with peripheral blood, 0.70 with bone marrow, and 0.70 and with cord blood, with no statistically significant differences. CONCLUSIONS: Favourable results have been obtained in HSCT with reduced intensity conditioning in genetic diseases. It should be noted that the risks and benefits of the RIC in patients with metabolic diseases need to be assessed on an individual basis.